Inclusion Criteria:  American Society of Anesthesiologists class II. Patients undergoing open nephrectomy for malignant renal tumors. Body mass index (BMI): > 20 kg/m2 and < 40 kg/m2.  Exclusion Criteria:  Patient refusal. Local infection at the puncture site. Coagulopathies with platelet count below 50,000 or an international normalized ratio >1.6. Renal and hepatic insufficiency. Unstable cardiovascular disease. History of psychiatric and cognitive disorders. Patients allergic to medication used. Abnormal anatomy of the thoracic region.