Principles of Free Neurovascular Muscle Transplantation
If no intact muscle is available for transfer, but a nerve is, the functional transplantation of a muscle must be discussed. This procedure has to be considered especially after ischemic or fibrotic changes of muscles, for example, in Volkmann’s contracture. If no muscle is available to reconstruct flexion of wrist and hand, a muscle such as a gracilis muscle, can be harvested with its neurovascular bundle (►Fig. 12.1). The vessels are anastomosed to radial vessels at the level of the proximal forearm. The branch of the obturator nerve, which usually supplies the gracilis muscle, is then sutured to the interosseous anterior nerve (which contains only motor fibers), and the muscle is then inserted with the correct tension into the defect. Tension during recovery is avoided, and after approximately 3 months (depending on the length of nerve distal to suture) reinnervation can be detected, and physiotherapy can start. A secondary tightening of the muscle might become necessary. It was shown that the physiological structure of the muscle follows the nerve according to the fiber type. Although after reinnervation the number of motor units is decreased and their size are increased (both up to 50%), strength, however, is sufficient for regular movements, and can be trained postoperatively.
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