侧脑室角部周围易发脑水肿的生物力学机制有限元分析

Biomechanical mechanism of prominent brain edema around the lateral ventricle horns: A finite element analysis

目的探讨侧脑室角部周围易发脑水肿的生物力学机制。方法依据正常成人颅脑CT图像资料建立侧脑室二维有限元模型,定义脑组织为各向同性固液两相多孔线弹性连续介质,设置生物力学参数和边界条件,运用计算机模拟脑积水发生、发展过程,分析侧脑室周围脑组织的生物力学响应。结果有限元模型直观显示了脑积水发生时侧脑室各部的动态扩张过程,侧脑室周围脑组织产生了不同的生物力学响应,前、后角部周围发生膨胀性应力集中,室管膜拉伸,孔隙比增大,孔隙液压力增高。结论膨胀性应力集中及其所引起的室管膜拉伸、孔隙比增大是侧脑室角部周围易发脑水肿的生物力学机制。

Objective To explore the biomechanical mechanism why brain edema is most prominent around the lateral ventricle horns when hydrocephalus occurs.Methods A two-dimensional finite element model of the lateral ventricle was created based on the CT images of normal cerebra,and brain parenchyma was modeled as a two-phase material composed of a porous elastic matrix saturated by interstitial fluid.Setting the biomechanical parameters and boundary conditions,a computer simulation of hydrocephalus was used to study the biomechanics responses of periventricular brain tissues.Results The results of the finite element simulation intuitively showed the progressive expansion of every part of the ventricle when hydrocephalus occurred.There were heterogeneous biomechanics responses in the periventricular brain tissues.Expansive stress concentrations were found in the brain tissues surrounding the anterior and posterior horns.As a result,the ependyma around the ventricular horns was stretched,the void ratio and the pressure of pore fluid were increased.Conclusions The expansive stress concentration and the stretched ependyma and increased void ratio arising from it are the biomechanical mechanisms of prominent brain edema around the lateral ventricle horns.