[Changes in muscle of a muscle flap after severance of its innervating nerve. A preliminary study]

The purpose of this study is to observe changes in muscle after severance of its main innervation, especially the changes in its volume and weight. In ten rabbits, it was found that the reduction of the volume of gastrocnemius muscle flap was 47.8%, and that of gastrocnemius and soleus muscles was 50.5% one month after the severance of the tibial nerve, while their weights were decreased 47.6%, 51.3% and 46.9% respectively. After three months the respective reduction in volume was 40.3%, 32.3% and 38.8%, while the weight was reduced to 44.0%, 34.0 and 40.3%, respectively. Histological examination revealed capillary dilatation and congestion, decrease myofibrils and increase of adipose tissue. Evidence of diminution of muscular metabolism and energy consumption was found by histochemical study, including ATPase, phosphorylase, and succinic dehydrogenase staining. The result of electromyogram examination confirms the presence of muscle denervation.