新型颈椎多孔型（金属）网式融合器的三维有限元分析

Three-dimensional finite element analysis of a novel cervical porous mesh cage

[目的]通过三维有限元分析新型颈椎多孔型(金属)网式融合器应力的分布特点,为临床应用提供理论依据。[方法]建立传统钛网融合器以及新型颈椎多孔型(金属)网式融合器的颈椎前路椎体次全切减压融合内固定术的三维有限元模型。在前屈后伸、左右侧屈、左右旋转等六种工况下施加73.6N的预载荷,1.5Nm的附加运动力矩,观察并分析融合器自身、钛板及融合器与上下终板接触面的Von-Mises应力分布情况以及椎体位移情况。[结果]与传统钛网相比,在六种工况下新型颈椎多孔型(金属)网式融合器自身最大应力减少了84%~98%,C6上终板的最大应力减少了29%~83%,C4下终板的最大应力减少了8%~55%。在大部分工况下,新型颈椎多孔型(金属)网式融合器组的钛板最大应力值较传统钛网融合器组低。在大部分工况下,两种钛网融合器组的终板应力最大值均位于上终板后缘,但新型颈椎多孔型(金属)网式融合器的终板后缘最大应力值要小于传统钛网。[结论]与传统钛网融合器比较,新型颈椎多孔型(金属)网式融合器在颈椎前路椎体次全切减压融合内固定术后具有较强的即刻稳定性,能减少应力集中,减少钛板的应力遮挡,显著降低上下终板的最大应力,更好的预防融合器下沉。

[Objective] To investigate the characteristics of stress distribution on a novel porous (metal) mesh cage, and pro vide theoretical basis for clinical application.[Methods] The three-dimensional finite element models were made to mimic ante rior cervical corpectomy and instrumented fusion with the traditional titanium mesh cage and the novel porous mesh cage. After verifying their validity, a preload of 73.6 N was applied under the six conditions, including flexion, extension, left bending, right bending, left rotation and right rotation, to assess the Von-Mises stress distribution no titanium mesh, titanium plate and verte bral end plate and vertebral displacement.[Results] Under the 6 conditions, the maximal stress on the cage reduced by 84%~ 98%, the maximal stress on the vertebral endplate of C6 went down 29%~83%, and the maximal stress on the endplate under C4 decreased by 8%~ 55% in the novel cage compared with the traditional cage. Under most working conditions, the maximum stress on the titanium plate of the novel cage was lower than that of the traditional cage. Under most conditions, the maximum stress on vertebral endplate in the two kinds of cages was located at the posterior edge of the upper endplate, however, the maxi mum stress on the posterior edge of the endplate in the novel cage was significantly less than the traditional cage.[Conclusion] Compared with the traditional titanium mesh cage, the novel cervical porous mesh cage has stronger immediate stability for anterior cervical corpectomy and instrumented fusion, which reduce stress concentration, stress shielding of the plate and the maximum stress of the upper and lower end plates to facilitate prevention of the cage subsidence.