3D correction of AIS in braces designed using CAD-CAM and FEM: a randomized controlled trialReport as inadecuate

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Scoliosis and Spinal Disorders

, 12:24

First Online: 23 July 2017Received: 21 September 2016Accepted: 16 June 2017


BackgroundRecent studies showed that finite element model FEM combined to CAD-CAM improves the design of braces for the conservative treatment of adolescent idiopathic scoliosis AIS, using 2D measurements from in-brace radiographs. We aim to assess the immediate effectiveness on curve correction in all three planes of braces designed using CAD-CAM and numerical simulation compared to braces designed with CAD-CAM only.

MethodsSRS standardized criteria for bracing were followed to recruit 48 AIS patients who were randomized into two groups. For both groups, 3D reconstructions of the spine and patient’s torso, respectively built from bi-planar radiographs and surface topography, were obtained and braces were designed using the CAD-CAM approach. For the test group, 3D reconstructions of the spine and patient’s torso were additionally used to generate a personalized FEM to simulate and iteratively improve the brace design with the objective of curve correction maximization in three planes and brace material minimization.

ResultsFor the control group CtrlBraces, average Cobb angle prior to bracing was 29° thoracic, T and 25° lumbar, L with the planes of maximal curvature PMC respectively oriented at 63° and 57° on average with respect to the sagittal plane. Average apical axial rotation prior to bracing was 7° T and 9° L. For the test group FEMBraces, initial Cobb angles were 33° T and 28° L with the PMC at 68° T and 56° L and average apical axial rotation prior to bracing at 9° T and L. On average, FEMBraces were 50% thinner and had 20% less covering surface than CtrlBraces while reducing T and L curves by 47 and 48%, respectively, compared to 25 and 26% for CtrlBraces. FEMBraces corrected apical axial rotation by 46% compared to 30% for CtrlBraces.

ConclusionThe combination of numerical simulation and CAD-CAM approach allowed designing more efficient braces in all three planes, with the advantages of being lighter than standard CAD-CAM braces. Bracing in AIS may be improved in 3D by the use of this simulation platform. This study is ongoing to recruit more cases and to analyze the long-term effect of bracing.

Trial registrationClinicalTrials.gov, NCT02285621

KeywordsComputer-aided design-computer-aided manufacturing Scoliosis Thoraco-lumbo-sacral orthosis Finite element model FEM RCT Abbreviations3DThree-dimensional

AISAdolescent idiopathic scoliosis

CAD-CAMComputer-aided design-computer-aided manufacturing

FEMFinite element model




PMCPlane of maximum curvature

RCTRandomized controlled trial


TLSOThoraco-lumbo-sacral orthosis

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Author: Nikita Cobetto - Carl-Éric Aubin - Stefan Parent - Soraya Barchi - Isabelle Turgeon - Hubert Labelle

Source: https://link.springer.com/

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