构建强直性脊柱炎后凸畸形的三维有限元模型

Establishment of a three-dimensional finite element model of ankylosing spondylitis kyphosis

背景:完整的三维有限元模型不仅可以建立逼真的立体模型,进行术前规划,并且还可以在模型上进行模拟截骨,分析生物力学,以期达到指导临床手术的作用。目的:建立强直性脊柱炎后凸三维有限元模型,为后续的一系列研究提供有效的数字化平台。方法:选取1例30岁强直性脊柱炎后凸病例C_1至骶尾骨的CT断层图像,将CT数据输入Mimics 17.0医学三维重建软件中,建立脊柱后凸三维几何模型。再将几何模型导入Geomagic Studio 2013软件中,对三维几何模型进行后续优化图像处理,生成修复后的脊柱后凸几何曲面模型。使用Unigraphics NX 8.5导入建立的脊柱后凸曲面模型,建立钙化的韧带模型,切除部分无用的骶骨模型,最后导入ANSYS 15.0有限元分析软件中,设置材料参数,生成完整的强直性脊柱炎后凸三维有限元模型。结果与结论:成功建立了完整强直性脊柱炎后凸三维有限元模型,包括10节点四面体单元398 370个,668 538个节点。为下一步的生物力学分析提供了可靠的数字化平台。

BACKGROUND： The full three-dimensional finite element model can not only establish a realistic three-dimensional model, but also can simulate the osteotomy on the model. Analysis of biomechanics guides the clinical operation. OBJECTIVE： To establish a three-dimensional finite element model of ankylosing spondylitis kyphosis and provide an effective digital platform for further studies.METHODS： A 30-year-old male patient with ankylosing spondylitis kyphosis participated voluntarily in the current study. CT images obtained from CT transverse scanning from C1 to the sacrococcyx were imported into Mimics 17.0 software to establish a three-dimensional geometric model of the posterior spine. The geometric model was then imported into Studio Geomagic 2013 software. For the subsequent optimization of image processing, the posterior spine convex geometry was established on the three-dimensional geometric model. We used Unigraphics NX 8.5 to establish the spinal kyphosis surface model, then added modeling of calcification of the ligaments, partial resection of useless sacral bone, and finally, imported the model into ANSYS 15.0 finite element analysis software, then added the ligaments and set the parameters of the material, generating a complete three-dimensional finite element model of ankylosing spondylitis.RESULTS AND CONCLUSION： A three-dimensional finite element model of complete ankylosing spondylitis was successfully established. Using the ten-node approach, we generated 398 370 tetrahedral elements, and 668 538 nodes. This will provide a reliable digital platform for the next step of biomechanical analysis.