Biomechanical Study on the Fixation Stability of Vertebral Plates with Variable-Angle Screws for Anterior Lumbar Interbody Fusion
| Autor: | Kai-Ju Cheng, 鄭凱如 |
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| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 Spinal disc degeneration or lumbar nerve root compression can be treated by surgical operations. One of surgical operations is anterior lumbar interbody fusion (ALIF). In this surgical procedure, the lumbar disc is incised and removed. Then, an intervertebral cage or a small block of bone graft is placed between the vertebrae. Finally, an anterior vertebral plate is held in front of lumbar vertebrae by bone screws. However, the clinical complications of anterior lumbar vertebral plate system still occur. The fixation stability of anterior vertebral plates might be affected by different screw orientation. Past studies have tried to improve this clinical performance by changing the screw orientation, but their conclusions are inconsistency. Thus, the purpose of this study was to investigate the fixation stability of vertebral plate with variable-angle screws for the anterior lumbar interbody fusion surgery. Three-dimensional solid models of the spinal implants were developed by using SolidWorks, and the nonlinear finite element models were developed to investigate the fixation stability by using ANSYS Workbench. The parametric study and the optimization study of anterior vertebral plate systems were conducted by using Taguchi robust design methods and neurogenetic algorithms, respectively. The results of the numerical studies were validated using the biomechanical tests. For the parameteric study, the consequence of this research was that the contribution of sagittal plane (SI plane) was more influential than transverse plane (ML plane), and L5SI was particularly important design parameter. For the optimal study, optimum design obtained from neurogenetic algorithms was superior to that obtained from Taguchi Methods. The optimum design obtained from neurogenetic algorithms was 15°in SI plane of L4 vertebra, 15° in ML plane of L4 vertebra, -8.2° in SI plane of L5 vertebra, and 15°in ML plane of L5 vertebra. For the biomechanical tests, the numerical results could be validated and the correlation coefficient between the numerical models and the experimental tests was 0.909. The results of this study could directly provide the surgical suggestion and biomechanical rationale to orthopedic surgeons. In addition, those numerical models could also be used to evaluate a new design of anterior vertebral plate. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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