Cystic structures in the guttural pouch (auditory tube diverticulum) of two horses.

This study investigates the presence of cystic structures in the guttural pouches of two horses, which led to pharyngeal compression. Through radiography and surgical exploration, the study diagnoses the conditions and takes steps to facilitate drainage, but the causes or development of the cysts remain unclear.

Investigating Pharyngeal Compression in Horses

This research revolves around two horses that demonstrated symptoms of compression of the pharynx, a part of the throat situated behind the mouth and nasal cavity. The compression was suspected to originate from the pharyngeal wall on the dorsal (rear) side.

• In both horses, there was no patent opening, meaning a functional or accessible entrance, to one of the guttural pouches. These are air-filled sacs connected to the Eustachian tubes in horses.

Radiography and Bacteriologic Culture Findings

The study uses multiple methods to further investigate the conditions of the horses.

• Radiography, an imaging technique that uses X-rays, showed a retropharyngeal opacity or a blockage behind the pharynx, which was obstructing one of the guttural pouches in each horse.
• Fluid samples were taken from the affected guttural pouches to perform bacteriologic culture tests. However, no organisms were identified in the cultures, suggesting the absence of bacterial infection as a cause of the pouch anomaly.

Surgical Exploration of the Guttural Pouch

Surgical exploration was performed on the guttural pouches in both horses to physically ascertain the anomaly.

• In one horse, surgeons found that the lining of the pouch could be easily removed via blunt dissection.
• However, in the second horse, the lining of the guttural pouch was firmly attached and could not be readily removed.
• In both instances, a fenestration or small opening was created between the normal and affected guttural pouches to aid in drainage.

Uncertain Etiopathogenesis

The research concludes without a definitive understanding of the etiopathogenesis – or the cause and development – of the cystic structures in the horses’ guttural pouches.