The Development of a Next Generation Total Disc Replacement Prothesis

Author: Ben McCarl

McCarl, Ben, 2017 The Development of a Next Generation Total Disc Replacement Prothesis, Flinders University, School of Computer Science, Engineering and Mathematics

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Low back pain (LBP) has been ranked as the number one disability in terms of years lived with, according to the 2010 Global Burden of Disease study. Furthermore 80% of people will experience low back pain during their lives, with 10% of these eventually developing chronic pain. Once all non-surgical measures have been exhausted there are mainly only two options of surgical prostheses: spinal fusion or a total disc replacement (TDR). All FDA approved TDRs are based on the concept of ball and socket hip replacements, which do not restore the complex biomechanics of the lumbar spine. Nevertheless, they are superior to fusion in terms of allowing a more physiological range of motion. Elastomer core TDRs appear to be the future. A small number of these have been released on to the market with some level of success, however none have yet gained FDA approval. The aim of the project was to commence the early stages of design for a new next generation elastomer core TDR with the aid of finite element analysis (FEA). A parametric study investigating different prototype design geometries was performed to investigate their mechanical response. An extensive literature review summarised relevant studies to the design process including an overview of: the problem of LBP and its financial implications, lumbar spinal morphology, lumbar biomechanics, and a detailed review of both previous and current TDR designs. A novel prototype has been designed. An automated system created in MATLAB has been developed. This software successfully creates XML files that are uploaded into Autodesk Inventor, which changes the desired dimensions of the different template prototype parts. The CAD files are then automatically exported in the correct format so they can undergo FEA in an external software package (Abaqus v6.13 Dassault Systèmes, Providence, RI, USA). The Abaqus FEA simulation process is also automated by a python script that is created concurrently with the generation of the different iterations of the design in MATLAB. The FEA study will investigate the centre of rotation of the prototype when undergoing flexion as an early stage proof of concept of the TDRs customisable design. The project when completed may potentially lead to the development of a commercially viable device.

Keywords: Lumbar Disc Replacement, Total Disc Replacement, Low Back Pain, Costs of Low Back Pain, Total Disc Prosthesis, Lumbar Prosthesis, Design

Subject: Engineering thesis

Thesis type: Masters
Completed: 2017
School: School of Computer Science, Engineering and Mathematics
Supervisor: Assoc Prof John Costi