Numerical analysis of models of the standard TSRH spinal instrumentation: effect of rod cross-sectional shape.
A numerical technique, geometric element modeling and analysis, was used to investigate the effect of the cross-sectional shape of the rod (circular versus square) in three-dimensional models of the standard (dual-rod) Texas Scottish Rite Hospital (TSRH) spinal instrumentation on two biomechanical characteristics (namely, stiffness and the von Mises equivalent stress) of the instrumentation under compressive force and torque, applied separately. The model constraints are the same as those acting on the instrumentation clinically, that is, when it is attached to the vertebrae of the human spine. Furthermore, the magnitudes of the compressive and torsional loadings applied on the model are within the range of those experienced by the spine during normal walking. It was found that use of square cross-sectioned rods leads to better biomechanical performance of the model compared to the case when the rods are circular. This finding points the way to the possibility of using square cross-sectioned rods in the TSRH instrumentation.
Department of Mechanical Engineering, The University of Memphis, Memphis, TN 38152, USA.
Yingwu
Y
Cui
Gladius
G
Lewis
Gang
G
Qi
D019245:Compressive Strength; D003198:Computer Simulation; D017076:Computer-Aided Design; D004548:Elasticity; D019544:Equipment Failure Analysis / Q000379:methods*; D020342:Finite Element Analysis; D006801:Humans; D016268:Internal Fixators; D008954:Models, Biological; D008962:Models, Theoretical; D009038:Motion; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013904:Thoracic Vertebrae / Q000502:physiology / Q000601:surgery; D019415:Torque; D016474:Weight-Bearing