Chinese Journal Of Clinical Anatomy ›› 2013, Vol. 31 ›› Issue (6): 712-717.

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The finite element analysis of NI-TI anterior screw elasticity fixation on lower thoracic vertebrae

LI Xiao-he1,LI Zhi-jun1,GAO Shang1,WANG Hai-yan1,CAI Yong-qiang1 ,XU Da-chuan2   

  1. 1.Department of Anatomy, Inner Mongolia Medical University, Huhhot 010058, China;  2.Institute of Clinical Anatomy, Southern Medical Univerisity, Guangzhou 501515, China
  • Received:2013-03-10 Online:2013-11-25 Published:2013-12-16

Abstract:

Objective To develop a 3-D finite element(FE) model of NI-TI anterior screw elasticity fixation on lower thoracic vertebrae and evaluate the stress of screw,stick stress. Methods The geometrical model was created by Mimics13.0 based on CT data of T11~12 motion segments from a male patient , which was imported into the Ansys11.0 in order to establish the 3-D FE of anterior screw fixation on lower thoracic vertebrae. The 3D FE models were imported into Ansys11.0 with 500N pressure and 10 Nm moments loaded on the upper surface of T11 to simulate thoracic axial compression,anteroflexion, extension, lateral bending and rotation. The Von mises stress of screws and stick was recorded and input to SPSS11.0 to analyze the difference of different stress distribution of the screws and sticks. Results It was obvious that the Von mises of the screw concentrated on the tail of screws and "U" segment with inferior bearing larger load than superior surface;the lower segment of stick depressed was larger stress. Rotation mayresult in the Von mises concentration on tails of screw and"U"segment,but were lower than yield strength. Conclusions NI-TI anterior screw elasticity fixation on lower thoracic vertebra would not break on usual motion.

Key words:  Lower thoracic vertebra, Anterior fixation, Finite element analysis, Biomechanics

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