Histological Evaluation of the Soft Palate in Dogs Affected by Brachycephalic Obstructive Airway Syndrome

Introduction
Airway obstruction in brachycephalic dogs occurs as the shortening of the skull is not matched by the associated soft tissues. This leads to an excessive soft tissue obstruction within the nasopharynx and oropharynx with the soft palate being both overlong and thick compared to normal dogs. Increased thickness of the soft palate was the most significant difference between brachycephalic and dolichocephalic breeds when comparing sagittal CT sections of the pharynx. Previous studies have histologically described the caudal edge however the composition of the thick portion of the soft palate is not known.

Methods and Materials
The soft palates from four control dogs (2 greyhounds and 2 mixed breeds) euthanased for reasons other than respiratory disease were removed. Specimens were also preserved from brachycephalic dogs (4 English bulldogs and 3 French bulldogs) undergoing a folded-flap palatoplasty for surgical correction of a long and thick soft palate. All the clinical cases were BOAS Grade 3 prior to surgery. The excised tissue was fixed in buffered 10% formalin and qualitative histological evaluation performed on each section stained with hematoxylin and eosin (H&E).  [...]