Use of Intraoperative Ketamine and Methadone during Lumbar Spine Surgery: A Retrospective Study

Author(s): Roya Yumul, Ofelia Loani Elvir-Lazo, Paul F. White, Xiao Zhang, Waguih William IsHak, David Chernobylsky, Omar Durra, Hamed Sadeghipour.

Introduction: This retrospective chart review study was designed to assess the effect of administering intraoperative ketamine and methadone (vs. either drug alone) on postoperative pain and opioid consumption in patients undergoing elective spine surgery.

Methods: After IRB approval, we reviewed 268 patient charts, aged 18- 80 years undergoing elective lumbar spine surgery. They were assigned to one of three groups: (1) ketamine (n= 90), (2) methadone only (n= 90), (3) and ketamine + methadone (n=88). The data collected included demographic information, medical history, pre-procedure medications, pre-operative pain scores and morphine equivalents, intra/postoperativedata, pain scores, opioid consumption, and medication dosages at 24, 48, and 72 hours postoperatively.

Results: Patients receiving a combination of ketamine + methadone reported a higher postoperative pain score (p<0.0001), greater usage of opioid (p<0.0001) and adjuvants analgesics (p<0.05) at 24, 48, and 72 hours after undergoing spine surgery compared to patients receiving ketamine or methadone alone for intraoperative analgesia. However, patients in the ketamine + methadone combination group had a greater chronic usage of opioid analgesic medication prior to this operation.

Conclusion: In this retrospective chart review, the combined use of ketamine and methadone did not result in an advantage with respect to reducing postoperative pain scores or analgesic usage compared to ketamine or methadone alone in patients undergoing lumbar spine surgery. These negative findings were likely related to differences among the study populations with respect to chronic usage of opioid medications.