Rib-vertebral angle measurements predict brace treatment outcome in Risser grade 0 and premenarchal girls with adolescent idiopathic scoliosis.

PURPOSE: To investigate the predictive role of rib-vertebral angle (RVA) measurements in early adolescent idiopathic scoliosis (AIS) girls with right thoracic curve during brace treatment.

METHODS: Early AIS (premenarchal and Risser 0) girls who had undergone brace treatment and had been followed regularly were recruited to this study. According to the bracing outcome, they were divided into Group A (non-progressed) and Group B (curve worsened over six degrees or indicated for surgery).

RESULTS: Totally 48 girls were included. There were 30 and 18 patients in Groups A and B, respectively. Ratio of curve progression was significantly higher in patients with initial RVA difference (RVAD) ≥20° versus <20°, or convex RVA (CRVA) ≤68° versus >68°. From brace initiation to the latest follow-up, CRVA was found to be significantly higher in Group A versus Group B (P < 0.05), while RVAD was higher in Group B versus Group A (P < 0.05). Serial measurements revealed an increasing trend for RVAD (from 19 ± 10° to 29 ± 8°) yet a decreasing trend for CRVA (from 68 ± 6° to 60 ± 7°) in Group B, but both RVAD and CRVA were found to remain stable in Group A during the follow-up period. Association analyses showed that both RVAD ≥20° and CRVA ≤68° at brace initiation and at each follow-up were significantly associated with curve progression.

CONCLUSIONS: The initial RVAD ≥20° and CRVA ≤68° serve as valid factors in predicting the risk of curve progression during bracing in early AIS. Constant watch on RVAD and CRVA can help to more accurately predict the effectiveness of bracing in these patients.