王志坤,夏 虹,谢文伟,李再学,张 余,马立敏.镁合金中空螺钉固定治疗ⅡA型齿状突骨折的三维有限元分析[J].中国脊柱脊髓杂志,2013,(5):459-464. |
镁合金中空螺钉固定治疗ⅡA型齿状突骨折的三维有限元分析 |
中文关键词: 齿状突骨折 镁合金 中空螺钉 有限元分析 |
中文摘要: |
【摘要】 目的:建立正常枢椎及中空螺钉固定ⅡA型齿状突骨折的三维有限元模型,分析镁合金螺钉固定ⅡA型齿状突骨折的稳定性。方法:通过CT扫描1例正常成年男性志愿者颈椎获取枢椎的空间结构信息,导入三维重建软件Mimics 10.01、Solidworks 2010,建立正常枢椎及中空螺钉固定ⅡA型齿状突骨折的三维有限元模型。在有限元软件Ansys 13.0中分析正常枢椎模型、ⅡA型齿状突骨折中空螺钉(镁合金螺钉、钛合金螺钉)固定模型,分别模拟颈椎后伸、前屈时受到水平载荷50N、100N、150N、200N的作用力及颈椎旋转时分别受到50N·mm、100N·mm、150N·mm、300N·mm扭矩时,测量齿状突的最大位移与最大应力、枢椎椎体的最大应力及螺钉的最大应力。钛合金螺钉弹性模量为108000MPa,屈服强度为930MPa;镁合金螺钉弹性模量为45000MPa,屈服强度为193MPa。结果:所建正常枢椎及ⅡA型齿状突骨折中空螺钉固定有限元模型外形逼真,几何相似性好。颈部前屈、后伸、旋转三种活动状态下,受到不同载荷时镁合金螺钉的最大应力均小于钛合金螺钉,两种螺钉的最大应力均小于其屈服强度;两种材料中空螺钉固定的ⅡA型齿状突骨折模型中齿状突、枢椎椎体的最大应力均小于皮质骨应力阀值(200MPa),齿状突的最大位移是正常枢椎齿状突最大位移的5~8倍,均小于1mm(有限元模型中网格大小为1mm)。结论:应用CT扫描获取枢椎空间结构信息建立的枢椎三维有限元模型可用于生物力学实验,镁合金中空螺钉在固定ⅡA型齿状突骨折时足以维持其稳定性。 |
Magnesium alloy hollow screw for type ⅡA odontoid fracture: a finite element analysis |
英文关键词:Odontoid fracture Magnesium alloy Hollow screws Finite element |
英文摘要: |
【Abstract】 Objectives: To establish a finite element model of type ⅡA odontoid fracture fixed by screw and analyze the stability of magnesium alloy screw fixation. Methods: Spatial structure information acquisition axis by CT scanning a normal male volunteer′s cervical vertebra, the 3D data were imported to software Mimics 10.01, Solidworks 2010 to establish the three-dimensional finite element model of normal axis and odontoid process fracture of ⅡA type fixed by hollow screw. The finite element software Ansys 13.0 was used to analyze hollow screw axis, the normal model of odontoid fractures of type ⅡA(magnesium alloy, titanium alloy screws fixed screw), respectively, and the simulation of cervical extension, flexion when subjected to horizontal load of 50N, 100N, 150N, 200N force and cervical rotation by 50N·mm, 100N·mm, 150N·mm, 300N·mm torque were added to meassure the maximum displacement of odontoid process, the maximum stress of odontoid process, the maximum stress of C2 vertebral body and the maximum stress of screw. The screw elastic modulus of titanium alloy was 108000MPa, with a yield strength of 930MPa; the elastic modulus of magnesium alloy was 45000MPa, with a yield strength of 193MPa. Results: The normal axis and hollow screw fixation after establishment of the finite element model was realistic and geometric similarity. At three kinds of state of flexion, extension and rotation, the maximum stress of magnesium alloy screw under different load was less than the titanium alloy screw, the stresses of both alloys were less than the yield strength; the maximum stress of odontoid process and the maximum stress of C2 vertebral body of the model of odontoid process fracture of ⅡA type fixed by two kinds of materials respectively was less than the cortical bone stress threshold(200Mpa), the maximum displacement of odontoid process was 5-8 timesthe to maximum displacement normal axis, both were less than 1mm(the size of grid finite element model was 1mm). Conclusions: The filite element model established by CT-scan and axial space structure can be used for biomechanical test, magnesium alloy hollow screw fixation of type ⅡA odontoid process fracture is enough to ensure stability. |
投稿时间:2012-12-19 修订日期:2013-03-25 |
DOI:10.3969/j.issn.1004-406X.2013.5.459.5 |
基金项目:全军医学科研“十二五”重点项目(编号:bws11c065);全军医学科研“十二五”面上项目(编号:cws11c268) |
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