Postoperative Analgesia in Patients Undergoing Open Upper Abdominal Surgeries: External Oblique Intercostal Plane Block vs. Quadratus Lumborum Block

Open upper abdominal surgeries with subcostal incisions are a cause of severe pain and can lead to pulmonary and cardiac complications, detrimental physiological effects, and may also have psychological, economic, and social adverse effects if inadequately treated. Effective pain control can avoid these complications and contribute to several clinically valuable outcomes, including earlier patient mobilization and quicker recovery, which can result in a shortened hospital stay and reduced costs. Opioids are the gold standard in postoperative pain control. however, it increases the incidence of opioid related adverse events such as respiratory depression, dizziness, nausea, vomiting and constipation. Regional analgesia plays an important role in perioperative multimodal analgesic regimens for major abdominal surgeries. The ultrasound-guided technique provides several options for relieving postoperative pain. The aim of this study is to compare the efficacy and safety of ultrasound guided external oblique intercostal plane block versus quadratus lumborum in patients undergoing open upper abdominal surgeries.

Inclusion Criteria: * Patients from both sexes. * 18 to 60 years old. * ASA physical status I- III scheduled for elective open upper abdominal surgeries, as (open nephrectomy, open cholecystectomy, liver resection, ….). * Patients with BMI (18.5-35) kg/ m2. Exclusion Criteria: * Patients uncooperative or refuse to sign the consent of regional block. * Patients with known coagulation defects. International normalized ratio (INR)\> 1.5), and thrombocytopenia if platelet count \< 100.000). * Patients with known hypersensitivity to bupivacaine, or any of the used drugs. * Patients with hepatic impairment, as Child-Pugh class B or C, AST/ALT \> 3 times the upper limit of normal, or total bilirubin \> 2 mg/dL. * Patients with renal impairment, chronic kidney disease stage 4 or 5 (eGFR \< 30 mL/min/1.73 m²), or on regular dialysis. * Patients with pre-existing myopathy, defined as a clinically diagnosed muscular disorder characterized by muscle weakness, elevated creatine kinase levels, or a history of inherited or acquired muscle disease (e.g., polymyositis, muscular dystrophy). * Patients with pre-existing neuropathy, if clinically diagnosed as peripheral or central nerve dysfunction, including chronic sensorimotor deficits or conditions such as diabetic neuropathy, radiculopathy, or multiple sclerosis. * Patients with chronic pain syndromes, defined as pain persisting for more than 3 months, including fibromyalgia, complex regional pain syndrome (CRPS), or chronic pain requiring long-term opioid or neuropathic pain medications. * Patients with sepsis at the site of injection. * Patients with history of long-acting opioids or steroids preoperatively