Functional aspects of free muscle transplantation: Atrophy, reinnervation, and metabolism

The atrophy, reinnervation, and metabolism of free muscle flaps were studied in a rat model, by syngeneic and orthotopic transplantation of abdominal wall muscle flaps with neurovascular anastomoses. The three parameters were examined at different time periods, using electrophysiologic and 31-P-spectroscopic measurements. Results show that a certain degree of atrophy (one-fifth of the original volume) must be expected, even when new axons grow throughout the nerve. This is explained by the early reduction of flap metabolism, leading to a loss of parenchyma until neuromuscular conduction is restored. As the maximum duration of ischemia is 2 hr, muscular damage due to reduced metabolism was not produced.