Six-minute walk test and pulmonary function in ambulatory children with early-onset scoliosis.

Abstract

The six-minute walk test (6MWT) measures aerobic function, but normative values for early-onset scoliosis (EOS) do not exist. This study assesses 1) 6MWT distances for children with EOS and standard deviations [SD] from age- and sex-matched normal controls, and 2) correlations between 6MWT and pulmonary function tests (PFTs). We performed a retrospective review of 6MWTs administered at a single institution from 2012 to 2023. PFTs were obtained: Forced vital capacity (FVC) percent (%) and forced expiratory volume in one second (FEV1) %. 163 ambulatory children with EOS whose average age was 10.7 ± 3.7 years (range: 3.6-18 yrs) performed a 6MWT. There were 80 congenital (C), 37 idiopathic (I), 17 neuromuscular (N) and 28 syndromic (S) children with curves averaging 69° ± 28°. Only 12% (20/163) walked within 1 SD of the mean. C/I walked farther than N/S (440 m vs. 373 m, p = 0.004) and demonstrated 6MWT SD's closer to controls (-3.0 vs. -3.9, p = 0.009). However, they still walked 150 m to 288 m less than controls depending on age and sex (well above the clinically important difference). 6MWT distance correlated with FEV1% (r = 0.29, p = 0.001) and FVC% (r = 0.27, p = 0.003). The 6MWT is an objective measure of functional community ambulation that correlates with PFTs in EOS patients. C/I performs closer to controls than N/S but demonstrate clinically significant aerobic functional compromise when compared to age- and sex-matched controls. The lack of objective functional data limits our understanding of treatment efficacy for EOS. Multi-center prospective research is warranted.