Palatal dysfunction is the most common form of dynamic upper respiratory tract (URT) obstruction affecting racehorses and therefore is of great importance to the horseracing industry. There is an urgent need to develop a robust evidence base in this area of equine sports medicine. The aim of this thesis was to establish the evidence base for the diagnosis, aetiopathogenesis and treatment of dynamic palatal dysfunction and to undertake targeted studies to address key areas. There was poor experimental evidence to fully explain the aetiopathogenesis, which impacted on the efficacy of treatments available. A systematic review of intervention studies showed that decision making for choice of intervention is currently based on inadequate published data, personal experience or anecdote rather than on evidence based data. Many studies were based upon horses without a definitive diagnosis of this condition and there was poor understanding of appropriate outcome metrics for intervention studies. A novel technique of o verground endoscopy was shown to produce diagnostic images of the URT in exercising horses. A comparison of overground endoscopy and treadmill endoscopy showed that dorsal displacement of the soft palate (DDSP) was diagnosed significantly less often during overground endoscopy. A study of overground exercise tests showed that DDSP was more likely to be diagnosed when longer test distances were performed. Certain endoscopic characteristics of the soft palate/epiglottis were shown to be associated with progression of palatal instability to DDSP. The effect of palatal dysfunction on measures ofventilationlgas exchange were evaluated. One form of palatal instability was shown to be detrimental to gas exchange, although this was not as great as the detrimental effect ofDDSP. The value of using race performance as an outcome measure was assessed. Several factors were identified which show that outcome measures such as earnings may not be ideal for assessing intervention efficacy.
|Date of Award||2011|