A Comparison of Retrobulbar, Sub-Tenon's Anesthesia and Medial Canthus Episcleral Anesthesia for 25-Gauge Posterior Vitrectomy.

PURPOSE The aim of the study is to compare the efficacy, safety and globe akinesia between retrobulbar anesthesia, Sub-Tenon's anesthesia and medial canthus episcleral anesthesia for 25-Gauge posterior vitrectomy. METHODS A total of 340 25-Gauge vitrectomy data sheets were retrospectively collected between November 2017 and June 2019. Ninety patients were included in the study. These patients were matched by sex and age to receive retrobulbar anesthesia (Group 1, n=30), Sub-Tenon's anesthesia (Group 2, n=30) and medial canthus episcleral anesthesia (Group 3, n=30). Globe akinesia was recorded after the injection of anesthetic at 2, 5 and 10 minute time intervals. Patients were asked to rate the pain during administration of anesthesia, during surgery, and postoperatively using the visual analogue pain scale. RESULTS In terms of a perfect block, at 10 minutes retrobulbar outperformed both Sub-Tenon's and medial cantus episcleral anesthesia which appeared quite similar. During administration, the three techniques did not show statistically different effects on pain. Regarding perioperative pain, retrobulbar outperformed medial cantus episcleral anesthesia. CONCLUSIONS All three techniques allowed for safe surgery. Retrobulbar obtained the best results, even though Sub-Tenon's proved to be a valid alternative. Medial cantus episcleral anesthesia obtained mostly good and fair blocks and acceptable pain levels during surgery. Further studies should investigate whether optimal anesthetic efficacy can obtained with Sub-Tenon's and medial cantus episcleral techniques when higher volumes are used.