| 摘要: |
| 目的 建立USS坚强内固定系统、Isobar TTL半坚强内固定系统的腰椎三维有限元模型,对比两种模型的力学分布特点,探索动态内固定系统对腰椎生物力学的影响,为动态内固定系统临床应用提供理论依据。方法 依据1名正常男性志愿者中立位下螺旋CT扫描资料,利用Mimics 11.1、Geomagic studio 10.0、HyperMesh 10.0和Abaqus 6.8等软件构建L3~S1三维有限元模型,重建Isobar TTL和USS术后模型,对模型施加150 N预载荷及10 Nm力矩,分别记录不同工况下模型的椎间活动度、邻段椎间盘应力及内固定应力分布和应力峰值。结果 成功建立了解剖结构精细的L3～S1三维有限元模型及Isobar TTL和USS术后模型。Isobar TTL和USS模型应力主要分布在螺钉钉身,USS模型应力峰值大于Isobar TTL模型,主要集中在螺钉中部,但均不超过100 MPa；Isobar TTL模型椎间稳定性与正常模型无明显差异,而USS模型的运动范围明显下降,在屈伸工况下最为明显；Isobar TTL模型邻段L3/L4椎间盘应力在前屈、后伸、侧曲、旋转工况下分别增加了6.2%、9.7%、3.6%、3.8%,而USS模型分别增加了8.5%、13.5%、4.3%、4.8%。结论 Isobar TTL系统能有效维持术后腰椎活动度,减少应力遮挡,理论上可以减缓邻近节段的退变。 |
| 关键词: 脊柱 动态内固定 脊柱融合术 有限元分析 |
| DOI：10.3724/SP.J.1008.2013.00416 |
| 投稿时间：2012-12-17修订日期：2013-02-26 |
| 基金项目: |
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| Finite element analysis of Isobar TTL techniques and universal spinal system for lumbar spine: a comparison |
| LIU Jian-hang,JIN An-min*,DUAN Yang,WEM Yong-fu,ZHANG Li |
(Centre of Orthopaedics, Zhujiang Hospital, Southern Medical University, Guangzhou 510282,Guangdong, China
*Corresponding author.) |
| Abstract: |
| Objective To establish finite element models of universal spinal system (USS) and Isobar TTL on L3-S1 with fine anatomical structures and to compare the characteristics of stress distribution of the two models, so as to explore the influence of dynamic internal fixation system (DIFS) on the lumbar biomechanics, providing a theoretical basis for clinical application of DIFS.Methods The lumbar spine geometries were determined using the CT images of a 26-year-old healthy man. The finite element models of USS and Isobar TTL were constructed by using package Mimics 11.1, Geomagic studio 10.0, HyperMesh 10.0 and Abaqus 6.8. The ranges of motion, intervertebral disc stress of adjacent segments, and stress distribution and peak of internal fixation were recorded when the models were subjected to 150 N preload and 10 Nm moment of forces under different conditions: flexion, extension, lateral bending and axial rotation.Results We have successfully constructed the definite element model of L3-S1 with fine anatomical structures and the postoperation models of Isobar TTL and USS. The stress of Isobar TTL and USS model was mainly distributed on the screws, with the maximal stress on USS model being higher than that on the Isobar TTL model. The screws had high stress at the middle part, with the maximal stress being all less than 100 MPa under different conditions. The intervertebral stability of Isobar TTL model was not greatly different from that of normal model; however, the overall motion of USS model was obviously deceased, especially when at flexion and extension condition. For Isobar TTL model, the increases of intervertebral disc stress of adjacent segments of L3/L4 for forward bending, backward extension, lateral bending and rotation were 6.2%, 9.7%, 3.6%, and 3.8%, respectively, and the numbers for USS model were 8.5%, 13.5%, 4.3% and 4.8 %, respectively.Conclusion The maximal stress of Isobar TTL system can effectively maintain the range of motion of the lumbar spine, reduce the resistance of stress, and delay adjacent segment degeneration in theory. |
| Key words: spine dynamic internal fixation spinal fusion finite element analysis |
