Abstract
Purpose :
This study seeks to determine the relative and maximum flow rates achieved during the removal of porcine vitreous between a tradition guillotine-based (GV) vitrectomy device and a novel, open-port, hypersonic vitrectomy (HV) unit through optimized vacuum, cut rate and stroke length settings
Methods :
Open-sky vitrectomies were performed on porcine cadaver eyes using a 23 ga GV vitrectomy handpieve and a 23 ga HV handpiece affixed to a Venturi-vacuum driven platform. Vacuum, cut rate and stroke length (distance the needle tip oscillates when active) were titrated to optimize vitreal flow rates for both systems. Stroke for the HV is defined as the . Flow rates were calculated by determining average weight differential before and after performing vitrectomies for 30 seconds on each system (HV = 3, GV = 3)
Results :
Maximum stroke length of 60 µm and 600 mmHg vacuum generated a maximal vitreal flow rate of 5.93 ± 0.75 mL/min with HV. GV achieved the highest vitreal flow rate of 4.89 ± 0.33 mL/min at 500 cpm and 600 mmHg vacuum. HV vitreal flow rate increased linearly with increased vacuum and stroke length. GV exhibited threshold vitreal flow rate at 500 cpm with a reduction in flow observed with higher cut speed. These differences in flow can be attributed partially to design differences between the two cutters. The HV the unique single-lumen design provides completely unobstructed thereby allowing 100% duty cycle. The GV’s needle in needle design partially occludes the port during cutting, thereby decreasing the effective duty cycle. This leads to increased occlusion and lower flow as cut rate increases
Conclusions :
HV shows linear vitreous removal as stroke rate and vacuum are increased. The 100% duty cycle has the potential to allow surgeons to take advantage of high effective cut rates and may improve the efficacy of current vitrectomy techniques involving pneumatic guillotine cutters
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.