Die ontwikkeling van 'n pasklaar-vervaardigde kunsmatige intervertebrale skyf-implantaat

[摘要] ENGLISH ABSTRACT: Current technology enables researchers to identify a broad spectrum of opportunities in thebiomedical industry to develop new and innovative products. Imaging technology, such asComputerised Tomography (CT) scanners or Magnetic Resonance Imaging (MRI) scanners, allowdoctors to visualise a patient's internal organs and bone structure in high quality three-dimensionalimages.Rapid Prototyping Technology (RPT) can already produce high quality complex parts, such asconcept parts for the automobile industry and medical models for preoperative planning. These partsare divided into thin layers and manufactured layer by layer. At the same time the layers are joinedtogether to produce the desired part.Generic artificial intervertebral disc implants already exist. However, these discs are only available instandard geometrical dimensions. The possibility of using imaging technology and RPT to design andmanufacture a customized, patient specific implant will be investigated.A simple design (ball and socket) is used to illustrate the design process of a customized disc. Itshould be noted that this project does not attempt to design a new artificial intervertebral disc implant,but rather describes the design process.The research question is: How accurate can the customised disc implant's inverse geometry representthe geometry of the vertebrae's endplates?A preliminary research was done and the results were used to calculate the sample size for this study.A cadaver, provided by Stellenbosch University's Faculty of Health Sciences' Anatomy andHistology Department, was CT scanned. The L4- and L5-vertebrae were dissected, cleaned andmeasured using a photogrammetry measuring machine.Meanwhile, the data gathered from the CT scan is used to design the customised disc implant. Thedisc is manufactured from Ti6Al4V using a RPT technique called Direct Metal Laser Sintering. Afterthe part is manufactured it is also measured using a photogrammetry measuring machine.The photogrammetry data from the vertebrae and the manufactured customised disc implant arecompared, analysed and a hypothesis is formed. It can now be determined, with a certain degree ofconfidence, how accurate the customised disc implant's geometry can represent the geometry of thevertebrae's endplates.The design of a customised disc implant demands many work hours from a qualified engineer ordesigner, which in turn increases the production costs. This study describes a user-friendly programwhich will semi-automate the design process. Only limited input from the physician will be required.This program will decrease design time, which will have a direct effect on the production costs. Themanufacturing costs are investigated as well.The results from this study indicates that it is possible to design a customized prosthetic, with the helpof a custom disc generator, within 27 minutes. The customized disc can then be manufactured with anaccuracy of 0.37 mm using rapid prototyping.

[发布机构] Stellenbosch University