Abstract
Introduction
Several studies have presented morphological, biochemical, and histopathological changes in the paraspinal skeletal muscle of patients with adolescent idiopathic scoliosis (AIS). Some abnormalities, such as an increased amount of type I fibers in the concavity and the decreased number of type II in the convexity, an increase in the intracellular concentration of glycogen and lipids, structural changes in the sarcolemma and myotendinous junction, changes in the activity muscle enzyme, and an increase in intracellular calcium concentration, have been demonstrated. The aim of this article is to evaluate the rotator muscle fibers at the apical vertebra of curves of patients with AIS by histological and immunohistochemical analysis.
Materials and Methods
Twenty-one patients with AIS submitted to surgical correction between 2010 and 2013 had the spinal rotator muscles biopsied in the concavity and convexity of the apical vertebra of the thoracic curve during the surgery. Serial cryosections were stained with hematoxylin and eosin (HE), Sudan Red, NADH, ATPase, and Cytochrome oxidase. We evaluated muscle atrophy and hypertrophy, fatty proliferation, presence of endomysial and perimysial fibrosis, presence of hyaline fibers, mitochondrial proliferation, muscle necrosis, nuclear centralization, and inflammation. Two independent observers evaluated the sections.
Results
The average value of the angle of the main thoracic curve was 68 degrees Cobb. For analysis of nonparametric paired variables between the concave and convex sides, McNemar test was used with a significance level of 5%. The results of relative frequency and “p” values showed significant differences in both endomysial and perimysial fibrosis and fatty involution when compared with both sides of the apical vertebra.
Conclusion
The paraspinal muscles at the apex of the deformity had a higher involvement in the concavity when analyzing the fatty involution and fibrosis. However, both sides showed signs of myopathy, muscle atrophy through areas of necrosis, presence of hyaline fibers, and mitochondrial proliferation.