The finite element testing to the anterior atlantoaxial reduction plate system / 中国医师杂志

ABSTRACT

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.