Physiological and clinical advantages of median nerve fascicle transfer to the musculocutaneous nerve following brachial plexus root avulsion injury

Abstract

Loss of biceps muscle function is a significant disability after brachial plexus root avulsion injuries. Nerve grafting techniques to reestablish anatomical and functional continuity between the spinal cord and the avulsed root have not proven successful. Using nerve transfers for functional restoration of root avulsion injuries appears to be effective and has physiological advantages for reducing regeneration distances. Since the early 1990s, the Oberlin technique of transferring ulnar nerve fascicles to the motor branch of the musculocutaneous nerve has been the preferred operative technique for reinnervation and restoration of biceps muscle function. In the current study the authors examine the efficacy of an alternative technique using median nerve fascicles transferred to the musculocutaneous nerve to reinnervate the biceps muscle. Forty consecutive patients with combined C5-6 brachial plexus root avulsions were evaluated pre- and postoperatively according to the British Medical Research Council Motor Grading Scale. Personal interviews concerning quality of life (QOL) after surgery were conducted and scored based on standards set by the World Health Organization. All patients showed some degree of improvement in biceps muscle function. Thirty-six (90%) of the 40 patients regained movement against gravity. The patients had a 77% improvement in overall QOL after the surgery; most notably, 92% of the patients reported their lack of need for medication and 75% a significant lessening of postoperative pain. Redirection of part of the healthy median nerve resulted in no measurable functional deficits, and only 28 patients reported minor sensory disturbances in the first web space for an average of 3 months after surgery. Median nerve fascicle transfer resulted in a significant improvement in biceps muscle function with an acceptable level of morbidity and should be considered an effective, and in many cases preferable, alternative to ulnar nerve fascicle transfer.