The Influence of Body Habitus on Documented Brace Wear and Progression in Adolescents with Idiopathic Scoliosis

Background:Although studies have been published stating obese patients are less compliant with brace use, no objective studies measuring hours of daily brace wear have been performed to correlate brace wear and success with body mass index (BMI). The purpose of this study was to establish the relationship between BMI and brace compliance, and between BMI and progression to surgical magnitude of 50 degrees or more.Methods:A total of 175 adolescents were prescribed thoracolumbarsacral orthosis for the treatment of an adolescent idiopathic scoliosis and followed to completion of treatment. BMI was measured at brace prescription, and divided into: (1) underweight (< 5th percentile), (2) normal (>5th, <85%), (3) overweight (>85%, <95%), and (4) Obese (>95%). Thermochron sensors were used to measure compliance. Radiographs were measured at brace prescription, and at time of brace discontinuation or surgery. Outcome was classified as successful if curve magnitude was <50 degrees and no surgery was performed.Results:The underweight group wore their braces more hours than the other groups (15.7 h low, 12.5 h normal, 11.7 h high, and 9.0 h obese BMI (low vs. normal P=0.031, low vs. high P=0.01, low vs. obese P=0.01). The underweight group had the highest rate of surgical progression (60%), compared with 27.7% of normal BMI teens, 28.6% of overweight patients, and 55.6% of obese patients. The low BMI had a significantly higher rate of surgery than the normal BMI group (P=0.01).Conclusions:Although overweight and obese patients wear orthoses the least hours daily, the highest surgical risk is in underweight adolescents despite good compliance.Level of evidence:Level 2.