Efficacy and Safety of Magnesium versus Dexmedetomidine as Additives to Local Anesthetic Mixture Using Single Injection Percutaneous Peribulbar Anesthesia in Vitreoretinal Surgeries

Peribulbar block for vitreoretinal surgery is rather associated with delayed onset of globe anesthesia, akinesia and short duration of analgesia.

To compare the effect of addition of Magnesium sulphate vs dexmedetomidine to standard local anesthetics mixtures on the time of onset of Globe Anesthesia, Akinesia & analgesia duration.

Ninety patients of both sexes, aged 25- 75 years, ASA I-III scheduled for vitreoretinal surgery. They were randomly allocated into 3 equal groups each received peribulbar block a mixture of Levo- bupivacaine 0.5% (3 ml) + lidocaine 2% (3 ml) +120 IU hyaluronidase + Control group (C): 0.5 ml of Normal saline. Group (M): 50 mg of Magnesium sulphate in 0.5 ml normal saline. Group (D): 50 μic of dexmedetomidine in 0.5 ml normal saline. The duration of sensory, motor block, Sedation level, Intra-ocular Pressure (IOP) and surgeon satisfaction were assessed.

The onset of globe anesthesia and akinesia was significantly shorter in M group in comparison with D and C Groups, with a significant increase in the duration of globe analgesia and akinesia in the D Group when compared to both M & C groups. Groups D and M showed a statistically significant decrease in the IOP at 5 min and 10 min when compared to the baseline measurement of the same groups & to C Group, no complications or adverse effects related to the drug or technique were recorded.

Magnesium sulphate as a local anesthetic adjuvant in peribulbar block is safe and comparable to dexmedetomidine regarding the sensory and motor block duration with better cost-effectiveness and availability.