Study on the piezoelectric properties of cancellous bone

该研究项目与髋关节电刺激内假体的开发密切相关。然而，这些结果的意义要广泛得多。随着人口老龄化的日益加剧，翻修手术可能越来越有必要。通常情况下，在人工假体的附近会发现大量的骨损伤。这种骨骼损伤也可能是由疾病(如骨癌、酗酒造成的损伤)或意外造成的。在之前的工作中，与骨科同事密切合作，开发了用于电刺激髋关节置换的电极系统的第一个设计。虽然电刺激促进骨生长的方法原则上已经知道并实现了近40年，但关于其基本作用机制，许多问题仍然悬而未决。此外，临床证明经验刺激参数是有效的，但尚不清楚这些参数是否是最佳参数，以及它们与生理过程的确切关系。因此，本项目的目标是准确地研究骨组织的压电行为，并指定合适的压电组织参数。在这里，将使用Fukada和Yasuda的实验测试装置，他们是1957年第一个通过实验证明骨骼的压电性的人，这些实验也将在硅胶中重现。在模拟中，进行了广泛的参数研究。所得到的组织参数应用于其他项目，以优化先前经验性的刺激参数。

The research project is closely linked with the development of electro-stimulative endoprostheses for the hip joint. The results, however, have a much broader meaning. With a growing aging population, increasingly, revision surgery may be necessary. Often large bone damage is found in the immediate vicinity of the endoprosthesis. Such bone damage may also be caused by disease (eg, bone cancer, damages from alcohol abuse) or accident. In previous work, working closely with colleagues from orthopedics, a first design of an electrode system for a electro-stimulative hip replacement was developed. Although in principle the method of electrical stimulation to enhance bone growth has been known and attained for nearly four decades, many questions still remain open regarding the basic mechanism of action. Furthermore, the empirical stimulation parameters clinically showed to be effective, but it remains unclear whether these are the optimal parameters and how they are exactly related to the physiological processes. Therefore, the goal of this project is to accurately investigate the piezoelectric behavior of bone tissue and to specify appropriate piezoelectric tissue parameters. Here, an experimental test set-up of Fukada and Yasuda, who were the first in 1957 to demonstrate the piezoelectric properties of bone experimentally, will be used and the experiments are reproduced in silico as well. In the simulations, extensive parametric studies are carried out. The resulting tissue parameters should be used in other projects in order to optimize the stimulation parameters previously empirically.