Pharmacotherapy is best used as an adjunct to other treatments.2 Although PLP is typically treated as neuropathic pain, only a few medications have been critically evaluated for treating it.6 Morphine (number needed to treat [NNT]=2.5; 95% confidence interval [CI], 1.9-3.4) and other opioids, including tramadol (NNT=3.9; 95% CI, 2.7-6.7 in neuropathic pain) help some patients.6,7 Despite the proven benefit of tricyclic antidepressants (TCAs) in other neuropathic pain conditions, a recent RCT demonstrated no benefit of TCAs over placebo in PLP.8 Anticonvulsants, including gabapentin, have documented benefit in neuropathic pain modalities and are often used for PLP.6 However, their value in reducing PLP is still under investigation.6 One 2002 RCT showed benefit regarding an improvement of the visual analog scale by an average of 3 points (on a 10-point scale) after 6 weeks of gabapentin therapy.9 A similarly designed 2006 RCT of gabapentin, however did not identify significant pain reductions.10
Promising adjuvant therapies use mirroring techniques
Of the adjuvant treatments mentioned previously, only mirror box therapy has shown promise. This technique allows the amputee to perceive the missing limb by focusing on the reflection of the remaining limb during specific movements and activities. Theoretically, this perception allows reconfiguration of the amputee’s sensory cortex.
Virtual reality therapy employs similar techniques based on the idea that the brain can be deceived. Initial case studies are promising and have prompted further research.11
Recommendations
The US Department of Veterans Affairs and Department of Defense recently issued clinical guidelines for rehabilitating lower-limb amputees that include a segment on pain management.12 The guidelines stress the importance of an interdisciplinary team approach that addresses each pathology plaguing the amputee.
They recommend narcotics during the immediate postoperative period, followed by transition to a non-narcotic medical regimen during the rehabilitation process. The guidelines don’t support a single, specific pain control method over others; they recommend the following approaches to PLP:
- pharmacologic treatment, which may include antiseizure medications, tricyclic antidepressants, selective serotonin reuptake inhibitors, NSAIDs, dextromethorathane, or long-acting narcotics
- epidural analgesia, patient-controlled analgesia, or regional analgesia
- nonpharmacologic therapies, including TENS, desensitization, scar mobilization, relaxation, and biofeedback.
Acknowledgements
The opinions and assertions contained herein are the private views of the authors and not to be construed as official, or as reflecting the views of the US Air Force Medical Service or the US Air Force at large.