BOAS anatomy
There are several components that can make up BOAS and lead to difficulty breathing, some of the most common include:
- Stenotic nares: nasal openings that are too small in size.
- Elongated soft palate: Similar to humans, the soft palate in dogs is located on the roof of the mouth just behind the hard palate. In many brachycephalic breeds, the soft palate is too long and hangs down in front of the opening of the windpipe creating restricted airflow.
- Hypoplastic trachea: a windpipe that is too narrow.
- Laryngeal collapse: weakening of the cartilage at the top of the windpipe. There are different stages of laryngeal collapse, and the degree of collapse can worsen with time.
- Other related issues can include aberrant nasal turbinates (nasal scroll bones that grow in abnormal locations), hiatal hernia (intermittent sliding of the stomach into the thoracic cavity), and regurgitation (bringing up food and water).
Surgical options and risks
Some of the components listed above can be surgically addressed to try to improve breathing, and to try to prevent progression of laryngeal collapse. The most common procedures include shortening of the soft palate (this surgery is called a staphylectomy) and widening of the nasal openings (nares wedge resection). Though surgical procedures can never make the breathing completely normal due to their brachycephalic anatomy, it can lead to a drastic improvement in their breathing and long-term function.
Any type of surgery or anesthesia in these brachycephalic breeds can lead to swelling of the airway and problems with breathing around the time of anesthesia. For this reason, we take these procedures very seriously and your veterinarian may recommend pre-anesthetic medications to reduce the risk of regurgitation and help keep your pet calm the day of surgery. In some cases, your veterinarian may advise that anesthesia and surgery be performed at a 24-hour specialty center where overnight hospitalization is available.