Effects of infiltration of the incision site with bupivacaine on postoperative pain and incisional healing in dogs undergoing ovariohysterectomy.

Objective: To determine the effects of infiltration of the incision site with bupivacaine hydrochloride as part of a multimodal analgesia protocol (incisional block) on postoperative analgesia and incisional healing.

Design: Randomized controlled clinical trial.

Animals: 92 shelter-owned female dogs undergoing routine ovariohysterectomy.

Procedures: As part of a multimodal analgesic protocol for ovariohysterectomy, dogs received 1 of the following treatments at the incision site: no injection (26 dogs), preincisional infiltration with saline (0.9% NaCl) solution (12 dogs) or bupivacaine (21 dogs), or postincisional infiltration with bupivacaine (33 dogs). Postoperative pain was assessed with the Glasgow pain scale and response to mechanical stimulation with von Frey filaments. Incisions were monitored for signs of inflammation (edema, erythema, and discharge) and complications in wound healing.

Results: There was no difference in pain scores or response to mechanical stimulation over time among treatments. There were no significant differences in incisional edema or discharge among treatments. There was significantly more erythema in dogs that received preincisional infiltration with saline solution at 4 hours after surgery and less erythema in dogs that received postincisional infiltration with bupivacaine at 24 hours after surgery, compared with other treatments. The number of complications for dogs that had preincisional infiltration of bupivacaine was higher than for dogs that had other treatments; complications included excessive inflammation, splenic laceration, and herniation.

Conclusions And Clinical Relevance: No additional analgesic benefit was found in dogs that underwent local bupivacaine infiltration as part of a multimodal analgesic protocol for ovariohysterectomy.