The effect of laryngoplasty on pharyngeal function in the horse.

This research involved studying the effect of laryngoplasty, a surgical procedure performed to modify the larynx, on the pharyngeal function in horses and ponies. Using various techniques, the researchers found that after the surgery, in some cases, food ended up in the lower respiratory tract, indicating pharyngeal dysfunction and possibly contributing to a chronic post-operative cough.

Research Methodology

• The researchers conducted a study using two ponies in order to examine normal deglutition, which refers to the process of swallowing.
• They employed fluoroscopic techniques and videotape recordings to closely monitor and analyse the process.
• In their experiment, one animal underwent a laryngoplasty procedure, while the other underwent a sham, or fake, procedure for comparison.
• They also studied two clinical cases of horses that had laryngeal paralysis and had been treated with laryngoplasty.

Findings and Observations

• Post-surgery, in the two experimental ponies, it was observed that liquid food was entering the lower respiratory tract. This abnormality was not seen before the surgery.
• In one of the two clinical cases, the horse seemed to swallow solid food normally. However, in the other horse, some food material was found entering the larynx, which is not the intended pathway.
• Such anomalies suggest that there might be post-operative pharyngeal dysfunction, or a problem with the functioning of the pharynx, the part of the throat used in swallowing and breathing.

Suggested Implications

• The researchers suggest that pharyngeal dysfunction might be a consequence of laryngoplasty. This dysfunction, along with over-abduction of the arytenoid cartilage (a pair of small triangular pieces of cartilage in the larynx that influence vocal fold tension), could be factors leading to the chronic post-operative cough that was being investigated.
• These findings imply that laryngoplasty, while correcting one issue (laryngeal paralysis), might introduce another problem (pharyngeal dysfunction), highlighting the need for further investigation and possible refinement of the surgical procedure.