Impact of Scoliosis Severity on Functional Capacity in Patients With Adolescent Idiopathic Scoliosis.

Purpose: The aim of this study is to evaluate the walked distance and physiological responses during incremental shuttle walk test in patients with different degrees of adolescent idiopathic scoliosis (AIS).

Methods: We evaluated 20 healthy teenagers and 46 patients with AIS; they were divided into 2 groups: AIS > 45° and AIS < 45°. The volunteers performed an incremental shuttle walk test, and the following physiological responses were quantified: oxygen consumption, tidal volume, ventilation, and the incremental shuttle walked distance. Respiratory muscle strength was quantified, pulmonary function test was performed, and the forced vital capacity and expiratory volume in the first second were obtained.

Results: Patients with AIS > 45° presented significant reduced incremental shuttle walked distance compared with the AIS < 45° and control group [447 (85), 487 (95), and 603 (85), respectively]. Patients with AIS also showed reduced forced vital capacity (P = .001) and expiratory volume in the first second (P = .005) compared with control group. Moderate correlations between forced vital capacity (r = -.506) and tidal volume (r = -.476) with scoliosis angles were found.

Conclusions: The incremental shuttle walk test was capable of identifying reduced functional capacity in patients with different degrees of AIS. Moreover, the severity of spinal curvature may exert influence on ventilatory and metabolic variables.