Opioid-sparing effect of postoperative continuous intravenous nefopam in multilevel degenerative lumbar spinal fusion: a randomized double-blind placebo-controlled trial

Study Design: Prospective, randomized, double-blind, placebo-controlled trial. Purpose: This study aimed to evaluate the analgesic efficacy and safety of postoperative continuous intravenous nefopam infusion in reducing opioid consumption after multilevel degenerative lumbar spinal fusion. Overview of Literature: Nefopam is a nonopioid, nonsteroidal analgesic with multimodal mechanisms, comprising serotonin, norepinephrine, and dopamine reuptake inhibition, as well as glutamatergic pathway modulation. Despite its opioid-sparing properties demonstrated in other surgeries, evidence supporting its role in spinal surgery, particularly multilevel fusion, remains limited. This study aimed to investigate the efficacy and safety of intravenous nefopam in reducing opioid consumption after multilevel lumbar spine fusion. Methods: This study randomized 66 patients undergoing decompressive laminectomy and fusion for degenerative lumbar spinal stenosis involving three or more levels to receive either nefopam or a placebo immediately postoperatively. All patients received standardized multimodal analgesia, including intravenous morphine patient-controlled analgesia, acetaminophen, and nonsteroidal anti-inflammatory drugs. The primary outcome includes total morphine consumption at 24 hours. Secondary outcomes include cumulative morphine consumption at 12, 36, and 48 hours, pain scores at rest and during movement, and adverse event incidences. Results: Morphine consumption was significantly lower at 24 hours in the nefopam group compared with placebo (10.44±8.40 mg vs. 20.49±16.60 mg, p =0.013). Reductions persisted at 36 hours (13.44±9.99 mg vs. 28.42±22.54 mg, p=0.009). Pain scores at rest and during movement were similar between groups at all time points (p>0.05). Adverse event rates, including nausea/vomiting (12.1% vs. 9.1%) and tachycardia (12.1% vs. 6.1%), did not significantly differ. No serious complications occurred. Conclusions: In patients undergoing multilevel degenerative lumbar spinal fusion, continuous intravenous nefopam infusion significantly reduced postoperative opioid requirements without worsening adverse events. Nefopam may be a useful opioid-sparing adjunct in multimodal postoperative pain protocols for major spine surgery.