High-density silicone oil (Densiron) as a primary intraocular tamponade: 12-month follow up

Background The high-density silicone oil (Densiron 68), a mixture of F₆H₈ with silicone oil, seems to be a therapeutic option, at least in selected patients with complex inferior retinal re-detachment, where standard procedures have already failed. In an interventional case series we used Densiron as a primary endotamponade. Methods Twelve eyes of 12 patients aged 31 years to 85 years with inferior complex rhegmatogenous retinal detachment with secondary proliferative vitreoretinopathy (PVR) grades CP2 to CA8 were included. Surgical techniques (pars plana vitrectomy, membrane peeling, retinotomy, retinectomy, endophotocoagulation, cryocoagulation, endotamponade) did not include a scleral buckling procedure (except one eye). Mean duration of the Densiron endotamponade was 78.3  ±  29.74 days, with a mean follow up after removal of 400.6 ± 85.4 days. Results After Densiron removal, four patients (33.3%) showed a stable reattached retina without further interventions, while, in six patients (50%), recurrent retinal re-detachment appeared during endotamponade, generally within 2 months. One patient (8.3%) developed re-detachment 5 months after Densiron removal. One eye (8.3%) lost light perception due to severe intraretinal fibrosis with chronic hypotonia, despite complete retinal re-attachment. Visual acuity improved from mean logarithm of the minimum angle of resolution (logMAR) of 2.95 ± 1.21 to 1.87 ± 1.32 (statistically significant, P = 0.022). Side effects included temporary inflammatory reaction/fibrin accumulation (n = 2/2), moderate-to-severe intraretinal fibrosis (n = 3), elevated intraocular pressure (IOP) (n = 3), emulsification (n = 2), sterile hypopyon (n = 1), vitreous haemorrhage (n = 1) and chronic hypotony (n = 1). Conclusion Primary anatomical success rate of 33.3% was less encouraging than as expected. Especially, re-detachments within the posterior staphyloma in highly myopic patients were common during Densiron endotamponade. However, the surgical success increased to 75% after re-intervention, even without the use of an additional encircling band. The observed adverse effects and the functional outcomes do not contraindicate the use of Densiron as an internal tamponade for a period of 3 months.     

Different endotamponade agents and their clinical indications

The use of polydimethylsiloxane (PDMS) as silicone oil endotamponade has become a gold standard in retinal surgery. In cases of complicated retinal detachment with inferior and posterior retinal detachment this tamponade may be insufficient, and heavy silicone oils may be superior in such cases. Monocentric studies about use of the heavy silicone oil Densiron 68, a mixture of PDMS with perfluorohexyloctane (F6 H8), are reviewed. Meanwhile, F 6 H8 is approved as sole endotamponade, but complications such as emulsification and inflammation associated with the use of only F 6 H8 as endotamponade are reported and will also be reviewed. An advantage of heavy silicone oils is the relatively short residence time of the endotamponade. An uncomfortable "head down" position of the patients after surgery is not necessary. Current research focuses on developing new heavy silicone oils with a lower tendency to emulsify.     

Endothelial dysfunction in patients with rheumatoid arthritis is associated with a reduced number and impaired function of endothelial progenitor cells

BACKGROUND: Rheumatoid arthritis (RA) is associated with increased morbidity and mortality attributable to accelerated atherosclerosis and cardiovascular events. OBJECTIVE: To determine the role played by endothelial progenitor cells (EPC) in the defence system against arteriosclerosis. METHODS: The number and function of EPC in 13 young patients with RA with low disease activity (DAS28 3.5 (0.3)) and 13 healthy control subjects was studied. Endothelial function was investigated by agonist-induced, endothelium dependent vasodilatation measured by the forearm blood flow technique. Migratory activity and adhesion of EPC to tumour necrosis factor alpha (TNFalpha) activated mature endothelial cells and components of the extracellular matrix were tested in vitro. Putative precursor populations (CD34(+), CD34(+)/CD133(+), and CD34(+)/KDR(+) haematopoietic stem cells) were measured by flow cytometric analysis. RESULTS: Acetylcholine-induced, endothelium dependent vasodilatation was reduced by about 50% in patients with RA, indicating endothelial dysfunction, whereas endothelium-independent vasodilatation in response to glyceryl trinitrate was at control level. Significantly reduced numbers of EPC were found in the patients compared with controls. Migratory activity of EPC was decreased in patients with RA. Adhesion to mature endothelial cells after activation with TNFalpha was enhanced only in controls. The adhesion to matrix proteins and the number of putative precursor cell lineages was comparable in both groups. CONCLUSION: Endothelial dysfunction in patients with RA with low grade inflammation is associated with a reduced number and partial dysfunction of EPC. Further studies are needed to explore whether interventions that potentially ameliorate the number and function of EPC also improve endothelial function in these patients.