Purchase this article with an account.
Ramon C. Dimalanta, Aditi Ray, Dina Joy K. Abulon, Dave C. Buboltz; A Closed Surgical System with Valved Trocar Cannulas during Simulated Vitrectomy. Invest. Ophthalmol. Vis. Sci. 2012;53(14):2594.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
A closed surgical system has been the standard of care in cataract surgery. However in vitreo-retinal surgeries surgeons often have to employ an open-cannula system increasing the risk of fluid leakage during instrument exchange . A recently developed valved trocar cannula offers an alternative to the non-valved trocar cannulas. The present study investigates the performance of the valved and non-valved trocar cannulas of two different gauges under open cannula conditions in simulated vitrectomy.
Model eye globes were assembled with each globe containing either three 23G non-valved (N=3), three 23G valved (N=3), three 25G non-valved (N=3) or three 25G valved (N=3) cannulas. Balanced salt solution (BSS® irrigating solution) was infused into the eye globes at different infusion pressures (30mmHg, 60mmHg, 90mmHg, and 120mmHg) and IOP (intraocular pressure) compensation settings that are available on manufactured platforms with such control features. Instruments were withdrawn from either one or two ports of each globe to simulate an open cannula condition and corresponding changes in infusion flow rate and IOP were recorded.
For non-valved trocar cannulas, IOP decreased to approximately 30% of its original value with IOP compensation OFF and remained unaffected even when infusion pressure was increased. However in cases where IOP compensation was ON, the drop in IOP was not as immediate with the largest drop (17% and 16% of original IOP for 23G & 25G probes respectively) observed at the highest infusion pressure of 120mmHg. Also higher infusion flow rates were noted in cases where IOP compensation was ON compared to cases where it was OFF. Conversely, there was no such decrease in IOP in the case of valved trocar cannulas across all settings tested. Minimal fluid leakage (upto 1.4mL/min) was observed with the valved trocar cannulas.
Although the surgical platform used allowed control over both flow and IOP using its IOP compensation feature, there was still a decrease in IOP and fluid leakage when instruments were removed from one or more non-valved trocar cannulas. The valved trocar cannulas maintained the IOP at the surgeon-selected setting resulting in negligible fluid leakage during instrument exchange.
This PDF is available to Subscribers Only