Epidural and quadratus lumborum blocks with 1% lidocaine provide comparable analgesia while maintaining cardiovascular and respiratory stability in dogs undergoing ovariohysterectomy

Abstract

Objective: To compare the analgesic efficacy and cardiovascular and respiratory effects of lumbosacral epidural (EP) and ultrasound-guided lateral quadratus lumborum (QL) block with 1% lidocaine in dogs undergoing elective ovariohysterectomy (OVH).Methods: Following an experimental, prospective study design, dogs presented for OVH at the Veterinary Teaching Hospital of the Universidad Nacional del Centro de la Provincia de Buenos Aires during 2024 to 2025 were randomly assigned to receive either an EP injection of 1% lidocaine (0.4 mL/kg) or a bilateral QL block with the same formulation and dose per site (n = 12 each group). All dogs were premedicated with dexmedetomidine and meloxicam, anesthetized with propofol, and maintained with sevoflurane under spontaneous ventilation. Intraoperative analgesic requirements, physiological variables, and postoperative pain scores were evaluated for 6 hours after extubation.Results: 24 healthy, female mixed-breed dogs (mean age, 1.65 years [SD, 0.8 years]; mean weight, 17.45 kg [SD, 6 kg]) were included in the study. A total of 23 dogs completed the study; 1 QL case was excluded due to block failure. No evidence of differences was observed between groups in heart rate, blood pressure, or respiratory parameters. The number of fentanyl boluses did not differ between groups. Postoperative pain scores were similarly low in both groups, with no need for rescue analgesia.Conclusions: EP and QL blocks with 1% lidocaine provided comparable anesthetic stability and postoperative analgesia in dogs premedicated with dexmedetomidine and meloxicam undergoing OVH.