Introduction

The brachycephalic airway syndrome (BAS) is a well described combination of upper airway disorders in predisposed breeds of dogs.

Therapeutic suggestions for BAS ascend into the thirties of the last century and remained generally unchanged during the recent decades. Most authors focus on the same specific anatomic features if they want to characterize BAS and if they want to explain reasons for the respiratory problems: narrow nostrils, elongated soft palate and everted lateral ventricles.

It is remarkable that all these anatomical structures are located either rostrally or caudally to the nasal cavity itself, but the fundamental eye-catching difference between brachy- and normocephalic dogs is the "missing" or extremely short nose.

We base on the assumption, that one of the very important factors contributing to respiratory distress is the obstruction of intranasal airways due to compression and aberrant conchal growth.

Material and Methods

In a prospective study we examined and treated 80 brachycephalic dogs with severe respiratory insufficiency. Endoscopic examination, CT-Scans and measurement of intranasal airflow resistance (excluding influence of nares and palatum molle) were performed preoperatively to evaluate endonasal obstruction and as a basis for planning the surgical pathway. Endoscopically a diode-laser fibre was used to remove obstructive parts of the conchae thus creating a new meatus nasi ventralis (MNV). Postoperative controls followed with endoscopy, CT-scans and rhinomanometry.

Results

Abnormal conchal growth, obstructing the nasal meatus, was obvious in all dogs. Additionally we found obstructions of the choanae and the meatus nasopharyngeus by parts of the concha nasalis ventralis (CNV) or the concha nasalis media (CNM). With LATE we could resect the blocking structures and succeeded in creating a patent MNV. This was proved with endoscopy and CT-examination. Intranasal airflow resistance was reduced by approximately 50%.

Conclusions

The severe intranasal obstruction we could demonstrate in all dogs of our study allows us to reason that brachycephalic dogs suffer -additionally to the "classical" problems of BAS like stenotic nares and elongated soft palate- from a severe intranasal obstruction with consecutive impaired nasal airstreams and abnormal high airflow resistance.

With CT, endoscopic investigations and measurement of intranasal airflow resistance we could clearly show that conchal tissue obstructs the nasal airway in varying manner and intensity. LATE is an appropriate technique to create a new patent and functional endonasal airway in brachycephalic breeds.