Use of peri-incisional liposomal bupivacaine was not different than placebo regarding pain score or rescue analgesia in a randomized clinical trial of 83 dogs

Objective To evaluate the impact of peri-incisional liposomal bupivacaine (LB) on postoperative pain scores, opioid use after soft tissue surgeries, and incidence of incision site complications in dogs. Methods Client-owned dogs (n = 83) were enrolled in a randomized, blinded, placebo-controlled clinical study for dogs undergoing a variety of soft tissue surgical procedures between March 31, 2021, and August 18, 2022. After incision closure, an injection of a placebo (0.9% NaCl) or LB was administered into the peri-incisional subcutaneous tissues. Pain was assessed via the Glasgow Composite Measure Pain Scale (CMPS-SF) preoperatively, at extuba- tion, and at 2, 4, 8, 12, 24, 30, 36, 48, 54, 60, and 72 hours postoperatively or until time of discharge. The need for rescue analgesia was assessed based on CMPS-SF guidelines. The effect of LB on pain scores was analyzed with mixed-model linear regression, and the chi 2 test was used to examine effects on incision complications and need for rescue analgesia. Results 83 dogs were enrolled. There was no significant difference in CMPS-SF scores between LB and placebo groups at any time period. Rescue analgesia was administered to 21 dogs in each group and was not significantly different. There was no significant difference in incision site complications. The incidence of surgical site infections was 6.0% for all procedures. Conclusions Peri-incisional LB did not significantly decrease the use of rescue analgesia for postoperative soft tissue surgeries in a clinical setting with the use of multimodal analgesia. This is consistent with findings in human literature. Clinical Relevance Clinicians should not rely on LB used in the peri-incisional subcutaneous tissue to improve analgesia in patients undergoing soft tissue surgery.