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Dina Joy K Abulon, Martin Charles; Comparison of Peripheral Vitreous Incarceration using Valved and Non-Valved Cannula. Invest. Ophthalmol. Vis. Sci. 2014;55(13):2349.
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© ARVO (1962-2015); The Authors (2016-present)
Sclerotomy for vitrectomy surgery has evolved from large gauge surgical techniques requiring sutures to sutureless incisions using microcannula. These microincisional trocar cannula designs were less invasive and demonstrated improved patient comfort. A new valved design allowed surgeons to maintain intraoperative IOP better than non-valved designs. A previous study evaluated vitreous incarceration with 23-gauge valved and non-valved cannulas. The purpose of this study is to expand upon previous data and compare peripheral vitreous incarceration after pars plana incisions using 27-, 25-, and 23-gauge valved and non-valved cannula.
A total of twelve cadaveric porcine eyes were tested. Edgeplus® 27-, 25-, and 23-gauge valved entry systems (Alcon Labs, CA, US) were compared to Edgeplus® non-valved entry systems of equivalent gauge size. In each eye, two adjacent incisions were created 2.5mm apart: one incision housed the valved cannula and the adjacent incision housed the non-valved cannula. Triamcinalone was injected through the sclera between the valved and non-valved cannula. A 1.9mm diameter rod lens boroscope (Karl Storz, Tuttlingen, Germany) was inserted through a 1.9mm incision in the posterior segment, opposite from the two trocar cannula incisions. Endoscopic video captured the presence of incarcerated vitreous into the inner lumen of the trocar cannulas. Using ImageJ software (NIH, Maryland, US), the amount of vitreous incarcerated into the cannula was quantified and reported as a percentage of the analyzed area.
On average, the 27-gauge non-valved cannulas showed 30% incarcerated vitreous around the inner lumen of the cannula while valved 27-ga cannulas showed 0% incarcerated vitreous. The 25-gauge non-valved cannulas showed 46% incarceration compared to 1% incarceration with valved cannulas. With 23-gauge non-valved cannulas, incarceration was 30% compared to 0% with valved cannulas.
The 27-, 25-, and 23-gauge non-valved cannulas all generated more vitreous incarceration through the trocar cannula than the corresponding valved cannulas. Election of valved cannulas may improve surgical outcomes.
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