[Percutaneous metallic biliary prosthesis]

Two types of metallic endoprostheses may be placed via a transhepatic approach: 1) self expandable stents which open by themselves as soon as they are released from the carrier system, 2) balloon expandable stents which need to be dilated by a balloon catheter at the time of deployment. Gianturco and Wallstent endoprostheses belong to the first group and are most often used. The fenestrated wall of metallic endoprostheses preserves the patency of bile ducts joining the stented segment, which is a major advantage for hilar and intra-hepatic stenosis. Their design allows the endoprostheses to be incorporated into the bile duct wall, minimising biliary encrustation and leaving a wider internal lumen as compared to plastic stents. On the other hand, tumor ingrowth in the stented segment is possible and parietal incorporation makes the stent nonretrievable after a few weeks. A favorable indication is therefore extrinsic compression, especially in hilar and intra-hepatic segments. Whatever the indications, metallic stenting has an advantage in the treatment of biliary stenosis, either benign or malignant, owing to less traumatic positioning while their patency rate remains high.