Factors determining the final outcome of treatment of idiopathic scoliosis with the Boston brace: a longitudinal study.

This study tries to determine factors influencing the final outcome of treatment of idiopathic scoliosis with the Boston brace and to compare the results with the natural history. One hundred and fifty-one patients, 130 girls and 21 boys, treated between 1982 and 1991, were reviewed. A series of continuous and categorical variables were measured, allowing for the construction of a multiple regression equation. Continuous variables were age at discovery of the curve, time of interval between discovery and treatment and age at the beginning of treatment. Furthermore age of menarche, duration of treatment, duration of weaning and age and time of follow-up were noted. Continuous numerical variables were the Cobb angle, the apical vertebral rotation, and the Risser stage. Categorical variables consisted of the results of a questionnaire and the King's classification of the curve. Good results are achieved in older children, with low Cobb angles and advanced maturity, who are, however, the very ones not expected to progress, as also indicated in studies on natural history. Brace treatment seems not to alter the natural history in general, and especially not in the older child; this is the case from age 12 years and Risser stage 2 onwards. In the younger child, a brace is probably still indicated, because it has been proved that a scoliosis is more prone to progress and that a possible positive result can still not be ruled out, as long as randomized control trials are not conducted.