When Will You Succeed Casting Patients With Early-onset Scoliosis? Prospective Evaluation of Predictive Radiographic Parameters

Abstract

Background: In a recent retrospective study, in cast correction of the major curve correlated with final curve size in patients with early-onset scoliosis treated with casting. We therefore sought to perform a prospective study with controlled methodology to determine if there are parameters associated with reduction of coronal deformity. Methods: A prospective, observational study was conducted between 2014 and 2019 at selected sites willing to comply with a standard radiographic and follow-up protocol. Radiographic data was collected at time points of precast, in traction, initial in-cast, and at minimum 1 year follow-up. Multivariate linear regression models were utilized to control for potential confounders using a stepwise procedure. Twenty-nine patients met inclusion criteria. Results: On multivariate analysis, traction major curve (P=0.043) and initial in-cast (P=0.011) major curve Cobb angles were independently associated with final out of cast major curve Cobb angle. The only factor that was independently associated with failure to cure (<15-degree major curve) was traction major curve Cobb angle (P=0.046). A threshold traction major curve Cobb angle of 20 degrees was found to have good accuracy with 81% sensitivity and 73% specificity (receiver operator curve area: 0.869, P<0.001). A traction major curve Cobb angle over 20 degrees would accurately predict failure of casting treatment to cure scoliosis in 79% of cases. A threshold in-cast major curve Cobb angle of 21 degrees was found to have slightly less accuracy than traction with 69% sensitivity, 82% specificity, and 74% accuracy (receiver operator curve area: 0.830, P=0.004). Conclusions: Radiographic measurements in traction and initially in the cast are predictive of curve size at follow-up for children with early-onset scoliosis treated with casting. The standardization and utility of traction films should be further explored. Level of Evidence: Level II.

Early-onset scoliosis

“…In a multicenter, retrospective study, Fedorak et al [12] found that children who underwent casting prior to 18 months of age were more likely to have a major curve of less than 15° at a minimum 2-year follow-up after casting. Glotzbecker et al found similar results [13]. While recognizing the importance of early detection and treatment, other authors have highlighted the risk of over treatment, arising the doubt of how many of these patients could have experienced spontaneous resolution without any treatment [14].…”