The effects of body fat percentage on inter-vertebral spinal mobility control from hyperextension spinal orthoses
Hyperextension spinal orthoses are common modalities in treating vertebralfractures. Their objective is to retain the spine in a hyperextended position tooffload the fractured vertebra(e) and allow healing. To date, accurate insight intothe efficiency of hyperextension spinal orthoses is absent. In particular, publishedstudies have focused on the efficiency of these orthoses in restricting the gross orinter-vertebral spinal range of motion, rather than on their efficiency in retaining thespine in a hyperextended position. Also, in the literature, an increase in body-fatpercentage(obesity) is assumed to reduce spinal orthoses efficiency, although thishas not yet been investigated.Therefore, this thesis aimed at filling these gaps by conducting an investigation tomeasure the efficiency of the two main designs of hyperextension spinal orthoses(Jewett and CASH) in retaining the spine in a hyperextended position whilst wornby normal-body-mass and obese participants. This, however, was preceded bytwo preliminary studies where: 1) X-ray practices were optimised to produce spinalimage of suitable quality for inter-vertebral mobility measurements from the lowestpossible dose; and 2) different inter-vertebral mobility measurement methods weretested to identify the one with highest accuracy and reliability (which was theadjusted superimposition method).The findings from these two preliminary studies were essential to fulfilling the aimof this thesis. Specifically, after recruiting two groups of eight healthy participantseach (normal-body-mass and obese), the optimised X-ray practices were used toacquire six X-ray images of each participant's spine in three conditions (without,and with Jewett and CASH orthoses). Then, inter-vertebral mobility was measuredusing the adjusted superimposition method.The results showed that, although statistically insignificant (P>0.05), both Jewettand CASH orthoses demonstrate higher efficiency whilst worn by normal-bodymassgroup, and that Jewett orthoses tend to be more efficient than CASHorthosis in both normal-body-mass and obese groups.
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