Phrenic Nerve Transfer for Elbow Flexion and Intercostal Nerve Transfer for Elbow Extension

Purpose To explore long-term recovery of elbow flexion and extension after transferring the phrenic nerve and intercostal nerves, respectively, in adults with global brachial plexus avulsion injuries. Methods Seven adults with global brachial plexus avulsion injuries had the phrenic nerve transferred to the musculocutaneous nerve (or to the anterior division of upper trunk) and intercostal nerves transferred to the triceps branch of the radial nerve at our hospital 7 to 12 years ago. The results of elbow motor strength testing using the Medical Research Council grading scale, and electrodiagnostic findings using electromyogram examinations, were studied retrospectively. Pulmonary function tests were also performed at final visits. Results Functional elbow flexion was obtained in most of the 7 cases (M2, 1; M3, 3; M4, 2; and M5, 1) but elbow extension was absent or insufficient in all subjects (M0, 1; M1, 3; and M2, 3). Electrical results showed successful biceps reinnervation in 6 patients and successful triceps reinnervation in 5. No patient experienced breathing problems, and pulmonary function results were within normal range. Conclusions In the long term, after brachial plexus avulsion injury in most patients who underwent both phrenic nerve and intercostal nerve transfer to achieve elbow flexion and extension eventually obtained satisfactory elbow flexion but poor elbow extension. We recommend against transferring the intercostal nerves to the triceps branch of radial nerve in conjunction with primary phrenic to musculocutaneous nerve transfer. Type of study/level of evidence Therapeutic IV.