Effect of bilateral tenectomy of the tensor veli palatini muscle on soft palate function in horses.

The research aims to understand the effect of a surgical procedure called bilateral tenectomy of the tensor veli palatini muscle on the function of the soft palate and npasopharynx in exercising horses. The results of the study suggest that this muscle is critical in supporting the nasopharynx and regulating its dilation during intense breathing in horses.

Research Objective and Methodology

• The purpose of the research was to examine the impact of bilateral tenectomy, a surgical procedure that removes a specific muscle (the tensor veli palatini), on the function of the soft palate and nasopharynx in horses during exercise.
• To achieve this, researchers conducted tests on five standardbred horses. An instrument called a videoendoscope was used while the horses were undergoing different levels of exertion to measure tracheal and pharyngeal pressures pre and post-surgery.
• The surgery to remove the tensor veli palatini muscle was carried out under general anesthesia, using a transoral approach – surgery conducted through the mouth.

Study Findings

• Post-surgery, the peak inspiratory tracheal pressures increased significantly, and pharyngeal inspiratory pressure also showed a trend toward change, albeit not statistically significant.
• After the tenectomy, the rostral half of the soft palate became unstable and collapsed into the nasopharynx during inhalation, thereby partially obstructing the air passageway.
• However, there was no dorsal displacement (upward shift) of the soft palate in any of the horses during maximum exertion, and the caudal free margin of the soft palate remained below the epiglottis – the flap in the throat which prevents food from entering the windpipe.

Conclusion

• Bilateral tenectomy of the tensor veli palatini muscle did not lead to dorsal displacement of the soft palate in horses, even during maximum physical exertion, but did result in the collapse of the nasopharynx during inhalation.
• The conclusions drawn from the study are that the tensor veli palatini muscle serves to support and dilate the nasopharynx during intense inhalation efforts in horses, by maintaining tension in the palatine aponeurosis – a dense, fibrous connective tissue located in the mouth and throat.