Pathologic Study of Paraspinal Muscles in Different Types of Scoliosis

Scoliosis may be due to neuromuscular or congenital diseases or occur in idiopathic forms. Today, disorders of the paraspinal muscles are viewed as a possible cause of scoliosis. Idiopathic scoliosis is considered as the consequence of primary connective tissue disorders by some researchers; others maintain that muscle deformities are secondary to compensation of the physical deformity and/or treatment of the patients. This study was performed to determine the primary or secondary nature of paraspinal muscle disorders in scoliosis.In this cross-sectional study, all patients with scoliosis undergone surgery two hospitals in Tehran, from November 2006 to June 2007, were included. To determine the degree of muscle atrophy, paraspinal muscle biopsies were obtained during the operation from the curvature at apex, on both concave and convex sides. In this study atrophy defined as pathology report of any degree of atrophy in any side. Other data including the degree of deformity according to the Cobb's angle, the use of brace and duration of its use were collected.19 (59.4%) and 13 (40.6%) of 32 patients displayed some degrees, and no prominent signs of atrophy, respectively. All the patients with neuromuscular, 43.8% of Idiopathic and 33.4% of congenital scoliosis displayed signs of atrophy. Atrophy percentage in neuromuscular was significantly different comparing two others. Mean deformity in the atrophy and normal groups was 97.82 ± 21.09 and 68.80 ± 25.91 degrees, respectively, with a significant difference between the two groups (p < 0.05).It seems that the atrophy in idiopathic and congenital scoliosis is much lower than neuromuscular. We conclude that idiopathic scoliosis is not due to primary disorders of the paraspinal muscles and other factors such as vestibular disorders, melatonin secretion, platelet microstructure, and other postural control disorders are likely involved in its etiology. Further, the multifactorial nature of scoliosis should not be overlooked.