中国组织工程研究 ›› 2018, Vol. 22 ›› Issue (31): 4982-4986.doi: 10.3969/j.issn.2095-4344.0856

• 骨与关节生物力学 bone and joint biomechanics • 上一篇    下一篇

腰骶椎带锁轴向融合内固定器的有限元分析

易 新,宋西正   

  1. 南华大学附属第一医院,湖南省衡阳市 421001
  • 出版日期:2018-11-08 发布日期:2018-11-08
  • 通讯作者: 宋西正,南华大学附属第一医院,湖南省衡阳市 421001
  • 作者简介:易新,男,1987年生,湖南省衡阳市人,汉族,2014年南华大学毕业,硕士,医师,主要从事脊柱微创研究。

Finite element analysis of locking axial lumbosacral interbody fusion cage

Yi Xin, Song Xi-zheng   

  1. First Hospital of Nanhua University, Hengyang 421001, Hunan Province, China
  • Online:2018-11-08 Published:2018-11-08
  • Contact: Song Xi-zheng, First Hospital of Nanhua University, Hengyang 421001, Hunan Province, China
  • About author:Yi Xin, Master, Physician, First Hospital of Nanhua University, Hengyang 421001, Hunan Province, China

摘要:

文章快速阅读:

 
 
文题释义:
脊柱有限元建模:通过CT、MRI等方式获取物体图像,再构建模型,在图像建模法中运用CT技术扫描图像,可最大程度还原原物体信息,再通过相关软件指定相应空间边缘坐标,得出更真实可靠的有限元模型。此法不受对象的复杂结构所限制,且精度较高,介于目前CT、MRI等影像学技术的发展及人体解剖结构的复杂性,运用图像建模的方法更适合于临床生物力学特性的研究,目前已成为骨科有限元仿真建模的主要方法。
有限元网格划分:CT扫描几何形状输入有限元软件中,建立成复杂三维有限元模型,在模型基础上直接进行网格划分,从而得到了逼真的几何模型。腰骶椎节段应包括椎体、椎板、上下关节突、椎间盘及韧带等结构,定义椎体为网状的连续体和皮质外壳;皮质骨和骨小梁分别模拟为同向、异向弹性单元;髓核定义为高弹性、不可压缩的连续体;纤维环模拟为同轴的交叉编制纤维层,内层为实性连续体;韧带则为非线性弹簧单元。
 
摘要
背景:为提高椎间融合的腰骶椎稳定性及融合率,作者结合国人腰骶椎研制了一种腰骶椎经皮带锁轴向融合器。
目的:建立有效的腰骶椎带锁轴向融合固定三维有限元模型,分析不同载荷下螺钉应力分布,为其提供需要改进的目标和评价指标。
方法:利用逆向工程软件Mimics、Geomagic建立正常成人腰骶椎有限元模型,模拟手术过程将腰骶椎带锁轴向融合器装配到有效的腰骶椎模型中,对其进行网格模型划分,建立起装配有带锁轴向融合器的腰骶椎有限元网格模型,根据腰骶椎和内固定的材料属性,对模型进行赋值,导入Solid works 2011中得到最终有限元模型。对模型施加生理及极限载荷,进行前屈、后伸、侧弯、旋转载荷运动,在Hypermesh软件完成带锁轴向融合器内部应力分布,评价其生物力学性能。
结果与结论:在垂直压缩+前屈+左旋工况极限载荷下,骶椎带锁轴向融合器所承受的压强最大,为1 500.08 MPa,应力集中点为带锁轴向内固定融合器植骨孔左右两侧;其次为垂直压缩+前屈+右旋极限载荷下,带锁轴向融合器所承受的最大压强为1 318.00 MPa,应力集中点为带锁轴向内固定融合器植骨孔左右两侧,植骨孔上下两侧压强较小。在生理载荷下,内固定器能够提供足够的强度,保证稳定性和提高植骨融合率;在垂直压缩+前屈+旋转工况极限载荷下,内固定器承受的最大应力超过螺钉屈服强度,应改进工艺及加强植骨孔薄弱环节,术后早期卧床、佩戴支具,避免过伸、过屈或扭转等高强度运动。

中国组织工程研究杂志出版内容重点:人工关节;骨植入物;脊柱骨折;内固定;数字化骨科;组织工程
ORCID: 0000-0003-2301-861X(易新)

关键词: 带锁轴向融合器, 腰骶椎, 有限元, 应力, 生物材料

Abstract:

BACKGROUND: In order to improve lumbosacral stability and fusion, we developed a locking axial lumbosacral fusion cage for Chinese lumbosacral vertebrae.

OBJECTIVE: To establish an effective three-dimensional finite element model of axial lumbosacral interbody fusion with locking plate and to analyze the stress distribution of the screw under different loads, and to provide targets and evaluation indexes to be improved.
METHODS: A normal adult lumbosacral vertebra finite element model was established by reverse engineering software Mimics and Geomagic. The locking axial lumbosacral fusion cage was assembled into the effective lumbosacral vertebra model by simulating the surgical procedure. The mesh model was divided into two groups. A finite element mesh model of lumbosacral vertebrae fitted with the locking axial fusion cage was established. According to the material properties of lumbosacral vertebrae and fusion cages, the model was assigned and imported into SolidWorks 2011 to obtain the final finite element model. Under physiological and ultimate loads, the model was subjected to flexion, extension, lateral bending and rotation motions. The stress distribution in the axial-direction cage with locking was completed by Hypermesh software to evaluate its biomechanical properties.
RESULTS AND CONCLUSION: The maximal compressive force of the locking axial lumbosacral fusion cage under the vertical compression+flexion+left-handed condition was 1 500.08 MPa, and the stress concentration point was located at the left and right sides of the bone hole. Then, under the vertical compression+flexion+right-hand limit load, the maximum pressure to be absorbed by the fusion cage was 1 318.00 MPa, and the stress concentration point was at the left and right sides of the bone hole, and there was a lower pressure at the upper and lower sides of the bone hole. Physiological load holders provide adequate strength, stability and bone-graft fusion. Under vertical compression+flexion+rotation conditions, the maximum stress exceeds the yield strength of the screw. Therefore, to improve the process and strengthen the weak points of bone graft, postoperative early bed rest, wearing a brace, and to avoid over-stretch, flexion or torsion and other high strength movement are recommended.

中国组织工程研究杂志出版内容重点:人工关节;骨植入物;脊柱骨折;内固定;数字化骨科;组织工程

Key words: Internal Fixators, Lumbar Vertebrae, Finite Element Analysis, Tissue Engineering

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