Introduction Peripheral nerve stimulation (PNS) has historically been used to treat chronic pain, but generally requires implantation of a permanent system for sustained relief. A recent study found that a 60-day PNS treatment decreases post-amputation pain, and the current work investigates longer-term outcomes out to 12 months in the same cohort.
Methods As previously reported, 28 traumatic lower extremity amputees with residual and/or phantom limb pain were randomized to receive 8 weeks of PNS (group 1) or 4 weeks of placebo followed by a crossover 4 weeks of PNS (group 2). Percutaneous leads were implanted under ultrasound guidance targeting the femoral and sciatic nerves. During follow-up, changes in average pain and pain interference were assessed using the Brief Pain Inventory–Short Form and comparing with baseline.
Results Significantly more participants in group 1 reported ≥50% reductions in average weekly pain at 12 months (67%, 6/9) compared with group 2 at the end of the placebo period (0%, 0/14, p=0.001). Similarly, 56% (5/9) of participants in group 1 reported ≥50% reductions in pain interference at 12 months, compared with 2/13 (15%, p=0.074) in group 2 at crossover. Reductions in depression were also statistically significantly greater at 12 months in group 1 compared with group 2 at crossover.
Conclusions This work suggests that percutaneous PNS delivered over a 60-day period may provide significant carry-over effects including pain relief, potentially avoiding the need for a permanently implanted system while enabling improved function in patients with chronic pain.
Trial registration number NCT01996254.
- peripheral nerve stimulation
- neuropathic pain
- phantom pain
- post-amputation pain
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Contributors CG, RR, SPC, NDC, and JB contributed to design of the study. CG, BMI, JR, SL, MJD, CH, AN, and JM collected data. CG, BMI, JR, SL, MJD, CH, RR, AN, JM, SPC, NDC, and JB contributed to drafting and revision of the manuscript.
Funding The study was funded by the Department of Defense (CDMRP PRORP W81XWH-12-2- 0132) and SPR Therapeutics.
Competing interests CG, JR, MJD, and RR have consulted for SPR Therapeutics. The institutions of CG, BMI, SL, MJD, JM, and RR have received funding from SPR Therapeutics for other clinical studies. NDC and JB are employees of SPR Therapeutics.
Patient consent for publication Obtained.
Ethics approval The study was conducted in accordance with relevant sections of the U.S. Code of Federal Regulations, the Declaration of Helsinki, and International Conference on Harmonization guidelines for good clinical practice. The institutional review boards for each site and the U.S. Army Medical Research and Materiel Command Human Research Protection Office approved the study protocol and informed consent.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement The data will be available in a public repository (CLinical Trials.gov) by January 2020, per the required posting timelines by FDA.
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