Aymeric Guy1,2, Maxence Coulombe2,3, Hubert Labelle2,3, Manuel Rigo4, Man-Sang Wong5, Babak Hassan Beygi5, James Wynne6, Michael Timothy Hresko7,8, Eric Ebermeyer9,10, Philippe Vedreine11, Xue-Cheng Liu12, John G Thometz12, Benoît Bissonnette13, Charlotte Sapaly14, Soraya Barchi2, Carl-Éric Aubin1. 1. Polytechnique Montreal, Montreal, Quebec, Canada. 2. Sainte-Justine University Hospital Center, Montreal, Quebec, Canada. 3. Surgery Department, University of Montreal, Montreal, Quebec, Canada. 4. Institute Rigo Quera Salvá S.L.P. Scoliosis Rehabilitation Center, Barcelona, Spain. 5. Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, China. 6. Boston Orthotics and Pros-thetics, Avon, MA. 7. Department of Orthopaedic Surgery, Harvard Medical School, Boston, MA. 8. Boston Children's Hospital, Boston, MA. 9. LBM/Georges Charpak Human Biomechanics Institute, Arts et Métiers ParisTech, Paris, France. 10. Spine Unit, Bellevue University Hospital Center, Saint-Étienne, France. 11. Sas Lagarrigue Lyon, Villeurbanne, France. 12. Department of Orthopedic Surgery, Children's Hospital of Wisconsin, Medical College of Wisconsin; Milwaukee, WI. 13. Orthèse-Prothèse Rive-Sud, Longueuil, Canada. 14. Rodin4D, Merignac, France.
Abstract
STUDY DESIGN: Multicenter numerical study. OBJECTIVE: To biomechanically analyze and compare various passive correction features of braces, designed by several centers with diverse practices, for three-dimensional (3D) correction of adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: A wide variety of brace designs exist, but their biomechanical effectiveness is not clearly understood. Many studies have reported brace treatment correction potential with various degrees of control, making the objective comparison of correction mechanisms difficult. A Finite Element Model simulating the immediate in-brace corrective effects has been developed and allows to comprehensively assess the biomechanics of different brace designs. METHODS: Expert clinical teams (one orthotist and one orthopedist) from six centers in five countries participated in the study. For six scoliosis cases with different curve types respecting SRS criteria, the teams designed two braces according to their treatment protocol. Finite Element Model simulations were performed to compute immediate in-brace 3D correction and skin-to-brace pressures. All braces were randomized and labeled according to 21 design features derived from Society on Scoliosis Orthopaedic and Rehabilitation Treatment proposed descriptors, including positioning of pressure points, orientation of push vectors, and sagittal design. Simulated in brace 3D corrections were compared for each design feature class using ANOVAs and linear regressions (significance P ≤ 0.05). RESULTS: Seventy-two braces were tested, with significant variety in the design approaches. Pressure points at the apical vertebra level corrected the main thoracic curve better than more caudal locations. Braces with ventral support flattened the lumbar lordosis. Lateral and ventral skin-to-brace pressures were correlated with changes in thoracolumbar/lumbar Cobb and lumbar lordosis (r =- 0.53, r = - 0.54). Upper straps positioned above T10 corrected the main thoracic Cobb better than those placed lower. CONCLUSIONS: The corrective features of various scoliosis braces were objectively compared in a systematic approach with minimal biases and variability in test parameters, providing a better biomechanical understanding of individual passive mechanisms' contribution to 3D correction.
STUDY DESIGN: Multicenter numerical study. OBJECTIVE: To biomechanically analyze and compare various passive correction features of braces, designed by several centers with diverse practices, for three-dimensional (3D) correction of adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: A wide variety of brace designs exist, but their biomechanical effectiveness is not clearly understood. Many studies have reported brace treatment correction potential with various degrees of control, making the objective comparison of correction mechanisms difficult. A Finite Element Model simulating the immediate in-brace corrective effects has been developed and allows to comprehensively assess the biomechanics of different brace designs. METHODS: Expert clinical teams (one orthotist and one orthopedist) from six centers in five countries participated in the study. For six scoliosis cases with different curve types respecting SRS criteria, the teams designed two braces according to their treatment protocol. Finite Element Model simulations were performed to compute immediate in-brace 3D correction and skin-to-brace pressures. All braces were randomized and labeled according to 21 design features derived from Society on Scoliosis Orthopaedic and Rehabilitation Treatment proposed descriptors, including positioning of pressure points, orientation of push vectors, and sagittal design. Simulated in brace 3D corrections were compared for each design feature class using ANOVAs and linear regressions (significance P ≤ 0.05). RESULTS: Seventy-two braces were tested, with significant variety in the design approaches. Pressure points at the apical vertebra level corrected the main thoracic curve better than more caudal locations. Braces with ventral support flattened the lumbar lordosis. Lateral and ventral skin-to-brace pressures were correlated with changes in thoracolumbar/lumbar Cobb and lumbar lordosis (r =- 0.53, r = - 0.54). Upper straps positioned above T10 corrected the main thoracic Cobb better than those placed lower. CONCLUSIONS: The corrective features of various scoliosis braces were objectively compared in a systematic approach with minimal biases and variability in test parameters, providing a better biomechanical understanding of individual passive mechanisms' contribution to 3D correction.
Authors: Patrick Strube; Chris Lindemann; Max Bahrke; Steffen Brodt; André Sachse; Lya I Reich; Alexander Hoelzl; Timo K Zippelius Journal: Children (Basel) Date: 2022-05-03