while embodiments of the present disclosure may take many forms , there are described in detail herein specific embodiments of the present disclosure . this description is an exemplification of the principles of the present disclosure and is not intended to limit the disclosure to the particular embodiments illustrated . the following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same . the drawings , which are not necessarily to scale , depict illustrative embodiments and are not intended to limit the scope of the disclosure . those skilled in the art will recognize that the dimensions and materials discussed herein are merely exemplary and are not intended to limit the scope of the present disclosure . in some embodiments , the present disclosure relates generally to a stent having a bulge or enlarged middle portion where the bulge is designed to adapt to the antrum pouch created during sleeve gastrectomy or biliopancreatic diversion with duodenal switch ( sg ) surgery . the role of the bulge is to prevent downwards and / or upwards stent migration and close / insulate any leaks that may occur . the present disclosure is discussed in more detail with respect to the figures below . in some embodiments , the stent includes a sleeve that extends past the distal end of the stent into the duodenum and past the common bile duct to prevent reflux . turning now to the figures , fig5 is a partial side view of one embodiment of a stent according to the disclosure . stent 20 includes a flared proximal end portion 22 , an enlarged middle portion 24 and a distal end portion 26 connected to a polymeric sleeve 28 . sleeve 28 is partially illustrated in fig5 . while the enlarged middle portion 24 is shown in fig5 as having a symmetrical ovular shape , the shape may also be non - symmetrical as well . this stent is designed to pass from the esophagus , through the stomach , and into the duodenum . sleeve 28 extends distally past the distal end of the distal end portion 26 of the stent 20 and past the common bile duct . sleeve 28 is suitably formed of a material that allows it to collapse upon itself . this , in combination with the extension of the sleeve 28 beyond the common bile duct , allows the bile to fun down the outside of the sleeve and continue into the small intestine rather than splashing back into the stomach . sleeve 28 is suitably formed of a polymer material , and can also be formed of an elastomeric polymeric material . examples of elastomeric polymers include , but are not limited to , silicone , polyurethane and polyether - block - amide to mention only a few . fig6 is a side view of a stent 20 similar to that shown in fig5 , with the relative length of sleeve 28 to stent 20 . fig7 illustrates a stent 20 similar to those shown in fig5 and 6 wherein stent 20 is illustrated passing from the esophagus , through the stomach and into the duodenum . the sleeve 28 of stent 20 extends distally past the distal end or the distal end portion 26 past the common bile duct into the duodenum . proximal end portion 22 of stent 20 is in the esophagus , the enlarged middle portion 24 is located in the antrum of stomach and distal end portion 26 along with sleeve 28 is located in the duodenum . fig8 is a side view of an alternative embodiment of a stent 20 wherein the distal end portion 26 of stent 20 is relatively short , or just slightly greater than 0 mm and ends almost at the distal end of the enlarged central portion 24 of stent 20 . in this embodiment , the stent / sleeve is configured such that the sleeve 28 of the stent terminates in the stomach rather extending into the duodenum as illustrated in the embodiment shown in fig7 . again , as in the embodiment shown in fig7 above , sleeve 20 extends beyond the common bile duct . again , sleeve 20 is configured to collapse and close upon itself to prevent bile reflux . in this embodiment , however , the pyloric valve is still able to close to further aid in the prevention of bile reflux . fig9 illustrates stent similar to that shown in fig8 wherein stent 20 is shown passing from the esophagus , through the stomach , and ending in the pylorus . the enlarged central portion and the distal end 26 thereof , thus terminates in the stomach . the sleeve 28 of stent 20 passes through the pylorus 16 of the stomach and into the duodenum 5 . in this embodiment , only the sleeve 28 is located in the duodenum . fig1 is a side view of an alternative embodiment of a stent 20 wherein the sleeve 28 is eliminated . in this embodiment a valve 30 is positioned in the distal end portion 26 of the stent between the enlarged central portion 24 and the distal end of stent 20 . in some embodiments , the one - way flow valve may comprise one cuspid or multiple cuspids . in one embodiment , the stent includes a tricuspid one - way valve as shown in fig1 . positioning of a one way valve in the distal end portion 26 of stent 20 aids in the prevention or significant reduction of bile reflux . the valve 30 is positioned within the distal end portion 26 of stent so as to reside at approximately the same location as the pyloric sphincter . in some embodiments , stent 20 is in the formed of a braided or woven structure . valve 30 may be coupled to the braided or woven construction . fig1 and 13 illustrate alternative embodiments wherein at least a portion of the distal end portion 26 which will be disposed in the pyloric sphincter comprises a collapsible stent portion . the collapsible portion can be created in a variety of ways such as by reducing the radial strength of the stent in at least a portion of the end portion 26 or the entire portion , or by placing a collapsible sleeve or band around at least a portion of the distal end portion 26 . fig1 is a side view illustrating an alternative embodiment of a stent 20 wherein the valve 30 has been replaced with an elastomeric band 32 . band 32 may be formed of any suitable elastomeric material . examples include , but are not limited to , silicone , polyurethane and poly - ether - block amide . elastomeric band 32 is located in the distal end portion at the distal end of the enlarged middle portion 24 of stent 20 . elastomeric band 32 applies an inward pressure such that stent 20 closes upon itself in the region of elastomeric band 32 . when the stomach muscles contract , the bolus of food will be pushed out of the stomach bulge , past the elastomeric band , and into the duodenum . this causes the elastomeric band to expand . once the bolus of food has passed , the elastomeric band returns to it &# 39 ; s at rest state wherein the stent 20 in the region of elastomeric band 32 is again closed , preventing or significantly reducing bile reflux . the distal end portion 26 of stent 20 can be formed of a braided or woven construction as the rest of stent 20 , but can be suitably formed of a continuous wall construction in this embodiment , as opposed to a braided or woven configuration . fig1 is an alternative embodiment wherein the distal end portion 26 of stent 20 extends through the pyloric sphincter . at this location , the radial force of stent 20 is lower than the enlarged middle portion 24 of stent 20 and the proximal end portion 22 of stent 20 to allow closure of the sphincter . the radial force can be reduced in a variety of different was such as reducing the wire diameter , lowering the braid angle , reducing the number of wires , etc . fig1 illustrates a reduction in braid angle in the distal end portion 26 of stent 20 . the radial force may also be reduced only on a segment of the distal end portion 26 of stent 20 such as that portion closest to the enlarged middle portion 24 of stent 20 . in any of the embodiments disclosed above , stent 20 may be formed from any suitable stent material . examples include , but are not limited to , nickel - titanium alloy ( nitinol ), cobalt - chromium - nickel alloy ( elgiloy ), cobalt - chromium alloy , or stainless steel . in any of the embodiments disclosed above , the entirety of the stent , or any portions thereof , may be formed of a braided or woven construction . in any of the embodiments disclosed above , the stent , or any portions thereof , may be a laser cut stent . in any of the embodiments disclosed above , the entirety of stent 20 may include any appropriate cover , or any portion or portions thereof . the covering may be formed of any suitable material . examples include , but are not limited to , polyesters , polypropylenes , polyethylenes , polyurethanes , polynaphthalenes , polytetrafluoroethylenes , expanded polytetrafluoroethylene , silicone , copolymers thereof and mixtures or combinations thereof . in some implementations , the polymeric cover is silicone . a description of some embodiments of a stent delivery catheter , stylet for use therein and methods of using the same is contained in one or more of the following statements :
an endoscopic stent for implantation in a patient after sleeve gastrectomy or biliopancreatic diversion with duodenal switch or biliopancreatic diversion with duodenal switch comprising a stent portion , the stent portion comprising a proximal end portion , the proximal end portion defined by a length of about 50 mm to about 200 mm , an enlarged middle portion , a middle portion having an enlarged diameter relative to the proximal end portion and the distal end portion and defined by a length of about 20 mm to about 80 mm , and a distal end portion and a polymeric sleeve portion engaged to and extending distally from the distal end portion of the stent .