An evaluation of muscle pathology in idiopathic scoliosis.

This study assessed the degree of longissimus muscle pathology in 15 patients with idiopathic scoliosis. Bilateral muscle biopsy specimens were taken at the apex of the scoliotic curve and from five control subjects and processed histochemically. All biopsy specimens were free of muscle pathology. However, patients had a higher proportion of Type I fibers on the convex than the concave side of the curve (70.2 vs. 59.5%), whereas the controls had no difference. Fiber type imbalance in patients with idiopathic scoliosis is thought to result from compensatory stretching of muscle and not to be the cause of the deformity.