A fiber-reinforced composite model of the viscoelastic behavior of the brainstem in shear
A fiber-reinforced composite model of the viscoelastic behavior of the brainstem in shear
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DOI：
10.1016/s0021-9290(99)00042-1
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发表时间：
1999-08-01
影响因子：
2.4
通讯作者：
Margulies, SS
中科院分区：
文献类型：
--
作者：
Arbogast, KB;Margulies, SS
脑干创伤常发生在严重的头部损伤，往往导致致命的损害，由于脑干的重要性，在关键的神经功能。在结构上，脑干由细胞外基质包围的轴索纤维束组成。我们假设，定向结构和架构的脑干决定了这种机械响应，并导致其选择性的脆弱性，在旋转负载。为了了解生物结构和机械响应之间的关系，并提供进一步了解该地区的高度脆弱性，创建了一个结构和数学模型。纤维增强复合材料模型由粘弹性纤维包围的粘弹性基质被用来与脑干的生物结构，其各向异性的机械响应。测量的相关模型参数包括脑干的复合材料的复合模量和基质和纤维的相对分数。该模型预测，纤维组分比基质刚性大三倍，粘性大。将纤维模量预测值与实验组织测量值进行比较。视神经是一束紧密排列的纵向有髓纤维，几乎没有基质，作为脑干纤维成分的替代物。模型预测与实验测量一致，提供了一个验证的模型。这种方法提供了一个特定的生物结构的脑干和各向异性的机械响应之间的关系的理解，并允许洞察旋转头部损伤的选择性脆弱性，该地区的原因。(C)1999 Elsevier Science Ltd.保留所有权利。
Brainstem trauma occurs frequently in severe head injury, often resulting in fatal lesions due to importance of brainstem in crucial neural functions. Structurally, the brainstem is composed of bundles of axonal fibers distinctly oriented in a longitudinal direction surrounded by an extracellular matrix. We hypothesize that the oriented structure and architecture of the brainstem dictates this mechanical response and results in its selective vulnerability in rotational loading. In order to understand the relationship between the biologic architecture and the mechanical response and provide further insight into the high vulnerability of this region, a structural and mathematical model was created. A fiber-reinforced composite model composed of viscoelastic fibers surrounded by a viscoelastic matrix was used to relate the biological architecture of the brainstem to its anisotropic mechanical response. Relevant model parameters measured include the brainstem's composite complex moduli and relative fraction of matrix and fiber. The model predicted that the fiber component is three times stiffer and more Viscous than the matrix. The fiber modulus predictions were compared with experimental tissue measurements. The optic nerve, a bundle of tightly packed longitudinally arranged myelinated fibers with little matrix, served as a surrogate for the brainstem fiber component. Model predictions agreed with experimental measures, offering a validation of the model. This approach provided an understanding of the relationship between the specific biologic architecture of the brainstem and the anisotropic mechanical response and allowed insight into reasons for the selective vulnerability of this region in rotational head injury. (C) 1999 Elsevier Science Ltd. All rights reserved.