The Outcomes of an Opioid-Free Anaesthetic Plan in Fourteen Dogs Undergoing Enucleation Using an Ultrasound-Guided Supra-Temporal Retrobulbar Block: A Retrospective Case Series

SIMPLE SUMMARY: In recent years, loco-regional anesthesia has become a common practice in both human and veterinary medicine. In particular, it is widely used in the treatment of perioperative analgesia for neurological and orthopedic surgery. The advantage of successfully applying loco-regional anesthesia is better perioperative pain relief with a lesser need for systemic analgesic drugs. This case series aims to show how the practice of loco-regional anesthesia (retrobulbar block) has allowed good management of perioperative analgesia without the use of systemic opioids in 13 out of 14 dogs. A multimodal approach to perioperative analgesia focused on the use of a retrobulbar ultrasound-guided block with a supra-temporal approach was used in 14 dogs undergoing elective unilateral enucleation. A total of 2 out of 14 patients received rescue analgesia intraoperatively, while no patients required rescue analgesia during the postoperative period. No complications were recorded during the perioperative period, and all patients were discharged within the same day. ABSTRACT: The objective of this retrospective case series is to report the outcomes of an opioid-free anesthetic plan in dogs undergoing enucleation surgery. A total of 14 dogs were admitted for enucleation between March and December 2020. A multimodal approach to perioperative analgesia was used, with a focus on retrobulbar anesthesia. A combination of an ultrasound-guided retrobulbblock with a supratemporal approach in association with ketamine, dexmedetomidine and non-steroidal anti-inflammatory drugs was used in the reported cases. Intraoperative nociception was defined as an increase of 20% from the baseline in one or more of the following parameters: heart rate, respiratory rate or mean arterial pressure. An ultrasound-guided retrobulbar block in an opioid-free anesthesia regime was effective at managing the perioperative analgesia of 13 out of 14 dogs. In only one case, a bolus of fentanyl was administered to treat intraoperative nociception. Recovery was uneventful in all the dogs, and the postoperative pain scores remained below the intervention threshold at all time points. To the authors’ knowledge, this is the first reported case series of opioid-free anesthesia for enucleation in dogs.