# Comparing the Use of Transverse Abdominis Plane Block and Splash Block for Postoperative Pain Control in Dogs Undergoing Mastectomy—A Blinded Randomized Prospective Clinical Study

## TL;DR

This study compares two pain control methods in dogs after mastectomy surgery, finding that the TAP block provides better pain relief and reduces the need for additional pain medication.

## Contribution

The study provides empirical evidence comparing the efficacy of Splash block and TAP block for postoperative pain management in canine mastectomy.

## Key findings

- Dogs receiving TAP block had lower postoperative pain scores 3–12 hours after surgery.
- TAP block was associated with significantly less need for rescue analgesia compared to the Splash block.

## Abstract

Mastectomy for tumour removal is a major surgery which involves a high level of pain in the postoperative phase. As such, postoperative pain reduction with appropriate analgesia is key to animal welfare and positive surgical outcomes. The aim of this study was to evaluate the potential differences in pain control following mastectomy between the Splash block, which consists of topical application of local anaesthetic (LA) directly to surgical site prior to the closure of upper tissue layers, and the Transverse Abdominis Plane (TAP) block, which entails injecting LA into the fascial plane situated between the internal abdominal oblique and transversus abdominis muscles. TAP block exerted in a longer-lasting effect, and was associated with a reduced need for rescue analgesia with opioids and ketamine.

To compare the use of postoperative analgesia for mastectomy, 44 dogs were randomly allocated to either the Splash treatment group (group A) or the Transverse Abdominis Plane block treatment group (TAP, group B). Following intramuscular (IM) premedication with pethidine (4 mg kg−1) and acepromazine (0.01 mg kg−1), anesthesia was induced with intravenous (IV) propofol and maintained with isoflurane by an anesthetist (DC) who was unaware of the treatment. In group A, ropivacaine 0.5% (2 mg kg−1) was administered prior to surgical wound closure. In group B, ropivacaine 0.5% (0.8–1 mg kg−1 per point) was administered by ultrasound-guided TAP block with two injection points per treated body side. At the end of the surgery, all dogs received pethidine (4 mg kg−1 IM), meloxicam (0.2 mg kg−1 IV), and acepromazine (0.005 mg kg−1 IV). The animals’ pain was assessed by the anesthetist, who remained unaware of the treatment type used, via the Short Form of the Glasgow Composite Pain Scale. When the pain scores were ≥6, methadone (0.2 mg kg−1 IV) and gabapentin (10 mg kg−1 per oral) were started. When the pain score remained ≥ 6, ketamine (1 mg kg−1 subcutaneously) was administered. The dogs in the TAP block group had lower postoperative pain scores 3–12 h after anesthesia administration was terminated and required significantly less rescue analgesia.