Comparison of the Effects of Subcostal Transversus Abdominis Plane Block Versus Rectus Sheath Block on Postoperative Pain in Midline Abdominal Incision Laparotomy

For this group, S-TAP blocks will be performed bilaterally right after the surgery completion with the patients in supine position. For S-TAP, a high frequency linear transducer USG is placed below the xiphoid process, on the linea alba transversely. The probe will then be moved laterally along the costal margin with a slight oblique motion to match the costal arc until the transversus abdominis muscle is visualized under the rectus abdominis muscle. The block needle will be inserted in-plane from inferolateral to superomedial direction, aiming toward the fascial plane between transversus abdominis and rectus abdominis muscles. After negative aspiration and hidrodissection with 1-2 mL of saline and verifying the location of the needle tip, 20 mL of 0.25% bupivacaine will be administered on each side, with a total of 40 mL bilaterally.

For this group, RS blocks will be performed bilaterally right after the surgery completion with the patients in supine position. For RSB, a high frequency linear transducer USG is placed above the umbilicus transversely. The probe will then be moved laterally until the rectus abdominis muscle, its posterior sheath and the peritoneum can be visualized clearly. The block needle will be inserted in-plane from lateral to medial direction, aiming toward the posterior sheath of the rectus abdominis muscle. After negative aspiration and hidrodissection with 1-2 mL of saline and verifying the location of the needle tip, 20 mL of 0.25% bupivacaine will be administered on each side, with a total of 40 mL bilaterally.