Implementation of magnesium sulphate as an adjunct to multimodal analgesic approach for perioperative pain control in lumbar laminectomy surgery: A randomized placebo-controlled clinical trial.

OBJECTIVE To investigate the effect of systemic intraoperative administration of magnesium sulphate when used in the context of a multimodal pain management plan on analgesics consumption and pain scores, and perioperative outcomes after lumbar laminectomy surgery. METHODS Seventy-four patients undergoing lumbar laminectomy were enrolled in this randomized, double-blind, placebo-controlled trial. Participants were randomly allocated to receive magnesium (20 mg/kg iv given as bolus before anesthesia induction followed by 20 mg/kg/h civ until surgery completion) or saline. Hemodynamic variables and desflurane consumption were noted at predefined time-intervals intraoperatively. Primary outcome was postoperative cumulative analgesic consumption over 24 h, while pain intensity (assessed by Visual Analogue Scale [VAS] at 1, 2, 4, 6 and 24 h), intraoperative hemodynamics and opioid requirements, recovery profile, time to first analgesic request, and adverse effects constituted secondary end-points. RESULTS Demographics, surgery duration, desflurane requirements, and recovery profile were comparable between groups. Magnesium attenuated hemodynamic response during incision and emergence from anesthesia. Postoperative analgesics consumption in morphine iv equivalents (mean difference -9.24 [95 %CI -13.31, -5.17] mg; p = 0.001) and VAS scores at all-time points of assessment were lower in magnesium group; this effect peaked at 4 h (mean difference -2.15 [95 %CI -3.21,-1.09; p = 0.001]. Magnesium reduced intraoperative remifentanil consumption and prolonged the time-interval to first rescue analgesia (p < 0.01). No notable adverse effects were recorded. CONCLUSION It occurs that magnesium infusion during lumbar laminectomy surgery potentiates perioperative analgesia and reduces analgesic requirements up to 24 h postoperatively. No profound adverse effect on either intraoperative hemodynamics or any other clinically relevant endpoints becomes evident.