A Novel Low-Cost Three-Dimensional Printed Brace Design Method for Early Onset Scoliosis

Abstract

Early onset scoliosis (EOS) is a type of spine deformity that presents before 10 years of age. The biomechanical properties in scoliosis have been found to be different, especially in the case of the concave and convex paravertebral muscles. Based on this fact, a novel three-dimensional (3D) printed patient-specific asymmetric stiffness brace design method is proposed in this paper, aiming to provide asymmetric stiffness to match “imbalanced” biomechanical properties of the concave and convex paravertebral muscles, respectively, and treat EOS by applying the block-structure brace. A 3D computer aided design draft model of the brace contour was implemented from 3D scanning. The asymmetric stiffness block-structure brace was designed in Rhinoceros and the finite element (FE) model was imported into abaqus. FE simulation was employed to study the mechanical characteristics of the brace, which provided a quantitative index for the imbalanced property of brace stiffness. The results of the FE simulation showed that the stiffnesses of the concave and convex sides were 145.88 N/mm and 35.95 N/mm, respectively. The block-structure brace was fabricated using 3D printing. Asymmetric stiffness was evaluated by corrective force measurements, which were obtained from a thin-film pressure sensor equipped on the brace. The patient-specific asymmetric stiffness brace was applied to clinical practice in a one-year-old EOS patient. A novel low-cost 3D printed brace design method for EOS was proposed in this study that could potentially be useful in patient treatment acceptance.