不同分型腰椎-骨盆矢状位序列的模型建立及应力分析

Model establishment and stress analysis on the different types of sagittal lumbar-pelvic alignment

中文关键词:  腰椎-骨盆矢状位序列  有限元分析  生物力学

英文关键词:The sagittal lumbar-pelvic alignment  Finite element analysis  Biomechanics

中文摘要:

  【摘要】 目的：依据腰椎-骨盆矢状位序列分型，建立4例腰椎有限元模型，比较其在椎间盘及椎弓峡部的应力分布。方法：依据腰椎-骨盆矢状位序列分型，选取4名青年健康志愿者，每型各1名志愿者（Ⅰ型，女，20岁；Ⅱ型，男，21岁；Ⅲ型，男26岁；Ⅳ型，女，19岁）。4名志愿者行腰椎CT检查，并通过Mimics、Geomagic、Hypermesh、ABAQUS软件构建4例L1~L5腰椎有限元模型。在施加400N垂直压缩载荷和沿X、Y、Z轴方向施加10N·m的力矩载荷后，计算模型在前屈、后伸、侧弯、扭转工况下的平均刚度，并验证模型的有效性。只施加400N垂直压缩载荷的情况下，分析各模型纤维环及椎弓峡部的应力分布。结果：4例模型在前屈、后伸、侧弯、扭转工况下平均刚度与既往体外实验文献结果较为接近。在承受400N的垂直压缩载荷下，4例模型均从L1/2至L4/5纤维环所受应力逐渐增加，且应力大多集中在纤维环的后部；Ⅰ型和Ⅱ型椎弓峡部的应力主要集中在L4，而Ⅲ型和Ⅳ型椎弓峡部应力主要集中在L3。从Ⅰ型到Ⅳ型，L4/5纤维环后部平均应力与L1/2纤维环后部平均应力的比值逐渐减少（203.69%，197.58%，167.74%，139.85%）；L5双侧椎弓峡部平均应力与L1双侧椎弓峡部平均应力的比值逐渐增加（204.38%，212.59%，271.43%，292.98%）。结论：本实验所建立的4例腰椎有限元模型验证有效，可以进行生物力学分析与模拟，不同类型腰椎-骨盆矢状位序列个体腰椎在纤维环及椎弓峡部的应力分布存在差异。

英文摘要:

  【Abstract】 Objectives: To establish 4 cases of lumbar finite element model, according to the classification of sagittal lumbar-pelvic alignment, and to compare the stress distribution in the intervertebral disc and the vertebral arch isthmus. Methods: On the basis of the sagittal lumbar-pelvic alignment, 4 young healthy volunteers were selected, 1 volunteer for each type (type Ⅰ, female, 20 years old; type Ⅱ, male, 21 years old; type Ⅲ, male, 26 years old; type Ⅳ, female, 19 years old). 4 volunteers underwent lumbar CT examination, and were built L1-L5 lumbar finite element models of 4 cases by using Mimics, Geomagic, Hypermesh, ABAQUS. After applying the 400N vertical compression load and the torque load of 10N·m along the X, Y and Z axes, the average stiffness of the models was calculated under the conditions of flexion, extension, lateral bending and axial rotation, and the validity of models was verified. Under the condition of only applying 400N vertical compression load, the stress distributions of the annulus fibrosus and the vertebral arch isthmus were analyzed. Results: Under the conditions of flexion, extension, lateral bending and axial rotation, the average stiffness of 4 cases was similar to that of previous vitro experiment. After applying 400N vertical compression load, the stress of annulus fibrosus from L1/2 to L4/5 increased gradually, and the stress was mostly concentrated in the posterior part of annulus fibrosus. In type Ⅰ and Ⅱ, the stress of isthmus was mainly focused on L4, however, in type Ⅲ and Ⅳ, the stress of isthmus was mainly focused on L3. From type Ⅰ to type Ⅳ, the mean stress of the posterior part of annulus fibrosus from L4/5 to L1/2 decreased gradually(203.69%, 197.58%，167.74%, 139.85%). However, the mean stress of bilateral vertebral arch isthmus from L5 to L1 increased gradually(204.38%, 212.59%, 271.43%, 292.98%). Conclusions: In the different types of sagittal lumbar-pelvic alignment, there are different types of stress distribution of the annulus fibrosus and the vertebral arch isthmus.