Study reveals BOAS bone abnormality link

A newly published study has indicated bone abnormalities could limit the effectiveness of surgery on dogs affected by brachycephalic obstructive airway syndrome (BOAS).

Researchers at the University of Cambridge’s vet school say their findings highlight the importance of pterygoid bone malformations when advising owners of clinical prognoses.

The BSAVA PetSavers-funded paper, published in the Journal of Small Animal Practice, is based on assessments of 144 brachycephalic dogs referred to the school’s Queens Veterinary Hospital between 2015 and 2021, plus 30 control dogs.

BOAS severity was determined through the use of a percentage-based index and the Respiratory Functional Grading System developed by the university and The Kennel Club.

Pterygoid medialisation

Across the brachycephalic cases overall, 17% experienced a good surgical outcome compared to 19% for whom results were considered poor.

But, among French bulldogs, a “significantly greater pterygoid medialisation index” was reported in cases of poor surgical outcomes than those which were successful.

The index, which quantified the extent of medialisation, was determined through a ratio of the width of the basisphenoid bone and the interpterygoid distance.

The paper said there were “currently no effective surgical options” to address pterygoid deformities in BOAS-affected dogs” and their assessment could help deliver “better-informed predictions” of surgical effectiveness.

Breeding programmes

It also suggested the index should be included in breeding programmes to help improve future generations’ welfare.

Lead author Sze Lynn Yuen added: “BOAS is a complex disease which encompasses breed-specific anatomical lesions.

“The medialisation index will be useful for vets in practice to guide them on the likely prognosis prior to surgery.

“It would be beneficial to identify the significance of the medialisation index on a larger dataset of BOAS-affected patients as the next step.”