Gong He, Zhang Ming, Qin Ling, Hou Yajun
Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
Ann Biomed Eng. 2007 Sep;35(9):1622-31. doi: 10.1007/s10439-007-9332-8. Epub 2007 May 26.
The aim of this study was to obtain the apparent and tissue-level mechanical parameters of vertebral cancellous bones using micro-finite element analysis, and to identify the regional variations and their relative differences with respect to aging. Ninety trabecular specimens were obtained from six normal L4 vertebral bodies of six male cadavers in two age groups, three aged 62 years and three aged 69 years, and then were scanned using a high-resolution micro-Computed Tomography (micro-CT) system. The obtained micro-CT reconstruction models were then converted to micro-finite element models. Micro-finite element analyses were done to determine the apparent Young's moduli and tissue-level Von Mises stress distribution for each trabecular specimen on the longitudinal direction, and medial-lateral and anterior-posterior directions (transverse directions), respectively. Regional variations about the mechanical parameters at both apparent and tissue levels in different transverse layers and vertical columns within and between the two age groups were then analyzed. The results showed significant decreases in the apparent Young's moduli in each direction with aging, and those in the two transverse directions decreased more with aging compared with the longitudinal direction. Furthermore, there were no statistically significant differences between the mechanical parameters in the two transverse directions in both age groups. This study offered an insight into the distributions and variations of mechanical properties within a vertebral body. The mechanical parameters calculated from this study may help in a better understanding of regional fracture risks and the vertebral fracture mechanism in the prevention of osteoporotic fracture in elder individuals.
本研究的目的是通过微观有限元分析获得椎体松质骨的表观力学参数和组织水平力学参数，并确定其随年龄增长的区域差异及其相对差异。从两个年龄组的六具男性尸体的六个正常L4椎体中获取了90个小梁标本，其中三个年龄为62岁，三个年龄为69岁，然后使用高分辨率微型计算机断层扫描（micro-CT）系统进行扫描。然后将获得的micro-CT重建模型转换为微观有限元模型。进行微观有限元分析，以分别确定每个小梁标本在纵向、内外侧和前后方向（横向）上的表观杨氏模量和组织水平的冯·米塞斯应力分布。然后分析了两个年龄组内和组间不同横向层和垂直柱在表观和组织水平上力学参数的区域差异。结果表明，随着年龄增长，各方向的表观杨氏模量均显著降低，且两个横向方向的降低幅度比纵向方向更大。此外，两个年龄组在两个横向方向上的力学参数之间没有统计学上的显著差异。本研究深入了解了椎体内力学性能的分布和变化。本研究计算得到的力学参数可能有助于更好地理解老年个体骨质疏松性骨折预防中的区域骨折风险和椎体骨折机制。
