First Author: D.Abulon USA
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In order to optimize surgical outcomes, it is important to fully understand instrument performance during vitrectomy. This study characterizes porcine vitreous flow rates associated with 23-gauge dual-pneumatic probes under various duty cycle modes and high-speed cut rates (up to 10,000 cpm).
In-vitro laboratory testing of porcine cadaver vitreous flow rates.
The CONSTELLATION® Vision System was tested with Advanced UltraVit® vitrectomy probes at 450 mmHg vacuum (Alcon Laboratories, Inc.). Six 23-gauge probes were evaluated at three duty cycle modes (ie, port biased open, 50% port open time, port biased closed) and at various cut rates (ie, 2500, 5000, 7500, and 10,000 cpm). Harvested porcine vitreous was placed on an electronic balance (Mettler Toledo MS 2014S) and volume of removed vitreous was measured during simulated vitrectomy. Average vitreous flow rates were calculated using the change in weight and duration of aspiration.
In the biased-open duty cycle mode at 450 mmHg vacuum, the vitreous flow rates of 23-ga probes increased from 3.16±0.39 to 3.33±0.21 cc/min as cut rate increased from 2,500 to 10,000 cpm. With the 50% port open duty cycle, vitreous flow rates also increased as cut rate increased from 2.44±0.24 cc/min at 2500 cpm to 3.41±0.16 cc/min at 10,000 cpm. In the biased-closed duty cycle, vitreous flow rates increased from 2.03±0.56 cc/min at 2500 cpm to 3.23±0.37 cc/min at 10,000 cpm. For all three duty cycle modes, maximum vitreous flow was observed at the 10,000 cpm cut rate setting.
Vitreous flow rates generally increased with increasing cut rates for all duty cycle modes. Vitreous aspiration of high-speed dual-pneumatic 23-gauge vitrectomy probes appear to be most efficient at the maximum cut rate of 10,000 cpm.