Effect of intravenous lidocaine infusion on long-term postoperative pain after spinal fusion surgery

Background:Intravenous lidocaine infusion is known to reduce postoperative pain for days or weeks beyond the infusion time, and plasma half-life in several types of surgical procedures.Objectives:To evaluate the effect of intravenous (IV) lidocaine infusion on long term postoperative pain intensity for 3 months in patients undergoing spinal fusion surgery.Study Design:Prospective randomized, double-blinded study.Setting:Assiut University Hospital, Assiut, Egypt.Methods:Forty patients undergoing spinal fusion surgery were randomized into 2 equal groups (n=20 in each). Patients in the lidocaine group received IV lidocaine at a dosage of 2.0mg/kg slowly before induction of anesthesia, followed by lidocaine IV infusion at a rate of 3.0mg/kg/h until the end of surgery. Patients in the control group received an equal volume of normal saline. The following data were assessed: pain by Visual Analog Score (VAS) at 1 hour, 6 hours, 12 hours, 24 hours, 48 hours, at discharge time, and at 1 month, 2 months, and 3 months post-operation, time to first request for additional analgesia, and total morphine consumption in 24 hours.Results:Lidocaine significantly reduced the postoperative pain score (VAS) for up to 3 months (P<.05), and significantly reduced morphine consumption (4.5mg vs. 19.85mg) in the 1st 24 hours postoperative. Lidocaine also significantly, prolonged (P<.05) the time to first request for additional analgesia (9.562.06 hours vs 1.82 +/- 0.91 hours).Conclusion:Intra-operative lidocaine, when given intravenously as a bolus followed by an infusion, significantly decreased long term postoperative back pain intensity in patients undergoing spinal fusion surgery.