寰枢椎前路复位钢板系统的有限元测试

目的了解寰枢椎前路复位钢板系统（TARP）在治疗寰枢椎脱位时的应力分布，为TARP系统的进一步改进提供参考。方法应用中国数字人男1号数据集（CT）建立寰枢椎脱位前路复位钢板螺钉固定的有限元（FEM）模型，在此模型上模拟施加各种载荷条件下进行有限元分析，测定钢板、螺钉及寰枢椎在不同载荷条件下内部结构变化和应力分布。结果TARP钢板固定后，在前屈、后伸、侧弯及旋转等不同状态下，内固定器械主要应力均集中在TARP钢板的中部（应力为0．159×10^8-0．732×10^8Pa）和枢椎螺钉的根部（应力为0．214×10^9-0．958×10^9Pa）。但前屈运动时集中在寰枢关节面上（应力为0．512×10^7Pa）；后伸运动时集中在寰椎侧块与后弓的连接部（应力为0．582×10^7Pa）；侧弯运动及旋转运动时集中在枢椎螺钉的钉道部位（应力分别为0．287×10^9Pa及0．241×10^9Pa）。结论尽管不同部位的应力大小不同，但无论在哪种运动状态下，螺钉的最大应力均在根部，TARP钢板的应力均集中在中部，因此螺钉根部及钢板中部力学强度的大小是决定TARP钢板系统力学疲劳性能的关键。

The finite element testing to the anterior atlantoaxial reduction plate system

Objective To discuss the TARP (transoral pharyngeal atlanto axioal reduction plate,TARP) stress distribution under the condition of atlantoaxial dislocation treatment with the TARP system and explore the possible suggestion for the further innovation of the TARP system.Methods A fixed Finite Element model was constructed for transoral atlantoaxial reduction plate system based on the CT digital data of the China Digital Human NO.1.The internal structure changes and the stress distribution of TARP system under different loads were imitated and analyzed.Results The results showed that,after the fixation of the TARP system,different parts of the atlantoaxial had different stress under anteflexion,extension,lateral bending and rotation,the internal fixation parts located mainly at the mid-part of the TARP(0.159 × 108 ～0.732 × 108 Pa) and the root of the screw(0.214 × 109 ～0.958 × 109 Pa).Beside that,when using anteflexion,the stress mainly focused on the articular surface of the atlantoaxial(0.512 × 107 Pa).As for extension,the stress mainly focused on the part between the lateral mass and anterior arch (0.582 × 107 Pa).While lateral bending or rotation,the stress mainly focused on the axial screw nailing path (0.287 × 109 Pa and 0.241 × 109 Pa).Conclusions Although different parts of the TARP plate have different stress,its maximum stress lied in the root of the screw.The stress of plate mainly focused on the mid - part,no matter in what state of motion,therefore,the root of the screw and the mid-part of the plate bore the biggest stress,their strength decided the fatigue property of the TARP system.