Biomechanical Investigation of Pedicle Screw System for the Treatment of Lumbar Degenerative Disc Disease

• Main Authors: Shu-yu Jhou, 周姝妤
• Other Authors: Ching-Kong Chao
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/39983093134800021227

碩士 === 國立臺灣科技大學 === 機械工程系 === 101 === Fusion has been the gold standard treatment for treating the disc degeneration. Many clinical studies have showed that adjacent segment degeneration was observed in patients over time. In order to overcome problems with fusion devices, dynamic stabilization systems are being used to treat disc degeneration related problems. Recently it’s began to combine fusion and non-fusion techniques in the treatment of multi-segmental Degenerative disc disease (DDD). It is hybrid dynamic stabilization designed to promote a balance of stability and adjacent segment degeneration. However, no report investigated whole spine motion and the segment adjacent to the hybrid dynamic stabilization. The purpose of this study was to investigate how different treatment methods influence the biomechanics of adjacent segment and which one is the best treatment of hybrid dynamic stabilization. A 3-D nonlinear finite element model of the T11-S1 lumbar spine was used to evaluate biomechanics of various device including rigid rod, semi-rigid rod, Dynesys and hybrid stabilization systems inserted at level L4/L5 in comparison with intact spine. Mild disc degeneration was simulated at L4-L5 level. The loading cases of flexion, extension, lateral bending and axial rotation were simulated. Intersegmetal rotation, disc stresses and screw stresses were calculated at implant level and at the adjacent level. Compared to an intact spine, a dynamic implant reduced inter-segmental rotation at implant level, decreased disc stresses and at implant level. With a rigid implant, these effects are more pronounced. Screw stresses were generally higher in a rigid fixator than in a dynamic implant. The rigid implant had more effect than dynamic implant at the adjacent level. With the hybrid stabilization systems, our results indicated that where the dynamic implant placed superior to the rigid fixator inserted at degenerative disc level was the better treatment.