The influence of preload application for vertebra segment in finite element modelling

The awareness of the spine lumbar kinematics is one of the crucial knowledge to various aspects of clinical application such as diagnosis, treatment and surgical intervention. Continuous evolution of affordable and powerful computers has increased the complexity of the finite element models to assist in understanding the behavior in musculoskeletal systems. Most of the studies carried out under a certain method loading condition either axial load or follower load to represent the upper weight of the human body. Therefore, the aim of this study was to evaluate the influence of axial preload and follower preload towards the biomechanical behavior of vertebral segment. A ligamentous of L4-L5 lumbar vertebral segment finite element model was generated from a healthy male of the computer tomography (CT) scan image data. The model was verified and in agreement with the experimental studies. The axial preload and follower load possessed significant differences in range of motion (ROM), intradiscal pressure (IDP) and von Mises stress (VMS) on the annulus fibrosus for flexion and extension loading activities. This is because the stress distribution on the annulus ground and the nucleus pressure seems to be influenced by the ROM. Based on the results, the appropriate loading condition could be crucial in finite element analysis of lumbar spine.