融合器放置位置对脊柱单侧固定应力分布影响的有限元分析  

Effects of cage placement on unilateral fixed stress distribution in spine： a finite element analysis

作　　者：林斌[1] 陈志达[1] 姚小涛[1] 陆成武 蔡弢艺[1] 吴松松[1] Lin Bin;Chen Zhida;Yao Xiaotao;Lu Chengwu;Cai Taoyi;Wu Songsong(Orthopaedics Center of PLA,The 175th Hospital of PLA,the Affiliated Southeast Hospital of Xiamen University,Zhangzhou,Fujian 363000,China)

机构地区：[1]解放军第一七五医院(厦门大学附属东南医院)全军骨科中心,福建漳州363000

出　　处：《中华生物医学工程杂志》2017年第5期374-379,共6页Chinese Journal of Biomedical Engineering

基　　金：南京军区医学科技创新重点课题（12224）

摘　　要：目的建立L4～L5节段经腰椎间孔椎间融合术（TLIF）单侧固定结合融合器三种不同放置位置的三维有限元模型，探讨融合器三种不同放置位置对脊柱单侧固定应力分布的影响。方法基于正常人L4～L5节段的CT扫描数据，建立该节段TLIF单侧固定的三维有限元模型，并在此基础上分别建立TLIF术式结合融合器前中1／3置人模型（TLIFa）、斜向45。置入模型（TLIFd）及垂直置入模型（TLIFv）。加载后测试在前屈、后伸、侧弯及旋转等各工况下腰椎活动范围、钉棒系统、融合器及对侧小关节应力分布特征。结果该节段TLIF单侧固定非线性有限元模型的活动度分别为前屈9．8°、后伸3．6°、左侧屈4．0°、右侧屈3．7°、左旋转2．5°、右旋转1．8°；3种融合器放置方式模型中融合节段的活动度均较正常模型至少降低77％，且TLIFd的活动度减少最明显；钉棒系统和椎间融合器的应力峰值随运动方向和融合器放置位置不同而存在差异，但应力峰值均在允许的最大范围内；TLIFv对侧小关节应力峰值均高于其它两组，尤其在前屈、后伸及左侧弯工况下最明显，而TLIFd对侧小关节应力峰值在各工况下均最小。结论成功建立了正常人L4～L5节段非线性有限元模型；单枚融合器斜行置入有助于改善固定系统的整体应力分布，并减小对侧小关节的应力载荷。Objective To establish a three-dimensional finite element model of three different cage placement of unilateral fixed L4- L5 segment by transforaminal lumbar interbody fusion （TLIF） , and to determine the effects of three different cage placement on unilateral fixed stress distribution in the spine. Methods Based on the CT scan data of L4-L5 segments of normal subjects, a TLIF unilateral fixed three- dimensional finite element model of the segments was established. In addition, the TLIF cage models with insertion at 1/3 anterior position （TLIFa） , oblique 45~ insertion （TLIFd） and vertical insertion （TLIFv） were established, respectively. After loading, the range of motion of the lumbar spine under various conditions of flexion, extension, lateral bending and rotation, and the stress distribution characteristics of the screw-rod system, cage and the contralateral facet joint were tested. Results The range of motion of the TLIF unilateral fixed nonlinear finite element model was 9.8°flexion, 3.6° extension, 4.0° left bending, 3.7° right bending, 2.5° left rotation, and 1.8° right rotation, respectively. The range of motion of the cage segments of the three cage models with different placement decreased by at least 77% compared with that in the normal model, and the most significant decrease of TLIFd range of motion was found. The stress peaks of the screw- rod system and intervertebral cage were different depending on the direction of motion and placement of the cage, whereas the peak stress was within the maximum allowable range. The contralateral facet joint stress peak in the TLIFv group was higher than that in the other two groups, especially in the flexion, extension and left bending conditions, whi｜e the TLIFd contralateral facet joint stress peak was minimal in each condition. Conclusion The nonlinear finite element model of L4- L5 segments of normal subjects is established successfully. Inclined inclinations of a single fusion cage help to improve the overall stress distribution of

关 键 词：脊柱融合 应力 有限元分析 融合器 内固定 

分 类 号：R563[医药卫生—呼吸系统]