Modelling the Influence of Heterogeneous Annulus Material Property Distribution on Intervertebral Disk Mechanics
Modelling the Influence of Heterogeneous Annulus Material Property Distribution on Intervertebral Disk Mechanics
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DOI：
10.1007/s10439-014-1025-5
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发表时间：
2014-08-01
影响因子：
3.8
通讯作者：
Ferguson, Stephen J.
中科院分区：
文献类型：
--
作者：
Marini, Giacomo;Ferguson, Stephen J.
纤维环 (AF) 的精确建模是计算机模拟研究脊柱力学的一个重要方面。数值模型需要在微观尺度和器官水平上进行验证才能代表真实系统。尽管 AF 呈现分布式材料属性，但其响应通常使用均匀刚度分布进行建模。本研究的目的是基于片层力学，研究不同建模方法对圆盘模型数值响应的影响。基于单层力学和胶原分布的先前发现，开发了一种材料映射策略来按元素定义局部环带材料属性。比较了三种建模方法：材料属性的均匀分布、径向分布和径向-圆周分布。模拟显示所选择的建模方法对磁盘的组织和器官尺度力学有很大影响。与具有异质材料特性的环形片层的模型相比，具有均匀、平均片层刚度的均质模型预测了显着不同的内应力分布和器官级响应。最后，该研究间接强调，成熟圆盘的组织可能是适应所施加载荷引起的应力的结果，以便将载荷均匀分布在整个结构上。
Accurate modeling of the annulus fibrosus (AF) is a crucial aspect to study spine mechanics in silico. Numerical models require validation at both the microscale and organ level to be representative of the real system. Although the AF presents distributed material properties, its response is often modeled with a homogeneous stiffness distribution. The aim of this study was to investigate the influence of different modeling approaches on the numerical response of disk models, based on lamellae mechanics. A material mapping strategy was developed to define element-wise the local annulus material properties, based on prior findings of single-lamella mechanics and collagen distribution. Three modeling approaches were compared: homogeneous, radial and radial-circumferential distribution of material properties. The simulations showed a strong influence of the chosen modeling approach on the disk's tissue- and organ-scale mechanics. A homogeneous model with uniform, average lamellae stiffness predicted a substantially different internal stress distribution and organ-level response, compared to a model with heterogeneous material properties of the annulus lamellae. Finally, the study has indirectly highlighted that the organization of the mature disks could be a consequence of adaptation to the stresses induced by the applied loads, in order to evenly distribute the load over the entire structure.