Inter-lamellar shear resistance confers compressive stiffness in the intervertebral disc: An image-based modelling study on the bovine caudal disc
Inter-lamellar shear resistance confers compressive stiffness in the intervertebral disc: An image-based modelling study on the bovine caudal disc
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DOI：
10.1016/j.jbiomech.2015.10.041
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发表时间：
2015-12-16
影响因子：
2.4
通讯作者：
Skalli, Wafa
中科院分区：
文献类型：
--
作者：
Adam, Clayton;Rouch, Philippe;Skalli, Wafa
椎间盘承受大的压缩负荷（高达人体体重的九倍），同时为脊柱提供灵活性。在显微结构水平上，椎间盘的外鞘（纤维环）包括12-20个嵌入软基质中的交替交叉胶原纤维的环形层。椎间盘的中心（髓核）由富含蛋白多糖的水合凝胶组成。椎间盘是人体内最大的无血管结构，由于椎间盘退变和背痛的高社会负担，在生物力学方面备受关注。虽然在整个关节尺度上对椎间盘进行了很好的表征，但尚不清楚椎间盘组织的微观结构如何赋予其整体机械性能。特别是，关于纤维环中相邻椎板之间的连接水平存在相互矛盾的报告，这些界面对椎间盘整体完整性的重要性尚不清楚。我们使用了偏振光显微照片的牛尾盘的横截面，开发一个基于图像的有限元模型，将滑动和分离层之间的环，并进行轴向压缩载荷的模型。还在4个牛尾椎间盘上进行了验证实验。层间剪切阻力有很大的影响，光盘压缩刚度，与40%的刚度下降时，界面剪切阻力从完全粘结到自由滑动。相比之下，层间内聚力对整个椎间盘力学没有明显的影响。我们的结论是，层间的剪切阻力赋予光盘的机械阻力压缩，层间界面结构的退化可能是一个前兆宏观椎间盘退变。(C)2015爱思唯尔有限公司版权所有。
The intervertebral disc withstands large compressive loads (up to nine times bodyweight in humans) while providing flexibility to the spinal column. At a microstructural level, the outer sheath of the disc (the annulus fibrosus) comprises 12-20 annular layers of alternately crisscrossed collagen fibres embedded in a soft ground matrix. The centre of the disc (the nucleus pulposus) consists of a hydrated gel rich in proteoglycans. The disc is the largest avascular structure in the body and is of much interest biomechanically due to the high societal burden of disc degeneration and back pain. Although the disc has been well characterized at the whole joint scale, it is not clear how the disc tissue microstructure confers its overall mechanical properties. In particular, there have been conflicting reports regarding the level of attachment between adjacent lamellae in the annulus, and the importance of these interfaces to the overall integrity of the disc is unknown. We used a polarized light micrograph of the bovine tail disc in transverse cross-section to develop an image-based finite element model incorporating sliding and separation between layers of the annulus, and subjected the model to axial compressive loading. Validation experiments were also performed on four bovine caudal discs. Interlamellar shear resistance had a strong effect on disc compressive stiffness, with a 40% drop in stiffness when the interface shear resistance was changed from fully bonded to freely sliding. By contrast, interlamellar cohesion had no appreciable effect on overall disc mechanics. We conclude that shear resistance between lamellae confers disc mechanical resistance to compression, and degradation of the interlamellar interface structure may be a precursor to macroscopic disc degeneration. (C) 2015 Elsevier Ltd. All rights reserved.