| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 104 === Posterior lumbar interbody fusion (PLIF) has been the most commonly used surgical method for treating degenerative disc which caused by human aging, long-term bad posture or abnormal external force. But many clinical studies have showed that adjacent segment degeneration was found during the postoperative period. The purpose of this study was to find the best implant design which can maintain stabilizing effect and provide good postoperative activity for patients using finite element analysis (FEM).
Three-dimensional finite element models of the T10-S1 spine with cage of different geometric parameters were developed in this study and investigate the parametric analysis, composite materials design and hybrid design of cage. To simulate the bone fusion surgery, the cage was inserted into the L3-L4. The loading cases of flexion, extension, lateral bending and torsion were considered. In post-processing, the intersegmental rotation, the von Mises stress of cage and the von Mises stress of intervertebral disc and cortical bone were calculated at index levels and adjacent levels. Then we consider the correlation between numerical simulation and the mechanical experiment data from Biomedical Technology and Device Research Laboratories of Industrial Technology Research Institute (ITRI_BDL ).
"Micro-structural pillar diameter" and "micro-structural pillar density" significantly affect the intersegmental rotation by the numerical simulation and the mechanical test. However, "micro-structural pillar angle" and "the thickness of the PEEK layer" had no influence. Cage avoids being slender, narrow and scattered geometry. In addition, adding the PEEK layer to the micro-structure is not a good choice to prevent stress of the cage getting higher value. In order to get the best intersegmental rotation and the von Mises stress of cage, we mix two appropriate micro-structures from parametric analysis in hybrid design. Consequently, the 0.4 mm of the pillar diameter, the 55°of the pillar angle and the dense pillar density is the best design.
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