Comparison of single versus double nerve transfers for elbow flexion after brachial plexus injury

Background: Restoration of elbow flexion is commonly achieved with nerve transfer to the musculocutaneous nerve branches after upper trunk brachial plexus injury. It is unknown if double nerve transfer to the biceps and brachialis nerve branches results in greater strength than single nerve transfer to the biceps branch alone. Methods: A retrospective review was performed of all patients receiving nerve transfer to restore elbow flexion. Single and double nerve transfers were compared in regard to severity of injury, elbow flexion, supination, grip strengths, and Disabilities of the Arm, Shoulder, and Hand scores. Elbow flexion and supination torque strength were measured quantitatively. Results: Fifty-five patients underwent nerve transfer to restore elbow flexion (23 single, 32 double). At similar follow-up periods, British Medical Research Council grade improved to 4 or better in 14 of 21 single and 24 of 30 double nerve transfer patients. Supination strength was similar between groups (p = 0.148). Grip strength was greater in the double nerve transfer patients (p = 0.028). Preoperative Disabilities of the Arm, Shoulder, and Hand scores were significantly greater in single versus double nerve transfer patients (p = 0.018). Although single nerve transfer patients had a greater improvement in scores, the final mean scores were similar in the two groups. The severity of injury was different between the two groups, with 19 of 23 single nerve transfer patients having injury beyond the C5-6 level and only 16 of 32 of double nerve transfer patients with greater than C5-6 injury (p = 0.020). Conclusions: Outcomes are similar between the two groups for elbow flexion and supination strength. Postoperative Disabilities of the Arm, Shoulder, and Hand scores are similar in single and double nerve transfer patients.