Preoperative 6-Minute Walk Performance in Children With Congenital Scoliosis

BACKGROUND The 6-minute walk test (6MWT) is used to assess the function of cardiopulmonary and neuromuscular conditions in adults and children. The primary research question was to determine the relationship between 6MWT distance and forced vital capacity (FVC) and the major curve among children with congenital scoliosis with rib anomalies. METHODS The authors recorded 6MWT distance in meters, FVC as a percentage of predicted normal value using arm span for height (FVC%), and Cobb angle in 20 children (13 girls; average age, 6.7±1.3 y) with congenital scoliosis before outpatient surgical treatment. The 6MWT uses a standardized protocol and measures distance traveled in 6 minutes on a flat surface. The authors then determined the correlation between these measures using linear regression analysis. RESULTS The Cobb angle of the major curvature was 55.4±20.5 degrees. The type of vertebral anomaly was mixed in 17 cases, formation failure in 2 cases, and segmentation failure in 1 case. The range of rib anomalies was 3.4±3.9 levels; 15 and 5 patients, respectively, had unilateral and bilateral rib anomalies. FVC and FVC% were 0.7±0.2 L and 60%±19%, respectively. The ratio of forced expiratory volume at 1 second to FVC (FEV1/FVC), which indicates obstructive lung disease, was normal at 93%±7%. The 6MWT distance was 386.3±59.4 m, which was ≤10% of the predicted distance for normal children. No child was able to walk the normal distance on the basis of published norms. 6MWT distance was significantly correlated with arm span (ρ=0.46, P=0.04) and major curve (ρ=-0.61, P=0.004), but not with FVC% (ρ=0.17, P=0.49). CONCLUSIONS The 6MWT distance is a feasible measure of function and is substantially reduced before surgery in children with thoracic congenital scoliosis with rib anomalies. The 6MWT distance was significantly correlated with a major curve but not with FVC%. 6MWT distance is not affected by moderate lung function impairment. LEVEL OF EVIDENCE Level IV-retrospective cohort study.