Consider facet joint OA in older patients with low back pain

DESTIN, FLA. – Facet joint osteoarthritis likely accounts for much of what is classified as "nonspecific" low back pain, according to Dr. Alfred C. Gellhorn.

"Amazingly – and I think sadly for us – the lumbar facet joints really have received very little attention in the literature," Dr. Gellhorn, who works in the department of rehabilitation medicine at the University of Washington, Seattle, said at the annual Congress of Clinical Rheumatology.

Eight of every ten American will experience low back pain at some point during their lifetime; low back pain is second only to the common cold in frequency, is the most common reason for time off work, and has a total social cost of more than $100 billion annually. Up to 85% of patients never receive a definitive diagnosis and are classified has having nonspecific pain, he said.

©Rocky89/thinkstockphotos.com

The facet joints may be responsible for a significant proportion of that pain.

Facet joint cartilage is aneural, but a number of nociceptors exist in the subchondral bone, the synovial folds, and the capsule. Once activated – by synovial inflammation or mechanical factors such as trabecular microfractures, capsular distention, pressure on the subchondral bone as joint load increases, or intramedullary hypertension, for example – the nociceptors may cause secondary reflex contraction of paraspinal muscles.

Patients will report this as spasms, and the contractions can be palpated, Dr. Gellhorn said, noting that prolonged inflammation in and around the facet joints can lead to central sensitization, neuronal plasticity, and development of chronic low back pain.

Facet joint osteoarthritis (OA) is distinct from disc degeneration, but the two conditions are interdependent. Radiographic hallmarks of disc degeneration include disc height loss, dehydration, and endplate sclerosis, whereas radiographic hallmarks of facet joint OA include narrowing of the facet joint space, osteophytosis of articular processes, hypertrophy of articular processes, sclerosis, subchondral erosion, and subchondral cysts.

Older studies that looked at facet joint OA by comparing findings on imaging and symptoms found either no association or only minimal association between facet joint OA and low back pain, but the threshold used in those studies was mild to moderate OA in young and middle-aged subjects.

"That’s the wrong criterion to use," Dr. Gellhorn said, noting that mild facet joint OA is "essentially ubiquitous" by middle age. Moderate to severe facet OA, however, is more symptomatic, and predominantly affects older adults – and should be the criterion used in studies of the condition.

In a recent study of 252 patients with a mean age of 67 years who were participants in the Framingham heart study, severe OA affecting the facet joint was significantly associated with frequent low back pain (odds ratio, 2.2). Disc height narrowing was not associated with low back pain in these patients (Osteoarthritis Cartilage 2013;21:1199-206).

The findings contrast with those from prior studies, likely because the cohort was older (mean age of 67 years vs. 30s to 50s), he said.

It may be that with age, back pain classified as "nonspecific" shifts from discogenic pain in younger adults to facetogenic pain in older adults, he suggested.

Findings with respect to disc pathology and low back pain in young and middle-aged adults seem to support this hypothesis, he noted.

For example, in a study of patients with a mean age of 49 years, low back pain was associated with a twofold increased likelihood of disc height loss and annular tears, and in a study of patients aged 18-50 years, moderate disc height loss was also associated with a twofold increased likelihood of low back pain. In another study of patients with a mean age of 50 years, advanced disc height loss was associated with a threefold increased likelihood of prevalent low back pain.

In another study, severe disc height narrowing was associated with a threefold increase in the odds of low back pain in those younger than age 60 years but not in those over age 60 years.

There are markers for symptomatic facet joint OA. Despite the known association between severe facet joint OA and low back pain, "the truth is there is still limited positive predictive value for that," he said.

"Many older adults with severe facet joint OA on imaging are relatively asymptomatic," he added.

There are some additional imaging makers, however. Symptomatic facet join OA is apparent on single-photon emission computed tomography/computed tomography (SPECT/CT) or fluid-sensitive, fat-suppressed MRI. Also, 64% of patients with suspected facet joint pain in one study had bone marrow lesions on short T1 inversion recovery (STIR) MRI, which were well correlated to the side of pain, he said.

There are no serum biomarkers for the condition at present, he noted.

In addition to older age and these findings on imaging, other risk factors and correlates for facet joint OA include sex (women are 1.5-1.9 times more likely than men to have facet joint OA), race (African Americans are about 60% less likely than white Americans to have facet joint OA), and high body mass index (those with BMI of 25-30 and 30-35 have a three- and fivefold increased risk of lumbar pain associated with facet joint OA, respectively, compared with those with BMI below 25).

Abdominal aortic calcifications and more sagittal orientation of the joints (vs. coronal orientation), also are associated with facet joint OA, Dr. Gellhorn said.

With additional research, these factors could be useful for "disambiguating nonspecific low back pain," he said.

"I think we’re getting closer. We’re not there yet, but we’re getting closer," he said.

Clinically, facet joint OA often presents as localized back or neck pain at C5-C6 with some radiation into the scapular region.

"It’s less clear in the lumbar spine, but almost always people will have pain in the lumbar region, and almost always they will have pain that radiates into the buttocks," he said, noting that pain radiating into the anterior or lateral thighs can be associated with facet joint OA, but pain that extends below the knees is more likely to be radicular.

There are no specific examination maneuvers that are pathognomonic – or even particularly helpful – for the condition, he added.

It is important to keep in mind that many patients will have associated conditions, including spondylolisthesis, disc degeneration, scoliosis, muscle atrophy, and spinal stenosis.

"It’s easy to get overwhelmed in the face of this, but I would urge you not to, and to still try to disentangle some of these concepts of low back pain without throwing up your hands," he said.

Although anesthetic blockade of the medial branches of the dorsal primary ramus (or "medial branch blocks,") are considered the gold standard for diagnosis, they are controversial, have an unacceptably high rate of false-positive results with a single block, and thus may require comparative blocks, which can result in numerous spinal injections.

This is problematic; there is no good way to make the diagnosis before doing more rational, conservative treatment, he said.

"I think that there are probably better things than doing 30 injections into someone’s spine to establish a diagnosis," he said.

In fact, treatment for facet joint OA generally involves physical activity.

"You don’t want to push these people to their limits, but certainly it is important to have them move and to have them keep the strength in their spine," he said.

In the absence of good studies evaluating noninterventional therapy for confirmed facet joint pain, treatment is generally based on findings in patients with chronic nonspecific low back pain and knee OA, and there is evidence in both of those settings that suggest exercise is helpful for increasing strength and decreasing pain and disability.

A Cochrane review showed that exercise therapy provides mild to moderate benefit. Additional studies have suggested that early referral to physical therapy results in modest improvement in function at 12 months in older adults, suggesting physical therapy provides longer-term results than many other interventions for low back pain, which tend to provide only short-term relief, he noted.

Furthermore, patients who have physical therapy tend to require fewer interventions. Dr. Gellhorn found in a recent study that physical therapy in a Medicare population with low back pain was associated with fewer lumbar injections, physician office visits, and lumbar surgeries.

"So it’s very reasonable to send your patients with facet joint OA to PT," he said.

Other treatments that may have some benefit if physical activity is inadequate include intra-articular steroid injections and radiofrequency denervation.

In studies that used SPECT for inclusion criteria, intra-articular injections were better than medial branch blocks at 3 months, and were more effective at 1 month and 3 months than were injections used in studies that did not use SPECT for inclusion, he said.

Injections were not useful in studies that used physical examination or diagnostic block for inclusion.

"So if you’re basing it on metabolic activity, you’re likely to have a good outcome from your injection," he said.

Radiofrequency denervation tends to work better in the cervical spine than in the lumbar spine, but it is difficult to justify in practice because it requires medial branch block, or double or even triple block to optimize success, and because it is associated with a number of potential complications, such as loss of innervation to the multifidus muscles.

In his practice he first screens for red flags in patients who present with low back pain. Next, he gets an X-ray to look for alignment issues, and he "heavily considers – if the clinical picture fits" – whether facet joint OA might be the cause of the pain.

"I’ll talk to them about it, and then almost always, I’ll send them for an empiric trial of physical therapy plus or minus some analgesics – Tylenol or NSAIDs," he said.

If patients experience improved function and a decrease in symptoms within 6-8 weeks, he recommends that they begin a more interesting (than their home physical therapy regimen) exercise program, such as yoga or Pilates to help them maintain those gains; if they remain symptomatic, he images them.

He starts with SPECT/CT rather than MRI if facet joint OA is high on his differential list for the patient, and if that’s positive, he will consider intra-articular steroid injections. If the injections are effective he recommends yoga and/or Pilates for maintaining the gains.

In rare cases a patient doesn’t respond to the injections, and then he will consider more aggressive treatment, such as medial branch block or radiofrequency denervation.

Understanding of facet joint OA has been slow to emerge, but progress is being made, Dr. Gellhorn said.

For example, the work with SPECT/CT and STIR MRI is very exciting, he said.

"I think this is going to give us a number of things to work with: first and foremost, it’s going to give us better criteria to diagnose patients and enroll them in treatment studies," he said.

Serum, urine, and genetic biomarkers, on the other hand, are interesting and on the horizon, "but we’re not really there yet," he added.

"But I think we will be able to at least use imaging studies to monitor some response to treatment," he said.

Additional study is also needed with respect to conservative treatments. Studies comparing different exercise programs, including studies comparing strength vs. flexibility and extension vs. flexion, are needed.

Regenerative treatments, such as platelet rich plasma and autologous stem cells are another area of interest, he said.

Dr. Gellhorn reported having no disclosures.

DESTIN, FLA. – Facet joint osteoarthritis likely accounts for much of what is classified as "nonspecific" low back pain, according to Dr. Alfred C. Gellhorn.

"Amazingly – and I think sadly for us – the lumbar facet joints really have received very little attention in the literature," Dr. Gellhorn, who works in the department of rehabilitation medicine at the University of Washington, Seattle, said at the annual Congress of Clinical Rheumatology.

Eight of every ten American will experience low back pain at some point during their lifetime; low back pain is second only to the common cold in frequency, is the most common reason for time off work, and has a total social cost of more than $100 billion annually. Up to 85% of patients never receive a definitive diagnosis and are classified has having nonspecific pain, he said.

©Rocky89/thinkstockphotos.com

The facet joints may be responsible for a significant proportion of that pain.

Facet joint cartilage is aneural, but a number of nociceptors exist in the subchondral bone, the synovial folds, and the capsule. Once activated – by synovial inflammation or mechanical factors such as trabecular microfractures, capsular distention, pressure on the subchondral bone as joint load increases, or intramedullary hypertension, for example – the nociceptors may cause secondary reflex contraction of paraspinal muscles.

Patients will report this as spasms, and the contractions can be palpated, Dr. Gellhorn said, noting that prolonged inflammation in and around the facet joints can lead to central sensitization, neuronal plasticity, and development of chronic low back pain.

Facet joint osteoarthritis (OA) is distinct from disc degeneration, but the two conditions are interdependent. Radiographic hallmarks of disc degeneration include disc height loss, dehydration, and endplate sclerosis, whereas radiographic hallmarks of facet joint OA include narrowing of the facet joint space, osteophytosis of articular processes, hypertrophy of articular processes, sclerosis, subchondral erosion, and subchondral cysts.

Older studies that looked at facet joint OA by comparing findings on imaging and symptoms found either no association or only minimal association between facet joint OA and low back pain, but the threshold used in those studies was mild to moderate OA in young and middle-aged subjects.

"That’s the wrong criterion to use," Dr. Gellhorn said, noting that mild facet joint OA is "essentially ubiquitous" by middle age. Moderate to severe facet OA, however, is more symptomatic, and predominantly affects older adults – and should be the criterion used in studies of the condition.

In a recent study of 252 patients with a mean age of 67 years who were participants in the Framingham heart study, severe OA affecting the facet joint was significantly associated with frequent low back pain (odds ratio, 2.2). Disc height narrowing was not associated with low back pain in these patients (Osteoarthritis Cartilage 2013;21:1199-206).

The findings contrast with those from prior studies, likely because the cohort was older (mean age of 67 years vs. 30s to 50s), he said.

It may be that with age, back pain classified as "nonspecific" shifts from discogenic pain in younger adults to facetogenic pain in older adults, he suggested.

Findings with respect to disc pathology and low back pain in young and middle-aged adults seem to support this hypothesis, he noted.

For example, in a study of patients with a mean age of 49 years, low back pain was associated with a twofold increased likelihood of disc height loss and annular tears, and in a study of patients aged 18-50 years, moderate disc height loss was also associated with a twofold increased likelihood of low back pain. In another study of patients with a mean age of 50 years, advanced disc height loss was associated with a threefold increased likelihood of prevalent low back pain.

In another study, severe disc height narrowing was associated with a threefold increase in the odds of low back pain in those younger than age 60 years but not in those over age 60 years.

There are markers for symptomatic facet joint OA. Despite the known association between severe facet joint OA and low back pain, "the truth is there is still limited positive predictive value for that," he said.

"Many older adults with severe facet joint OA on imaging are relatively asymptomatic," he added.

There are some additional imaging makers, however. Symptomatic facet join OA is apparent on single-photon emission computed tomography/computed tomography (SPECT/CT) or fluid-sensitive, fat-suppressed MRI. Also, 64% of patients with suspected facet joint pain in one study had bone marrow lesions on short T1 inversion recovery (STIR) MRI, which were well correlated to the side of pain, he said.

There are no serum biomarkers for the condition at present, he noted.

In addition to older age and these findings on imaging, other risk factors and correlates for facet joint OA include sex (women are 1.5-1.9 times more likely than men to have facet joint OA), race (African Americans are about 60% less likely than white Americans to have facet joint OA), and high body mass index (those with BMI of 25-30 and 30-35 have a three- and fivefold increased risk of lumbar pain associated with facet joint OA, respectively, compared with those with BMI below 25).

Abdominal aortic calcifications and more sagittal orientation of the joints (vs. coronal orientation), also are associated with facet joint OA, Dr. Gellhorn said.

With additional research, these factors could be useful for "disambiguating nonspecific low back pain," he said.

"I think we’re getting closer. We’re not there yet, but we’re getting closer," he said.

Clinically, facet joint OA often presents as localized back or neck pain at C5-C6 with some radiation into the scapular region.

"It’s less clear in the lumbar spine, but almost always people will have pain in the lumbar region, and almost always they will have pain that radiates into the buttocks," he said, noting that pain radiating into the anterior or lateral thighs can be associated with facet joint OA, but pain that extends below the knees is more likely to be radicular.

There are no specific examination maneuvers that are pathognomonic – or even particularly helpful – for the condition, he added.

It is important to keep in mind that many patients will have associated conditions, including spondylolisthesis, disc degeneration, scoliosis, muscle atrophy, and spinal stenosis.

"It’s easy to get overwhelmed in the face of this, but I would urge you not to, and to still try to disentangle some of these concepts of low back pain without throwing up your hands," he said.

Although anesthetic blockade of the medial branches of the dorsal primary ramus (or "medial branch blocks,") are considered the gold standard for diagnosis, they are controversial, have an unacceptably high rate of false-positive results with a single block, and thus may require comparative blocks, which can result in numerous spinal injections.

This is problematic; there is no good way to make the diagnosis before doing more rational, conservative treatment, he said.

"I think that there are probably better things than doing 30 injections into someone’s spine to establish a diagnosis," he said.

In fact, treatment for facet joint OA generally involves physical activity.

"You don’t want to push these people to their limits, but certainly it is important to have them move and to have them keep the strength in their spine," he said.

In the absence of good studies evaluating noninterventional therapy for confirmed facet joint pain, treatment is generally based on findings in patients with chronic nonspecific low back pain and knee OA, and there is evidence in both of those settings that suggest exercise is helpful for increasing strength and decreasing pain and disability.

A Cochrane review showed that exercise therapy provides mild to moderate benefit. Additional studies have suggested that early referral to physical therapy results in modest improvement in function at 12 months in older adults, suggesting physical therapy provides longer-term results than many other interventions for low back pain, which tend to provide only short-term relief, he noted.

Furthermore, patients who have physical therapy tend to require fewer interventions. Dr. Gellhorn found in a recent study that physical therapy in a Medicare population with low back pain was associated with fewer lumbar injections, physician office visits, and lumbar surgeries.

"So it’s very reasonable to send your patients with facet joint OA to PT," he said.

Other treatments that may have some benefit if physical activity is inadequate include intra-articular steroid injections and radiofrequency denervation.

In studies that used SPECT for inclusion criteria, intra-articular injections were better than medial branch blocks at 3 months, and were more effective at 1 month and 3 months than were injections used in studies that did not use SPECT for inclusion, he said.

Injections were not useful in studies that used physical examination or diagnostic block for inclusion.

"So if you’re basing it on metabolic activity, you’re likely to have a good outcome from your injection," he said.

Radiofrequency denervation tends to work better in the cervical spine than in the lumbar spine, but it is difficult to justify in practice because it requires medial branch block, or double or even triple block to optimize success, and because it is associated with a number of potential complications, such as loss of innervation to the multifidus muscles.

In his practice he first screens for red flags in patients who present with low back pain. Next, he gets an X-ray to look for alignment issues, and he "heavily considers – if the clinical picture fits" – whether facet joint OA might be the cause of the pain.

"I’ll talk to them about it, and then almost always, I’ll send them for an empiric trial of physical therapy plus or minus some analgesics – Tylenol or NSAIDs," he said.

If patients experience improved function and a decrease in symptoms within 6-8 weeks, he recommends that they begin a more interesting (than their home physical therapy regimen) exercise program, such as yoga or Pilates to help them maintain those gains; if they remain symptomatic, he images them.

He starts with SPECT/CT rather than MRI if facet joint OA is high on his differential list for the patient, and if that’s positive, he will consider intra-articular steroid injections. If the injections are effective he recommends yoga and/or Pilates for maintaining the gains.

In rare cases a patient doesn’t respond to the injections, and then he will consider more aggressive treatment, such as medial branch block or radiofrequency denervation.

Understanding of facet joint OA has been slow to emerge, but progress is being made, Dr. Gellhorn said.

For example, the work with SPECT/CT and STIR MRI is very exciting, he said.

"I think this is going to give us a number of things to work with: first and foremost, it’s going to give us better criteria to diagnose patients and enroll them in treatment studies," he said.

Serum, urine, and genetic biomarkers, on the other hand, are interesting and on the horizon, "but we’re not really there yet," he added.

"But I think we will be able to at least use imaging studies to monitor some response to treatment," he said.

Additional study is also needed with respect to conservative treatments. Studies comparing different exercise programs, including studies comparing strength vs. flexibility and extension vs. flexion, are needed.

Regenerative treatments, such as platelet rich plasma and autologous stem cells are another area of interest, he said.

Dr. Gellhorn reported having no disclosures.

DESTIN, FLA. – Facet joint osteoarthritis likely accounts for much of what is classified as "nonspecific" low back pain, according to Dr. Alfred C. Gellhorn.

"Amazingly – and I think sadly for us – the lumbar facet joints really have received very little attention in the literature," Dr. Gellhorn, who works in the department of rehabilitation medicine at the University of Washington, Seattle, said at the annual Congress of Clinical Rheumatology.

Eight of every ten American will experience low back pain at some point during their lifetime; low back pain is second only to the common cold in frequency, is the most common reason for time off work, and has a total social cost of more than $100 billion annually. Up to 85% of patients never receive a definitive diagnosis and are classified has having nonspecific pain, he said.

©Rocky89/thinkstockphotos.com

The facet joints may be responsible for a significant proportion of that pain.

Facet joint cartilage is aneural, but a number of nociceptors exist in the subchondral bone, the synovial folds, and the capsule. Once activated – by synovial inflammation or mechanical factors such as trabecular microfractures, capsular distention, pressure on the subchondral bone as joint load increases, or intramedullary hypertension, for example – the nociceptors may cause secondary reflex contraction of paraspinal muscles.

Patients will report this as spasms, and the contractions can be palpated, Dr. Gellhorn said, noting that prolonged inflammation in and around the facet joints can lead to central sensitization, neuronal plasticity, and development of chronic low back pain.

Facet joint osteoarthritis (OA) is distinct from disc degeneration, but the two conditions are interdependent. Radiographic hallmarks of disc degeneration include disc height loss, dehydration, and endplate sclerosis, whereas radiographic hallmarks of facet joint OA include narrowing of the facet joint space, osteophytosis of articular processes, hypertrophy of articular processes, sclerosis, subchondral erosion, and subchondral cysts.

Older studies that looked at facet joint OA by comparing findings on imaging and symptoms found either no association or only minimal association between facet joint OA and low back pain, but the threshold used in those studies was mild to moderate OA in young and middle-aged subjects.

"That’s the wrong criterion to use," Dr. Gellhorn said, noting that mild facet joint OA is "essentially ubiquitous" by middle age. Moderate to severe facet OA, however, is more symptomatic, and predominantly affects older adults – and should be the criterion used in studies of the condition.

In a recent study of 252 patients with a mean age of 67 years who were participants in the Framingham heart study, severe OA affecting the facet joint was significantly associated with frequent low back pain (odds ratio, 2.2). Disc height narrowing was not associated with low back pain in these patients (Osteoarthritis Cartilage 2013;21:1199-206).

The findings contrast with those from prior studies, likely because the cohort was older (mean age of 67 years vs. 30s to 50s), he said.

It may be that with age, back pain classified as "nonspecific" shifts from discogenic pain in younger adults to facetogenic pain in older adults, he suggested.

Findings with respect to disc pathology and low back pain in young and middle-aged adults seem to support this hypothesis, he noted.

For example, in a study of patients with a mean age of 49 years, low back pain was associated with a twofold increased likelihood of disc height loss and annular tears, and in a study of patients aged 18-50 years, moderate disc height loss was also associated with a twofold increased likelihood of low back pain. In another study of patients with a mean age of 50 years, advanced disc height loss was associated with a threefold increased likelihood of prevalent low back pain.

In another study, severe disc height narrowing was associated with a threefold increase in the odds of low back pain in those younger than age 60 years but not in those over age 60 years.

There are markers for symptomatic facet joint OA. Despite the known association between severe facet joint OA and low back pain, "the truth is there is still limited positive predictive value for that," he said.

"Many older adults with severe facet joint OA on imaging are relatively asymptomatic," he added.

There are some additional imaging makers, however. Symptomatic facet join OA is apparent on single-photon emission computed tomography/computed tomography (SPECT/CT) or fluid-sensitive, fat-suppressed MRI. Also, 64% of patients with suspected facet joint pain in one study had bone marrow lesions on short T1 inversion recovery (STIR) MRI, which were well correlated to the side of pain, he said.

There are no serum biomarkers for the condition at present, he noted.

In addition to older age and these findings on imaging, other risk factors and correlates for facet joint OA include sex (women are 1.5-1.9 times more likely than men to have facet joint OA), race (African Americans are about 60% less likely than white Americans to have facet joint OA), and high body mass index (those with BMI of 25-30 and 30-35 have a three- and fivefold increased risk of lumbar pain associated with facet joint OA, respectively, compared with those with BMI below 25).

Abdominal aortic calcifications and more sagittal orientation of the joints (vs. coronal orientation), also are associated with facet joint OA, Dr. Gellhorn said.

With additional research, these factors could be useful for "disambiguating nonspecific low back pain," he said.

"I think we’re getting closer. We’re not there yet, but we’re getting closer," he said.

Clinically, facet joint OA often presents as localized back or neck pain at C5-C6 with some radiation into the scapular region.

"It’s less clear in the lumbar spine, but almost always people will have pain in the lumbar region, and almost always they will have pain that radiates into the buttocks," he said, noting that pain radiating into the anterior or lateral thighs can be associated with facet joint OA, but pain that extends below the knees is more likely to be radicular.

There are no specific examination maneuvers that are pathognomonic – or even particularly helpful – for the condition, he added.

It is important to keep in mind that many patients will have associated conditions, including spondylolisthesis, disc degeneration, scoliosis, muscle atrophy, and spinal stenosis.

"It’s easy to get overwhelmed in the face of this, but I would urge you not to, and to still try to disentangle some of these concepts of low back pain without throwing up your hands," he said.

Although anesthetic blockade of the medial branches of the dorsal primary ramus (or "medial branch blocks,") are considered the gold standard for diagnosis, they are controversial, have an unacceptably high rate of false-positive results with a single block, and thus may require comparative blocks, which can result in numerous spinal injections.

This is problematic; there is no good way to make the diagnosis before doing more rational, conservative treatment, he said.

"I think that there are probably better things than doing 30 injections into someone’s spine to establish a diagnosis," he said.

In fact, treatment for facet joint OA generally involves physical activity.

"You don’t want to push these people to their limits, but certainly it is important to have them move and to have them keep the strength in their spine," he said.

In the absence of good studies evaluating noninterventional therapy for confirmed facet joint pain, treatment is generally based on findings in patients with chronic nonspecific low back pain and knee OA, and there is evidence in both of those settings that suggest exercise is helpful for increasing strength and decreasing pain and disability.

A Cochrane review showed that exercise therapy provides mild to moderate benefit. Additional studies have suggested that early referral to physical therapy results in modest improvement in function at 12 months in older adults, suggesting physical therapy provides longer-term results than many other interventions for low back pain, which tend to provide only short-term relief, he noted.

Furthermore, patients who have physical therapy tend to require fewer interventions. Dr. Gellhorn found in a recent study that physical therapy in a Medicare population with low back pain was associated with fewer lumbar injections, physician office visits, and lumbar surgeries.

"So it’s very reasonable to send your patients with facet joint OA to PT," he said.

Other treatments that may have some benefit if physical activity is inadequate include intra-articular steroid injections and radiofrequency denervation.

In studies that used SPECT for inclusion criteria, intra-articular injections were better than medial branch blocks at 3 months, and were more effective at 1 month and 3 months than were injections used in studies that did not use SPECT for inclusion, he said.

Injections were not useful in studies that used physical examination or diagnostic block for inclusion.

"So if you’re basing it on metabolic activity, you’re likely to have a good outcome from your injection," he said.

Radiofrequency denervation tends to work better in the cervical spine than in the lumbar spine, but it is difficult to justify in practice because it requires medial branch block, or double or even triple block to optimize success, and because it is associated with a number of potential complications, such as loss of innervation to the multifidus muscles.

In his practice he first screens for red flags in patients who present with low back pain. Next, he gets an X-ray to look for alignment issues, and he "heavily considers – if the clinical picture fits" – whether facet joint OA might be the cause of the pain.

"I’ll talk to them about it, and then almost always, I’ll send them for an empiric trial of physical therapy plus or minus some analgesics – Tylenol or NSAIDs," he said.

If patients experience improved function and a decrease in symptoms within 6-8 weeks, he recommends that they begin a more interesting (than their home physical therapy regimen) exercise program, such as yoga or Pilates to help them maintain those gains; if they remain symptomatic, he images them.

He starts with SPECT/CT rather than MRI if facet joint OA is high on his differential list for the patient, and if that’s positive, he will consider intra-articular steroid injections. If the injections are effective he recommends yoga and/or Pilates for maintaining the gains.

In rare cases a patient doesn’t respond to the injections, and then he will consider more aggressive treatment, such as medial branch block or radiofrequency denervation.

Understanding of facet joint OA has been slow to emerge, but progress is being made, Dr. Gellhorn said.

For example, the work with SPECT/CT and STIR MRI is very exciting, he said.

"I think this is going to give us a number of things to work with: first and foremost, it’s going to give us better criteria to diagnose patients and enroll them in treatment studies," he said.

Serum, urine, and genetic biomarkers, on the other hand, are interesting and on the horizon, "but we’re not really there yet," he added.

"But I think we will be able to at least use imaging studies to monitor some response to treatment," he said.

Additional study is also needed with respect to conservative treatments. Studies comparing different exercise programs, including studies comparing strength vs. flexibility and extension vs. flexion, are needed.

Regenerative treatments, such as platelet rich plasma and autologous stem cells are another area of interest, he said.

Dr. Gellhorn reported having no disclosures.