Reply

Abstract

Grzybowski and Kanclerz insightfully highlight valuable information regarding the referenced studies demonstrating higher rates of vitreous incarceration in sutureless sclerotomies in PPV and the potential reduction of this risk by attentive shaving of the vitreous base in these localized areas. This seems a valuable maneuver in three-port vitrectomy in the setting of vitreoretinal pathology. We believe that anterior vitrectomy via the pars plana is a fundamentally different procedure, albeit with great similarities. Anterior vitrectomy through the pars plana is aimed at eliminating gel from the anterior segment while preserving as much native anterior segment structure as possible. Eller and Barad1 have shown that in this setting, maximum safety is achieved by avoiding vitrectomy beyond the iris root. These cases are rarely performed in a setting in which a vitreous base shaving is practical. Whether direct sclerotomy or cannula and trocar systems are superior in this setting remains untested in a compared trial (though we still firmly believe that the trocar and cannula system is an easier, better, and safer choice). We fully agree that avoiding flow through the cannula as it is being removed reduces the risk for vitreous incarceration in the sclerotomy. This can be achieved by having an instrument or plug in the lumen (as Drs. Grzybowski and Kanclerz point out), or by using a valved cannula, which prevents outward flow. We endorse the use of one of these mechanisms. In addition, for the anterior segment surgeon, our machines typically allow us to turn irrigation on and off by foot switch, and we simultaneously turn off irrigation as the cannula is removed, further reducing the risk for active displacement of vitreous into a sclerotomy during cannula removal before it has the chance to seal. We are pleased with and proud of our very low incidence of endophthalmitis. We do not regularly use intracameral or infusional antibiotics. We do use topical antibiotics starting 2 days before surgery and for 1 week thereafter. We use both preoperative and postoperative povidone–iodine prophylaxis, and our surgery center personnel and surgeons maintain extraordinary attentiveness to sterile techniques. In fairness, the historically higher reported risk for endophthalmitis in anterior vitrectomy cases might be related to cases in which vitrectomy was unplanned and untoward events were already underway. Vitrectomy was performed on a planned basis in the overwhelming majority of our cases. We strongly endorse the use of triamcinolone staining of the vitreous first described by Burk et. al. (of which one of us is a coauthor),2 although concede that this was used very infrequently in this cohort because the index surgeon (M.E.S.) has a high level of confidence in the optics of our microscopes and the subtle signs of vitreous. We also attribute the excellent anterior chamber clearance of vitreous gel to the anterior-to-posterior flow gradient that a single-port PPV with an anterior chamber infusion affords. Most cases of anterior vitrectomy in this cohort had concomitant risk factors for glaucoma and steroid response; thus, triamcinolone was used sparingly in this cohort.