Effect of Different Volumes of SPSIP Block in Breast Surgery

This randomized, double-blind study will compare the effectiveness of three different volumes of serratus posterior superior intercostal plane block for postoperative pain control in patients undergoing unilateral breast surgery with axillary lymph node dissection. Ninety participants will be randomly assigned to receive 20 mL, 30 mL, or 40 mL of 0.25% bupivacaine. The primary outcome is total tramadol consumption during the first 24 hours after surgery. Pain scores, time to first analgesic request, rescue analgesic use, quality of recovery, postoperative nausea and vomiting, block success, and block-related complications will also be evaluated.