Brachycephalic obstructive airway syndrome (BOAS) refers to obstructive airway condition that commonly affects short-faced breeds, including the English Bulldog, French Bulldog, Pug, Boxer, Cavalier King Charles Spaniel, Boston Terrier, Griffon Bruxellois, Pekingese and Shih Tzu. These breeds have been bred with relatively short muzzles and noses, and because of this, their airways are compressed causing noisy breathing, snoring and poor exercise tolerance. Some dogs will also vomit or gag when swallowing, or have repeated episodes of regurgitation. Episodes of cyanosis (blue tongue and gums from lack of oxygen) and collapse can occur at times of excitement or stress in some severely affected dogs. Being overweight tends to worsen the problem. If left uncorrected, the condition usually worsens with age and can lead to significant secondary changes, and premature death.

The common anatomical problems seen in brachycephalic dogs include:

  1. Stenotic nares – where the nostrils are too small to allow adequate passage of air making breathing through the nose difficult.
  2. Elongated and/or thickened soft palate – where the soft palate is too long and/or too thick. In these cases the soft palate is excessively long allowing it to sit within the opening of the trachea (windpipe) and thus obstructs normal airflow. The elongated soft palate creates turbulent airflow resulting in the increased respiratory noise we hear in brachycephalic dogs, including snoring.
  3. Everted or swollen laryngeal saccules – These saccules normally sit either side of the floor of the larynx just in front of the vocal folds / chords. In brachycephalic dogs the increased effort of breathing may result in the saccules becoming swollen resulting in obstruction of airflow. Swollen laryngeal saccules is the first stage of collapse of the larynx – a very serious condition.
  4. Tonsillar hyperplasia or enlarged tonsils. This is common in brachycephalic breeds due to chronic inflammation. We usually advise tonsillectomy at the time of airway surgery.
  5. Overgrowth of the nasal turbinate bones – this occurs in some cases and may require additional surgery if breathing is not improved by correction of the above problems.
  6. Tracheal hypoplasia – where the trachea (windpipe) is too small. Diagnosed via chest x-rays. This condition cannot be treated however addressing the other airway issues may be of benefit.
  7. Enlarged tongue – The tongue can be particularly large which contributes to airway obstruction

Other conditions such as hiatal hernia, pneumonia, gastric reflux, tracheal collapse, bronchial collapse, pharyngeal hyperplasia and cardiac disease secondary to increased pulmonary resistance may also occur – especially if corrective treatment is delayed.

Almost all brachycephalic dogs benefit some form of intervention surgery and we recommend that they undergo this prior to 2 years of age. Early correction is most effective at reducing the change of secondary changes and laryngeal collapse, that can be life threatening. They are more comfortable following surgery, breathe more easily and are more active. The best time for most brachycephalic dogs to undergo surgery is between 8 and 12 months of age. It can be performed at the same time of desexing if desired.

Early intervention via corrective airway surgery is strongly recommended.

Our routine assessment of brachycephalic dogs involves:

  • Blood tests are recommended to assess animal’s general health and screen for any other issues.
  • Patients are then pre-oxygenated – given 100% oxygen for 10 minutes prior to anaesthesia.
  • Patients are then anaesthetised to allow visual assessment of the airway.
  • Radiographs of the chest and upper airway are taken to assess tracheal diameter, soft palate thickness and spinal vertebrae.


  • Following assessment, we proceed with surgical correction of the abnormalities. The goal of surgery is to improve airflow.
    1. Soft palate shortening – the elongated soft palate is shortened (staphylectomy).
    2. Stenotic nares – narrow nostrils are opened using a special technique, to widen and deepen the nostrils.
    3. Tonsils are removed in > 90% of cases as they are frequently enlarged and pathologic.
    4. Laryngeal saccules removed if present.
    5. In some cases, palate thinning (folded palatoplasty) may be indicated for thickened soft palates.

If your pet undergoes BOAS surgery here at Erina Heights Vet, most patients will be able to be discharged home the same day. Patients will be sent home with steroid anti-inflammatories, anti-nausea medication and pain relief. Occasionally, some patients will need to be transferred to one of the local emergency hospitals for overnight monitoring. Some patients require oxygen therapy and low doses of sedatives overnight to keep them relaxed. If the swelling does not resolve, a breathing tube may be left in for a few hours, or a temporary tracheostomy will be done, until the swelling in the pharynx subsides enough that the patient can breathe normally. This happens in a small number of cases – and is typically related to the severity of the condition.

In very severe cases, addressing the upper airway issues may not be adequate and the creation of a new permanent opening into the trachea in the neck area (called a permanent tracheostomy) may be the only solution. A permanent tracheostomy is required in less than 1% of cases.

The prognosis is good for young animals. They generally will breathe much more easily and with significantly reduced respiratory distress. Their activity level can markedly improve. Older animals may have a less favourable prognosis, especially if the process of laryngeal collapse has already started.

Overall, the surgery is very successful and improves your dog’s respiratory difficulties, exercise intolerance and their quality of life.

Early correction is the key to a better long term result.

If you would like more information about brachycephalic airway surgery, please book your dog in for a consultation with Dr Melissa Kozaruk – our BOAS surgeon.