Efficacy of retrolaminar and paravertebral block for postoperative analgesia in percutaneous nephrolithotomy patients - A double-blinded randomized controlled trial

This double blinded randomized controlled trial aims to compare the postoperative analgesic efficacy of ultrasound guided retrolaminar block and paravertebral block in patients undergoing percutaneous nephrolithotomy under spinal anesthesia. After detailed preanesthetic evaluation, patients will be randomized into two groups: Group A - receiving RLB at the T10 level and Group B- receieving PVB at the T10 level , each with 20ml of 0.25% bupivacaine following saline confirmation of needle placement . All patients will receive standard anesthesia. Postoperatively, pain will be asssessed using the Visual Analog scala (VAS) at regular intervals over 24 hours by an independent blinded observer. The primary outcome is the duration of postoperative analgesia, defined as the time to first rescue anlagesia, while secondary  outcomes include pain scores, total rescue analgesia consumption, and block related complications.