Ultrasound-Guided Greater Ischiatic Notch Plane Block Combined with the Caudal Quadratus Lumborum Block (GIN-TONIC Block) in Dogs Undergoing Pelvic Limb Surgery: Preliminary Results

: This study assessed the analgesic and motor effects of the GIN-TONIC block, a combination of the greater ischiatic notch plane block and the caudal lateral quadratus lumborum block, in 24 dogs undergoing pelvic limb surgery. Dogs were randomly divided into two equal groups: GA received acepromazine [(20 µg kg-1 intravenously (IV)] as premedication, and GD received dexmedetomidine (2 µg kg-1 IV). General anesthesia was maintained with isoflurane, and both groups received a GIN-TONIC block using 2% lidocaine. Nociception during surgery and postoperative pain [assessed using the Glasgow Composite Measure Pain Score (GCMPS-SF)] were assessed. Fentanyl (2 µg kg-1 IV) was administered if nociception was noted and morphine (0.5 mg kg-1 IV) was administered during recovery if the pain scores exceeded the predefined threshold. Motor function was assessed during the recovery period using descriptors previously reported. All dogs received analgesics at the 4 h mark before being discharged. Three and two dogs in GD and GA required fentanyl once. Postoperative pain scores remained ≤4/20 for all dogs except one. Dogs achieved non-ataxic ambulation within 38.9 ± 10.3 and 35.1 ± 11.1 min after extubation in GD and GA, respectively. This study highlighted the potential of the GIN-TONIC block as a feasible regional anesthesia method for delivering perioperative analgesia in dogs undergoing pelvic limb orthopedic surgery.