Revised-Paravertebral Nerve Block
ProcedureParticipants assigned to the intervention group will receive an ultrasound-guided revised paravertebral block (r-PVB) after induction of general anesthesia and before surgical incision. With the patient in the supine position and the ipsilateral arm abducted, a high-frequency linear ultrasound probe is placed at the mid-axillary line to identify the ninth to eleventh intercostal space on the operative side, together with the pleura and intercostal muscle layers. Using an in-plane technique, the block needle is advanced under real-time ultrasound guidance into the plane of the internal intercostal muscle. Correct needle tip placement is confirmed by small test injections producing characteristic pleural displacement on ultrasound. After confirmation, 30 mL of 0.5% ropivacaine is injected into the target plane to achieve a functional paravertebral block. Routine surgery then proceeds.