One of the biggest changes we have encountered here at Aurora in the last few years is the explosion in popularity of brachycephalic breeds such as English Bulldogs, French Bulldogs and Boston Terriers. In the early days of our clinic a visit from one of our Bulldog patients would have been a bit of a novelty but ownership of these breeds has seen a sharp rise in recent years with a lot of our clinical time now dedicated to discussing and treating the various health issues that affect these breeds. Undoubtedly a lot of these individuals make great, healthy pets - new members of the family that are full of fun and mischief. However, there are increasing numbers of these dogs that suffer from well established medical issues such as respiratory, spinal, orthopaedic, skin and gastrointestinal issues. Covering all these conditions in one blog would make for a very long read, so this current entry will cover respiratory disease and I will go into more detail on the others in a future blog.
The term brachycephalic relates to the shape of a dogs skull, usually used to describe dog breeds that have developed ‘short noses’ or ‘flat faces’. This anatomical difference in the skull leads to major changes in the development of an individual’s airway, with changes often starting at the nostrils but potentially affecting the entire airway, even extending deep into the lungs. Essentially all brachycephalic breeds will have these airway changes to some degree; however the severity to which it affects an individual day to day is very much down to the extent of the abnormalities. Many dogs with mild changes will lead perfectly normal and active lives and will never require treatment. However, some individuals with more advanced changes will require regular veterinary care and potentially surgery to help them cope. We refer to these patients as suffering from ‘Brachycephalic Obstructive Airway Syndrome’- as this is a bit of a mouthful we will often refer to a patient as suffering from BOAS.
Our patients that are suffering from BOAS will often be booked in to come and see us for breathing difficulties but sometimes it can present as more subtle signs such as lethargy or vomiting. Often these patients are the individuals that don’t cope well on hot days, are noisy breathers or bad snorers. Some patients find it hard to settle, often trying to sleep in unusual positions. The internet is full of pictures of French Bulldogs sleeping in what is assumed to be funny positions, but often this is a sign of chronic sleep deprivation as the dog is struggling to get into a position where it is confident to sleep. BOAS is considered as a progressive condition with individuals suffering from chronic disease potentially developing laryngeal collapse (failure of the structure at the back of your throat through which air passes into your windpipe). However, all BOAS patients are at risk of acute swelling of the upper airways, which can happen any time the dog overheats or is physiologically stressed and without emergency medical management can be potentially fatal.
The anatomical changes that contribute to these issues are well documented. The easiest one for owners to identify at home is narrow nostrils, referred to as stenotic nares. This limits the amount of air entering the airways whenever the dog breaths. However, many of the anatomical changes are out of sight, deeper in the dogs airways. The soft palate (the spongy part of the roof of your mouth, right at this back) plays an important role in both breathing and swallowing. Many of these patients will have a soft palate which is far too long, protruding into the opening of the larynx. This further limits the amount of air which can make it through into the lungs. As mentioned these are the two most commonly diagnosed and treated anatomical components of BOAS. However, there are several other factors that can potentially play a role such as narrowing of nasal cavity bones, underdevelopment of the lower airways and herniation of the stomach through the diaphragm. These areas are more complex to assess or potentially treat, so the majority of surgical treatment is focused on the issues that can be routinely accessed such as the nose and throat.
Many cases of BOAS can be managed conservatively without the requirement for surgery. This usually means being consistently aware of the risks associated with overheating, for example, avoiding exercise during the hotter parts of the day throughout the summer months and utilising cooling aids such as cooling jackets and mats. This approach may work well for individuals that are at the lower end of the BOAS spectrum. For those individuals that are more severely affected, surgery is often necessary. Surgical intervention will not cure an individual but rather it aims to lessen a patient’s clinical signs, allowing them to live more comfortably and reducing the chance of acute emergency airway swelling as mentioned earlier.
Surgical techniques vary but usually involve a combination of nares and soft palate surgery. Surgery on stenotic nares aims to broaden the nasal aperture by removing a wedge of tissue from both sides of the nose, the surgical incision is then sutured closed - pulling the edges of the incision together and as a result widening the nostril. Recovery from this procedure is usually relatively straight forward and most brachycephalic patients with stenotic nares would benefit from this type of procedure. We occasionally perform nares resection at the same time as other procedures such as routine neutering.
Soft palate surgery is aimed at reducing the amount of soft tissue at the back of the throat, allowing more air to pass through the larynx and into the lower airways. Traditional surgical techniques involve cutting and removing the end of the soft palate, with newer techniques designed to remove tissue from further forward in the palate and advancing the palate forward in the mouth. Although soft palate surgery is sometimes necessary and potentially life changing for many of these patients, before committing to surgery owners should always be aware of the potential risks and complications associated with palate surgery and the post-operative recovery period. Although the surgery itself is often relatively straight forward there is a much higher risk of complications than we would usually accept for other types of surgery. Complications range from acute issues during the anaesthetic process to serious postoperative concerns. One of the biggest risks is a condition called aspiration pneumonia. This occurs because surgery alters the anatomy at the back of the throat and can therefore influence the dog’s ability to swallow properly. This increases the chance of food and water entering the trachea rather than the oesophagus when the dog feeds. This can happen at any time after the dog has had surgery and can be potentially fatal.
At our practice we feel the decision to undertake surgery should always be an informed and well thought out process. Some of our patients with severe BOAS will undeniably benefit from surgery however some dogs that are affected to a lesser extent may live comfortable lives without being exposed to the risks of surgical intervention. The increasing popularity of brachycephalic breeds in the last few years has led the veterinary profession to develop a wider understanding of the requirements of these patients and therefore easier access to BOAS surgery. Although we would support any brachycephalic owner in their decision to go for surgery we would hope that the decision is made in full knowledge of the potential benefits and complications. It is widely accepted that there is a requirement for long-term efforts towards responsible breeding of brachycephic individuals lesser affected by respiratory disease rather that the normalisation of BOAS surgery to provide a healthier future for these breeds.