Effectiveness of suspension bending cast for early-onset scoliosis

PURPOSE: To evaluate the effectiveness of a novel suspension bending cast (SBC) technique for early-onset scoliosis (EOS) that enables coronal correction through suspension-assisted bending and facilitates derotational molding, and to identify factors associated with curve improvement. METHODS: A retrospective review was conducted on 49 patients with EOS who underwent SBC between 2011 and 2023. For inclusion, patients had to be < 10 years at casting initiation and have ≥ 2 years of follow-up. Curves were measured before the first cast, after the first cast, at the end of casting, and at final follow-up. We analyzed curve improvement, scoliosis type, rib phase, and rib-vertebral angle difference (RVAD). RESULTS: Median age at initial casting was 44 months (interquartile range [IQR] 25-78). The median number of casts was 3 (IQR 2-6); the median follow-up was 58 months (IQR 35.0-81.6). The median curve was 63° before casting, corrected to 21° in the first cast, and 67° at final follow-up. Of the 49 patients, 30.6% went from casting to definitive fusion, and an additional 30.6% underwent additional surgery before definitive fusion, while the remaining 38.8% were "cured" or remain under non-operative management. Time from first cast application to any surgery was 38.6 months (IQR 21.9-58.5). Curve improvement (from initial to final) was associated with higher initial correction rates. Idiopathic scoliosis demonstrated greater initial correction than non-idiopathic scoliosis. No differences were observed in final curve or correction rate based on rib phase or RVAD. CONCLUSION: Suspension bending casts showed high initial correction in patients with moderate to severe EOS and contributed to delayed surgical intervention. A higher correction rate after the first cast was associated with long-term curve improvement, indicating that initial correction of casting may be an important prognostic factor.