Analgesic efficacy of external oblique intercostal plane block in adults undergoing abdominal surgery: systematic review and meta-analysis with trial sequence analysis

BACKGROUND: Analgesic efficacy of the novel external oblique intercostal plane block (EOIB) is inconclusive. Therefore, the aim of this systematic review and meta-analysis was to synthesize the evidence for analgesic efficacy of EOIB in adults undergoing abdominal surgery.METHODS: Electronic databases were searched until 31st May, 2025. Randomized controlled trials (RCTs) were considered provided they reported the difference in 24 h postoperative opioid consumption (primary objective). Secondary objectives were evaluation of static and dynamic pain scores, and other patient centric measures.RESULTS: Sixteen RCTs (972 patients) were included. EOIB significantly reduced 24 h postoperative opioid consumption (mean difference (MD): -7.67 mg; 95% CI: -12.12 to -3.21; P<0.001; I2=98%; prediction interval -26.96 to 11.53). Subgroup analysis revealed significant reduction in opioid consumption with EOIB vs. no blocks (MD: -9.86 mg; 95% CI: -13.44 to -6.28; P<0.001; I2=95%;). EOIB significantly decreased static and dynamic pain scores at all-time points and the need for rescue analgesia. The MD crossed the minimum clinically important difference (MCID) vs. no blocks only for static pain scores at 6 and 12 h and dynamic pain scores at 12 h. However, the 95% CI for MCID crossed the null line precluding definitive clinical effectiveness. No significant differences were found in other secondary outcomes. Required information size for benefit or futility for a difference in 24 h opioid consumption was 758 patients between EOIB and the subcostal transversus abdominis plane block group.CONCLUSIONS: EOIB provides superior analgesic efficacy vs. no blocks but the clinical effectiveness remains uncertain. Analgesic superiority over other blocks is inconclusive.