Background: Posterior vertebral decompression and stabilization surgery addresses spinal instability and other conditions but can cause significant pain if not managed well. This can lead to hemodynamic disturbances and chronic pain. Opioids are common for pain management but have side effects like drowsiness and nausea. Low-dose intravenous lidocaine during surgery can reduce opioid use and postoperative pain. This study aims to assess its effect on serum substance P levels, neutrophil-lymphocyte ratio, and pain intensity. Methods: This study used a double-blind randomized clinical trial conducted from April to June 2024. Patient who underwent decompression and posterior vertebral stabilization surgery were selected via consecutive sampling. Participants were split into two groups: the intervention group received intravenous lidocaine, while the control group received a placebo. Data were analyzed using SPSS 25, with results presented as narratives, tables, or graphs. Statistical tests included t-tests and Mann-Whitney U tests, with significance set at p < 0.05. Results: A total of 30 patients were included in this study with 15 patients in each groups. At 6h, 12h, and 24h postoperatively, pain intensity was significantly lower in the lidocaine group compared to the control group (p<0.05). Additionally, the neutrophil-lymphocyte ratio (NLR) decreased significantly in the lidocaine group at 6h postoperatively compared to the control group. However, no significant difference in substance P levels was found between the two groups. Conclusion: Lidocaine can lower postoperative NRS scores, decrease postoperative NLR values, and reduce the difference in substance P levels between postoperative and preoperative measurements.