When assessing candidates for brachycephalic obstructive airway syndrome (BOAS) surgery, you may hear client concerns about long-term success. Thanks to a new study in Veterinary Surgery—described as the first in which clinicians objectively assess the long-term (>6 months after surgery) respiratory outcomes after BOAS surgery—there may be some evidence to guide your response to these clients.
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This longitudinal cohort study compares the preoperative, short-term postoperative, and long-term postoperative respiratory outcomes of 32 client-owned dogs with BOAS. With this comparison, researchers hoped to provide veterinarians and clients with an evidence-based long-term prognosis with consideration to the maintenance of postoperative improvements in respiratory function.
The surgical procedures performed in this study to alleviate components of multilevel BOAS—defined as 2 or more of the following: stenotic nares, elongated or thickened soft palate, everted tonsils, laryngeal collapse—were not standardized yet rather tailored to each dog’s anatomy. The median long-term postoperative assessment was 1645 days after surgery. Respiratory functional grade (RFG) and BOAS indices were compared to preoperative values.
Jane Ladlow, MA, VetMB, Cert SAS, Cert VR, Dipl.ECVS, MRCVS, is a director at Granta Veterinary Specialists and Director of Clinical Research at the University of Cambridge. She discussed the study and some key takeaways in this Q&A.
Q: In this study, the surgical improvements observed in the short-term were maintained without evidence of functional decline—suggesting that “the physiological benefits of BOAS surgery are durable [and] short-term postoperative improvements [serve] as a reliable indicator of longer-term outcomes.” Would you say that is the primary takeaway of this study?
Yes, definitely. Over the years, there have been constant comments about dogs deteriorating after surgery. This study indicates that if body condition score remains constant, airway function does not significantly change. That gives the clinician and owner a better idea of the long-term prognosis and more confidence in the procedures.
Q: Along those same lines, the short-term and long-term postoperative BOAS indices did not differ. Has that conclusion changed your clinical recommendations?
Not really. We were told that BOAS is a progressive disease, and there is a peak in presentation in the first few years of life. Many dogs, however, are stable unless they are Grade 3 (severely affected). That is reflected in the respiratory functional grades (RFG) data, which is in progress. I recommend surgery if dogs have clinical signs that impact their quality of life—stertorous breathing that affects exercise tolerance—Grade 2. Currently, I’m reassessing data from dogs that were Grade 2 at 12 months and 12 years of age. I rarely recommend surgery for dogs with Grade 1—stertor only audible with a stethoscope—which I consider subclinical disease.
Q: The owner questionnaire revealed that 94% (29/31) of owners thought surgery improved their dog’s quality of life. Furthermore, 55% (17/31) of owners felt that their dog no longer had breathing issues after surgery; and 97% of owners (30/31) said they would recommend surgery to other owners of dogs with BOAS. Considering one of your areas of clinical research is effective surgical strategies for BOAS, are those statistics higher or in line with what you typically see in practice?
I think they are in line with our expectations. You see the occasional dog with very difficult lesion sites, for example, a French bulldog with a very narrowed interpterygoid region or a pug with a huge macroglossia; those are tricky. Most dogs, however, greatly improve following surgery.
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Q: Only 1/16 dogs exhibited worse long-term postoperative BOAS indices than preoperative assessments. Beyond that markedly small cohort, what are the most common issues you see related to BOAS surgery?
In the short term, regurgitation, due to surgery and anesthesia, is the biggest problem we see. Once that resolves, most dogs seem relatively stable. If we use laser turbinectomy or radiofrequency coblation to address the nasal turbinates, those dogs often have reverse sneezing that can last 3 to 4 weeks. I suspect that the nasal cavity must be irritated during that time, leading to sneezing.
Q: Do you have any ongoing or future studies that evaluate other aspects of BOAS?
We have just published a paper on the internal conformational risk factors seen in the bulldog, French bulldog, and pug. The lesion sites are different for the 3 breeds, reflecting their varying lineages. Interestingly, 60% of BOAS variability in the bulldog can be explained by the size of the trachea. This indicates that the thickened/elongated palate seen in the bulldog is more of a secondary change. Most bulldogs still respond very well to surgery; in fact, this breed often has the best measurable response. (The RFG Scheme works well for the bulldog, and this study used whole-body plethysmography and the RFG Scheme to grade the dogs.)
The other study that is ongoing and about to be published focuses on the prevalence and severity of BOAS in 14 other brachycephalic breeds. Many breeds have airway obstruction, and we wanted to highlight the risk factors for various breeds and help breeders move away from unhealthy conformations. (We’ve already published a paper on the Boston Terrier, which aimed to make the risk factors as clear as possible.)
Q: Is there anything you would like our readers to know that has not been mentioned?
With regard to the research mentioned above on other brachycephalic breeds, we looked at nostril status. In pretty much all the breeds we’ve looked at, the degree of nostril stenosis is the strongest conformational risk factor for BOAS. If breeders were to work on one area, that is where I would direct them.
We also looked at nostril mobility versus nostril grade in a paper published last year. Severely and moderately stenotic nostrils were less likely to be mobile compared to mildly stenotic or open nostrils. Thus, stenotic nostrils are a double whammy—less space and minimal functionality as an airway opening.
Read the full story
Comparison of short- and long-term objective respiratory outcomes after surgery for brachycephalic obstructive airway syndrome.
Johnson DA, Liu NC, Ladlow JF. Vet Surg. Published online October 18, 2025. doi:10.1111/vsu.70034