使用有限元法分析椎弓根螺絲系統的幾何設計和負載因素之參數研究

Parametric study of geometrical and loading factors for designing implants using finite element analysis

哈尼(Hani Fakhry Hassan Eisawy)

指導教授 ： 鄒年棣

國立交通大學/工學院/材料科學與工程系所/碩士(2020年)

摘要

脊椎骨折不僅是老年人的普遍問題，也同樣影響勞力高度密集以及需要久坐在電腦前等工作類型之年輕人。近年來，椎弓根螺絲系統 (pedicle screw system)被用在治療此一問題，並可進一步實現改善患者生活品質。然而，椎弓根釘之骨整合程度取決於周圍骨頭的性質。椎弓根螺絲系統的治療腔體 (Healing chamber)以及負載條件是兩個影響骨頭性質之主要因素，因此本文將深入探討其對骨頭性質之影響。本研究使用有限元素法模擬六根椎弓根螺絲系統於脊椎骨L3~L5在不同的負載條件下之骨頭性質。首先，本實驗透過ANSYS Workbench軟體設計、並計算周圍骨頭應變以評估不同幾何形狀之治療腔體骨癒合效能。除此之外，本研究更進一步利用MATLAB以及ANSYS APDL開發細胞分化演算法，以預測骨癒合形貌。此演算法不僅有助於我們了解癒合期間的骨形成歷程，更幫助我們評估了癒合腔室設計以及負荷條件對骨頭性質的影響。

關鍵字

脊椎骨折 ； 細胞分化 ； 骨癒合 ； 有限元法

並列摘要

Vertebral fractures become among the common problems not only for elderly people but also for the younger people who do both kinds of jobs that involve the muscular and physical activities, and the other kinds which require sitting for longtime in front of the computer. One of the ways for the treatment of this serious problem is the implanting of the pedicle screw system. pedicle screw system is required to be well fixed for achieving a successful treatment and to improve the quality of living for the patients. The well fixation of the pedicle screw system is controlled by bone quality during the healing period which is affected by many factors. The screw healing chamber design and loading conditions are considered as main factors that affect the bone quality, and their effects on the bone quality are well studied in this thesis.
The study starts with simulating the implementation of 6 pedicle screws in L3, L4 and L5 using finite element method to understand the loading condition which could lead us to setup the boundary conditions for one screw bone system. Many healing chambers were designed and evaluated using ANSYS WB by checking if the bone surrounding the pedicle screw is in the healthy strain region. An algorithm based on cell differentiation and mechano-regulation is developed by MATLAB and ANSYS APDL to be used for predicting the quality of the bone along the healing period. These results help us to understand the bone formation along the healing period. Also, the algorithm helped us to evaluate the effect of each healing chamber design on the bone formation quality along the healing period. Another side from our research is to understand more about the effect of different loading conditions on the bone formation quality along the healing period.

並列關鍵字

Vertebral fractures ； cell differentiation ； biomechanics ； healing chamber ； mechano-regulation ； Finite element method ； implant design

參考文獻

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