IntroductionSutureless 25-gauge pars plana vitrectomy has the potential to reduce the length of surgery and postoperative inflammation at the sclerotomy sites, thus decreasing patient discomfort postoperatively and hastening recovery (Chen 1996;Kwok et al. 1999;Jackson 2000;Lam et al. 2000;Rahman et al. 2000;Fujii et al. 2002a).This technology for vitrectomy, first described by De Juan & Hickingbotham (1990), has changed to facilitate transconjunctival sutureless vitrectomy (Fujii et al. 2002b). Smaller instrumentation has resulted in decreased infusion and aspiration rates, which may increase surgical time (Fujii et al. 2002b).Changes in pressure, resistance and cut rates with the smaller systems result in different types of vitrectomy. Many critical intraoperative situations in which the surgeon must select ideal surgical parameters require a solid comprehension of 25-gauge fluid dynamics.The purpose of the current study was to evaluate in vitro the infusion, aspiration and cutting rates of different 25-gauge vitrectomy systems to determine their respective physical characteristics during vitreoretinal surgery.
Materials and MethodsThe infusion and aspiration rates of three 25-gauge systems made by Alcon Laboratories Inc. (Fort Worth, TX, USA), Bausch & Lomb Inc. (St Louis, MO, USA), and the Dutch Ophthalmic Research Centre (DORC, Zuidland, the Netherlands), respectively, were measured in vitro using a chronometer with 0.01-second accuracy. A precise weighing (to 0.01 g) high-speed (two samples ⁄ second) Ohaus Corporation balance (Pine Brook, NJ, USA) was used to measure 10 ml in a highaccuracy volume bottle. A stopwatch Wenzhou Lianying Teaching Instrument Co. Ltd precise chronometer (Wenzhou, China) was turned on and off when target weights (difference of 10 ml in balance) were showed.
Infusion ratesThe infusion rates of 10 ml of balanced saline solution (BSS) were measured