Brachycephalic Obstructive Airway Syndrome (BOAS)

French Bulldog sitting in the back of a car

One of the most common breeds of dogs in today’s world is the French bulldog, which is also the poster child for brachycephalic dogs. Brachycephalic dogs typically are bred to have a short nose and flat face as compared to dolichocephalic dogs, who have a normal-length nose. Common brachycephalic dog breeds include French bulldogs, Pugs, Boston Terriers, and Shih Tzus. Due to this confirmation, these breeds are naturally prone to a condition called brachycephalic obstructive airway syndrome (BOAS), which affects different areas of the respiratory tract, most commonly as a varying combination of an elongated/thickened soft palate, everted laryngeal saccules, stenotic nares, hypoplastic trachea, and an increase mucosal contact points or aberrant turbinate bones within their nasal cavity. All these abnormalities can contribute to an obstructive breathing pattern that ultimately can cause increased upper airway noise (stertor), sleep apnea, exercise intolerance, difficulty tolerating warmer weather, and potentially collapse from an inability to breathe. There are a variety of surgical treatment options available for this syndrome aimed to help improve overall airflow and the ability to breathe better. These surgical treatment options include surgical options to shorten or thin the soft palate (partial staphylectomy vs folded flap palatoplasty), removal of the pharyngeal tonsils to decrease tissue in the back of the mouth (tonsillectomy), removal of everted laryngeal tissues (sacculectomy) and resection of the obstructive portion of the nasal wing to help reduce airway resistance.

The most important aspects of these surgical procedures mainly focus on shortening the soft palate and widening of the nares. Due to the shorter nasal length, the tissue in the mouth can be overly abundant, leading to a longer-than-normal soft palate. This elongated soft palate can then protrude into the airway and create an airway obstruction. Due to this abnormal amount of tissue within the airway, dogs can create a stertorous (noisy) breathing pattern, and patients can potentially even obstruct the excess tissue. The main surgical treatment utilized to correct this issue is through shortening of the soft palate called a partial staphylectomy. This procedure can be performed using various instruments, including laser, ligasure, and surgical scissors. Another technique called a folded flap palatoplasty has been introduced in recent years. It not only shortens the soft palate but also thins out the palate by removing some of the fat within the tissue itself. Both soft palate procedures have demonstrated good success in opening the entrance to the airway and improving airflow. Since the nasal passage creates the most resistance to normal airflow, widening the nares is another important aspect of surgery for brachycephalic breeds. Stenotic nares, or narrowed nostrils, can lead to a very small nasal opening, making it more difficult for these patients to breathe normally. Therefore, widening the nares is an important aspect of surgery for brachycephalic breeds. There are numerous techniques described for both widening the nostrils, including the trader’s technique, horizontal and vertical wedge resection, alapexy, and a variety of other well-described techniques. More recently, a newer technique called an Ala-vestibuloplasty has been described where the surgeon will resect both the outer and inner obstructive portion of the nasal wing to help improve airflow for patients. This technique results in a larger increase in the airway and, overall, less resistance. This technique has been used in both brachycephalic dogs (and cats!) with good success, and new research continues to be published.

Most patients will have a combination of the above surgical treatments performed based on their confirmation. Which treatments are indicated will be determined following a sedated oral examination that is done prior to the surgical procedure. Most patients recover smoothly, but it is essential to keep them hospitalized post-operatively to closely monitor them for any trouble breathing or vomiting/regurgitation. Very rarely, complications secondary to swelling of the soft tissues can lead to a complete obstruction of the airway, necessitating emergency treatments, such as a nasotracheal tube or temporary tracheostomy. It is important to understand that these procedures will not cure patients of their brachycephalic airway syndrome; instead, the goal of these procedures is to improve clinical signs and quality of life and decrease the risk of respiratory distress associated with this syndrome.

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