Spine

Pedicle subtraction osteotomies (PSOs) have been used in the treatment of multiple spinal conditions involving a fixed sagittal imbalance, such as degenerative scoliosis, idiopathic scoliosis, posttraumatic deformities, iatrogenic flatback syndrome, and ankylosing spondylitis. The procedure was first described by Thomasen¹ for the treatment of ankylosing spondylitis. More recently, multiple centers have reported the expanded use and good success of PSO in the treatment of fixed sagittal imbalance of other etiologies.^2,3 According to Bridwell and colleagues,² lumbar lordosis can be increased 34.1°, and sagittal plumb line can be improved 13.5 cm.

PSO is a complex, extensive surgery most often performed in the revision setting. Multiple authors have described the technique for PSO.^4,5 There are significant technical challenges and many complications, including neurologic deficits, pseudarthrosis of adjacent levels, and wound infections.⁶ Short-term challenges include a large loss of blood, 2.4 L on average, according to Bridwell and colleagues.⁶ Time of closure of the osteotomy gap is a crucial point in the surgery. Blood loss, often large, slows only after the gap is closed and stabilized.

In this article, we describe a technique in which an additional rod or pedicle screw construct is used at the periosteotomy levels to close the osteotomy gap during PSO and simplify subsequent instrumentation. In addition, we report our experience with the procedure.

Materials and Methods

Seventeen consecutive patients (mean age, 58 years; range, 12-81 years) with fixed sagittal imbalance were treated with lumbar PSO. The indication in all cases was flatback syndrome after previous spinal surgery. Mean follow-up was 13 months. Mean number of prior surgeries was 3. Thirteen PSOs were performed at L3, and 4 were performed at L2.

Radiographic data were collected from before surgery, in the immediate postoperative period, and at final follow-up. All the radiographs were standing films. Established radiographic parameters were measured: thoracic kyphosis from T5 to T12, lumbar lordosis from L1 to S1, PSO angle (1 level above to 1 level below osteotomy level), sagittal plumb line (from center of C7 body to posterosuperior aspect of S1 body), and coronal plumb line (from center of C7 body to center of S1 body).²

Good clinical outcomes in the treatment of spinal disorders require careful attention to the alignment of the spine in the sagittal plane.^7,8 When evaluating the preoperative radiographs, we measured and documented pelvic parameters. Figure 1A shows how pelvic incidence was determined. We measured this as the angle between a line drawn from the center of the S1 endplate to the center of the femoral head and the perpendicular off the S1 endplate. Figure 1B shows pelvic tilt as determined by the angle between a line drawn from the center of S1 to the femoral head and a vertical line originating from the center of the femoral head. Figure 1C shows the sacral slope, which we measured as the angle between a line drawn parallel to the endplate of S1 and its intersection with a horizontal line.

Surgical Technique

The overall surgical technique for PSO has been well described.^4,5 Here we describe the “outrigger” modification to osteotomy closure (Figures 2, 3).

Most of our 17 cases were revisions. In these cases, new fixation points are first established. All fixation points that will be needed for the final fusion are placed. If a pedicle above or below the osteotomy level is not suitable for a screw, it can be skipped.

Wide decompression of the involved level is performed from pedicle to pedicle, ensuring that the nerve roots are completely decompressed. The dissection is then continued around the lateral wall of the vertebral body. While the neural elements are protected with gentle retraction, the pedicle and a portion of the posterior aspect of the vertebral body are removed with a combination of a rongeur and reverse-angle curettes. Resection of the vertebral body can be facilitated by attaching a short rod to the pedicle screws on either side of the osteotomy level and using it to provide gentle distraction.

Once sufficient bone has been removed to close the osteotomy, short rods are placed in the pedicle screws in the level above and the level below the osteotomy site. These rods are attached with offset connectors that allow the rods to be placed lateral to the screws. Before the surgical procedure is started, the patient is positioned on 2 sets of posts separated by the break in the table. The break in the table allows flexion to accommodate the preoperative kyphosis and allows hyperextension to help close the osteotomy site. Now, with the osteotomy site ready for closure, the table is gradually positioned in extension along with a combination of posterior pressure and compression between the pedicle screws above and below the osteotomy. Once the osteotomy is adequately compressed, the short rods are tightened, holding the osteotomy in good position. With the osteotomy held by the short rods and table positioning, decompression of the neural elements is confirmed and hemostasis obtained.

Final instrumentation is then performed with long rods that can bypass the osteotomized levels, allowing for simpler contouring. If desired, a cross connector can be placed between the long rod of the fusion construct and the short rod holding the osteotomy. The rest of the fusion procedure is completed in standard fashion with at least 1 subfascial drain.

Results

Our 17 patients’ results are summarized in the Table. Mean sagittal plumb line improved from 17.7 cm (range, 5.9 to 29 cm) before surgery to 4.5 cm (range, –0.2 to 12.9 cm) after surgery, for a mean improvement of 13.2 cm. At final follow-up, mean sagittal plumb line was 5.1 cm (range, –1.4 to 10.2 cm).

Mean lumbar lordosis improved from 10° (range, –14° to 34°) before surgery to 49° (range, 36° to 63°) after surgery, for a mean improvement of 39°. Mean PSO angle improved from 3° (range, –36° to 23°) before surgery to 41° (range, 25° to 65°) after surgery, for a mean improvement of 38°. At final follow-up, mean lumbar lordosis remained at 47° (range, 26° to 64°), and mean PSO angle was 39° (range, 24° to 59°).

Mean thoracic kyphosis improved from 18° (range, –8° to 52°) before surgery to 30° (range, 3° to 58°) after surgery, for a mean improvement of 12°. At final follow-up, mean thoracic kyphosis was 31° (range, 2° to 57°).

Fourteen patients did not have complications during the study period. Of the 3 patients with complications, 1 had an early infection, treated effectively with irrigation and débridement and intravenous antibiotics; 1 had a late deep infection, treated with multiple débridements, hardware removal, and, eventually, suppressive antibiotics; and 1 had cauda equina syndrome (caused by extensive scar tissue on the dura, which buckled with restoration of lordosis leading to cord compression), treated with duraplasty, which resulted in full neurologic recovery.

Discussion

In the present series of patients, the described technique for facilitating PSO for correction of sagittal imbalance was effective, and complications were similar to those previously reported.

The benefit of the outrigger construct is that it allows controlled compression of the osteotomy site and can be left in place at time of final instrumentation, locking in compression and correction. Other techniques involve removing the temporary rod and replacing it with final instrumentation^4,5—an extra step that complicates instrumentation of the additional levels of the fusion construct and possibly adds pedicle screw stress and contributes to loosening when the new rod is reduced to the pedicle screw. The final long rod construct can bypass the osteotomy levels and allow for simpler instrumentation.

 Mean age was 58 years in this series versus 52.4 years in the series reported by Bridwell and colleagues.² Given the higher mean age of our patients, though no objective measures of bone quality were available, this technique is likely applicable to patients with poor bone quality.

The complications we have reported are in line with those reported in previous series, and maintenance of radiographic parameters at final follow-up indicates that this osteotomy technique allows for solid fusion constructs.

The outrigger technique for controlling PSO closure is an effective method that simplifies instrumentation during a complex revision case.

Pedicle subtraction osteotomies (PSOs) have been used in the treatment of multiple spinal conditions involving a fixed sagittal imbalance, such as degenerative scoliosis, idiopathic scoliosis, posttraumatic deformities, iatrogenic flatback syndrome, and ankylosing spondylitis. The procedure was first described by Thomasen¹ for the treatment of ankylosing spondylitis. More recently, multiple centers have reported the expanded use and good success of PSO in the treatment of fixed sagittal imbalance of other etiologies.^2,3 According to Bridwell and colleagues,² lumbar lordosis can be increased 34.1°, and sagittal plumb line can be improved 13.5 cm.

PSO is a complex, extensive surgery most often performed in the revision setting. Multiple authors have described the technique for PSO.^4,5 There are significant technical challenges and many complications, including neurologic deficits, pseudarthrosis of adjacent levels, and wound infections.⁶ Short-term challenges include a large loss of blood, 2.4 L on average, according to Bridwell and colleagues.⁶ Time of closure of the osteotomy gap is a crucial point in the surgery. Blood loss, often large, slows only after the gap is closed and stabilized.

In this article, we describe a technique in which an additional rod or pedicle screw construct is used at the periosteotomy levels to close the osteotomy gap during PSO and simplify subsequent instrumentation. In addition, we report our experience with the procedure.

Materials and Methods

Seventeen consecutive patients (mean age, 58 years; range, 12-81 years) with fixed sagittal imbalance were treated with lumbar PSO. The indication in all cases was flatback syndrome after previous spinal surgery. Mean follow-up was 13 months. Mean number of prior surgeries was 3. Thirteen PSOs were performed at L3, and 4 were performed at L2.

Radiographic data were collected from before surgery, in the immediate postoperative period, and at final follow-up. All the radiographs were standing films. Established radiographic parameters were measured: thoracic kyphosis from T5 to T12, lumbar lordosis from L1 to S1, PSO angle (1 level above to 1 level below osteotomy level), sagittal plumb line (from center of C7 body to posterosuperior aspect of S1 body), and coronal plumb line (from center of C7 body to center of S1 body).²

Good clinical outcomes in the treatment of spinal disorders require careful attention to the alignment of the spine in the sagittal plane.^7,8 When evaluating the preoperative radiographs, we measured and documented pelvic parameters. Figure 1A shows how pelvic incidence was determined. We measured this as the angle between a line drawn from the center of the S1 endplate to the center of the femoral head and the perpendicular off the S1 endplate. Figure 1B shows pelvic tilt as determined by the angle between a line drawn from the center of S1 to the femoral head and a vertical line originating from the center of the femoral head. Figure 1C shows the sacral slope, which we measured as the angle between a line drawn parallel to the endplate of S1 and its intersection with a horizontal line.

Surgical Technique

The overall surgical technique for PSO has been well described.^4,5 Here we describe the “outrigger” modification to osteotomy closure (Figures 2, 3).

Most of our 17 cases were revisions. In these cases, new fixation points are first established. All fixation points that will be needed for the final fusion are placed. If a pedicle above or below the osteotomy level is not suitable for a screw, it can be skipped.

Wide decompression of the involved level is performed from pedicle to pedicle, ensuring that the nerve roots are completely decompressed. The dissection is then continued around the lateral wall of the vertebral body. While the neural elements are protected with gentle retraction, the pedicle and a portion of the posterior aspect of the vertebral body are removed with a combination of a rongeur and reverse-angle curettes. Resection of the vertebral body can be facilitated by attaching a short rod to the pedicle screws on either side of the osteotomy level and using it to provide gentle distraction.

Once sufficient bone has been removed to close the osteotomy, short rods are placed in the pedicle screws in the level above and the level below the osteotomy site. These rods are attached with offset connectors that allow the rods to be placed lateral to the screws. Before the surgical procedure is started, the patient is positioned on 2 sets of posts separated by the break in the table. The break in the table allows flexion to accommodate the preoperative kyphosis and allows hyperextension to help close the osteotomy site. Now, with the osteotomy site ready for closure, the table is gradually positioned in extension along with a combination of posterior pressure and compression between the pedicle screws above and below the osteotomy. Once the osteotomy is adequately compressed, the short rods are tightened, holding the osteotomy in good position. With the osteotomy held by the short rods and table positioning, decompression of the neural elements is confirmed and hemostasis obtained.

Final instrumentation is then performed with long rods that can bypass the osteotomized levels, allowing for simpler contouring. If desired, a cross connector can be placed between the long rod of the fusion construct and the short rod holding the osteotomy. The rest of the fusion procedure is completed in standard fashion with at least 1 subfascial drain.

Results

Our 17 patients’ results are summarized in the Table. Mean sagittal plumb line improved from 17.7 cm (range, 5.9 to 29 cm) before surgery to 4.5 cm (range, –0.2 to 12.9 cm) after surgery, for a mean improvement of 13.2 cm. At final follow-up, mean sagittal plumb line was 5.1 cm (range, –1.4 to 10.2 cm).

Mean lumbar lordosis improved from 10° (range, –14° to 34°) before surgery to 49° (range, 36° to 63°) after surgery, for a mean improvement of 39°. Mean PSO angle improved from 3° (range, –36° to 23°) before surgery to 41° (range, 25° to 65°) after surgery, for a mean improvement of 38°. At final follow-up, mean lumbar lordosis remained at 47° (range, 26° to 64°), and mean PSO angle was 39° (range, 24° to 59°).

Mean thoracic kyphosis improved from 18° (range, –8° to 52°) before surgery to 30° (range, 3° to 58°) after surgery, for a mean improvement of 12°. At final follow-up, mean thoracic kyphosis was 31° (range, 2° to 57°).

Fourteen patients did not have complications during the study period. Of the 3 patients with complications, 1 had an early infection, treated effectively with irrigation and débridement and intravenous antibiotics; 1 had a late deep infection, treated with multiple débridements, hardware removal, and, eventually, suppressive antibiotics; and 1 had cauda equina syndrome (caused by extensive scar tissue on the dura, which buckled with restoration of lordosis leading to cord compression), treated with duraplasty, which resulted in full neurologic recovery.

Discussion

In the present series of patients, the described technique for facilitating PSO for correction of sagittal imbalance was effective, and complications were similar to those previously reported.

The benefit of the outrigger construct is that it allows controlled compression of the osteotomy site and can be left in place at time of final instrumentation, locking in compression and correction. Other techniques involve removing the temporary rod and replacing it with final instrumentation^4,5—an extra step that complicates instrumentation of the additional levels of the fusion construct and possibly adds pedicle screw stress and contributes to loosening when the new rod is reduced to the pedicle screw. The final long rod construct can bypass the osteotomy levels and allow for simpler instrumentation.

 Mean age was 58 years in this series versus 52.4 years in the series reported by Bridwell and colleagues.² Given the higher mean age of our patients, though no objective measures of bone quality were available, this technique is likely applicable to patients with poor bone quality.

The complications we have reported are in line with those reported in previous series, and maintenance of radiographic parameters at final follow-up indicates that this osteotomy technique allows for solid fusion constructs.

The outrigger technique for controlling PSO closure is an effective method that simplifies instrumentation during a complex revision case.

Pedicle subtraction osteotomies (PSOs) have been used in the treatment of multiple spinal conditions involving a fixed sagittal imbalance, such as degenerative scoliosis, idiopathic scoliosis, posttraumatic deformities, iatrogenic flatback syndrome, and ankylosing spondylitis. The procedure was first described by Thomasen¹ for the treatment of ankylosing spondylitis. More recently, multiple centers have reported the expanded use and good success of PSO in the treatment of fixed sagittal imbalance of other etiologies.^2,3 According to Bridwell and colleagues,² lumbar lordosis can be increased 34.1°, and sagittal plumb line can be improved 13.5 cm.

PSO is a complex, extensive surgery most often performed in the revision setting. Multiple authors have described the technique for PSO.^4,5 There are significant technical challenges and many complications, including neurologic deficits, pseudarthrosis of adjacent levels, and wound infections.⁶ Short-term challenges include a large loss of blood, 2.4 L on average, according to Bridwell and colleagues.⁶ Time of closure of the osteotomy gap is a crucial point in the surgery. Blood loss, often large, slows only after the gap is closed and stabilized.

In this article, we describe a technique in which an additional rod or pedicle screw construct is used at the periosteotomy levels to close the osteotomy gap during PSO and simplify subsequent instrumentation. In addition, we report our experience with the procedure.

Materials and Methods

Seventeen consecutive patients (mean age, 58 years; range, 12-81 years) with fixed sagittal imbalance were treated with lumbar PSO. The indication in all cases was flatback syndrome after previous spinal surgery. Mean follow-up was 13 months. Mean number of prior surgeries was 3. Thirteen PSOs were performed at L3, and 4 were performed at L2.

Radiographic data were collected from before surgery, in the immediate postoperative period, and at final follow-up. All the radiographs were standing films. Established radiographic parameters were measured: thoracic kyphosis from T5 to T12, lumbar lordosis from L1 to S1, PSO angle (1 level above to 1 level below osteotomy level), sagittal plumb line (from center of C7 body to posterosuperior aspect of S1 body), and coronal plumb line (from center of C7 body to center of S1 body).²

Good clinical outcomes in the treatment of spinal disorders require careful attention to the alignment of the spine in the sagittal plane.^7,8 When evaluating the preoperative radiographs, we measured and documented pelvic parameters. Figure 1A shows how pelvic incidence was determined. We measured this as the angle between a line drawn from the center of the S1 endplate to the center of the femoral head and the perpendicular off the S1 endplate. Figure 1B shows pelvic tilt as determined by the angle between a line drawn from the center of S1 to the femoral head and a vertical line originating from the center of the femoral head. Figure 1C shows the sacral slope, which we measured as the angle between a line drawn parallel to the endplate of S1 and its intersection with a horizontal line.

Surgical Technique

The overall surgical technique for PSO has been well described.^4,5 Here we describe the “outrigger” modification to osteotomy closure (Figures 2, 3).

Most of our 17 cases were revisions. In these cases, new fixation points are first established. All fixation points that will be needed for the final fusion are placed. If a pedicle above or below the osteotomy level is not suitable for a screw, it can be skipped.

Wide decompression of the involved level is performed from pedicle to pedicle, ensuring that the nerve roots are completely decompressed. The dissection is then continued around the lateral wall of the vertebral body. While the neural elements are protected with gentle retraction, the pedicle and a portion of the posterior aspect of the vertebral body are removed with a combination of a rongeur and reverse-angle curettes. Resection of the vertebral body can be facilitated by attaching a short rod to the pedicle screws on either side of the osteotomy level and using it to provide gentle distraction.

Once sufficient bone has been removed to close the osteotomy, short rods are placed in the pedicle screws in the level above and the level below the osteotomy site. These rods are attached with offset connectors that allow the rods to be placed lateral to the screws. Before the surgical procedure is started, the patient is positioned on 2 sets of posts separated by the break in the table. The break in the table allows flexion to accommodate the preoperative kyphosis and allows hyperextension to help close the osteotomy site. Now, with the osteotomy site ready for closure, the table is gradually positioned in extension along with a combination of posterior pressure and compression between the pedicle screws above and below the osteotomy. Once the osteotomy is adequately compressed, the short rods are tightened, holding the osteotomy in good position. With the osteotomy held by the short rods and table positioning, decompression of the neural elements is confirmed and hemostasis obtained.

Final instrumentation is then performed with long rods that can bypass the osteotomized levels, allowing for simpler contouring. If desired, a cross connector can be placed between the long rod of the fusion construct and the short rod holding the osteotomy. The rest of the fusion procedure is completed in standard fashion with at least 1 subfascial drain.

Results

Our 17 patients’ results are summarized in the Table. Mean sagittal plumb line improved from 17.7 cm (range, 5.9 to 29 cm) before surgery to 4.5 cm (range, –0.2 to 12.9 cm) after surgery, for a mean improvement of 13.2 cm. At final follow-up, mean sagittal plumb line was 5.1 cm (range, –1.4 to 10.2 cm).

Mean lumbar lordosis improved from 10° (range, –14° to 34°) before surgery to 49° (range, 36° to 63°) after surgery, for a mean improvement of 39°. Mean PSO angle improved from 3° (range, –36° to 23°) before surgery to 41° (range, 25° to 65°) after surgery, for a mean improvement of 38°. At final follow-up, mean lumbar lordosis remained at 47° (range, 26° to 64°), and mean PSO angle was 39° (range, 24° to 59°).

Mean thoracic kyphosis improved from 18° (range, –8° to 52°) before surgery to 30° (range, 3° to 58°) after surgery, for a mean improvement of 12°. At final follow-up, mean thoracic kyphosis was 31° (range, 2° to 57°).

Fourteen patients did not have complications during the study period. Of the 3 patients with complications, 1 had an early infection, treated effectively with irrigation and débridement and intravenous antibiotics; 1 had a late deep infection, treated with multiple débridements, hardware removal, and, eventually, suppressive antibiotics; and 1 had cauda equina syndrome (caused by extensive scar tissue on the dura, which buckled with restoration of lordosis leading to cord compression), treated with duraplasty, which resulted in full neurologic recovery.

Discussion

In the present series of patients, the described technique for facilitating PSO for correction of sagittal imbalance was effective, and complications were similar to those previously reported.

The benefit of the outrigger construct is that it allows controlled compression of the osteotomy site and can be left in place at time of final instrumentation, locking in compression and correction. Other techniques involve removing the temporary rod and replacing it with final instrumentation^4,5—an extra step that complicates instrumentation of the additional levels of the fusion construct and possibly adds pedicle screw stress and contributes to loosening when the new rod is reduced to the pedicle screw. The final long rod construct can bypass the osteotomy levels and allow for simpler instrumentation.

 Mean age was 58 years in this series versus 52.4 years in the series reported by Bridwell and colleagues.² Given the higher mean age of our patients, though no objective measures of bone quality were available, this technique is likely applicable to patients with poor bone quality.

The complications we have reported are in line with those reported in previous series, and maintenance of radiographic parameters at final follow-up indicates that this osteotomy technique allows for solid fusion constructs.

The outrigger technique for controlling PSO closure is an effective method that simplifies instrumentation during a complex revision case.

Participating in a short series of phone conversations with trained counselors can substantially boost recovery and reduce pain in patients after spinal surgery, according to a study published online ahead of print March 28 in Archives of Physical Medicine and Rehabilitation.

The phone calls were designed to enhance standard pre- and post-operative care by reinforcing the value of continuing with physical therapy and back-strengthening exercise regimens.

“Phone counseling appears to be an easy, low-cost strategy that yields meaningful results by improving patient engagement in physical therapy and at-home exercise programs that are so vital for their recovery,” said lead study author Richard Skolasky Jr., ScD, Associate Professor of Orthopedic Surgery at the Johns Hopkins University School of Medicine in Baltimore.

The study included 122 patients ages 46 to 72, who underwent surgery at Johns Hopkins University between 2009 and 2012 to correct spinal stenosis. Each patient was assigned either home exercise programs or physical therapy to help accelerate their recovery time. About half of the patients also received a series of phone counseling sessions from a trained spinal surgery counselor to discuss the importance of exercise in their recovery. The first and most detailed phone session took place a few weeks before the patients had their surgeries. Two follow-up sessions occurred at 6 weeks and at 3 months after the operation was performed.

The study found that patients who received phone calls participated in physical therapy and home exercise at higher rates, and had less pain and less disability 6 months after their surgery, compared with the standard-approach group. Six months after surgery, 74% of patients who received phone counseling experienced significant improvements on standard measures of physical functioning and self-reported measures of pain, compared with 41% of people who did not receive phone calls.

“Modern orthopedic science has made great strides in surgical techniques to correct spinal deformities and achieved significant progress in developing physical therapies that boost the benefits of surgery, but we have not been all that good at motivating and engaging patients to partake in such post-surgical recovery programs,” said co-investigator Stephen Wegener, PhD, Associate Professor of Physical Medicine and Rehabilitation at Johns Hopkins University.

“The findings of our research suggest we may have found a way to add that missing ingredient that draws patients to be more active participants in their physical rehabilitation and recovery,” stated Dr. Wegener.

Participating in a short series of phone conversations with trained counselors can substantially boost recovery and reduce pain in patients after spinal surgery, according to a study published online ahead of print March 28 in Archives of Physical Medicine and Rehabilitation.

The phone calls were designed to enhance standard pre- and post-operative care by reinforcing the value of continuing with physical therapy and back-strengthening exercise regimens.

“Phone counseling appears to be an easy, low-cost strategy that yields meaningful results by improving patient engagement in physical therapy and at-home exercise programs that are so vital for their recovery,” said lead study author Richard Skolasky Jr., ScD, Associate Professor of Orthopedic Surgery at the Johns Hopkins University School of Medicine in Baltimore.

The study included 122 patients ages 46 to 72, who underwent surgery at Johns Hopkins University between 2009 and 2012 to correct spinal stenosis. Each patient was assigned either home exercise programs or physical therapy to help accelerate their recovery time. About half of the patients also received a series of phone counseling sessions from a trained spinal surgery counselor to discuss the importance of exercise in their recovery. The first and most detailed phone session took place a few weeks before the patients had their surgeries. Two follow-up sessions occurred at 6 weeks and at 3 months after the operation was performed.

The study found that patients who received phone calls participated in physical therapy and home exercise at higher rates, and had less pain and less disability 6 months after their surgery, compared with the standard-approach group. Six months after surgery, 74% of patients who received phone counseling experienced significant improvements on standard measures of physical functioning and self-reported measures of pain, compared with 41% of people who did not receive phone calls.

“Modern orthopedic science has made great strides in surgical techniques to correct spinal deformities and achieved significant progress in developing physical therapies that boost the benefits of surgery, but we have not been all that good at motivating and engaging patients to partake in such post-surgical recovery programs,” said co-investigator Stephen Wegener, PhD, Associate Professor of Physical Medicine and Rehabilitation at Johns Hopkins University.

“The findings of our research suggest we may have found a way to add that missing ingredient that draws patients to be more active participants in their physical rehabilitation and recovery,” stated Dr. Wegener.

Participating in a short series of phone conversations with trained counselors can substantially boost recovery and reduce pain in patients after spinal surgery, according to a study published online ahead of print March 28 in Archives of Physical Medicine and Rehabilitation.

The phone calls were designed to enhance standard pre- and post-operative care by reinforcing the value of continuing with physical therapy and back-strengthening exercise regimens.

“Phone counseling appears to be an easy, low-cost strategy that yields meaningful results by improving patient engagement in physical therapy and at-home exercise programs that are so vital for their recovery,” said lead study author Richard Skolasky Jr., ScD, Associate Professor of Orthopedic Surgery at the Johns Hopkins University School of Medicine in Baltimore.

The study included 122 patients ages 46 to 72, who underwent surgery at Johns Hopkins University between 2009 and 2012 to correct spinal stenosis. Each patient was assigned either home exercise programs or physical therapy to help accelerate their recovery time. About half of the patients also received a series of phone counseling sessions from a trained spinal surgery counselor to discuss the importance of exercise in their recovery. The first and most detailed phone session took place a few weeks before the patients had their surgeries. Two follow-up sessions occurred at 6 weeks and at 3 months after the operation was performed.

The study found that patients who received phone calls participated in physical therapy and home exercise at higher rates, and had less pain and less disability 6 months after their surgery, compared with the standard-approach group. Six months after surgery, 74% of patients who received phone counseling experienced significant improvements on standard measures of physical functioning and self-reported measures of pain, compared with 41% of people who did not receive phone calls.

“Modern orthopedic science has made great strides in surgical techniques to correct spinal deformities and achieved significant progress in developing physical therapies that boost the benefits of surgery, but we have not been all that good at motivating and engaging patients to partake in such post-surgical recovery programs,” said co-investigator Stephen Wegener, PhD, Associate Professor of Physical Medicine and Rehabilitation at Johns Hopkins University.

“The findings of our research suggest we may have found a way to add that missing ingredient that draws patients to be more active participants in their physical rehabilitation and recovery,” stated Dr. Wegener.

The Reamer/Irrigator/Aspirator (RIA) system (Synthes, West Chester, Pennsylvania) has become a powerful tool for harvesting autologous bone graft from the intramedullary canal of the long bones of the lower extremity for the treatment of osseous defects, nonunions, and joint fusions.^1,2 The RIA system provides satisfactory quality and quantity of bone graft (range, 40-90 mL)^3-5 with osteogenic properties that rival those harvested from the iliac crest.^6,7 Minimal donor-site morbidity and mortality have been reported in association with the RIA technique compared with iliac crest bone graft harvest.⁸

The RIA technique for the femur—with the antegrade approach and the supine position,⁸ with the antegrade approach and the prone position,⁹ and with the retrograde approach and the supine position⁴—has been described in the literature. To our knowledge, however, the RIA technique for the femur with the retrograde approach and the prone position has not been described. Antegrade harvesting uses the trochanteric entry point, and retrograde harvesting uses an entry at the intercondylar notch just anterior to the posterior cruciate ligament. In this article, we detail the technique for RIA harvesting of the femur with the patient in the prone position. Patient positioning is based on the diagnosis and the proposed procedure.

Advantages of a retrograde starting point include a more concentric trajectory (vs that of an antegrade starting point) and more efficient canal pressure reduction, which might decrease the risk of intraoperative fat embolization.¹⁰ This technique offers a more efficient solution to any procedure that requires the prone position, and it avoids the need to reposition, reprepare, or redrape the extremity. It is also very useful in treating obese patients.

After obtaining institutional review board (IRB) approval, we retrospectively reviewed patient files. Because the study was retrospective, the IRB waived the requirement for informed consent. The patients described here provided written informed consent for print and electronic publication of these case reports.

Surgical Technique

The patient is placed in a prone position on a radiolucent table with a bump under the thigh to allow access to the knee joint with full extension of the hip (Figures 1, 2A, 2B). The knee is then flexed to gain access to the intercondylar notch.

The anatomical axis of the femur is identified in the coronal and sagittal planes with the help of an image intensifier. Frequent intraoperative fluoroscopic imaging is required to prevent eccentric reaming and guide-wire movement from causing iatrogenic fractures and perforations, respectively.⁸ A 2-mm Steinmann pin is used to identify the point of entry into the femoral canal, which is located just above the posterior cruciate ligament insertion in the intercondylar notch, and care is taken not to ream this structure. A minimally invasive incision of about 15 mm is centered on this pin using a patellar tendon–splitting approach.

An 8-mm cannulated anterior cruciate ligament reamer is passed over the pin to enlarge the opening at the entry point, and a 2.5-mm ball-tipped guide wire is positioned in the femur. The image intensifier is used to confirm positioning of the guide in the trochanteric region and centered in the intramedullary canal. A radiolucent diving board facilitates fluoroscopic imaging.

The diameter (12.5 or 16.5 mm) of the reaming head is selected after the intramedullary guide is placed in the femoral canal. The isthmus of the femur is then identified radiographically, and a radiopaque ruler with increments in millimeters is used to measure the canal diameter (Figures 3A, 3B). Because the femoral canal is an ellipsoid, the canal diameter usually is much larger anteroposteriorly than laterally.⁸ We prefer to use a reaming head that overlaps the inner cortical diameter by 1 mm on each side. An alternative method includes measuring the outer diameter of the narrowest portion of the bone and using a reamer head no more than 45% of the outer diameter at the isthmus.⁸

The RIA system is prepared on the back table by attaching the reaming head to the irrigation and suction systems. As the reamer head enters the intramedullary canal, an approach–withdraw–pause technique is used to slowly advance the reamer through the femur. It is crucial to use the image intensifier to guide reaming in order to avoid overdrilling the anterior cortex and prevent eccentric reaming of the canal, which more commonly occurs in patients with large anterior femoral bows.¹¹ When the collection filter becomes full, reaming is stopped. The bone graft in the filter is emptied into a specimen cup for measurement and storage until subsequent use (Figure 4). Suctioning is suspended when reaming is stopped because substantial blood loss can occur with prolonged suction and aspiration.¹² When repeat reaming is required, care is taken not to overream the cortices, thereby avoiding the risk of iatrogenic fracture.^10,12

The knee joint is irrigated to remove any intramedullary debris. Typically there is no debris, as it is captured by the RIA. The wound is closed in 2 layers. Dressing with Ace bandage (3M, St. Paul, Minnesota) is placed around the knee for comfort. Weight-bearing status is determined by the index procedure.

Case Reports

Case 1

A 68-year-old female smoker presented to our facility with right ankle pain after recent ankle arthrodesis for pilon fracture nonunion. Almost 3 years earlier, the patient sustained a Gustilo-Anderson type II open pilon fracture in a motorcycle accident. She underwent antibiotic therapy, irrigation and débridement of the fracture site, and external fixation before definitive treatment with repeat irrigation and débridement and open reduction and internal fixation of the tibial plafond. About 6 months after surgery, she presented to her surgeon with a draining abscess over the anteromedial surgical incision. Multiple débridement procedures were performed, the implant was removed, the ankle was stabilized with a bridging external fixator, and culture-specific antibiotic therapy was administered. Intraoperative cultures confirmed methicillin-resistant Staphylococcus aureus. Vancomycin was administered intravenously for 6 weeks. Once C-reactive protein level and erythrocyte sedimentation rate returned to normal, repeat débridement with a rectus abdominis free flap and ankle fusion were performed.

When the patient presented to our clinic, we saw atrophic nonunion of the ankle fusion on radiographs. Smoking cessation was encouraged but not required before surgery. The patient returned to the operating suite for tibiotalocalcaneal fusion with a retrograde intramedullary nail. With the patient in the prone position, retrograde femoral RIA reaming was performed to harvest 30 mL of autologous bone. After resection of the nonunion site using a trans-Achilles approach and insertion of the intramedullary nail, the autologous bone graft was mixed with recombinant human bone morphogenetic protein 2 (BMP-2), and the mixture was introduced into the fusion site. At final follow-up, 18 months after surgery, the patient was clinically asymptomatic and radiographically healed—without further intervention and despite continued smoking. She did not report any knee pain from the harvest site.

Case 2

A 59-year-old noncompliant woman with diabetes and Charcot neuropathy sustained a trimalleolar ankle fracture-dislocation that was initially treated with ankle and hindfoot arthrodesis. The postoperative course was uneventful, and she was discharged home. Less than a week later, she presented to the emergency department with a midshaft tibial fracture just proximal to the ankle and hindfoot fusion nail. She subsequently had the device removed and a long arthrodesis rod inserted to span the fracture site up to the proximal tibial metadiaphysis. About 9 months later, she returned to our office complaining of ankle pain. No signs of infection were clinically evident. Radiographs showed nonunion of the ankle and subtalar joint. Findings of the initial bone biopsy and pathologic examination were negative for infection. The patient returned to the operating room 4 weeks later for revision ankle fusion. With the patient in the prone position, autologous bone (~30 mL) was harvested using retrograde femoral RIA reaming. The nonunion site was resected, and a mixture of autologous bone graft and BMP-2 was applied. Through a posterior approach, an anterior ankle arthrodesis locking plate was applied to the posterior aspect of the calcaneus and tibia. The patient was kept non-weight-bearing for 3 months and progressed in weight-bearing for another 4 to 6 weeks. Ambulatory status was restored about 4 months after surgery. No harvest-site knee pain was reported.

Discussion

Given its osteogenic, osteoconductive, and osteoinductive properties, autologous cancellous bone graft is the gold standard for reconstruction and fusion procedures in foot and ankle surgery.¹³ Bone graft can be obtained from many potential donor sites, but the most common is the iliac crest.² However, many comorbidities, such as residual donor-site pain, neurovascular injuries, infection, and increased surgical time, have been reported in the literature.^14,15 The RIA system was initially developed for simultaneous reaming and aspiration to reduce intramedullary pressure, heat generation, operating time, and the systemic effects of reaming, such as the embolic phenomenon.^16-22 The single-pass reamer has provided a minimally invasive strategy for procuring voluminous amounts of autologous cancellous bone from the intramedullary canal of lower extremity long bones. Schmidmaier and colleagues³ recently quantified the measurements of several growth factors, such as insulinlike growth factor 1, transforming growth factor β 1, and BMP-2—proving that RIA-derived aspirates have amounts comparable to if not larger than those of iliac crest autologous bone graft. Pratt and colleagues²³ provided insight into the possibility of induction of mesenchymal stem cells using the previously unwanted supernatant reamings after filtration. Recently, the RIA technique of autologous tibial and hindfoot bone graft harvest was described for use in ankle or tibiotalocalcaneal arthrodesis.² Although this technique is a useful surgical option, tibia size remains a limiting factor. Kovar and Wozasek²⁴ reported harvesting significantly more bone graft in the femur than in the tibia. A tibia that cannot accommodate the 12-mm (smallest) reamer head in the RIA system would be a contraindication. In addition, concerns about the association between tibial stress fractures and reaming of the entire tibial canal and concerns about the overall donor-site morbidity of the tibial shaft remain.

Conclusion

With its retrograde approach and prone positioning, this RIA technique is an effective and efficient solution for harvesting autologous femoral bone graft. Although we have described its use in ankle and hindfoot arthrodesis, this technique can be applied to any prone-position surgical procedure, including spine surgery.

The Reamer/Irrigator/Aspirator (RIA) system (Synthes, West Chester, Pennsylvania) has become a powerful tool for harvesting autologous bone graft from the intramedullary canal of the long bones of the lower extremity for the treatment of osseous defects, nonunions, and joint fusions.^1,2 The RIA system provides satisfactory quality and quantity of bone graft (range, 40-90 mL)^3-5 with osteogenic properties that rival those harvested from the iliac crest.^6,7 Minimal donor-site morbidity and mortality have been reported in association with the RIA technique compared with iliac crest bone graft harvest.⁸

The RIA technique for the femur—with the antegrade approach and the supine position,⁸ with the antegrade approach and the prone position,⁹ and with the retrograde approach and the supine position⁴—has been described in the literature. To our knowledge, however, the RIA technique for the femur with the retrograde approach and the prone position has not been described. Antegrade harvesting uses the trochanteric entry point, and retrograde harvesting uses an entry at the intercondylar notch just anterior to the posterior cruciate ligament. In this article, we detail the technique for RIA harvesting of the femur with the patient in the prone position. Patient positioning is based on the diagnosis and the proposed procedure.

Advantages of a retrograde starting point include a more concentric trajectory (vs that of an antegrade starting point) and more efficient canal pressure reduction, which might decrease the risk of intraoperative fat embolization.¹⁰ This technique offers a more efficient solution to any procedure that requires the prone position, and it avoids the need to reposition, reprepare, or redrape the extremity. It is also very useful in treating obese patients.

After obtaining institutional review board (IRB) approval, we retrospectively reviewed patient files. Because the study was retrospective, the IRB waived the requirement for informed consent. The patients described here provided written informed consent for print and electronic publication of these case reports.

Surgical Technique

The patient is placed in a prone position on a radiolucent table with a bump under the thigh to allow access to the knee joint with full extension of the hip (Figures 1, 2A, 2B). The knee is then flexed to gain access to the intercondylar notch.

The anatomical axis of the femur is identified in the coronal and sagittal planes with the help of an image intensifier. Frequent intraoperative fluoroscopic imaging is required to prevent eccentric reaming and guide-wire movement from causing iatrogenic fractures and perforations, respectively.⁸ A 2-mm Steinmann pin is used to identify the point of entry into the femoral canal, which is located just above the posterior cruciate ligament insertion in the intercondylar notch, and care is taken not to ream this structure. A minimally invasive incision of about 15 mm is centered on this pin using a patellar tendon–splitting approach.

An 8-mm cannulated anterior cruciate ligament reamer is passed over the pin to enlarge the opening at the entry point, and a 2.5-mm ball-tipped guide wire is positioned in the femur. The image intensifier is used to confirm positioning of the guide in the trochanteric region and centered in the intramedullary canal. A radiolucent diving board facilitates fluoroscopic imaging.

The diameter (12.5 or 16.5 mm) of the reaming head is selected after the intramedullary guide is placed in the femoral canal. The isthmus of the femur is then identified radiographically, and a radiopaque ruler with increments in millimeters is used to measure the canal diameter (Figures 3A, 3B). Because the femoral canal is an ellipsoid, the canal diameter usually is much larger anteroposteriorly than laterally.⁸ We prefer to use a reaming head that overlaps the inner cortical diameter by 1 mm on each side. An alternative method includes measuring the outer diameter of the narrowest portion of the bone and using a reamer head no more than 45% of the outer diameter at the isthmus.⁸

The RIA system is prepared on the back table by attaching the reaming head to the irrigation and suction systems. As the reamer head enters the intramedullary canal, an approach–withdraw–pause technique is used to slowly advance the reamer through the femur. It is crucial to use the image intensifier to guide reaming in order to avoid overdrilling the anterior cortex and prevent eccentric reaming of the canal, which more commonly occurs in patients with large anterior femoral bows.¹¹ When the collection filter becomes full, reaming is stopped. The bone graft in the filter is emptied into a specimen cup for measurement and storage until subsequent use (Figure 4). Suctioning is suspended when reaming is stopped because substantial blood loss can occur with prolonged suction and aspiration.¹² When repeat reaming is required, care is taken not to overream the cortices, thereby avoiding the risk of iatrogenic fracture.^10,12

The knee joint is irrigated to remove any intramedullary debris. Typically there is no debris, as it is captured by the RIA. The wound is closed in 2 layers. Dressing with Ace bandage (3M, St. Paul, Minnesota) is placed around the knee for comfort. Weight-bearing status is determined by the index procedure.

Case Reports

Case 1

A 68-year-old female smoker presented to our facility with right ankle pain after recent ankle arthrodesis for pilon fracture nonunion. Almost 3 years earlier, the patient sustained a Gustilo-Anderson type II open pilon fracture in a motorcycle accident. She underwent antibiotic therapy, irrigation and débridement of the fracture site, and external fixation before definitive treatment with repeat irrigation and débridement and open reduction and internal fixation of the tibial plafond. About 6 months after surgery, she presented to her surgeon with a draining abscess over the anteromedial surgical incision. Multiple débridement procedures were performed, the implant was removed, the ankle was stabilized with a bridging external fixator, and culture-specific antibiotic therapy was administered. Intraoperative cultures confirmed methicillin-resistant Staphylococcus aureus. Vancomycin was administered intravenously for 6 weeks. Once C-reactive protein level and erythrocyte sedimentation rate returned to normal, repeat débridement with a rectus abdominis free flap and ankle fusion were performed.

When the patient presented to our clinic, we saw atrophic nonunion of the ankle fusion on radiographs. Smoking cessation was encouraged but not required before surgery. The patient returned to the operating suite for tibiotalocalcaneal fusion with a retrograde intramedullary nail. With the patient in the prone position, retrograde femoral RIA reaming was performed to harvest 30 mL of autologous bone. After resection of the nonunion site using a trans-Achilles approach and insertion of the intramedullary nail, the autologous bone graft was mixed with recombinant human bone morphogenetic protein 2 (BMP-2), and the mixture was introduced into the fusion site. At final follow-up, 18 months after surgery, the patient was clinically asymptomatic and radiographically healed—without further intervention and despite continued smoking. She did not report any knee pain from the harvest site.

Case 2

A 59-year-old noncompliant woman with diabetes and Charcot neuropathy sustained a trimalleolar ankle fracture-dislocation that was initially treated with ankle and hindfoot arthrodesis. The postoperative course was uneventful, and she was discharged home. Less than a week later, she presented to the emergency department with a midshaft tibial fracture just proximal to the ankle and hindfoot fusion nail. She subsequently had the device removed and a long arthrodesis rod inserted to span the fracture site up to the proximal tibial metadiaphysis. About 9 months later, she returned to our office complaining of ankle pain. No signs of infection were clinically evident. Radiographs showed nonunion of the ankle and subtalar joint. Findings of the initial bone biopsy and pathologic examination were negative for infection. The patient returned to the operating room 4 weeks later for revision ankle fusion. With the patient in the prone position, autologous bone (~30 mL) was harvested using retrograde femoral RIA reaming. The nonunion site was resected, and a mixture of autologous bone graft and BMP-2 was applied. Through a posterior approach, an anterior ankle arthrodesis locking plate was applied to the posterior aspect of the calcaneus and tibia. The patient was kept non-weight-bearing for 3 months and progressed in weight-bearing for another 4 to 6 weeks. Ambulatory status was restored about 4 months after surgery. No harvest-site knee pain was reported.

Discussion

Given its osteogenic, osteoconductive, and osteoinductive properties, autologous cancellous bone graft is the gold standard for reconstruction and fusion procedures in foot and ankle surgery.¹³ Bone graft can be obtained from many potential donor sites, but the most common is the iliac crest.² However, many comorbidities, such as residual donor-site pain, neurovascular injuries, infection, and increased surgical time, have been reported in the literature.^14,15 The RIA system was initially developed for simultaneous reaming and aspiration to reduce intramedullary pressure, heat generation, operating time, and the systemic effects of reaming, such as the embolic phenomenon.^16-22 The single-pass reamer has provided a minimally invasive strategy for procuring voluminous amounts of autologous cancellous bone from the intramedullary canal of lower extremity long bones. Schmidmaier and colleagues³ recently quantified the measurements of several growth factors, such as insulinlike growth factor 1, transforming growth factor β 1, and BMP-2—proving that RIA-derived aspirates have amounts comparable to if not larger than those of iliac crest autologous bone graft. Pratt and colleagues²³ provided insight into the possibility of induction of mesenchymal stem cells using the previously unwanted supernatant reamings after filtration. Recently, the RIA technique of autologous tibial and hindfoot bone graft harvest was described for use in ankle or tibiotalocalcaneal arthrodesis.² Although this technique is a useful surgical option, tibia size remains a limiting factor. Kovar and Wozasek²⁴ reported harvesting significantly more bone graft in the femur than in the tibia. A tibia that cannot accommodate the 12-mm (smallest) reamer head in the RIA system would be a contraindication. In addition, concerns about the association between tibial stress fractures and reaming of the entire tibial canal and concerns about the overall donor-site morbidity of the tibial shaft remain.

Conclusion

With its retrograde approach and prone positioning, this RIA technique is an effective and efficient solution for harvesting autologous femoral bone graft. Although we have described its use in ankle and hindfoot arthrodesis, this technique can be applied to any prone-position surgical procedure, including spine surgery.

The Reamer/Irrigator/Aspirator (RIA) system (Synthes, West Chester, Pennsylvania) has become a powerful tool for harvesting autologous bone graft from the intramedullary canal of the long bones of the lower extremity for the treatment of osseous defects, nonunions, and joint fusions.^1,2 The RIA system provides satisfactory quality and quantity of bone graft (range, 40-90 mL)^3-5 with osteogenic properties that rival those harvested from the iliac crest.^6,7 Minimal donor-site morbidity and mortality have been reported in association with the RIA technique compared with iliac crest bone graft harvest.⁸

The RIA technique for the femur—with the antegrade approach and the supine position,⁸ with the antegrade approach and the prone position,⁹ and with the retrograde approach and the supine position⁴—has been described in the literature. To our knowledge, however, the RIA technique for the femur with the retrograde approach and the prone position has not been described. Antegrade harvesting uses the trochanteric entry point, and retrograde harvesting uses an entry at the intercondylar notch just anterior to the posterior cruciate ligament. In this article, we detail the technique for RIA harvesting of the femur with the patient in the prone position. Patient positioning is based on the diagnosis and the proposed procedure.

Advantages of a retrograde starting point include a more concentric trajectory (vs that of an antegrade starting point) and more efficient canal pressure reduction, which might decrease the risk of intraoperative fat embolization.¹⁰ This technique offers a more efficient solution to any procedure that requires the prone position, and it avoids the need to reposition, reprepare, or redrape the extremity. It is also very useful in treating obese patients.

After obtaining institutional review board (IRB) approval, we retrospectively reviewed patient files. Because the study was retrospective, the IRB waived the requirement for informed consent. The patients described here provided written informed consent for print and electronic publication of these case reports.

Surgical Technique

The patient is placed in a prone position on a radiolucent table with a bump under the thigh to allow access to the knee joint with full extension of the hip (Figures 1, 2A, 2B). The knee is then flexed to gain access to the intercondylar notch.

The anatomical axis of the femur is identified in the coronal and sagittal planes with the help of an image intensifier. Frequent intraoperative fluoroscopic imaging is required to prevent eccentric reaming and guide-wire movement from causing iatrogenic fractures and perforations, respectively.⁸ A 2-mm Steinmann pin is used to identify the point of entry into the femoral canal, which is located just above the posterior cruciate ligament insertion in the intercondylar notch, and care is taken not to ream this structure. A minimally invasive incision of about 15 mm is centered on this pin using a patellar tendon–splitting approach.

An 8-mm cannulated anterior cruciate ligament reamer is passed over the pin to enlarge the opening at the entry point, and a 2.5-mm ball-tipped guide wire is positioned in the femur. The image intensifier is used to confirm positioning of the guide in the trochanteric region and centered in the intramedullary canal. A radiolucent diving board facilitates fluoroscopic imaging.

The diameter (12.5 or 16.5 mm) of the reaming head is selected after the intramedullary guide is placed in the femoral canal. The isthmus of the femur is then identified radiographically, and a radiopaque ruler with increments in millimeters is used to measure the canal diameter (Figures 3A, 3B). Because the femoral canal is an ellipsoid, the canal diameter usually is much larger anteroposteriorly than laterally.⁸ We prefer to use a reaming head that overlaps the inner cortical diameter by 1 mm on each side. An alternative method includes measuring the outer diameter of the narrowest portion of the bone and using a reamer head no more than 45% of the outer diameter at the isthmus.⁸

The RIA system is prepared on the back table by attaching the reaming head to the irrigation and suction systems. As the reamer head enters the intramedullary canal, an approach–withdraw–pause technique is used to slowly advance the reamer through the femur. It is crucial to use the image intensifier to guide reaming in order to avoid overdrilling the anterior cortex and prevent eccentric reaming of the canal, which more commonly occurs in patients with large anterior femoral bows.¹¹ When the collection filter becomes full, reaming is stopped. The bone graft in the filter is emptied into a specimen cup for measurement and storage until subsequent use (Figure 4). Suctioning is suspended when reaming is stopped because substantial blood loss can occur with prolonged suction and aspiration.¹² When repeat reaming is required, care is taken not to overream the cortices, thereby avoiding the risk of iatrogenic fracture.^10,12

The knee joint is irrigated to remove any intramedullary debris. Typically there is no debris, as it is captured by the RIA. The wound is closed in 2 layers. Dressing with Ace bandage (3M, St. Paul, Minnesota) is placed around the knee for comfort. Weight-bearing status is determined by the index procedure.

Case Reports

Case 1

A 68-year-old female smoker presented to our facility with right ankle pain after recent ankle arthrodesis for pilon fracture nonunion. Almost 3 years earlier, the patient sustained a Gustilo-Anderson type II open pilon fracture in a motorcycle accident. She underwent antibiotic therapy, irrigation and débridement of the fracture site, and external fixation before definitive treatment with repeat irrigation and débridement and open reduction and internal fixation of the tibial plafond. About 6 months after surgery, she presented to her surgeon with a draining abscess over the anteromedial surgical incision. Multiple débridement procedures were performed, the implant was removed, the ankle was stabilized with a bridging external fixator, and culture-specific antibiotic therapy was administered. Intraoperative cultures confirmed methicillin-resistant Staphylococcus aureus. Vancomycin was administered intravenously for 6 weeks. Once C-reactive protein level and erythrocyte sedimentation rate returned to normal, repeat débridement with a rectus abdominis free flap and ankle fusion were performed.

When the patient presented to our clinic, we saw atrophic nonunion of the ankle fusion on radiographs. Smoking cessation was encouraged but not required before surgery. The patient returned to the operating suite for tibiotalocalcaneal fusion with a retrograde intramedullary nail. With the patient in the prone position, retrograde femoral RIA reaming was performed to harvest 30 mL of autologous bone. After resection of the nonunion site using a trans-Achilles approach and insertion of the intramedullary nail, the autologous bone graft was mixed with recombinant human bone morphogenetic protein 2 (BMP-2), and the mixture was introduced into the fusion site. At final follow-up, 18 months after surgery, the patient was clinically asymptomatic and radiographically healed—without further intervention and despite continued smoking. She did not report any knee pain from the harvest site.

Case 2

A 59-year-old noncompliant woman with diabetes and Charcot neuropathy sustained a trimalleolar ankle fracture-dislocation that was initially treated with ankle and hindfoot arthrodesis. The postoperative course was uneventful, and she was discharged home. Less than a week later, she presented to the emergency department with a midshaft tibial fracture just proximal to the ankle and hindfoot fusion nail. She subsequently had the device removed and a long arthrodesis rod inserted to span the fracture site up to the proximal tibial metadiaphysis. About 9 months later, she returned to our office complaining of ankle pain. No signs of infection were clinically evident. Radiographs showed nonunion of the ankle and subtalar joint. Findings of the initial bone biopsy and pathologic examination were negative for infection. The patient returned to the operating room 4 weeks later for revision ankle fusion. With the patient in the prone position, autologous bone (~30 mL) was harvested using retrograde femoral RIA reaming. The nonunion site was resected, and a mixture of autologous bone graft and BMP-2 was applied. Through a posterior approach, an anterior ankle arthrodesis locking plate was applied to the posterior aspect of the calcaneus and tibia. The patient was kept non-weight-bearing for 3 months and progressed in weight-bearing for another 4 to 6 weeks. Ambulatory status was restored about 4 months after surgery. No harvest-site knee pain was reported.

Discussion

Given its osteogenic, osteoconductive, and osteoinductive properties, autologous cancellous bone graft is the gold standard for reconstruction and fusion procedures in foot and ankle surgery.¹³ Bone graft can be obtained from many potential donor sites, but the most common is the iliac crest.² However, many comorbidities, such as residual donor-site pain, neurovascular injuries, infection, and increased surgical time, have been reported in the literature.^14,15 The RIA system was initially developed for simultaneous reaming and aspiration to reduce intramedullary pressure, heat generation, operating time, and the systemic effects of reaming, such as the embolic phenomenon.^16-22 The single-pass reamer has provided a minimally invasive strategy for procuring voluminous amounts of autologous cancellous bone from the intramedullary canal of lower extremity long bones. Schmidmaier and colleagues³ recently quantified the measurements of several growth factors, such as insulinlike growth factor 1, transforming growth factor β 1, and BMP-2—proving that RIA-derived aspirates have amounts comparable to if not larger than those of iliac crest autologous bone graft. Pratt and colleagues²³ provided insight into the possibility of induction of mesenchymal stem cells using the previously unwanted supernatant reamings after filtration. Recently, the RIA technique of autologous tibial and hindfoot bone graft harvest was described for use in ankle or tibiotalocalcaneal arthrodesis.² Although this technique is a useful surgical option, tibia size remains a limiting factor. Kovar and Wozasek²⁴ reported harvesting significantly more bone graft in the femur than in the tibia. A tibia that cannot accommodate the 12-mm (smallest) reamer head in the RIA system would be a contraindication. In addition, concerns about the association between tibial stress fractures and reaming of the entire tibial canal and concerns about the overall donor-site morbidity of the tibial shaft remain.

Conclusion

With its retrograde approach and prone positioning, this RIA technique is an effective and efficient solution for harvesting autologous femoral bone graft. Although we have described its use in ankle and hindfoot arthrodesis, this technique can be applied to any prone-position surgical procedure, including spine surgery.

Osteoarthritis is the most common joint disorder, resulting in significant morbidity and disability. The worldwide prevalence of osteoarthritis was estimated at more than 151 million people, according to data published in 2004.¹ In the United States, almost 27 million adults age 25 years and older suffer from clinically apparent disease.² The spine is one of the most commonly affected joints of arthritis, and idiopathic low back pain is the most frequent complaint in the adult population.³ In adults with low back pain, evidence of lumbar intervertebral disc degeneration is often found on radiography.⁴ In 1 study, evidence of disc degeneration was found in 90% of adults age 50 to 59 years.⁵

Degenerative spinal disease most commonly affects the lumbar spine due to its high degree of mobility and weight-loading.^6,7 Clinical^8,9 and experimental studies¹⁰ have suggested that the degenerative changes in the lumbar spine begin in the intervertebral discs. Degenerative disc disease (DDD) results from a continuum of dehydration, degradation, and remodeling of the intervertebral discs and neighboring vertebrae to accommodate the changes in physical loading.^11-13 This results in disc-space narrowing, disc bulging and herniation, vertebral rim osteophyte formation, and endplate sclerosis.^7,14 Symptomatic neural compression may occur, often manifested by localized lower back and extremity pain, as well as sensory loss and weakness of the lower extremities.^15-17 Changes in posture and gait may result because of altered sensation, and the consequent abnormal force transmission may predispose joints to accelerated wear and arthrosis.^15,18

Numerous studies have delineated the association between lumbar spinal disorders and lower extremity arthrosis. Of note, research has demonstrated that hip and/or knee pathology and gait alteration may promote low back pain and lumbar disc degeneration.^19-21 Although spinal abnormalities, such as scoliosis, may predispose an individual to accelerated hip degeneration,²⁰ no studies have investigated the relationship between lumbar DDD and ankle osteoarthritis.

Ankle arthritis differs from hip and knee arthritis demographically, occurring approximately 9 times less frequently.²¹ The ankle joint is subjected to more weight-bearing force per square centimeter and is more commonly injured than any other joint in the body.²¹ Trauma and/or abnormal ankle mechanics are the most common causes of degenerative ankle arthritis.²² Other potential causes include inflammatory arthropathies, neuropathic arthropathy, infection, and tumor. The purpose of this study was to determine if a relationship exists between ankle arthrosis and lumbar disc degeneration, and to delineate if one may promote the onset or progression of the other.

Materials and Methods

We randomly chose 710 cadaveric specimens from the Hamann-Todd Osteological Collection in Cleveland, Ohio. The Hamann-Todd Collection contains skeletal remains from more than 3000 individuals who died in Cleveland, Ohio between 1893 and 1938. The cohort for this study included 583 male and 127 female cadavers, ranging in age from 17 to 105 years at the time of death. Table 1 shows the breakdown of these specimens according to age group; of the 710 specimens, 306 were of African American ancestry, and 404 were Caucasian.

Lumbar DDD was graded at each lumbar spinal level by a single examiner using the Eubanks modification²³ of the Kettler and Wilke classification of vertebral endplate osteophytosis²⁴:

Grade 0: normal vertebral endplates;

Grade 1: mild arthrosis, with evidence of osteophytic reaction involving up to 50% of the vertebral endplates;

Grade 2: moderate arthrosis, with evidence of osteophytic reaction involving 50% to 100% of the vertebral endplates;

Grade 3: severe arthrosis, with evidence of osteophytic reaction involving 100% of the vertebral endplates. Osteophytes are hypertrophic and bridging the joint space (Figure 1);

Grade 4: complete ankylosis. 

Tibiotalar joint osteoarthritis was evaluated by a single examiner using a modification of the Kellgren-Lawrence classification⁴ for knee osteoarthritis:

Grade 0: no discernable wear/osteophytes;

Grade 1: 1-mm osteophyte(s) and/or <25% surface wear;

Grade 2: 1- to 2-mm osteophyte(s) and/or 25% to 50% joint surface;

Grade 3: 2- to 3-mm osteophyte(s) and/or >50% joint surface (Figure 2);

Grade 4: multiple large osteophytes and/or definite bony end deformity.

Statistical analysis was performed on the compiled data using Stata software (StataCorp, College Station, Texas). Linear and logistic regression analyses correcting for confounding factors of age, sex, race, and height were performed using a standard P-value cutoff (P < .05) and 95% confidence interval to determine statistical significance.

Results         

Patients were considered to have osteoarthritis of the tibiotalar joint if either of the extremities measured grade 1 or higher. Of the 710 specimens selected, 14 specimens did not have adequate bone available for bilateral tibiotalar joint measurement, either from extensive bone degradation or amputation. Of the remaining 696 specimens, 586 had some degree of tibiotalar osteoarthritis present (Table 2). Regression analysis showed a significant positive association between right- and left-ankle osteoarthritis (coefficient: 0.491, P < .01). Tibiotalar joint arthritis was classified as severe if either extremity had arthrosis of grade 3 or higher. Of the 586 specimens that had tibiotalar joint arthritis, only 16% (97 specimens) had severe tibiotalar joint arthritis.

Data regarding lumbar disc degeneration were available for 516 of the 710 specimens selected, 443 of which showed some disc degeneration. Disc degeneration was most prevalent and significant at the L4-L5 and L3-L4 intervertebral levels (Figures 3, 4). Of these 516 specimens, 30 had degeneration at 1 level, 47 specimens had degeneration at 2 levels, 29 specimens had degeneration at 3 levels, 52 had degeneration at 4 levels, and 285 specimens had degeneration at all 5 lumbar levels. The majority of specimens were found to have some degree of degeneration at all 5 lumbar spinal levels (Figure 5). Severe lumbar DDD was defined as grade 3 or higher osteoarthritis present in at least 1 of the 5 lumbar levels. Of the 516 specimens that showed some degree of disc degeneration, 152 were classified as severe. When stratified by number of spinal levels, only 30% of specimens were found to have evidence of severe arthrosis, the majority of which was located at only 1 lumbar segment (Figure 6).

Linear regression analysis of the data showed a statistically significant positive association between lumbar disc degeneration and tibiotalar osteoarthritis (coefficient: 0.844, P < .01), even when correcting for confounding factors, such as age, sex, and race (coefficient: 0.331, P < .01).

Additional analysis of the data demonstrated that tibiotalar joint arthritis remained significantly associated with lumbar DDD across each lumbar level: L1-L2 (coefficient: 0.269, P < .01), L2-L3 (coefficient: 0.283, P < .01), L3-L4 (coefficient: 0.299, P < .01), L4-L5 (coefficient: 0.240, P < .02), L5-S1 (coefficient: 0.167, P < .05).

The presence of 3 or more levels of lumbar DDD significantly increased the possibility of developing severe tibiotalar joint arthritis. Lumbar DDD that encompassed 3 levels showed the highest odds for development of severe tibiotalar joint arthritis with an odds ratio (OR) of 20.542 (Table 3).

When subjects were compared by decade, the mean grade of tibiotalar joint arthritis was significantly higher than lumbar DDD in specimens who died in their 20s and 30s. This difference was insignificant in the fourth decade, and thereafter the mean value of lumbar DDD surpassed that of tibiotalar joint arthritis (Figure 7).

In contrast, severe lumbar DDD was more prevalent than severe tibiotalar joint arthritis in individuals age 20 years or older (Figure 8). There were no specimens under age 20 years with severe lumbar DDD or severe tibiotalar joint arthritis.

Logistic regression showed that individuals with severe lumbar disc degeneration had significantly higher odds of developing severe ankle arthritis (OR: 1.93, P < .05). Similarly, individuals with severe tibiotalar joint arthritis were just as likely to develop severe lumbar DDD with an OR of 1.97 (P < .05).

Discussion

Multiple joint involvement in osteoarthritis is well established with a wide range of evidence linking lower extremity joint pathology and lumbar spinal disease. In 1983, Offierski and MacNab²⁰ were the first to describe hip-spine syndrome. In the next year, a study by Sponseller and colleagues²⁵ of pediatric patients after hip arthrodesis further substantiated the association between spine and extremity disease, and demonstrated a continued cause and effect relationship after surgery.

Lumbar spinal degeneration has also been correlated with knee osteoarthritis. Tsuji and colleagues²⁶ reported that degenerative changes in spinal alignment result in increased thigh muscle tension and knee flexion. Furthermore, in their radiographic analysis of 682 individuals, Horvath and colleagues²⁷ also showed that individuals with spinal degeneration had a higher prevalence of knee and hip osteoarthritis.

One might hypothesize from this evidence that lumbar spinal degeneration and ankle arthritis would also be interrelated, given their interconnected role in lower extremity force transmission. Surprisingly, the literature correlating lumbar degeneration and lower extremity osteoarthritis has overlooked this association and has focused solely on the hip and knee. To our knowledge, this study is the first to identify a statistically significant association between tibiotalar joint osteoarthritis and lumbar disc degeneration.

The literature supported analysis of our data. Miller and colleagues²⁸ evaluated disc degeneration in 600 autopsy specimens using the Nachemson²⁹ grading system. This system categorizes disc degeneration into 4 grades based on macroscopic appearance. Miller and colleagues²⁸ reported evidence of degenerative changes as early as the second decade of life, primarily involving the L3–L4 and L4–L5 levels. Of note, the Nachemson²⁹ classification system includes only evidence of marginal osteophytes in grade 4 disease, which was not identified by Miller and colleagues²⁸ until the fourth decade. These results were similar to those in our study, in which the L3-L4 and L4-L5 intervertebral levels were most commonly affected. However, in our study, significant degenerative changes were found in the third decade of life. 

In addition, the percentage of specimens with severe disc degeneration increased with each decade (Figure 8). A substantial amount of histologic evidence demonstrates the progression of disc degeneration with age. With increased age, there is a gradual decrease in the osmotic swelling of intervertebral discs³⁰ and a 2-fold decrease in disc hydration between adolescence and the eighth decade.³¹ Furthermore, the nucleus pulposus undergoes progressive fibrosis,^32,33 with a 5-fold decrease in the fixed-charge density of nucleus glycosaminoglycans,³⁴ and a 2-fold increase in intervertebral disc creep while under compression after age 30 years.³⁵

While analyzing our findings, we had difficulty in determining which pathologic condition debuts and, subsequently, affects the other. According to our results, the mean grade of tibiotalar joint arthritis was higher than that of DDD in specimens through the third and fourth decades of life (Figure 7). After the age of 50 years, the mean grade of DDD surpasses that of tibiotalar arthritis. This may be initially interpreted that development of tibiotalar joint arthritis precedes lumbar disc degeneration. Ankle osteoarthritis is relatively rare, and given that the vast majority of ankle osteoarthritis is secondary to trauma,²² we would expect to see a higher incidence of ankle osteoarthritis in a younger, more active cohort. In addition, given our finding that ankle arthritis is related to lumbar disc degeneration, one could speculate that tibiotalar arthritis at a young age predisposes an individual to developing lumbar degeneration later in life.

However, this conclusion is inherently flawed; closer examination of the data revealed that the mean grade of tibiotalar arthritis and DDD in the third and fourth decades is relatively low, between grade 0 and grade 1 (Figure 7). Therefore, it is difficult to arrive at a conclusion when comparing such small values. Second, we must remember that we are comparing an average value of disc degeneration across all lumbar levels. When a specimen has only 1 disc that is severely degenerated, this value is averaged across all 5 lumbar levels and, thus, the overall mean grade of arthrosis is significantly diminished.

In fact, data from previous studies concur with the second argument. Upper-level lumbar disc degeneration is relatively rare and the vast majority of patients with disc degeneration present with significant disease in only 1 or 2 discs.^36,37 Analysis of the specimens in this study revealed bony evidence of disc degeneration present at all 5 lumbar levels in over half of the specimens examined (57%). However, the majority of specimens in this cohort exhibit only low-grade degeneration. When specimens were analyzed for severe arthrosis (grade 3 and higher), nearly half of the specimens were found to have severe disease involving only 1 intervertebral disc (Figure 6). Data from Miller and colleagues²⁸ and the present study show that the upper lumbar levels were relatively spared; the L3-L4 and L4-L5 lumbar levels showed the highest prevalence and severity of degenerative change.

To address this issue, we evaluated the percentage of specimens per decade with severe arthrosis (grade 3 and higher) of at least 1 lumbar intervertebral disc and 1 tibiotalar joint. Severe lumbar disc degeneration was found to be more prevalent than severe ankle arthritis in individuals age 20 years or older (Figure 8). Therefore, we postulate that significant degenerative changes in the lumbar spine precede the development of severe ankle arthritis.

One can further speculate that sequelae from lumbar disc degeneration may lead to the development of tibiotalar arthritis, given our finding that severe lumbar degeneration predisposes an individual to the development of ankle arthritis. Because significant lumbar disc degeneration has long been known to result in both spinal nerve and cord compression, we hypothesize that this resultant neurocompression promotes altered gait and translation of atypical forces to the ankle and foot, thus predisposing to the onset and/or progression of osteoarthritis. In support of this hypothesis, Morag and colleagues¹⁵ demonstrated that neurologic compression produced an altered posture and gait because of lost motor function and afferent proprioceptive sensation. This form of neurologic compromise may exert atypical forces upon the foot and ankle, predisposing the joint to accelerated wear and primary arthrosis.

In addition, DDD involving 3 or more lumbar intervertebral levels was found to significantly increase the likelihood of the subject having severe tibiotalar joint arthritis. Provided that lumbar disc degeneration typically involves significant degeneration at 1 level, we assume that significant arthrosis at 3 or more levels correlates to an overall more severe DDD with a higher corresponding likelihood of neural compression. However, compression of peripheral lower extremity nerves has been shown to result in neuropathic arthropathy akin to the diabetic Charcot foot.³⁸ This could be a possible mechanism of accelerated ankle arthritis, but this study did not examine soft-tissue disease nor take into account other medical comorbidities of each specimen, including genetic predispositions towards osteoarthritis.

It should be noted that the aforementioned causative relationship between lumbar disc degeneration and tibiotalar arthritis is speculative and cannot be demonstrated definitively by this investigation. We acknowledge limitations of this study and the need for further research of the possible causative mechanism(s) of accelerated ankle arthrosis secondary to lumbar spinal disease. Ideally, the questions posed by our report would be answered via a large prospective cohort study that utilized both serial imaging and autopsy analysis. Unfortunately, this form of study is logistically and financially difficult to perform.

This was a retrospective cadaveric study in which determination of arthrosis severity was based solely on bony evidence. Therefore, the role of soft-tissue disease in the pathogenesis of arthrosis of the lumbar spine and tibiotalar joint could not be assessed, nor could definitive associations to clinically symptomatic disease. We made the assumption that progression of bone degeneration in both the lumbar spine and tibiotalar joint corresponded equally to the associated soft-tissue changes. Given this assumption, we cannot definitively conclude that degeneration of the lumbar spine precedes that of the ankle, because the absence of magnetic resonance imaging or fresh autopsy specimens in our study misses the early degenerative changes in the discs that precede the bony alteration measured in our study. Furthermore, readers should note that since this study compared only bone morphology, no emphasis was placed on clinical manifestation of lumbar disc degeneration or tibiotalar joint arthritis. As mentioned earlier, radiologic evidence of disc degeneration was found in 90% of adults age 50 to 59 years, according to a study by Hult⁵; however, it is important to note that not all individuals studied were symptomatic clinically. Unfortunately, medical records were not available for the bony specimens, and clinical correlations could not be assessed during this investigation.

Furthermore, no special attention was given to other pathologic conditions observed during specimen measurement. The presence of diseases, such as osteoporosis, spondylolysis, or previous traumatic injury, may have had implications in the resultant joint degeneration. Finally, the evaluation of arthrosis was performed subjectively without measuring reliability. However, the present analysis includes a large sample, each joint type was reviewed by a single examiner, and used a classification system that was modeled on a validated grading system. Ideally, multiple individuals should have been used for each type of measurement, with subsequent analysis of intraobserver and interobserver reliability.

Conclusion

Based on our study of a large population of adult skeletal specimens, we ascertained that lumbar intervertebral disc degeneration and tibiotalar osteoarthritis are associated. The prevalence of severe lumbar disc degeneration was higher than that of tibiotalar joint arthritis in individuals age 20 years or older. This may suggest that gait changes from disc degeneration or neural compression in the lumbar spine may play a role in the development of ankle osteoarthritis. Additionally, subjects with severe disc degeneration were twice as likely to develop significant tibiotalar osteoarthritis. This must be considered in the differential when treating patients with degenerative changes of the lumbar spine and leg pain.

Osteoarthritis is the most common joint disorder, resulting in significant morbidity and disability. The worldwide prevalence of osteoarthritis was estimated at more than 151 million people, according to data published in 2004.¹ In the United States, almost 27 million adults age 25 years and older suffer from clinically apparent disease.² The spine is one of the most commonly affected joints of arthritis, and idiopathic low back pain is the most frequent complaint in the adult population.³ In adults with low back pain, evidence of lumbar intervertebral disc degeneration is often found on radiography.⁴ In 1 study, evidence of disc degeneration was found in 90% of adults age 50 to 59 years.⁵

Degenerative spinal disease most commonly affects the lumbar spine due to its high degree of mobility and weight-loading.^6,7 Clinical^8,9 and experimental studies¹⁰ have suggested that the degenerative changes in the lumbar spine begin in the intervertebral discs. Degenerative disc disease (DDD) results from a continuum of dehydration, degradation, and remodeling of the intervertebral discs and neighboring vertebrae to accommodate the changes in physical loading.^11-13 This results in disc-space narrowing, disc bulging and herniation, vertebral rim osteophyte formation, and endplate sclerosis.^7,14 Symptomatic neural compression may occur, often manifested by localized lower back and extremity pain, as well as sensory loss and weakness of the lower extremities.^15-17 Changes in posture and gait may result because of altered sensation, and the consequent abnormal force transmission may predispose joints to accelerated wear and arthrosis.^15,18

Numerous studies have delineated the association between lumbar spinal disorders and lower extremity arthrosis. Of note, research has demonstrated that hip and/or knee pathology and gait alteration may promote low back pain and lumbar disc degeneration.^19-21 Although spinal abnormalities, such as scoliosis, may predispose an individual to accelerated hip degeneration,²⁰ no studies have investigated the relationship between lumbar DDD and ankle osteoarthritis.

Ankle arthritis differs from hip and knee arthritis demographically, occurring approximately 9 times less frequently.²¹ The ankle joint is subjected to more weight-bearing force per square centimeter and is more commonly injured than any other joint in the body.²¹ Trauma and/or abnormal ankle mechanics are the most common causes of degenerative ankle arthritis.²² Other potential causes include inflammatory arthropathies, neuropathic arthropathy, infection, and tumor. The purpose of this study was to determine if a relationship exists between ankle arthrosis and lumbar disc degeneration, and to delineate if one may promote the onset or progression of the other.

Materials and Methods

We randomly chose 710 cadaveric specimens from the Hamann-Todd Osteological Collection in Cleveland, Ohio. The Hamann-Todd Collection contains skeletal remains from more than 3000 individuals who died in Cleveland, Ohio between 1893 and 1938. The cohort for this study included 583 male and 127 female cadavers, ranging in age from 17 to 105 years at the time of death. Table 1 shows the breakdown of these specimens according to age group; of the 710 specimens, 306 were of African American ancestry, and 404 were Caucasian.

Lumbar DDD was graded at each lumbar spinal level by a single examiner using the Eubanks modification²³ of the Kettler and Wilke classification of vertebral endplate osteophytosis²⁴:

Grade 0: normal vertebral endplates;

Grade 1: mild arthrosis, with evidence of osteophytic reaction involving up to 50% of the vertebral endplates;

Grade 2: moderate arthrosis, with evidence of osteophytic reaction involving 50% to 100% of the vertebral endplates;

Grade 3: severe arthrosis, with evidence of osteophytic reaction involving 100% of the vertebral endplates. Osteophytes are hypertrophic and bridging the joint space (Figure 1);

Grade 4: complete ankylosis. 

Tibiotalar joint osteoarthritis was evaluated by a single examiner using a modification of the Kellgren-Lawrence classification⁴ for knee osteoarthritis:

Grade 0: no discernable wear/osteophytes;

Grade 1: 1-mm osteophyte(s) and/or <25% surface wear;

Grade 2: 1- to 2-mm osteophyte(s) and/or 25% to 50% joint surface;

Grade 3: 2- to 3-mm osteophyte(s) and/or >50% joint surface (Figure 2);

Grade 4: multiple large osteophytes and/or definite bony end deformity.

Statistical analysis was performed on the compiled data using Stata software (StataCorp, College Station, Texas). Linear and logistic regression analyses correcting for confounding factors of age, sex, race, and height were performed using a standard P-value cutoff (P < .05) and 95% confidence interval to determine statistical significance.

Results         

Patients were considered to have osteoarthritis of the tibiotalar joint if either of the extremities measured grade 1 or higher. Of the 710 specimens selected, 14 specimens did not have adequate bone available for bilateral tibiotalar joint measurement, either from extensive bone degradation or amputation. Of the remaining 696 specimens, 586 had some degree of tibiotalar osteoarthritis present (Table 2). Regression analysis showed a significant positive association between right- and left-ankle osteoarthritis (coefficient: 0.491, P < .01). Tibiotalar joint arthritis was classified as severe if either extremity had arthrosis of grade 3 or higher. Of the 586 specimens that had tibiotalar joint arthritis, only 16% (97 specimens) had severe tibiotalar joint arthritis.

Data regarding lumbar disc degeneration were available for 516 of the 710 specimens selected, 443 of which showed some disc degeneration. Disc degeneration was most prevalent and significant at the L4-L5 and L3-L4 intervertebral levels (Figures 3, 4). Of these 516 specimens, 30 had degeneration at 1 level, 47 specimens had degeneration at 2 levels, 29 specimens had degeneration at 3 levels, 52 had degeneration at 4 levels, and 285 specimens had degeneration at all 5 lumbar levels. The majority of specimens were found to have some degree of degeneration at all 5 lumbar spinal levels (Figure 5). Severe lumbar DDD was defined as grade 3 or higher osteoarthritis present in at least 1 of the 5 lumbar levels. Of the 516 specimens that showed some degree of disc degeneration, 152 were classified as severe. When stratified by number of spinal levels, only 30% of specimens were found to have evidence of severe arthrosis, the majority of which was located at only 1 lumbar segment (Figure 6).

Linear regression analysis of the data showed a statistically significant positive association between lumbar disc degeneration and tibiotalar osteoarthritis (coefficient: 0.844, P < .01), even when correcting for confounding factors, such as age, sex, and race (coefficient: 0.331, P < .01).

Additional analysis of the data demonstrated that tibiotalar joint arthritis remained significantly associated with lumbar DDD across each lumbar level: L1-L2 (coefficient: 0.269, P < .01), L2-L3 (coefficient: 0.283, P < .01), L3-L4 (coefficient: 0.299, P < .01), L4-L5 (coefficient: 0.240, P < .02), L5-S1 (coefficient: 0.167, P < .05).

The presence of 3 or more levels of lumbar DDD significantly increased the possibility of developing severe tibiotalar joint arthritis. Lumbar DDD that encompassed 3 levels showed the highest odds for development of severe tibiotalar joint arthritis with an odds ratio (OR) of 20.542 (Table 3).

When subjects were compared by decade, the mean grade of tibiotalar joint arthritis was significantly higher than lumbar DDD in specimens who died in their 20s and 30s. This difference was insignificant in the fourth decade, and thereafter the mean value of lumbar DDD surpassed that of tibiotalar joint arthritis (Figure 7).

In contrast, severe lumbar DDD was more prevalent than severe tibiotalar joint arthritis in individuals age 20 years or older (Figure 8). There were no specimens under age 20 years with severe lumbar DDD or severe tibiotalar joint arthritis.

Logistic regression showed that individuals with severe lumbar disc degeneration had significantly higher odds of developing severe ankle arthritis (OR: 1.93, P < .05). Similarly, individuals with severe tibiotalar joint arthritis were just as likely to develop severe lumbar DDD with an OR of 1.97 (P < .05).

Discussion

Multiple joint involvement in osteoarthritis is well established with a wide range of evidence linking lower extremity joint pathology and lumbar spinal disease. In 1983, Offierski and MacNab²⁰ were the first to describe hip-spine syndrome. In the next year, a study by Sponseller and colleagues²⁵ of pediatric patients after hip arthrodesis further substantiated the association between spine and extremity disease, and demonstrated a continued cause and effect relationship after surgery.

Lumbar spinal degeneration has also been correlated with knee osteoarthritis. Tsuji and colleagues²⁶ reported that degenerative changes in spinal alignment result in increased thigh muscle tension and knee flexion. Furthermore, in their radiographic analysis of 682 individuals, Horvath and colleagues²⁷ also showed that individuals with spinal degeneration had a higher prevalence of knee and hip osteoarthritis.

One might hypothesize from this evidence that lumbar spinal degeneration and ankle arthritis would also be interrelated, given their interconnected role in lower extremity force transmission. Surprisingly, the literature correlating lumbar degeneration and lower extremity osteoarthritis has overlooked this association and has focused solely on the hip and knee. To our knowledge, this study is the first to identify a statistically significant association between tibiotalar joint osteoarthritis and lumbar disc degeneration.

The literature supported analysis of our data. Miller and colleagues²⁸ evaluated disc degeneration in 600 autopsy specimens using the Nachemson²⁹ grading system. This system categorizes disc degeneration into 4 grades based on macroscopic appearance. Miller and colleagues²⁸ reported evidence of degenerative changes as early as the second decade of life, primarily involving the L3–L4 and L4–L5 levels. Of note, the Nachemson²⁹ classification system includes only evidence of marginal osteophytes in grade 4 disease, which was not identified by Miller and colleagues²⁸ until the fourth decade. These results were similar to those in our study, in which the L3-L4 and L4-L5 intervertebral levels were most commonly affected. However, in our study, significant degenerative changes were found in the third decade of life. 

In addition, the percentage of specimens with severe disc degeneration increased with each decade (Figure 8). A substantial amount of histologic evidence demonstrates the progression of disc degeneration with age. With increased age, there is a gradual decrease in the osmotic swelling of intervertebral discs³⁰ and a 2-fold decrease in disc hydration between adolescence and the eighth decade.³¹ Furthermore, the nucleus pulposus undergoes progressive fibrosis,^32,33 with a 5-fold decrease in the fixed-charge density of nucleus glycosaminoglycans,³⁴ and a 2-fold increase in intervertebral disc creep while under compression after age 30 years.³⁵

While analyzing our findings, we had difficulty in determining which pathologic condition debuts and, subsequently, affects the other. According to our results, the mean grade of tibiotalar joint arthritis was higher than that of DDD in specimens through the third and fourth decades of life (Figure 7). After the age of 50 years, the mean grade of DDD surpasses that of tibiotalar arthritis. This may be initially interpreted that development of tibiotalar joint arthritis precedes lumbar disc degeneration. Ankle osteoarthritis is relatively rare, and given that the vast majority of ankle osteoarthritis is secondary to trauma,²² we would expect to see a higher incidence of ankle osteoarthritis in a younger, more active cohort. In addition, given our finding that ankle arthritis is related to lumbar disc degeneration, one could speculate that tibiotalar arthritis at a young age predisposes an individual to developing lumbar degeneration later in life.

However, this conclusion is inherently flawed; closer examination of the data revealed that the mean grade of tibiotalar arthritis and DDD in the third and fourth decades is relatively low, between grade 0 and grade 1 (Figure 7). Therefore, it is difficult to arrive at a conclusion when comparing such small values. Second, we must remember that we are comparing an average value of disc degeneration across all lumbar levels. When a specimen has only 1 disc that is severely degenerated, this value is averaged across all 5 lumbar levels and, thus, the overall mean grade of arthrosis is significantly diminished.

In fact, data from previous studies concur with the second argument. Upper-level lumbar disc degeneration is relatively rare and the vast majority of patients with disc degeneration present with significant disease in only 1 or 2 discs.^36,37 Analysis of the specimens in this study revealed bony evidence of disc degeneration present at all 5 lumbar levels in over half of the specimens examined (57%). However, the majority of specimens in this cohort exhibit only low-grade degeneration. When specimens were analyzed for severe arthrosis (grade 3 and higher), nearly half of the specimens were found to have severe disease involving only 1 intervertebral disc (Figure 6). Data from Miller and colleagues²⁸ and the present study show that the upper lumbar levels were relatively spared; the L3-L4 and L4-L5 lumbar levels showed the highest prevalence and severity of degenerative change.

To address this issue, we evaluated the percentage of specimens per decade with severe arthrosis (grade 3 and higher) of at least 1 lumbar intervertebral disc and 1 tibiotalar joint. Severe lumbar disc degeneration was found to be more prevalent than severe ankle arthritis in individuals age 20 years or older (Figure 8). Therefore, we postulate that significant degenerative changes in the lumbar spine precede the development of severe ankle arthritis.

One can further speculate that sequelae from lumbar disc degeneration may lead to the development of tibiotalar arthritis, given our finding that severe lumbar degeneration predisposes an individual to the development of ankle arthritis. Because significant lumbar disc degeneration has long been known to result in both spinal nerve and cord compression, we hypothesize that this resultant neurocompression promotes altered gait and translation of atypical forces to the ankle and foot, thus predisposing to the onset and/or progression of osteoarthritis. In support of this hypothesis, Morag and colleagues¹⁵ demonstrated that neurologic compression produced an altered posture and gait because of lost motor function and afferent proprioceptive sensation. This form of neurologic compromise may exert atypical forces upon the foot and ankle, predisposing the joint to accelerated wear and primary arthrosis.

In addition, DDD involving 3 or more lumbar intervertebral levels was found to significantly increase the likelihood of the subject having severe tibiotalar joint arthritis. Provided that lumbar disc degeneration typically involves significant degeneration at 1 level, we assume that significant arthrosis at 3 or more levels correlates to an overall more severe DDD with a higher corresponding likelihood of neural compression. However, compression of peripheral lower extremity nerves has been shown to result in neuropathic arthropathy akin to the diabetic Charcot foot.³⁸ This could be a possible mechanism of accelerated ankle arthritis, but this study did not examine soft-tissue disease nor take into account other medical comorbidities of each specimen, including genetic predispositions towards osteoarthritis.

It should be noted that the aforementioned causative relationship between lumbar disc degeneration and tibiotalar arthritis is speculative and cannot be demonstrated definitively by this investigation. We acknowledge limitations of this study and the need for further research of the possible causative mechanism(s) of accelerated ankle arthrosis secondary to lumbar spinal disease. Ideally, the questions posed by our report would be answered via a large prospective cohort study that utilized both serial imaging and autopsy analysis. Unfortunately, this form of study is logistically and financially difficult to perform.

This was a retrospective cadaveric study in which determination of arthrosis severity was based solely on bony evidence. Therefore, the role of soft-tissue disease in the pathogenesis of arthrosis of the lumbar spine and tibiotalar joint could not be assessed, nor could definitive associations to clinically symptomatic disease. We made the assumption that progression of bone degeneration in both the lumbar spine and tibiotalar joint corresponded equally to the associated soft-tissue changes. Given this assumption, we cannot definitively conclude that degeneration of the lumbar spine precedes that of the ankle, because the absence of magnetic resonance imaging or fresh autopsy specimens in our study misses the early degenerative changes in the discs that precede the bony alteration measured in our study. Furthermore, readers should note that since this study compared only bone morphology, no emphasis was placed on clinical manifestation of lumbar disc degeneration or tibiotalar joint arthritis. As mentioned earlier, radiologic evidence of disc degeneration was found in 90% of adults age 50 to 59 years, according to a study by Hult⁵; however, it is important to note that not all individuals studied were symptomatic clinically. Unfortunately, medical records were not available for the bony specimens, and clinical correlations could not be assessed during this investigation.

Furthermore, no special attention was given to other pathologic conditions observed during specimen measurement. The presence of diseases, such as osteoporosis, spondylolysis, or previous traumatic injury, may have had implications in the resultant joint degeneration. Finally, the evaluation of arthrosis was performed subjectively without measuring reliability. However, the present analysis includes a large sample, each joint type was reviewed by a single examiner, and used a classification system that was modeled on a validated grading system. Ideally, multiple individuals should have been used for each type of measurement, with subsequent analysis of intraobserver and interobserver reliability.

Conclusion

Based on our study of a large population of adult skeletal specimens, we ascertained that lumbar intervertebral disc degeneration and tibiotalar osteoarthritis are associated. The prevalence of severe lumbar disc degeneration was higher than that of tibiotalar joint arthritis in individuals age 20 years or older. This may suggest that gait changes from disc degeneration or neural compression in the lumbar spine may play a role in the development of ankle osteoarthritis. Additionally, subjects with severe disc degeneration were twice as likely to develop significant tibiotalar osteoarthritis. This must be considered in the differential when treating patients with degenerative changes of the lumbar spine and leg pain.

Osteoarthritis is the most common joint disorder, resulting in significant morbidity and disability. The worldwide prevalence of osteoarthritis was estimated at more than 151 million people, according to data published in 2004.¹ In the United States, almost 27 million adults age 25 years and older suffer from clinically apparent disease.² The spine is one of the most commonly affected joints of arthritis, and idiopathic low back pain is the most frequent complaint in the adult population.³ In adults with low back pain, evidence of lumbar intervertebral disc degeneration is often found on radiography.⁴ In 1 study, evidence of disc degeneration was found in 90% of adults age 50 to 59 years.⁵

Degenerative spinal disease most commonly affects the lumbar spine due to its high degree of mobility and weight-loading.^6,7 Clinical^8,9 and experimental studies¹⁰ have suggested that the degenerative changes in the lumbar spine begin in the intervertebral discs. Degenerative disc disease (DDD) results from a continuum of dehydration, degradation, and remodeling of the intervertebral discs and neighboring vertebrae to accommodate the changes in physical loading.^11-13 This results in disc-space narrowing, disc bulging and herniation, vertebral rim osteophyte formation, and endplate sclerosis.^7,14 Symptomatic neural compression may occur, often manifested by localized lower back and extremity pain, as well as sensory loss and weakness of the lower extremities.^15-17 Changes in posture and gait may result because of altered sensation, and the consequent abnormal force transmission may predispose joints to accelerated wear and arthrosis.^15,18

Numerous studies have delineated the association between lumbar spinal disorders and lower extremity arthrosis. Of note, research has demonstrated that hip and/or knee pathology and gait alteration may promote low back pain and lumbar disc degeneration.^19-21 Although spinal abnormalities, such as scoliosis, may predispose an individual to accelerated hip degeneration,²⁰ no studies have investigated the relationship between lumbar DDD and ankle osteoarthritis.

Ankle arthritis differs from hip and knee arthritis demographically, occurring approximately 9 times less frequently.²¹ The ankle joint is subjected to more weight-bearing force per square centimeter and is more commonly injured than any other joint in the body.²¹ Trauma and/or abnormal ankle mechanics are the most common causes of degenerative ankle arthritis.²² Other potential causes include inflammatory arthropathies, neuropathic arthropathy, infection, and tumor. The purpose of this study was to determine if a relationship exists between ankle arthrosis and lumbar disc degeneration, and to delineate if one may promote the onset or progression of the other.

Materials and Methods

We randomly chose 710 cadaveric specimens from the Hamann-Todd Osteological Collection in Cleveland, Ohio. The Hamann-Todd Collection contains skeletal remains from more than 3000 individuals who died in Cleveland, Ohio between 1893 and 1938. The cohort for this study included 583 male and 127 female cadavers, ranging in age from 17 to 105 years at the time of death. Table 1 shows the breakdown of these specimens according to age group; of the 710 specimens, 306 were of African American ancestry, and 404 were Caucasian.

Lumbar DDD was graded at each lumbar spinal level by a single examiner using the Eubanks modification²³ of the Kettler and Wilke classification of vertebral endplate osteophytosis²⁴:

Grade 0: normal vertebral endplates;

Grade 1: mild arthrosis, with evidence of osteophytic reaction involving up to 50% of the vertebral endplates;

Grade 2: moderate arthrosis, with evidence of osteophytic reaction involving 50% to 100% of the vertebral endplates;

Grade 3: severe arthrosis, with evidence of osteophytic reaction involving 100% of the vertebral endplates. Osteophytes are hypertrophic and bridging the joint space (Figure 1);

Grade 4: complete ankylosis. 

Tibiotalar joint osteoarthritis was evaluated by a single examiner using a modification of the Kellgren-Lawrence classification⁴ for knee osteoarthritis:

Grade 0: no discernable wear/osteophytes;

Grade 1: 1-mm osteophyte(s) and/or <25% surface wear;

Grade 2: 1- to 2-mm osteophyte(s) and/or 25% to 50% joint surface;

Grade 3: 2- to 3-mm osteophyte(s) and/or >50% joint surface (Figure 2);

Grade 4: multiple large osteophytes and/or definite bony end deformity.

Statistical analysis was performed on the compiled data using Stata software (StataCorp, College Station, Texas). Linear and logistic regression analyses correcting for confounding factors of age, sex, race, and height were performed using a standard P-value cutoff (P < .05) and 95% confidence interval to determine statistical significance.

Results         

Patients were considered to have osteoarthritis of the tibiotalar joint if either of the extremities measured grade 1 or higher. Of the 710 specimens selected, 14 specimens did not have adequate bone available for bilateral tibiotalar joint measurement, either from extensive bone degradation or amputation. Of the remaining 696 specimens, 586 had some degree of tibiotalar osteoarthritis present (Table 2). Regression analysis showed a significant positive association between right- and left-ankle osteoarthritis (coefficient: 0.491, P < .01). Tibiotalar joint arthritis was classified as severe if either extremity had arthrosis of grade 3 or higher. Of the 586 specimens that had tibiotalar joint arthritis, only 16% (97 specimens) had severe tibiotalar joint arthritis.

Data regarding lumbar disc degeneration were available for 516 of the 710 specimens selected, 443 of which showed some disc degeneration. Disc degeneration was most prevalent and significant at the L4-L5 and L3-L4 intervertebral levels (Figures 3, 4). Of these 516 specimens, 30 had degeneration at 1 level, 47 specimens had degeneration at 2 levels, 29 specimens had degeneration at 3 levels, 52 had degeneration at 4 levels, and 285 specimens had degeneration at all 5 lumbar levels. The majority of specimens were found to have some degree of degeneration at all 5 lumbar spinal levels (Figure 5). Severe lumbar DDD was defined as grade 3 or higher osteoarthritis present in at least 1 of the 5 lumbar levels. Of the 516 specimens that showed some degree of disc degeneration, 152 were classified as severe. When stratified by number of spinal levels, only 30% of specimens were found to have evidence of severe arthrosis, the majority of which was located at only 1 lumbar segment (Figure 6).

Linear regression analysis of the data showed a statistically significant positive association between lumbar disc degeneration and tibiotalar osteoarthritis (coefficient: 0.844, P < .01), even when correcting for confounding factors, such as age, sex, and race (coefficient: 0.331, P < .01).

Additional analysis of the data demonstrated that tibiotalar joint arthritis remained significantly associated with lumbar DDD across each lumbar level: L1-L2 (coefficient: 0.269, P < .01), L2-L3 (coefficient: 0.283, P < .01), L3-L4 (coefficient: 0.299, P < .01), L4-L5 (coefficient: 0.240, P < .02), L5-S1 (coefficient: 0.167, P < .05).

The presence of 3 or more levels of lumbar DDD significantly increased the possibility of developing severe tibiotalar joint arthritis. Lumbar DDD that encompassed 3 levels showed the highest odds for development of severe tibiotalar joint arthritis with an odds ratio (OR) of 20.542 (Table 3).

When subjects were compared by decade, the mean grade of tibiotalar joint arthritis was significantly higher than lumbar DDD in specimens who died in their 20s and 30s. This difference was insignificant in the fourth decade, and thereafter the mean value of lumbar DDD surpassed that of tibiotalar joint arthritis (Figure 7).

In contrast, severe lumbar DDD was more prevalent than severe tibiotalar joint arthritis in individuals age 20 years or older (Figure 8). There were no specimens under age 20 years with severe lumbar DDD or severe tibiotalar joint arthritis.

Logistic regression showed that individuals with severe lumbar disc degeneration had significantly higher odds of developing severe ankle arthritis (OR: 1.93, P < .05). Similarly, individuals with severe tibiotalar joint arthritis were just as likely to develop severe lumbar DDD with an OR of 1.97 (P < .05).

Discussion

Multiple joint involvement in osteoarthritis is well established with a wide range of evidence linking lower extremity joint pathology and lumbar spinal disease. In 1983, Offierski and MacNab²⁰ were the first to describe hip-spine syndrome. In the next year, a study by Sponseller and colleagues²⁵ of pediatric patients after hip arthrodesis further substantiated the association between spine and extremity disease, and demonstrated a continued cause and effect relationship after surgery.

Lumbar spinal degeneration has also been correlated with knee osteoarthritis. Tsuji and colleagues²⁶ reported that degenerative changes in spinal alignment result in increased thigh muscle tension and knee flexion. Furthermore, in their radiographic analysis of 682 individuals, Horvath and colleagues²⁷ also showed that individuals with spinal degeneration had a higher prevalence of knee and hip osteoarthritis.

One might hypothesize from this evidence that lumbar spinal degeneration and ankle arthritis would also be interrelated, given their interconnected role in lower extremity force transmission. Surprisingly, the literature correlating lumbar degeneration and lower extremity osteoarthritis has overlooked this association and has focused solely on the hip and knee. To our knowledge, this study is the first to identify a statistically significant association between tibiotalar joint osteoarthritis and lumbar disc degeneration.

The literature supported analysis of our data. Miller and colleagues²⁸ evaluated disc degeneration in 600 autopsy specimens using the Nachemson²⁹ grading system. This system categorizes disc degeneration into 4 grades based on macroscopic appearance. Miller and colleagues²⁸ reported evidence of degenerative changes as early as the second decade of life, primarily involving the L3–L4 and L4–L5 levels. Of note, the Nachemson²⁹ classification system includes only evidence of marginal osteophytes in grade 4 disease, which was not identified by Miller and colleagues²⁸ until the fourth decade. These results were similar to those in our study, in which the L3-L4 and L4-L5 intervertebral levels were most commonly affected. However, in our study, significant degenerative changes were found in the third decade of life. 

In addition, the percentage of specimens with severe disc degeneration increased with each decade (Figure 8). A substantial amount of histologic evidence demonstrates the progression of disc degeneration with age. With increased age, there is a gradual decrease in the osmotic swelling of intervertebral discs³⁰ and a 2-fold decrease in disc hydration between adolescence and the eighth decade.³¹ Furthermore, the nucleus pulposus undergoes progressive fibrosis,^32,33 with a 5-fold decrease in the fixed-charge density of nucleus glycosaminoglycans,³⁴ and a 2-fold increase in intervertebral disc creep while under compression after age 30 years.³⁵

While analyzing our findings, we had difficulty in determining which pathologic condition debuts and, subsequently, affects the other. According to our results, the mean grade of tibiotalar joint arthritis was higher than that of DDD in specimens through the third and fourth decades of life (Figure 7). After the age of 50 years, the mean grade of DDD surpasses that of tibiotalar arthritis. This may be initially interpreted that development of tibiotalar joint arthritis precedes lumbar disc degeneration. Ankle osteoarthritis is relatively rare, and given that the vast majority of ankle osteoarthritis is secondary to trauma,²² we would expect to see a higher incidence of ankle osteoarthritis in a younger, more active cohort. In addition, given our finding that ankle arthritis is related to lumbar disc degeneration, one could speculate that tibiotalar arthritis at a young age predisposes an individual to developing lumbar degeneration later in life.

However, this conclusion is inherently flawed; closer examination of the data revealed that the mean grade of tibiotalar arthritis and DDD in the third and fourth decades is relatively low, between grade 0 and grade 1 (Figure 7). Therefore, it is difficult to arrive at a conclusion when comparing such small values. Second, we must remember that we are comparing an average value of disc degeneration across all lumbar levels. When a specimen has only 1 disc that is severely degenerated, this value is averaged across all 5 lumbar levels and, thus, the overall mean grade of arthrosis is significantly diminished.

In fact, data from previous studies concur with the second argument. Upper-level lumbar disc degeneration is relatively rare and the vast majority of patients with disc degeneration present with significant disease in only 1 or 2 discs.^36,37 Analysis of the specimens in this study revealed bony evidence of disc degeneration present at all 5 lumbar levels in over half of the specimens examined (57%). However, the majority of specimens in this cohort exhibit only low-grade degeneration. When specimens were analyzed for severe arthrosis (grade 3 and higher), nearly half of the specimens were found to have severe disease involving only 1 intervertebral disc (Figure 6). Data from Miller and colleagues²⁸ and the present study show that the upper lumbar levels were relatively spared; the L3-L4 and L4-L5 lumbar levels showed the highest prevalence and severity of degenerative change.

To address this issue, we evaluated the percentage of specimens per decade with severe arthrosis (grade 3 and higher) of at least 1 lumbar intervertebral disc and 1 tibiotalar joint. Severe lumbar disc degeneration was found to be more prevalent than severe ankle arthritis in individuals age 20 years or older (Figure 8). Therefore, we postulate that significant degenerative changes in the lumbar spine precede the development of severe ankle arthritis.

One can further speculate that sequelae from lumbar disc degeneration may lead to the development of tibiotalar arthritis, given our finding that severe lumbar degeneration predisposes an individual to the development of ankle arthritis. Because significant lumbar disc degeneration has long been known to result in both spinal nerve and cord compression, we hypothesize that this resultant neurocompression promotes altered gait and translation of atypical forces to the ankle and foot, thus predisposing to the onset and/or progression of osteoarthritis. In support of this hypothesis, Morag and colleagues¹⁵ demonstrated that neurologic compression produced an altered posture and gait because of lost motor function and afferent proprioceptive sensation. This form of neurologic compromise may exert atypical forces upon the foot and ankle, predisposing the joint to accelerated wear and primary arthrosis.

In addition, DDD involving 3 or more lumbar intervertebral levels was found to significantly increase the likelihood of the subject having severe tibiotalar joint arthritis. Provided that lumbar disc degeneration typically involves significant degeneration at 1 level, we assume that significant arthrosis at 3 or more levels correlates to an overall more severe DDD with a higher corresponding likelihood of neural compression. However, compression of peripheral lower extremity nerves has been shown to result in neuropathic arthropathy akin to the diabetic Charcot foot.³⁸ This could be a possible mechanism of accelerated ankle arthritis, but this study did not examine soft-tissue disease nor take into account other medical comorbidities of each specimen, including genetic predispositions towards osteoarthritis.

It should be noted that the aforementioned causative relationship between lumbar disc degeneration and tibiotalar arthritis is speculative and cannot be demonstrated definitively by this investigation. We acknowledge limitations of this study and the need for further research of the possible causative mechanism(s) of accelerated ankle arthrosis secondary to lumbar spinal disease. Ideally, the questions posed by our report would be answered via a large prospective cohort study that utilized both serial imaging and autopsy analysis. Unfortunately, this form of study is logistically and financially difficult to perform.

This was a retrospective cadaveric study in which determination of arthrosis severity was based solely on bony evidence. Therefore, the role of soft-tissue disease in the pathogenesis of arthrosis of the lumbar spine and tibiotalar joint could not be assessed, nor could definitive associations to clinically symptomatic disease. We made the assumption that progression of bone degeneration in both the lumbar spine and tibiotalar joint corresponded equally to the associated soft-tissue changes. Given this assumption, we cannot definitively conclude that degeneration of the lumbar spine precedes that of the ankle, because the absence of magnetic resonance imaging or fresh autopsy specimens in our study misses the early degenerative changes in the discs that precede the bony alteration measured in our study. Furthermore, readers should note that since this study compared only bone morphology, no emphasis was placed on clinical manifestation of lumbar disc degeneration or tibiotalar joint arthritis. As mentioned earlier, radiologic evidence of disc degeneration was found in 90% of adults age 50 to 59 years, according to a study by Hult⁵; however, it is important to note that not all individuals studied were symptomatic clinically. Unfortunately, medical records were not available for the bony specimens, and clinical correlations could not be assessed during this investigation.

Furthermore, no special attention was given to other pathologic conditions observed during specimen measurement. The presence of diseases, such as osteoporosis, spondylolysis, or previous traumatic injury, may have had implications in the resultant joint degeneration. Finally, the evaluation of arthrosis was performed subjectively without measuring reliability. However, the present analysis includes a large sample, each joint type was reviewed by a single examiner, and used a classification system that was modeled on a validated grading system. Ideally, multiple individuals should have been used for each type of measurement, with subsequent analysis of intraobserver and interobserver reliability.

Conclusion

Based on our study of a large population of adult skeletal specimens, we ascertained that lumbar intervertebral disc degeneration and tibiotalar osteoarthritis are associated. The prevalence of severe lumbar disc degeneration was higher than that of tibiotalar joint arthritis in individuals age 20 years or older. This may suggest that gait changes from disc degeneration or neural compression in the lumbar spine may play a role in the development of ankle osteoarthritis. Additionally, subjects with severe disc degeneration were twice as likely to develop significant tibiotalar osteoarthritis. This must be considered in the differential when treating patients with degenerative changes of the lumbar spine and leg pain.

LAS VEGAS—Chronic low back pain can limit everyday activities, including sex. New research presented at the 2015 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) found that 70% of patients consider sexual activity “relevant” to their quality of life, and patients who receive surgical treatment for spinal degenerative spondylolisthesis (DS) and spinal stenosis (SS) were twice as likely to report no pain during sex.

“Our current research sheds light on the effect that spinal surgery has on a patient’s sex life and begins to describe the impact spinal disease has on this very important aspect of life,” said senior study author Shane Burch, MD, an orthopedic surgeon at the University of California, San Francisco.

Researchers reviewed data from the Spine Patients Outcomes Research Trial (SPORT) of 1,235 patients diagnosed with DS or SS. Patient responses to the question, “In the past week, how has pain affected your sex life?” were used to determine sex-life relevance. Patients selecting the options, “unable to answer” or “does not apply to me,” were placed in the sex-life non-relevant (NR) group. Patients selecting other options were placed into the sex-life relevant (SLR) group. The mean age of patients in the NR and SLR groups were 68 years and 63 years, respectively. Seventy percent of patients were in the SLR group.

There was a higher association of being in the NR group for patients who were female or unmarried, or had a coexisting joint problem or hypertension. At baseline, 40% of SLR patients reported having some level of pain related to sex.

The study included 825 patients, 449 with SS and 376 with DS. A total of 294 patients received nonoperative treatment, and 531 received surgical treatment. The nonoperative patients were more likely to report pain related to sex at all follow-up time frames (from 41% compared to 20%). The percentages remained constant during annual visits at 1 year, 2 years, 3 years, and 4 years after surgery. Prior studies found that 41% of physicians routinely question patients with lumbar disc herniation about sexual problems.

“Our current research has two important findings,” said Dr. Horst. “The first is that sexual activity and sexual function is an important consideration for patients with degenerative spine conditions. The study also shows that sexual function is a more relevant consideration for patients who are married, younger, and male. The second important finding of our study is that patients with degenerative conditions of the spine treated with surgery reported less pain with their sex life compared to patients treated without surgery. This finding lasted throughout the four years of follow-up.”

LAS VEGAS—Chronic low back pain can limit everyday activities, including sex. New research presented at the 2015 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) found that 70% of patients consider sexual activity “relevant” to their quality of life, and patients who receive surgical treatment for spinal degenerative spondylolisthesis (DS) and spinal stenosis (SS) were twice as likely to report no pain during sex.

“Our current research sheds light on the effect that spinal surgery has on a patient’s sex life and begins to describe the impact spinal disease has on this very important aspect of life,” said senior study author Shane Burch, MD, an orthopedic surgeon at the University of California, San Francisco.

Researchers reviewed data from the Spine Patients Outcomes Research Trial (SPORT) of 1,235 patients diagnosed with DS or SS. Patient responses to the question, “In the past week, how has pain affected your sex life?” were used to determine sex-life relevance. Patients selecting the options, “unable to answer” or “does not apply to me,” were placed in the sex-life non-relevant (NR) group. Patients selecting other options were placed into the sex-life relevant (SLR) group. The mean age of patients in the NR and SLR groups were 68 years and 63 years, respectively. Seventy percent of patients were in the SLR group.

There was a higher association of being in the NR group for patients who were female or unmarried, or had a coexisting joint problem or hypertension. At baseline, 40% of SLR patients reported having some level of pain related to sex.

The study included 825 patients, 449 with SS and 376 with DS. A total of 294 patients received nonoperative treatment, and 531 received surgical treatment. The nonoperative patients were more likely to report pain related to sex at all follow-up time frames (from 41% compared to 20%). The percentages remained constant during annual visits at 1 year, 2 years, 3 years, and 4 years after surgery. Prior studies found that 41% of physicians routinely question patients with lumbar disc herniation about sexual problems.

“Our current research has two important findings,” said Dr. Horst. “The first is that sexual activity and sexual function is an important consideration for patients with degenerative spine conditions. The study also shows that sexual function is a more relevant consideration for patients who are married, younger, and male. The second important finding of our study is that patients with degenerative conditions of the spine treated with surgery reported less pain with their sex life compared to patients treated without surgery. This finding lasted throughout the four years of follow-up.”

LAS VEGAS—Chronic low back pain can limit everyday activities, including sex. New research presented at the 2015 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) found that 70% of patients consider sexual activity “relevant” to their quality of life, and patients who receive surgical treatment for spinal degenerative spondylolisthesis (DS) and spinal stenosis (SS) were twice as likely to report no pain during sex.

“Our current research sheds light on the effect that spinal surgery has on a patient’s sex life and begins to describe the impact spinal disease has on this very important aspect of life,” said senior study author Shane Burch, MD, an orthopedic surgeon at the University of California, San Francisco.

Researchers reviewed data from the Spine Patients Outcomes Research Trial (SPORT) of 1,235 patients diagnosed with DS or SS. Patient responses to the question, “In the past week, how has pain affected your sex life?” were used to determine sex-life relevance. Patients selecting the options, “unable to answer” or “does not apply to me,” were placed in the sex-life non-relevant (NR) group. Patients selecting other options were placed into the sex-life relevant (SLR) group. The mean age of patients in the NR and SLR groups were 68 years and 63 years, respectively. Seventy percent of patients were in the SLR group.

There was a higher association of being in the NR group for patients who were female or unmarried, or had a coexisting joint problem or hypertension. At baseline, 40% of SLR patients reported having some level of pain related to sex.

The study included 825 patients, 449 with SS and 376 with DS. A total of 294 patients received nonoperative treatment, and 531 received surgical treatment. The nonoperative patients were more likely to report pain related to sex at all follow-up time frames (from 41% compared to 20%). The percentages remained constant during annual visits at 1 year, 2 years, 3 years, and 4 years after surgery. Prior studies found that 41% of physicians routinely question patients with lumbar disc herniation about sexual problems.

“Our current research has two important findings,” said Dr. Horst. “The first is that sexual activity and sexual function is an important consideration for patients with degenerative spine conditions. The study also shows that sexual function is a more relevant consideration for patients who are married, younger, and male. The second important finding of our study is that patients with degenerative conditions of the spine treated with surgery reported less pain with their sex life compared to patients treated without surgery. This finding lasted throughout the four years of follow-up.”

Osteoid osteoma (OO) is one of the most common benign tumors of bone, representing roughly 10% of all benign bone-forming tumors and 5% of all primary bone tumors.¹ The majority of cases occur in individuals under age 20 years and more frequently in males (2:1).² These lesions tend to be cortically based and most often located about the hip and in the diaphysis of long bones. They typically are characterized radiographically by a nidus less than 2 cm in diameter surrounded by dense, reactive bone of variable thickness.

The classic presentation of OO is localized, dull, aching pain that is worse at night and that is relieved with use of salicylates or other nonsteroidal anti-inflammatory drugs (NSAIDs).³ The diagnosis is made by patient history and plain radiographs, often supported by computed tomography (CT) or magnetic resonance imaging for appropriate identification of the tumor nidus. Despite effective pain relief with NSAIDs as well as evidence suggesting that the natural history of these tumors is self-limited, most patients forgo medical management in favor of elective surgical treatment.^4,5

Initially, treatment for OO focused on either symptom management or en bloc surgical resection of the tumor nidus. Several different minimally invasive therapies have since been developed, and good results reported.^6-8 More recently, use of percutaneous radiofrequency ablation (RFA) has increased, as this method has demonstrated high efficacy and minimal morbidity.^9-11 RFA for OO traditionally has been performed by radiologists under CT guidance in the radiology suite, but advances in intraoperative imaging techniques now allow orthopedic oncologists to perform image-guided RFA in the operating room.

To our knowledge, there have been no reports documenting use of intraoperative CT for localization of OO and use of RFA in the treatment of this lesion. In this article, we report the results of a series of 28 patients with OO treated with intraoperative CT-guided RFA by a single surgeon. We also provide a brief description of this novel technique.

Materials and Methods

The protocol used was approved by our institutional review board. All patients and/or their legal guardians provided informed consent to participate in the study and were informed at the time consent was obtained that case-related data would be submitted for publication.

Patients

Between September 2004 and December 2008, 28 patients (19 males, 9 females) with OO underwent intraoperative percutaneous image-guided RFA at a university hospital. Mean age was 19.5 years, median age was 16 years (range, 7-54 years). Patients were referred for RFA if they had clinical and radiographic features of OO (Figures 1, 2) and wanted to forgo continued medical management. As we selected only patients with lesions that we thought were amenable to percutaneous RFA—lesions involving the long and short bones of the upper or lower extremity and selected flat bones—en bloc surgical resection was not offered to these patients. Lesions were located in the upper extremity (n = 1), lower extremity (n = 24), and pelvis (n = 3) (Figure 3). Twenty-seven procedures were performed for initial tumor treatment and 1 for recurrence after previous open excision. Two additional procedures were later performed on separate patients with recurrent symptoms after the index procedure. All procedures were performed by the senior author (DML).

Procedure

With each patient, all options were discussed, including continued medical management versus surgical treatment, and informed consent was obtained. All procedures were performed with the patient under general anesthesia in the operating room. RFA for an upper extremity lesion was performed with the patient in the supine position with the ipsilateral extremity draped over a hand table. The 2 procedures for lesions in the talus or calcaneus were performed with the patient in the supine position using a standard table with the bottom of the table flexed down 90° to allow the nonaffected leg to hang over the end of the table. The affected extremity in each case was then positioned in a well-padded leg holder to allow the foot and ankle to be draped free for 360° imaging.

All other procedures for lower extremity diaphyseal or pelvic lesions were performed with a fracture table. After successful induction of general anesthesia, the patient was positioned supine on the table with the contralateral lower extremity abducted and externally rotated in a well-leg holder. The ipsilateral leg was held in the traction apparatus without traction applied and was prepared and draped accordingly (Figure 4). With use of the Siemens Siremobil ISO-C3D fluoroscopic C-arm (Siemens Medical Solutions, Malvern, Pennsylvania), a radiograph was taken of the affected area to identify the lesion. Local anesthetic was infiltrated into the surgical site down to the periosteum. A stab incision was made, and, with fluoroscopic guidance, a 0.062-mm Kirschner wire (K-wire) was placed into the lesion. Location within the tumor nidus was confirmed with biplanar fluoroscopic imaging. A Bonopty cannula (AprioMed, Uppsala, Sweden) was then passed over the K-wire. After the wire was removed, a 5-mm radiofrequency probe (Radionics, Burlington, Massachusetts) was placed through the cannula, and positioning within the nidus was confirmed with 3-dimensional (3-D) CT reconstructions in the sagittal, coronal, and axial planes (Figure 5). A radiofrequency generator (Radionics) was used to heat the lesion at 93°C for 7 minutes. The probe and trocar were then removed. Steri-strips and a sterile dressing were used to cover the wound, and the patient was taken to the recovery area after extubation. All patients were discharged home the day of the procedure.

Follow-Up

We phoned all the patients to ask about symptom recurrence, outside treatment, and satisfaction with RFA and to obtain informed consent to participate in our study. Only 1 of the 28 patients could not be reached and was lost to follow-up. Mean follow-up at time of study completion was 31.1 months (range, 5.2-55.8 months).

The 27 patients were asked a series of questions about their treatment: Have you had any recurrence of symptoms following treatment for your OO? Have you received treatment elsewhere? Were you satisfied with your treatment? Would you have the procedure again if you had a recurrence of symptoms?

Primary success was defined as complete pain relief after initial RFA with no evidence of recurrence at time of final follow-up, and secondary success was defined as presence of recurrent symptoms after initial RFA with complete pain relief after a second procedure with no evidence of recurrence.

Results

All RFAs were technically successful with adequate localization of the tumor nidus and subsequent probe placement within the lesion. There were no intraoperative or postoperative complications. All 28 patients were discharged home the day of procedure. Twenty-six patients (92.8%) experienced complete pain relief after primary RFA, had no evidence of recurrence at final follow-up, and denied symptom recurrence at time of study completion.

The other 2 patients reported symptom recurrence after the index treatment (1 proximal femur lesion, 1 distal femur lesion). One of these patients did well initially but had a recurrence about 2 months after the primary RFA; a second RFA provided complete resolution of pain with no evidence of recurrence at time of study completion. In the other patient’s case, intermittent pain persisted for 2 weeks after the primary RFA, and evidence of recurrence was documented 3 months after surgery; a second RFA was performed shortly thereafter, but the patient was subsequently lost to follow-up.

At time of study completion, all 27 patients who had been contacted by phone denied seeking additional treatment elsewhere and stated they would have the procedure again if their symptoms ever recurred.

Discussion

Osteoid osteoma is one of the most common benign tumors of bone. Over the past 2 decades, percutaneous RFA, in comparison with open excision, has emerged as a safe and effective treatment option with minimal patient morbidity.^9-11 RFA traditionally has been performed by radiologists under CT guidance in the radiology suite. However, now orthopedic surgeons can obtain advanced intraoperative imaging beyond standard fluoroscopy. The Siemens Siremobil ISO-C3D fluoroscopic C-arm is an innovative intraoperative imaging device that functions as a standard fluoroscope but also generates 3-D reconstructions of surgical anatomy. The isocentric design and integrated motor unit allow the C-arm to move through a 190º arc while centering its beam directly on the area of interest. This data set is transferred to a computer workstation, where it is reformatted so that CT-quality images are generated in axial, sagittal, and coronal planes. This acquisition process takes only minutes, and the multiplanar images produced may be simultaneously displayed and manipulated on the screen in real time.

One concern about this technology is the amount of radiation exposure for patients, surgeons, and operating room staff. The device measures only radiation time, and the amount of exposure during that time depends on the volume and density of the radiated body. We did not calculate the amount of exposure for this study. Mean exposure time was between 20 and 40 seconds, reflecting the number of attempts required to localize the lesion and the surgeon’s experience with the technique. Although the potential for increased exposure is a valid concern, previous studies using this technology have demonstrated that a similar average exposure time is equivalent to that of standard CT, and that use of the device, over conventional techniques, potentially can lead to decreased overall radiation exposure.^12,13

This series demonstrated that OO can be safely and effectively treated with intraoperative percutaneous RFA by an orthopedic oncologist. Our success rate is very similar to rates reported in the radiology literature. Studies are needed to confirm the efficacy of this novel technique in comparison with what has been reported in that literature. Given these promising preliminary results, and the relative ease of use and minimal learning curve associated with this technology, all orthopedic oncologists should be able to offer this treatment for OO. Furthermore, this technique allows orthopedic oncologists to provide appropriate definitive treatment and care directly, rather than by referring patients to radiologists.

In the treatment of OO, we reserve RFA for lesions involving the long and short bones of the upper and lower extremities, as well as selected flat bones, such as those in the pelvis. Although percutaneous RFA of spinal lesions has been reported in the literature, we think these represent a relative contraindication for this technique; image resolution, in our opinion, is not high enough to justify risking injury to the nerves in the spinal canal, lateral recesses, and neural foramina. In addition, given the radiation exposure, we recommend caution when using this technique for a pelvic or proximal femoral lesion in a woman of childbearing age.

Osteoid osteoma (OO) is one of the most common benign tumors of bone, representing roughly 10% of all benign bone-forming tumors and 5% of all primary bone tumors.¹ The majority of cases occur in individuals under age 20 years and more frequently in males (2:1).² These lesions tend to be cortically based and most often located about the hip and in the diaphysis of long bones. They typically are characterized radiographically by a nidus less than 2 cm in diameter surrounded by dense, reactive bone of variable thickness.

The classic presentation of OO is localized, dull, aching pain that is worse at night and that is relieved with use of salicylates or other nonsteroidal anti-inflammatory drugs (NSAIDs).³ The diagnosis is made by patient history and plain radiographs, often supported by computed tomography (CT) or magnetic resonance imaging for appropriate identification of the tumor nidus. Despite effective pain relief with NSAIDs as well as evidence suggesting that the natural history of these tumors is self-limited, most patients forgo medical management in favor of elective surgical treatment.^4,5

Initially, treatment for OO focused on either symptom management or en bloc surgical resection of the tumor nidus. Several different minimally invasive therapies have since been developed, and good results reported.^6-8 More recently, use of percutaneous radiofrequency ablation (RFA) has increased, as this method has demonstrated high efficacy and minimal morbidity.^9-11 RFA for OO traditionally has been performed by radiologists under CT guidance in the radiology suite, but advances in intraoperative imaging techniques now allow orthopedic oncologists to perform image-guided RFA in the operating room.

To our knowledge, there have been no reports documenting use of intraoperative CT for localization of OO and use of RFA in the treatment of this lesion. In this article, we report the results of a series of 28 patients with OO treated with intraoperative CT-guided RFA by a single surgeon. We also provide a brief description of this novel technique.

Materials and Methods

The protocol used was approved by our institutional review board. All patients and/or their legal guardians provided informed consent to participate in the study and were informed at the time consent was obtained that case-related data would be submitted for publication.

Patients

Between September 2004 and December 2008, 28 patients (19 males, 9 females) with OO underwent intraoperative percutaneous image-guided RFA at a university hospital. Mean age was 19.5 years, median age was 16 years (range, 7-54 years). Patients were referred for RFA if they had clinical and radiographic features of OO (Figures 1, 2) and wanted to forgo continued medical management. As we selected only patients with lesions that we thought were amenable to percutaneous RFA—lesions involving the long and short bones of the upper or lower extremity and selected flat bones—en bloc surgical resection was not offered to these patients. Lesions were located in the upper extremity (n = 1), lower extremity (n = 24), and pelvis (n = 3) (Figure 3). Twenty-seven procedures were performed for initial tumor treatment and 1 for recurrence after previous open excision. Two additional procedures were later performed on separate patients with recurrent symptoms after the index procedure. All procedures were performed by the senior author (DML).

Procedure

With each patient, all options were discussed, including continued medical management versus surgical treatment, and informed consent was obtained. All procedures were performed with the patient under general anesthesia in the operating room. RFA for an upper extremity lesion was performed with the patient in the supine position with the ipsilateral extremity draped over a hand table. The 2 procedures for lesions in the talus or calcaneus were performed with the patient in the supine position using a standard table with the bottom of the table flexed down 90° to allow the nonaffected leg to hang over the end of the table. The affected extremity in each case was then positioned in a well-padded leg holder to allow the foot and ankle to be draped free for 360° imaging.

All other procedures for lower extremity diaphyseal or pelvic lesions were performed with a fracture table. After successful induction of general anesthesia, the patient was positioned supine on the table with the contralateral lower extremity abducted and externally rotated in a well-leg holder. The ipsilateral leg was held in the traction apparatus without traction applied and was prepared and draped accordingly (Figure 4). With use of the Siemens Siremobil ISO-C3D fluoroscopic C-arm (Siemens Medical Solutions, Malvern, Pennsylvania), a radiograph was taken of the affected area to identify the lesion. Local anesthetic was infiltrated into the surgical site down to the periosteum. A stab incision was made, and, with fluoroscopic guidance, a 0.062-mm Kirschner wire (K-wire) was placed into the lesion. Location within the tumor nidus was confirmed with biplanar fluoroscopic imaging. A Bonopty cannula (AprioMed, Uppsala, Sweden) was then passed over the K-wire. After the wire was removed, a 5-mm radiofrequency probe (Radionics, Burlington, Massachusetts) was placed through the cannula, and positioning within the nidus was confirmed with 3-dimensional (3-D) CT reconstructions in the sagittal, coronal, and axial planes (Figure 5). A radiofrequency generator (Radionics) was used to heat the lesion at 93°C for 7 minutes. The probe and trocar were then removed. Steri-strips and a sterile dressing were used to cover the wound, and the patient was taken to the recovery area after extubation. All patients were discharged home the day of the procedure.

Follow-Up

We phoned all the patients to ask about symptom recurrence, outside treatment, and satisfaction with RFA and to obtain informed consent to participate in our study. Only 1 of the 28 patients could not be reached and was lost to follow-up. Mean follow-up at time of study completion was 31.1 months (range, 5.2-55.8 months).

The 27 patients were asked a series of questions about their treatment: Have you had any recurrence of symptoms following treatment for your OO? Have you received treatment elsewhere? Were you satisfied with your treatment? Would you have the procedure again if you had a recurrence of symptoms?

Primary success was defined as complete pain relief after initial RFA with no evidence of recurrence at time of final follow-up, and secondary success was defined as presence of recurrent symptoms after initial RFA with complete pain relief after a second procedure with no evidence of recurrence.

Results

All RFAs were technically successful with adequate localization of the tumor nidus and subsequent probe placement within the lesion. There were no intraoperative or postoperative complications. All 28 patients were discharged home the day of procedure. Twenty-six patients (92.8%) experienced complete pain relief after primary RFA, had no evidence of recurrence at final follow-up, and denied symptom recurrence at time of study completion.

The other 2 patients reported symptom recurrence after the index treatment (1 proximal femur lesion, 1 distal femur lesion). One of these patients did well initially but had a recurrence about 2 months after the primary RFA; a second RFA provided complete resolution of pain with no evidence of recurrence at time of study completion. In the other patient’s case, intermittent pain persisted for 2 weeks after the primary RFA, and evidence of recurrence was documented 3 months after surgery; a second RFA was performed shortly thereafter, but the patient was subsequently lost to follow-up.

At time of study completion, all 27 patients who had been contacted by phone denied seeking additional treatment elsewhere and stated they would have the procedure again if their symptoms ever recurred.

Discussion

Osteoid osteoma is one of the most common benign tumors of bone. Over the past 2 decades, percutaneous RFA, in comparison with open excision, has emerged as a safe and effective treatment option with minimal patient morbidity.^9-11 RFA traditionally has been performed by radiologists under CT guidance in the radiology suite. However, now orthopedic surgeons can obtain advanced intraoperative imaging beyond standard fluoroscopy. The Siemens Siremobil ISO-C3D fluoroscopic C-arm is an innovative intraoperative imaging device that functions as a standard fluoroscope but also generates 3-D reconstructions of surgical anatomy. The isocentric design and integrated motor unit allow the C-arm to move through a 190º arc while centering its beam directly on the area of interest. This data set is transferred to a computer workstation, where it is reformatted so that CT-quality images are generated in axial, sagittal, and coronal planes. This acquisition process takes only minutes, and the multiplanar images produced may be simultaneously displayed and manipulated on the screen in real time.

One concern about this technology is the amount of radiation exposure for patients, surgeons, and operating room staff. The device measures only radiation time, and the amount of exposure during that time depends on the volume and density of the radiated body. We did not calculate the amount of exposure for this study. Mean exposure time was between 20 and 40 seconds, reflecting the number of attempts required to localize the lesion and the surgeon’s experience with the technique. Although the potential for increased exposure is a valid concern, previous studies using this technology have demonstrated that a similar average exposure time is equivalent to that of standard CT, and that use of the device, over conventional techniques, potentially can lead to decreased overall radiation exposure.^12,13

This series demonstrated that OO can be safely and effectively treated with intraoperative percutaneous RFA by an orthopedic oncologist. Our success rate is very similar to rates reported in the radiology literature. Studies are needed to confirm the efficacy of this novel technique in comparison with what has been reported in that literature. Given these promising preliminary results, and the relative ease of use and minimal learning curve associated with this technology, all orthopedic oncologists should be able to offer this treatment for OO. Furthermore, this technique allows orthopedic oncologists to provide appropriate definitive treatment and care directly, rather than by referring patients to radiologists.

In the treatment of OO, we reserve RFA for lesions involving the long and short bones of the upper and lower extremities, as well as selected flat bones, such as those in the pelvis. Although percutaneous RFA of spinal lesions has been reported in the literature, we think these represent a relative contraindication for this technique; image resolution, in our opinion, is not high enough to justify risking injury to the nerves in the spinal canal, lateral recesses, and neural foramina. In addition, given the radiation exposure, we recommend caution when using this technique for a pelvic or proximal femoral lesion in a woman of childbearing age.

Osteoid osteoma (OO) is one of the most common benign tumors of bone, representing roughly 10% of all benign bone-forming tumors and 5% of all primary bone tumors.¹ The majority of cases occur in individuals under age 20 years and more frequently in males (2:1).² These lesions tend to be cortically based and most often located about the hip and in the diaphysis of long bones. They typically are characterized radiographically by a nidus less than 2 cm in diameter surrounded by dense, reactive bone of variable thickness.

The classic presentation of OO is localized, dull, aching pain that is worse at night and that is relieved with use of salicylates or other nonsteroidal anti-inflammatory drugs (NSAIDs).³ The diagnosis is made by patient history and plain radiographs, often supported by computed tomography (CT) or magnetic resonance imaging for appropriate identification of the tumor nidus. Despite effective pain relief with NSAIDs as well as evidence suggesting that the natural history of these tumors is self-limited, most patients forgo medical management in favor of elective surgical treatment.^4,5

Initially, treatment for OO focused on either symptom management or en bloc surgical resection of the tumor nidus. Several different minimally invasive therapies have since been developed, and good results reported.^6-8 More recently, use of percutaneous radiofrequency ablation (RFA) has increased, as this method has demonstrated high efficacy and minimal morbidity.^9-11 RFA for OO traditionally has been performed by radiologists under CT guidance in the radiology suite, but advances in intraoperative imaging techniques now allow orthopedic oncologists to perform image-guided RFA in the operating room.

To our knowledge, there have been no reports documenting use of intraoperative CT for localization of OO and use of RFA in the treatment of this lesion. In this article, we report the results of a series of 28 patients with OO treated with intraoperative CT-guided RFA by a single surgeon. We also provide a brief description of this novel technique.

Materials and Methods

The protocol used was approved by our institutional review board. All patients and/or their legal guardians provided informed consent to participate in the study and were informed at the time consent was obtained that case-related data would be submitted for publication.

Patients

Between September 2004 and December 2008, 28 patients (19 males, 9 females) with OO underwent intraoperative percutaneous image-guided RFA at a university hospital. Mean age was 19.5 years, median age was 16 years (range, 7-54 years). Patients were referred for RFA if they had clinical and radiographic features of OO (Figures 1, 2) and wanted to forgo continued medical management. As we selected only patients with lesions that we thought were amenable to percutaneous RFA—lesions involving the long and short bones of the upper or lower extremity and selected flat bones—en bloc surgical resection was not offered to these patients. Lesions were located in the upper extremity (n = 1), lower extremity (n = 24), and pelvis (n = 3) (Figure 3). Twenty-seven procedures were performed for initial tumor treatment and 1 for recurrence after previous open excision. Two additional procedures were later performed on separate patients with recurrent symptoms after the index procedure. All procedures were performed by the senior author (DML).

Procedure

With each patient, all options were discussed, including continued medical management versus surgical treatment, and informed consent was obtained. All procedures were performed with the patient under general anesthesia in the operating room. RFA for an upper extremity lesion was performed with the patient in the supine position with the ipsilateral extremity draped over a hand table. The 2 procedures for lesions in the talus or calcaneus were performed with the patient in the supine position using a standard table with the bottom of the table flexed down 90° to allow the nonaffected leg to hang over the end of the table. The affected extremity in each case was then positioned in a well-padded leg holder to allow the foot and ankle to be draped free for 360° imaging.

All other procedures for lower extremity diaphyseal or pelvic lesions were performed with a fracture table. After successful induction of general anesthesia, the patient was positioned supine on the table with the contralateral lower extremity abducted and externally rotated in a well-leg holder. The ipsilateral leg was held in the traction apparatus without traction applied and was prepared and draped accordingly (Figure 4). With use of the Siemens Siremobil ISO-C3D fluoroscopic C-arm (Siemens Medical Solutions, Malvern, Pennsylvania), a radiograph was taken of the affected area to identify the lesion. Local anesthetic was infiltrated into the surgical site down to the periosteum. A stab incision was made, and, with fluoroscopic guidance, a 0.062-mm Kirschner wire (K-wire) was placed into the lesion. Location within the tumor nidus was confirmed with biplanar fluoroscopic imaging. A Bonopty cannula (AprioMed, Uppsala, Sweden) was then passed over the K-wire. After the wire was removed, a 5-mm radiofrequency probe (Radionics, Burlington, Massachusetts) was placed through the cannula, and positioning within the nidus was confirmed with 3-dimensional (3-D) CT reconstructions in the sagittal, coronal, and axial planes (Figure 5). A radiofrequency generator (Radionics) was used to heat the lesion at 93°C for 7 minutes. The probe and trocar were then removed. Steri-strips and a sterile dressing were used to cover the wound, and the patient was taken to the recovery area after extubation. All patients were discharged home the day of the procedure.

Follow-Up

We phoned all the patients to ask about symptom recurrence, outside treatment, and satisfaction with RFA and to obtain informed consent to participate in our study. Only 1 of the 28 patients could not be reached and was lost to follow-up. Mean follow-up at time of study completion was 31.1 months (range, 5.2-55.8 months).

The 27 patients were asked a series of questions about their treatment: Have you had any recurrence of symptoms following treatment for your OO? Have you received treatment elsewhere? Were you satisfied with your treatment? Would you have the procedure again if you had a recurrence of symptoms?

Primary success was defined as complete pain relief after initial RFA with no evidence of recurrence at time of final follow-up, and secondary success was defined as presence of recurrent symptoms after initial RFA with complete pain relief after a second procedure with no evidence of recurrence.

Results

All RFAs were technically successful with adequate localization of the tumor nidus and subsequent probe placement within the lesion. There were no intraoperative or postoperative complications. All 28 patients were discharged home the day of procedure. Twenty-six patients (92.8%) experienced complete pain relief after primary RFA, had no evidence of recurrence at final follow-up, and denied symptom recurrence at time of study completion.

The other 2 patients reported symptom recurrence after the index treatment (1 proximal femur lesion, 1 distal femur lesion). One of these patients did well initially but had a recurrence about 2 months after the primary RFA; a second RFA provided complete resolution of pain with no evidence of recurrence at time of study completion. In the other patient’s case, intermittent pain persisted for 2 weeks after the primary RFA, and evidence of recurrence was documented 3 months after surgery; a second RFA was performed shortly thereafter, but the patient was subsequently lost to follow-up.

At time of study completion, all 27 patients who had been contacted by phone denied seeking additional treatment elsewhere and stated they would have the procedure again if their symptoms ever recurred.

Discussion

Osteoid osteoma is one of the most common benign tumors of bone. Over the past 2 decades, percutaneous RFA, in comparison with open excision, has emerged as a safe and effective treatment option with minimal patient morbidity.^9-11 RFA traditionally has been performed by radiologists under CT guidance in the radiology suite. However, now orthopedic surgeons can obtain advanced intraoperative imaging beyond standard fluoroscopy. The Siemens Siremobil ISO-C3D fluoroscopic C-arm is an innovative intraoperative imaging device that functions as a standard fluoroscope but also generates 3-D reconstructions of surgical anatomy. The isocentric design and integrated motor unit allow the C-arm to move through a 190º arc while centering its beam directly on the area of interest. This data set is transferred to a computer workstation, where it is reformatted so that CT-quality images are generated in axial, sagittal, and coronal planes. This acquisition process takes only minutes, and the multiplanar images produced may be simultaneously displayed and manipulated on the screen in real time.

One concern about this technology is the amount of radiation exposure for patients, surgeons, and operating room staff. The device measures only radiation time, and the amount of exposure during that time depends on the volume and density of the radiated body. We did not calculate the amount of exposure for this study. Mean exposure time was between 20 and 40 seconds, reflecting the number of attempts required to localize the lesion and the surgeon’s experience with the technique. Although the potential for increased exposure is a valid concern, previous studies using this technology have demonstrated that a similar average exposure time is equivalent to that of standard CT, and that use of the device, over conventional techniques, potentially can lead to decreased overall radiation exposure.^12,13

This series demonstrated that OO can be safely and effectively treated with intraoperative percutaneous RFA by an orthopedic oncologist. Our success rate is very similar to rates reported in the radiology literature. Studies are needed to confirm the efficacy of this novel technique in comparison with what has been reported in that literature. Given these promising preliminary results, and the relative ease of use and minimal learning curve associated with this technology, all orthopedic oncologists should be able to offer this treatment for OO. Furthermore, this technique allows orthopedic oncologists to provide appropriate definitive treatment and care directly, rather than by referring patients to radiologists.

In the treatment of OO, we reserve RFA for lesions involving the long and short bones of the upper and lower extremities, as well as selected flat bones, such as those in the pelvis. Although percutaneous RFA of spinal lesions has been reported in the literature, we think these represent a relative contraindication for this technique; image resolution, in our opinion, is not high enough to justify risking injury to the nerves in the spinal canal, lateral recesses, and neural foramina. In addition, given the radiation exposure, we recommend caution when using this technique for a pelvic or proximal femoral lesion in a woman of childbearing age.

The accuracy of using computed tomography (CT) to assess lumbar interbody fusion with titanium implants has been questioned in the past.^1-4 Reports have most often focused on older technologies using paired, threaded, smooth-surface titanium devices. Some authors have reported they could not confidently assess the quality of fusions using CT because of implant artifact.^1-3

When pseudarthrosis is suspected clinically, and imaging results are inconclusive, surgical explorations may be performed with mechanical stressing of the segment to assess for motion.^2,5-7 However, surgical exploration not only has the morbidity of another surgery but may not be conclusive. Direct exploration of an interbody fusion is problematic. In some cases, there may be residual normal springing motion through posterior elements, even in the presence of a solid interbody fusion, which can be confusing.⁵ Radiologic confirmation of fusion status is therefore preferred over surgical exploration. CT is the imaging modality used most often to assess spinal fusions.^8,9

A new titanium interbody fusion implant (Endoskeleton TA; Titan Spine, Mequon, Wisconsin) preserves the endplate and has an acid-etched titanium surface for osseous integration and a wide central aperture for bone graft (Figure 1). Compared with earlier titanium implants, this design may allow for more accurate CT imaging and fusion assessment. We conducted a study to determine the interobserver reliability of using CT to evaluate bone formation and other radiographic variables with this new titanium interbody device.

Materials and Methods

After receiving institutional review board approval for this study, as well as patient consent, we obtained and analyzed CT scans of patients after they had undergone anterior lumbar interbody fusion (ALIF) at L3–S1 as part of a separate clinical outcomes study.

Each patient received an Endoskeleton TA implant. The fusion cage was packed with 2 sponges (3.0 mg per fusion level) of bone morphogenetic protein, or BMP (InFuse; Medtronic, Minneapolis, Minnesota). In addition, 1 to 3 cm³ of hydroxyapatite/β-‌tricalcium phosphate (MasterGraft, Medtronic) collagen sponge was used as graft extender to fill any remaining gaps within the cage. Pedicle screw fixation was used in all cases.

Patients were randomly assigned to have fine-cut CT scans with reconstructed images at 6, 9, or 12 months. The scans were reviewed by 2 independent radiologists who were blinded to each other’s interpretations and the clinical results. The radiographic fusion criteria are listed in Tables 1 to 3. Interobserver agreement (κ) was calculated separately for each radiographic criterion and could range from 0.00 (no agreement) to 1.00 (perfect agreement).^10,11

Results

The study involved 33 patients (17 men, 16 women) with 56 lumbar spinal fusion levels. Mean age was 46 years (range, 23-66 years). Six patients (18%) were nicotine users. Seventeen patients were scanned at 6 months, 9 at 9 months, and 7 at 12 months. There were no significant differences in results between men and women, between nicotine users and nonusers, or among patients evaluated at 6, 9, or 12 months.

The radiologists agreed on 345 of the 392 data points reviewed (κ = 0.88). Interobserver agreement results for the fusion criteria are listed in Tables 1 and 3. Interobserver agreement was 0.77 for overall fusion grade, with the radiologists noting definite fusion (grade 5) in 80% and 91% of the levels (Table 1). Other radiographic criteria are listed in Tables 2 and 3. Interobserver agreement was 0.80 for degree of artifact, 0.95 for subsidence, 0.96 for both lucency and trabecular bone, 0.77 for anterior osseous bridging, and 0.95 for cystic vertebral changes.

Discussion

Radiographic analysis of interbody fusions is an important clinical issue. Investigators have shown that CT is the radiographic method of choice for assessing fusion.^8,9 Others have reported that assessing fusion with metallic interbody implants is more difficult compared with PEEK (polyether ether ketone) or allograft bone.^3,4,5,12

Heithoff and colleagues^1,2 reported on difficulties they encountered in assessing interbody fusion with titanium implants, and their research has often been cited. The authors concluded that they could not accurately assess fusion in these cases because of artifact from the small apertures in the cages and metallic scatter. Their study was very small (8 patients, 12 surgical levels) and used paired BAK (Bagby and Kuslich) cages (Zimmer, Warsaw, Indiana).

Recently, a unique surface technology, used to manufacture osseointegrative dental implants, has been adapted for use in the spine.^13-15 Acid etching modifies the surface of titanium to create a nano-scale (micron-level) alteration. Compared with PEEK and smooth titanium, acid-etched titanium stimulates a better osteogenic environment.^16,17 As this technology is now used clinically in spinal surgery, we thought it important to revisit the issue of CT analysis for fusion assessment with the newer titanium implants.

Artifact

The results of our study support the idea that the design of a titanium interbody fusion implant is important to radiographic analysis. The implant studied has a large open central aperture that appears to generate less artifact than historical controls (paired cylindrical cages) have.^1-4 Other investigators have reported fewer problems with artifact in their studies of implants incorporating larger openings for bone graft.^6,18 The radiologists in the present study found no significant problems with artifact. Less artifact is clinically important, as the remaining fusion variables can be more clearly visualized (Table 2, Figure 2).

Anterior Osseous Bridging, Subsidence, Lysis

In this study, the bony endplates were preserved. The disc and endplate cartilage was removed without reaming or drilling. Endplate reaming most likely contributes to subsidence and loss of original fixation between implant and bone interface.^1,4,12 Some authors have advocated recessing the cages deeply and then packing bone anteriorly to create a “sentinel fusion sign.”^1,2,6 Deeply seating interbody implants, instead of resting them more widely on the apophyseal ring of the vertebral endplate, may also lead to subsidence.^4,12 The issue of identifying a sentinel fusion sign is relevant only if the surgeon tries to create one. In the present study, the implant used was an impacted cage positioned on the apophyseal perimeter of the disc space, just slightly recessed, so there was no attempt to create a sentinel fusion sign, as reflected in the relatively low scores on anterior osseous bridging (48%, 52%).

Subsidence and peri-implant lysis are pathologic variables associated with motion and bone loss. Sethi and colleagues¹⁹ noted a high percentage of endplate resorption and subsidence in cases reviewed using PEEK or allograft spacers paired with BMP-2. Although BMP-2 was used in the present study, we found very low rates of subsidence (0%, 5%) and no significant peri-implant lucencies (2%, 4%) (Figure 2). Interobserver agreement for these variables was high (0.95, 0.96). We hypothesize that the combination of endplate-sparing surgical technique and implant–bone integration contributed to these results.

Trabecular Bone and Fusion Grade

The primary radiographic criterion for solid interbody fusion is trabecular bone throughout the cage, bridging the vertebral bodies. In our study, the success rates for this variable were 96% and 100%, and there was very high interobserver agreement (0.96) (Figure 3). This very high fusion rate may preclude detecting subtle differences in interobserver agreement, but to what degree, if any, is unknown. Other investigators have effectively identified trabecular bone across the interspace and throughout the cages.^6,18 The openings for bone formation were larger in the implants they used than in first-generation fusion cages but not as large as the implant openings in the present study. Larger openings may correlate with improved ability to visualize bridging bone on CT.

Radiologists and surgeons must ultimately arrive at a conclusion regarding the likelihood a fusion has occurred. Our radiologists integrated all the separate radiologic variables cited here, as well as their overall impressions of the scans, to arrive at a final grade regarding fusion quality (Figures 3, 4). Although this category provides the most interpretive latitude of all the variables examined, the results demonstrate high interobserver reliability. Agreement to exactly the same fusion grade was 0.77, and agreement to within 1 category grade was 0.95.

This study had several limitations. Surgical explorations were not clinically indicated and were not performed. There were no suspected nonunions or hardware complications, two of the most common indications for exploration. In addition, this study was conducted not to determine specific accuracy of CT (compared with surgery exploration) for fusion assessment but to assess interobserver reliability. The clinical success rates for this population were high, and no patient required revision surgery for suspected pseudarthrosis. To assess the true accuracy of CT for fusion assessment, one would have to subject patients to follow-up exploratory surgery to test fusions mechanically.

Another limitation is the lack of a single industry-accepted radiographic fusion grading system. Fusion criteria are not standardized across all studies. Our radiologists have extensive research experience and limit their practices to neuromuscular radiology with a concentration on the spine. The radiographic criteria cited here are the same criteria they use in clinical practice, when reviewing CT scans for clinicians. Last, there was no control group for direct comparison against other cages. Historical controls were cited. This does not adversely affect the conclusions of this investigation.

Conclusion

Clinicians have been reluctant to rely on CT with titanium devices because of concerns about the accuracy of image interpretations. The interbody device used in this study demonstrated minimal artifact and minimal subsidence, and trabecular bone was easily identified throughout the implant in the majority of cases reviewed. We found high interobserver agreement scores across all fusion criteria. Although surgical exploration remains the gold standard for fusion assessment, surgeons should have confidence in using CT with this titanium implant.

The accuracy of using computed tomography (CT) to assess lumbar interbody fusion with titanium implants has been questioned in the past.^1-4 Reports have most often focused on older technologies using paired, threaded, smooth-surface titanium devices. Some authors have reported they could not confidently assess the quality of fusions using CT because of implant artifact.^1-3

When pseudarthrosis is suspected clinically, and imaging results are inconclusive, surgical explorations may be performed with mechanical stressing of the segment to assess for motion.^2,5-7 However, surgical exploration not only has the morbidity of another surgery but may not be conclusive. Direct exploration of an interbody fusion is problematic. In some cases, there may be residual normal springing motion through posterior elements, even in the presence of a solid interbody fusion, which can be confusing.⁵ Radiologic confirmation of fusion status is therefore preferred over surgical exploration. CT is the imaging modality used most often to assess spinal fusions.^8,9

A new titanium interbody fusion implant (Endoskeleton TA; Titan Spine, Mequon, Wisconsin) preserves the endplate and has an acid-etched titanium surface for osseous integration and a wide central aperture for bone graft (Figure 1). Compared with earlier titanium implants, this design may allow for more accurate CT imaging and fusion assessment. We conducted a study to determine the interobserver reliability of using CT to evaluate bone formation and other radiographic variables with this new titanium interbody device.

Materials and Methods

After receiving institutional review board approval for this study, as well as patient consent, we obtained and analyzed CT scans of patients after they had undergone anterior lumbar interbody fusion (ALIF) at L3–S1 as part of a separate clinical outcomes study.

Each patient received an Endoskeleton TA implant. The fusion cage was packed with 2 sponges (3.0 mg per fusion level) of bone morphogenetic protein, or BMP (InFuse; Medtronic, Minneapolis, Minnesota). In addition, 1 to 3 cm³ of hydroxyapatite/β-‌tricalcium phosphate (MasterGraft, Medtronic) collagen sponge was used as graft extender to fill any remaining gaps within the cage. Pedicle screw fixation was used in all cases.

Patients were randomly assigned to have fine-cut CT scans with reconstructed images at 6, 9, or 12 months. The scans were reviewed by 2 independent radiologists who were blinded to each other’s interpretations and the clinical results. The radiographic fusion criteria are listed in Tables 1 to 3. Interobserver agreement (κ) was calculated separately for each radiographic criterion and could range from 0.00 (no agreement) to 1.00 (perfect agreement).^10,11

Results

The study involved 33 patients (17 men, 16 women) with 56 lumbar spinal fusion levels. Mean age was 46 years (range, 23-66 years). Six patients (18%) were nicotine users. Seventeen patients were scanned at 6 months, 9 at 9 months, and 7 at 12 months. There were no significant differences in results between men and women, between nicotine users and nonusers, or among patients evaluated at 6, 9, or 12 months.

The radiologists agreed on 345 of the 392 data points reviewed (κ = 0.88). Interobserver agreement results for the fusion criteria are listed in Tables 1 and 3. Interobserver agreement was 0.77 for overall fusion grade, with the radiologists noting definite fusion (grade 5) in 80% and 91% of the levels (Table 1). Other radiographic criteria are listed in Tables 2 and 3. Interobserver agreement was 0.80 for degree of artifact, 0.95 for subsidence, 0.96 for both lucency and trabecular bone, 0.77 for anterior osseous bridging, and 0.95 for cystic vertebral changes.

Discussion

Radiographic analysis of interbody fusions is an important clinical issue. Investigators have shown that CT is the radiographic method of choice for assessing fusion.^8,9 Others have reported that assessing fusion with metallic interbody implants is more difficult compared with PEEK (polyether ether ketone) or allograft bone.^3,4,5,12

Heithoff and colleagues^1,2 reported on difficulties they encountered in assessing interbody fusion with titanium implants, and their research has often been cited. The authors concluded that they could not accurately assess fusion in these cases because of artifact from the small apertures in the cages and metallic scatter. Their study was very small (8 patients, 12 surgical levels) and used paired BAK (Bagby and Kuslich) cages (Zimmer, Warsaw, Indiana).

Recently, a unique surface technology, used to manufacture osseointegrative dental implants, has been adapted for use in the spine.^13-15 Acid etching modifies the surface of titanium to create a nano-scale (micron-level) alteration. Compared with PEEK and smooth titanium, acid-etched titanium stimulates a better osteogenic environment.^16,17 As this technology is now used clinically in spinal surgery, we thought it important to revisit the issue of CT analysis for fusion assessment with the newer titanium implants.

Artifact

The results of our study support the idea that the design of a titanium interbody fusion implant is important to radiographic analysis. The implant studied has a large open central aperture that appears to generate less artifact than historical controls (paired cylindrical cages) have.^1-4 Other investigators have reported fewer problems with artifact in their studies of implants incorporating larger openings for bone graft.^6,18 The radiologists in the present study found no significant problems with artifact. Less artifact is clinically important, as the remaining fusion variables can be more clearly visualized (Table 2, Figure 2).

Anterior Osseous Bridging, Subsidence, Lysis

In this study, the bony endplates were preserved. The disc and endplate cartilage was removed without reaming or drilling. Endplate reaming most likely contributes to subsidence and loss of original fixation between implant and bone interface.^1,4,12 Some authors have advocated recessing the cages deeply and then packing bone anteriorly to create a “sentinel fusion sign.”^1,2,6 Deeply seating interbody implants, instead of resting them more widely on the apophyseal ring of the vertebral endplate, may also lead to subsidence.^4,12 The issue of identifying a sentinel fusion sign is relevant only if the surgeon tries to create one. In the present study, the implant used was an impacted cage positioned on the apophyseal perimeter of the disc space, just slightly recessed, so there was no attempt to create a sentinel fusion sign, as reflected in the relatively low scores on anterior osseous bridging (48%, 52%).

Subsidence and peri-implant lysis are pathologic variables associated with motion and bone loss. Sethi and colleagues¹⁹ noted a high percentage of endplate resorption and subsidence in cases reviewed using PEEK or allograft spacers paired with BMP-2. Although BMP-2 was used in the present study, we found very low rates of subsidence (0%, 5%) and no significant peri-implant lucencies (2%, 4%) (Figure 2). Interobserver agreement for these variables was high (0.95, 0.96). We hypothesize that the combination of endplate-sparing surgical technique and implant–bone integration contributed to these results.

Trabecular Bone and Fusion Grade

The primary radiographic criterion for solid interbody fusion is trabecular bone throughout the cage, bridging the vertebral bodies. In our study, the success rates for this variable were 96% and 100%, and there was very high interobserver agreement (0.96) (Figure 3). This very high fusion rate may preclude detecting subtle differences in interobserver agreement, but to what degree, if any, is unknown. Other investigators have effectively identified trabecular bone across the interspace and throughout the cages.^6,18 The openings for bone formation were larger in the implants they used than in first-generation fusion cages but not as large as the implant openings in the present study. Larger openings may correlate with improved ability to visualize bridging bone on CT.

Radiologists and surgeons must ultimately arrive at a conclusion regarding the likelihood a fusion has occurred. Our radiologists integrated all the separate radiologic variables cited here, as well as their overall impressions of the scans, to arrive at a final grade regarding fusion quality (Figures 3, 4). Although this category provides the most interpretive latitude of all the variables examined, the results demonstrate high interobserver reliability. Agreement to exactly the same fusion grade was 0.77, and agreement to within 1 category grade was 0.95.

This study had several limitations. Surgical explorations were not clinically indicated and were not performed. There were no suspected nonunions or hardware complications, two of the most common indications for exploration. In addition, this study was conducted not to determine specific accuracy of CT (compared with surgery exploration) for fusion assessment but to assess interobserver reliability. The clinical success rates for this population were high, and no patient required revision surgery for suspected pseudarthrosis. To assess the true accuracy of CT for fusion assessment, one would have to subject patients to follow-up exploratory surgery to test fusions mechanically.

Another limitation is the lack of a single industry-accepted radiographic fusion grading system. Fusion criteria are not standardized across all studies. Our radiologists have extensive research experience and limit their practices to neuromuscular radiology with a concentration on the spine. The radiographic criteria cited here are the same criteria they use in clinical practice, when reviewing CT scans for clinicians. Last, there was no control group for direct comparison against other cages. Historical controls were cited. This does not adversely affect the conclusions of this investigation.

Conclusion

Clinicians have been reluctant to rely on CT with titanium devices because of concerns about the accuracy of image interpretations. The interbody device used in this study demonstrated minimal artifact and minimal subsidence, and trabecular bone was easily identified throughout the implant in the majority of cases reviewed. We found high interobserver agreement scores across all fusion criteria. Although surgical exploration remains the gold standard for fusion assessment, surgeons should have confidence in using CT with this titanium implant.

The accuracy of using computed tomography (CT) to assess lumbar interbody fusion with titanium implants has been questioned in the past.^1-4 Reports have most often focused on older technologies using paired, threaded, smooth-surface titanium devices. Some authors have reported they could not confidently assess the quality of fusions using CT because of implant artifact.^1-3

When pseudarthrosis is suspected clinically, and imaging results are inconclusive, surgical explorations may be performed with mechanical stressing of the segment to assess for motion.^2,5-7 However, surgical exploration not only has the morbidity of another surgery but may not be conclusive. Direct exploration of an interbody fusion is problematic. In some cases, there may be residual normal springing motion through posterior elements, even in the presence of a solid interbody fusion, which can be confusing.⁵ Radiologic confirmation of fusion status is therefore preferred over surgical exploration. CT is the imaging modality used most often to assess spinal fusions.^8,9

A new titanium interbody fusion implant (Endoskeleton TA; Titan Spine, Mequon, Wisconsin) preserves the endplate and has an acid-etched titanium surface for osseous integration and a wide central aperture for bone graft (Figure 1). Compared with earlier titanium implants, this design may allow for more accurate CT imaging and fusion assessment. We conducted a study to determine the interobserver reliability of using CT to evaluate bone formation and other radiographic variables with this new titanium interbody device.

Materials and Methods

After receiving institutional review board approval for this study, as well as patient consent, we obtained and analyzed CT scans of patients after they had undergone anterior lumbar interbody fusion (ALIF) at L3–S1 as part of a separate clinical outcomes study.

Each patient received an Endoskeleton TA implant. The fusion cage was packed with 2 sponges (3.0 mg per fusion level) of bone morphogenetic protein, or BMP (InFuse; Medtronic, Minneapolis, Minnesota). In addition, 1 to 3 cm³ of hydroxyapatite/β-‌tricalcium phosphate (MasterGraft, Medtronic) collagen sponge was used as graft extender to fill any remaining gaps within the cage. Pedicle screw fixation was used in all cases.

Patients were randomly assigned to have fine-cut CT scans with reconstructed images at 6, 9, or 12 months. The scans were reviewed by 2 independent radiologists who were blinded to each other’s interpretations and the clinical results. The radiographic fusion criteria are listed in Tables 1 to 3. Interobserver agreement (κ) was calculated separately for each radiographic criterion and could range from 0.00 (no agreement) to 1.00 (perfect agreement).^10,11

Results

The study involved 33 patients (17 men, 16 women) with 56 lumbar spinal fusion levels. Mean age was 46 years (range, 23-66 years). Six patients (18%) were nicotine users. Seventeen patients were scanned at 6 months, 9 at 9 months, and 7 at 12 months. There were no significant differences in results between men and women, between nicotine users and nonusers, or among patients evaluated at 6, 9, or 12 months.

The radiologists agreed on 345 of the 392 data points reviewed (κ = 0.88). Interobserver agreement results for the fusion criteria are listed in Tables 1 and 3. Interobserver agreement was 0.77 for overall fusion grade, with the radiologists noting definite fusion (grade 5) in 80% and 91% of the levels (Table 1). Other radiographic criteria are listed in Tables 2 and 3. Interobserver agreement was 0.80 for degree of artifact, 0.95 for subsidence, 0.96 for both lucency and trabecular bone, 0.77 for anterior osseous bridging, and 0.95 for cystic vertebral changes.

Discussion

Radiographic analysis of interbody fusions is an important clinical issue. Investigators have shown that CT is the radiographic method of choice for assessing fusion.^8,9 Others have reported that assessing fusion with metallic interbody implants is more difficult compared with PEEK (polyether ether ketone) or allograft bone.^3,4,5,12

Heithoff and colleagues^1,2 reported on difficulties they encountered in assessing interbody fusion with titanium implants, and their research has often been cited. The authors concluded that they could not accurately assess fusion in these cases because of artifact from the small apertures in the cages and metallic scatter. Their study was very small (8 patients, 12 surgical levels) and used paired BAK (Bagby and Kuslich) cages (Zimmer, Warsaw, Indiana).

Recently, a unique surface technology, used to manufacture osseointegrative dental implants, has been adapted for use in the spine.^13-15 Acid etching modifies the surface of titanium to create a nano-scale (micron-level) alteration. Compared with PEEK and smooth titanium, acid-etched titanium stimulates a better osteogenic environment.^16,17 As this technology is now used clinically in spinal surgery, we thought it important to revisit the issue of CT analysis for fusion assessment with the newer titanium implants.

Artifact

The results of our study support the idea that the design of a titanium interbody fusion implant is important to radiographic analysis. The implant studied has a large open central aperture that appears to generate less artifact than historical controls (paired cylindrical cages) have.^1-4 Other investigators have reported fewer problems with artifact in their studies of implants incorporating larger openings for bone graft.^6,18 The radiologists in the present study found no significant problems with artifact. Less artifact is clinically important, as the remaining fusion variables can be more clearly visualized (Table 2, Figure 2).

Anterior Osseous Bridging, Subsidence, Lysis

In this study, the bony endplates were preserved. The disc and endplate cartilage was removed without reaming or drilling. Endplate reaming most likely contributes to subsidence and loss of original fixation between implant and bone interface.^1,4,12 Some authors have advocated recessing the cages deeply and then packing bone anteriorly to create a “sentinel fusion sign.”^1,2,6 Deeply seating interbody implants, instead of resting them more widely on the apophyseal ring of the vertebral endplate, may also lead to subsidence.^4,12 The issue of identifying a sentinel fusion sign is relevant only if the surgeon tries to create one. In the present study, the implant used was an impacted cage positioned on the apophyseal perimeter of the disc space, just slightly recessed, so there was no attempt to create a sentinel fusion sign, as reflected in the relatively low scores on anterior osseous bridging (48%, 52%).

Subsidence and peri-implant lysis are pathologic variables associated with motion and bone loss. Sethi and colleagues¹⁹ noted a high percentage of endplate resorption and subsidence in cases reviewed using PEEK or allograft spacers paired with BMP-2. Although BMP-2 was used in the present study, we found very low rates of subsidence (0%, 5%) and no significant peri-implant lucencies (2%, 4%) (Figure 2). Interobserver agreement for these variables was high (0.95, 0.96). We hypothesize that the combination of endplate-sparing surgical technique and implant–bone integration contributed to these results.

Trabecular Bone and Fusion Grade

The primary radiographic criterion for solid interbody fusion is trabecular bone throughout the cage, bridging the vertebral bodies. In our study, the success rates for this variable were 96% and 100%, and there was very high interobserver agreement (0.96) (Figure 3). This very high fusion rate may preclude detecting subtle differences in interobserver agreement, but to what degree, if any, is unknown. Other investigators have effectively identified trabecular bone across the interspace and throughout the cages.^6,18 The openings for bone formation were larger in the implants they used than in first-generation fusion cages but not as large as the implant openings in the present study. Larger openings may correlate with improved ability to visualize bridging bone on CT.

Radiologists and surgeons must ultimately arrive at a conclusion regarding the likelihood a fusion has occurred. Our radiologists integrated all the separate radiologic variables cited here, as well as their overall impressions of the scans, to arrive at a final grade regarding fusion quality (Figures 3, 4). Although this category provides the most interpretive latitude of all the variables examined, the results demonstrate high interobserver reliability. Agreement to exactly the same fusion grade was 0.77, and agreement to within 1 category grade was 0.95.

This study had several limitations. Surgical explorations were not clinically indicated and were not performed. There were no suspected nonunions or hardware complications, two of the most common indications for exploration. In addition, this study was conducted not to determine specific accuracy of CT (compared with surgery exploration) for fusion assessment but to assess interobserver reliability. The clinical success rates for this population were high, and no patient required revision surgery for suspected pseudarthrosis. To assess the true accuracy of CT for fusion assessment, one would have to subject patients to follow-up exploratory surgery to test fusions mechanically.

Another limitation is the lack of a single industry-accepted radiographic fusion grading system. Fusion criteria are not standardized across all studies. Our radiologists have extensive research experience and limit their practices to neuromuscular radiology with a concentration on the spine. The radiographic criteria cited here are the same criteria they use in clinical practice, when reviewing CT scans for clinicians. Last, there was no control group for direct comparison against other cages. Historical controls were cited. This does not adversely affect the conclusions of this investigation.

Conclusion

Clinicians have been reluctant to rely on CT with titanium devices because of concerns about the accuracy of image interpretations. The interbody device used in this study demonstrated minimal artifact and minimal subsidence, and trabecular bone was easily identified throughout the implant in the majority of cases reviewed. We found high interobserver agreement scores across all fusion criteria. Although surgical exploration remains the gold standard for fusion assessment, surgeons should have confidence in using CT with this titanium implant.

The goal of surgical treatment of adolescent idiopathic scoliosis (AIS) is to prevent disability associated with curve progression.¹ Early studies tended to focus on radiographic measures, such as curve correction and sagittal balance, rather than on improvements in quality of life (QOL).^2-5 Although studies have reported on QOL in patients treated surgically for scoliosis,^6-11 these studies were largely limited by small sample size and inclusion of patients with congenital and neuromuscular scoliosis,⁹ lack of a generic measure of QOL,^6,7 or lack of surgical treatment of patients in the cohort.¹⁰

We conducted a study to determine disease-specific and general health-related QOL (HR-QOL) in young adults who underwent surgical correction of their spinal deformity during adolescence and to evaluate associated complications and reoperations.

Materials and Methods

After obtaining institutional review board approval, we queried the surgical database of a large metropolitan tertiary referral center for consecutive patients who had undergone spine deformity correction between the ages of 10 and 17 years (January 1993–December 2003). Hospital and medical records were retrospectively reviewed to confirm the diagnosis of AIS. Patients with congenital, neuromuscular, juvenile, or infantile scoliosis were excluded. Patients with intraspinal pathology (eg, tethered cord, syringomyelia), developmental delay, chromosomal abnormality, or congenital heart disease were also excluded. Patients were contacted by mail or telephone, and the Scoliosis Research Society–22R (SRS-22R)^12-15 and the Short Form–12 (SF-12)¹⁶ were administered. Standard demographic and surgical data were also collected.

The SRS-22R is a scoliosis-specific HR-QOL questionnaire with 22 items, 5 domains (pain, activity, appearance, mental, satisfaction), and a total score.^12-15 Each domain score ranges from 1 to 5 (higher scores indicating better outcomes). The SRS-22R is the outcome instrument most widely used to measure HR-QOL changes in patients with scoliosis, and it is available in several languages.^17-26

The SF-12, a 12-item self-administered short-form health status survey developed in the Medical Outcomes Study, measures patient-based health status. Two composite scores can be calculated: physical composite summary (PCS) and mental composite summary (MCS).¹⁶ Using norm-based scoring, all domain scales have a mean (SD) of 50 (10) based on the general 1998 US population. Thus, scores under 50 fall below the general population mean.

In addition, patients were surveyed to determine the incidence of spine-related symptoms and complaints, including activity limitations, rib prominence, waistline asymmetry, back pain, limited range of motion (ROM), shortness of breath, wound/scar problems, lung disease/asthma, heart disease, high blood pressure, and arthritis. Data regarding postoperative treatment regimens of physical therapy, narcotic pain medication, spinal/epidural injections, and nonsteroidal anti-inflammatory drug (NSAID) use were collected. Patients were also queried regarding their current working status and smoking status.

Standard demographic and surgical data were collected from hospital and office charts and radiographs. Data collected included history of bracing, age at index surgery, number of levels fused, surgical approach (anterior, posterior, combined), postoperative complications (eg, ileus, wound infection, anemia, pneumonia), and immediate preoperative and final postoperative radiographic measures. Data on need for subsequent revision surgery and indications for revision surgery were also collected.

Preoperative and latest follow-up radiographs were measured to determine curve magnitude, sagittal and coronal balance, and percentage curve correction. Coronal balance was defined as the distance between a plumb line drawn vertically from the spinous process of C7 and the central sacral line on full-length posteroanterior radiographs. Sagittal balance was defined as the distance of a plumb line drawn vertically from the center of the body of C7 and the posterosuperior endplate of S1.²⁷

Regression analysis was performed to identify factors predictive of SRS-22R total scores. Factors included in the analysis were sex, age at surgery, Lenke type, surgery type (anterior, posterior, anteroposterior), number of levels fused, lowest instrumented vertebra, perioperative complications, percentage curve correction, postoperative coronal and sagittal balance, smoking status, and need for revision surgery. Although age and sex were considered variables outside the surgeon’s control, they were included in the model, as previous studies have shown that SRS scores varied by age and sex both in adolescents²⁸ and adults.²⁹ Significance was set at P < .01. All data analysis was performed with IBM SPSS Version 19.0 (Somers, New York).

Results

Of the 384 postoperative patients identified for study inclusion, 134 (35%) completed surveys. Sixteen patients with nonidiopathic scoliosis were excluded, leaving 118 available for analysis. Of the remaining patients, 248 (64%) could not be contacted because of a change in address or phone number. Two patients (1%) were unwilling to complete survey requests. There was no statistically significant difference in demographics between patients with and without follow-up data available. Demographics are summarized in Table 1. There were 109 females (92%). Mean (SD) age at surgery was 14.1 (1.9) years. Only 37 (31%) were braced before surgery. Table 2 summarizes the radiographic data. Mean (SD) major Cobb angle was 49.7° (7.8°). Eighty-five patients (72%) underwent posterior fusion with instrumentation using hooks only; another 16 (14%) had anterior-only surgery, and another 17 (14%) had combined anterior-posterior surgery. A mean of 7.8 levels were fused. Index surgery data and lowest instrumented vertebra distribution are summarized in Table 3. Mean (SD) percentage curve correction was 48.9% (8.4%).

Seven patients had a total of 8 perioperative complications: anemia requiring transfusion (2), ileus necessitating nasogastric tube insertion (2), superficial wound infection treated with oral antibiotics and local wound care (2), wound drainage and erythema (1), and pneumonia (1). Mean (SD) length of clinical and radiographic follow-up was 57.9 (36.3) months.

Table 4 summarizes the long-term complications. Of the 38 patients with long-term complications, 14 required reoperation. The indications were disc herniation (2 patients), painful instrumentation (7), crankshaft phenomenon (1), nonunion (1), and adjacent-level degeneration (3). Both disc herniations were at L5–S1, several segments below the distal extent of the fusion. Of the 7 patients who had painful instrumentation removed, 6 had the entire construct removed, and 1 had the proximal half of a rod taken out. The 3 patients with adjacent-level degeneration had stenosis at the distal end of the construct—at L5–S1 (2 patients) or L2–L3 (1 patient).

Mean (SD) time between surgery and completion of the surveys/questionnaires was 12.7 (3.2) years (range, 10-18 years). Mean age of respondents was 26.8 years. Twenty-five respondents (21%) were smokers. Mean (SD) outcome scores were 50.9 (9.4) for SF-12 PCS and 49.4 (10.2) for SF-12 MCS. Eighteen patients (15%) had SF-12 PCS scores 1 SD below normal, and 15 (13%) had SF-12 MCS scores 1 SD below normal. Mean (SD) SRS-22R Total score was 4.0 (0.7). Means, standard deviations, and distribution of SRS domain scores are summarized in Table 5. Of the variables, only current smoking (P < .001) was predictive of SRS-22R Total scores, accounting for 20% of their variability (Table 6).

One hundred patients (85%) had jobs, mostly desk jobs. The postoperative limitations most commonly reported are summarized in Table 7. These included at least intermittent back pain in 90 patients (76%), limited ROM in 52 (44%), and activity limitations in 54 (46%). Less common limitations were waistline imbalance in 41 (35%), rib prominence in 28 (24%), wound/scar problems in 18 (15%), and shortness of breath in 18 (15%). Other related medical problems were lung disease/asthma in 11 (9%), osteoarthritis/degenerative arthritis in 11 (9%), heart disease in 3 (3%), and high blood pressure in 2 (2%).

A minority of patients also participated in postoperative treatment regimens. The most common treatment was regular use of NSAIDs (25 patients, 21%). Other treatments were physical therapy (14, 12%), narcotic pain medication use (5, 4%), and epidural steroid injections (5, 4%). Table 8 summarizes the postoperative treatments used by patients with scoliosis.

Discussion

A major concern about prophylactic interventions for diseases is that the treatment will harm the patient. This is especially true for major spine surgery performed on adolescents with minimal symptoms. Although the incidence of perioperative complications in children undergoing corrective spinal surgery for AIS has been reported,^30-32 the effect of the surgery on the disease-specific HR-QOL outcomes of these individuals as young adults has not been previously studied. Over the past few decades, a paradigm shift in understanding health and disability has occurred, with increased emphasis being placed on HR-QOL outcomes measures and understanding disability as relating to a measureable impact of the functioning of an individual after a change in health or environment. This change was substantiated when the World Health Organization endorsed the International Classification of Functioning, Disability and Health.³³ In light of this shift, we present the disease-specific and general HR-QOL outcomes of young adults who had undergone surgical correction for spinal deformity during adolescence, as well as their associated complications and reoperations, in an attempt to identify targets for improvement.

Our patient-reported outcomes demonstrated a high incidence of occasional back pain, activity-related complaints, and limited ROM. Comparison of our cohort’s SRS-22R outcomes with previously published normative values for the unaffected adolescent population^28,34 suggests worse scores for the disease-specific SRS-22R domains of pain and appearance. In 2012, Daubs and colleagues³⁴ reported that normative scores on various SRS-22 domains were statistically lower with age (scores decreased from age 10 to age 19 years). Both Verma and colleagues²⁸ and Daubs and colleagues³⁴ reported lower scores for females than for males. Therefore, it is unclear whether the differences observed in our cohort may be accounted for by the larger proportion of females compared with the normative data.

General health scores on the SF-12 were similar to the population norm (mean [SD]) of 50 (10) referenced by Ware and colleagues.¹⁶ These findings suggest that, though pain and appearance may be statistically lower in our cohort—as measured with the SRS-22R—the cohort’s spine-related symptoms do not seem to lower its general health. Eighty-five percent of the patients were working at the time of the survey, further supporting a relatively normal level of overall function. In a retrospective review by Takayama and colleagues,⁹ similar results were found with regard to working after AIS fusion surgery. Of 32 patients treated surgically for scoliosis, at a mean of 21.1 years after the index fusion 27 (84.4%) were or had been engaged in various occupations without marked difficulty.

Our results in a cohort of patients with segmental instrumentation using hooks are similar to results in other studies of long-term HR-QOL measures in patients with AIS and Harrington rod instrumentation. Danielsson and Nachemson³⁵ evaluated patients with surgically treated AIS with at least 20-year follow-up and reported that, in their surgical cohort with a mean age of 39.7 years, mean SF-36 PCS score was 50.9, and mean SF-36 MCS score was 50.2. In a recent study of patients with AIS and Harrington rod instrumentation, those of a mean age of 32.3 years had a mean score of 50.9 for both SF-36 PCS and SF-36 MCS.³⁶

Regression analysis identified only smoking as a predictor of SRS-22R Total scores. This finding, that smokers have a lower health state, is expected even in the general population.³⁷ Interestingly, bracing before surgery, Lenke type, surgery type, number of levels fused, lowest instrumented vertebra, incidence of perioperative complications, percentage curve correction, postoperative sagittal and coronal balance, and need for revision surgery did not influence HR-QOL measures in this cohort.

Our cohort’s incidence of occasional back pain was 76% (90/118 patients). Other reports have had similar findings. In 2012, Bas and colleagues³⁸ studied self-reported pain in 126 consecutive patients with scoliosis and instrumented fusion. In their cohort, “most participants reported ‘no pain’ (38.5%) or ‘mild pain’ (30.8%) and 72.1% of participants reported a current work/school activity level of 100% normal.” Also in 2012, Rushton and Grevitt³⁹ reported on a review and statistical analysis of the literature on HR-QOL in adolescents with untreated AIS and in unaffected adolescents. Their goal was to identify whether there were any differences in HR-QOL and, if so, whether they were clinically relevant. The authors concluded that pain and self-image tended to be statistically lower among cohorts with AIS but that only self-image was consistently different clinically between untreated patients with AIS and their unaffected peers.

Cosmetic complaints, though less common than functional concerns, affected a substantial percentage of our cohort. Waistline imbalance complaints were more common than rib prominence or scar-related complaints. The validity of patient-reported waistline imbalance is not known but may contribute to the SRS-22R outcomes in this cohort, particularly with regard to appearance scores. Respiratory symptoms, particularly those related to shortness of breath, were reported by 15% of patients. Respiratory symptoms may be in part secondary to underlying lung disease; smoking was reported by 21% of patients and asthma by 9%.

Few additional postoperative treatments were reported by patients. The most common treatment was regular use of NSAIDs (21%), followed by postoperative physical therapy (12%). Opiate medication use and spinal injections were rare—consistent with results reported by Danielsson and Nachemson³⁵ in 2003.

Implant-related complaints, including painful instrumentation (13%) and implant prominence (9%), were some of the most common complaints in our study group. Although not all symptomatic instrumentation required surgical revision, 7 (50%) of the 14 additional spine surgeries were related to painful and/or prominent posterior instrumentation. Additional spine surgery was reported in 11.9% of our patients. Other indications for reoperation were disc herniation, crankshaft phenomenon, nonunion, and adjacent-level degeneration. Our rate of revision surgery is supported by the literature. In 2009, Luhmann and colleagues⁴⁰ reported that 41 (3.9%) of 1057 primary spine fusions for idiopathic scoliosis required reoperation; the indications included infection (16/1057, 1.5%), pseudarthrosis (12, 1.1%), and painful/prominent implant (7, 0.7%). Richards and colleagues⁴¹ similarly reported on 1046 patients who underwent fusion for AIS. Of these patients, 135 underwent 172 repeat surgical interventions (12.9% reoperation rate), with 29 (21.5%) of the 135 undergoing 2 or more separate procedures. The most common reasons for reoperation were infection, symptomatic implant, and pseudarthrosis. The authors concluded that repeat surgeries were relatively common after the initial surgical procedures. Having a clearer understanding of instrumentation-related complaints and reoperations may lead to improvement in this surgeon-controlled variable.

There are limitations to this study. The data regarding clinical courses were collected by retrospective chart review, which has known limitations. To offset this, we collected prospective outcome data with use of the SF-12, the SRS-22R, and a spine-related complaints questionnaire. No control group was available for comparison of outcomes in our cohort. We used the SF-12 and previously published normative values for the SRS-22R for comparison with population norms. Such comparisons have inherent limitations, as the groups vary by sex and mean age; our cohort was primarily female and more than a decade older than the controls.

Only 35% of the patients who met the inclusion criteria had complete data that could be included in our analysis. Although there was no statistically significant difference in demographics between patients with and without follow-up data available, this low response rate could have introduced selection bias. Ideally, patients should have been seen in clinic, standing radiographs should have been taken, and pulmonary function tests should have been performed. However, these patients were asymptomatic, and ethical and insurance issues prevented those actions. Thus, any radiographic changes occurring over the intervening years, from the last clinic visit to completion of the surveys, were not documented. This situation may or may not have limited our findings, as other authors have found low correlation between radiographic outcomes and clinical outcome measures.^13,14,19,36 During the period when these surgeries were performed, segmental spine instrumentation with hooks was the standard of care for deformity correction in AIS; therefore, all posterior instrumentations were done with hook-only segmental fixation. Current pedicle screw–based techniques that allow for additional correction of the deformity may provide different outcomes in the future.

We think that, despite the inherent limitations of this study, our data will be useful in the treatment of AIS. Our results suggest that postoperative spinal complaints are common and that, compared with an unaffected adolescent population, patients with AIS score significantly lower on pain and appearance domains of outcomes testing at a mean of 12.7 years after index fusion. Nevertheless, the outcomes do not seem to be of sufficient severity to affect general health and QOL as measured by outcomes testing.

Spinal deformity correction is performed to prevent impaired pulmonary function and spine-related disability later in life.^42,43 Thus, longer-term studies, involving patients in their fifth and sixth decades of life, are needed to determine whether patients with AIS will have QOL outcomes, pulmonary function, and spine-related problems similar to those in the general population. In this cohort of young adults, smoking status was the only predictor of HR-QOL measures, and spinal deformity correction did not lead to decreased HR-QOL.

The goal of surgical treatment of adolescent idiopathic scoliosis (AIS) is to prevent disability associated with curve progression.¹ Early studies tended to focus on radiographic measures, such as curve correction and sagittal balance, rather than on improvements in quality of life (QOL).^2-5 Although studies have reported on QOL in patients treated surgically for scoliosis,^6-11 these studies were largely limited by small sample size and inclusion of patients with congenital and neuromuscular scoliosis,⁹ lack of a generic measure of QOL,^6,7 or lack of surgical treatment of patients in the cohort.¹⁰

We conducted a study to determine disease-specific and general health-related QOL (HR-QOL) in young adults who underwent surgical correction of their spinal deformity during adolescence and to evaluate associated complications and reoperations.

Materials and Methods

After obtaining institutional review board approval, we queried the surgical database of a large metropolitan tertiary referral center for consecutive patients who had undergone spine deformity correction between the ages of 10 and 17 years (January 1993–December 2003). Hospital and medical records were retrospectively reviewed to confirm the diagnosis of AIS. Patients with congenital, neuromuscular, juvenile, or infantile scoliosis were excluded. Patients with intraspinal pathology (eg, tethered cord, syringomyelia), developmental delay, chromosomal abnormality, or congenital heart disease were also excluded. Patients were contacted by mail or telephone, and the Scoliosis Research Society–22R (SRS-22R)^12-15 and the Short Form–12 (SF-12)¹⁶ were administered. Standard demographic and surgical data were also collected.

The SRS-22R is a scoliosis-specific HR-QOL questionnaire with 22 items, 5 domains (pain, activity, appearance, mental, satisfaction), and a total score.^12-15 Each domain score ranges from 1 to 5 (higher scores indicating better outcomes). The SRS-22R is the outcome instrument most widely used to measure HR-QOL changes in patients with scoliosis, and it is available in several languages.^17-26

The SF-12, a 12-item self-administered short-form health status survey developed in the Medical Outcomes Study, measures patient-based health status. Two composite scores can be calculated: physical composite summary (PCS) and mental composite summary (MCS).¹⁶ Using norm-based scoring, all domain scales have a mean (SD) of 50 (10) based on the general 1998 US population. Thus, scores under 50 fall below the general population mean.

In addition, patients were surveyed to determine the incidence of spine-related symptoms and complaints, including activity limitations, rib prominence, waistline asymmetry, back pain, limited range of motion (ROM), shortness of breath, wound/scar problems, lung disease/asthma, heart disease, high blood pressure, and arthritis. Data regarding postoperative treatment regimens of physical therapy, narcotic pain medication, spinal/epidural injections, and nonsteroidal anti-inflammatory drug (NSAID) use were collected. Patients were also queried regarding their current working status and smoking status.

Standard demographic and surgical data were collected from hospital and office charts and radiographs. Data collected included history of bracing, age at index surgery, number of levels fused, surgical approach (anterior, posterior, combined), postoperative complications (eg, ileus, wound infection, anemia, pneumonia), and immediate preoperative and final postoperative radiographic measures. Data on need for subsequent revision surgery and indications for revision surgery were also collected.

Preoperative and latest follow-up radiographs were measured to determine curve magnitude, sagittal and coronal balance, and percentage curve correction. Coronal balance was defined as the distance between a plumb line drawn vertically from the spinous process of C7 and the central sacral line on full-length posteroanterior radiographs. Sagittal balance was defined as the distance of a plumb line drawn vertically from the center of the body of C7 and the posterosuperior endplate of S1.²⁷

Regression analysis was performed to identify factors predictive of SRS-22R total scores. Factors included in the analysis were sex, age at surgery, Lenke type, surgery type (anterior, posterior, anteroposterior), number of levels fused, lowest instrumented vertebra, perioperative complications, percentage curve correction, postoperative coronal and sagittal balance, smoking status, and need for revision surgery. Although age and sex were considered variables outside the surgeon’s control, they were included in the model, as previous studies have shown that SRS scores varied by age and sex both in adolescents²⁸ and adults.²⁹ Significance was set at P < .01. All data analysis was performed with IBM SPSS Version 19.0 (Somers, New York).

Results

Of the 384 postoperative patients identified for study inclusion, 134 (35%) completed surveys. Sixteen patients with nonidiopathic scoliosis were excluded, leaving 118 available for analysis. Of the remaining patients, 248 (64%) could not be contacted because of a change in address or phone number. Two patients (1%) were unwilling to complete survey requests. There was no statistically significant difference in demographics between patients with and without follow-up data available. Demographics are summarized in Table 1. There were 109 females (92%). Mean (SD) age at surgery was 14.1 (1.9) years. Only 37 (31%) were braced before surgery. Table 2 summarizes the radiographic data. Mean (SD) major Cobb angle was 49.7° (7.8°). Eighty-five patients (72%) underwent posterior fusion with instrumentation using hooks only; another 16 (14%) had anterior-only surgery, and another 17 (14%) had combined anterior-posterior surgery. A mean of 7.8 levels were fused. Index surgery data and lowest instrumented vertebra distribution are summarized in Table 3. Mean (SD) percentage curve correction was 48.9% (8.4%).

Seven patients had a total of 8 perioperative complications: anemia requiring transfusion (2), ileus necessitating nasogastric tube insertion (2), superficial wound infection treated with oral antibiotics and local wound care (2), wound drainage and erythema (1), and pneumonia (1). Mean (SD) length of clinical and radiographic follow-up was 57.9 (36.3) months.

Table 4 summarizes the long-term complications. Of the 38 patients with long-term complications, 14 required reoperation. The indications were disc herniation (2 patients), painful instrumentation (7), crankshaft phenomenon (1), nonunion (1), and adjacent-level degeneration (3). Both disc herniations were at L5–S1, several segments below the distal extent of the fusion. Of the 7 patients who had painful instrumentation removed, 6 had the entire construct removed, and 1 had the proximal half of a rod taken out. The 3 patients with adjacent-level degeneration had stenosis at the distal end of the construct—at L5–S1 (2 patients) or L2–L3 (1 patient).

Mean (SD) time between surgery and completion of the surveys/questionnaires was 12.7 (3.2) years (range, 10-18 years). Mean age of respondents was 26.8 years. Twenty-five respondents (21%) were smokers. Mean (SD) outcome scores were 50.9 (9.4) for SF-12 PCS and 49.4 (10.2) for SF-12 MCS. Eighteen patients (15%) had SF-12 PCS scores 1 SD below normal, and 15 (13%) had SF-12 MCS scores 1 SD below normal. Mean (SD) SRS-22R Total score was 4.0 (0.7). Means, standard deviations, and distribution of SRS domain scores are summarized in Table 5. Of the variables, only current smoking (P < .001) was predictive of SRS-22R Total scores, accounting for 20% of their variability (Table 6).

One hundred patients (85%) had jobs, mostly desk jobs. The postoperative limitations most commonly reported are summarized in Table 7. These included at least intermittent back pain in 90 patients (76%), limited ROM in 52 (44%), and activity limitations in 54 (46%). Less common limitations were waistline imbalance in 41 (35%), rib prominence in 28 (24%), wound/scar problems in 18 (15%), and shortness of breath in 18 (15%). Other related medical problems were lung disease/asthma in 11 (9%), osteoarthritis/degenerative arthritis in 11 (9%), heart disease in 3 (3%), and high blood pressure in 2 (2%).

A minority of patients also participated in postoperative treatment regimens. The most common treatment was regular use of NSAIDs (25 patients, 21%). Other treatments were physical therapy (14, 12%), narcotic pain medication use (5, 4%), and epidural steroid injections (5, 4%). Table 8 summarizes the postoperative treatments used by patients with scoliosis.

Discussion

A major concern about prophylactic interventions for diseases is that the treatment will harm the patient. This is especially true for major spine surgery performed on adolescents with minimal symptoms. Although the incidence of perioperative complications in children undergoing corrective spinal surgery for AIS has been reported,^30-32 the effect of the surgery on the disease-specific HR-QOL outcomes of these individuals as young adults has not been previously studied. Over the past few decades, a paradigm shift in understanding health and disability has occurred, with increased emphasis being placed on HR-QOL outcomes measures and understanding disability as relating to a measureable impact of the functioning of an individual after a change in health or environment. This change was substantiated when the World Health Organization endorsed the International Classification of Functioning, Disability and Health.³³ In light of this shift, we present the disease-specific and general HR-QOL outcomes of young adults who had undergone surgical correction for spinal deformity during adolescence, as well as their associated complications and reoperations, in an attempt to identify targets for improvement.

Our patient-reported outcomes demonstrated a high incidence of occasional back pain, activity-related complaints, and limited ROM. Comparison of our cohort’s SRS-22R outcomes with previously published normative values for the unaffected adolescent population^28,34 suggests worse scores for the disease-specific SRS-22R domains of pain and appearance. In 2012, Daubs and colleagues³⁴ reported that normative scores on various SRS-22 domains were statistically lower with age (scores decreased from age 10 to age 19 years). Both Verma and colleagues²⁸ and Daubs and colleagues³⁴ reported lower scores for females than for males. Therefore, it is unclear whether the differences observed in our cohort may be accounted for by the larger proportion of females compared with the normative data.

General health scores on the SF-12 were similar to the population norm (mean [SD]) of 50 (10) referenced by Ware and colleagues.¹⁶ These findings suggest that, though pain and appearance may be statistically lower in our cohort—as measured with the SRS-22R—the cohort’s spine-related symptoms do not seem to lower its general health. Eighty-five percent of the patients were working at the time of the survey, further supporting a relatively normal level of overall function. In a retrospective review by Takayama and colleagues,⁹ similar results were found with regard to working after AIS fusion surgery. Of 32 patients treated surgically for scoliosis, at a mean of 21.1 years after the index fusion 27 (84.4%) were or had been engaged in various occupations without marked difficulty.

Our results in a cohort of patients with segmental instrumentation using hooks are similar to results in other studies of long-term HR-QOL measures in patients with AIS and Harrington rod instrumentation. Danielsson and Nachemson³⁵ evaluated patients with surgically treated AIS with at least 20-year follow-up and reported that, in their surgical cohort with a mean age of 39.7 years, mean SF-36 PCS score was 50.9, and mean SF-36 MCS score was 50.2. In a recent study of patients with AIS and Harrington rod instrumentation, those of a mean age of 32.3 years had a mean score of 50.9 for both SF-36 PCS and SF-36 MCS.³⁶

Regression analysis identified only smoking as a predictor of SRS-22R Total scores. This finding, that smokers have a lower health state, is expected even in the general population.³⁷ Interestingly, bracing before surgery, Lenke type, surgery type, number of levels fused, lowest instrumented vertebra, incidence of perioperative complications, percentage curve correction, postoperative sagittal and coronal balance, and need for revision surgery did not influence HR-QOL measures in this cohort.

Our cohort’s incidence of occasional back pain was 76% (90/118 patients). Other reports have had similar findings. In 2012, Bas and colleagues³⁸ studied self-reported pain in 126 consecutive patients with scoliosis and instrumented fusion. In their cohort, “most participants reported ‘no pain’ (38.5%) or ‘mild pain’ (30.8%) and 72.1% of participants reported a current work/school activity level of 100% normal.” Also in 2012, Rushton and Grevitt³⁹ reported on a review and statistical analysis of the literature on HR-QOL in adolescents with untreated AIS and in unaffected adolescents. Their goal was to identify whether there were any differences in HR-QOL and, if so, whether they were clinically relevant. The authors concluded that pain and self-image tended to be statistically lower among cohorts with AIS but that only self-image was consistently different clinically between untreated patients with AIS and their unaffected peers.

Cosmetic complaints, though less common than functional concerns, affected a substantial percentage of our cohort. Waistline imbalance complaints were more common than rib prominence or scar-related complaints. The validity of patient-reported waistline imbalance is not known but may contribute to the SRS-22R outcomes in this cohort, particularly with regard to appearance scores. Respiratory symptoms, particularly those related to shortness of breath, were reported by 15% of patients. Respiratory symptoms may be in part secondary to underlying lung disease; smoking was reported by 21% of patients and asthma by 9%.

Few additional postoperative treatments were reported by patients. The most common treatment was regular use of NSAIDs (21%), followed by postoperative physical therapy (12%). Opiate medication use and spinal injections were rare—consistent with results reported by Danielsson and Nachemson³⁵ in 2003.

Implant-related complaints, including painful instrumentation (13%) and implant prominence (9%), were some of the most common complaints in our study group. Although not all symptomatic instrumentation required surgical revision, 7 (50%) of the 14 additional spine surgeries were related to painful and/or prominent posterior instrumentation. Additional spine surgery was reported in 11.9% of our patients. Other indications for reoperation were disc herniation, crankshaft phenomenon, nonunion, and adjacent-level degeneration. Our rate of revision surgery is supported by the literature. In 2009, Luhmann and colleagues⁴⁰ reported that 41 (3.9%) of 1057 primary spine fusions for idiopathic scoliosis required reoperation; the indications included infection (16/1057, 1.5%), pseudarthrosis (12, 1.1%), and painful/prominent implant (7, 0.7%). Richards and colleagues⁴¹ similarly reported on 1046 patients who underwent fusion for AIS. Of these patients, 135 underwent 172 repeat surgical interventions (12.9% reoperation rate), with 29 (21.5%) of the 135 undergoing 2 or more separate procedures. The most common reasons for reoperation were infection, symptomatic implant, and pseudarthrosis. The authors concluded that repeat surgeries were relatively common after the initial surgical procedures. Having a clearer understanding of instrumentation-related complaints and reoperations may lead to improvement in this surgeon-controlled variable.

There are limitations to this study. The data regarding clinical courses were collected by retrospective chart review, which has known limitations. To offset this, we collected prospective outcome data with use of the SF-12, the SRS-22R, and a spine-related complaints questionnaire. No control group was available for comparison of outcomes in our cohort. We used the SF-12 and previously published normative values for the SRS-22R for comparison with population norms. Such comparisons have inherent limitations, as the groups vary by sex and mean age; our cohort was primarily female and more than a decade older than the controls.

Only 35% of the patients who met the inclusion criteria had complete data that could be included in our analysis. Although there was no statistically significant difference in demographics between patients with and without follow-up data available, this low response rate could have introduced selection bias. Ideally, patients should have been seen in clinic, standing radiographs should have been taken, and pulmonary function tests should have been performed. However, these patients were asymptomatic, and ethical and insurance issues prevented those actions. Thus, any radiographic changes occurring over the intervening years, from the last clinic visit to completion of the surveys, were not documented. This situation may or may not have limited our findings, as other authors have found low correlation between radiographic outcomes and clinical outcome measures.^13,14,19,36 During the period when these surgeries were performed, segmental spine instrumentation with hooks was the standard of care for deformity correction in AIS; therefore, all posterior instrumentations were done with hook-only segmental fixation. Current pedicle screw–based techniques that allow for additional correction of the deformity may provide different outcomes in the future.

We think that, despite the inherent limitations of this study, our data will be useful in the treatment of AIS. Our results suggest that postoperative spinal complaints are common and that, compared with an unaffected adolescent population, patients with AIS score significantly lower on pain and appearance domains of outcomes testing at a mean of 12.7 years after index fusion. Nevertheless, the outcomes do not seem to be of sufficient severity to affect general health and QOL as measured by outcomes testing.

Spinal deformity correction is performed to prevent impaired pulmonary function and spine-related disability later in life.^42,43 Thus, longer-term studies, involving patients in their fifth and sixth decades of life, are needed to determine whether patients with AIS will have QOL outcomes, pulmonary function, and spine-related problems similar to those in the general population. In this cohort of young adults, smoking status was the only predictor of HR-QOL measures, and spinal deformity correction did not lead to decreased HR-QOL.

The goal of surgical treatment of adolescent idiopathic scoliosis (AIS) is to prevent disability associated with curve progression.¹ Early studies tended to focus on radiographic measures, such as curve correction and sagittal balance, rather than on improvements in quality of life (QOL).^2-5 Although studies have reported on QOL in patients treated surgically for scoliosis,^6-11 these studies were largely limited by small sample size and inclusion of patients with congenital and neuromuscular scoliosis,⁹ lack of a generic measure of QOL,^6,7 or lack of surgical treatment of patients in the cohort.¹⁰

We conducted a study to determine disease-specific and general health-related QOL (HR-QOL) in young adults who underwent surgical correction of their spinal deformity during adolescence and to evaluate associated complications and reoperations.

Materials and Methods

After obtaining institutional review board approval, we queried the surgical database of a large metropolitan tertiary referral center for consecutive patients who had undergone spine deformity correction between the ages of 10 and 17 years (January 1993–December 2003). Hospital and medical records were retrospectively reviewed to confirm the diagnosis of AIS. Patients with congenital, neuromuscular, juvenile, or infantile scoliosis were excluded. Patients with intraspinal pathology (eg, tethered cord, syringomyelia), developmental delay, chromosomal abnormality, or congenital heart disease were also excluded. Patients were contacted by mail or telephone, and the Scoliosis Research Society–22R (SRS-22R)^12-15 and the Short Form–12 (SF-12)¹⁶ were administered. Standard demographic and surgical data were also collected.

The SRS-22R is a scoliosis-specific HR-QOL questionnaire with 22 items, 5 domains (pain, activity, appearance, mental, satisfaction), and a total score.^12-15 Each domain score ranges from 1 to 5 (higher scores indicating better outcomes). The SRS-22R is the outcome instrument most widely used to measure HR-QOL changes in patients with scoliosis, and it is available in several languages.^17-26

The SF-12, a 12-item self-administered short-form health status survey developed in the Medical Outcomes Study, measures patient-based health status. Two composite scores can be calculated: physical composite summary (PCS) and mental composite summary (MCS).¹⁶ Using norm-based scoring, all domain scales have a mean (SD) of 50 (10) based on the general 1998 US population. Thus, scores under 50 fall below the general population mean.

In addition, patients were surveyed to determine the incidence of spine-related symptoms and complaints, including activity limitations, rib prominence, waistline asymmetry, back pain, limited range of motion (ROM), shortness of breath, wound/scar problems, lung disease/asthma, heart disease, high blood pressure, and arthritis. Data regarding postoperative treatment regimens of physical therapy, narcotic pain medication, spinal/epidural injections, and nonsteroidal anti-inflammatory drug (NSAID) use were collected. Patients were also queried regarding their current working status and smoking status.

Standard demographic and surgical data were collected from hospital and office charts and radiographs. Data collected included history of bracing, age at index surgery, number of levels fused, surgical approach (anterior, posterior, combined), postoperative complications (eg, ileus, wound infection, anemia, pneumonia), and immediate preoperative and final postoperative radiographic measures. Data on need for subsequent revision surgery and indications for revision surgery were also collected.

Preoperative and latest follow-up radiographs were measured to determine curve magnitude, sagittal and coronal balance, and percentage curve correction. Coronal balance was defined as the distance between a plumb line drawn vertically from the spinous process of C7 and the central sacral line on full-length posteroanterior radiographs. Sagittal balance was defined as the distance of a plumb line drawn vertically from the center of the body of C7 and the posterosuperior endplate of S1.²⁷

Regression analysis was performed to identify factors predictive of SRS-22R total scores. Factors included in the analysis were sex, age at surgery, Lenke type, surgery type (anterior, posterior, anteroposterior), number of levels fused, lowest instrumented vertebra, perioperative complications, percentage curve correction, postoperative coronal and sagittal balance, smoking status, and need for revision surgery. Although age and sex were considered variables outside the surgeon’s control, they were included in the model, as previous studies have shown that SRS scores varied by age and sex both in adolescents²⁸ and adults.²⁹ Significance was set at P < .01. All data analysis was performed with IBM SPSS Version 19.0 (Somers, New York).

Results

Of the 384 postoperative patients identified for study inclusion, 134 (35%) completed surveys. Sixteen patients with nonidiopathic scoliosis were excluded, leaving 118 available for analysis. Of the remaining patients, 248 (64%) could not be contacted because of a change in address or phone number. Two patients (1%) were unwilling to complete survey requests. There was no statistically significant difference in demographics between patients with and without follow-up data available. Demographics are summarized in Table 1. There were 109 females (92%). Mean (SD) age at surgery was 14.1 (1.9) years. Only 37 (31%) were braced before surgery. Table 2 summarizes the radiographic data. Mean (SD) major Cobb angle was 49.7° (7.8°). Eighty-five patients (72%) underwent posterior fusion with instrumentation using hooks only; another 16 (14%) had anterior-only surgery, and another 17 (14%) had combined anterior-posterior surgery. A mean of 7.8 levels were fused. Index surgery data and lowest instrumented vertebra distribution are summarized in Table 3. Mean (SD) percentage curve correction was 48.9% (8.4%).

Seven patients had a total of 8 perioperative complications: anemia requiring transfusion (2), ileus necessitating nasogastric tube insertion (2), superficial wound infection treated with oral antibiotics and local wound care (2), wound drainage and erythema (1), and pneumonia (1). Mean (SD) length of clinical and radiographic follow-up was 57.9 (36.3) months.

Table 4 summarizes the long-term complications. Of the 38 patients with long-term complications, 14 required reoperation. The indications were disc herniation (2 patients), painful instrumentation (7), crankshaft phenomenon (1), nonunion (1), and adjacent-level degeneration (3). Both disc herniations were at L5–S1, several segments below the distal extent of the fusion. Of the 7 patients who had painful instrumentation removed, 6 had the entire construct removed, and 1 had the proximal half of a rod taken out. The 3 patients with adjacent-level degeneration had stenosis at the distal end of the construct—at L5–S1 (2 patients) or L2–L3 (1 patient).

Mean (SD) time between surgery and completion of the surveys/questionnaires was 12.7 (3.2) years (range, 10-18 years). Mean age of respondents was 26.8 years. Twenty-five respondents (21%) were smokers. Mean (SD) outcome scores were 50.9 (9.4) for SF-12 PCS and 49.4 (10.2) for SF-12 MCS. Eighteen patients (15%) had SF-12 PCS scores 1 SD below normal, and 15 (13%) had SF-12 MCS scores 1 SD below normal. Mean (SD) SRS-22R Total score was 4.0 (0.7). Means, standard deviations, and distribution of SRS domain scores are summarized in Table 5. Of the variables, only current smoking (P < .001) was predictive of SRS-22R Total scores, accounting for 20% of their variability (Table 6).

One hundred patients (85%) had jobs, mostly desk jobs. The postoperative limitations most commonly reported are summarized in Table 7. These included at least intermittent back pain in 90 patients (76%), limited ROM in 52 (44%), and activity limitations in 54 (46%). Less common limitations were waistline imbalance in 41 (35%), rib prominence in 28 (24%), wound/scar problems in 18 (15%), and shortness of breath in 18 (15%). Other related medical problems were lung disease/asthma in 11 (9%), osteoarthritis/degenerative arthritis in 11 (9%), heart disease in 3 (3%), and high blood pressure in 2 (2%).

A minority of patients also participated in postoperative treatment regimens. The most common treatment was regular use of NSAIDs (25 patients, 21%). Other treatments were physical therapy (14, 12%), narcotic pain medication use (5, 4%), and epidural steroid injections (5, 4%). Table 8 summarizes the postoperative treatments used by patients with scoliosis.

Discussion

A major concern about prophylactic interventions for diseases is that the treatment will harm the patient. This is especially true for major spine surgery performed on adolescents with minimal symptoms. Although the incidence of perioperative complications in children undergoing corrective spinal surgery for AIS has been reported,^30-32 the effect of the surgery on the disease-specific HR-QOL outcomes of these individuals as young adults has not been previously studied. Over the past few decades, a paradigm shift in understanding health and disability has occurred, with increased emphasis being placed on HR-QOL outcomes measures and understanding disability as relating to a measureable impact of the functioning of an individual after a change in health or environment. This change was substantiated when the World Health Organization endorsed the International Classification of Functioning, Disability and Health.³³ In light of this shift, we present the disease-specific and general HR-QOL outcomes of young adults who had undergone surgical correction for spinal deformity during adolescence, as well as their associated complications and reoperations, in an attempt to identify targets for improvement.

Our patient-reported outcomes demonstrated a high incidence of occasional back pain, activity-related complaints, and limited ROM. Comparison of our cohort’s SRS-22R outcomes with previously published normative values for the unaffected adolescent population^28,34 suggests worse scores for the disease-specific SRS-22R domains of pain and appearance. In 2012, Daubs and colleagues³⁴ reported that normative scores on various SRS-22 domains were statistically lower with age (scores decreased from age 10 to age 19 years). Both Verma and colleagues²⁸ and Daubs and colleagues³⁴ reported lower scores for females than for males. Therefore, it is unclear whether the differences observed in our cohort may be accounted for by the larger proportion of females compared with the normative data.

General health scores on the SF-12 were similar to the population norm (mean [SD]) of 50 (10) referenced by Ware and colleagues.¹⁶ These findings suggest that, though pain and appearance may be statistically lower in our cohort—as measured with the SRS-22R—the cohort’s spine-related symptoms do not seem to lower its general health. Eighty-five percent of the patients were working at the time of the survey, further supporting a relatively normal level of overall function. In a retrospective review by Takayama and colleagues,⁹ similar results were found with regard to working after AIS fusion surgery. Of 32 patients treated surgically for scoliosis, at a mean of 21.1 years after the index fusion 27 (84.4%) were or had been engaged in various occupations without marked difficulty.

Our results in a cohort of patients with segmental instrumentation using hooks are similar to results in other studies of long-term HR-QOL measures in patients with AIS and Harrington rod instrumentation. Danielsson and Nachemson³⁵ evaluated patients with surgically treated AIS with at least 20-year follow-up and reported that, in their surgical cohort with a mean age of 39.7 years, mean SF-36 PCS score was 50.9, and mean SF-36 MCS score was 50.2. In a recent study of patients with AIS and Harrington rod instrumentation, those of a mean age of 32.3 years had a mean score of 50.9 for both SF-36 PCS and SF-36 MCS.³⁶

Regression analysis identified only smoking as a predictor of SRS-22R Total scores. This finding, that smokers have a lower health state, is expected even in the general population.³⁷ Interestingly, bracing before surgery, Lenke type, surgery type, number of levels fused, lowest instrumented vertebra, incidence of perioperative complications, percentage curve correction, postoperative sagittal and coronal balance, and need for revision surgery did not influence HR-QOL measures in this cohort.

Our cohort’s incidence of occasional back pain was 76% (90/118 patients). Other reports have had similar findings. In 2012, Bas and colleagues³⁸ studied self-reported pain in 126 consecutive patients with scoliosis and instrumented fusion. In their cohort, “most participants reported ‘no pain’ (38.5%) or ‘mild pain’ (30.8%) and 72.1% of participants reported a current work/school activity level of 100% normal.” Also in 2012, Rushton and Grevitt³⁹ reported on a review and statistical analysis of the literature on HR-QOL in adolescents with untreated AIS and in unaffected adolescents. Their goal was to identify whether there were any differences in HR-QOL and, if so, whether they were clinically relevant. The authors concluded that pain and self-image tended to be statistically lower among cohorts with AIS but that only self-image was consistently different clinically between untreated patients with AIS and their unaffected peers.

Cosmetic complaints, though less common than functional concerns, affected a substantial percentage of our cohort. Waistline imbalance complaints were more common than rib prominence or scar-related complaints. The validity of patient-reported waistline imbalance is not known but may contribute to the SRS-22R outcomes in this cohort, particularly with regard to appearance scores. Respiratory symptoms, particularly those related to shortness of breath, were reported by 15% of patients. Respiratory symptoms may be in part secondary to underlying lung disease; smoking was reported by 21% of patients and asthma by 9%.

Few additional postoperative treatments were reported by patients. The most common treatment was regular use of NSAIDs (21%), followed by postoperative physical therapy (12%). Opiate medication use and spinal injections were rare—consistent with results reported by Danielsson and Nachemson³⁵ in 2003.

Implant-related complaints, including painful instrumentation (13%) and implant prominence (9%), were some of the most common complaints in our study group. Although not all symptomatic instrumentation required surgical revision, 7 (50%) of the 14 additional spine surgeries were related to painful and/or prominent posterior instrumentation. Additional spine surgery was reported in 11.9% of our patients. Other indications for reoperation were disc herniation, crankshaft phenomenon, nonunion, and adjacent-level degeneration. Our rate of revision surgery is supported by the literature. In 2009, Luhmann and colleagues⁴⁰ reported that 41 (3.9%) of 1057 primary spine fusions for idiopathic scoliosis required reoperation; the indications included infection (16/1057, 1.5%), pseudarthrosis (12, 1.1%), and painful/prominent implant (7, 0.7%). Richards and colleagues⁴¹ similarly reported on 1046 patients who underwent fusion for AIS. Of these patients, 135 underwent 172 repeat surgical interventions (12.9% reoperation rate), with 29 (21.5%) of the 135 undergoing 2 or more separate procedures. The most common reasons for reoperation were infection, symptomatic implant, and pseudarthrosis. The authors concluded that repeat surgeries were relatively common after the initial surgical procedures. Having a clearer understanding of instrumentation-related complaints and reoperations may lead to improvement in this surgeon-controlled variable.

There are limitations to this study. The data regarding clinical courses were collected by retrospective chart review, which has known limitations. To offset this, we collected prospective outcome data with use of the SF-12, the SRS-22R, and a spine-related complaints questionnaire. No control group was available for comparison of outcomes in our cohort. We used the SF-12 and previously published normative values for the SRS-22R for comparison with population norms. Such comparisons have inherent limitations, as the groups vary by sex and mean age; our cohort was primarily female and more than a decade older than the controls.

Only 35% of the patients who met the inclusion criteria had complete data that could be included in our analysis. Although there was no statistically significant difference in demographics between patients with and without follow-up data available, this low response rate could have introduced selection bias. Ideally, patients should have been seen in clinic, standing radiographs should have been taken, and pulmonary function tests should have been performed. However, these patients were asymptomatic, and ethical and insurance issues prevented those actions. Thus, any radiographic changes occurring over the intervening years, from the last clinic visit to completion of the surveys, were not documented. This situation may or may not have limited our findings, as other authors have found low correlation between radiographic outcomes and clinical outcome measures.^13,14,19,36 During the period when these surgeries were performed, segmental spine instrumentation with hooks was the standard of care for deformity correction in AIS; therefore, all posterior instrumentations were done with hook-only segmental fixation. Current pedicle screw–based techniques that allow for additional correction of the deformity may provide different outcomes in the future.

We think that, despite the inherent limitations of this study, our data will be useful in the treatment of AIS. Our results suggest that postoperative spinal complaints are common and that, compared with an unaffected adolescent population, patients with AIS score significantly lower on pain and appearance domains of outcomes testing at a mean of 12.7 years after index fusion. Nevertheless, the outcomes do not seem to be of sufficient severity to affect general health and QOL as measured by outcomes testing.

Spinal deformity correction is performed to prevent impaired pulmonary function and spine-related disability later in life.^42,43 Thus, longer-term studies, involving patients in their fifth and sixth decades of life, are needed to determine whether patients with AIS will have QOL outcomes, pulmonary function, and spine-related problems similar to those in the general population. In this cohort of young adults, smoking status was the only predictor of HR-QOL measures, and spinal deformity correction did not lead to decreased HR-QOL.

Chordomas persist as one of the rarer malignancies, accounting for approximately 1% to 4% of primary bone cancers.¹ When chordomas occur, these tumors localize predominantly in the sacrococcygeal region.² In addition to the urgency for addressing a relatively fast-growing tumor, the anatomical complexity of this area complicates the potential treatments. Furthermore, because of the lack of definitive symptoms, diagnosis is often difficult and typically occurs later in the disease progression.³ An aggressive treatment approach is often warranted because of the biologically aggressive nature of this disease. Full or partial sacrectomy is often the only option that offers the possibility of a long-term cure.⁴ A sacrectomy is a destructive procedure that can lead to mechanical instability depending on the extent of the surgical resection. When the entire sacrum is removed, there is an obvious need for lumbar-pelvic fixation; however, traditionally, partial sacrectomy procedures have been successfully performed without the need for instrumentation.^3,4

This report describes the case of a patient with a noninstrumented sacrectomy procedure distal to the S2 foramen that resulted in an insufficiency fracture. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 66-year-old woman presented with severe lower back pain of a month’s duration. Her pain was localized to the coccyx area and did not radiate to the lower legs. Although the pain could not be elicited by palpation, pain occurred when sitting and increased when standing for prolonged periods. Three weeks prior to the patient’s initial office visit, she noticed transient constipation and urinary retention. She denied any fever, chills, nausea, vomiting, unexplained weight loss, weight gain, and abdominal pain. There were no motor deficits in the lower limbs. Sensation was intact in the lower limbs except for the posterior aspect of the left leg down to the popliteal fossa, where light touch perception was absent. She recalled the loss of sensation in this area 20 years earlier, and it had neither progressed nor abated since then. She had a history of osteoarthritis and had been diagnosed with degenerative disc disease 20 years ago.

A radiographic review of her lumbar spine showed significant spinal stenosis and degenerative disease of the lumbar spine on non–contrast-enhanced magnetic resonance imaging (MRI). The MRI also revealed a large, soft-tissue mass at the S3-S4 level, eroding most of the S3 vertebral body and extending into the S4 vertebral body. The MRI images used for this analysis were insufficient in providing a complete portrayal of the entire mass. Because of these uncertainties, contrast-enhanced and non–contrast-enhanced pelvic MRIs were taken. The MRI analyses identified a mass density replacing the lower sacrum and upper coccyx that was bright in intensity on T2 and dim on T1 sequences. Sagittal imaging measurements were 5.9×2.5 cm and 4.4 cm right-to-left on coronal imaging. The mass extended beyond the involved sacrococcygeal segments and dorsally beyond the normal cortical margin of the sacrum and coccyx (Figures 1A, 1B). Next, a computer tomographic–guided needle biopsy through a posterior paraspinal approach was obtained. The biopsy consisted of fragments of a malignant neoplasm consistent with physaliferous cells. The specimen was positive for pankeratin, keratin AE1/AE3, epithelial membrane antigen, and S100 protein. This supported a diagnosis of a sacral chordoma. An en bloc sacrectomy at S2; lumbar laminectomy at L5, S1, and S2; and thecal sac transection at the S3 nerve roots were planned.

Surgical Procedure

The patient was placed in the prone position after a colostomy and harvesting of a rectus flap in the supine position. A midline incision was made from the spinous process of L5 down through the tip of the coccyx, and soft tissues were elevated while maintaining hemostasis. The most distal part of the coccyx was transected, and using a combination of electrocautery and paraspinal elevators, rectal and peritoneal tissues were elevated off the ventral component of the coccyx until a hand could easily reach the bifurcation of the iliac vessels. Electrocautery transected paraspinal muscles at the S1 and S2 levels while the more cranial paraspinal musculature was elevated to allow for a laminectomy. The spinous processes were removed from L5 and the sacrum with a Leksell rongeur. A high-speed burr thinned the dorsal lamina components of L5, S1, and the leading edge of S2. The L5, S1, and S2 nerve roots were identified. The gluteal muscles were elevated and the sacral coccygeal ligaments were transected. After identifying the sciatic notches, the S2 nerves exiting the foramen were identified, followed out through the sciatic notch, and a wire was passed through this region. Three 2-0 silk ties were applied to the exposed portion of the S3 and S4 nerve roots, and the nerves were transected because they were integrally involved with the tumor. Using a series of high-speed burrs and osteotomes, lateral cuts were made through the sciatic notch. The sacrum was osteotomized at the S2 sacral foramen through the anterior component with an osteotome, while a hand protected the ventral structures. The remaining parts of the S3 and S4 dorsal nerve roots were transected. An incision through the peritoneum was made to access the rectus flap, and a plastic surgeon closed the wounds and secured the flap. 

Postoperative Course

The patient’s final pathology confirmed a chordoma with negative margins. Postoperatively, the rectus flap became ischemic and a wound infection developed. It was irrigated, débrided, and treated with vacuum-assisted closure (VAC), in addition to perioperative antibiotic administration. An abdominal computed tomography (CT) scan did not show any fistula, and her wound remained healthy, pink, and viable as her VAC was changed every 3 days. Because the patient’s nutritional status was compromised, she started nutritional supplements in addition to a regular diet. Physical therapy was prescribed and the patient began bladder training with self-catheterization after a failed voiding trial attempt. After 2 months of convalescence, the patient had mobilized well and had progressed to walking without an ambulatory aide.

At her third postoperative month, the patient noted new onset of extreme pain in the groin and left thigh regions. The patient was examined and appeared to have a stable neurological exam. She had reproducible pain with a FABER (Flexion, Abduction, External Rotation, and Extension) test. MRI showed increased signal on short tau inversion recovery (STIR) sequences and T2-weighted images that was consistent with a left sacral ala stress fracture with a vertically oriented fracture line (Figures 2A, 2B). The patient was asked to begin utilizing a walker for ambulatory assistance, but her weight-bearing status was not changed. Over the course of 3 months, the patient noted a resolution of her pain. All postoperative MRI images confirmed the patient to be disease-free; and in addition, all of her follow-up radiographs showed a stable pelvic ring (Figures 3A, 3B). At her 2-year follow-up, the patient remained disease- and pain-free.

Discussion

Full discussions of the mechanical considerations of a partial sacrectomy have been described previously^5-8; however, surgeons typically consider the need for lumbar-pelvic stabilization when the surgical resection requires a violation of the S1 body. Approximately two-thirds of sacral tumors occur at or below the level of the S2 body.⁸ These lesions of the caudal sacrum can sometimes be effectively resected with transverse partial sacrectomy. Great care is taken to resect only the portion of the sacrum necessary for local disease control, sparing as much of the sacroiliac joint and as many of the lumbosacral nerve roots as possible.

Under normal conditions, the sacroiliac articulation is stabilized by both its geometric interface and its extraordinarily strong ligaments. This spatial arrangement conveys stability primarily against caudal migration of the sacrum. The sacroiliac, sacrotuberous, sacrospinous, and lumbosacral ligaments, which are among the strongest ligaments in the body, primarily act to provide stability to the pelvic ring by preventing diastasis. The combination of these factors renders the spinopelvic segment especially stable. Previously, 2 biomechanical studies that specifically looked at extreme loading patterns to better understand the need for lumbar-pelvic instrumentation predicted a fracture pattern when there was an inability of the base of the sacral ala to resist shear.^8,9 This is precisely where our patient’s insufficiency fracture occurred.

To our knowledge, this is the first reported in vivo evidence of this fracture pattern. While this patient’s potential history of osteoporosis may have elevated or contributed to her risk for fracture, her preoperative bone densitometry, with T scores of -1.0 on the left and right femur necks and 0.8 on her L1-L4 anteroposterior spine, would argue against this risk factor. None of these values represent a truly osteoporotic patient. It would appear that our patient sustained the fracture pattern predicted by Hugate and colleagues.⁸

The edema seen on the MRI most likely represents a fracture; however, sacroiliitis and infection are also potential diagnoses. Because there was no tumor in this region on the preoperative scans, we thought that a residual tumor was unlikely. The signal changes seen on T2 MRI sequences represent edema. The use of a bone scan that detects healing bone may have been a useful additional study to confirm this fracture as opposed to sacroiliitis. A CT scan would have been a potentially useful study to provide detail of fracture displacement and the overall fracture pattern. Standing plain radiographs are best for viewing fracture displacement with weight-bearing.

Surgeons contemplating performing partial sacrectomies should bear in mind that, even with preservation of the S1 body, a potential for fracture exists as evidenced by our patient. In our opinion, this patient did not require instrumentation but a more gradual rehabilitation program.

Chordomas persist as one of the rarer malignancies, accounting for approximately 1% to 4% of primary bone cancers.¹ When chordomas occur, these tumors localize predominantly in the sacrococcygeal region.² In addition to the urgency for addressing a relatively fast-growing tumor, the anatomical complexity of this area complicates the potential treatments. Furthermore, because of the lack of definitive symptoms, diagnosis is often difficult and typically occurs later in the disease progression.³ An aggressive treatment approach is often warranted because of the biologically aggressive nature of this disease. Full or partial sacrectomy is often the only option that offers the possibility of a long-term cure.⁴ A sacrectomy is a destructive procedure that can lead to mechanical instability depending on the extent of the surgical resection. When the entire sacrum is removed, there is an obvious need for lumbar-pelvic fixation; however, traditionally, partial sacrectomy procedures have been successfully performed without the need for instrumentation.^3,4

This report describes the case of a patient with a noninstrumented sacrectomy procedure distal to the S2 foramen that resulted in an insufficiency fracture. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 66-year-old woman presented with severe lower back pain of a month’s duration. Her pain was localized to the coccyx area and did not radiate to the lower legs. Although the pain could not be elicited by palpation, pain occurred when sitting and increased when standing for prolonged periods. Three weeks prior to the patient’s initial office visit, she noticed transient constipation and urinary retention. She denied any fever, chills, nausea, vomiting, unexplained weight loss, weight gain, and abdominal pain. There were no motor deficits in the lower limbs. Sensation was intact in the lower limbs except for the posterior aspect of the left leg down to the popliteal fossa, where light touch perception was absent. She recalled the loss of sensation in this area 20 years earlier, and it had neither progressed nor abated since then. She had a history of osteoarthritis and had been diagnosed with degenerative disc disease 20 years ago.

A radiographic review of her lumbar spine showed significant spinal stenosis and degenerative disease of the lumbar spine on non–contrast-enhanced magnetic resonance imaging (MRI). The MRI also revealed a large, soft-tissue mass at the S3-S4 level, eroding most of the S3 vertebral body and extending into the S4 vertebral body. The MRI images used for this analysis were insufficient in providing a complete portrayal of the entire mass. Because of these uncertainties, contrast-enhanced and non–contrast-enhanced pelvic MRIs were taken. The MRI analyses identified a mass density replacing the lower sacrum and upper coccyx that was bright in intensity on T2 and dim on T1 sequences. Sagittal imaging measurements were 5.9×2.5 cm and 4.4 cm right-to-left on coronal imaging. The mass extended beyond the involved sacrococcygeal segments and dorsally beyond the normal cortical margin of the sacrum and coccyx (Figures 1A, 1B). Next, a computer tomographic–guided needle biopsy through a posterior paraspinal approach was obtained. The biopsy consisted of fragments of a malignant neoplasm consistent with physaliferous cells. The specimen was positive for pankeratin, keratin AE1/AE3, epithelial membrane antigen, and S100 protein. This supported a diagnosis of a sacral chordoma. An en bloc sacrectomy at S2; lumbar laminectomy at L5, S1, and S2; and thecal sac transection at the S3 nerve roots were planned.

Surgical Procedure

The patient was placed in the prone position after a colostomy and harvesting of a rectus flap in the supine position. A midline incision was made from the spinous process of L5 down through the tip of the coccyx, and soft tissues were elevated while maintaining hemostasis. The most distal part of the coccyx was transected, and using a combination of electrocautery and paraspinal elevators, rectal and peritoneal tissues were elevated off the ventral component of the coccyx until a hand could easily reach the bifurcation of the iliac vessels. Electrocautery transected paraspinal muscles at the S1 and S2 levels while the more cranial paraspinal musculature was elevated to allow for a laminectomy. The spinous processes were removed from L5 and the sacrum with a Leksell rongeur. A high-speed burr thinned the dorsal lamina components of L5, S1, and the leading edge of S2. The L5, S1, and S2 nerve roots were identified. The gluteal muscles were elevated and the sacral coccygeal ligaments were transected. After identifying the sciatic notches, the S2 nerves exiting the foramen were identified, followed out through the sciatic notch, and a wire was passed through this region. Three 2-0 silk ties were applied to the exposed portion of the S3 and S4 nerve roots, and the nerves were transected because they were integrally involved with the tumor. Using a series of high-speed burrs and osteotomes, lateral cuts were made through the sciatic notch. The sacrum was osteotomized at the S2 sacral foramen through the anterior component with an osteotome, while a hand protected the ventral structures. The remaining parts of the S3 and S4 dorsal nerve roots were transected. An incision through the peritoneum was made to access the rectus flap, and a plastic surgeon closed the wounds and secured the flap. 

Postoperative Course

The patient’s final pathology confirmed a chordoma with negative margins. Postoperatively, the rectus flap became ischemic and a wound infection developed. It was irrigated, débrided, and treated with vacuum-assisted closure (VAC), in addition to perioperative antibiotic administration. An abdominal computed tomography (CT) scan did not show any fistula, and her wound remained healthy, pink, and viable as her VAC was changed every 3 days. Because the patient’s nutritional status was compromised, she started nutritional supplements in addition to a regular diet. Physical therapy was prescribed and the patient began bladder training with self-catheterization after a failed voiding trial attempt. After 2 months of convalescence, the patient had mobilized well and had progressed to walking without an ambulatory aide.

At her third postoperative month, the patient noted new onset of extreme pain in the groin and left thigh regions. The patient was examined and appeared to have a stable neurological exam. She had reproducible pain with a FABER (Flexion, Abduction, External Rotation, and Extension) test. MRI showed increased signal on short tau inversion recovery (STIR) sequences and T2-weighted images that was consistent with a left sacral ala stress fracture with a vertically oriented fracture line (Figures 2A, 2B). The patient was asked to begin utilizing a walker for ambulatory assistance, but her weight-bearing status was not changed. Over the course of 3 months, the patient noted a resolution of her pain. All postoperative MRI images confirmed the patient to be disease-free; and in addition, all of her follow-up radiographs showed a stable pelvic ring (Figures 3A, 3B). At her 2-year follow-up, the patient remained disease- and pain-free.

Discussion

Full discussions of the mechanical considerations of a partial sacrectomy have been described previously^5-8; however, surgeons typically consider the need for lumbar-pelvic stabilization when the surgical resection requires a violation of the S1 body. Approximately two-thirds of sacral tumors occur at or below the level of the S2 body.⁸ These lesions of the caudal sacrum can sometimes be effectively resected with transverse partial sacrectomy. Great care is taken to resect only the portion of the sacrum necessary for local disease control, sparing as much of the sacroiliac joint and as many of the lumbosacral nerve roots as possible.

Under normal conditions, the sacroiliac articulation is stabilized by both its geometric interface and its extraordinarily strong ligaments. This spatial arrangement conveys stability primarily against caudal migration of the sacrum. The sacroiliac, sacrotuberous, sacrospinous, and lumbosacral ligaments, which are among the strongest ligaments in the body, primarily act to provide stability to the pelvic ring by preventing diastasis. The combination of these factors renders the spinopelvic segment especially stable. Previously, 2 biomechanical studies that specifically looked at extreme loading patterns to better understand the need for lumbar-pelvic instrumentation predicted a fracture pattern when there was an inability of the base of the sacral ala to resist shear.^8,9 This is precisely where our patient’s insufficiency fracture occurred.

To our knowledge, this is the first reported in vivo evidence of this fracture pattern. While this patient’s potential history of osteoporosis may have elevated or contributed to her risk for fracture, her preoperative bone densitometry, with T scores of -1.0 on the left and right femur necks and 0.8 on her L1-L4 anteroposterior spine, would argue against this risk factor. None of these values represent a truly osteoporotic patient. It would appear that our patient sustained the fracture pattern predicted by Hugate and colleagues.⁸

The edema seen on the MRI most likely represents a fracture; however, sacroiliitis and infection are also potential diagnoses. Because there was no tumor in this region on the preoperative scans, we thought that a residual tumor was unlikely. The signal changes seen on T2 MRI sequences represent edema. The use of a bone scan that detects healing bone may have been a useful additional study to confirm this fracture as opposed to sacroiliitis. A CT scan would have been a potentially useful study to provide detail of fracture displacement and the overall fracture pattern. Standing plain radiographs are best for viewing fracture displacement with weight-bearing.

Surgeons contemplating performing partial sacrectomies should bear in mind that, even with preservation of the S1 body, a potential for fracture exists as evidenced by our patient. In our opinion, this patient did not require instrumentation but a more gradual rehabilitation program.

Chordomas persist as one of the rarer malignancies, accounting for approximately 1% to 4% of primary bone cancers.¹ When chordomas occur, these tumors localize predominantly in the sacrococcygeal region.² In addition to the urgency for addressing a relatively fast-growing tumor, the anatomical complexity of this area complicates the potential treatments. Furthermore, because of the lack of definitive symptoms, diagnosis is often difficult and typically occurs later in the disease progression.³ An aggressive treatment approach is often warranted because of the biologically aggressive nature of this disease. Full or partial sacrectomy is often the only option that offers the possibility of a long-term cure.⁴ A sacrectomy is a destructive procedure that can lead to mechanical instability depending on the extent of the surgical resection. When the entire sacrum is removed, there is an obvious need for lumbar-pelvic fixation; however, traditionally, partial sacrectomy procedures have been successfully performed without the need for instrumentation.^3,4

This report describes the case of a patient with a noninstrumented sacrectomy procedure distal to the S2 foramen that resulted in an insufficiency fracture. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 66-year-old woman presented with severe lower back pain of a month’s duration. Her pain was localized to the coccyx area and did not radiate to the lower legs. Although the pain could not be elicited by palpation, pain occurred when sitting and increased when standing for prolonged periods. Three weeks prior to the patient’s initial office visit, she noticed transient constipation and urinary retention. She denied any fever, chills, nausea, vomiting, unexplained weight loss, weight gain, and abdominal pain. There were no motor deficits in the lower limbs. Sensation was intact in the lower limbs except for the posterior aspect of the left leg down to the popliteal fossa, where light touch perception was absent. She recalled the loss of sensation in this area 20 years earlier, and it had neither progressed nor abated since then. She had a history of osteoarthritis and had been diagnosed with degenerative disc disease 20 years ago.

A radiographic review of her lumbar spine showed significant spinal stenosis and degenerative disease of the lumbar spine on non–contrast-enhanced magnetic resonance imaging (MRI). The MRI also revealed a large, soft-tissue mass at the S3-S4 level, eroding most of the S3 vertebral body and extending into the S4 vertebral body. The MRI images used for this analysis were insufficient in providing a complete portrayal of the entire mass. Because of these uncertainties, contrast-enhanced and non–contrast-enhanced pelvic MRIs were taken. The MRI analyses identified a mass density replacing the lower sacrum and upper coccyx that was bright in intensity on T2 and dim on T1 sequences. Sagittal imaging measurements were 5.9×2.5 cm and 4.4 cm right-to-left on coronal imaging. The mass extended beyond the involved sacrococcygeal segments and dorsally beyond the normal cortical margin of the sacrum and coccyx (Figures 1A, 1B). Next, a computer tomographic–guided needle biopsy through a posterior paraspinal approach was obtained. The biopsy consisted of fragments of a malignant neoplasm consistent with physaliferous cells. The specimen was positive for pankeratin, keratin AE1/AE3, epithelial membrane antigen, and S100 protein. This supported a diagnosis of a sacral chordoma. An en bloc sacrectomy at S2; lumbar laminectomy at L5, S1, and S2; and thecal sac transection at the S3 nerve roots were planned.

Surgical Procedure

The patient was placed in the prone position after a colostomy and harvesting of a rectus flap in the supine position. A midline incision was made from the spinous process of L5 down through the tip of the coccyx, and soft tissues were elevated while maintaining hemostasis. The most distal part of the coccyx was transected, and using a combination of electrocautery and paraspinal elevators, rectal and peritoneal tissues were elevated off the ventral component of the coccyx until a hand could easily reach the bifurcation of the iliac vessels. Electrocautery transected paraspinal muscles at the S1 and S2 levels while the more cranial paraspinal musculature was elevated to allow for a laminectomy. The spinous processes were removed from L5 and the sacrum with a Leksell rongeur. A high-speed burr thinned the dorsal lamina components of L5, S1, and the leading edge of S2. The L5, S1, and S2 nerve roots were identified. The gluteal muscles were elevated and the sacral coccygeal ligaments were transected. After identifying the sciatic notches, the S2 nerves exiting the foramen were identified, followed out through the sciatic notch, and a wire was passed through this region. Three 2-0 silk ties were applied to the exposed portion of the S3 and S4 nerve roots, and the nerves were transected because they were integrally involved with the tumor. Using a series of high-speed burrs and osteotomes, lateral cuts were made through the sciatic notch. The sacrum was osteotomized at the S2 sacral foramen through the anterior component with an osteotome, while a hand protected the ventral structures. The remaining parts of the S3 and S4 dorsal nerve roots were transected. An incision through the peritoneum was made to access the rectus flap, and a plastic surgeon closed the wounds and secured the flap. 

Postoperative Course

The patient’s final pathology confirmed a chordoma with negative margins. Postoperatively, the rectus flap became ischemic and a wound infection developed. It was irrigated, débrided, and treated with vacuum-assisted closure (VAC), in addition to perioperative antibiotic administration. An abdominal computed tomography (CT) scan did not show any fistula, and her wound remained healthy, pink, and viable as her VAC was changed every 3 days. Because the patient’s nutritional status was compromised, she started nutritional supplements in addition to a regular diet. Physical therapy was prescribed and the patient began bladder training with self-catheterization after a failed voiding trial attempt. After 2 months of convalescence, the patient had mobilized well and had progressed to walking without an ambulatory aide.

At her third postoperative month, the patient noted new onset of extreme pain in the groin and left thigh regions. The patient was examined and appeared to have a stable neurological exam. She had reproducible pain with a FABER (Flexion, Abduction, External Rotation, and Extension) test. MRI showed increased signal on short tau inversion recovery (STIR) sequences and T2-weighted images that was consistent with a left sacral ala stress fracture with a vertically oriented fracture line (Figures 2A, 2B). The patient was asked to begin utilizing a walker for ambulatory assistance, but her weight-bearing status was not changed. Over the course of 3 months, the patient noted a resolution of her pain. All postoperative MRI images confirmed the patient to be disease-free; and in addition, all of her follow-up radiographs showed a stable pelvic ring (Figures 3A, 3B). At her 2-year follow-up, the patient remained disease- and pain-free.

Discussion

Full discussions of the mechanical considerations of a partial sacrectomy have been described previously^5-8; however, surgeons typically consider the need for lumbar-pelvic stabilization when the surgical resection requires a violation of the S1 body. Approximately two-thirds of sacral tumors occur at or below the level of the S2 body.⁸ These lesions of the caudal sacrum can sometimes be effectively resected with transverse partial sacrectomy. Great care is taken to resect only the portion of the sacrum necessary for local disease control, sparing as much of the sacroiliac joint and as many of the lumbosacral nerve roots as possible.

Under normal conditions, the sacroiliac articulation is stabilized by both its geometric interface and its extraordinarily strong ligaments. This spatial arrangement conveys stability primarily against caudal migration of the sacrum. The sacroiliac, sacrotuberous, sacrospinous, and lumbosacral ligaments, which are among the strongest ligaments in the body, primarily act to provide stability to the pelvic ring by preventing diastasis. The combination of these factors renders the spinopelvic segment especially stable. Previously, 2 biomechanical studies that specifically looked at extreme loading patterns to better understand the need for lumbar-pelvic instrumentation predicted a fracture pattern when there was an inability of the base of the sacral ala to resist shear.^8,9 This is precisely where our patient’s insufficiency fracture occurred.

To our knowledge, this is the first reported in vivo evidence of this fracture pattern. While this patient’s potential history of osteoporosis may have elevated or contributed to her risk for fracture, her preoperative bone densitometry, with T scores of -1.0 on the left and right femur necks and 0.8 on her L1-L4 anteroposterior spine, would argue against this risk factor. None of these values represent a truly osteoporotic patient. It would appear that our patient sustained the fracture pattern predicted by Hugate and colleagues.⁸

The edema seen on the MRI most likely represents a fracture; however, sacroiliitis and infection are also potential diagnoses. Because there was no tumor in this region on the preoperative scans, we thought that a residual tumor was unlikely. The signal changes seen on T2 MRI sequences represent edema. The use of a bone scan that detects healing bone may have been a useful additional study to confirm this fracture as opposed to sacroiliitis. A CT scan would have been a potentially useful study to provide detail of fracture displacement and the overall fracture pattern. Standing plain radiographs are best for viewing fracture displacement with weight-bearing.

Surgeons contemplating performing partial sacrectomies should bear in mind that, even with preservation of the S1 body, a potential for fracture exists as evidenced by our patient. In our opinion, this patient did not require instrumentation but a more gradual rehabilitation program.

Blastomycosis is a rare fungal infection that primarily produces acute lung infections but may on occasion disseminate to multiple sites, including the skin, bone, central nervous system (CNS), and oropharynx.^1-30 In the case of a primary infection of the lung, if there is a high index of suspicion and a thorough diagnostic workup, the diagnosis can be made from sputum or bronchoscopy.²⁴ Patients present with acute pneumonia that either resolves spontaneously or proceeds to chronic pneumonia with extrapulmonary spread to multiple organs, including the spine. Once vertebral involvement occurs, an untreated infection may result in vertebral body destruction and paraspinal and epidural abscess formation followed by neurologic injury and loss of structural integrity of the spine.^{11,13,17,23,27,29}

In this article, we present a case of blastomycosis of the vertebral body and provide a detailed review of the literature concerning this extremely rare infection of the spine. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 30-year-old African American man with known pulmonary blastomycosis, for which he had been treated with oral itraconazole 200 mg twice daily for 6 months, was admitted to the hospital with a 2-month history of mild thoracolumbar back pain. He reported transient numbness and tingling in the lower extremities but no weakness. He denied weight loss, fatigue, appetite loss, and significant night pain. On physical examination, he was alert and oriented, well nourished, and in no acute distress. Percussion revealed limited range of motion and pain. Further examination of the spine demonstrated no spasm, swelling, erythema, or drainage. The lower extremities had intact sensation, motor strength, reflexes, and pulses, and clonus was absent. White blood cell count was 8100 cells/μL (normal), erythrocyte sedimentation rate was 77 mm/h (normal range, 0-20 mm/h), and C-reactive protein level was 57.2 mg/L (normal, ≤ 10 mg/L). The patient was HIV-negative. Chest radiographs were normal except for a small pleural effusion. Radiographs showed a destructive lesion of T11 with an extensive paravertebral and retropleural abscess tracking a spinal level above and below with extension into the spinal canal (Figure 1).

As the patient had signs of spinal cord compression, he was taken to surgery for incision and drainage and culture procurement and corpectomy of T11 with autogenous rib graft. One week later, he was stabilized with posterior fusion and instrumentation (Figure 2). Gram stain of the specimen demonstrated broad-based budding yeast forms 15 to 20 micrometers in size, consistent with blastomycosis. Cultures were positive for Blastomyces dermatitidis. Histopathologic slides (Figure 3) of the surgical pathology specimen showed granulomatous inflammation. Oral itraconazole 200 mg twice daily was continued, as it has been found to be efficacious in treating immunocompetent patients with blastomycosis¹⁷ and is considered the medication of choice for non–life-threatening, non-CNS blastomycosis. (Intravenous amphotericin B was ruled out because of its known serious side effects, such as bone marrow suppression and renal function impairment¹⁰; itraconazole was the better alternative.) The patient was placed in a thoracolumbar orthosis and discharged. As the effect of presence of instrumentation in the setting of a fungal infection is unknown, it was deemed prudent to maintain the patient on chronic antifungal suppression. One year after surgery, computed tomography (CT) showed solid osseous bridging through the cage crossing the T11 vertebral body, from the inferior endplate of T10 through the superior endplate of T12 (Figure 4). In addition, there had been no recurrence of the spinal infection, and the patient was neurologically intact and doing well.

Discussion

North American blastomycosis (B dermatitidis) is a ubiquitous dimorphic fungus that occurs worldwide and on occasion causes serious infections in humans.^9,23,26,29 It was first characterized in 1894 by Gilchrist and Stokes (Gilchrist disease) when they recovered the fungus from the lung tissue of a patient.³ In North America, blastomycosis infections occur from central Canada to the Gulf Coast to east of the Mississippi River.^{2,5,7,8,13,14,17,21,22,24,27,29} Additional cases of the disease have been reported in Africa,^9,16,23,28 Asia,^12,19 and South America^7,8 (Table [on pages E270-E271]). Recent epidemiologic studies have linked transmission of the disease to bodies of water and have questioned previous reports of male predominance and racial preference for African Americans (Table).

Blastomycosis is acquired when inhaled fungus (airborne conidia spores) causes a primary pulmonary infection or, rarely, when there is direct inoculation through the skin. The differential diagnosis includes neoplasm, tuberculosis, actinomycosis, bacterial infections, cryptococcosis, and coccidioidomycosis.^{3,9,12,20,25,31} Blastomycosis occurs in adults and children.^1-30 The rate of mortality is much higher in immunocompromised patients. Initial symptoms include fever, chills, fatigue, malaise, myalgia, arthalgia, weight loss, and stigmata of chronic disease.^1-30 Acute pulmonary infection with blastomycosis generally resolves spontaneously but may progress to acute respiratory distress syndrome, which has a mortality rate of 50% to 89%.¹⁹ With systemic dissemination, the infection may spread to other organs¹¹—there is a particular predilection for the skin^9,20,29—and to the long bones^7,16 and the oropharynx.^16,26,28

In 50% to 64% of cases, bone involvement may be the first disease manifestation.^6,7,16,22 Osseous involvement with blastomycosis most commonly affects the long bones¹⁵ but may include the vertebrae,^1-29 the ribs,²⁶ and the carpal or tarsal bones.^7,16 The most common vertebral involvement occurs in the thoracic or lumbar spine^{1,2,7-9,11-14,17,19,21-24,26} and typically results in destruction of the body, development of a paraspinal abscess, and potential extension into the spinal canal, causing an epidural abscess and development of chronic draining cutaneous sinuses.^{2,7,9,11-13,16,17,19,22,23,26,28,29} In the present case, we do not know whether the vertebral body was involved before the patient presented with mid-thoracolumbar back pain. There may have been bony involvement during initial presentation.

Diagnosis is often difficult because of a low index of suspicion, leading to a significant delay in treatment. Primary pulmonary infections are successfully diagnosed 86% of the time from sputum and 92% of the time from bronchoscopy.¹⁹ Once the infection involves the spine, plain radiographs, CT, and magnetic resonance imaging (MRI) can be used to identify not only the bony involvement but also any adjacent soft-tissue extension.¹³ The radiographic findings, typical of tuberculosis or a neoplasm, include disc space narrowing, vertebral body destruction and collapse, late segmental kyphotic deformity, and development of a psoas abscess or a retropleural abscess.^7,26 Such abscesses lend themselves well to fine-needle aspiration,^{7,8,11,13,14,17,19,26} which, when combined with CT and MRI guidance, reliably assists in the diagnosis of blastomycosis.^1,13,17 If fine-needle aspiration fails, then open biopsy and surgical débridement specimens may be effective in the diagnosis.^{2,9,12,21,22,27}

The mortality rate for systemic blastomycosis exceeded 90% before the development of antifungal medications, and these medications remain the primary treatment for most initial infections.¹⁵ For severe infections in critically ill patients and for patients with CNS involvement, amphotericin B has been effective, with cure rates approaching 97%.¹⁷ Itraconazole, which is well tolerated, has replaced ketoconazole as the preferred long-term oral treatment for blastomycosis. Cure rates for itraconazole approach 90% when treatment is instituted over 2 years in a compliant patient.^10,19,20 Nonsurgical (antifungal) treatment for blastomycosis of the spine has also proved successful in neurologically intact patients.^7,9,11,26,28

A case involving the spine and requiring surgical drainage was first reported in 1908⁵; since then, only a few more cases have been reported.^{1,2,5,7-9,11-14,16,17,19,21-24,26-29} Thus, the literature includes very little information that can be used to establish indications for surgery for a blastomycotic infection of the spine. However, there is enough evidence to establish that surgery is indicated for patients who have a known blastomycosis infection and are developing neurologic or structural loss of integrity of the spinal column or have an abscess that requires drainage and débridement.

Our patient had been on long-term antifungal treatment but nevertheless developed a destructive spinal lesion with a concurrent epidural and retropleural abscess. Given his risk of pathologic fracture, we performed anterior débridement and stabilization followed by posterior fusion and instrumentation. We are unaware of any other cases in which an anterior titanium cage was combined with rib autograft after anterior débridement and vertebrectomy combined with posterior instrumentation for blastomycosis. This technique proved very useful, as it allowed for immediate stabilization of the spine. Therefore, the treatment goal is similar to that for any destructive infection that fails medical treatment: preservation of neurologic function, stabilization of spinal vertebrae, débridement of abscess cavity, and definitive culture procurement.

Conclusion

Although there is little reported information regarding surgical indications for blastomycotic vertebral osteomyelitis that has failed medical management—in patients with a destructive lesion and compromise of both the spinal canal and the integrity of the vertebral column—anterior débridement and stabilization followed by posterior fusion and instrumentation are useful in preventing vertebral collapse, further canal compromise, and possible cord injury.

Blastomycosis is a rare fungal infection that primarily produces acute lung infections but may on occasion disseminate to multiple sites, including the skin, bone, central nervous system (CNS), and oropharynx.^1-30 In the case of a primary infection of the lung, if there is a high index of suspicion and a thorough diagnostic workup, the diagnosis can be made from sputum or bronchoscopy.²⁴ Patients present with acute pneumonia that either resolves spontaneously or proceeds to chronic pneumonia with extrapulmonary spread to multiple organs, including the spine. Once vertebral involvement occurs, an untreated infection may result in vertebral body destruction and paraspinal and epidural abscess formation followed by neurologic injury and loss of structural integrity of the spine.^{11,13,17,23,27,29}

In this article, we present a case of blastomycosis of the vertebral body and provide a detailed review of the literature concerning this extremely rare infection of the spine. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 30-year-old African American man with known pulmonary blastomycosis, for which he had been treated with oral itraconazole 200 mg twice daily for 6 months, was admitted to the hospital with a 2-month history of mild thoracolumbar back pain. He reported transient numbness and tingling in the lower extremities but no weakness. He denied weight loss, fatigue, appetite loss, and significant night pain. On physical examination, he was alert and oriented, well nourished, and in no acute distress. Percussion revealed limited range of motion and pain. Further examination of the spine demonstrated no spasm, swelling, erythema, or drainage. The lower extremities had intact sensation, motor strength, reflexes, and pulses, and clonus was absent. White blood cell count was 8100 cells/μL (normal), erythrocyte sedimentation rate was 77 mm/h (normal range, 0-20 mm/h), and C-reactive protein level was 57.2 mg/L (normal, ≤ 10 mg/L). The patient was HIV-negative. Chest radiographs were normal except for a small pleural effusion. Radiographs showed a destructive lesion of T11 with an extensive paravertebral and retropleural abscess tracking a spinal level above and below with extension into the spinal canal (Figure 1).

As the patient had signs of spinal cord compression, he was taken to surgery for incision and drainage and culture procurement and corpectomy of T11 with autogenous rib graft. One week later, he was stabilized with posterior fusion and instrumentation (Figure 2). Gram stain of the specimen demonstrated broad-based budding yeast forms 15 to 20 micrometers in size, consistent with blastomycosis. Cultures were positive for Blastomyces dermatitidis. Histopathologic slides (Figure 3) of the surgical pathology specimen showed granulomatous inflammation. Oral itraconazole 200 mg twice daily was continued, as it has been found to be efficacious in treating immunocompetent patients with blastomycosis¹⁷ and is considered the medication of choice for non–life-threatening, non-CNS blastomycosis. (Intravenous amphotericin B was ruled out because of its known serious side effects, such as bone marrow suppression and renal function impairment¹⁰; itraconazole was the better alternative.) The patient was placed in a thoracolumbar orthosis and discharged. As the effect of presence of instrumentation in the setting of a fungal infection is unknown, it was deemed prudent to maintain the patient on chronic antifungal suppression. One year after surgery, computed tomography (CT) showed solid osseous bridging through the cage crossing the T11 vertebral body, from the inferior endplate of T10 through the superior endplate of T12 (Figure 4). In addition, there had been no recurrence of the spinal infection, and the patient was neurologically intact and doing well.

Discussion

North American blastomycosis (B dermatitidis) is a ubiquitous dimorphic fungus that occurs worldwide and on occasion causes serious infections in humans.^9,23,26,29 It was first characterized in 1894 by Gilchrist and Stokes (Gilchrist disease) when they recovered the fungus from the lung tissue of a patient.³ In North America, blastomycosis infections occur from central Canada to the Gulf Coast to east of the Mississippi River.^{2,5,7,8,13,14,17,21,22,24,27,29} Additional cases of the disease have been reported in Africa,^9,16,23,28 Asia,^12,19 and South America^7,8 (Table [on pages E270-E271]). Recent epidemiologic studies have linked transmission of the disease to bodies of water and have questioned previous reports of male predominance and racial preference for African Americans (Table).

Blastomycosis is acquired when inhaled fungus (airborne conidia spores) causes a primary pulmonary infection or, rarely, when there is direct inoculation through the skin. The differential diagnosis includes neoplasm, tuberculosis, actinomycosis, bacterial infections, cryptococcosis, and coccidioidomycosis.^{3,9,12,20,25,31} Blastomycosis occurs in adults and children.^1-30 The rate of mortality is much higher in immunocompromised patients. Initial symptoms include fever, chills, fatigue, malaise, myalgia, arthalgia, weight loss, and stigmata of chronic disease.^1-30 Acute pulmonary infection with blastomycosis generally resolves spontaneously but may progress to acute respiratory distress syndrome, which has a mortality rate of 50% to 89%.¹⁹ With systemic dissemination, the infection may spread to other organs¹¹—there is a particular predilection for the skin^9,20,29—and to the long bones^7,16 and the oropharynx.^16,26,28

In 50% to 64% of cases, bone involvement may be the first disease manifestation.^6,7,16,22 Osseous involvement with blastomycosis most commonly affects the long bones¹⁵ but may include the vertebrae,^1-29 the ribs,²⁶ and the carpal or tarsal bones.^7,16 The most common vertebral involvement occurs in the thoracic or lumbar spine^{1,2,7-9,11-14,17,19,21-24,26} and typically results in destruction of the body, development of a paraspinal abscess, and potential extension into the spinal canal, causing an epidural abscess and development of chronic draining cutaneous sinuses.^{2,7,9,11-13,16,17,19,22,23,26,28,29} In the present case, we do not know whether the vertebral body was involved before the patient presented with mid-thoracolumbar back pain. There may have been bony involvement during initial presentation.

Diagnosis is often difficult because of a low index of suspicion, leading to a significant delay in treatment. Primary pulmonary infections are successfully diagnosed 86% of the time from sputum and 92% of the time from bronchoscopy.¹⁹ Once the infection involves the spine, plain radiographs, CT, and magnetic resonance imaging (MRI) can be used to identify not only the bony involvement but also any adjacent soft-tissue extension.¹³ The radiographic findings, typical of tuberculosis or a neoplasm, include disc space narrowing, vertebral body destruction and collapse, late segmental kyphotic deformity, and development of a psoas abscess or a retropleural abscess.^7,26 Such abscesses lend themselves well to fine-needle aspiration,^{7,8,11,13,14,17,19,26} which, when combined with CT and MRI guidance, reliably assists in the diagnosis of blastomycosis.^1,13,17 If fine-needle aspiration fails, then open biopsy and surgical débridement specimens may be effective in the diagnosis.^{2,9,12,21,22,27}

The mortality rate for systemic blastomycosis exceeded 90% before the development of antifungal medications, and these medications remain the primary treatment for most initial infections.¹⁵ For severe infections in critically ill patients and for patients with CNS involvement, amphotericin B has been effective, with cure rates approaching 97%.¹⁷ Itraconazole, which is well tolerated, has replaced ketoconazole as the preferred long-term oral treatment for blastomycosis. Cure rates for itraconazole approach 90% when treatment is instituted over 2 years in a compliant patient.^10,19,20 Nonsurgical (antifungal) treatment for blastomycosis of the spine has also proved successful in neurologically intact patients.^7,9,11,26,28

A case involving the spine and requiring surgical drainage was first reported in 1908⁵; since then, only a few more cases have been reported.^{1,2,5,7-9,11-14,16,17,19,21-24,26-29} Thus, the literature includes very little information that can be used to establish indications for surgery for a blastomycotic infection of the spine. However, there is enough evidence to establish that surgery is indicated for patients who have a known blastomycosis infection and are developing neurologic or structural loss of integrity of the spinal column or have an abscess that requires drainage and débridement.

Our patient had been on long-term antifungal treatment but nevertheless developed a destructive spinal lesion with a concurrent epidural and retropleural abscess. Given his risk of pathologic fracture, we performed anterior débridement and stabilization followed by posterior fusion and instrumentation. We are unaware of any other cases in which an anterior titanium cage was combined with rib autograft after anterior débridement and vertebrectomy combined with posterior instrumentation for blastomycosis. This technique proved very useful, as it allowed for immediate stabilization of the spine. Therefore, the treatment goal is similar to that for any destructive infection that fails medical treatment: preservation of neurologic function, stabilization of spinal vertebrae, débridement of abscess cavity, and definitive culture procurement.

Conclusion

Although there is little reported information regarding surgical indications for blastomycotic vertebral osteomyelitis that has failed medical management—in patients with a destructive lesion and compromise of both the spinal canal and the integrity of the vertebral column—anterior débridement and stabilization followed by posterior fusion and instrumentation are useful in preventing vertebral collapse, further canal compromise, and possible cord injury.

Blastomycosis is a rare fungal infection that primarily produces acute lung infections but may on occasion disseminate to multiple sites, including the skin, bone, central nervous system (CNS), and oropharynx.^1-30 In the case of a primary infection of the lung, if there is a high index of suspicion and a thorough diagnostic workup, the diagnosis can be made from sputum or bronchoscopy.²⁴ Patients present with acute pneumonia that either resolves spontaneously or proceeds to chronic pneumonia with extrapulmonary spread to multiple organs, including the spine. Once vertebral involvement occurs, an untreated infection may result in vertebral body destruction and paraspinal and epidural abscess formation followed by neurologic injury and loss of structural integrity of the spine.^{11,13,17,23,27,29}

In this article, we present a case of blastomycosis of the vertebral body and provide a detailed review of the literature concerning this extremely rare infection of the spine. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 30-year-old African American man with known pulmonary blastomycosis, for which he had been treated with oral itraconazole 200 mg twice daily for 6 months, was admitted to the hospital with a 2-month history of mild thoracolumbar back pain. He reported transient numbness and tingling in the lower extremities but no weakness. He denied weight loss, fatigue, appetite loss, and significant night pain. On physical examination, he was alert and oriented, well nourished, and in no acute distress. Percussion revealed limited range of motion and pain. Further examination of the spine demonstrated no spasm, swelling, erythema, or drainage. The lower extremities had intact sensation, motor strength, reflexes, and pulses, and clonus was absent. White blood cell count was 8100 cells/μL (normal), erythrocyte sedimentation rate was 77 mm/h (normal range, 0-20 mm/h), and C-reactive protein level was 57.2 mg/L (normal, ≤ 10 mg/L). The patient was HIV-negative. Chest radiographs were normal except for a small pleural effusion. Radiographs showed a destructive lesion of T11 with an extensive paravertebral and retropleural abscess tracking a spinal level above and below with extension into the spinal canal (Figure 1).

As the patient had signs of spinal cord compression, he was taken to surgery for incision and drainage and culture procurement and corpectomy of T11 with autogenous rib graft. One week later, he was stabilized with posterior fusion and instrumentation (Figure 2). Gram stain of the specimen demonstrated broad-based budding yeast forms 15 to 20 micrometers in size, consistent with blastomycosis. Cultures were positive for Blastomyces dermatitidis. Histopathologic slides (Figure 3) of the surgical pathology specimen showed granulomatous inflammation. Oral itraconazole 200 mg twice daily was continued, as it has been found to be efficacious in treating immunocompetent patients with blastomycosis¹⁷ and is considered the medication of choice for non–life-threatening, non-CNS blastomycosis. (Intravenous amphotericin B was ruled out because of its known serious side effects, such as bone marrow suppression and renal function impairment¹⁰; itraconazole was the better alternative.) The patient was placed in a thoracolumbar orthosis and discharged. As the effect of presence of instrumentation in the setting of a fungal infection is unknown, it was deemed prudent to maintain the patient on chronic antifungal suppression. One year after surgery, computed tomography (CT) showed solid osseous bridging through the cage crossing the T11 vertebral body, from the inferior endplate of T10 through the superior endplate of T12 (Figure 4). In addition, there had been no recurrence of the spinal infection, and the patient was neurologically intact and doing well.

Discussion

North American blastomycosis (B dermatitidis) is a ubiquitous dimorphic fungus that occurs worldwide and on occasion causes serious infections in humans.^9,23,26,29 It was first characterized in 1894 by Gilchrist and Stokes (Gilchrist disease) when they recovered the fungus from the lung tissue of a patient.³ In North America, blastomycosis infections occur from central Canada to the Gulf Coast to east of the Mississippi River.^{2,5,7,8,13,14,17,21,22,24,27,29} Additional cases of the disease have been reported in Africa,^9,16,23,28 Asia,^12,19 and South America^7,8 (Table [on pages E270-E271]). Recent epidemiologic studies have linked transmission of the disease to bodies of water and have questioned previous reports of male predominance and racial preference for African Americans (Table).

Blastomycosis is acquired when inhaled fungus (airborne conidia spores) causes a primary pulmonary infection or, rarely, when there is direct inoculation through the skin. The differential diagnosis includes neoplasm, tuberculosis, actinomycosis, bacterial infections, cryptococcosis, and coccidioidomycosis.^{3,9,12,20,25,31} Blastomycosis occurs in adults and children.^1-30 The rate of mortality is much higher in immunocompromised patients. Initial symptoms include fever, chills, fatigue, malaise, myalgia, arthalgia, weight loss, and stigmata of chronic disease.^1-30 Acute pulmonary infection with blastomycosis generally resolves spontaneously but may progress to acute respiratory distress syndrome, which has a mortality rate of 50% to 89%.¹⁹ With systemic dissemination, the infection may spread to other organs¹¹—there is a particular predilection for the skin^9,20,29—and to the long bones^7,16 and the oropharynx.^16,26,28

In 50% to 64% of cases, bone involvement may be the first disease manifestation.^6,7,16,22 Osseous involvement with blastomycosis most commonly affects the long bones¹⁵ but may include the vertebrae,^1-29 the ribs,²⁶ and the carpal or tarsal bones.^7,16 The most common vertebral involvement occurs in the thoracic or lumbar spine^{1,2,7-9,11-14,17,19,21-24,26} and typically results in destruction of the body, development of a paraspinal abscess, and potential extension into the spinal canal, causing an epidural abscess and development of chronic draining cutaneous sinuses.^{2,7,9,11-13,16,17,19,22,23,26,28,29} In the present case, we do not know whether the vertebral body was involved before the patient presented with mid-thoracolumbar back pain. There may have been bony involvement during initial presentation.

Diagnosis is often difficult because of a low index of suspicion, leading to a significant delay in treatment. Primary pulmonary infections are successfully diagnosed 86% of the time from sputum and 92% of the time from bronchoscopy.¹⁹ Once the infection involves the spine, plain radiographs, CT, and magnetic resonance imaging (MRI) can be used to identify not only the bony involvement but also any adjacent soft-tissue extension.¹³ The radiographic findings, typical of tuberculosis or a neoplasm, include disc space narrowing, vertebral body destruction and collapse, late segmental kyphotic deformity, and development of a psoas abscess or a retropleural abscess.^7,26 Such abscesses lend themselves well to fine-needle aspiration,^{7,8,11,13,14,17,19,26} which, when combined with CT and MRI guidance, reliably assists in the diagnosis of blastomycosis.^1,13,17 If fine-needle aspiration fails, then open biopsy and surgical débridement specimens may be effective in the diagnosis.^{2,9,12,21,22,27}

The mortality rate for systemic blastomycosis exceeded 90% before the development of antifungal medications, and these medications remain the primary treatment for most initial infections.¹⁵ For severe infections in critically ill patients and for patients with CNS involvement, amphotericin B has been effective, with cure rates approaching 97%.¹⁷ Itraconazole, which is well tolerated, has replaced ketoconazole as the preferred long-term oral treatment for blastomycosis. Cure rates for itraconazole approach 90% when treatment is instituted over 2 years in a compliant patient.^10,19,20 Nonsurgical (antifungal) treatment for blastomycosis of the spine has also proved successful in neurologically intact patients.^7,9,11,26,28

A case involving the spine and requiring surgical drainage was first reported in 1908⁵; since then, only a few more cases have been reported.^{1,2,5,7-9,11-14,16,17,19,21-24,26-29} Thus, the literature includes very little information that can be used to establish indications for surgery for a blastomycotic infection of the spine. However, there is enough evidence to establish that surgery is indicated for patients who have a known blastomycosis infection and are developing neurologic or structural loss of integrity of the spinal column or have an abscess that requires drainage and débridement.

Our patient had been on long-term antifungal treatment but nevertheless developed a destructive spinal lesion with a concurrent epidural and retropleural abscess. Given his risk of pathologic fracture, we performed anterior débridement and stabilization followed by posterior fusion and instrumentation. We are unaware of any other cases in which an anterior titanium cage was combined with rib autograft after anterior débridement and vertebrectomy combined with posterior instrumentation for blastomycosis. This technique proved very useful, as it allowed for immediate stabilization of the spine. Therefore, the treatment goal is similar to that for any destructive infection that fails medical treatment: preservation of neurologic function, stabilization of spinal vertebrae, débridement of abscess cavity, and definitive culture procurement.

Conclusion

Although there is little reported information regarding surgical indications for blastomycotic vertebral osteomyelitis that has failed medical management—in patients with a destructive lesion and compromise of both the spinal canal and the integrity of the vertebral column—anterior débridement and stabilization followed by posterior fusion and instrumentation are useful in preventing vertebral collapse, further canal compromise, and possible cord injury.