半限制性人工椎间盘假体植入三维有限元模型的建立

Establish of three dimension finite element model of Semi-constrained integrated artificial disc replacement

目的建立半限制性人工椎间盘假体(SIAD)及腰椎L4—5活动节段高精度三维有限元(FE)模型,拟为生物力学实验研究提供标准数学模型。方法在Auto CAD中设计SIAD假体,基于CT数据通过Mimics建立腰椎L4—5节段三维模型,将SIAD模型放置于L4—5椎间盘,数据导入Abaqus采用有限元装配技术转换成有限元模型。采用轴向负荷400 N以模拟L4—5节段正常的中立位负荷,采用轴向负荷400 N及10 N·m模拟后伸负荷,验证所建立模型的科学性。结果建立了SIAD放置于腰椎L4—5活动节段高精度三维有限元模型,包括:腰椎L4—5活动节段FE模型34 123个节点及162 858个单元,SIAD的FE模型2 144个节点及6 279个单元。力学测试显示中立位负荷及后伸负荷时所建立FE模型力学分布与现有结果一致。结论通过计算机辅助设计可以以自动化程度较高的方法建立高精度NAD假体有限元模型,Mimics通过基于阈值算法及参数化建模提供精确腰椎活动节段模型,两者可以基于有限元装配技术转换成有限元模型,该模型可用于脊柱生物力学的进一步研究。

Objective It is to construct a three dimension finite element model of SIAD （ Semi-constrained integrated artifi- cial disc） replacement and L4-5 motion segment as the standard digital model for further biomechanical research. Methods The SIAD FE model was created using Auto CAD and then it was combined with lumbar segment FE model in aforementioned part one by Abaqus software. The L4_5 model was validated by Force 1 ,a 400 N axial load which was made up of four 100 N ／ stress force, then Force 2 which was composed of 400 N axial load and 10 N · m extension bending moment. Results L4_s seg- ment model was established which consisted of 33 976 nodes, 162 858 elements and the NAD model was consisted of 2 144 nodes, 6 279 elements. The results of load test show that the model of SIAD and L4_5 segment had good effect of visual and mathematics which were according with the existing results. Conclusion Based on Mimics software and CAD methods, the 3D FE model of lumbar motion segment and artificial disc can be constructed automatically with excellent simulation results, and Mimics can provide precise model through calculation based on threshold and parameterization modeling. The implanted L4_s segment can be used for further biomechanical research of lumbar spine.