DESCRIPTIVE CLINICAL REPORT
Characteristics of palatal instability in Thoroughbred racehorses and their association with the development of dorsal displacement of the soft palate
Article first published online: 7 JAN 2013
© 2012 EVJ Ltd
Equine Veterinary Journal
Volume 45, Issue 4, pages 454–459, July 2013
How to Cite
Allen, K. and Franklin, S. (2013), Characteristics of palatal instability in Thoroughbred racehorses and their association with the development of dorsal displacement of the soft palate. Equine Veterinary Journal, 45: 454–459. doi: 10.1111/evj.12004
- Issue published online: 6 JUN 2013
- Article first published online: 7 JAN 2013
- Accepted manuscript online: 12 OCT 2012 06:07AM EST
- Manuscript Accepted: 3 OCT 2012
- Manuscript Received: 19 JAN 2012
- soft palate;
- palatal instability;
- palatal instability;
- dorsal displacement of the soft palate
Reason for performing study
Two forms of dynamic upper respiratory tract obstruction affecting racehorses that involve the soft palate have been described: palatal instability (PI) and dorsal displacement of the soft palate (DDSP). Observation of DDSP is straightforward in that it is an all or nothing event, whereas observation of PI is subjective and interpretation may vary between clinicians.
The aim of this study was to attempt to characterise PI and to investigate endoscopic features that precede DDSP.
A retrospective study on the endoscopic observations of Thoroughbred racehorses referred for high-speed treadmill endoscopy was performed. Endoscopic observations were reviewed during the last 10 s of the exercise test or the last 10 s prior to DDSP. The degree of axial deviation of the aryepiglottic folds (ADAF), the conformation of the epiglottis, the conformation of the soft palate and the amount of obstruction of the rima glottidis by the soft palate (i.e. soft palate stability) were assessed.
A total of 72 horses were included in this study, of which 7 showed no evidence of PI. Of the 65 horses with PI, 30 (46%) developed DDSP. There were significant associations between the stability of the soft palate, epiglottic conformation and ADAF. Furthermore, development of DDSP was associated with increased severity of PI and ADAF and with changes in epiglottic conformation.
This study has characterised the endoscopic features associated with PI and identified certain characteristics that precede DDSP.
These observations may assist veterinary surgeons in recognising PI and the prodromal signs of DDSP.