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

To 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. The benefits of nerve decompression remain inconclusive. This double-blinded, observation and same-patient sham surgery-controlled randomized trial enrolled patients aged 18 to 80 years with lower extremity painful DPN who failed 1 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 the 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 the 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=m 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). The 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 as a placebo effect may be responsible for part or all of these effects.