Electrical Stimulation for Treating Chronic Poststroke Shoulder Pain Using a Fully Implanted Microstimulator with Internal Battery

Abstract

This case report describes the first stroke survivor with chronic poststroke shoulder pain treated with electrical stimulation delivered via a fully implanted microstimulator containing a rechargeable internal battery. In light of existing efficacy data for similar types of treatment, the investigational system described in this report was developed to address the limitations of previously evaluated electrical stimulation devices. A 58-yr-old male stroke survivor with chronic hemiparesis and chronic shoulder pain received up to 6 hrs of stimulation daily over 12 wks. The microstimulator was implanted percutaneously near the axillary nerve at the quadrilateral space, under local anesthesia during an outpatient procedure. The implantation procedure was well tolerated. There were no adverse events related to the implantation procedure or treatment (implanted peripheral nerve stimulation). Outcomes were obtained before treatment, after 12 wks of treatment, and at 3-mo follow-up. Question no. 12 of the Brief Pain Inventory was used as the primary outcome measure to evaluate response to treatment. Shoulder pain decreased from 8/10 before treatment to 4/10 after treatment and decreased further to 3/10 at 3-mo follow-up. Passive range of motion and motor function also improved after treatment. Sensation, shoulder subluxation, activities, and quality-of-life did not change. The feasibility, safety, and efficacy of implanted peripheral nerve stimulation to treat poststroke shoulder pain should be evaluated further in clinical trials already underway.