الفهرس 
ABSTRACT
Methodology and Finite Element AnalysisOnly 14 pages are availabe for public view
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Abstract
Many people suffer from low-back pain which affect their life quality. Pain can beproduced as a worn disc becomes thin, narrowing the space between the vertebrae.Pieces of the damaged disc may also break off and cause irritation to the nerves indicatingback pain.A major reason of that pain is degenerative disc disease (DDD) as the intervertebraldisc losses its fluid content. This loss of fluid decreases that ability of the intervertebraldisc to act as a shock absorber. As a result, instability in the motion segment occursbecause the disc has lost some of its stiffness.Depending on the severity of a patient’s condition, and after conservative treatmentoptions have been exhausted, a disc replacement surgery (arthroplasty) procedure as analternative to intervertebral disc, an artificial disc serves to replace the damageddegenerated disc. Furthermore restore spacing between vertebrae and relieve thepinched nerve, while still maintaining normal biomechanical movement.Typical complications that are however still observed in some cases of disc implantsinclude: anterior migration of the disc, subsidence (sinking of disc) and lateral subluxation(partial dislocation of a joint). And using keels or grinder to secure fixation of such a discimplant to the adjacent vertebrae could cause vertebrae fracture.To reduce later complications after implantation surgery, using a matching vertebraeendplate geometry artificial implant is a suggestion to immunize surgeons from decidechoosing the artificial disc size, positioning the disc, and cutting through vertebrae inorder to fix the disc. As every patient have a unique vertebra endplate geometry and material properties.Vertebra bone material properties and geometry depend mainly on age, sex andeffect of some bone diseases such as Osteoporosis which decrease bone density and evenchange its geometry.Another approach to improving the TDR implants is to seek new armour materialswith improved performance and prevent disc bulging and wear. Auxetic materials haverecently been hypothesized to exhibit some unique characteristics due to their negativePoisson’s ratio and may provide advantages over conventional engineering materials forcertain applications.A process for artificial disc customization to match the vertebrae end-platesgeometry would be proposed. And a finite element analysis for a motion segment withthe customized artificial disc and for an auxetic material disc would be performed toillustrate the range of motion, the deformation of the polyethylene disc, stress on the vimotion segment, and stress on the polyethylene disc for each disc to illustrate their benefits would be performed.The finite element results yielded that using a patient specific artificial disc would be benefit. Also using auxetic materials in the manufacture of the artificial intervertebral disc would be benefit but at a certain point in the negative range of isotropic Poisson’svalues, the benefits of a negative Poisson’s ratio would begin to be outweighed by the increase in stress and decrease in range of motion. Further future studies will need toindicate the best negative Poisson’s ratio could be used to improve the disc performance.