Serial Mehta Cast Utilization in Infantile Idiopathic Scoliosis: Evaluation of Radiographic Predictors

Mehta cast utilization has gained a considerable momentum as a nonoperative treatment modality for the initial management of infantile idiopathic scoliosis (IIS). Despite its acceptance, there is paucity of data that characterize the radiographic parameters associated with Mehta casting and the factors correlated with a sustained curve correction.

A retrospective review of IIS patients who underwent Mehta casting was performed with a mean 2-year follow-up. X-rays were evaluated at each visit for the Cobb angle, focal deformity, rib-vertebral angle difference, and height of concavity and convexity of the apical 3 vertebrae. Concave-to-convex height ratios were calculated and tracked for each patient. Radiographic parameters were compared from precasting to after final casting, and from final casting to most recent follow-up.

A total of 45 patients were identified, of whom 18 (40%) were male and 27 (60%) were female, with a mean age of 18.8±9.5 months at first casting and a mean follow-up of 37.7±19.7 months. Following final casting, the mean Cobb angle (25.6 vs. 52.7 degrees), focal deformity (17.4 vs. 30.5 degrees), rib-vertebral angle difference (18 vs. 32.3 degrees), and the concave-to-convex height ratios improved relative to precast parameters, respectively (P<0.001). At final follow-up, mean Cobb angle (16.2 vs. 25.6 degrees) and concave-to-convex height ratios progressively improved when compared with final cast measurements, respectively (P<0.001). Five (11%) patients did not demonstrate sustained curve correction at final follow-up, whereas 4 (9%) required growing-rod placement. Lastly, the regression analysis demonstrated improvements in the focal deformity (17.4 vs. 30.5) and the concave-to-convex height ratios of the +1 and -1 apical vertebrae from the precast to last cast periods (P<0.001). These findings were correlated with sustained Cobb angle correction from cast removal to the most recent follow-up.

Radiographic parameters associated with control of progressive deformity for IIS include improvements in focal deformity and concave-to-convex height ratios for +1 and -1 apical vertebrae after final casting. Mehta casting is an effective treatment for symptomatic IIS and continues to provide IIS patients with significant curve correction.

Level IV.