Spinal factors affecting pulmonary function in patients with scoliosis.

ABSTRACT

OBJECTIVE: To investigate pulmonary function impairment and the spinal factors that may determine pulmonary function in patients with scoliosis. METHODS: Seventy-eight patients with idiopathic scoliosis or congenital scoliosis and 78 age- and gender-matched healthy subjects were enrolled in this study. The radiographic parameters of spinal deformity were obtained from patients with scoliosis. Both two groups received pulmonary function tests. RESULTS: Patients with scoliosis demonstrated a restrictive pattern of pulmonary function impairment with a proportional decrease in both forced expiratory volume in one second and forced vital capacity. Total lung capacity and functional residual capacity were reduced. Carbon monoxide diffusion capacity was decreased, while diffusion coefficient remained normal or slightly higher. Airway resistance and conductance were not affected. In addition, airway resistance and residual volume were found abnormal in patients with congenital scoliosis. Multiple linear regression analysis showed that three spinal factors including involved thoracic vertebrae, vertical height from C7 to S1, and Cobb angle were independently responsible for 40%-51% of total variances of forced vital capacity, forced expiratory volume in one second, total lung capacity, and functional residual capacity. CONCLUSIONS: Patients with scoliosis have restrictive ventilation defects. More thoracic vertebrae involvement, lower vertical height, and larger Cobb angle are associated with severer impairment of lung volume.