BACKGROUND AND OBJECTIVES: Chronic neuropathic pain is a common challenging condition following amputation. Recent research demonstrated the feasibility of percutaneously implanting fine-wire coiled peripheral nerve stimulation (PNS) leads in proximity to the sciatic and femoral nerves for postamputation pain. A multicenter, double-blinded, randomized, placebo-controlled study collected data on the safety and effectiveness of percutaneous PNS for chronic neuropathic pain following amputation.
METHODS: Twenty-eight lower extremity amputees with postamputation pain were enrolled. Subjects underwent ultrasound-guided implantation of percutaneous PNS leads and were randomized to receive PNS or placebo for 4 weeks. The placebo group then crossed over and all subjects received PNS for four additional weeks. The primary efficacy endpoint evaluated the proportion of subjects reporting =50% pain reduction during weeks 1-4.
RESULTS: A significantly greater proportion of subjects receiving PNS (n=7/12, 58%, p=0.037) demonstrated =50% reductions in average postamputation pain during weeks 1-4 compared with subjects receiving placebo (n=2/14, 14%). Two subjects were excluded from efficacy analysis due to eligibility changes. Significantly greater proportions of PNS subjects also reported =50% reductions in pain (n=8/12, 67%, p=0.014) and pain interference (n=8/10, 80%, p=0.003) after 8 weeks of therapy compared with subjects receiving placebo (pain: n=2/14, 14%; pain interference: n=2/13, 15%). Prospective follow-up is ongoing; four of five PNS subjects who have completed 12-month follow-up to date reported =50% pain relief.
CONCLUSIONS: This work demonstrates that percutaneous PNS therapy may provide enduring clinically significant pain relief and improve disability in patients with chronic neuropathic postamputation pain.
TRIAL REGISTRATION NUMBER: NCT01996254.
There are statistically significant results in this very small study. Reproduction is key. Likely this will be commercially available soon, similar to the vagal nerve stimulators being marketed widely, these days.