Laparoscopically guided transversus abdominis plane block versus local wound infiltration analgesia in laparoscopic surgery for peritoneal endometriosis: A prospective randomized controlled double-blinded LTAP-trial.

INTRODUCTION: Endometriosis patients often suffer from more severe pain in association with surgical procedures. The aim of this study was to investigate whether laparoscopically guided transversus abdominis plane block (LTAP) offers an opioid-sparing effect compared to local wound infiltration (LWI) analgesia in laparoscopic surgery performed for suspected peritoneal endometriosis. MATERIAL AND METHODS: In this single-center prospective, randomized, controlled, double-blinded clinical study, 46 patients were randomized to receive either levobupivacaine inserted in the four quadrants of the abdomen at LTAP points and saline at trocar sites (n = 23) or saline at the LTAP points and levobupivacaine at trocar sites (n = 23). The study size was based on a power calculation. The primary outcome, opioid consumption 24 h postoperatively, was measured using patient-controlled analgesia pumps. Secondary outcomes included postoperative pain scores and other enhanced recovery after surgery (ERAS) measures, as well as patient outcome questionnaires at six months after surgery. Statistical analyses were performed on an intention-to-treat basis. The study was prospectively registered in Clinicaltrials.gov, ID: NCT04735770, Jan 19, 2021; https://clinicaltrials.gov/study/NCT04735770?term=LTAP&rank=2. RESULTS: There was no significant difference in the mean opioid consumption (iv morphine equivalents) between the study groups: 31.8 ± 25.5 mg in the LTAP group and 27.5 ± 19.3 mg in the LWI group (mean difference 4.3 mg, 95% CI -9.2 to 17.7, p = 0.52). No significant differences were found in the postoperative pains scores, mean operation times, mean total blood loss, or mobilization between the study groups. 17 (73.9%) patients in each group received histological diagnosis of peritoneal endometriosis of the samples obtained during surgery. Times to discharge were 24.4 ± 4.3 (LTAP) and 28.1 ± 14.8 h (LWI), p = 0.25. No complications related to LTAP or LWI were reported. CONCLUSIONS: In this study performed on women suffering from long-term abdominal pain preoperatively, no significant differences were found between LTAP and LWI as regards to postoperative opioid consumption, postoperative pain, ERAS factors, or safety.