Photoelastic analisys in the lower region of vertebral body L4

OBJECTIVE To analyze the shear forces on the vertebral body L4 when submitted to a compression force by means of transmission photoelasticity. METHODS Twelve photoelastic models were divided into three groups, with four models per group, according to the positioning of the sagittal section vertebrae L4-L5 (sections A, B and C). The simulation was performed using a 15N compression force, and the fringe orders were evaluated in the vertebral body L4 by the Tardy compensation method. RESULTS Photoelastic analysis showed, in general, a homogeneous distribution in the vertebral bodies. The shear forces were higher in section C than B, and higher in B than A. CONCLUSION The posterior area of L4, mainly in section C, showed higher shear concentrations, corresponding to a more susceptible area for bone fracture and spondylolisthesis. Economic and Decision Analyses - Development of an Economic or Decision Model. Level I.