微創椎弓根螺釘補強之最佳化分析

Optimization analysis of strenthening invasive pedicle screw

蘇崇瑋(Chung-wei Su)

指導教授 ： 黃俊仁

國立中央大學/工學院/機械工程學系/碩士(2012年)

摘要

在老齡化的社會，脊椎疾病成為人類文明病之一，椎弓根螺釘為進行脊椎手術之基本原件，於手術中鎖入椎骨已提供固定源，使得脊椎系統穩定。隨著脊椎微創手術發展，為了配合導引針進行手術，傳統椎弓根螺釘逐漸被中空椎弓根螺釘取代，幾何形狀上由實心轉變成中空的螺釘。本研究先針對此兩種模型利用ANSYS套裝軟體以有限元素分析法比較應力上之差異；之後，並將同材質之Ti6Al4V插銷置入中空椎弓根螺釘中，進行強度補強之研究，探討此三種椎弓根螺釘(傳統、中空及中空置入插銷)之強度差異性。
此外，針對插銷置入中空孔之椎弓根螺釘模型，搭配田口品質工程法進行最佳化分析，將因子區分為椎弓根螺釘直徑5個水準、中空孔直徑3個水準、插銷間隙3個水準及插銷長度3個水準等四因子，探討各因子對於受力的椎弓根螺釘應力值之貢獻度，並找出模型之最佳化設計，最後進行驗證試驗以確定本研究之田口法使用是否正確。
最後，本研究參考文獻，建構出適用於本研究之微創用椎弓根螺釘之彎曲強度數學模性，並驗證其應力值與經有限元素分析之值是否呈現正相關，日後研究螺釘模型如與本研究相同，可於進行有限元素法之前先以此數學模型進行計算，可節省分析時間。

關鍵字

脊椎微創手術 ； 有限元素分析法 ； 田口品質工程法 ； 椎弓根螺釘

並列摘要

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.

並列關鍵字

Taguchi method ； finite element analysis ； invasive spine surgery ； pedicle screw

參考文獻

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