颈椎曲度异常对椎间盘应力分布影响的有限元分析

Finite element analysis of the effect of the cervical curvature on the stress distribution in cervical intervertebral disc

目的利用有限元模型研究颈椎曲度变化对椎间盘应力分布的影响。方法根据志愿者颈部CT数据建立曲度正常、变直、后凸3种颈椎有限元模型,计算不同载荷下颈椎间盘的应力分布。结果 (1)同一载荷下,3个颈椎模型中C3～4椎间盘应力最小,C5～6椎间盘应力最大,差异有统计学意义(P <0. 05)。(2)重力载荷作用下,C3～4、C4～5、C5～6、C6～7椎间盘应力曲度后凸模型显著大于曲度正常模型及曲度变直模型(P <0. 05)。(3)前屈+重力载荷下,各模型中椎间盘应力均明显大于单纯重力载荷(P <0. 05),其中C4～5、C5～6椎间盘应力曲度后凸模型和曲度变直模型明显大于曲度正常模型(P <0. 01)。(4)后伸+重力载荷下,各模型椎间盘应力明显小于前屈+重力载荷(P <0. 05)。结论根据颈椎弧度建立的有限元模型,能够较好地反映颈椎曲度变化对椎间盘应力的影响,可以用来研究颈椎病预防及治疗措施的有效性。

Objective To study the effect of cervical curvature change on the stress distribution of intervertebral disc using the finite element analysis.Methods Three cervical vertebrae finite element models with the normal cervical curvature,straightened curvature and cervical kyphosis were reconstructed in software,the stress distribution of cervical intervertebral disc was calculated by the gravity loading,anteflexion and gravity loading,and post tensioned loading.Results ①Under the same load condition,the minimum stress of three cervical vertebrae models was in the C 3~4 intervertebral disc,and the maximum stress was in the C 5~6 intervertebral disc,there was significant difference(P<0.05).②Under the cranial gravity load,the stress of C 3~4,C 4~5,C 5~6 and C 6~7 intervertebral discs in the kyphosis curvature cervical model was significantly greater than that in the normal curvature cervical model and the straighted curvature cervical model(P<0.05).③Under the anteflexion and gravity load,the stress of intervertebral disc of all groups were significantly greater than that in the only gravity load(P<0.05);among them,the stress of C 4~5,C 5~6 in the kyphosis curvature cervical model and the straighted curvature cervical model were significantly greater than those in the the normal curvature cervical model(P<0.01).④Under post-tensioned load,the disc stress in all groups was significantly lower than that of the anteflexion and gravity load(P<0.05).Conclusions The finite element models of cervical vertebra according to the real cervical curvature can be used to evaluate intervertebral disc stress,and to study the effectiveness of prevention and treatment for the cervical spondylosis.