Comparing intrathecal dexmedetomidine versus midazolam in orthopedic cancer surgeries: a prospective randomized controlled trial

Background & objectives: The anesthetists have been trying various adjuvants with local anesthetic agents for spinal anesthesia to prolong the duration of analgesia and to reduce the associated side effects. This study was aimed to evaluate the effect of dexmedetomidine versus midazolam when added to the intrathecal bupivacaine. Methods: Seventy-five adult patients, 20 to 70 y of age, scheduled for orthopedic cancer procedures under the spinal anesthesia, were enrolled in this research trial. Selected patients were randomly divided into three equal groups; Group D (Dexmed Group): 25 patients received spinal anesthesia with 0.5% bupivacaine 3.5 mL plus dexmedetomidine 5 μg in saline 0.5 mL; Group M (Midazolam Group) 25 patients received 0.5% bupivacaine 3.5 mL plus midazolam 2 mg in 0.5 mL normal saline, and the third group Group C (Control Group) comprising of 25 patients received 0.5% bupivacaine 3.5 mL plus 0.5 mL normal saline. The primary outcome of this study was duration of the sensory block. Secondary outcomes were duration of the motor block. Results: We employed two segments of time. The median duration of the dexmedetomidine group was 132 min, which is statistically significant compared to the midazolam group (119 min) and the control group (98 min). The motor block was also significantly prolonged in the Dexmed Group compared to the midazolam group and the control group. However, dexmedetomidine and midazolam groups showed significant hypotension compared to the control group. Conclusion: Dexmedetomidine has a longer sensory and motor block effect than midazolam, when added to the spinal bupivacaine; both dexmedetomidine and midazolam groups have longer duration than the control group. Dexmedetomidine can be recommended for prolonged orthopedic cancer surgeries, due to its prolonged postoperative analgesia despite the associated hypotension. Abbreviations: GABA: gamma-aminobutyric acid. gamma-aminobutyric acid, MAP: mean arterial pressure. Keywords: Intrathecal Dexmedetomidine; Intrathecal Midazolam; Hyperbaric Bupivacaine; Spinal Anesthesia, Hypotension Citation: Zedan M, Elwasseef M, Shaker EH, Mohamed Turki DA, Kamel MA. Comparing intrathecal dexmedetomidine versus midazolam in orthopedic cancer surgeries: a prospective randomized controlled trial. Anaesth. pain intensive care 2025;29(2):185-193. DOI: 10.35975/apic.v29i2.2702 Received: September 24, 2024; Reviewed: October 26, 2024; Accepted: January 25, 2025