Lu Yongtao, Rosenau Eike, Paetzold Helge, Klein Anke, Püschel Klaus, Morlock Michael M, Huber Gerd
Institute of Biomechanics, TUHH Hamburg University of Technology, Hamburg, Germany.
Proc Inst Mech Eng H. 2013 Dec;227(12):1265-74. doi: 10.1177/0954411913501293. Epub 2013 Aug 29.
The probability of fractures of the cortical shell of vertebral bodies increases as ageing progresses. Ageing involves all the spinal component changes. However, the effect of the spinal component ageing on the fracture risk of the cortical shell remains poorly understood. In this study, the influence of the ageing of the spinal components on cortical shell strain was investigated. A lumbar spinal specimen (L3-L5) was mechanically tested under a quasi-static axial compressive load. Clinical computed tomography images of the same specimen were used to create a corresponding finite element model. The material properties were determined by calibrating the finite element model using the L4 cortical shell strains of the anterior centre measurement site. The remaining experiment data (axial displacement, the intra-discal pressures, L4 cortical shell strain on the lateral measurement site) were used to evaluate the model. The individual ageing process of the six spinal components (cortical shell, cancellous bone, bony endplate, posterior elements, nucleus pulposus and annulus matrix) was simulated by changing their Young's moduli and Poisson's ratios, and the effect on cortical shell strain was investigated. Results show that the cortical shell strain is more sensitive to the ageing of the cortical shell and the cancellous bone than to the ageing of the nucleus pulposus, the annulus matrix, and the bony endplates and of the posterior elements. The results can help the clinicians focus on the aspects that mainly influence the vertebral cortex fracture risk factor.
随着年龄的增长，椎体皮质壳骨折的概率会增加。衰老涉及脊柱所有组成部分的变化。然而，脊柱组成部分的衰老对皮质壳骨折风险的影响仍知之甚少。在本研究中，研究了脊柱组成部分的衰老对皮质壳应变的影响。对一个腰椎标本（L3-L5）在准静态轴向压缩载荷下进行力学测试。使用同一标本的临床计算机断层扫描图像创建相应的有限元模型。通过使用前中心测量部位的L4皮质壳应变校准有限元模型来确定材料属性。其余实验数据（轴向位移、椎间盘内压力、外侧测量部位的L4皮质壳应变）用于评估模型。通过改变六个脊柱组成部分（皮质壳、松质骨、骨终板、后部结构、髓核和纤维环基质）的杨氏模量和泊松比来模拟其个体衰老过程，并研究其对皮质壳应变的影响。结果表明，皮质壳应变对皮质壳和松质骨衰老的敏感性高于对髓核、纤维环基质、骨终板和后部结构衰老的敏感性。这些结果可以帮助临床医生关注主要影响椎体皮质骨折风险因素的方面。
