Fully Implantable Peripheral Nerve Stimulation for Hemiplegic Shoulder Pain: A Multi-Site Case Series With Two-Year Follow-Up

Abstract

Objective: To explore the feasibility and safety of a single-lead, fully implantable peripheral nerve stimulation system for the treatment of chronic shoulder pain in stroke survivors.

Participants: Participants with moderate to severe shoulder pain not responsive to conservative therapies for six months.

Methods: During the trial phase, which included a blinded sham introductory period, a percutaneous single-lead peripheral nerve stimulation system was implanted to stimulate the axillary nerve of the affected shoulder. After a three-week successful trial, participants received an implantable pulse generator with an electrode placed to stimulate the axillary nerve of the affected shoulder. Outcomes included pain, pain interference, pain-free external rotation range of motion, quality of life, and safety. Participants were followed for 24 months.

Results: Twenty-eight participants underwent trial stimulation and five participants received an implantable pulse generator. The participants who received the implantable generator experienced an improvement in pain severity (p = 0.0002). All five participants experienced a 50% or greater pain reduction at 6 and 12 months, and four experienced at least a 50% reduction at 24 months. There was an improvement in pain interference (p < 0.0001). There was an improvement in pain-free external ROM (p = 0.003). There were no serious adverse events related to the device or to the procedure.

Conclusions: This case series demonstrates the safety and efficacy of a fully implantable axillary PNS system for chronic HSP. Participants experienced reduction in pain, reduction in pain interference, and improved pain-free external rotation ROM. There were no serious adverse events associated with the system or the procedure.

Keywords: Peripheral nerve stimulation; stroke.

Conflict of interest statement

Conflict of Interest: Statement Dr. Wilson is a consultant to SPR Therapeutics. Ms. Bennett is an employee of SPR Therapeutics. Dr. Chae is a consultant and chief medical advisor to SPR Therapeutics and owns equity in SPR Therapeutics. The remaining authors have no potential conflicts of interest to disclose.

© 2017 International Neuromodulation Society.

Figures

Figure 1

Participant flow.

Figure 2

Worst Pain in the Last 7 Days, BPI-SF3. Time T to 0 represents the trial stage, which consisted of a 3-week, blinded sham introductory period and a 3-week active stimulation period. The shaded area represents the 95% confidence intervals.

Figure 3

Patient Global Impression of Change.