Abstract
Purpose: :
To describe a new technique for the removal of Densiron 68 (Fluoron GmbH, Germany) via pars plana with a 23G sutureless transconjunctival system without aspiration.
Methods: :
After the introduction of three 23G cannulas via pars plana, a syringe with 10 ml of perfluorodecalin (DK-line, Opsia, France) is connected to the infusion line of the vitrectomy system (Constellation, Alcon Laboratories, USA). The surgeon administers a controlled, 4 psi continuous injection of perfluorodecalin wich easily pushes the Densiron-68 out from the other two open cannulas by the positive pressure induced and by the difference of specific gravity of the two fluids. After the exchange, the syringe with perfluorodecalin is removed, and the cannula is connected to the BSS infusion line.
Results: :
The Densiron 68 is safely and completely removed by the heavier perfluorodecalin without any active suction, despite the small diameter of the 23 Gauge cannulas, according to the Poiseuille’s law. Remaining little bubbles of Densiron-68 floating on surface of the perfluorodecalin can be removed with moderate aspiration. The perfluorodecalin in the vitreous chamber allows the peeling of the eventual epiretinal membranes or the endophotocoagulation, and can be exchanged with BSS or gas at the end of the surgery.
Conclusions: :
Many Authors have described the heavy silicone oil tamponade removal by active suction, in both 20 or 23 gauge, or in a mixed system. In all cases it is necessary to have a very high negative pressure. When using of short cannulas in a 23 gauge system the tubeless siphon effect described must not be interrupted by the bubble breaking off and falling away from the cannula. A negative pressure of 600 mmHg during the suction of heavy tamponade removal may be risky in cases of poor vision due to any transparency loss of the Anterior Segment of the eye. With our technique, the low positive pressure induced by the perfluorodecalin controlled infusion may reduce the risk of surgical trauma and prepare the eye for a potential peeling of the epiretinal membrane or endophotocoagulation.
Keywords: vitreous substitutes • vitreoretinal surgery • retinal detachment