Analgesic Efficacy of External Oblique Intercostal Block vs Subcostal Transversus Abdominis Plane Block in Open Surgical Nephrectomy

Patients will receive transversus abdominis plane block with an oblique subcostal approach in the supine position. The anesthesiologist will place the linear ultrasound transducer obliquely on the upper abdominal wall along the subcostal margin near the xiphisternum of the sternum in the midline of the abdomen. The anesthesiologist will direct a 22G, 80 mm needle toward the transversus abdominis fascia and inject 25 mL of 0.25% bupivacaine between the rectus abdominis and transversus abdominis muscles along the subcostal line.

Patients will receive external oblique intercostal block the patient will be in the supine position with their ipsilateral arm abducted, A linear ultrasound transducer will be placed in the sagittal plane between the midclavicular and anterior axillary lines at the level of sixth rib, with the orientation marker directed cranially. The skin will be sterilized, and the probe will be placed over the sixth rib medial to the anterior axillary line in a parasagittal orientation the in-plane technique with a 22G, 80 mm block needle will be used to inject 25 ml of 0.25% bupivacaine into the external oblique intercostal plane.

Patients will receive IV morphine 0.1mg/kg after induction of general anesthesia. General anesthesia induction will be performed with fentanyl 1-2 μg/kg, propofol 2-3 mg/kg, and rocuronium 0.6 mg/kg and maintained with sevoflurane.