Fluidic performance of a dual-action vitrectomy probe compared with a single-action probe

Abstract

Purpose:To assess flow rates, nearfield effects, and traction of a dual-cutting 20,000 cpm vitrectomy probe (HYPERVIT, Alcon) versus a single-cutting 10,000 cpm probe (Advanced ULTRAVIT, Alcon).Methods:Flow rates were evaluated for 25+ and 27+ gauge probes using balanced salt solution or porcine cadaver vitreous (biased open, 50/50, and biased closed duty cycles). Probes were suspended in an open beaker, and flow rates were calculated using a precision balance. Nearfield effects and flow pulsatility were assessed using a validated simulation model based on experimental microparticle image velocimetry. Traction was assessed by attaching vitreous to a cantilever beam and measuring the deflection of the beam.Results:For HYPERVIT probes, aqueous flow rates were similar across all cutting rates. Vitreous flow rates increased with increasing cutting rates. At maximum cutting rates, aqueous flow was 62%-67% greater (25+) and 63% greater (27+) with HYPERVIT versus Advanced ULTRAVIT (P < 0.05); vitreous flow was 44%-47% greater (25+) and 26%-32% greater (27+) with HYPERVIT versus Advanced ULTRAVIT (P < 0.05). Nearfield effects were reduced, and peak traction forces were significantly lower for HYPERVIT versus Advanced ULTRAVIT (P < 0.05).Conclusion:Significantly greater aspiration flow, reduced nearfield effects, and reduced traction were observed with dual-action versus single-action probes.