External oblique intercostal plane block: A scoping review of anatomy, techniques, and clinical applications

The external oblique intercostal plane block (EOIPB) is a novel, ultrasound guided regional anaesthesia technique targeting the fascial plane between the external oblique and external intercostal muscle. This scoping review aimed to comprehensively map current evidence on EOIPB, covering its anatomical basis, techniques, clinical applications, efficacy, and safety. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines, a systematic search of PubMed, Scopus, and Cochrane databases was conducted for articles published between January 2019 and July 2025. Eligible studies encompassed clinical trials, observational studies, case series, case reports, cadaveric investigations, and relevant clinical correspondences involving EOIPB for surgical or chronic pain related indications. Forty-two studies involving 1610 patients were included, with EOIPB performed in 765 cases. The block was most commonly administered at the sixth rib between the midclavicular and anterior axillary lines using an in-plane sagittal approach, providing consistent T6-T10 dermatomal coverage. EOIPB demonstrated opioid-sparing effects, lower pain scores, and improved recovery across various surgical settings. It was found to be comparable or superior to other regional techniques, such as the transversus abdominis plane block, erector spinae plane block, and wound infiltration. Catheter-based EOIPB facilitated prolonged analgesia and proved useful within enhanced recovery after surgery protocols. Reported complication rates were low. Overall, EOIPB is a promising regional anaesthesia technique, offering safe, effective, and versatile analgesia for upper abdominal and lower thoracic surgeries. Further high-quality comparative studies and standardisation of techniques are warranted to establish its definitive role in perioperative care.