External oblique intercostal plane block versus subcostal transversus abdominis plane block for pain control in supraumbilical surgeries: a randomised controlled clinical trial

Background: The external oblique intercostal block (EOIB) was designed to provide upper median and lateral abdominal wall analgesia. Its efficacy was mainly explored in case reports and retrospective studies. Our study aimed to prospectively assess EOIB efficacy in open supraumbilical procedures compared to subcostal transversus abdominis plane (TAP) blockade for pain control in the first 24 postoperative hours. Methods: A total of 63 adult patients scheduled for variable upper abdominal procedures involving supraumbilical incision were allocated randomly to three groups (21 each). After induction of general anaesthesia, patients received either EOIB (group E), subcostal TAP block (group T), or no block (group C). The primary study outcome was morphine consumption in the first 24 postoperative hours. Secondary outcomes included intraoperative fentanyl supplements, haemodynamic variables, time to first rescue analgesia, postoperative Visual Analogue Scale (VAS) scores, the occurrence of complications, and patient satisfaction. Results: The 24-hour postoperative morphine consumption and time to first rescue analgesia were significantly lower and longer, respectively, in the EOIB and subcostal TAP groups compared to the control group (p < 0.001) without significant differences between the intervention groups. VAS scores at rest and during cough were significantly higher in the control group than in the intervention groups. However, EOIB achieved less intraoperative fentanyl requirements than subcostal TAP (p = 0.04), with better haemodynamic stability and longer control of pain than the control group. Conclusion: The EOIB is as effective as subcostal TAP in delivering optimal analgesia and reducing perioperative opioid requirements. Considering the intraoperative advantages of EOIB in terms of lower fentanyl needs and better haemodynamic control, the EOIB is an attractive substitute for postoperative pain reduction following open upper abdominal surgeries