Local Anesthesia With Blunt Sub-Tenon's Cannula Versus Sharp Retrobulbar Needle for Vitreoretinal Surgery: A Retrospective, Comparative Study.

Background and Objective: To evaluate the safety and efficacy of a blunt sub-Tenon's cannula for local anesthesia before vitreoretinal surgery compared to a sharp retrobulbar needle.
Patients and Methods: Retrospective, comparative study of all patients undergoing vitreoretinal surgery at the Medical College of Wisconsin between August 2009 and November 2013. Institutional review board approval was obtained.
Results: Of 940 surgeries performed with a sub-Tenon's cannula, 99% (938 of 940) were completed. Of the 771 surgeries performed with a sharp retrobulbar needle, 99% (770 of 771) were completed. Factors associated with use of a sharp retrobulbar needle over sub-Tenon's cannula were presence of prior scleral buckle (P < .01) and inclusion of scleral buckle placement in the procedure (P < .01). No case of globe perforation, severe retrobulbar hemorrhage, or severe conjunctival chemosis was observed in either group.
Conclusion: Blunt sub-Tenon's cannula appears as effective and safe as a sharp retrobulbar needle for local anesthesia during vitreoretinal surgery. Vitreoretinal surgeons may wish to consider a blunt sub-Tenon's cannula for local surgical anesthesia.
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