For a number of years now we have been performing a bilateral maxillary nerve block for our BOAS cases at Anderson Moores Vet Specialists.
Of course this makes sense given the sensory innervation of the maxilla when considering the rhinoplasty. But we also found differences related to the palatoplasty. Sensory innervation of the soft palate in humans is by the maxillary branch of the trigeminal nerve, through the greater and lesser palatine nerves and the nasopalatine nerve, although sources relating to dogs cite the role of the glossopharyngeal nerve.
Our experience of this surgery is that when the surgeon incises the palate, dogs either react by an increase in heart rate or resp rate - and at worse, they swallow - which causes a challenge to the surgeon and stress to the anaesthetist!
A bilateral maxillary nerve block using the subzygomatic approach is part of our standard technique. The drug we use is bupivacaine 0.5% with a volume of 0.03ml/kg.
Our experiences are now supported by some new research published by colleagues formerly working at DWR.
The study was entitled 'Evaluation of bilateral maxillary nerve block in dogs undergoing surgery for brachycephalic obstructive airway syndrome' and you can read the full paper here.
In summary, this retrospective work demonstrated that bilateral maxillary nerve blocks reduced intraoperative fentanyl and injectable anesthetic requirement in dogs undergoing BOAS surgery. Hypotension, or bradycardia, were not different between groups.
Our view is that this publication aligns with our experience and supports our approach. We recommend this technique for improving analgesic management of BOAS cases.
References
De Gennaro C, Vettorato E, Corletto F. Evaluation of bilateral maxillary nerve block in dogs undergoing surgery for brachycephalic obstructive airway syndrome. Can Vet J. 2022 Jan;63(1):67-73. PMID: 34975170; PMCID: PMC8682927.
This post was co-written by Matt Gurney.
Matt sees referrals in the pain clinic at Anderson Moores Veterinary Specialists. You can also receive telemedicine advice from us here if you have a pain case where you need a helping hand.
Matt & Carl established Zero Pain Philosophy to provide educational resources & telemedicine to veterinary professionals enabling optimal management of pain.
Matt Gurney is an RCVS & European Specialist in Veterinary Anaesthesia & Analgesia and works at Anderson Moores Veterinary Specialists. Matt is Past President of the European College of Veterinary Anaesthesia & Analgesia.
Carl Bradbrook is an RCVS & European Specialist in Veterinary Anaesthesia & Analgesia and is Past President of the Association of Veterinary Anaesthetists. Carl works at Anderson Moores Veterinary Specialists.
The intended audience for this pain update is veterinary professionals. This pain update is based on clinical experience and independent opinion.