下颈椎前路两种融合术式的三维有限元比较研究

Three-dimensional Finite Element Analysis of Anterior Different Fusion in Lower Cervical Vertebra

目的建立颈4/5/6节段的有限元模型。研究颈椎前路钛板加髂骨块和钛网两种植骨融合术式的载荷传导、界面应力及生物力学分布。方法选择1名健康成年男性,以C4/5/6节段为研究对象。采用螺旋CT扫描获取断层图像,在Mimics软件中三维重建C4/5/6节段骨性结构,然后导入Ansys10.0软件进一步完善椎间盘、韧带等结构,根据临床术式分别建立钛板+髂骨块和钛板+钛网两种内固定融合有限元模型。对模型施加压缩、前屈、后伸、侧屈及旋转5种生理载荷并求解计算,分析模型各结构及椎体终板界面的位移变化和应力分布,比较研究各模型的载荷传导、生物力学分布及稳定性情况。结果轴向压缩主要由钛网/髂骨块承载,伸、屈位主要由钢板螺钉承载,旋转位螺钉受到较大剪切应力,钛网内植物与终板界面处应力集中,两种术式稳定性相当。结论两种融合术式能满足临床手术疗效,但钛网具有应力集中现象。

Objective To develop a three - dimensional finite element model of the C5 and to evaluate the load, stress of interface and biomechanics distribution of C5 fused with two different fusions. Methods The C5 motion segment data were obtained from CT scans of the C5 of a man. After these images were processed, the three - dimensional finite element model of cervical vertebrae anterior titanium plate and bone block and titanium cage were established by software Ansysl0 on the basis of surgery approaches respectively. Loads used in this study were axial compressive, flexion, extension, lateral bending and rotation forces. After the loadings were placed on all the mod- els, the angular motions and the distribution of Von Mises stress of the fused segment were analyzed and compared. Results The condition of compression was conducted nearly by titanium cage/ bone block. The condition of extend and flexion was conducted almost by screws. Crews obtained the greatest shear force in the condition of rotation. The interface of titanium cage - lamina terminals concentrates stress. The stability of two different fusions was correspondent. Conclusion Two different fusions satisfy the need of operation, but the ti- tanium cage concentrates stress.