Comparative efficacy of mepivacaine vs. bupivacaine added to lignocaine plus hyaluronidase for percutaneous peribulbar injection in cataract surgery

Background: Peribulbar anesthesia had been developed as a safer, easier, and effective alternative to retrobulbar anesthesia that provides ocular akinesia and anesthesia. Objective: This study aimed to compare the efficacy of mepivacaine 3% - lidocaine 2% hyaluronidase mixture with that of bupivacaine 0.5% - lidocaine 2% - hyaluronidase to produce optimal operative and post-operative conditions in patients receiving single peribulbar injection for cataract surgery. Patients and Methods: In this randomized, double -blind study, 90 adult patients were assigned to one of two groups (M and B), each comprising 45 patients. Study participants received 6-8 ml combination of equal parts of either mepivacaine 3% (Group M) or bupivacaine 0.5% (Group B) both with lidocaine 2% and hyaluronidase 25 IU/ml. Akinesia was assessed with a 12-point scale at 2, 5, 10 and 15 min after injection. Onset of sensory block, time to start surgery, pain and requirement for supplemental injection were also assessed. Results: Group M showed better akinesia scores than Group B and the onset of globe akinesia and sensory block were significantly faster in Group M. The duration of globe and lid akinesia was longer in Group B (159.16 +/- 5.71 min and 150.02 +/- 4.42 min, respectively) than in Group M (142.89 +/- 6.52 min and 135.69 +/- 4.81 min, respectively) and this showed statistical significance (P < 0.001). The percentage of patients who required supplementary injection was significantly higher in Group B (7 patients) compared to that in Group M (2 patients). Conclusion: Using a mixture of mepivacaine and lidocaine gives perfect globe akinesia and quicker establishment of appropriate conditions to start cataract surgery and shortens the block onset time with faster recovery compared with the addition of bupivacaine to lidocaine in peribulbar anesthesia.