Comparison of External Oblique Intercostal Plane Block and Subcostal Transversus Abdominis Plane Block for Postoperative Analgesia After Open Radical Gastrectomy: A Single-Blind Randomized Trial.

Background: Ultrasound-guided fascial plane blocks are increasingly incorporated into multimodal analgesia for upper abdominal surgery. Although both the external oblique intercostal plane (EOIP) block and the subcostal transversus abdominis plane (scTAP) block have been used for postoperative analgesia, evidence directly comparing their efficacy after open radical gastrectomy is lacking. We compared the postoperative analgesic efficacy of bilateral EOIP and bilateral scTAP blocks in patients undergoing open radical gastrectomy. Methods: In this prospective, single-center, randomized, patient-blinded trial, 60 adults undergoing elective open radical gastrectomy were randomly assigned to receive either a bilateral ultrasound-guided EOIP block or a bilateral scTAP block. The primary outcome was cumulative morphine consumption during the first 24 postoperative hours. Secondary outcomes included postoperative Numeric Rating Scale (NRS) scores, rescue analgesic requirements, postoperative nausea and vomiting (PONV), and length of hospital stay. Results: Thirty patients were analyzed in each group. 24 h cumulative morphine consumption did not differ significantly between the EOIP and scTAP groups (24.3 ± 11.4 mg vs. 22.4 ± 8.8 mg, respectively; mean difference 1.9 mg, 95% confidence interval -3.10 to 6.97; p = 0.47). Morphine consumption at 2, 6, and 12 h also showed no statistically significant differences. Postoperative NRS scores showed no significant differences at any time point. Rescue analgesic requirements and the proportion of patients experiencing PONV episodes did not differ significantly between the groups. No complications were observed. Conclusions: Among patients undergoing open radical gastrectomy, no statistically significant differences were detected between bilateral EOIP and bilateral scTAP blocks in postoperative opioid consumption, pain scores, rescue analgesic requirements, or PONV. These findings do not establish equivalence or efficacy relative to standard care without a block and warrant confirmation in larger multicenter trials.