Restoration of elbow flexion in adult traumatic brachial plexus injury – a quantitative analysis of results of single versus double nerve transfer

Background Restoration of elbow flexion is one of the key components of adult brachial plexus surgery. Nerve transfers are routinely used to attain elbow flexion. Purpose This study aims to quantify the recovery of elbow flexion power and to compare the outcome following single nerve transfer and double nerve transfer to branches of the musculocutaneous nerve in adult traumatic brachial plexus injury. Method We conducted a retrospective cohort study of patients with traumatic upper brachial plexus injury who underwent nerve transfer of the musculocutaneous nerve with either Ulnar nerve fascicles (SN) or both Ulnar and Median nerve fascicles (DN) for restoring elbow flexion. Patients with a minimum follow up of 18 months after surgery were included in this study. Elbow flexion strength was quantified using a force transducer and software module and the results were compared between the two groups. Result The median strength of elbow flexion was 14.3 Newton meter. In the SN group, the mean strength of elbow flexion was 5.4 ± 5 Nm, and for DN group it was 20.4 ± 9.9 Nm. Elbow flexion strength following DN procedure was significantly better when compared with SN. Conclusion The additional nerve transfer of median nerve fascicles with musculocutaneous nerve branch to the brachialis muscle does not add clinically obvious morbidity to the patient but has definite benefit as observed in this study. We advocate double fascicular nerve transfer for elbow flexion in upper brachial plexus injuries if the median and ulnar nerve functions are normal.