[Biliary stents]

Endoscopically implantable stents are today the mainstay for therapy of biliary stenoses. It is important to know if a benign or a malignant stenosis is the cause of the biliary obstruction. Generally benign stenoses are treated with plastic-stents whereas malignant stenoses are managed by implantation of a metallic stent. The main indications for plastic stents are postoperative strictures in the biliary tree for example, after biliary tract surgery or liver transplantation, primary sclerosing cholangitis and postoperative biliary leakage. Metallic stents are implanted in palliative circumstances like in stenosing cholangiocarcinoma or in situations where a hepatic metastasis exerts an extrinsic compression on the biliary tract with consecutive cholestasis. The materials used for manufacturing both stent types are biologically inert and thus biocompatible. A current poorly resolved problem is the occlusion of the stent lumen (by sludge, bacterial degradation products etc.) which occurs in both stent types with time. These problems lead to stentocclusion around three to six months after implantation and necessitate endoscopical re-interventions in order to overcome the occlusion. The patency rate for metallic stents is better than for plastic ones. The endoscopic stenttherapy is equivalent to surgical therapy (Intestinal bypass-procedures).