Modified contralateral C7 transfer to restore ulnar nerve function without sacrificing median nerve recovery: an experimental study.

Contralateral C7 (cC7) transfer is a technique used in patients with total brachial plexus avulsion. An ulnar nerve graft (UNG) is usually used, as intrinsic function is not expected to be restored due to length of reinnervation required. In this study, we attempted to improve intrinsic function recovery by preserving the deep branch of the ulnar nerve (dbUN) and reanimating it with the anterior interosseous nerve (AIN) after cC7 transfer. Fifty-four rats were divided into the following three groups: Group A, traditional cC7 transfer to the median nerve with a UNG; Group B, cC7 transfer preserving and repairing the dbUN with the terminal branch of the AIN; Group C, same as Group B; however, the dbUN was coapted after 1 month with the AIN. At 3, 6 and 9 months postoperatively, the results of electrodiagnostic and histomorphometric examinations of the interosseous muscle were significantly better in Groups B and C, without affecting AIN recovery. In conclusion, the modified cC7 transfer technique can potentially improve intrinsic function recovery without affecting median nerve recovery.