Indications and technical methods of endoscopic biliary stenting using the Doublelayer stent

Abstract

Endoscopic biliary drainage (EBD) includes endoscopic nasobiliary drainage (ENBD) and endoscopic biliary stenting (EBS). The stents used for EBS are either plastic (PS) or metallic (MS). Various kinds of PS and MS have been developed and are now being used. PS are inexpensive, exchangeable, and easy to insert, but can become occluded by clogging more quickly than MS. To prolong the duration of stent patency, the Doublelayer stent (DLS) was developed. The DLS has a three-layer structure. The inner layer is made of a perfluro alkoxy (PFA) material containing specially processed and chemically smoothened Teflon. The inner surface is quite smooth without being either concave or convex, which prevents the stent from becoming encrusted with biliary constituents or proteins. The outer layer is made of a polyamide elastomer, which provides the necessary strength. The outer layer is made of a polyamide elastomer, which provides the necessary strength. The duration of the patency of the prototype DLS with side holes was similar to that of an uncovered MS. Future development may result in a PS with a duration of patency comparable to that of the covered MS. Such a stent would offer greater efficiency and fewer complications. Improving the DLS may be the shortest path to this goal. © 2008 Springer Japan.