Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 0 0 2026 01 11 1374 1374 Azim Honarmand Department of Anesthesiology and Critical Care, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. Mehdi Mahmoodkhani Department of Neurosurgery, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. Behzad Nazemroaya Department of Anesthesiology and Critical Care, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. Alireza Ahmadian Department of Anesthesiology and Critical Care,School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. 2025 08 10 2025 09 13 Background: This randomized controlled trial evaluated the analgesic effect of adding subcutaneous ketamine to bupivacaine in lumbar fusion surgery. Methods: 46 adult patients were randomized to receive subcutaneous bupivacaine with or without ketamine before incision. Pain scores (VAS), time to first rescue analgesia, opioid use, extubation time, and patient satisfaction were assessed. Results: The ketamine group had higher early postoperative pain (30 and 60 min; P < 0.05) but showed prolonged time to rescue analgesia (P = 0.037) and reduced opioid use (not statistically significant). Extubation time was significantly longer. Satisfaction scores were similar. Conclusion: Subcutaneous ketamine delayed opioid use but increased early pain and extubation time. It may be considered in selected patients, pending further research. https://aacc.tums.ac.ir/index.php/aacc/article/view/1374