Femoral and sciatic nerve blockades and incision site infiltration in rabbits undergoing stifle joint arthrotomy.

This study was designed to determine whether perineural injections of local anaesthetics decreases intraoperative nociception and improves postoperative analgesia in New Zealand White rabbits undergoing experimental stifle arthrotomy. All animals were anaesthetized using isoflurane and received morphine intramuscularly. The sciatic and femoral nerves of the leg to be operated on were located using a nerve stimulator (1 Hz, 0.5 mA). Rabbits were assigned to a treatment group (LB; n = 12) or a placebo group (P; n = 12) in a randomized blinded fashion. Group LB received lidocaine 2% (1 mg/kg) combined with bupivacaine 0.5% (0.25 mg/kg) injections around the sciatic and femoral nerves (0.1 mL/kg total volume per site) and subcutaneous infiltration of the incision site with lidocaine 1% (1.25 mg/kg). Group P received the same volume of 0.9% NaCl. Rabbits in group P required higher doses of intraoperative fentanyl and propofol to reduce heart rate and suppress increase in systolic blood pressure, and maintain an adequate anaesthetic plane. Interventional analgesia (buprenorphine and carprofen) was required significantly earlier in rabbits in group P (2 and 6 h after the first nerve blockade, respectively) based on assessment of their pain-related behaviour and range of motion. Using a visual analogue scale (0 mm= no pain to 100 mm= maximal possible pain), rabbits in group LB were judged to show significantly less pain compared with rabbits in group P (14 ± 10 mm and 37 ± 25 mm, respectively) 2 h after nerve blockade. In conclusion, this technique of perineural analgesia combined with incision site infiltration reduced intraoperative fentanyl requirements and improved postoperative analgesia in rabbits.

Comparison of caudal and pre-scrotal castration for management of perineal hernia in dogs between 2004 and 2014.

AIMS: To compare peri- and post-operative complications associated with caudal scrotal castration (CSC) and perineal hernia repair with pre-scrotal castration (PSC) in conjunction with another surgical procedure. METHODS: Medical records were reviewed for 51 intact male dogs that were admitted to the Veterinary Emergency and Surgical Center, Levittown, PA, and underwent a CSC and perineal hernia repair using an internal obturator muscle flap (IOMF) between 2004 and 2014. Perioperative, and major and minor post-operative complications noted within the 2 week follow up period were reported and compared to 91 intact male dogs that underwent a PSC in conjunction with a second surgical procedure. RESULTS: There were no recorded perioperative or major post-operative complications in either group. There were 3/51 (6%) minor post-operative complications in the CSC group compared to 6/91 (7%) in the PSC group. There were 2/51 (4%) and 4/91 (4%) cases that developed heat, erythema and swelling associated with the incision site and 1/51 (2%) and 2/91 (2%) cases that developed scrotal swelling in the CSC and PSC groups, respectively. Overall, there was no difference in the prevalence of minor complications between the two groups (p=0.86). CONCLUSIONS AND CLINICAL RELEVANCE: Caudal scrotal castration was not associated with more perioperative or postoperative complications relative to PSC. Utilising the CSC approach eliminates the need to aseptically prepare and drape a second site when carrying out perineal hernia repair, as well as the need for patient repositioning. Thus, we recommend that CSC be the preferred surgical technique when performing orchiectomy in dogs concurrent with perineal hernia repair.