Optimization analysis of strenthening invasive pedicle screw

• Main Authors: Chung-wei Su, 蘇崇瑋
• Other Authors: Jiun-Ren Huang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/74164285715806385906

碩士 === 國立中央大學 === 機械工程研究所 === 100 === In this aging society, spinal disease becomes one of the common human civilization diseases. Pedicle screw is a fundamental part used in spinal surgery. We lock pedicle screw into the vertebrae to provide a fixed force to offer the stability of the human spine. With the development of the invasive spine surgery, traditional pedicle screw is replaced by cannular pedicle screw in order to be used in surgery with guide pin. In this study, firstly, we use the finite elements analysis method to compare the two models’ (tradional and cannular) difference in stress. Secondly, we put the same material (Ti6Al4V) of pin into the cannular pedicle screw to expect increasing pedicle screw’s intensity. And compare these three pedicle screws’ (traditional, cannular and cannular with pin) intensity in stress. In addition, we use Taguchi method to do the optimization aimed at cannular pedicle screw with pin. The four factors include five levels of pedicle screw diameter, three levels of cannular diameter, three levels of clearance between pin and cannular pedicle screw and three levels of pin length. Explore the contribution of each factor for pedicle screw’s stress and find out the best model. At last, making the best model, and comparing it with other models to check the Taguchi method we use is correct. At the last, consulting the reference to construct a mathematical model of bending strength of invasive pedicle screw, and compare its stress value with value of FEM. If it shows the positive correlation, we can use this model to calculate stress value before FEM to save analysis time in the fusture.