【作者】 张志；

【导师】 夏虹；

【作者基本信息】 广州中医药大学 ， 中医骨伤科学， 2010， 硕士

【摘要】 目的(1)测量腰椎L5峡部的有关解剖学数据并进行统计分析；(2)制作腰椎峡部外1／2缺损和内1／2缺损病理模型；(3)对腰椎峡部外1／2缺损和内1／2缺损病理模型的抗疲劳特性进行对比分析；(4)制作腰椎峡部外1／2缺损有限元模型；(5)求解分析腰椎峡部裂应力的传导分布特征。方法(1)成人新鲜腰椎标本12例,所有标本均取自意外死亡的成年男性新鲜尸体,具体年龄不祥,均无腰椎疾患。常规解剖L5椎体,彻底切除软组织,仅保留骨性部分。用聚甲基丙烯酸甲酯(牙托粉,PMMA,自凝型,上海齿科材料厂生产)包埋。包埋的目的是以备装卡固定标本使用,放于-20℃的低温冰箱中保存备用。用游标卡尺对腰椎峡部的宽度进行测量。每一标本重复测量两次,以求精确。对正常腰椎峡部左右侧宽度对比进行统计分析。(2)12例模型随机分为两组,每组6例,分别用咬骨钳咬除腰椎峡部外1／2或内1／2骨质,制作腰椎峡部外1／2缺损和内1／2缺损病理模型。采用游标卡尺对剩余腰椎峡部的宽度进行测量。对腰椎峡部外1／2缺损模型与腰椎峡部内1／2缺损模型的峡部缺损后宽度进行统计对比。(3)将标本固定于脊柱三维运动试验机上,依次将腰椎峡部外1／2缺损和内1／2缺损病理模型标本置于生物材料力学试验机MTS-858 Mini Bionix (MTS, Minneapolis, MN, USA)上,分别给予压缩负荷,频率为0.5 Hz,加载60～600 N的周期性正弦波。整个试验过程中经常喷洒生理盐水于标本上,以保持标本在试验过程中湿润。记录断裂次数进行统计学分析。(4)使用螺旋CT,以1mm的间隔,对1具男性青年新鲜尸体的腰椎标本沿轴向进行断层扫描。腰椎的CT图像输入计算机,利用MIMICS11.1提取图片中轮廓线数据矩阵,转换为dat文档后输入ANSYS10.0建模。(5)在前处理软件Mimics 11.1与Simpleware3.1中制作L4椎体外1／2腰椎峡部缺损模型,然后导入ANSYS 10.0软件有限元系统,在上椎体上终板面上施纯力偶矩,施加5牛顿*米前屈、后伸、侧弯载荷,然后进入Ansys求解器,求解分析腰椎峡部裂应力的传导分布特征。结果(1)正常L5左侧腰椎峡部宽度为15.06±0.83,正常右侧腰椎峡部宽度为14.85±0.72,左右侧对比P=0.52>0.05,差异无统计学意义。(2)腰椎峡部外1／2缺损模型峡部宽度为5.24±0.41,腰椎峡部内1／2缺损模型峡部宽度为5.15±0.34,对比P=0.57>0.05,差异无统计学意义。(3)腰椎峡部外1／2缺损模型峡部断裂次数为25160±1019,腰椎峡部内1／2缺损模型峡部断裂次数为18782±3126,对比P=0.006<0.05,差异有统计学意义。(4)建立了一个较为详尽的腰部三维模型。该模型由骨质结构和软组织结构两部分组成。骨质结构包括了腰椎运动节段L4-L5；软组织部分包括椎间盘、软骨及腰部主要的韧带和肌肉。整个模型包括5668个8-node Solid 45单元、8236个壳单元、239个连接单元,由5462个面、20811条线、81221个结点组成。(5)有限元实验结果显示：后伸右旋时左侧关节突受力最大,Von Mises应力为188MPa,其力学方向与X轴成约45度角；前屈旋转Von Mises应力为164MPa,其与x轴成角约45度；侧弯旋转最小,Von Mises应力为142MPa,其与x轴成角约15度。结论(1)腰椎峡部外1／2缺损模型抗疲劳性优于腰椎峡部内1／2缺损模型,腰椎峡部内1／2承担了更多的腰椎负荷应力,腰椎峡部外1／2更容易疲劳骨折。(2)L4椎体双侧外1／2腰椎峡部缺损腰椎节点应力分布图显示在旋转外力作用下关节突以及椎弓根周边部位出现高应力区。结果表明,腰椎后伸+右旋转左侧受力最大,对关节突应力分布产生明显影响。而棘突并非旋转轴心,结果显示应力分布无集中趋势。结果提示当峡部缺损达到1／2时,残余峡部的力学强度下降显著,相当一段时期内应尽量避免后伸等有害应力。(3)前纵韧带、后纵韧带、棘间韧带等韧带结构附着处应力应变无明显改变。更多还原

【Abstract】 Objective(1) To measure the L5 isthmus portion of lumbar vertebra, get anatomic data and analyze it.(2) To make pathologic defect models of isthmus external 1/2 and internal 1/2(3) To compare and analyze the anti-fatigue features of these two models(4) To make finite element model on the defective isthmus external 1/2(5) To analyze and solve the transmit and distribution features of breaking stress on the isthmus portion of lumbar vertebraMethods(1) Take 12 fresh lumbar vertebra specimens. All the specimens are taken from fresh adult male corpse died from accident, age unidentified, without lumbar vertebra disease. Dissect L5 centrum, remove soft tissue and maintain only the bone part. Embedding with PMMA to fix the specimen (dental base acrylic resin powder, PMMA, self-cures. Manufactured by shanghai orthodontics material factory). Store them in-20℃freezer. Use electric vernier caliper to measure the width of lumbar vertebra isthmus. Each specimen should be measured twice so as to ensure the accuracy. Compare the left and right isthmus side width and analyze them.(2) Divide these 12 specimens randomly into 2 groups. Use rongeur to remove respectively the external 1/2 isthmus and the internal 1/2 isthmus bone and then make pathological defect models. Use electric vernier caliper to measure the width of the remaining isthmus. Compare the width of the external 1/2 isthmus defect model and the internal 1/2 isthmus defect model.(3) Fix the specimen on spine 3D movement test machine, put the external 1/2 isthmus defect model and the internal 1/2 isthmus defect model on mechanic test machine MTS-858 Mini Bionix (MTS, Minneapolis, MN, USA). Give each of them compressed load, with 0.5 Hz frequency and 60-600 N periodic sine waves. Keep spraying physiological saline onto the specimen throughout the test to keep them moisture. Record the breakage times and analyze them.(4) Take a young male fresh corpse, use spiral CT to scan each layer of the lumbar vertebra specimen along axial direction, each layer space is 1mm. Input the CT image into computer, use MIMICS 11.1 to collect matrix of the contour line data, transform them into dat files and then put them into ANSYS 10.0 to build up model.(5) Use pre-treatment software Mimics 11.1 and Simpleware3.1 to make L4 vertebra isthmus external 1/2 defect model, and then lead it in to finite element system with ANSYS 10.0, and then apply force onto the upper centrum surface. Apply 5N* meter load, ante flexion, rear protraction and side bend, and then enter the Ansys solver to analyze and solve the transmit and distribution features of breaking stress on the isthmus portion of lumbar vertebraResult(1) The width of the normal L5 left isthmus portion of lumbar vertebra is 15.06±0.83, the right width is 14.85±0.72. The difference between the left width and the right width is P=0.52>0.05, no statistic value.(2) The isthmus width of the external 1/2 isthmus defect model is 5.24±0.41, the isthmus width of the internal 1/2 isthmus defect model is 5.15±0.34. The difference between the external and the internal isthmus width is P=0.57>0.05, no statistic value.(3) The breakage times of the external 1/2 isthmus defect model are 25160±1019, while the internal 1/2 isthmus defect model are 18782±3126. The difference between them is P=0.006<0.05, has statistic value.(4) Build up a detail 3D model for the waist, including bone structure and soft tissue. The bone structure include lumbar vertebra movement segment L4-L5; the soft tissue include inter vertebral disk, gristle, and main ligament and muscle on the waist. The whole model include 5668 8-nodeSolid 45 units,8236 shell units and 239 connecting units, consisting of 5462 surfaces,20811 lines and 81221 nodal points.(5) The result of finite element experiment shows:in the rear protraction rotation, the left side joint has the maximum stress; its dynamic direction forms a 45 degree angle with the X axis. In the ante flexion rotation, the stress is 164n; it forms an approximate 45 degree angle with the X axis. Side bend rotation has the minimum stress; it forms an approximate 15 degree angle with the X axis.Conclusion(1) The anti-fatigue features of the external 1/2 lumbar vertebra isthmus defect model is better than the internal 1/2. The internal 1/2 bears more loads. The external 1/2 is easier to become fatigue and fracture.(2) According to the stress distribution map of the L4 external 1/2 isthmus portion of lumbar vertebra, the articular process and vertebral pedicle neighboring part exist high stress zone. The result shows that rear protraction plus right rotation have the maximum stress, which has distinctive effect on articular process distribution. While the spinous process is not the rotation center, the result shows that there is no concentration trend of stress distribution. The result also shows that when the isthmus defection reaches 1/2, the stress of the remaining isthmus decreases notably, the rear protraction should be avoided in a period of time.(3) There is no obvious stress change to the anterior longitudinal ligament, the posterior longitudinal ligament, interspinal ligaments or other ligament structures.更多还原