Scheduled intravenous acetaminophen versus thoracic epidural analgesia for postoperative pain control after minimally invasive gastrectomy: multicentre randomized non-inferiority trial.

BACKGROUND

Thoracic epidural analgesia (TEA) is widely used for postoperative pain control in abdominal surgery, but its role in minimally invasive procedures remains unclear. This pragmatic multicentre open-label randomized non-inferiority trial evaluated whether scheduled intravenous acetaminophen combined with local wound infiltration provides non-inferior analgesia to TEA following minimally invasive gastrectomy.

METHODS

Adults with gastric adenocarcinoma categorized as clinical stage I-III (according to the Japanese classification of gastric carcinoma) who were undergoing laparoscopic or robot-assisted gastrectomy were randomized 1 : 1 to TEA or scheduled intravenous acetaminophen (1 g every 6 hours (h) for 72 h). All patients received wound infiltration with ropivacaine. Participants and clinicians were not blinded to the randomization; statisticians were masked. The primary endpoint in the study was the proportion of patients with a numerical rating scale (NRS) pain score ≥ 4 at rest 24 h after surgery, with a prespecified non-inferiority margin of 20 percentage points. Analyses used the modified intention-to-treat population.

RESULTS

Between June 2020 and May 2024, 140 patients were randomized and 135 were analysed (TEA 68, acetaminophen 67). At 24 h after surgery, 27.9% of patients in the TEA group and 23.9% in the acetaminophen group had an NRS score ≥ 4 at rest (risk difference -4.1%; 95% confidence interval -24.3 to 16.6), confirming non-inferiority. Pain trajectories, rescue analgesic use, patient satisfaction, and recovery were comparable between the two groups. No patient required rescue opioids, and there were no serious catheter- or acetaminophen-related adverse events.

CONCLUSION

Scheduled intravenous acetaminophen with wound infiltration was non-inferior to TEA for postoperative pain after minimally invasive gastrectomy and provided safe, effective, and opioid-sparing analgesia consistent with enhanced recovery principles. Registration number: UMIN000039505 (https://www.umin.ac.jp/english/).