指導教授：潘永寧臺灣大學：機械工程學研究所林宏銘Lin, Hung-MingHung-MingLin2014-11-292018-06-282014-11-292018-06-282014http://ntur.lib.ntu.edu.tw//handle/246246/263244Surgeons often use spinal fixators to manage spinal instability. Dynamic spinal fixators, such as the Dynesys (DY) and K-ROD (KD) systems, are designed to restore spinal stability and to provide flexibility. The long-term complications of implant breakage and the biomechanics of the adjacent and the bridged levels using KD system are still unknown. In addition, it is important to optimize the dynamic implant stiffness for desired spinal range of motion (ROM) achievement. As first, this study investigates stiffness of KD system and shows the stiffer structure from KD system. Afterwards, this study is to design a new spinal fixator using topology optimization (topology design (TD) system) to reduce the overall stiffness. Also, this study proceeds to investigate and compare the biomechanical effects of DY, KD, and TD system. Here, this study constructed finite element (FE) models of degenerative disc disease (DDD), DY, KD, and TD system. A hybrid-controlled analysis was applied to each of the four FE models. The rod structure of the topology optimization was modeled at a 39% reduced volume compared with the rigid rod. The FE results indicated that KD system supplies the greater stiffness during extension and the lower stiffness during flexion, in contrast to DY system. In contrast to DY system, KD system increased zygapophysial joint force of adjacent level, but this system decreased the cranial adjacent disc and pedicle screw stress during flexion. Additionally, KD and DY systems increased stiffness to within 47% of the value in the DDD model in all motions. As for TD system, it provided the softer rigidly structure during flexion in contrast to KD and DY system and was similar to DY system in terms of rigidly construct during extension, lateral bending, and torsion. TD system reduced the load in cranial adjacent disc and adjacent zygapophysial joint. The implant was burdened with TD system. Hence, topology design system is possible to avoid early adjacent disc and zygapophysial joint degeneration. Nevertheless, in contrast to KD and DY system, the lower load in the pedicle screw of TD system may prolong the life of pedicle screw in fatigue performance.Abstract (Chinese) III Abstract (English) IV Chapter 1: Introduction 1 1.1 Overview 1 1.2 Motivation and Objectives 2 1.3 Outline 2 Chapter 2: Background 4 2.1 Spinal anatomy and behavior 4 2.2 Biomechanics for lumbar spine 20 2.3 Disc degeneration 25 2.4 Computational model 27 2.5 Spinal topological optimized implant 34 2.6 Pedicle screw-based stabilization systems 42 Chapter 3: Material and Method 49 3.1 Validation of the FE model 49 3.2 FE model of DY and KD systems 53 3.3 New design of dynamic spinal fixator using topology optimization 53 3.4 Boundary and loading conditions 61 Chapter 4: Result 62 4.1 K-Rod and Dynesys 62 4.1.1 ROM of lumbar spine 62 4.1.2 Stress of adjacent disc and lumbar spine 62 4.1.3 Facet contact forces 62 4.1.4 Pedicle screw stress 68 4.2 Topology Optimization 68 4.2.1 ROM of lumbar spine 68 4.2.2 Stress on the adjacent disc 71 4.2.3 Facet contact forces 71 4.2.4 Stress on the pedicle screw 76 Chapter 5: Discussion 79 Chapter 6: Conclusion and Future work 89 Reference 93 Curriculum Vitae 1069812851 bytesapplication/pdf論文公開時間：2019/07/29論文使用權限：同意有償授權(權利金給回饋學校)拓樸最佳化有限元素分析脊椎生物力學動態脊椎穩定器DynesysK-ROD[SDGs]SDG3thesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/263244/1/ntu-103-D95522005-1.pdf