Dickerson D A, Sander E A, Nauman E A
Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA.
Biomech Model Mechanobiol. 2008 Jun;7(3):191-202. doi: 10.1007/s10237-007-0085-y. Epub 2007 May 23.
Osteoporosis affects nearly 10 million individuals in the United States. Conventional treatments include anti-resorptive drug therapies, but recently, it has been demonstrated that delivering a low magnitude, dynamic stimulus via whole body vibration can have an osteogenic effect without the need for large magnitude strain stimulus. Vibration of the vertebral body induces a range of stimuli that may account for the anabolic response including low magnitude strains, interfacial shear stress due to marrow movement, and blood transport. In order to evaluate the relative importance of these stimuli, we integrated a microstructural model of vertebral cancellous bone with a mixture theory model of the vertebral body. The predicted shear stresses on the surfaces of the trabeculae during vibratory loading are in the range of values considered to be stimulatory and increase with increasing solid volume fraction. Peak volumetric blood flow rates also varied with strain amplitude and frequency, but exhibited little dependence on solid volume fraction. These results suggest that fluid shear stress governs the response of the vertebrae to whole body vibration and that the marrow viscosity is a critical parameter which modulates the shear stress.
在美国，骨质疏松症影响着近1000万人。传统治疗方法包括抗吸收药物疗法，但最近有研究表明，通过全身振动施加低强度的动态刺激可以产生成骨作用，而无需高强度的应变刺激。椎体振动会引发一系列刺激，这些刺激可能是合成代谢反应的原因，包括低强度应变、骨髓运动引起的界面剪切应力以及血液运输。为了评估这些刺激的相对重要性，我们将椎体松质骨的微观结构模型与椎体的混合理论模型相结合。振动加载过程中骨小梁表面预测的剪切应力处于被认为具有刺激作用的值范围内，并随着固体体积分数的增加而增加。峰值体积血流速率也随应变幅度和频率而变化，但对固体体积分数的依赖性较小。这些结果表明，流体剪切应力控制着椎体对全身振动的反应，并且骨髓粘度是调节剪切应力的关键参数。
