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

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

Gathering insights on experiences with RBA techniques.

Cross-sectional survey.

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.

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).

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

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