Intraoperative Methadone Improves Postoperative Pain Control in Patients Undergoing Complex Spine Surgery

Abstract

Patients undergoing complex spine surgery frequently experience severe pain in the postoperative period. The combined opiate receptor agonist/N-methyl-d-aspartate receptor antagonist methadone may be an optimal drug for these patients given the probable involvement of N-methyl-d-aspartate systems in the mechanism of opioid tolerance and hyperalgesia. Twenty-nine patients undergoing multilevel thoracolumbar spine surgery with instrumentation and fusion were enrolled in this prospective study and randomized to receive either methadone (0.2 mg/kg) before surgical incision or a continuous sufentanil infusion of 0.25 μg/kg/h after a load of 0.75 μg/kg. Postoperative analgesia was provided using IV opioids by patient-controlled analgesia. Patients were assessed with respect to pain scores (visual analog scale from 0 to 10), cumulative opioid requirement, and side effects at 24, 48, and 72 hours after surgery. Demographic data, duration, and type of surgery were comparable between the groups. Methadone reduced postoperative opioid requirement by approximately 50% at 48 hours (sufentanil versus methadone group, median [25%/75% interquartile range]: 63 mg [27.3/86.1] vs 25 mg [16.5/31.5] morphine equivalents, P = 0.023; and 72 hours: 34 mg [19.9/91.5] vs 15 mg [8.8/27.8] morphine equivalents, P = 0.024) after surgery. In addition, pain scores were lower by approximately 50% in the methadone group at 48 hours after surgery (sufentanil versus methadone group [mean ± SD] 4.8 ± 2.4 vs 2.8 ± 2.0, P = 0.026). The incidence of side effects was comparable in both groups. Perioperative treatment with a single bolus of methadone improves postoperative pain control for patients undergoing complex spine surgery.