Dose-Response Evaluation of Intrathecal Dexmedetomidine with Low-Dose Hyperbaric Levobupivacaine for Geriatric Urological Surgery: A Randomized Double-Blind Trial

Background: The ideal intrathecal adjuvant in elderly patients should prolong postoperative analgesia while maintaining hemodynamic stability and facilitating smooth recovery. This study compared three doses of intrathecal dexmedetomidine combined with low-dose hyperbaric levobupivacaine in geriatric patients undergoing elective urological surgery. Methods: In this prospective, randomized, double-blind study, 66 ASA I-II patients aged 60-82 years were allocated into three groups (n=22 each). All patients received 2.2 ml of 0.5% hyperbaric levobupivacaine with dexmedetomidine 5 µg (Group A), 7.5 µg (Group B), or 10 µg (Group C). The primary outcome was duration of postoperative analgesia. Secondary outcomes included onset and duration of sensory and motor blockade, Visual Analogue Scale (VAS) scores, rescue analgesic consumption, sedation scores, hemodynamic parameters, and adverse events. Preoperative geriatric assessment included Activities of Daily Living, Mini-Mental State Examination, and Clinical Frailty Scale. Results: Baseline demographic and geriatric assessment parameters were comparable among groups. Group C demonstrated significantly faster sensory block onset (1.08±0.42 min) and longer postoperative analgesia (181.37±9.79 min) than Groups A and B (p < 0.001). Postoperative VAS scores and rescue analgesic requirements were significantly lower in Group C. Sedation scores were slightly higher in the early postoperative period in Group C; however, hemodynamic and respiratory parameters remained stable, with no significant increase in adverse effects. Conclusion: Intrathecal dexmedetomidine improved spinal anaesthesia quality in a dose-dependent manner. A 10 µg dose provided superior postoperative analgesia with reduced analgesic requirement and acceptable safety in elderly patients undergoing urological surgery.