Distal Nerve Transfers to the Triceps Brachii Muscle: Surgical Technique and Clinical Outcomes

PURPOSE: To report the clinical outcomes and describe the surgical technique of triceps muscle reinnervation using 2 different distal nerve transfers: the flexor carpi ulnaris (FCU) fascicle of the ulnar nerve and the posterior branch of the axillary nerve (PBAN) to the triceps nerve branch. METHODS: A retrospective review of patients undergoing FCU fascicle of ulnar nerve or PBAN to triceps nerve branch transfer was performed. Outcome measures included preoperative and postoperative modified British Medical Research Council (MRC) score, EMG results, and complications. RESULTS: Between September 2003 and April 2017, 6 patients were identified. Four patients with a traumatic upper trunk and posterior cord palsy underwent ulnar nerve fascicle to triceps nerve transfer. Two patients with a recovering upper trunk following a pan-brachial plexus palsy underwent PBAN to triceps nerve branch transfer. The median age was 30.0 years (range, 18-68 years). Surgery was performed at a median of 6.9 months (range, 5.0-8.9 months) postinjury, with a median follow-up of 18.4 months (range, 7.6-176.3) months. Before surgery, 4 patients exhibited grade M0 and 2 patients exhibited grade M1 triceps strength. Four patients had M5 donor muscle strength and 2 had grade M4. Postoperatively, 4 patients regained MRC grade M4 triceps muscle strength, 1 regained M3, and 1 regained M2. There was no noticeable donor muscle weakness. CONCLUSIONS: Nerve fascicles to the FCU and PBAN are viable options for obtaining meaningful triceps muscle recovery in a select group of patients. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.