Effects of short term cast wearing on respiratory and cardiac responses to submaximal and maximal exercise in adolescents with idiopathic scoliosis

AIM: Bracing is widely used to treat adolescent scoliosis. However, bracing may also affect respiratory and cardiovascular function. In this thirteen-weeks longitudinal study we evaluated the effect of brace wearing on maximal and submaximal cardiorespiratory capacity in adolescents with moderate idiopathic scoliosis. METHODS: Eight boys and 8 girls (12-18 years) with scoliosis of the thoracic spine (Cobb angle range 32 degrees - 42 degrees in boys and 32 degrees - 60 degrees in girls) were enrolled. Respiratory basal function (forced vital capacity, FVC, and forced expired volume in 1 s, FEV(1)) and cardiorespiratory adjustments to submaximal and maximal cycle ergometer exercise (heart rate, HR, pulmonary ventilation, VE, and oxygen consumption, VO(2)) were measured a week before fitting a brace, after 1 and 12 weeks of brace wearing, and a week after brace removal. RESULTS: With respect to pretreatment values: a) after 1 week of brace wearing FVC and FEV(1) were significantly reduced in both genders; b) after 12 weeks of bracing the amount of oxygen consumed per heart beat was reduced during maximal and submaximal exercises in females only; c) ventilatory efficiency was unchanged in both genders in each condition; d) oxygen uptake during maximal exercise was decreased (by about 10-20%) in females only; e) after brace removal all variables tended to regress to pretreatment values. CONCLUSIONS: Although data are preliminary and need to be confirmed on larger samples of patients, the brace appears to limit maximal exercise performance especially in girls, where it affects the cardiopulmonary efficiency. Thus, moderate physical exercise during brace wearing is advised to counteract respiratory, cardiovascular and muscle inefficiency due to ribcage movement limitations.