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

Simple Summary The GIN-TONIC block is an interfascial ultrasound-guided regional anesthesia technique that desensitizes the lumbosacral plexus and provides analgesia to the pelvic limb. Different methods have been attempted previously, such as blocking specific plexuses (e.g., lumbar and sacral plexuses) and nerves (e.g., femoral and sciatic). However, these approaches either resulted in excessive motor block or failed to encompass all the required areas for surgery. This study assessed the efficacy of the GIN-TONIC block in dogs premedicated with either acepromazine or dexmedetomidine for surgeries on the hip and stifles. It also checked how well the dogs could move after the surgery. The results showed that the GIN-TONIC block provided adequate perioperative analgesia, independently of the drug used in premedication. During recovery, dogs showed minimal motor block, suggesting that GIN-TONIC block provides a motor-protective analgesic effect. However, more research is needed to fully understand how effective the GIN-TONIC block is during surgery.Abstract 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 mu g kg-1 intravenously (IV)] as premedication, and GD received dexmedetomidine (2 mu g 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 mu g 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.