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

C.F. Lee, Daniel Y.T. Fong, Kenneth M.C. Cheung, Jack C.Y. Cheng, Bobby K.W. Ng, T.P. Lam, Paul S.F. Yip, Keith D.K. Luk, 
    
A new risk classification rule for curve progression in adolescent idiopathic scoliosis, The Spine Journal, Available online 21 June 2012, ISSN 1529-9430, 10.1016/j.spinee.2012.05.009.  (http://www.sciencedirect.com/science/article/pii/S1529943012003300)    
Abstract: 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°.    
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° at presentation.  Outcome measures  Outcome was taken as the time to progression to 30°.    
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° and more and less than 18° 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.  Keywords: Adolescent idiopathic scoliosis; Classification and regression tree; Classification rule; Curve progression; Prognostic factors