Surgical Peripheral Nerve Decompression for the Treatment of Painful Diabetic Neuropathy of the Foot- A Level 1 Pragmatic Randomized Controlled Trial

SLR - September 2019 - Charlene M. Dennemeyer

Reference: Best T.J., Best C.A., Best A.A., Fera L.A. Surgical Peripheral Nerve Decompression for the Treatment of Painful Diabetic Neuropathy of the Foot – A Level 1 Pragmatic Randomized Controlled Trial. Diabetes Res Clin Pract. 2019 Jan;147:149-156.

Scientific Literature Review

Reviewed By: Charlene M. Dennemeyer, DPM 
Residency Program: North Colorado Medical Center – Greeley, CO

Podiatric Relevance: Diabetic peripheral sensorimotor polyneuropathy (DPN) is a challenging and common condition leading to persistent pain and decreased tactile sensation. There is nearly 50 percent incidence of DPN in individuals diagnosed with diabetes mellitus, and they typically seek treatment due to the significant impact on activities of daily living and quality of life. A multitude of remedies can be employed such as topical treatments, oral medications including anticonvulsants and antidepressants, TENS, and spinal cord stimulation. The purpose of this study was to determine whether nerve decompression surgery is effective in the treatment of painful DPN in the lower extremities.
 

Methods: This is a single-blinded RCT including patients ≥18 years of age with DM type 1 or 2, HbA1c <8.0 percent, and with DPN. Peripheral nerve involvement was determined clinically and with nerve conduction studies (NCS). Twenty-one patients were randomized and analyzed. The intervention group underwent decompression of common peroneal, tibial, and deep peroneal nerves. The control group continued their usual treatment regimen. Follow up was at three, six, and 12 months. Average daily pain was measured on the 10-point McGill Pain Questionnaire VAS and the NeuroQoL scale. At baseline and 12 months, patients were assessed with the Total Neuropathy Score (TNS). The investigators were blinded to group allocations while gathering data. Primary outcomes were improvement in pain scores at 12 months compared to baseline and quality of life. Secondary outcomes included improvement in TNS score, tactile sensibility, and change in nerve conduction studies.

Results:
  • Intervention group had a longer duration of diabetes, worse glycemic control, were more likely taking oral antihyperglycemics and neuropathic pain agent
  • No significant difference between McGill pain VAS between 12 months and baseline, however pain scores changed over time and pain reduction after surgery was greatest at three to six months
  • NeuroQol demonstrated statistically significant changes of more than three points in pain scores at 12 months
  • No significant difference between groups for secondary outcomes
  • Intervention group was less likely to have poor nerve conduction studies after surgery compared to control
  • Intervention group participants had over three times the odds of rating their overall pain as “better” as opposed to “worse” or “unchanged” compared to the control group
Conclusions: Over the more recent years, the idea of surgically decompressing peripheral nerves has gained popularity and was originally performed primarily in the upper extremities. The theory behind the procedure is that there is focal physical entrapment of the nerve secondary to the systemic disease, as opposed to true axonal damage itself. This study demonstrated that the method of surgical decompression in the lower extremities is a promising method of treatment for superimposed nerve compressions and alleviating pain in DPN. There have been previous studies on this subject, however strong evidence has been lacking due to methodologic concerns. This study did reveal significant pain reduction within the three- to six-month period following surgery, however no long term relief was demonstrated. Further studies with a large sample size and incorporation of measures to assess change in sensation and reduction in ulcers and amputation may reveal more compelling results.