• Lori A Dolan, Stuart L Weinstein, Matthew B Dobbs, John M Jack Flynn, Daniel W Green, Matthew F Halsey, M Timothy Hresko, Walter F Krengel, Charles T Mehlman, Todd A Milbrandt, Peter O Newton, Nigel Price, James O Sanders, Michael L Schmitz, Richard M Schwend, Suken A Shah, Kit Song, and Vishwas Talwalkar.
• University of Iowa, Iowa City, IA.
• Spine. 2024 Feb 1; 49 (3): 147156147-156.

Study DesignProspective multicenter study data were used for model derivation and externally validated using retrospective cohort data.ObjectiveDerive and validate a prognostic model of benefit from bracing for adolescent idiopathic scoliosis (AIS).Summary Of Background DataThe Bracing in Adolescent Idiopathic Scoliosis Trial (BrAIST) demonstrated the superiority of bracing over observation to prevent curve progression to the surgical threshold; 42% of untreated subjects had a good outcome, and 28% progressed to the surgical threshold despite bracing, likely due to poor adherence. To avoid over-treatment and to promote patient goal setting and adherence, bracing decisions (who and how much) should be based on physician and patient discussions informed by individual-level data from high-quality predictive models.Materials And MethodsLogistic regression was used to predict curve progression to <45° at skeletal maturity (good prognosis) in 269 BrAIST subjects who were observed or braced. Predictors included age, sex, body mass index, Risser stage, Cobb angle, curve pattern, and treatment characteristics (hours of brace wear and in-brace correction). Internal and external validity were evaluated using jackknifed samples of the BrAIST data set and an independent cohort (n=299) through estimates of discrimination and calibration.ResultsThe final model included age, sex, body mass index, Risser stage, Cobb angle, and hours of brace wear per day. The model demonstrated strong discrimination ( c -statistics 0.83-0.87) and calibration in all data sets. Classifying patients as low risk (high probability of a good prognosis) at the probability cut point of 70% resulted in a specificity of 92% and a positive predictive value of 89%.ConclusionThis externally validated model can be used by clinicians and families to make informed, individualized decisions about when and how much to brace to avoid progression to surgery. If widely adopted, this model could decrease overbracing of AIS, improve adherence, and, most importantly, decrease the likelihood of spinal fusion in this population.Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.

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