Selective Neurotization of the Radial Nerve in the Axilla Using a Full-Length Phrenic Nerve to Treat Complete Brachial Plexus Palsy: An Anatomic Study and Case Report

BACKGROUND: Current methods for the restoration of wrist and digit extension after a complete brachial plexus injury result in poor outcomes. OBJECTIVE: To determine the internal topography of the radial nerve in the axilla and present a method for selective neurotization of the radial nerve using a full-length phrenic nerve. METHODS: Internal topographic features of the fascicular groups of the radial nerve were observed at the level of latissimus dorsi insertion in 16 cadavers. Selective neurotization of the medial portion of the antebrachial part of the main trunk of the radial nerve was performed at this level using a full-length phrenic nerve in one patient with complete brachial plexus palsy. RESULTS: At the level of latissimus dorsi insertion in the axilla, the antebrachial part of the radial nerve, which innervates the forearm extensors, is located at the superior lateral part of the radial nerve trunk. It can be divided into medial and lateral portions. Transfer of a full-length phrenic nerve was used to selectively reinnervate the medial portion of the antebrachial part of the radial nerve in 1 patient with complete brachial plexus palsy. The patient's antebrachial extensor muscles regained Grade 4 power when assessed 3 years after surgery. CONCLUSION: The fibers that innervate the antebrachial extensors are located at the superior lateral part of the radial nerve trunk in the axilla. Selective neurotization of the radial nerve at this level with a phrenic nerve was performed successfully in 1 patient.