使用计算机辅助设计/计算机辅助制造（CAD/CAM）和有限元法（FEM）设计的支具对青少年特发性脊柱侧弯（AIS）进行三维矫正：一项随机对照试验。
3D correction of AIS in braces designed using CAD/CAM and FEM: a randomized controlled trial.
作者信息
Cobetto Nikita, Aubin Carl-Éric, Parent Stefan, Barchi Soraya, Turgeon Isabelle, Labelle Hubert
机构信息
Department of Mechanical Engineering, Polytechnique Montreal, P.O. Box 6079, Downtown Station, Montreal, Quebec H3C 3A7 Canada.
出版信息
Scoliosis Spinal Disord. 2017 Jul 23;12:24. doi: 10.1186/s13013-017-0128-9. eCollection 2017.
BACKGROUND
Recent 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.
METHODS
SRS 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.
RESULTS
For 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.
CONCLUSION
The 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 REGISTRATION
ClinicalTrials.gov, NCT02285621.
背景
最近的研究表明，有限元模型（FEM）与CAD/CAM相结合，利用支具内X光片的二维测量数据，可改善青少年特发性脊柱侧凸（AIS）保守治疗支具的设计。我们旨在评估与仅使用CAD/CAM设计的支具相比，使用CAD/CAM和数值模拟设计的支具在三个平面上对曲线矫正的即时效果。
方法
遵循脊柱侧凸研究学会（SRS）的支具标准化标准招募48例AIS患者，并将其随机分为两组。两组均通过双平面X光片和表面形貌分别获得脊柱和患者躯干的三维重建图像，并使用CAD/CAM方法设计支具。对于试验组，额外利用脊柱和患者躯干的三维重建图像生成个性化有限元模型，以模拟并迭代改进支具设计，目标是在三个平面上使曲线矫正最大化，并使支具材料最小化。
结果
对于对照组（CtrlBraces），支具佩戴前平均Cobb角为胸椎（T）29°、腰椎（L）25°，最大曲率平面（PMC）相对于矢状面的平均角度分别为63°和57°。支具佩戴前平均顶椎轴向旋转角度为胸椎7°、腰椎9°。对于试验组（FEMBraces），初始Cobb角为胸椎33°、腰椎28°，PMC为胸椎68°、腰椎56°，支具佩戴前平均顶椎轴向旋转角度为胸椎和腰椎均9°。平均而言，FEMBraces比CtrlBraces薄50%，覆盖面积小20%，同时胸椎和腰椎曲线分别减少47%和48%，而CtrlBraces分别减少25%和26%。FEMBraces使顶椎轴向旋转矫正46%，而CtrlBraces为30%。
结论
数值模拟与CAD/CAM方法相结合能够在三个平面上设计出更有效的支具，具有比标准CAD/CAM支具更轻的优点。使用该模拟平台可能会改善AIS的三维支具治疗。本研究正在招募更多病例并分析支具的长期效果。
试验注册
ClinicalTrials.gov，NCT02285621。
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