Correspondence

Abstract

While anesthesia for cataract surgery is going toward intraocular drug delivery, we believe that sub-Tenon's anesthesia could replace peribulbar needle injections when more invasive surgery has to be performed, as in combined surgery for cataract and glaucoma. In these eyes, our technique of sub-Tenon's anesthesia starts with 2 drops of lidocaine 4% to obtain surface analgesia. Then, 30 mg of mepivacaine in 1.5mL are injected by a plastic cannula 1 into the sub-Tenon's space near the superior rectus muscle, through a conjunctival limbal incision eventually enlarged to a fornix-based conjunctival flap. Soon after injection, the bridle suture under the superior rectus muscle can be passed without difficulty. The conjunctival chemosis rapidly subsides as the conjunctival incision is enlarged to a conjunctival flap. Trabeculectomy and phacoemulsification are performed through the same or a separate incision, according to the surgeon's technique. We reviewed the charts of the first 50 patients we operated on for cataract and glaucoma by combined surgery with sub-Tenon's anesthesia, comparing the intraoperative and postoperative complications with those of the last 50 patients operated on using peribulbar needle anesthesia. In only 1 eye was the sub-Tenon's anesthesia enhanced by a second injection. The intraoperative complications in the sub-Tenon's and peribulbar groups did not differ: capsulorhexis rupture, 3 and 2; posterior capsule rupture, 1 and 2; minor iris damage, 7 and 8. Scleral fixation of the intraocular lens was performed in 1 eye in the sub-Tenon's group, without additional anesthesia, and in no eye in the peribulbar group. Postoperative complications also occurred in similar percentages: hyphema, 12% and 6%; fibrinous reaction in the anterior chamber, 16% and 18%; choroidal detachment, 6% and 4%; corneal edema lasting more than 3 days, 6% and 10%. Six months after surgery, intraocular pressures were also similar. This experience supports the opinion that combined cataract and glaucoma surgery can be performed under both types of anesthesia with similar results. However, sub-Tenon's anesthesia carries no risk of penetrating the eye and delivers a smaller amount of drug. Patients were pleased with this “no-needle” technique. In our opinion, it should be adopted extensively in anterior segment procedures involving conjunctival and scleral manipulation that are badly handled by topical anesthesia application. Roberto Bellucci MD Simonetta Morselli MD Vincenzo Pucci MD Silvia Babighian MD Verona, Italy