Dexmedetomidine Use and Intraoperative Bradycardia During Radiofrequency Rhizotomy for Trigeminal Neuralgia: A Retrospective Observational Study.

Purpose: Intraoperative bradycardia is a recognized complication during radiofrequency (RF) rhizotomy for trigeminal neuralgia, primarily related to the trigeminal-cardiac reflex. Dexmedetomidine is commonly used for its sedative and analgesic properties during these procedures; however, its hemodynamic impact has not been well characterized. This study aimed to evaluate the association between dexmedetomidine use and intraoperative bradycardia and to identify relevant clinical risk factors. Patients and Methods: This retrospective observational study included 517 patients who underwent RF rhizotomy for trigeminal neuralgia under monitored anesthesia care between August 2020 and December 2022. Patients were categorized into dexmedetomidine (Dex) and non-dexmedetomidine (Non-Dex) groups. The primary outcome was intraoperative bradycardia, defined as a heart rate <60 beats per minute or the need for atropine. Secondary outcomes included atropine use, intraoperative heart rate distribution, and anesthetic drug requirements. Multivariable logistic regression and age-stratified subgroup analyses were performed. Results: Dexmedetomidine was administered in 331 patients (64.0%). Intraoperative bradycardia occurred more frequently in the Dex group than in the Non-Dex group (59.8% vs 29.0%, p<0.001), with a higher incidence of atropine administration (18.1% vs 4.8%, p<0.001). Dexmedetomidine use was independently associated with bradycardia (odds ratio [OR] 5.16; 95% confidence interval [CI] 2.57-10.39; p<0.001). Notably, dexmedetomidine significantly reduced intraoperative requirements for midazolam (median 0.038 vs 0.044 mg/kg/h; p<0.001) and propofol (median 0.73 vs 1.25 mg/kg/h; p<0.001). Younger age (OR 0.97 per year; 95% CI, 0.96-0.99; p<0.001) and longer anesthesia duration (OR 1.04 per minute; 95% CI, 1.02-1.06; p<0.001) were additional predictors of bradycardia. Age-stratified analyses revealed a more pronounced reduction in heart rate among younger patients (< 45 years) receiving dexmedetomidine, suggesting an age-dependent modulation of the bradycardic response. Conclusion: Although dexmedetomidine use was associated with a higher incidence of intraoperative bradycardia, it provided meaningful anesthetic benefits during RF rhizotomy, including significant sedative-sparing effects and reduced exposure to other hypnotic agents. With appropriate monitoring and individualized dosing, particularly in younger patients, dexmedetomidine remains a safe and valuable sedative option for trigeminal neuralgia procedures.