Effect of Patient Position on Erector Spinae Plane Block in Thoracic Surgery

Adult patients scheduled for elective video-assisted thoracic surgery will be randomly assigned to receive ultrasound-guided unilateral erector spinae plane block either in the sitting position or in the lateral decubitus position. In both groups, the block will be performed at the same thoracic level using 30 mL of 0.25% bupivacaine under ultrasound guidance. Dermatomal sensory spread will be assessed 15 minutes after block placement using cold sensation (alcohol-soaked cotton) and pin-prick testing. Postoperative analgesia will be standardized in all patients using patient-controlled analgesia with tramadol. Pain scores and opioid consumption will be recorded during the first 24 postoperative hours. The primary outcome is the extent of dermatomal sensory spread. Secondary outcomes include postoperative pain scores, time to first rescue analgesic, and total opioid consumption within 24 hours.