Global survey on the utilisation and experiences with different retrobulbar anaesthesia techniques in horses.

Abstract

Background: Retrobulbar anaesthesia (RBA) is relevant for ocular surgery in standing sedated horses.

Objectives: Gathering insights on experiences with RBA techniques.

Study design: Cross-sectional survey.

Methods: An online survey collected information on the respondents' professional background, indications, injection methods, use of ultrasound assistance, medication, and complications associated with RBA in horses.

Results: Two-hundred and thirty-eight veterinarians from 25 countries contributed. 86.1% were members of veterinary specialty colleges. RBA indications were enucleation (97.8%), corneal surgery (29.5%), eyelid surgery, paracentesis of the vitreous and anterior chamber, cataract surgery and vitrectomy (<10.0% each). The dorsal approach was most commonly used (88.8%), followed by the 4-point (34.8%), lateral (8.9%), and modified Peterson blocks (2.2%). Ultrasound-assisted needle positioning was used by 16.1%. Most commonly administered drugs were mepivacaine (67.4%), lidocaine (56.3%), and bupivacaine (37.9%). Complications included lack of anaesthesia (40.6%), exophthalmos (33.5%), chemosis (32.1%), and retrobulbar haemorrhage (22.8%). The choice of injection method and reported complications were significantly influenced by participants' professional backgrounds: as horse caseload percentage increased, dorsal injection use decreased (p = 0.011, OR 0.981, 95% CI 0.967-0.996), injection-related complications increased (p < 0.001, OR 1.015, 95% CI 1.006-1.024), and postoperative complications decreased (p < 0.001, OR 0.983, 95% CI 0.976-0.991). As ophthalmic case percentage increased, dorsal injection use increased (p = 0.009, OR 1.022, 95% CI 1.006-1.039), 4-point injection method decreased (p = 0.044, OR 0.993, 95% CI: 0.986-1.000), injection-related complications decreased (p < 0.001, OR 0.985, 95% CI 0.978-0.993), and postoperative complications increased (p < 0.001, OR 1.019, 95% CI 1.012-1.027).

Main limitations: Results may reflect selection and recall bias; complication prevalence was not assessed.

Conclusions: Dorsal and 4-point blocks are the most used, varying by participants' professional background. RBA causes mostly mild complications; severe ones are rare.