Photoelastic and Finite Element Stress Analysis of the Gap between the L4 and L5 Vertebrae

Abstract

The purpose of this study was to analyze the stresses on the intervertebral disc between vertebrae L4 and L5 when a compressive load is applied on vertebra L4 using the photoelasticity transmission technique and the finite element method. Nine photoelastic models were used and were divided into three groups. Each group was formed by three models, according to the localization of the sagittal cut on vertebrae L4-L5. Simulation was carried out using a load of 23 N. The fringe orders were assessed by points close to the edge of the intervertebral disc using the Tardy compensation method. The analyses using the photoelasticity technique and the model of the finite elements showed that the stress generated by the vertebrae on the intervertebral disc was higher in the posterolateral region. Thus, this region is more susceptible to pathologies such as hernia and disc degeneration.

Isotropic Liquid Crystal Elastomers as Exceptional Photoelastic Strain Sensors

“…Examples of previous studies to have used photoelastic methods to study soft biological tissues include Hirokawa et al and Kawada et al, who studied strain in ligaments. , Additionally, Fakhouri et al, and Doyle et al . used photoelastic experiments in conjunction with FEA analysis to respectively study the gap between the L4 and L5 vertebrae and models of abdominal aortic aneurysms. , Lastly, Tomlinson et al. demonstrated using photoelastic materials as surrogate biological tissues in the study of tissue biomechanics .…”

“…demonstrated using photoelastic materials as surrogate biological tissues in the study of tissue biomechanics . Going forward, photoelastic techniques could aid in the regulatory approval of biomedical devices, comparing the behaviors of natural and synthetic biomimetic materials in quasi-static and dynamic testing and also in verifying the accuracy FEA models of biomedical devices that are fabricated from smart and multifunctional materials with complex mechanical behvaviours. ,, …”

“…17,18 Additionally, Fakhouri et al, and Doyle et al used photoelastic experiments in conjunction with FEA analysis to respectively study the gap between the L4 and L5 vertebrae and models of abdominal aortic aneurysms. 9,19 Lastly, Tomlinson et al demonstrated using photoelastic materials as surrogate biological tissues in the study of tissue biomechanics. 11 Going forward, photoelastic techniques could aid in the regulatory approval of biomedical devices, comparing the behaviors of natural and synthetic biomimetic materials in quasi-static and dynamic testing and also in verifying the accuracy FEA models of biomedical devices that are fabricated from smart and multifunctional materials with complex mechanical behvaviours.…”

“…11 Going forward, photoelastic techniques could aid in the regulatory approval of biomedical devices, comparing the behaviors of natural and synthetic biomimetic materials in quasi-static and dynamic testing and also in verifying the accuracy FEA models of biomedical devices that are fabricated from smart and multifunctional materials with complex mechanical behvaviours. 9,19,20 However, one of the major challenges for employing photoelastic methods is choosing materials with appropriate physical properties. For reflection photoelasticity, low modulus (high compliance) materials with large strain-optic coefficients are required.…”