目的 对Medpor修复眶底缺损进行三维有限元的建模,并分析其生物力学性质,研究Medpor材料植入眶底后的位移及应力情况,为临床提供参考。方法 将患者术前头颅螺旋CT数据导入Mimics软件后,进行左侧眶下壁三维重建,应用有限元软件对模型进行网格划分,通过CT扫描灰度值的转换,对各部分材质进行赋值,再对整体模型施加重力载荷,计算并分析Medpor材料植入眶底后在不固定、1枚螺钉固定及2枚螺钉固定的不同状态下的位移与应力情况。结果 构建了Medpor修复眶底缺损的三维有限元模型。无固定螺钉情况下,Medpor材料位移较大,几乎无应力;在有固定螺钉情况下,1枚固定螺钉的应力值与2枚固定螺钉应力值没有明显差异。结论 首次建立了关于Medpor修复眶底缺损的三维有限元模型。利用有限元方法发现,螺钉的植入能够对Medpor材料起到良好的固定作用,其中1枚螺钉与2枚螺钉的固定作用相似。

Objective To establish three-dimensional finite element model of the repair for orbital defect with Medpor implant, and to explore biomechanical characteristics including displacement and stress analysis of Medpor implant with the state of implantation in orbital floor, in order to provide the reference basis for surgeons. Methods The three dimensional model was established by Mimics software via reading the CT data of DICOM format of a patient with left orbital floor fracture. Followed the 3D model remeshing by Magics finite element software, material properties assignment with gray value conversion, the three-dimensional finite element model for the repair of orbital defect with Medpor implant was modeled. Then displacement and stress analysis of Medpor implant was done by finite element method under the load of different simulated gravity: no fixation, one and two screws fixation. Results The finite element was established in this study successfully.No fixation between Medpor implant and orbital wall allowed large displacement with no stress. Fixation by one screw or two screws has the same stress value. Conclusion Three-dimensional finite element model of the repair for orbital defect with Medpor implant was established firstly. According to finite element method, the screw implant can play a good role in the fixation of Medpor,and fixation by one screw or two screws has the same effect.