Intraoperative intravenous lidocaine for analgesia after oral cancer surgery with free perforator flap reconstruction: a randomised controlled trial

Intravenous lidocaine is effective in various surgical procedures, but its efficacy in oral cancer surgery is uncertain. We hypothesised that intraoperative intravenous lidocaine infusion can reduce 24-hour postoperative opioid consumption and reduce postoperative pain in patients undergoing oral cancer surgery with free perforator flap reconstruction. In this blinded, randomised, placebo-controlled trial, a total of 64 patients scheduled for elective oral cancer surgery with free perforator flap reconstruction were enrolled and randomly assigned to either the lidocaine group receiving intravenous lidocaine, or the control group receiving normal 0.9% saline. The primary outcome was the cumulative consumption of opioids at the first 24 h postoperatively. Secondary outcomes included the cumulative consumption of opioid drugs intraoperatively within 48 h and 72 h postoperatively, NRS scores at 24, 48, and 72 h postoperatively, lidocaine-related adverse events, incidence of chronic pain and neuropathic pain at 3 months postoperatively. From August 2024 to December 2024, a total of 102 patients were screened for eligibility, 64 patients were included. Baseline characteristics and surgery-related data were similar between the two groups. Median (IQR) 24-h morphine equivalent consumption was 43.38 (37.60, 47.45) mg in the lidocaine group vs. 35.15 (29.13, 47.60) mg in the control group (median difference, 5.31 mg; 95% CI, -3.45 to 11.95 mg; P = 0.295). There were no significant differences in pain scores at 24, 48, and 72 h, or in the incidence of chronic pain or neuropathic pain at 3 months follow-up ( P > 0.05). Among patients undergoing elective oral cancer surgery with free perforator flap reconstruction, intraoperative intravenous lidocaine infusion did not demonstrate a benefit in reducing 24 h postoperative opioid consumption (median difference, 5.31 mg; 95% CI, -3.45 to 11.95 mg; P = 0.295), acute pain (median difference, 0.00; 95% CI, -1.00 to 0.00; P = 0.762), or chronic pain at 3 months postoperatively (relative risk, 1.13; 95% CI, 0.50 to 2.55; P = 0.777). Trial registration : This trial was registered in the Chinese Clinical Trial Registry (ChiCTR2400088614) on August 22, 2024 ( https://www.chictr.org.cn/ ).