Timing of Subcostal TAPB Combined With Rectus Sheath Block for Postoperative Pain After Laparoscopic Cholecystectomy

Inclusion Criteria: * Elective laparoscopic cholecystectomy * Adults aged 18 to 80 years * Ability to understand the study procedures and provide informed consent * American Society of Anesthesiologists (ASA) physical status I-III Exclusion Criteria: * Presence of significant pain unrelated to the target disease that may interfere with pain assessment * Known allergy or contraindication to study medications (ropivacaine, acetaminophen, nefopam, or pethidine) * Planned single-port laparoscopic cholecystectomy * American Society of Anesthesiologists (ASA) physical status IV or higher * Infection of the abdominal wall or skin at the injection site, or anatomical abnormalities of the abdominal wall * Major neurological, psychiatric, or systemic diseases that may affect pain perception, treatment response, or study evaluation * Requirement for postoperative mechanical ventilation * Pregnancy or breastfeeding * Considered unsuitable for the study by the investigator * Refusal to participate or inability to provide informed consent