Asymmetric biomechanical characteristics of the paravertebral muscle in adolescent idiopathic scoliosis

Background We sought to assess the biomechanical properties of the paravertebral muscles in adolescent idiopathic scoliosis patients with Lenke Type 1, 2, or 3 (Lenke 1-3) curves. Methods The MyotonPro® and shear wave elasticity imaging system were used to assess the biomechanical features of the thoracic paravertebral muscles on concave and convex side in adolescent idiopathic scoliosis patients with Lenke 1-3 curves. The Cobb angle of the main curve was measured using the anteroposterior whole spine radiograph in the standing position. Findings A total of 40 adolescent idiopathic scoliosis patients with a mean Cobb angle of 66.49° (SD 32.8°) were included in this study. Muscle tone, stiffness and Deborah number on the concave side was significantly greater than that on the convex side. Relaxation time was significantly longer on the convex side than on the concave side. No statistically significant difference in muscle elasticity was observed between the concave side and the convex side (P > 0.05). Pearson correlation analysis demonstrated that stiffness on the concave side was moderately positively correlated with the Cobb angle (P < 0.05, r = 0.582); the Deborah number on both sides and the relaxation time on the concave side showed a moderate negative correlation with the Cobb angle (P < 0.05, r = −0.632; r = −0.432; r = −0.611). Interpretation Concave paravertebral muscle tone and stiffness were greater than those on convex side in adolescent idiopathic scoliosis patients. The asymmetric biomechanical characteristics of paravertebral muscles are closely related to the severity of scoliosis.