有限元分析皮质骨轨迹螺钉联合椎弓根螺钉固定椎体运动单元的 生物力学性能. (Chinese)

BACKGROUND: The biomechanical research on a single cortical bone track screw has been reported in many articles at home and abroad. There are not many reports on the biomechanical research on the entire motion unit of the vertebral body, cage, and screw rod, especially the stress distribution of the motor unit and the stability of the internal fixation device by the fixation method of cortical bone trajectory combined with pedicle screw. OBJECTIVE: To summarize and analyze the biomechanical differences between traditional pedicle screw fixation and cortical bone trajectory combined with pedicle screw fixation in osteoporotic vertebral bodies. METHODS: The CT scan data of one osteoporosis volunteer (bone mineral density T value < -0.25 SD) were obtained, and the L 3 -S 1 vertebral functional unit osteoporosis finite element model was established to simulate the fixation of traditional trajectory screws and cortical bone trajectory combined with pedicle screws after verification of validity. The stress distribution and stability of the two internal fixation methods on the motion unit were compared according to the force and activity of the vertebral body motion unit in the flexion, extension, lateral flexion and rotation states, respectively. RESULTS AND CONCLUSION: (1) The results of finite element verification showed that the model could well simulate the physiological activity of lumbar vertebrae in osteoporosis patients. (2) In the flexion and extension states, the maximum stress of the internal fixator was similar to that of the traditional trajectory screw group, but the maximum stress of the nail rod system in the cortical bone trajectory combined with pedicle screw group was greater than that in the traditional trajectory screw group in the lateral flexion and rotation states. In lateral flexion, the cortical bone trajectory combined with pedicle screw group increased by 11.5% compared with traditional trajectory screw group, and in rotation, the cortical bone trajectory combined with pedicle screw group increased by 25.2% compared with traditional trajectory screw group. The maximum equivalent stress of cage in cortical bone trajectory combined with pedicle screw group was greater than that in traditional trajectory screw group, and the maximum equivalent stress of cage in cortical bone trajectory combined with pedicle screw group was 17% higher than that in traditional trajectory screw group during lateral flexion and 15% higher than that in rotation. (3) Two groups of model after in static load, bending forward, stretch, lateral flexion and rotation condition, intervertebral range of motion, two kinds of internal fixation devices can provide similar stability. (4) In general, both fixation methods can enhance the fixation strength of the lumbar fusion segment and provide similar stability, but cortical bone trajectory combined with pedicle screw internal fixation can further enhance the mechanical strength of the fusion segment and provide a better fusion stress environment. [ABSTRACT FROM AUTHOR]

背景: 关于单个皮质骨轨迹螺钉的生物力学研究国内外已有多篇文章报道, 但关于椎体、融合器、钉棒整个运动单元的生物力学研究, 特 别是关于皮质骨轨迹螺钉联合传统椎弓根螺钉(cortical bone trajectory combined with pedicle screw, CBTPS)固定方式对运动单元的应力分布 情况及内固定装置稳定性的相关研究报道并不多. 目的: 归纳分析传统椎弓根螺钉固定与CBTPS固定骨质疏松椎体运动单元上的生物力学差异. 方法: 基于一位骨质疏松志愿者(骨密度T值< -0.25 SD)的CT数据, 建立L 3 到骶椎椎体功能单元骨质疏松有限元模型. 通过有效性验证后, 建立传统椎弓根螺钉和CBTPS两种固定模型, 比较两种模型在前屈、后伸、左右侧屈、左右旋转6种工况下内固定的应力及椎体运动单元活 动情况; 比较两种内固定方式下运动单元的应力分布情况及内固定装置的稳定性. 结果与结论: ①有限元验证结果显示, 模型可较好地模拟骨质疏松患者腰椎的生理活动. ②两组模型在屈曲、后伸状态下, 内固定装置最 大应力接近, 但是CBTPS组内固定装置在侧屈与旋转状态下钉棒系统最大应力值要大于传统椎弓根螺钉组, 其中侧屈时, CBTPS组较传统 椎弓根螺钉组增加了11.5%, 在旋转时, CBTPS组较传统椎弓根螺钉组增加了25.2%. CBTPS组cage的应力均大于传统椎弓根螺钉组, 其中侧 屈时, CBTPS组较传统椎弓根螺钉组增加了17%, 在旋转时, CBTPS组较传统椎弓根螺钉组增加了15%. ③两组模型在静载、前屈、后伸、 侧屈、旋转状态下, 椎间活动度相当, 两种内固定装置能提供相似的稳定性. ④总得来说, 两种固定方式均可加强腰椎融合节段的固定强 度, 提供类似的节段稳定性, 但CBTPS内固定方式可进一步加强融合节段的力学强度, 提供更好的融合应力环境. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)