Safety and efficacy of the external oblique intercostal plane block for postoperative analgesia in upper abdominal surgery: A systematic review and meta-analysis

ABSTRACT The external oblique intercostal block (EOIB) is a novel regional anesthesia technique for upper abdominal surgery. However, its efficacy and safety compared to other analgesic strategies remain uncertain. This study aimed to evaluate the impact of EOIB on postoperative analgesia and recovery in adults undergoing upper abdominal surgery. PubMed, Web of Science, and the Cochrane Library were searched from inception until August 2025 for randomized controlled trials comparing EOIB to placebo, no block, or other regional techniques. Primary outcomes were 24-h postoperative opioid consumption and pain scores (rest/movement). Secondary outcomes included rescue analgesia requirement, opioid-related adverse effects, block-related complications, and recovery parameters. EOIB significantly reduced postoperative opioid consumption when compared with control at 24 h (SMD − 0.45; P < 0.001) and 48 h (SMD − 1.38, 95% confidence intervals [CI] −2.60 to − 0.16; P = 0.03). At rest, postoperative pain scores at 2, 4, 6, 12 and 24 h were all significantly lower (all P ≤ 0.03). Likewise, the reductions in pain during movement were only observed at 6, 12, and 24 h (all P ≤ 0.03). EOIB prolonged the duration until first rescue analgesia was initiated with a mean difference of 1.62 h ( P < 0.001) and reduced the incidence of postoperative nausea and vomiting (OR 0.21, 95% CI 0.07–0.068). No significant differences were observed in overall rescue analgesia use. Overall, EOlB effectively reduces postoperative opioid consumption in upper abdominal surgery, particularly within the first 12 h with a favorable safety profile.