Chirurgische Therapie retinaler Venenverschlüsse

Abstract

Retinal vein occlusions are the second most common vision threatening retinal vascular disorders. Our therapeutic armamentarium for functional improvement was very limited in the past for all types of retinal vein occlusions (branch, central and hemi-central retinal vein occlusion). Also pathomechanism and risk factors are not completely understood yet. Argon-laser-photocoagulation can prevent the development and treat neovascularizations successfully, but is unable to improve visual function in most cases. Thrombolytic therapy applied systemically is limited due to serious side effects but may be helpful when injected intraocularly. Isovolemic hemodilution may be efficacious in central retinal vein occlusion (CRVO). The creation of a laser-induced chorioretinal venous anastomosis showed serious complications. Since 1999 numerous reports on successful surgical techniques were published. It could be shown that the dissection of the adventitial sheath with separation of the artery from the vein at the arteriovenous crossing where branch retinal vein occlusion occurs can re-establish the retinal blood flow with reduction of macular edema. But it is still unclear which step of the surgery (vitrectomy, ILM-peeling, sheathotomy) is causative for the results. A new surgical approach in CRVO is the radial optic neurotomy (RON). This technique was primarily performed under the hypothesis of decompression of the central vein by cutting the scleral ring. Meanwhile there is some evidence that the formation of chorioretinal shunts may be the decisive factor in cases of successfully performed RON. Due to inconsistent and rare data this surgical procedure needs further evaluation. Another surgical option is the cannulation of the occluded vein. This technique seems to be feasible but the clinical results still have to be proved. Despite several uncertainties and open questions, surgical techniques are likely to overcome the desolate therapeutic situation for retinal vein occlusion of the past.