Comparative study between dexmedetomidine vs. neostigmine as adjuvants to local anesthetic mixture for peribulbar block for vitreoretinal surgeries

Background & objective: Peribulbar block is a widely used technique for vitreoretinal surgeries due to its safety and efficacy. Adding adjuvants to local anesthetics is known to enhance the quality of the block and prolong the duration of its effect. In this study, we compared the effectiveness of dexmedetomidine and neostigmine as adjuvants to local anesthetic in peribulbar blocks for vitreoretinal surgeries. Methodology: This prospective, randomized, controlled, blinded study was conducted on patients undergoing vitreoretinal surgery under peribulbar block. Patients were randomized into three groups: Group D received dexmedetomidine 25 µg, Group N received neostigmine 0.5 mg, and Group C served as control group with normal saline. Results: The duration of analgesia was significantly longer with Group D (182.4 ± 4.9 min), followed by Group N (171.7 ± 4.2 min), and Group C (175.0 ± 9.2 min) (P < 0.001). Also, the duration of motor block was significantly longer with Group D (160.0 ± 4.2 min), followed by Group N (156.3 ± 3.3 min) and Group C (151.3 ± 7.2 min) (P <.001). Conclusion: Dexmedetomidine as an adjuvant to local anesthetic in peribulbar blocks provides a faster onset and prolonged duration of sensory and motor block compared to neostigmine. Keywords: Peribulbar Block; Dexmedetomidine; Neostigmine; Local Anesthesia; Vitreoretinal Surgery; Regional Anesthesia Citation: Seleem HHG, Kamel GF, Wahba SS, El-Gendy MA, Hafez AF. Comparative study between dexmedetomidine vs. neostigmine as adjuvants to local anesthetic mixture for peribulbar block for vitreoretinal surgeries. Anaesth. pain intensive care 2025;29(3):444-450. DOI: 10.35975/apic.v29i3.2756 Received: February 18, 2025; Revised: March 20, 2025; Accepted: March 23, 2025