Cross-sectional area of the aditus laryngis and rima glottidis before and after transection of the left recurrent laryngeal nerve in the horse.

This study investigated the change in size or cross-sectional area of parts of the horse’s airway, specifically the rima glottidis and the aditus laryngis, before and after surgically cutting the left recurrent laryngeal nerve. The results showed a significant reduction in the area and width of these structures after the surgical intervention.

Research Methodology

• The researchers first measured the ventral-to-dorsal height of the rima glottidis from lateral pharyngeal radiographs. This was done after correcting for magnification to ensure accurate measurements.
• Endoscopic photographs of 5 horses were taken before and after transection of the left recurrent laryngeal nerve. This nerve was cut in a surgical process referred to as a neurectomy.
• The rima glottidis height was utilized to accurately enlarge the endoscopic images.
• A computerized digitizer was used to measure the areas of the rima glottidis and aditus laryngis in these enlarged images.

Research Findings

• Before the neurectomy, the mean area of the aditus laryngis was 1,908 mm2 and the mean area of the rima glottidis was 1,198 mm2. However, after the neurectomy, these areas significantly reduced to 1,346 mm2 and 805 mm2 respectively.
• Similarly, the mean width of the rima glottidis reduced from 31mm before the neurectomy to 20mm after the procedure.
• Though the areas and widths significantly shrunk after the procedure, there were no significant differences in the heights of the rima glottidis before and after the neurectomy.

Conclusion

These findings suggest a significant anatomical alteration in the horse’s airway after a neurectomy. This could imply changes to the horse’s respiratory function following such a surgical procedure, which necessitates further investigation.