| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 103 === Posterior lumbar interbody fusion (PLIF) has been the most commonly used surgical method for treating damaged disc which caused by human aging、long-term bad posture or external force. But many clinical studies have showed that adjacent segment degeneration was found during the tracking observation period. In recent years, due to the flourishing development of 3D printing technology, this study will focus on the design of cage which included the shape optimum design、material selection and porous design. Each cage design will also do some simulation comparison with different posterior fixation systems. However, no research investigated on the cage design for spine motion and adjacent segment. 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).
A 3-D nonlinear finite element model of the T10-S1 spine with cage and posterior fixation system were developed in this study. To simulate the bone fusion surgery, the cage was inserted into the L3-L4. The loading cases of flexion、extension、lateral bending and axial rotation were considered. In post-processing, intersegmental rotation、disc stress and pedicle screw stress were calculated at implant level and adjacent level.
The results showed that all Ti alloy and no porous cage with rigid fixation system can achieve good stability. However, it will also increase the risk of adjacent segment degeneration and pedicle screw breakage. Relatively, the intersegmental rotation and disc stress of the composite materials (25%Ti-75%PEEK) and high porosity cage with Dynesys dynamic fixation system are very close to intact spine situation. Finally, this study could help surgeons to understand the biomechanical performances of additive manufactured cages.
|
|---|
