External neurolysis may result in early return of function in some muscle groups following brachial plexus surgery.

A retrospective chart review, of those individuals seen and operated on by the Multidisciplinary Brachial Plexus Clinic team at the University of Kentucky Chandler Medical Center, was undertaken to determine those individuals who had early return-of-function following surgery for BPI. Seven patients met our criteria, with four of them having substantial improvement of two or more points gained on the MRC rating scale, in one or more muscle groups within six to eight weeks after surgery. Those patients with return-of-function earlier than expected for axonal regrowth from nerve transfer or grafting, had evidence for continuity but no significant reinnervation before surgery in the muscle groups that improved. We theorize that this early improvement is related to a compression-induced dysfunction which inhibited reinnervation and was relieved by performing external neurolysis.