Free Vascularized Ulnar Nerve Flap in Total Brachial Plexus Injury-The Chang Gung Experience

In total brachial plexus injuries, the demand to restore multiple functions of the injured limb is restrained by the limited number of donor nerves for neurotization. The restoration of hand function is often considered the holy grail in total brachial plexus reconstruction. The strategy to use the free vascularized ulnar nerve flap (VUNF) to reestablish both motor function and finger-like sensation in the hand as a one-stage procedure is preferred. The strategy requires harvest of the ulnar nerve as a free flap, microsurgical anastomosis of the perfusing vessels, and coaptation of the ulnar nerve graft to the proximal available donor nerves (ipsilateral C5 or contralateral C7) and distal selected targeted nerve. This chapter is focused on (1) the physiology behind the vascularized nerve, (2) the history of the vascularized nerve, and (3) the application of the VUN as a free flap (VUNF) in total brachial plexus palsy.