ANALYSIS OF PARS PLANA VITRECTOMY INCISIONS USING LIVE BACTERIA

To analyze small gauge pars plana vitrectomy sclerotomies using live bacteria transformed with green fluorescent protein (GFP).

Twenty-eight human cadaver eyes were specially harvested for this study. Small gauge vitrectomy was performed on each eye and the wounds were closed with various techniques (sutured, sutureless, and cauterization). Live Staphylococcus epidermidis that has been transformed with a green fluorescent protein was applied to the overlying conjunctival surface. Analysis of all vitreous samples was analyzed with confocal laser microscopy to identify the presence of bacteria. All wounds were analyzed histopathologically.

A high concentration of bacteria was noted in 2 of 3 eyes in the sutureless, 23-G perpendicular incision group postinoculation. There were no bacteria detected in any postvitrectomy sample that were closed with cautery or a beveled incision. No bacteria were found in postvitrectomy samples of sutureless 27-G perpendicular incisions and sutureless 27-G beveled incisions. Finally, there were no bacteria detected in both eyes with 23-G perpendicular incisions that had a partial air-fill.

Live bacteria can be effectively used to analyze wound integrity. Closing sclerotomy sites with cautery proved effective in a model using fresh, human cadaver eyes. 27-G perpendicular incisions may be just as competent as 27-G beveled incisions.