Efficacy of Preoperative Oral Clonidine in Spine Surgery: A Systematic Review and Meta-Analysis of Randomized...

Introduction: This study presents the first systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating the efficacy and safety of oral clonidine in spinal surgery to guide clinical practice and inform future research. Methods: RCTs were identified through four databases (PubMed, Scopus, Web of Science, Cochrane Central) up to August 2025. Risk of bias was assessed, and intraoperative and postoperative outcomes were extracted. Data were pooled using mean differences (MD) or risk ratios (RR) with 95% confidence intervals. Results: Eight RCTs with 474 patients (237 clonidine, 237 control) were included. Four studies had a low risk of bias, while two had some concerns, and two had a high risk. Clonidine had no impact on surgery duration but significantly reduced blood loss (MD = -177.76 mL), mean arterial pressure (MD = -11.33 mmHg), and heart rate (MD = -21.18 bpm). Regarding postoperative outcomes, clonidine was associated with improved analgesia, including lower pain scores up to 12 h and a longer time to first analgesic request, with no significant difference in pain scores at 24 h or total postoperative opioid consumption. No significant increase in postoperative complications, including bradycardia, dizziness, headache, or visual disturbances, was observed. Surgeon satisfaction was higher in the clonidine group. Despite high heterogeneity in some outcomes, sensitivity analyses confirmed the robustness of most findings. Conclusions: Prophylactic oral clonidine in spinal surgery significantly reduces blood loss, heart rate, and mean arterial pressure, with added analgesic benefits and good tolerability. Further high-quality RCTs are needed to confirm these results in broader patient populations.