Development of the lumen-apposing metal stent (LAMS)

Whether plastic or metal, tubular stents designed to relieve lumenal obstruction have significant limitations when applied to translumenal applications. Importantly, they do not impart lumen-to-lumen apposition, which may result in perforation and leakage of contents if there is physical separation of the lumens. In addition, the tubular configuration exceeds the anatomical requirement of a translumenal anastomosis and the exposed stent ends jutting into the lumens may cause tissue trauma with resultant perforation and bleeding. The longer stent length is also more prone to clogging. The shortcomings of tubular stents when applied “off label” for EUS-guided transluminal applications inspired the author to develop the LAMS. The LAMS concept is summarized in the patent abstract: “The present invention relates to a device for endoscopy or endosonography-guided transluminal interventions whereby two luminal structures in the body may be drawn toward each other and a fluid conduit formed in between.” Various LAMS prototypes were built and tested using benchtop simulators of non-adherent lumens. A single operator delivery platform, already familiar to endosonographers performing FNA, was developed to enable single-operator, single-hand control for the LAMS delivery. The “hot” electrocautery-enhanced delivery system was developed to enable the operator to access the target lumen with a stent-loaded delivery catheter followed by immediate deployment of the stent (non-Seldinger technique). The passage of an endoscope through the LAMS enables the endoscopist to expand the frontier of endoscopic intervention to virtually any luminal structure outside of the gastrointestinal tract.