External oblique intercostal plane block for postoperative analgesia: A systematic review and meta-analysis of randomised controlled trials

Background and Aims: The external oblique intercostal plane (EOIP) block targets the lateral and anterior branches of T6-T10 intercostal nerves, providing upper abdominal wall analgesia. Its superficial location and ease in the supine position make it a promising option for multimodal analgesia. This systematic review and meta-analysis evaluated its efficacy versus other fascial plane blocks, wound infiltration, or no block in adults undergoing abdominal surgery. Methods: Following PRISMA guidelines (PROSPERO-CRD420251057391), databases were searched for randomised controlled trials (RCTs) comparing the EOIP block with other fascial plane blocks, wound infiltration, or no block. The primary outcome was 24-hour postoperative opioid consumption. The secondary outcomes were pain scores at rest and movement, intraoperative opioid use, time to first analgesic request, rescue analgesia needs, quality of recovery (QoR)-15 scores, and postoperative nausea and vomiting (PONV). Trial sequential analysis (TSA) was performed to assess the robustness of the primary outcome. Results: < 0.001); lowered pain scores at 6, 12, and 24 hours; decreased intraoperative fentanyl use; prolonged analgesia duration; reduced rescue analgesia needs; improved QoR-15 scores; and lowered PONV incidence. TSA confirmed conclusive evidence for EOIP versus no block but indicated further trials are needed versus fascial plane blocks. Conclusion: As compared to other fascial plane blocks, wound infiltration, or no block, the EOIP block provides opioid-sparing analgesia, sustained pain relief, and enhanced recovery in abdominal surgery. However, due to heterogeneity and a low-to-moderate certainty of evidence, further high-quality RCTs are warranted.