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S. Fang, C. DeBoer, O. Magalhaes, Jr., J. Cicchella, R. Kerns, M. Humayun; Performance Analysis of MID Labs Adaptable Vit Enhancer (AVE) Vitrectomy Cutters Through Vitreous Removal Rates, Duty Cycle, Shaft Rigidity, and High-Speed Video. Invest. Ophthalmol. Vis. Sci. 2007;48(13):6031.
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© ARVO (1962-2015); The Authors (2016-present)
Smaller gauge vitrectomy cutters pose significant challenges in vitreous removal. Herein, we evaluate the performance of new AVE cutters relative to existing cutters.
Performance of 20 and 25-gauge MID Labs (San Leandro, CA) AVE cutters (n=24) was analyzed relative to 20-gauge Alcon (Fort Worth, TX) Accurus 2500 (n=12) and previously studied Alcon Innovit 20-gauge and Accurus 25-gauge, and Bausch & Lomb (St. Louis, MO) Lightning 20 and 25-gauge. Cutters were operated across each cutter’s specified cut speed range under constant aspiration of 200 mmHg for 20-gauge and 500 mmHg for 25-gauge. A precision (0.01 g) Ohaus (Pine Brook, NJ) balance was used to measure the mass of water or vitreous removed from a vial by a cutter, which was recorded in real-time and converted into flow rates. Porcine vitreous was harvested en bloc within 24 hours of slaughter. Frame-by-frame analysis of high-speed (1088 frames per second) video of cutter action was used to determine duty cycle as a function of speed. Shaft rigidity of 25-gauge probes was determined by measuring force exerted at the tip as a function of deflection. Data was analyzed statistically using regression analysis and two-tailed t-tests.
Rate of water removal by AVE cutters decreased with increasing cut speed more gradually than other spring-return pneumatic cutters, yielding higher flow rates at higher cut speeds. Rates of vitreous removal with AVE cutters were high, relatively constant across the cut speed range, and significantly greater than those of other same-gauge cutters at or above 1500 cuts per minute (CPM, p < 0.05). Vitreous flow rates of the 25-gauge AVE cutter were comparable to or higher than those of some 20-gauge probes. At 2000 and 2500 CPM, the 25-gauge AVE cutter exhibited vitreous flow rates 1.45 and 11.88 times that of the 20-gauge Accurus 2500 (p < 0.05), respectively. Duty cycles of both AVE cutters were high as compared with other cutters, ranging from 39-85% from 800-2500 CPM. Stiffness of AVE and Accurus 25-gauge cutter tips were equivalent (p > 0.05).
AVE 20- and 25-gauge cutters exhibit higher vitreous flow rates compared with existing cutters at high cut speeds (greater than or equal to 1500 CPM). Although many factors influence vitreous removal, AVE cutters exhibit relatively high and constant rates of vitreous removal likely due to their maintenance of high duty cycles across the tested cut speed range.
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