Bilateral Erector Spinae Plane Block Versus Bilateral Oblique Subcostal Transversus Abdominis Plane Block for Postoperative Analgesia in Colorectal Surgery

Inclusion Criteria: * Age 18 to 75 years old. * Both sexes. * American Society of Anesthesiologists (ASA) physical status II-III. * Scheduled for open colorectal surgery under general anesthesia. Exclusion Criteria: * History of opioid abuse. * Chronic opioid consumption. * Body mass index (BMI) ≥ 35 kg/m2. * Severe cardiac insufficiency, defined as New York Heart Association (NYHA) class III or IV heart failure. * Renal failure, defined as an estimated glomerular filtration rate (eGFR) \< 30 mL/min/1.73 m². * Hepatic encephalopathy. * Having a skin infection at or near the puncture site. * Coagulopathy, defined as platelet count \< 100,000/mm³, INR \> 1.5, or use of anticoagulant therapy that could not be withheld. * Allergy to drugs used in the study. * History of previous or recurrent laparoscopic cholecystectomy procedures.