BIOMECHANICS OF LOW BACK PAIN

Abstract

Low back pain (LBP) is a worldwide health issue with one of the highest ratings among patients as a result of mechanical stress and structural disruptions in the lumbar spine, particularly in the L4-L5 segments. It plays a significant role in the maintenance of a healthy life, and more importantly, it is still challenging to diagnose symptoms accurately due to the multifactorial nature of its causes. Specifically, the success rate of current treatment plans is limited by the inability to reliably link structural abnormalities with symptoms. To better understand the mechanical causes of LBP along with better guidance of clinical decision-making, this project aims to cover the necessity of sophisticated biomechanical modelling. This study is aimed to investigate the biomedical response of lumbar spine FEM (L1-L5 bones) under 3 static loading conditions in ANSYS software. The three distinct loading conditions include pure axial compression (force applied at 0° to the vertical axis on L1), forward bending (force applied at 45° on L1), and side bending (force applied at 20° on L1), while L5 being fixed. The simulations focused on total deformation, equivalent elastic strain, and equivalent (Von-Mises) stress as functions of force from 0 N to 1000 N with the step of 250 N. The results of simulations showed a noticeable increase in all above mentioned biomechanical parameters when exposed to bending conditions compared to pure axial compression in equivalent forces. The most increase is noticed at the 45° forward bending scenario, leading to a non-linear increase at higher force magnitudes. The novelty of this work is in the direct and quantitative comparison of 3 specified loading scenarios in a framework of consistent computational simulations. The comparison and results highlight the significant differences in mechanical demands because of these postures, giving insights on how load direction and different load scenarios can alter the stress and strain in simulation environments.