Transhepatic or endoscopic placement of self-expanding metallic stents is an established method of palliative treatment for relieving malignant biliary obstructions. Metallic stents were found to be superior to plastic stents, and they have longer patency rates and lower complication rates [1–3]. The most frequent causes of stent occlusion are sludge formation, tumor ingrowth, proximal and distal tumor overgrowth, food debris, and stone formation [4,5]. Covered stents were developed to minimize …