Brachycephalic Obstructive Airway Syndrome


*For a quick VIDEO REFERENCE about this syndrome, please scroll to the bottom of this page.*


What is Brachycephalic Obstructive Airway Syndrome?

Brachycephalic obstructive airway syndrome (BOAS) refers to a group of conditions that arise from the anatomical conformation of short nosed dogs and cats, known as brachycephalic breeds.

Brachycephalic breeds have intentionally been bred to shorten the length of their noses, and thus suffer from the consequential side effects of this breeding. Breeds with flattened noses have a compacted skeleton, resulting in multiple anatomical malformations to the breathing passages. Common examples of Brachycephalic dog breeds include Pugs, French Bulldogs, English Bulldogs, Pekingese and Boston Terriers. Persian cats are also a brachycephalic breed.


Conditions that comprise BOAS

Stenotic Nares

Brachycephalic breeds have stenotic (narrow) nares (nostrils) and nasal passages. This results in increased resistance to airflow through the nares and nasal passages resulting in an increased effort to breathe. This increased negative pressure in the back of the throat in turn results in stretching of the soft palate.

Elongated Soft Palate

The end of the palate, known as the soft palate, is often excessively lengthened and thickened in brachycephalic breeds. This fleshy tissue is drawn into the larynx during inspiration and vibrates resulting in the classic snore or “stertor” made by brachycephalic breeds. This tissue can block the larynx reducing airflow to the lungs.

Everted Laryngeal Saccules

Laryngeal saccules are sacs that are positioned just in front of the vocal folds in the larynx. The lining of the saccules evert (protrude) into the larynx due to the increased negative pressure generated by brachycephalic breeds during inspiration. These then block the opening to the airway further reducing airflow to the lungs.

Laryngeal Collapse

The larynx is a specialised structure that represents the opening of the trachea (windpipe). It allows air to flow into and out of the trachea and lungs during inspiration and expiration. It also prevents food and water from entering the trachea when swallowing and the vocal folds within the larynx allow dogs and cats to vocalise.

Laryngeal collapse is an advanced form of brachycephalic airway syndrome that results from weakening of the cartilage that supports the larynx. Without this support, the larynx collapses. This reduces airflow, or completely prevents airflow to the lungs.

Gastrointestinal Problems

Brachycephalic breeds may also develop problems with the gastrointestinal system. These may include regurgitation and vomiting.


Diagnosis of BOAS

All brachycephalic breeds suffer from some degree of BOAS. The most common clinical history is noisy breathing, particularly on inspiration, with varying levels of respiratory distress. Less commonly, dogs may present due to acute collapse following exercise or over-activity. Brachycephalic breeds may also present due to frequent regurgitation or vomiting.


How is BOAS diagnosed?

A diagnosis of BOAS is suggested by the signs a cat or dog shows. However, a definitive diagnosis of BOAS is made during an upper airway examination under general anaesthesia. This allows the anatomical malformations to be observed directly.


Surgical Treatment

Brachycephalic obstructive airway syndrome is treated with partial resection of the soft palate (staphylectomy), nares and laryngeal saccules. These procedures reduce the amount of tissue blocking the flow of air to the lungs and improve the quality of life of BOAS patients. Unfortunately, a complete cure for this condition is not possible. Subsequently, a mild degree of noise while breathing may be retained.


Important Details Regarding Surgery

This procedure requires specialized training to be able to perform.  The Vets at Maraboon Veterinary Surgery have spend ALOT of time learning and perfecting this surgery.  Although all surgery and anesthetics contain an inherit risk it is important to highlight the possible risk associated with this procedure.  Although these risks are there no matter who performs procedure, the more experience the surgeon ha,s the more prepared at minimizing and dealing with complications.  

  • 80% of patients will go home the same day and other than being a little wobbly from aesthetic there will be no noticeable signs.  Majority of these dogs will have noticeable improvement with their breathing the very next day after surgery, and continue to improve over the next 1-3 months.
  • 15% complication rate postoperatively of being more noisy (temporally for 1-2 weeks), need additional medications (such as sedatives, antibiotics, other) and possibly increased rechecks with Veterinarian (these may incur some small extra costs)
  • 5 % risk of more severe complications including; require additional surgery (as insufficient clinical improvement), hospitalization afterwards with ICU care and oxygen.  If these complications arise, they can be life threatening. This will involve additional costs to owners.  This is similar at all vet clinics unfortunately, despite all precautions taken to avoid.
  • 1% risk of aesthetic or surgical death, unfortunately all anaesthetics and surgeries have serious risks potential, however this surgery is higher than average surgery.  This is reported in dog with extremely severe underlying airway disease and thus higher risk.  These animals will be identified and risks discussed with owner at your Pre-surgical consultation.
  • It is STRONGLY RECOMMENDED to do this procedure on young healthy dogs preferably under a year of age as they do not have same increased risks.

How much does surgery cost?

Corrective surgery alone - $1600-$1850

Corrective surgery with another procedure - $1350-$1600 + cost of other procedure (e.g. desexing).  Benefit of only one anaesthetic

Costs include:

  • Anaesthetised upper airway assessment
  • Day care monitoring with dedicated vet and nurse
  • Post op visit 3 days post operation
  • All related surgery fees
  • Take home medications following surgery
  • Excludes the cost of initial consultation ($115)
  • Excludes additional fees associated with surgery complications (notes above) 

Information courtesy of QLD Veterinary Specialists

To book your initial pre-operative appointment or to find our more information about this condition and surgical procedures, please click here

Informational Videos