Introduction Early heterotophic nerve repair has been utilized as a “baby-sitter” to protect facial musculature from denervation atrophy. This technique optimizes eventual spontaneous mimetic function created by cross facial nerve regeneration. Experimental studies have shown that early motor nerve repair to a recipient muscle can have a protective influence on the motor nerve by promoting axon regeneration and neuron survival. The author describes early neuro-muscular transplantation used to optimize the motor nerve in preparation for FMMT, a reverse of the standard “baby-sitter” technique.

Case Report A 37-year-old man sustained a crush-avulsion of his forearm resulting in an 18x22cm soft-tissue defect involving the dorsal and volar compartments as well as the radial nerve proximal to its sensory branch. The patient underwent latissimus muscle transplantation to obtain primary wound cover. The thoracodorsal nerve measuring 10cm was repaired to the mixed motor-sensory radial nerve, which was debrided 2cm proximal to healthy appearing fascicles outside the zone of injury.

Between the 6th and 8th weeks after muscle transplantation, the latissimus began to contract. By the 13th week, the patient could contract the entire muscle.

Eight months after latissimus transplantation, the contra-lateral gracilis was harvested to restore finger and wrist extension. During elevation of the latissimus muscle, an avascular septo-alveolar plane similar to that between two healthy muscle bellies was developed with gentle finger dissection. After the muscle was inset and revascularized, the thoracodorsal nerve was transected and repaired to the obturator nerve’s insertion into the gracilis muscle.

At seven weeks after FMMT, there was palpable contraction. At eight weeks the patient had regained active wrist and finger extension. At seven months he had regained 92% of wrist extension compared to his uninjured hand. Strength was 4+ based on the Medical Research Council scale.

Conclusion The simple technique of innervating the muscle used for coverage of a large upper extremity wound helped optimize the motor nerve and wound bed. Latissimus excursion signaled the appropriateness of the target motor nerve and eventually created a recipient-bed comparable to the plane between two healthy muscles. The thoracodorsal nerve provided enough graft length to both allow initial proximal repair outside the zone-of-injury and eventual distal repair as close as possible to the functional muscle, decreasing reinnervation-time. The theoretic benefits of early nerve repair and restoration of neurotrophic influences on nerve regeneration, neuron survival, and ultimatley function of the FMMT will be discussed.