Study finds palatine approach falls short for canine maxillary block: full analysis

A newly published cadaveric study suggests veterinary clinicians shouldn't swap out the standard infraorbital technique for a palatine approach when performing canine maxillary nerve blocks. The study, published March 15, 2026, in the Journal of Small Animal Practice, found the palatine approach had substantially worse performance, including an 80% procedural failure rate compared with 20% for the infraorbital technique. (deepdyve.com)

The idea behind the new technique was straightforward: the major palatine nerve is a branch of the maxillary nerve, and the major palatine foramen sits closer to the main maxillary trunk than the infraorbital foramen. In theory, that could allow a more direct, lower-volume, or more complete block. The Cambridge team set out to test that hypothesis by comparing the two approaches in donated canine cadaver heads, using both CT to assess contrast spread and dissection to measure how much of the nerve was actually stained. (api.repository.cam.ac.uk)

What they found went the other way. The stained portion of the maxillary nerve was shorter with the palatine technique, with a median of 0 mm versus 35 mm for the infraorbital approach. Procedural failure, defined as staining less than 6 mm of nerve, occurred in 8 of 10 palatine injections and 2 of 10 infraorbital injections. The study also found the palatine approach more often contaminated the soft palate submucosal area, and investigators reported subjective resistance to injection in many of those cases. The authors said those results likely reflect the harder-to-access anatomy of the palatine foramen compared with the more palpable infraorbital landmark. (api.repository.cam.ac.uk)

That matters because maxillary nerve blocks are used well beyond dentistry. The paper notes their role in oral and maxillofacial surgery, rhinoscopy, nasal biopsy, and brachycephalic airway procedures. Existing literature cited by the authors supports the infraorbital approach as the most studied canine technique, while other alternatives, such as transorbital, maxillary tuberosity, and now ultrasound-guided in-plane approaches, are being explored to improve accuracy or reduce complications. A 2026 Veterinary Anaesthesia and Analgesia paper, for example, reported moderate cadaveric success but encouraging clinical sensory blockade with an ultrasound-guided maxillary block in dogs, underscoring that innovation in this space is continuing, even if this particular palatine route fell short. (api.repository.cam.ac.uk)

There doesn't appear to be broad external commentary on this specific paper yet, but the study fits with a wider theme in regional anesthesia: anatomical plausibility alone isn't enough. Broader veterinary and comparative anesthesia literature emphasizes that block success depends on reliably placing anesthetic near the target nerve, and that the infraorbital/maxillary region already has multiple described approaches with different tradeoffs in ease, safety, and consistency. In that context, this study offers useful evidence against adopting a new blind landmark technique before validation. (api.repository.cam.ac.uk)

Why it matters: For veterinary professionals, especially those in dentistry, surgery, anesthesia, and referral practice, this is the kind of negative data that's immediately useful. It argues against adding a technically less accessible palatine approach to routine protocols for canine maxillary blocks, at least as a blind alternative to infraorbital placement. It also reinforces the need for training, anatomical familiarity, and technique selection based on evidence, not just novelty. For pet parents, that translates into a simple point: newer isn't always better, and the best-supported methods still matter when teams are trying to provide reliable perioperative analgesia. (api.repository.cam.ac.uk)

What to watch: The next step is likely not clinical rollout of the palatine approach, but more work on modified or image-guided maxillary block techniques, including ultrasound-guided methods and CT-informed anatomical targeting, to see whether reliability can be improved without adding risk. (api.repository.cam.ac.uk)