Inclusion Criteria:  : This prospective randomized clinical study will include eighty patients with ASA I-II, aged 18-60 years scheduled for spine surgery  Exclusion Criteria:  : Excluded from the study are patients with known allergy to the study drugs, significant cardiac, respiratory, renal, CNS or hepatic disease, drug or alcohol abuse, pregnant women, patients refusing participation and psychiatric or mental illness that would interfere with perception and assessment of pain.