A new risk classification rule for curve progression in adolescent idiopathic scoliosis

BACKGROUND CONTEXT: Prognostic factors for curve progression of adolescent idiopathic scoliosis (AIS) have been reported previously. There is only one existing rule that classifies AIS patients into two groups by a curvature of 25 degrees. PURPOSE: This study aimed to develop a more refined risk classification rule for AIS. STUDY DESIGN: This was a retrospective cohort study. PATIENT SAMPLE: We examined 2,308 untreated AIS patients, aged 10 years and older, who had a Risser sign of 2 and lesser and a curvature less than 30 degrees at presentation. OUTCOME MEASURES: Outcome was taken as the time to progression to 30 degrees. METHODS: Patients' clinical parameters were analyzed by Classification and Regression Tree analysis. RESULTS: The new classification rule identified four risk groups of curve progression. Patients with a curvature of 26 degrees and more and less than 18 degrees constituted the highest and lowest risk groups, respectively. The two intermediate groups were identified by the age (11.3 years), menarcheal status, and body height (154 cm). CONCLUSIONS: The risk classification rule only uses information at the first presentation and can aid physicians in deriving an efficient management. (C) 2012 Elsevier Inc. All rights reserved.