Secondary Cervicothoracic Scoliosis in Congenital Muscular Torticollis

Although secondary cervicothoracic scoliosis frequently occurs in patients with congenital muscular torticollis (CMT), the relationship between scoliosis and CMT has not been evaluated. This study aims to evaluate the effects of surgical release of sternocleidomastoid (SCM) muscle on secondary cervicothoracic scoliosis in patients with CMT and determine factors affecting the improvement of scoliosis after surgical release of SCM muscle.

Eighty-seven of the 106 patients, confirmed as having secondary cervicothoracic scoliosis with CMT with a minimum 1-year follow-up, were included in this study. Preoperative and last follow-up radiologic outcomes were assessed for the cervicomandibular angle (CMA), Cobb angle of the cervicothoracic scoliosis, and direction of convexity in the scoliosis curve. Patients were divided into two groups to assess the improvement of Cobb angle according to residual growth potential; age ≤ 15 years and > 15 years. The improvement of Cobb angle after surgical release was compared in the two groups. Correlation analysis and multivariable regression analysis were performed to determine the factors affecting the improvement of scoliosis.

All the radiologic parameters, such as the Cobb angle and CMA, improved significantly after surgical release (p < 0.001). The improvement of Cobb angle was significantly higher in age ≤ 15 years than in age > 15 years (p < 0.001). The improvement of Cobb angle was significantly correlated with age (r = -0.474, p < 0.001) and the preoperative Cobb angle (r = 0.221, p = 0.036). In multivariable regression analysis, age and preoperative Cobb angle were shown to be predisposing factors affecting the improvement of scoliosis.

The results showed that SCM release can be a beneficial treatment for secondary cervicothoracic scoliosis. The improvement of scoliosis was greater when the SCM release was performed before the patient reached the end of growth.