Si-Hoe K M, Teoh S H, Teo Jeremy
J Biomech Eng. 2006 Dec;128(6):957-64. doi: 10.1115/1.2375136.
To date, no apparatus has yet been devised which would allow the study of bone microstructure of the whole vertebrae under mechanical loading. This paper outlines the design and development of a 3-axis radio-translucent mechanical testing rig for spinal research and testing. This rig is to be used in conjunction with a Shimadzu micro-CT scanner. Several tests were conducted to verify the feasibility of the rig design. First, the maximum range of deformation in compression, flexion\extension, and lateral bending that could be exerted on a goat lumbar functional spinal unit was evaluated using the noncontact digital markers method. Stepwise compression loading was also conducted on a single porcine vertebra and the loading data was compared to results obtained from an industrial grade compression testing machine. Finally, micro-CT scans of a porcine vertebra prior to and at a compression failure strain were obtained. The rig was confirmed to be able to exert pure moment loading in the above mentioned modes of deformation and the extent of deformation was comparable to previous documented results. The stepwise compression loading conducted in the rig was also found to effectively approximate a continuous loading of the same specimen in an industrial grade compression testing machine. Finally, resultant micro-CT images of isotropic resolution 32.80 mum of a porcine vertebra loaded in the rig were obtained. For the first time, trabecular microarchitecture detail of a whole vertebra buckling under 12.1% failure compression strain loading was studied using voxel-data visualization software. These initial series of tests verify the feasibility of the rig as an apparatus incorporating spinal testing and imaging.
迄今为止，尚未设计出一种能够在机械加载条件下对整个椎骨的骨微结构进行研究的仪器。本文概述了一种用于脊柱研究和测试的三轴射线可穿透机械测试装置的设计与开发。该装置将与岛津微计算机断层扫描仪配合使用。进行了多项测试以验证该装置设计的可行性。首先，使用非接触式数字标记方法评估了可施加在山羊腰椎功能脊柱单元上的压缩、屈伸和侧弯的最大变形范围。还对单个猪椎骨进行了逐步压缩加载，并将加载数据与从工业级压缩试验机获得的结果进行了比较。最后，获取了猪椎骨在压缩破坏应变之前和之时的微计算机断层扫描图像。结果证实，该装置能够在上述变形模式下施加纯弯矩载荷，并且变形程度与先前记录的结果相当。还发现该装置中进行的逐步压缩加载有效地近似于在工业级压缩试验机中对同一试样的连续加载。最后，获得了在该装置中加载的猪椎骨的各向同性分辨率为32.80微米的微计算机断层扫描图像。首次使用体素数据可视化软件研究了在12.1%破坏压缩应变载荷下整个椎骨屈曲时的小梁微结构细节。这些初步的一系列测试验证了该装置作为一种结合脊柱测试和成像功能的仪器的可行性。
