External Oblique Intercostal Block Versus Erector Spinae Plane Block on Postoperative Pain in Laparoscopic Radical Gastrectomy

With the patient in the supine position, a high-frequency linear array probe (6-15 MHz) is used to perform a sagittal parasagittal oblique scan at the level of the 6th rib, between the right anterior axillary line and midclavicular line. The external oblique muscle, intercostal muscles, and ribs are identified. Using an in-plane technique, a 21G, 100mm block needle is inserted from a superomedial to inferolateral direction, with the needle tip positioned in the plane between the external oblique muscle and the intercostal muscles at the caudal edge of the 6th rib. 30ml of 0.375% ropivacaine is injected on each side, for a bilateral administration.

With the patient in the lateral decubitus position (surgical side up), a low-frequency convex array probe (2-5 MHz) is used to perform a sagittal scan approximately 2-3 cm lateral to the spinous process of T8 or T9. The transverse process and the erector spinae muscle are identified. Using an out-of-plane technique, a 21G, 100mm block needle is advanced until contact is made with the transverse process. The needle is then withdrawn 1-2 mm to position its tip within the fascial plane deep to the erector spinae muscle and superficial to the transverse process. 30 ml of 0.375% ropivacaine is injected on each side, for a bilateral administration.