Reusing Motor Branches of the Neurotized Median Nerve for Functioning Free Muscle Transplantation to Augment Finger Flexion in Total Brachial Plexus Palsy

In total brachial plexus injury (BPI), there are inadequate donor nerves to adequately reinnervate the limb to regain full upper limb function. Free vascularized ulnar nerve grafts have been used to connect root stumps to the distal median nerve (MN) for hand neurotization. Axonal regeneration arrives by presenting with a sensate hand, but unpredictable motor reinnervation of the target muscles renders a paralyzed hand without extrinsic finger flexion. Thus, we describe the strategy of recycling the motor branches from the MN and replacing the forearm muscles with free functioning muscle transplantations (FFMTs). Between 1998 and 2017, a total of 34 patients received gracilis-FFMT for finger flexion, using previously reinnervated MN motor branches as the motor neurotizer. The muscle power of finger flexion [Medical Research Council (MRC)] and the satisfactory rate (≥M2) were recorded. The patient-reported outcomes, including the shortened version of the Disability of Arm, Shoulder and Hand (QuickDASH) and the Michigan Hand Outcomes Questionnaire (MHQ), were obtained. About 67.7% of the patients achieved finger flexion of M2 or greater after FFMT. The average postoperative QuickDASH score significantly decreased from 76.3 ± 13.8 to 65 ± 15.8 (p = 0.042). The overall MHQ score showed significant improvement in the domains of overall hand function and work. FFMT neurotized by previously reinnervated MN branches can serve as a salvage or adjunctive strategy to augment finger flexion. The surgical strategy of recycling previously innervated MN to an FFMT helps with efficient planning of donor nerves in reconstruction for total BPI.