Biomechanical modelling of normal pressure hydrocephalus
Biomechanical modelling of normal pressure hydrocephalus
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DOI：
10.1016/j.jbiomech.2008.04.014
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发表时间：
2008-07-19
影响因子：
2.4
通讯作者：
Miller, Karol
中科院分区：
文献类型：
--
作者：
Dutta-Roy, Tonmoy;Wittek, Adam;Miller, Karol
本研究采用计算方法研究正常压力脑积水（NPH）生长的机制。我们创建了一个健康人脑的通用三维脑网格，并将脑实质建模为单相和双相连续体。在我们的模型中，超弹性本构关系和有限变形理论描述了脑实质内的变形。我们使用155.77 Pa的值作为脑实质的剪切模量（p）。此外，在我们的模型中，接触边界定义将大脑外表面限制在颅骨内。我们使用跨地幔压差加载模型。完全非线性，隐式有限元程序在时域中被用来获得脑室和大脑的变形。据我们所知，这是第一个3D。研究NPH生长机理的完全非线性模型。临床医生普遍认为，最多1 mm Hg跨膜压差（133.416 Pa）与NPH的状况相关。我们的计算表明，transmantle压力差为1毫米的Ha（133.416帕）没有产生NPH的单相或双相模型的脑实质。产生NPH的临床状况所需的最小跨膜压差为1.764 mm Hg（235.44 Pa）。这表明NPH生长的纯机械基础的假设需要修改。我们还表明，在等transmantle压差负荷下，脑实质的两相和不可压缩/几乎不可压缩单相模型的计算心室容积之间没有显著差异。因此，使用脑实质的双相模型没有获得重大优势。我们建议，NPH建模，几乎不可压缩的单相模型的脑实质是足够的。脑实质的单相处理简化了NPH模型的数学描述，并导致计算约束的显著减少。(C)2008爱思唯尔有限公司保留所有权利。
This study investigates the mechanics of normal Pressure hydrocephalus (NPH) growth using a computational approach. We created a generic 3-D brain mesh of a healthy human brain and modelled the brain parenchyma as single phase and biphasic continuum. In Our model, hyperelastic constitutive law and finite deformation theory described deformations within the brain parenchyma. We used a value of 155.77 Pa for the shear Modulus (p) of the brain parenchyma. Additionally, in our model, contact boundary definitions constrained the brain outer surface inside the skull. We used transmantle pressure difference to load the model. Fully nonlinear, implicit finite element procedures in the time domain were used to obtain the deformations of the ventricles and the brain. To the best Of Our knowledge, this was the first 3-D. fully nonlinear model investigating NPH growth mechanics. Clinicians generally accept that at most 1 mm of Hg transmantle pressure difference (133.416 Pa) is associated with the condition of NPH. Our computations showed that transmantle pressure difference of 1 mm of Ha (133.416 Pa) did not produce NPH for either single phase or biphasic model of the brain parenchyma. A minimum transmantle pressure difference of 1.764 mm of Hg (235.44 Pa) was required to produce the clinical condition of NPH. This suggested that the hypothesis of a purely mechanical basis For NPH growth needs to be revised. We also showed that under equal transmantle pressure difference load, there were no significant differences between the computed ventricular volumes for biphasic and incompressible/nearly incompressible single phase model of the brain parenchyma. As a result, there was no major advantage gained by using a biphasic model for the brain parenchyma. We propose that for modelling NPH, nearly incompressible single phase model of the brain parenchyma was adequate. Single phase treatment of the brain parenchyma simplified the mathematical description of the NPH model and resulted in significant reduction of computational tie. (C) 2008 Elsevier Ltd. All rights reserved.