Ultrasound Guided Rhomboid Intercostal Subserratus Plane Block Versus Erector Spinae Plane Block in Open Nephrectomy. Randomized Controlled Study

Under strict aseptic precautions, we will begin the scout scan with a high-frequency (6-12 MHz) linear US probe placed parasagitally in cephalocaudal orientation adjacent to C7 spinous process and the first rib will be identified with ultrasound. Then, we can directly count the ribs and come down to desired level of ribs or corresponding transverse process (the 8th thoracic spinous process). Once located, erector spinae and trapezius muscles will be identified overlying it. The skin will be infiltrated by 2 ml of lidocaine 1% subcutaneously and a 22- gauge, 80 mm needle (Stimuplex D, B-Braun, Germany) will be advanced in plane in the cranio-caudal direction. When the needle contacted the transverse process, 1 ml normal saline will be injected to confirm correct needle placement by visualizing the linear pattern of hydrodissection. After aspiration, 30 ml bupivacaine 0.25% will be injected.

While the patient in the sitting position, the 5th thoracic spinous process can be identified, a high-frequency (6-12 MHz) linear US probe will be placed in the sagittal plane medial to the medial border of the scapula and then rotated to be 1 to 2 cm medial to the medial scapular border. The plane between the rhomboid major and the intercostal muscles will be identified. 2 ml of lidocaine 1% subcutaneously and a 22- gauge, 80 mm needle (Stimuplex D, B-Braun, Germany) will be advanced in plane from a superomedial to an inferolateral direction then 15 ml of bupivacaine 0.25% will be administered (at the T5 level). Then the probe will be moved caudally and laterally to identify the tissue plane between the serratus anterior and the external intercostal muscle at the T8 level. The needle will be directed caudally and laterally beyond the inferior angle of the scapula. 15 ml of bupivacaine 0.25% will be administered.