Poster 149: Use of nerve-muscle grafts to improve the control of a myoelectric shoulder disarticulation prosthesis: a case report.

Abstract

Objective: To develop additional electromyographic control signals in a shoulder disarticulation amputee. Design: Single case study. Setting: Academic acute hospital and rehabilitation hospital. Participant: Patient with bilateral shoulder disarticulation amputation. Interventions: During revision surgery, the patient’s 4 major brachial plexus nerves were surgically grafted to 3 different areas of his pectoralis major muscle and the pectoralis minor (which was moved to the lateral chest wall). After reinnervation occurred a myoelectric prosthesis that used these electromyographic control sites was fit on the patient. Main Outcome Measures: Number of independent electromyographic control sites obtained and prosthetic function. Results: After reinnervation occurred, 4 separate electromyographic sites could be identified and 3 were usable for the control of the prosthesis. The musculocutaneous nerve-muscle graft was used to control elbow flexion. 2 independent sites were recordable from the median nerve-muscle graft and were used to control terminal device opening and closing. A radial nerve-muscle graft had a recordable signal, but it was small, had large electromyographic interference, and was difficult to use for controlling a prosthesis. The ulnar nerve to pectoralis muscle graft was nonviable. The patient was able to operate his terminal device, elbow, and, with cocontraction switching, a powered wrist. He reported that the control was much easier and better than with his previous externally powered prosthesis, which used shoulder touch-pad control. Conclusion: Nerve-muscle grafts can be used to develop additional myoelectric control signals for improved prosthesis control in high level upper-limb amputees.