Cardiopulmonary functioning in adolescent patients with mild idiopathic scoliosis

This study measured the physical work capacity of adolescent subjects with idiopathic scoliosis to determine whether cardiopulmonary restrictions begin to occur in the early stages of the condition. Nineteen adolescents (four males, 15 females) between the ages of 10 and 17 years (means = 13.4), with idiopathic thoracic scoliosis, served as subjects. The mean scoliotic curve was 21.5 degrees. Each subject had his/her height, weight, and percent body fat (Lange caliper) recorded. Resting vital capacity and forced expiratory volume were evaluated using standardized clinical spirometry techniques. Work capacity was measured via a continuous graded incremental exercise tolerance test, using a treadmill. A running protocol was used. Heart rate was continuously monitored by an ECG, and a Beckman Metabolic Cart analyzed ventilation (VE), breathing rate (f), and oxygen uptake (VO2) every minute. Twelve of the subjects had vital capacity measures that were one or more standard deviations below normal and also had VO2max scores below 40ml/kg/min. Subjects with curves of 25 degrees or higher had a mean VO2max of 32.6ml/kg/min, while subjects with curves of less than 25 degrees had a mean VO2max of 42.6ml/kg/min. It appears that some pulmonary limitations begin even in mild curves. Curves greater than 25 degrees also appear to affect work capacity.