The Biomechanical Effect Of Human Weight On Spinal Facet Joints Using Finite Element Analysis

Mohammad, Raed Ali (2016) The Biomechanical Effect Of Human Weight On Spinal Facet Joints Using Finite Element Analysis. Masters thesis, Universiti Teknikal Malaysia Melaka.

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Abstract

Many important medical associations define obesity as a disease. Being overweight or obese is a serious disorder that affects human spine. Obesity is a contributing factor to back pain due to changing for the mechanical properties as a result to the over loading. Hence, being overweight or obese can significantly contribute to symptoms associated with osteoarthritis (OA), facet joint arthritis, degenerative disc disease (DDD), spinal stenosis, and spondylolisthesis. However, the facet joint behavior regarding the body weight effects under separate loadings or the responses to the compressive loads in the discs need to be identified. Moreover, using cadaveric specimens in biomechanics testing of the lumbar spine restricted with a difficulty in acquiring the disc pressure, bone strain and facet joint contact pressure. While, simulation model looks into all of these disadvantages. Thus, the goal of the current study was to develop a method to simulate the biomechanics of the lumbar spine, and to delve into the effect of obesity on the intervertebral discs and facet joint in addition to provide the system analysis of the spine between multi body weights. The finite element analysis results will highlight significant differences if the model adopted is performed under different material properties, geometries, loading modes or other conditions. A process is currently in use to transform a CT scan of a lumbar spine into a simulation model. The process includes changing the CT scan to a geometry file and creating a mesh of the bone and soft tissue, and assigning material properties to each bone element based on the bone density. Lumbar spine models was developed and verified with previous studies. The finite element model was subjected to follower compression load of 500 N, 800 N and 1200 N to represent the load case of normal, overweight and obese with a combination of pure moments of 7.5 Nm in flexion and extension. The results highlight the fact that in all loadings case of (normal, overweight and obese people), there are high distributions of stress in both L4 and L5 and so on the intervertebral discs. Increasing the human weight was in turn increasing the nucleus pulposus pressures and annulus fibrosus stresses. Intradiscal pressures in the nucleus pulposus were increased more noticeably with flexion than with extension. With regard to the facet joint forces, flexion resulted in a larger facet force in the superior facet joints· than that in the inferior facet joints at the same level and in extension was 21% more than flexion motion, and both of them were in increment at over and obese person weight. Moreover, it also appeared that the influence of the magnitude of normal body weight loads on the facet force was less important than that due to overweight and obese weight. This model also can serve to simulate the implants performance including the total disc replacement and fusion techniques.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Human mechanics, Biomechanics
Subjects: Q Science > Q Science (General)
Q Science > QP Physiology
Divisions: Library > Tesis > FKM
Depositing User: Nor Aini Md. Jali
Date Deposited: 13 Jul 2017 07:42
Last Modified: 13 Jul 2017 07:42
URI: http://eprints.utem.edu.my/id/eprint/18642
Statistic Details: View Download Statistic

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