Comparison between External Oblique Intercostal Plane (EOI) Block and Incisional Local Infiltration Effect in Open Cholecystectomy: A Randomized Controlled Trial

Objective: To compare 24-hour postoperative opioid consumption, converted to intravenous morphine equivalents, between patients receiving external oblique intercostal plane (EOI) block and those receiving incisional local infiltration (LA) in open cholecystectomy. Primary outcome: 24-h morphine equivalents. Secondary: pain intensity on a 0–10 numeric rating scale (NRS). The minimal clinically important difference (MCID) was defined as ≥30% opioid reduction and ≥1-point NRS decrease.Material and Methods: Forty-four patients undergoing open cholecystectomy were randomized to EOI or LA (22 each). The EOI group received 20 mL of 0.25% bupivacaine for EOI block after skin closure, and the LA group received the same dose for local infiltration before skin closure. Results: For the primary outcome, 24-h morphine equivalent consumption showed no significant difference between the groups (–4.09 mg; p-value=0.058). Ward opioid use (2–24 h) was lower in the EOI group (10.2±5.3 mg) than the LA group (14.1±6.9 mg); mean difference –3.96 mg, 95% CI (–7.69 to –0.22), p-value=0.038. This 28% reduction did not meet the 30% MCID. Median movement NRS in the ward was significantly lower with EOI (6 [IQR 5–6]) than LA (7 [IQR 5.75–8]); median difference –1, 95% CI (–2.00 to 0.00), p-value=0.022, meeting the 1-point MCID.Conclusion: Although the EOI block did not significantly reduce total 24-hour morphine consumption, it was associated with a clinically meaningful reduction in movement-evoked pain.