Session Title: Vitreoretinal Surgery II
Session Date/Time: Friday 18/09/2015 | 08:00-10:00
Paper Time: 08:00
First Author: : S.PastorIdoate UNITED KINGDOM
Co Author(s): : R. Bonshek I. Luciane P. Bishop I. Zambrano A. Mironov P. Stanga
PURPOSE:The purpose of this study is to evaluate the effect of gauge size, percentage of ultrasound power (US) and aspiration settings on the structural components of the crystalline lens and retinal layers using a new prototype of ultrasonic harmonics vitrector (UHV). We compare our results using this new technology with those obtained with a currently commercially available pneumatic guillotine vitrector
The liquefaction and excision of the vitreous body using low power UHV is a promising new alternative to pneumatic guillotine vitrectomy systems.
Vitrectomy surgery (PPV) was performed using the UHV (Bausch + Lomb, St. Louis, MO, USA) and a currently commercially available pneumatic guillotine vitrector and 23G needles with both technologies (Stellaris PC® Vitrectomy system, Bausch + Lomb, St. Louis, MO, USA). Pre-determined aspiration levels (50, 100, 200, 300, 400, 500 and 600 mmHg) for both systems, cut rates for guillotine cutter (3000 and 5000 cuts per minute (CPM)) and percentages of US power for the UHV needles (10, 20, 30, 40, 50 %) were used in 14 consecutive cadaveric porcine eyes obtained within 12-24hs of slaughter. Six (6) closed PPV and eight (8) open-sky PPV (after removal of the anterior segment at the pars plana) were performed. The UHV and guillotine vitrector were held at 3 to 5 mm in front of the macula. The effects of US and guillotine technology were also tested in 4 cadaveric porcine crystalline lenses submerged in Balanced Salt Solution (BSS®) and by touching the posterior capsule with both the UHV and the guillotine vitrector. The crystalline lens and the retinal specimens were evaluated using microscopy and histochemical methods.
There were no macroscopic retinal defects associated with the use of neither the UHV nor the guillotine vitrectors at 10, 20, 30, 40, 50% US and 3000 and 5000 cut rates. Neither needle gauge nor wall thickness of the UHV affected the molecular structure of the retina layers. Disruption of the posterior capsule and structural lens defects were found after two min contact with guillotine vitrectors. However, just only, small disruptions of the posterior capsule or structural lens defects were found after two min contact with the UHV.
The retinal structure does not seem to be affected by gauge of the UHV needle for similar ports and vacuums. The use of an UHV in the middle of the vitreous cavity and at 3 to 5 mm from the retina and at the described US % of power may be safe. UHV is a promising new alternative to the currently commercially available guillotine-based technology for vitrectomy systems.