What is Brachycephalic Obstructive Airway Syndrome (BOAS)?

BOAS is the term used to identify the effect that a shortened head has on the passage of air through the nose or mouth into the main airway (trachea). Restriction of air intake results in variable clinical signs that include snoring, snorting, constant panting, exercise intolerance, episodes of collapse, heat stroke, and regurgitation. The clinical signs are often accepted as “normal” for these breeds.

All brachycephalic breeds have the following abnormalities to varying degrees:

• Stenotic (narrowed) nares/nostril openings
• Elongated soft palate
• Hypoplastic (narrowed) trachea (main airway to lungs)

Brachycephalic Breeds are those dogs with a shortened muzzle, which include but are not limited to: French bulldog, pug, Boston terrier, English, Australian, and American bulldog, cavalier King Charles spaniel, shih tzu, Pekingese, Japanese chin, boxer, and mastiff breeds.

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What can be done?

• Alarplasty: Widens the nostril openings to allow more air to enter the nose.

• Staphylectomy: The soft palate extends from the roof of the mouth towards the opening of the airway (larynx). When excessively long, it covers the opening and stops airflow entering the trachea (windpipe). The surgery shortens the soft palate, enabling entry of air.

• Hypoplastic trachea (windpipe): A narrowed windpipe is equivalent to breathing through a straw. The tracheal size can be estimated based on radiographs. It is important to gauge how badly affected a dog is, as it is related to prognosis. 20% is considered normal.

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Why perform upper airway surgery early?

Obstructive upper airway disease results in excessive respiratory effort. This exposes the larynx to constant negative pressure, which, without early intervention, weakens the cartilage and leads to eventual laryngeal collapse. Laryngeal collapse is irreversible. The only treatment for severe laryngeal collapse is permanent tracheostomy.

The benefits of early surgical intervention include:

• Reduced respiratory effort

• Delayed onset and progression of laryngeal collapse

• Lesser requirement for permanent tracheostomy as a salvage procedure

• Prolonged lifespan.

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Brachycephalic breeds and gastrointestinal disease

Brachycephalic dogs also have a high prevalence of gastrointestinal tract problems. Clinical signs include:

• Unprovoked gastroesophageal reflux/vomiting (significant risk for aspiration pneumonia, oesophageal inflammation)
• Intermittent diarrhea without dietary change
• Underweight despite a healthy appetite
• Choking/gagging; bringing up foam
• Nasal discharge

Assessment of their degree of reflux is best evaluated with an oesophageal pH probe, as these events are difficult to reliably quantify in dogs. The device uses a small 2mm probe placed through the nose into the oesophagus. Stomach content is acidic, and the pH monitor facilitates detection of this acidic content.

The two major components of gastrointestinal disease are:

• Oesophageal hiatal rim malformation
• Inflammatory bowel disease (IBD)

Oesophageal hiatal rim malformation

Some brachycephalic dogs have a malformation in the opening (hiatus) of the diaphragm where the oesophagus passes into the stomach. This creates an enlarged opening, which allows the stomach to slide forward, resulting in reflux and regurgitation. This can appear as burping, lip licking, or retching without an active abdominal effort.

This malformation can be reconstructed, reducing its size and restoring the normal anatomy. With the oesophagus secured in a normal position, the stomach will not slide into the chest, significantly reducing regurgitation frequency. If this is suspected and confirmed, this surgery is performed following recovery from airway surgery.

Inflammatory bowel disease (IBD)

IBD is inflammation of the intestinal tract, which inhibits normal absorption and passage of food and can result in vomiting, diarrhea, and poor weight gain. Diagnosis is by biopsy. There is no cure for IBD; however, it can be controlled through diet modification and medication. Controlling IBD in brachycephalic dogs improves their overall outcomes of airway and hernia surgery.

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What to expect after surgery

• Hospitalisation - Your pet will stay overnight, to ensure pain management, monitor their initial recovery, and address any post-surgical concerns with our 24/7 on-site team. They can be discharged when they eat well without signs of vomiting.
• Recovery Period – Your dog will require a 2–3-week recovery period post-surgery.
• Swelling and Inflammation – Mild swelling of the surgical site is normal and usually resolves within a few days.
• Coughing or Gagging – Some dogs may experience mild coughing or gagging as they adjust to their new airway anatomy.
• Restricted Activity – Exercise should be limited for at least two weeks to allow proper healing.
• Dietary Adjustments – Soft food (canned dog food rolled into “meatballs” is recommended temporarily to ease swallowing.
• Monitoring for Complications – Watch for signs of breathing difficulties, persistent coughing or persistent vomiting/regurgitation, and contact your veterinarian if these occur.

With appropriate treatment and management, most dogs recover well from a brachycephalic airway surgery and can lead a healthy, comfortable life.