Finite element modeling of the human thoracolumbar spine
Finite element modeling of the human thoracolumbar spine
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DOI：
10.1097/00007632-200303150-00009
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发表时间：
2003-03-15
期刊：
影响因子：
3
通讯作者：
Keaveny, TM
中科院分区：
文献类型：
--
作者：
Liebschner, MAK;Kopperdahl, DL;Keaveny, TM
研究设计。对实验数据进行校正后，采用有限元方法对尸体椎体的生物力学特性进行了参数化研究。建立并验证基于定量计算机断层扫描的人胸腰椎三维有限元模型。具体来说，将有限元建模与体外生物力学测试结合起来，避免了与直接测量壳性能相关的问题。背景资料摘要。有限元方法有助于了解椎体内的损伤机制和应力分布规律，是临床评估脊柱损伤的重要组成部分。由于椎体壳建模的复杂性，目前尚不清楚基于定量计算机层析成像的脊柱有限元模型是否能准确预测生物力学特性。我们开发了一种新的有限元建模技术，该技术基于19个放射学正常人体椎体的定量计算机断层扫描和圆柱形小梁骨标本的力学性能数据的实证研究。将椎体壳的结构特性识别为参数变量，并进行校准，以提供模型和实验之间整个椎体刚度的一致性。由此获得的壳体性能的平均值被用于所有模型中，以提供整个椎体强度和刚度的预测。将n = 19个计算机模型校准为实验刚度，得出椎体壳的平均有效模量为457 +/- 931 MPa，范围为9至3216 MPa。椎体壳有效模量与实验测量的刚度或平均小梁模量之间没有明显的相关性。使用所有19个模型的有效椎体壳模量，预测的椎体刚度是刚度（r(2) = 0.81）和强度（r(2) = 0.79）实验测量的良好预测因子。这些发现表明，使用恒定厚度0.35 mm和有效模量457 MPa的椎体壳建模，结合基于定量计算机断层扫描的骨小梁特性和椎体几何形状建模，可以准确预测整个椎体的生物力学特性。因此，使用这种建模技术应该对椎体生物力学行为有实质性的了解，并可能最终改善该队列骨折风险的临床指征。
Study Design. Biomechanical properties within cadaveric vertebral bodies were parametrically studied using finite element analysis after calibration to experimental data.Objectives. To develop and validate three-dimensional finite element models of the human thoracolumbar spine based on quantitative computed tomography scans. Specifically, combine finite element modeling together with in vitro biomechanical testing circumventing problems associated with direct measurements of shell properties.Summary of Background Data. Finite element methods can help to understand injury mechanisms and stress distribution patterns within vertebral bodies as an important part in clinical evaluation of spinal injuries. Because of complications in modeling the vertebral shell, it is not clear if quantitative computed tomography-based finite element models of the spine could accurately predict biomechanical properties.Methods. We developed a novel finite element modeling technique based on quantitative computed tomography scans of 19 radiographically normal human vertebra bodies and mechanical property data from empirical studies on cylindrical trabecular bone specimens. Structural properties of the vertebral shell were recognized as parametric variables and were calibrated to provide agreement in whole vertebral body stiffness between model and experiment. The mean value of the shell properties thus obtained was used in all models to provide predictions of whole vertebral strength and stiffness.Results. Calibration of n = 19 computer models to experimental stiffness yielded a mean effective modulus of the vertebral shell of 457 +/- 931 MPa ranging from 9 to 3216 MPa. No significant correlation was found between vertebral shell effective modulus and either the experimentally measured stiffness or the average trabecular modulus. Using the effective vertebral shell modulus for all 19 models, the predicted vertebral body stiffness was an excellent predictor of experimental measurements of both stiffness ( r(2) = 0.81) and strength (r(2) = 0.79).Conclusion. These findings indicate that modeling of the vertebral shell using a constant thickness of 0.35 mm and an effective modulus of 457 MPa, combined with quantitative computed tomography- based modeling of trabecular properties and vertebral geometry, can accurately predict whole vertebral biomechanical properties. Use of this modeling technique, therefore, should produce substantial insight into vertebral body biomechanical behavior and may ultimately improve clinical indications of fracture risk of this cohort.