Author: Joseph Mwiseneza
Mwiseneza, Joseph, 2018 Investigation of loading techniques to create thoracolumbar burst fractures, Flinders University, College of Science and Engineering
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Thoracolumbar burst fracture is one of the spine fractures that is mainly found in people falling from high heights, especially young active people aged between 14 and 24 years who participate in activities requiring to jump from a height of more than 2 m and landing on their feet or buttocks. These fractures often lead to problems including medical conditions, inability to participate in social activities or cessation of employment leading to financial crisis. Many studies have been performed to investigate a proper treatment method; however, there is no consensus yet. The present study was directed with the first aim of investigating loading techniques to create reproducible thoracolumbar burst fractures and with a second aim of comparing the results with clinical cases examined in the literature review. Twenty-four sheep specimens were divided into three groups of eight, where each group represented different spinal levels (T12-L1, T12-L2, and T13-L2). The T12-L1 and T13-L2 groups had a single unconstrained vertebra while the T12-L2 group had two unconstrained vertebrae. All the specimens were struck axially by a high-speed impact drop tower. The results were analysed by observing the nature of the fractures produced and matching them with their x-ray images, to determine where the fractures initiated, and the energy and forces used for their production. The results were validated by comparing with the findings from the literature. The maximum energy used was 140 joules while the fracture force across all groups varied between 2369 N and 6506 N. The results from the T12-L2 group showed six burst fractures at T13 and two burst fractures at L1. The group of T12-L1 showed six burst fractures at T13, while the T13-L2 group produced five burst fractures only. The rest of specimens in the single unconstrained vertebrae groups had some fractures, but these were not classified as the burst fractures. A univariate ANOVA revealed no significant difference in fracture load between each group (p = 0.194). To gain further insight into the results, the fracture load was normalised by the impact energy, and the impact energy and disc area, both of which were not significantly different (p > 0.205). Some of the limitations of this experiment include the height of the drop tower, the loadcell that was only designed for axial impact, the sheep specimens grew up in different environments and had an unknown age, and no human specimens were available for this study to compare the results with.
This study has shown that by testing multilevel FSU (T13-L1), the chance of fracture is higher in T13 than L1 and by comparing with the literature, the required force to create Thoracolumbar burst fracture was found to be higher in sheep than human spines. This study should be developed further using human specimens with an increased height of the drop tower, using a 6DOF loadcell and a camera to observe the motion of bone fragments in the spinal canal.
Keywords: Investigation, thoracolumbar, burst fracture
Subject: Engineering thesis
Thesis type: Masters
Completed: 2018
School: College of Science and Engineering
Supervisor: Associate Professor John Costi