Outcome Analysis of Medial Triceps Motor Nerve Transfer to Axillary Nerve in Isolated and Brachial Plexus-Associated Axillary Nerve Palsy

Background: Since 2007, the authors have performed the triceps-to-axillary nerve transfer using the medial triceps branch to reconstruct axillary nerve function in brachial plexus and isolated axillary nerve palsies. Methods: A retrospective chart review was undertaken of patients reconstructed with this transfer, recording patient and injury demographics and time to surgery. Preoperative and postoperative function was graded using the Medical Research Council scale and the Disabilities of the Arm, Shoulder, and Hand questionnaire. Results: Postoperatively, 31 patients (64.6 percent) reached Medical Research Council grade 3 or higher at final follow-up. The median Disabilities of the Arm, Shoulder, and Hand score was 59.9 (interquartile range, 38.8 to 70.5) preoperatively and 25.0 (interquartile range, 11.3 to 61.4) at final follow-up. Sixteen patients (33 percent) had isolated axillary nerve injury; the median Medical Research Council grade was 4.25 (interquartile range, 3 to 4.25), with 14 patients (87.6 percent) achieving grade 3 or higher. Thirty-two patients (77 percent) had brachial plexus-associated injury; median Medical Research Council grade was 3 (interquartile range, 2 to 3), with 17 patients (53.1 percent) achieving grade 3 or higher. Conclusion: Medial triceps nerve branch is a strong donor for triceps-to-axillary nerve transfer; however, injury factors may limit the motor recovery in this complex patient population, particularly in axillary nerve palsy associated with brachial plexus injury. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.