Intravenous Lidocaine Infusion in Lumbar Fusion Surgery

Elective lumbar fusion surgery is associated with moderate to severe postoperative pain and often requires substantial perioperative opioid administration. Excessive opioid use may lead to adverse effects such as nausea, vomiting, sedation, respiratory depression, and delayed mobilization. Intravenous lidocaine infusion has been proposed as part of multimodal analgesia because of its analgesic, antihyperalgesic, and anti-inflammatory properties. This randomized, placebo-controlled clinical trial aims to evaluate the effect of intraoperative intravenous lidocaine infusion on postoperative opioid consumption and early recovery outcomes in patients undergoing elective lumbar fusion surgery. Patients will be randomly assigned to receive either intravenous lidocaine infusion or placebo during surgery. The primary outcome is cumulative postoperative opioid consumption within the first 24 hours after surgery. Secondary outcomes include intraoperative opioid consumption, postoperative pain scores, time to first rescue analgesic, quality of recovery, postoperative nausea and vomiting, time to mobilization, and length of hospital stay. In addition, inflammatory and oxidative stress biomarkers including interleukin-6 (IL-6) and markers of thiol-disulfide homeostasis will be measured preoperatively and postoperatively.