Chinese Journal Of Clinical Anatomy ›› 2012, Vol. 30 ›› Issue (3): 333-336.

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The finite element analysis of Aerofoil shape memory alloy fixation instrument for surgically treating spondylolysis

ZHU Li-xin1, WANG Jian1, CAO Yan-lin1, FAN Wang-ju1, YU Guo-ji2, ZHANG Xi-bing1, YE Wen-ming1   

  1. 1.Department of Orthopedics, Zhujiang Hospital, Southern Medical University,Guangzhou 510282, China;2.School of Chemical Engineering and Technology,Tianjin University, Tianjin 300072, China
  • Received:2011-10-27 Online:2012-05-25 Published:2012-06-06

Abstract:

Objective To establish the three-dimensional finite element model (FEM) with the bilateral pars defect and reconstruct by AEROFOIL fixation. Methods According to spiral CT scan images of 0.625 mm thickness,finite element model of lumbosacral vertebrae was established using Mimics10.01, Geomagic studio12.0, HyperMesh 10.0 and Abaqus10.1 software. Moreover, it's validity had been verified and then imported the AEROFOIL fixation. The reconstructed model was analyzed under 500N pressure loading on the upper surface of L1, and 7.5Nm torque loading for simulating axial compression and flexion, extension, lateral bending and rotation. The Von mises stress of fixation were recorded and analyzed. Results It showed that high stress concentrated at the bottom part of the swings, especially at the junction of the swings and the U-shape base. Extension and axial rotation motion resulted in breakage of the AEROFOIL fixation. Conclusions Improving Nitinol material quality and process standards and suitably prolonging the need for external bracing are necessary for reducing the higher risk of fracture on fixation devices.

Key words: Lumbosacral spine, Spondylolysis, Fixation devices, Finite element analysis

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