Comparison of the effect of Preoperative Pregabalin and Duloxetine on Postoperative Pain and Cognitive Function After Spinal Surgery

The adult patients scheduled for elective repair of lumbar disc herniation will randomly be divided into three groups. The randomization will be based on a computerized randomization table created by a researcher who will not involve in the study. The patients assigned in the first group will orally receive 75 mg pregabalin one hour before the operation. The dose (75 mg) will be repeated orally at the postoperative 12th and 24th hour, The patients in the second group will orally receive 60 mg duloxetine one hour before the operation. At the postoperative 12th hour, the patients in the second group will receive a matched-place capsule and at the 24th hour, they will orally receive 60 mg duloxetine again. The patients in the third group will orally receive matching placebo capsules at all time-points. One of the researchers who will be blind to the study groups and study drugs will directly observe the patients while receiving the capsules. At the end of the operation, 1 mg/kg intravenous tramadol will be applied to all of the patients for postoperative pain control. All of the patients will be assessed with Montreal Cognitive Assessment evaluations for cognitive function evaluation at the day before the operation and six hours after the operation. Postoperative pain evaluation will be done according to visual analog scale by a researcher who will be blinded to the study groups at the postoperative first minute, 30. minute, first hour, 12. hour, 24. and 48 hour.