Session Title: Vitreoretinal Surgery II
Session Date/Time: Friday 18/09/2015 | 08:00-10:00
Paper Time: 09:20
First Author: : A.Daruich SWITZERLAND
Co Author(s): : V. Varlet J. Pournaras T. Wolfensberger
PURPOSE:To report 11 cases of sticky silicone oil (SO) observed after the introduction of a new perfluorooctane (PFO) at our institution and to present 2 comparative chemical analyses between the new PFO and the PFO that had been used previously and between sticky silicone and normal oil samples retrieved from patients at oil removal.
We retrospectively analyzed the clinical features of 11 patients who presented with a sticky silicone phenomenon during 4 months after the introduction of a new PFO. The occurrence of sticky SO was based on the surgeon’s intraoperative observations. General clinical data, visual acuities (VA), slit-lamp and fundus examinations were reviewed and the indication and duration of SO tamponade as well as of postoperative complications were recorded. PFO of both suppliers, the new one (ala® octa from Ala medics, Dornstadt, Germany) and the previous one (FCI-octa® from FCI, Paris, France) were analyzed by gas chromatography coupled to mass spectrometry. Two samples of sticky SO and 2 samples of normal SO taken during oil removal were also analyzed by headspace gas chromatography coupled to tandem mass spectrometry.
Eleven patients presented the sticky SO phenomenon. The indication of SO tamponade was retinal detachment (RD) with proliferative vitreo-retinopathy (4 cases), RD with giant tear (4 cases), RD with acute retinal necrosis (1 case), recurrence of RD with scleromalacia (1 case), and tumorectomy of uveal melanoma (1 case). Mean duration of tamponade was 95± 49 days. The sticky silicone oil was adherent to the retinal surface (7 cases) or floating in the vitreous cavity (2 cases). In one of the cases where sticky silicone was adherent to the retina, a central scotoma was observed after complete removal of SO. Mean preoperative VA was 1.32 ± 1.35 LogMAR and mean postoperative VA was 1.08 ± 1.08 LogMAR (P=0.95). Gas chromatography analyses showed that the old PFO presented impurities such as perfluorodecalin (PFD) in its composition. The new PFO presented no impurity. SO samples removed from normal patients showed two well-delimitated phases, one aqueous and one lipid phase. These two phases were less defined in sticky SO samples. The amounts of PFO were similar in sticky and normal patients in the lipid phase. PFO was found in the aqueous phase in one of the two sticky samples, but not in normal ones.
Sticky SO was observed after the introduction of a new PFO, which showed a higher degree of purity compared to the previously used product, which contained PFD. Since the solubility of PFD in SO is much greater than that of PFO, the new PFO was retained within the aqueous phase, which may modify the behavior of SO and produce a sticky phenomenon. Slight impurities in the PFO may thus - albeit counterintuitively – be of long- term benefit.