UBC Theses and Dissertations
Development of a functional spinal unit for evaluation of sports and automotive protective equipment Fonseca, Graham
Globally, millions of spinal cord injuries (SCIs) and traumatic brain injuries (TBIs) occur annually [WHO, 2013], [Dewan, 2019], most commonly in vehicular crashes, falls and sports [Cripps, 2011], [Singh, 2014]. These injuries lead to paralysis, a decrease in mental health [DeVivo, 1991], [Losoi, 2016], and/or financial hardship [McGregor, 1997], [Lenehan, 2012]. SCIs and TBIs are most likely to occur in men [Singh, 2014], [Nguyen, 2016], [CDC, 2016], at the C4-C5 level [Prasad, 1999]. As SCIs and TBIs have a high occurrence and dire health consequences, it is crucial that they are prevented. Safety equipment meant to prevent head and neck injuries, such as helmets and seatbelts, are evaluated using anthropometric test devices (ATDs). Unfortunately, there is no ATD neck that is biofidelic for the multiplane loading that occurs in real-world scenarios [Nelson, 2010]. As such, the aim of this research was to take a step towards creating a biofidelic omnidirectional surrogate neck for the evaluation of these safety devices. This first step was to design and construct an anatomically accurate sub-axial functional spinal unit (FSU) that produced a repeatable biofidelic response in quasi-static flexion-extension (FE), axial rotation (AR), lateral bending (LB), and coupled motion. This research was carried out in three main phases. The first was to design, construct and test synthetic sub-axial cervical segments in AR and FE to obtain a basic understanding of their inherent complex motion. The second was to perform compression and tension testing on potential surrogate intervertebral disc and ligament materials, respectively. This was to identify the structural properties of the components in order to select biofidelic materials, when compared to published cadaveric results, for use in the final FSU. In the final stage, anatomically accurate C4 and C5 vertebrae were constructed from the CT scans of a 31-year-old male. An FSU was built using the previously selected soft tissues and when compared to published cadaveric results, showed acceptable biofidelity in AR, FE, LB and coupled motion. The process of constructing this biofidelic FSU will inform future construction of a full surrogate neck to be used in the testing of head and neck safety equipment. Supplementary materials available at: http://hdl.handle.net/2429/77434.
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