[Liquid embolic agents--Onyx as problem solver].

CLINICAL/METHODICAL ISSUE: Liquid embolic agents are used for permanent occlusion of capillaries but optimal administration properties are lacking. STANDARD RADIOLOGICAL
METHODS: The lack of visualization by fluoroscopy and the risk of serious complications are disadvantages of conventional embolic agents, such as ethanol and Histoacryl. METHODICAL INNOVATIONS: Onyx is a liquid embolic agent consisting of ethylene vinyl alcohol copolymer dissolved in various concentrations of dimethyl sulfoxide (DMSO) and suspended micronized tantalum powder to provide contrast for fluoroscopy. PERFORMANCE: The physicochemical characteristics of Onyx allow controlled application, forming a defined cast and permanent occlusion. Disadvantages are the high costs. Furthermore, the solvent DMSO requires special catheter material and causes pain during Onyx application. ACHIEVEMENTS: Onyx has been primarily used for interventional neuroradiological treatment but peripheral applications are becoming increasingly more common. PRACTICAL RECOMMENDATIONS: Currently, Onyx is mainly used for embolotherapy of endoleaks after endovascular aortic aneurysm repair, for treatment of acute arterial bleeding and for treatment of arteriovenous malformations.