Effect of Lower Extremity Nerve Decompression in Patients with Painful Diabetic Peripheral Neuropathy

Objective: Evaluate the effect of nerve decompression on pain in patients with lower extremity painful Diabetic Peripheral Neuropathy (DPN). Summary Background Data: Currently, no treatment provides lasting relief for patients with DPN. Benefits of nerve decompression remain inconclusive. Methods: This double-blinded, observation- and same-patient sham surgery-controlled randomized trial enrolled patients aged 18-80 years with lower extremity painful DPN who failed one-year of medical treatment. Patients were randomized to nerve decompression- or observation-group (2:1). Decompression-group patients were further randomized and blinded to nerve decompression in either right or left leg and sham surgery in the opposite leg. Pain (11-point Likert score) was compared between decompression and observation groups and between decompressed versus sham legs at 12 and 56 months. Results: Of 2987 screened patients, 78 were randomized. At 12 months, compared with controls (n=37), both right-decompression-group (n=22) and left-decompression-group (n=18) reported lower pain (mean difference for both, −4.46; 95% CI, −6.34 to −2.58 and −6.48 to −2.45 respectively; P <0.0001). Decompressed and sham legs equally improved. At 56 months, compared with controls (n=14), pain was lower in both the right-decompression-group (n=20) (mean difference, −7.65; 95% CI, −9.87 to −5.44; P <0.0001) and left-decompression-group (n=16) (mean difference, −7.26; 95% CI, −9.60 to −4.91; P <0.0001). Mean pain score was lower in decompressed versus sham legs (mean difference, 1.57 95% CI, 0.46 to 2.67; P =0.0002). Conclusion: Although nerve decompression was associated with reduced pain, the benefit of surgical decompression needs further investigation since a placebo effect may be responsible for part or all of these effects.