Effect of Lower Extremity Nerve Decompression in Patients with Painful Diabetic Peripheral Neuropathy: The DNND Randomized, Observation Group- and Placebo Surgery-controlled Clinical Trial.

Abstract

Evaluate the effect of nerve decompression on pain in patients with lower extremity painful Diabetic Peripheral Neuropathy (DPN). Currently, no treatment provides lasting relief for patients with DPN. Benefits of nerve decompression remain inconclusive. 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. 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). 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.