Relationship between the location of ligamentum flavum hypertrophy and its stress in finite element analysis
Relationship between the location of ligamentum flavum hypertrophy and its stress in finite element analysis
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DOI：
10.1111/os.12675
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发表时间：
2020-06-03
影响因子：
2.1
通讯作者：
Zhang, Zhong-min
中科院分区：
文献类型：
--
作者：
Peng, Yong-xing;Zheng, Zhen-yu;Zhang, Zhong-min
目的应用有限元方法定量描述黄韧带（ligamentum flavum，LF）的应力，并比较健康LF不同部位的应力。方法基于1例22岁健康男性L4-5腰椎的高分辨率CT影像数据，建立完整状态下的三维非线性有限元模型。本研究以LF为研究对象，将其以立体结构的形式纳入脊柱模型中。该模型的有效性进行了验证，通过比较其生物力学指标，如活动范围和轴向压缩压力位移，在特定的负载条件下与公布的结果。为了验证实体LF的准确性，将椎板附件、中央横截面和其他解剖结构指标与已发表文献中的数字进行了比较。利用ANSYS和AutoCAD软件测量不同工况下LF表面的平均和最大vonMises应力，确定LF腹侧和背侧以及外侧和椎板部分的表面应力差异。在健康的有限元模型中，椎板附着体、中央横截面、LF的高度和宽度与已发表的结果一致。在健康模型中，在500 N的压缩预载荷下，结合屈曲、伸展、以及侧向和旋转力矩（10 Nm）。最明显的表面应力的差异与屈曲运动，与其他状态相比，最大应力差异近241%，平均应力差异228%。就整个LF背侧而言，最大表面应力几乎都集中在背侧相邻的小关节部分。另外，外侧部的最大应力和平均应力分别比椎板部高77%、72%、15%、11%、71%和153%、39%、54%、200%、212%。LF肥大与应激呈正相关。
Objective To quantitatively describe the stress of the ligamentum flavum (LF) using the finite element method and to compare the stress at different parts of the healthy LF.Methods Based on the high resolution computed tomography imaging data of a healthy 22-year-old man, three-dimensional nonlinear L4-5 lumbar finite element model (FEM) representing intact condition was developed. The LF, as the object of the present research, was incorporated into the spinal model in the form of solid three-dimensional structure. The model's validity is verified by comparing its biomechanical indices, such as range of motion and axial compression pressure displacement, with published results under specific loading conditions. To authenticate the accuracy of the solid LF, the lamina attachments, the central cross-section, and other anatomy indicators were compared with figures in the published literature. After the average and maximum von Mises stress on the surface of LF under various working conditions were measured using ANSYS and AutoCAD software, the surface stress difference in the LF between the ventral and dorsal sides as well as the lateral and lamina parts were determined.Results The FEM predicted a similar tendency for biomechanical indices as shown in previous studies. The lamina attachments, the central cross-section, and the height as well as the width of the LF in the healthy FEM were in accordance with published results. In the healthy model, the average and maximum von Mises stress in the shallow layer of the LF were, respectively, 1.40, 2.28, 1.76, 1.48, 1.38 and 1.79, 2.41, 1.46, 1.42, 1.71 times that in the deep layer under a compressive preload of 500 N incorporated with flexion, extension, and lateral and rotational moments (10 Nm). The most conspicuous difference in surface stress was observed with the flexion motion, with a nearly 241% difference in the maximum stress and a 228% difference in the average stress compared to those in other states. As far as the whole dorsal side of the LF was concerned, the maximum surface stress was almost all concentrated in the dorsal neighboring facet joint portion. In addition, the maximum and average stress were, respectively, 77%, 72%, 15%, 11%, 71% and 153%, 39%, 54%, 200%, 212% higher in the lateral part than in the lamina part.Conclusion Based on the predisposition of LF hypertrophy in the human spine and the stress distribution of this study, the positive correlation between LF hypertrophy and its stress was confirmed.