The Effect of Dexmedetomidine on Postoperative Opioid Consumption and Pain After Major Spine Surgery

BACKGROUND: Adult deformity correction spine surgery can be associated with significant perioperative pain because of inflammatory, muscular, neuropathic, and postsurgical pain. alpha-2 Agonists have intrinsic antinociceptive and antihyperalgesic properties that can potentially reduce both postoperative opioid consumption and pain. We hypothesized that intraoperative dexmedetomidine would reduce postoperative opioid consumption and improve pain scores in deformity correction spine surgery. METHODS: Patients undergoing >3 levels of thoracic and/or lumbar spine surgery were enrolled in this prospective randomized double-blind study to receive either dexmedetomidine (1 mu g/kg load followed by a continuous infusion of 0.5 mu g/kg/h) or saline. Both groups received a single dose of 0.2 mg/kg (ideal body weight) of methadone at the start of surgery. Intraoperative fentanyl was administered based on the clinical and hemodynamic signs suggestive of increased nociception. Postoperative analgesia was provided with a hydromorphone patient-controlled analgesia pump. Opioid consumption and pain scores were recorded at 24, 48, and 72 hours after surgery. RESULTS: One hundred forty-two participants were enrolled with 131 completing the study. There was no significant difference in demographics (age, sex, weight, and ASA physical status), percentage of participants with preoperative opioid use, and daily median opioid consumption between the groups. The study was terminated early after interim analysis. Intraoperative opioid use was reduced in the dexmedetomidine arm (placebo versus dexmedetomidine, median [25%-75% interquartile range]: 7 [3-15] vs 3.5 [0-11] mg morphine equivalents, P = 0.04) but not at 24 hours: 49 (30-78) vs 61 (34-77) mg morphine equivalents, P = 0.65, or 48 hours: 41 (28-68) vs 40 (23-64) mg morphine equivalents, P = 0.60, or 72 hours: 29 (15-59) vs 30 (14-46) mg morphine equivalents, P = 0.58. The Wilcoxon-Mann-Whitney odds are 1.11 with 97.06% confidence interval (0.71-1.76) for opioid consumption. No difference in pain score, as measured by the 11-point visual analog scale, was seen at 24 hours (placebo versus dexmedetomidine, median [25%-75% interquartile range]: 7 [5-7] vs 6 [4-7], P = 0.12) and 48 hours (5 [3-7] vs 5 [3-6], P = 0.65). There was an increased incidence of bradycardia (placebo: 37% vs dexmedetomidine: 59% P = 0.02) and phenylephrine use in the dexmedetomidine group (placebo: 59% versus dexmedetomidine: 78%, P = 0.03). CONCLUSIONS: Intraoperative dexmedetomidine does not reduce postoperative opioid consumption or improve pain scores after multilevel deformity correction spine surgery.