Donor nerve selection for biceps nerve transfer in upper brachial plexus injuries with anatomical variations

BackgroundAnatomical variations in the musculocutaneous and median nerve present unique challenges for surgeons performing distal nerve transfers in cases of brachial plexus injuries, with reported rates as high as 11%. Understanding these variations is crucial, particularly when selecting the donor nerve for biceps reconstruction, a decision made even more complex in cases of upper brachial plexus injuries. We aimed to investigate the optimal donor nerve for biceps nerve transfer in patients with upper brachial plexus injuries (C5, C6, and C7) who have anatomical variations between the median and musculocutaneous nerves.MethodsA retrospective analysis was performed on 15 patients with anatomical variations between the median and musculocutaneous nerves who underwent biceps nerve transfer at a single hand surgery center. The median nerve, the junction between the median and musculocutaneous nerves, or the ulnar nerve was used as the donor nerve. Patient demographics, anatomical variations, nerve transfers, and functional outcomes were evaluated.ResultsThe mean patient age was 26 years (range, 19-35 years). The most frequent anatomical variation was a communication between the median and musculocutaneous nerves. The donor nerves were the median nerve (n = 10), the junction between the median and musculocutaneous nerves (n = 4), and the ulnar nerve (n = 1). All patients achieved good elbow flexion (M4/5), and no donor nerve deficits were observed.ConclusionsThis study suggests that the median nerve or the junction between the median and musculocutaneous nerves are viable donor options for biceps nerve transfer in patients with upper brachial plexus injuries and anatomical variations between the median and musculocutaneous nerves. These findings can help in surgical decision-making in such anatomical variations.Level of EvidenceLevel IV, Therapeutic.