纤维环切口对椎间盘应力分布影响的有限元分析

Finite Element Analysis of the Change of Stress Distribution on Intervertebral Disc After Discectomy

目的:采用三维有限元分析软件建立正常腰椎及纤维环切口模型,分析纤维环切开后在不同生理载荷下椎间盘的应力分布变化。方法:建立正常人体L_(4～5)椎间盘正常模型及纤维环切口模型,导入ANSYS软件进行分析,施加前屈、后伸、侧弯和旋转生理载荷,计算在不同载荷下正常模型与纤维环切口模型椎间盘不同部位的应力,分析椎间盘应力分布变化。结果:构建了腰椎间盘及纤维环环形切开的三维有限元模型,纤维环切开后,在前屈、后伸载荷下,纤维环、髓核应力均集中于纤维环切口处;在各载荷下,椎间盘、髓核、纤维环的最大应力值较正常模型均显著增加。结论:纤维环切开后椎间盘的承载功能明显下降,其髓核和纤维环的应力分布发生变化,这可能是椎间盘再次突出的原因之一。

Objective:By using three-dimensional finite element analysis,to establish a normal lumbar spine and an annulus fibrosus incision model,and to analyze the changes of the stress distribution on the intervertebral disc after the annulus fibrosus incision under different physiological loads.Methods:A normal human L4/5 intervertebral disc model and an annulus fibrosus incision model were established.With the aid of the analysis software,ANSYS,the normal disc and post-incision disc were analyzed with loads generated from four physiological movements,namely anterior flexion,posterior extension,lateral bending and rotation.Thus,changes in distribution on the intervertebral disc were analyzed.Results:A three-dimensional finite element model of lumbar intervertebral disc and annulus fibrosus were constructed.Under the anterior flexion and posterior extension loads,the stresses of both the annulus fibrosus and the nucleus were found to concentrate at the incision site after the discectomy.Also,under all types of loads,the maximum stress values of the intervertebral disc,nucleus pulposus and annulus fibrosus were significantly higher than that of the normal model.Conclusion:The bearing capacity of the intervertebral disc after the incision of the annulus fibrosus is significantly decreased and the stress distribution of the nucleus pulposus and the annulus fibrosus is changed,which may be one of the reasons to develop the recurrence of the intervertebral disc protrusion.