Contralateral C7 nerve transfer with direct coaptation to restore lower trunk function after traumatic brachial plexus avulsion

Abstract

Background: Contralateral C7 nerve transfer to the median nerve has been used in an attempt to restore finger flexion in patients with total brachial plexus avulsion injury. However, the results have not been satisfactory mainly because of the requirement to use a long bridging nerve graft, which causes an extended nerve regeneration process and irreversible muscle atrophy. A new procedure involving contralateral C7 nerve transfer via a modified prespinal route and direct coaptation with the injured lower trunk is presented here.

Methods: Contralateral C7 nerve transfer via the modified prespinal route and direct coaptation with the injured lower trunk was performed in seventy-five patients with total brachial plexus avulsion injury. Thirty-five required humeral shortening osteotomy (3 to 4.5 cm) in order to accomplish the direct coaptation. The contralateral C7 nerve was also transferred to the musculocutaneous nerve through the bridging medial antebrachial cutaneous nerve arising from the lower trunk in forty-seven of the seventy-five patients. Recovery of finger, wrist, and elbow flexion was evaluated with use of the modified British Medical Research Council muscle grading system.

Results: The mean follow-up period (and standard deviation) was 57 ± 6 months (range, forty-eight to seventy-eight months). Motor function with a grade of M3+ or greater was attained in 60% of the patients for elbow flexion, 64% of the patients for finger flexion, 53% of the patients for thumb flexion, and 72% of the patients for wrist flexion.

Conclusions: Contralateral C7 nerve transfer via a modified prespinal route and direct coaptation with the injured lower trunk decreases the distance for nerve regeneration in patients with total brachial plexus avulsion injury. There was satisfactory recovery of finger flexion and wrist flexion in this series. In addition, contralateral C7 nerve transfer was successfully used to repair two different target nerves: the lower trunk and the musculocutaneous nerve.