The possibility and potential feasibility of putting an extra functioning free muscle transplant onto a normal limb: Experimental rat study

BACKGROUND: Functioning free muscle transplantation is currently and popularly used clinically to restore motor deficit caused by traumatic muscle loss or chronic muscle denervation. However, no one uses functioning free muscle transplantation in a normal subject who has no motor deficit. This study was designed to investigate the possible and potential feasibility of transferring an extra free muscle transplant onto a normal limb. METHODS: A chimeric flap including biceps muscle with its neurovascular pedicles and a skin perforator flap was designed, harvested, and transferred from a Lewis inbred rat to the other rat overlying the original biceps following neurovascular repair where the ulnar nerve was chosen as the neurotizer. Sixteen rats were operated on and evaluated 6 months after surgery. Outcome measurements included arm circumferences, electrophysiologic studies, elbow flexion force, and muscle mass. The contralateral normal biceps was used as the control. RESULTS: All outcome measurements revealed that the extra muscle transfer resulted in significant increases in size and function of the operative limb without interfering with the original biceps function. CONCLUSION: The authors' study demonstrates the possible and potential application of using extra free muscle transplantation for functional and aesthetic augmentation purposes in a normal subject.