A Biomechanical Study of Spinal Motion Segment Based on a Three-Dimensional Nonlinear Poroelastic Finite Element Method
| Autor: | Hsiao-Che Lin, 林孝哲 |
|---|---|
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 97 Clarifying the mechanical behaviors of spinal motion segments (SMSs) will provide guidance in clinical diagnosis and treatment. Therefore, understanding the micro-mechanical behaviors in the SMSs is extremely important. However, information obtained through in vitro experiments of SMSs is limited. In the last ten years, most solid finite element models adopted linear or non-linear analyses to study the mechanical behaviors of SMSs. However, these studies did not consider fluid effects. Furthermore, the obtained deformed shape of an intervertebral disc (IVD) is unrealistic. Conversely, applying porous medium theory and simulating SMSs with the finite element model can accurately describe the bi-phasic interaction effects of solids and fluids in SMSs, and also account for variations in skeletal stress, fluid pressure and fluid fields. As is known, the fluid in the solid skeleton is highly incompressible, and the amount of fluid plays an important role in support of the overall mechanical response of SMSs. To compare with existing in vitro experimental data, and verify the significance of this study, a novel three-dimensional fine poroelastic finite element model was employed, and a geometrically nonlinear process was used to investigate the mechanical behaviors of SMSs. To account for the difference in fluid content of the nucleus and annulus of SMSs in in vitro experiments, the fluid content in the nucleus and annulus are used as variable parameters, and the exterior boundary of the poroelastic media is set as impermissible to fluid flowing out. External force inclines following with the acting surface. The material properties of a porous medium in various tissues are derived from experimental data fitting. The result of this study shows that fluid in the IVD has a very important role in supporting SMSs. The deformation of the IVD is significantly close to that represented by experimental data in literature. The solid stress inside the nucleus remains very low. When fluid content in an IVD decreases, vertical deflection, lateral bulge, and stress in the annulus increase, with swelling pressure of nucleus pulposus reducing. The process introduced here can simulate the real mechanical behavior of SMSs; thus, this study is very useful in understanding the mechanical behavior of SMSs, and provides correct reference information for medicine field. A future study will intensively investigate the in vivo mechanical behavior of SMSs. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|