Significant Ventilatory Functional Restriction in Adolescents with Mild or Moderate Scoliosis During Maximal Exercise Toleramce Test

· (a – Impiva [Spain]: Instituto Mediana y Peque a Empresa De Valencia)

Purpose: To evaluate cardio-pulmonary functional restrictions during a maximal exercise tolerance test in AIS patients with mild curves and compare to results obtained in healthy schhoolar of the same age.

Methods: 23 girls with AIS with an average age of 13.5 years (range, 10-16) and an average scolitic curve of 27º Cobb (range, 20-45) were studied by basal spirometry and dynamic ventilatory parameters during a maximal exercise tolerance test. Similar studies were performed in a control group of 5 healthy girls matched in age. Exercise test consisted of a ramp protocol on treadmill starting at a speed of 0.75 m/sg (2.7 km/h) with increments of 0.2 m/s (0.72 km/h) per minute. The slope remained constant at 1.5%. During the test, girls move from walking to running on their own accord. All subjects completed the test to exhaustion to determine maximal oxygen uptake (VO max). ECG was continously monitorized during the tolerance exercise test.

Results:

There were no differences between scoliotic and healthy girls in basal ventilatory parameters (FVC, FEV1). AIS patients showed worse tolerance to exercise test with lower maximal speed average (31% lower than controls), lower ventilatory efficiency at maximal exercise (31% deficit), early anaerobic thresold, and a lower aerobic power expressed by decreased body mass normalized VO max (29% restriction). Heart rate and respiratory coefficient were similar in both groups indicating that tolerance test was performed at similar maximal conditions.

Conclusions: Although patients with mild or moderate scoliosis do not exhibit cardio-pulmonary restrictions in basal static conditions, they have a significant lower tolerance to maximal and submaximal exercise. This finding is expressed by a lower aerobic power and a lower anaerobic capacity, both related to ventilatory restriction at maximal exercise.

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