Laryngotracheoscopy in brachycephalic and mesocephalic dogs:anatomical comparison and development of a conservativetechnique for training on cadavers

Abstract

Laryngotracheoscopy is a crucial tool in both clinical practice and the diagnosis of respiratory conditions, particularly in brachycephalic dogs, which are prone to anatomical airway abnormalities. This study aimed to introduce a technique for preserving canine cadavers for laryngo-tracheoscopy training and to explore anatomical differences between brachycephalic and mesocephalic dogs. We used a total of 30 cadavers, evenly split between the two morphological groups, in compliance with the ethical guidelines set by CONCEA. We employed a preservative solution composed of curing salts and 5% glycerinated ethyl alcohol, administered through thoracic aortic cannulation, then stored the cadavers under vacuum at 4 °C for up to 120 days. The cadavers underwent laryngotracheoscopy both before and after storage to assess coloration, malleability, and the integrity of the anatomical structures. Anatomical alterations, such as laryngeal saccule eversion and tracheal stenosis, were also examined. After 90 days of preservation, 100% of the cadavers retained coloration and malleability akin to fresh cadavers, proving suitable for laryngotracheoscopy training. However, after 120 days, only 72.2% maintained the desired tissue texture and coloration. Noteworthy was that 93.33% of brachycephalic dogs showed a reduction in glottic lumen compared to mesocephalic dogs, which presented more uniform and less edematous structures. Furthermore, the apex of the epiglottic cartilage in brachycephalic dogs was more rounded in contrast to the more pointed appearance in mesocephalic dogs. In conclusion, the preservation technique proposed here is effective for maintaining cadavers for laryngotracheoscopy training up to 90 days and facilitates detailed anatomical comparisons between brachycephalic and mesocephalic dogs. This technique supports the training of professionals in managing respiratory alterations in these breeds, promoting both ethical and cost-effective practices.