Extensibility and scanning electron microscopy evaluation of 5 pediatric anterior capsulotomy techniques in a porcine model

Abstract

PURPOSE: To compare the extensibility and scanning electron microscopy (SEM) of 5 currently used pediatric anterior capsulotomy techniques: vitrectorhexis, manual continuous curvilinear capsulorhexis (CCC), can-opener, radio frequency diathermy, and plasma blade in a porcine model. SETTING: Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Extensibility was determined by stretching each capsulotomy until it ruptured and measuring it by calculating the mean stretch-to-rupture circumference of each capsulotomy (20 eyes per technique) as a percentage of its baseline circumference. Edge characteristics were evaluated using SEM. RESULTS: The mean extensibility of each technique tested (vitrectorhexis 161%, CCC 185%, can opener 149%, radio frequency 145%, plasma blade 170%) was significantly different (P<.001, 1-way analysis of variance). The SEM examination found that the vitrectorhexis had a scalloped edge with the whole edge rolled over, presenting a smooth surface toward the inside of the capsulotomy; the manual CCC produced the smoothest edge, with no irregularities noted; the can-opener edge was irregular, showing each puncture of the needle had created a small arc, with occasional regions of the edge rolled over in a “hit-and-miss” fashion; the radio-frequency diathermy capsulotomy edge was ragged, rough, and irregular; and the plasma blade capsulotomy edge was rougher than the manual CCC, but there were fewer irregularities than the radio-frequency diathermy edge had. CONCLUSIONS: The manual CCC technique produced the most extensible porcine capsulotomy, followed by the plasma blade, vitrectorhexis, can-opener, and radio-frequency techniques, in a porcine model. The manual CCC technique also produced the smoothest anterior capsulotomy edge according SEM evaluation.