The height gain in scoliotic deformity correction: assessed by new predictive formula

Height gain after scoliosis correction is of a special interest for the patient and family. Ylikoski was the first to suggest a formula predicting height loss in untreated scoliotic patients. Stokes has recently suggested a new formula by using Cobb angle to determine height loss in idiopathic curves. We hypothesized that new additional variables to Cobb angle such as apical vertebral translation (AVT), number of instrumented segments (N), and disc heights may increase the accuracy of predicted height gain. According to our findings simple expression for height gain by simplified version of the formula is: SPΔH = 0.0059X(1)θ(1) + 2.3(1 - (θ(2)/θ(1)))N, where θ(1) is preoperative Cobb angle, X(1) is preoperative AVT, θ(2) is postoperative Cobb angle, and N is the number of instrumented vertebra. The purpose of this study is to analyze a new mathematical formula to predict height gain after scoliotic deformity correction.