34th Annual Scientific Meeting proceedings

Objectives:

Extreme brachycephalic breeds are more prone to developing brachycephalic obstructive airway syndrome (BOAS) and may show laryngeal alterations depending on the severity of BOAS. BOAS is classified into four degrees on the basis of the syndrome's components, and its clinical presentation is progressive. Chronic airway obstruction can result in laryngeal collapse (LC), which is classified into three degrees of severity. This study aimed to analyse the cuneiform process of the arytenoid cartilage in brachycephalic dogs through histopathological evaluation and to correlate the histopathological characteristics with the severity of BOAS and the degree of LC.

Methods:

Arytenoid cartilage samples were obtained from 25 brachycephalic dogs that showed LC and underwent unilateral or bilateral cuneiformectomy between 2021 and 2023. Each cartilage sample underwent two histopathological evaluations: morphological (haematoxylin and eosin staining) and metachromatic (toluidine blue staining). On the basis of these evaluations, a morphological score, a metachromatic score, and a final score were determined.

Results:

All analysed tissues showed degenerative changes in the arytenoid cartilage. Although the degree of degeneration varied, it was present across all degrees of BOAS and LC severity. Most of the cartilages were classified as mildly (48%) or moderately (44%) degenerated. No significant correlation (P > 0.05) was observed between degeneration scores and the severity levels of BOAS and LC.

Conclusions:

Brachycephalic dogs with BOAS and LC show chondromalacia. These alterations do not appear to correlate with the degree of brachycephalic syndrome or the severity of LC.

FINANCIAL SUPPORT: São Paulo Research Foundation 2023/08910-8