Chest wall motion capture as a reliable method for assessing pulmonary function in idiopathic scoliosis K. Nicholson 1 , J. Salazar-Torres 2 , P. Gabos 2 , F. Miller 2 , J. Henley 2 , S. Shah 2 1 Wake Forest Baptist Medical Center, Orthopaedic Surgery, Winston Salem, USA 2 Nemours/Alfred I. duPont Hospital for Children, Orthopedics, Wilmington, USA Introduction Scoliosis is the most common spinal disorder in children and ado- lescents[1]. Reported prevalence in the general population is 15.3%[2]. In scoliosis, distortion of the rib cage alters lung function by reducing chest wall compliance and excursion and rotating intrathoracic contents into the lung cavity [3–5]. There is substantial interest in the relation- ship between spinal deformity and pulmonary function due to the high rates of morbidity and mortality when scoliosis results in pulmonary impairment [2,6]. Several studies have found no correlation between typical scoliotic deformity measures, such as Cobb angle, and pulmonary function suggesting the need for independent measures of lung function [3,4,6–11]. Pulmonary function tests (PFTs) are state of the art tech- niques for measuring pulmonary function. However, these require a face mask and cooperation [3] and are therefore not feasible for infantile, juvenile, or intellectually impaired spinal deformity patients who cannot comply with PFT protocols, but who are at increased risk for respiratory morbidity [10–12]. Computed tomographic-based volumetric re- constructions are an alternative to PFTs that allow for regional lung analysis, but involve signifcant radiation and are unable to capture functional pulmonary measures. Since motion of the chest wall during breathing is measurable and can be used to monitor pulmonary function without the need for face masks or excessive radiation, we are proposing to utilize motion capture to measure pulmonary function in pediatric patients with idiopathic scoliosis [13]. Research Question Are changes in lung volume (ΔVL) during breathing, as estimated with a 3D geometric model, correlated with ΔVL measured with a pul- monary function test (PFT)? Methods Children between 7 and 17 y/o with diagnosis of idiopathic scoliosis (IS) were recruited from the hospital scoliosis clinic. MoCap data and breathing volume were collected simultaneously using 12 Qualisys Oqus 7 cameras and a breath-by-breath metabolic unit respectively. Each subject wore a contour conforming shirt featuring 70 retrorefective circles arranged in a grid type pattern. Subjects were asked to both inhale and then exhale to their maximum ability. Custom software was used to create a geometric model from motion capture data. VL was Figure 1. Contents lists available at ScienceDirect Gait & Posture journal homepage: www.elsevier.com/locate/gaitpost https://doi.org/10.1016/j.gaitpost.2020.08.014 0966-6362/© 2020 Published by Elsevier Ltd. Gait & Posture 81 (2020) 238–239