Purpose
Local anesthesia using sharp retrobulbar needle can be associated with complications. We compare safety and efficacy of blunt subtenon cannula for administering local anesthesia before vitreoretinal surgery to anesthetic delivered by a sharp retrobulbar needle.
Methods
This was a retrospective, comparative study of all patients undergoing local anesthesia before vitreoretinal surgery at the Medical College of Wisconsin between August 2009 and November 2013. Local anesthesia administered either via blunt subtenon cannula or sharp retrobulbar needle prior to vitreoretinal surgery. The incidence of local and systemic anesthesia-related complications as well as the incidence of inadequate local surgical anesthesia requiring conversion to general anesthesia was recorded.
Results
Blunt subtenon cannula was used in 940 cases while sharp retrobulbar needle was used in 771 cases for local anesthesia. Factors associated with use of sharp retrobulbar needle over subtenon cannula were presence of prior scleral buckle and inclusion of scleral buckle placement in the procedure. Of 940 surgeries performed with subtenon’s cannula, only 2 cases were not completed, due to ether suprachoroidal hemorrhage (1 case) or sleep-apnea-related hypoxia (1 case). Of 771 surgeries performed with sharp retrobulbar needle, only 1 case was not completed, due to suprachoroidal hemorrhage (1 case). Intraoperative conversion to general anesthesia was required after subtenon cannula in 9 patients and after retrobulbar needle in 12 patients. No case of globe perforation, severe retrobulbar hemorrhage, or severe conjunctival chemosis was observed in either group.
Conclusions
Blunt subtenon cannula appears as effective and safe as sharp retrobulbar needle for administering local anesthesia prior to vitreoretinal surgery. Vitreoretinal surgeons may wish to consider using a blunt subtenon cannula for local anesthesia during vitreoretinal procedures.