Subtenon Block Combined With General Anesthesia for Vitreoretinal Surgery

Under general anesthesia and the operating microscope, a Lieberman lid speculum was placed and the conjunctiva was cleaned with 4% povidone iodine solution. The surgeon then created a fornix-based incision through conjunctiva and tenon's tissue inferonasally midway between the insertions of the medial and inferior rectus muscles, with blunt Wescott scissors to expose the scleral surface before tunneling posteriorly with curved Stevens scissors to create a small channel to the posterior subtenon space. A blunt-tipped subtenon cannula was then inserted into the posterior subtenon space, 4mL of 2% lidocaine and 0.5% bupivacaine (50:50) mixture versus saline was introduced and the drug solution was injected slowly into the subtenon space. After administration of local anesthetic mixture, the eyelid was gently taped down, and no ocular massage was performed