PURPOSE: To evaluate porcine vitreous flow and balanced saline solution (BSS) flow rates in different vitrectomy systems. METHODS: Porcine vitreous was obtained within 24 hours of slaughter. A high-speed (2 samples/s) balance, precise to 0.01 g, was used. Variable cut rates and vacuum pressures were analyzed in vitreous and BSS. The vitreous was labeled with glass microspheres and triamcinolone acetonide. A high-speed (400 frames/s) camera was used to record cutting for each condition. RESULTS: For all cutters, there was no vitreous flow at zero cut rates (off). In 25-gauge cutters, at 500 mmHg of vacuum, the electric cutter produced higher average flow rates at high cut rates (600 cpm, 0.004 mL/s, and 1500 cpm, 0.013 mL/s) than pneumatic, which demonstrated a decreased flow at speeds higher than 1000 cpm (1000 cpm, 0.015 mL/s, and 1500 cpm, 0.006 mL/s). The percentage of vitreous flow rate/BSS flow rate in different aspiration and cut rates showed an ascending curve. This demonstrates evidence of flow obstruction in 25- (all cut rates), 23- (all cut rates), and 20-gauge (all cut rates). Flow obstruction and surge movements were seen in the high-speed videos. CONCLUSIONS: The vitrectomy systems each illustrate different performances of vitreous removal. The physical characteristics of vitreous resulted in nonuniform flow in all vitreous cutters.
PURPOSE: To evaluate porcine vitreous flow and balanced saline solution (BSS) flow rates in different vitrectomy systems. METHODS: Porcine vitreous was obtained within 24 hours of slaughter. A high-speed (2 samples/s) balance, precise to 0.01 g, was used. Variable cut rates and vacuum pressures were analyzed in vitreous and BSS. The vitreous was labeled with glass microspheres and triamcinolone acetonide. A high-speed (400 frames/s) camera was used to record cutting for each condition. RESULTS: For all cutters, there was no vitreous flow at zero cut rates (off). In 25-gauge cutters, at 500 mmHg of vacuum, the electric cutter produced higher average flow rates at high cut rates (600 cpm, 0.004 mL/s, and 1500 cpm, 0.013 mL/s) than pneumatic, which demonstrated a decreased flow at speeds higher than 1000 cpm (1000 cpm, 0.015 mL/s, and 1500 cpm, 0.006 mL/s). The percentage of vitreous flow rate/BSS flow rate in different aspiration and cut rates showed an ascending curve. This demonstrates evidence of flow obstruction in 25- (all cut rates), 23- (all cut rates), and 20-gauge (all cut rates). Flow obstruction and surge movements were seen in the high-speed videos. CONCLUSIONS: The vitrectomy systems each illustrate different performances of vitreous removal. The physical characteristics of vitreous resulted in nonuniform flow in all vitreous cutters.
Authors: Mikel Mikhail; Andre Ali-Ridha; Sarah Chorfi; Michael A Kapusta Journal: Graefes Arch Clin Exp Ophthalmol Date: 2017-07-15 Impact factor: 3.117
Authors: Mikel Mikhail; Andre Ali-Ridha; Sarah Chorfi; Michael A Kapusta Journal: Graefes Arch Clin Exp Ophthalmol Date: 2016-08-02 Impact factor: 3.117
Authors: Bruno Diniz; Rodrigo B Fernandes; Ramiro M Ribeiro; Jaw-Chyng Lue; Anderson G Teixeira; Octaviano Magalhães; Mauricio Maia; Mark S Humayun Journal: Retina Date: 2013-05 Impact factor: 4.256
Authors: Bruno Diniz; Ramiro M Ribeiro; Rodrigo B Fernandes; Jaw-Chyng Lue; Anderson G Teixeira; Mauricio Maia; Mark S Humayun Journal: Ophthalmologica Date: 2012-10-27 Impact factor: 3.250