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Dina Joy K Abulon, Tingting Wang; Reduced Vitreous Traction Associated with 23-Gauge Dual Pneumatic High Speed Cutters. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):396.
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© ARVO (1962-2015); The Authors (2016-present)
To quantify and compare traction forces between 2500 cuts per minute (cpm), 5000cpm, and 7500cpm with dual pneumatic vitrectomy probes in an ex- situ porcine eye model.
A mechanical force measurement system was developed to quantify traction forces applied to the vitreous by a vitrectomy cutter. Traction measurements were performed in an ex-situ test set up using vitreous harvested from fresh porcine eyes. To minimize variability of vitreous tissue, traction was measured with the same vitreous mass by alternating between three cut rates (2500cpm, 5000cpm, and 7500cpm) and maintaining the same aspiration level (300mmHg), under 50/50 duty cycle. A total of 6 UltraVit® 23-Gauge (Ga) vitrectomy cutters and 30 porcine eyes (N=30) were tested. Peak traction forces and mean traction forces for each cut rate were averaged from each test. Significant differences in traction forces between cut rates were determined using a paired t-test and analysis of variance with p<0.05 as the statistical significance level.
The 2500cpm cut rates created the highest vitreous traction peak force of 1.17±0.36mN, and a mean force of 0.47±0.11mN. 5000cpm created less traction with a peak force of 0.86±0.27mN, and a mean force of 0.46±0.10mN. 7500cpm generated the least traction among the three with a peak force of 0.66±0.21mN, and a mean force of 0.39±0.09mN. Peak and mean traction forces of 7500cpm were significantly smaller than 5000cpm (-0.20mN, p<0.0001; -0.06mN, p<0.001), and 2500cpm (-0.51mN, p<0.0001; -0.08mN, p<0.0001). When comparing the relative reduction in force, the peak force of 7500cpm was 74% and 54% of 5000cpm and 2500cpm respectively (p<0.001); the mean force of 7500cpm was 85% and 80% of 5000cpm and 2500cpm(p<0.001) respectively. Pure vitreous flow tests revealed increased vitreous flow at 7500cpm as compared to 5000cpm and 2500cpm.
Compared to lower cut rates, the high speed dual pneumatic probes operating at 7500cpm may improve vitrectomy surgery by generating less vitreous traction and more efficient vitreous removal.
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