Long-term alterations of respiratory function in adolescents wearing a brace for idiopathic scoliosis

Study Design. This is a prospective study. Objective. The authors investigated the effects of continuous bracing for idiopathic scoliosis on lung function variables at three consecutive time points over a 2-year period. Summary of Background Data. Only short-term results regarding lung function impairment caused by bracing exist. Methods. Thirty adolescents (aged 13.6 +/- 1.8 years) with primary idiopathic thoracic scoliosis of 28.7 degrees +/- 4.1 degrees and primary lumbar scoliosis of 26.5 degrees +/- 10.4 degrees wee treated with a Boston brace. All patients underwent pulmonary function studies at the beginning of brace treatment and 12 and 24 months after treatment initiation. The examinations were always performed while the patients wee sitting, in and out of the brace. Patients removed the brace for 1 hour before the measurements for non-brace-wearing were performed. Vital capacity, forced expiratory volume in 1.0 second, and minute ventilation were determined with a low inertia, low resistance bell spirometer. Lung volume, including total lung capacity and functional residual capacity, was recorded. Results. The primary thoracic scoliosis was corrected to 14.5 degrees +/- 4.0 degrees and the primary lumbar scoliosis to 13.0 degrees +/- 6.0 degrees. The values of the following parameters taken while the brace was worn wee significantly lower than those taken without the brace at all time points (one-way analysis of variance): vital capacity (P < 0.02), forced vital capacity (P < 0.03), functional residual capacity (P < 0.02), and residual volume (P < 0.05). Furthermore, the predicted negative residual volume and negative functional residual capacity values differed significantly in all time points from negative residual volume and negative functional residual capacity values of patients while wearing the Boston brace (P < 0.01 and P < 0.02, respectively). Conclusions. The results suggest that brace wearing for mild idiopathic scoliosis does not harm adolescent lung function over a 2-year period and is recommended for treatment of idiopathic scoliosis in early adolescence when the generally accepted criteria for bracing are fulfilled.