Guillotine performance: duty cycle analysis of vitrectomy systems.

Authors :: Magalhaes O Jr
Chong L
DeBoer C
Bhadri P
Kerns R
Barnes A
Fang S
Schor P
Humayun M
Source :: Retinal cases & brief reports [Retin Cases Brief Rep] 2009 Winter; Vol. 3 (1), pp. 64-7.
Publication Year :: 2009
Abstract: Purpose: To evaluate the duty cycle of different vitrectomy cutters and classify their blade movement.<br />Methods: A precise weighing (0.01 g) high speed (2 samples/s) balance was used to study the 20-gauge and 25-gauge Bausch & Lomb Lightning-Millenium (St. Louis, MO), the 20-gauge (1500 cpm) and the 25-gauge Alcon Accurus (Fort Worth, TX), the 20-gauge Alcon Innovit, and the 23-gauge DORC (Netherlands) cutters. The weight of balanced saline solution (BSS) was recorded in real time using LabView software and then translated into a graph of volume removed versus time. Variable cut rates and vacuum pressures were analyzed in vitreous and BSS. A high-speed (400 frames/s) camera was used to record cutting for each condition.<br />Results: Three types of duty cycle were investigated: parabolic incomplete (pneumatic), sinusoid (electric), and trapezoid (double pneumatic). The parabolic incomplete and trapezoid had a decreased duty cycle at 1500 cuts per minute when it was compared to 600 cuts per minute. The sinusoid had no statistical difference between cut rates.<br />Conclusions: Systems showed different performances of duty cycle. This new classification will be useful for improved understanding of vitrectomy in these different systems.