Outcomes and Adverse Events of Sub-Tenon's Anesthesia with the Use of a Flexible Cannula in 35,850 Refractive Lens Exchange/Cataract Procedures.

purposeTo describe our technique of sub-Tenon's anesthesia and report adverse events and patient comfort.

settingOptical Express, United Kingdom.

designRetrospective case series.

methodsThe outcomes of 35,850 intraocular procedures (phacoemulsification and implantation of an intraocular lens) were retrospectively reviewed and the incidence of adverse events related to sub-Tenon's anesthesia was calculated. On the first postoperative day, patients were asked to complete a questionnaire enquiring about their comfort during and after the procedure. The anesthetic solution consisted of a combination of Lidocaine and Hyaluronidase, which was administered into sub-Tenon's space with a single-use sterile polyurethane 22G x 1" (0.9 x 25 mm) cannula. Mild conscious sedation (midazolam) was used during anesthetic and surgical procedure.

resultsNo significant adverse events that would affect the posterior segment of the eye or result in vision loss were recorded. Subconjunctival haemorrhage related to sub-Tenon's anesthesia was noted in 4.3% of eyes. Five minutes after the administration of sub-Tenon's block, 80.6% of eyes had no chemosis, 14.8% had chemosis that affected only 1 quadrant of the eye and 4.5% of eyes had chemosis affecting 2 or more quadrants of the eye. Other adverse events included 14 cases of cyst/granuloma formation in the area of sub-Tenon's incision and 7 eyes required suturing of the conjunctival cut. Of all patients, 93.2% experienced no or only mild discomfort during or after surgical procedure.

conclusionSub-Tenon's anesthesia with the use of a flexible cannula is a safe option for ophthalmic anesthesia. No sight-threatening adverse events occurred.