סמינר מחלקה של שחר בנימין - ניתוחי אלמנטים סופיים מבוססי CT של יחידת עמוד שדרה מותני תפקודית אנושית

School of Mechanical Engineering Seminar
Wednesday 28.06.2023 at 14:00

Wolfson Building of Mechanical Engineering, Room 206

CT-Based Finite Element Analyses of a Human Lumbar Functional Spinal Unit

Sahar Benjamin Amsterdam

M.Sc. research under the supervision of Prof. Zohar Yosibash and Dr. Nir Trabelsi
Tel Aviv University, Department of Mechanical Engineering

Low back pain (LBP) is a global concern, causing health problems most of the mature population worldwide and is usually a symptom of lumbar intervertebral disc (IVD) disorders. Patient – specific CT – based finite element (FE) model predicting the biomechanical response of the human spine to daily physiological loads may be useful in clinical decision – making and to improve pre – operative planning of the spine. The aim of this study is to present a methodology for creating a FE model and understand the effect of different parameters on the biomechanical response.

We consider the FEA of the L4-L5 functional spinal unit (FSU), which is the shortest segment of the spine, formed by two adjacent vertebrae, IVD and ligamentous tissues. A 3D model of the FSU was segmented from CT scans, the IVD was model as a connecting tissue between the vertebrae and seven most important ligaments were included at their anatomical attachment points, focusing on the accuracy of the model’s characteristics so to comply with geometrical data from literature. Based on a literature survey, CT – based inhomogeneous elastic properties were assigned to the vertebrae and hyperelastic anisotropic properties were assigned to the IVD. To study the FSU behavior, four daily movements were defined as boundary conditions and a compressive follower load (FL) was applied to mimic the intradiscal pressure loads in the spine.

In this study, we define a methodology for creating patient – specific CT – based FE model of the FSU. Variety of tests were performed to investigate the influence of the model assumptions on its mechanical response.  The convergence of the results has been tested on several cases to ensure that the mesh has no significant effect on the FE results. In addition, the sensitivity of the material properties was investigated by comparing the FSU mechanical response with different material models for the vertebrae and the IVD. This study contains helpful fundamental information for creating a spinal FE model towards improving spinal healthcare.

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