Efficacy of Adding Intrathecal Morphine to Erector Spinae Plane Block for Postoperative Analgesia After Midline Laparotomy

Inclusion Criteria Patients scheduled to undergo elective or emergency midline exploratory laparotomy. American Society of Anesthesiologists (ASA) physical status I, II, or III. Intact cognitive ability to comprehend study procedures, use the Numeric Rating Scale (NRS) accurately, and provide informed consent. Exclusion Criteria Contraindications to regional or neuraxial anesthesia (e.g., patient refusal, localized infection at needle insertion sites, known coagulopathy (INR \>1.5 or platelet count \<80,000/\\mu L), or un-pausable therapeutic anticoagulation). Known allergy or severe hypersensitivity to local anesthetics or morphine. Chronic pain conditions requiring daily opioid consumption for \>3 months preoperatively. Documented history of substance use disorder. Severe chronic respiratory disease (e.g., COPD requiring home oxygen therapy, or severe obstructive sleep apnea not managed with CPAP). Neurological or psychiatric conditions that compromise sensory perception or communication. Surgical incisions planned to extend significantly past the midline. Severe spinal deformities or a history of spinal surgery at the targeted block/injection interspaces. Concurrent enrollment in any other interventional clinical trial.