Migration-resistant devices, systems, and methods, and methods of implantation thereof

Abstract

An implantable device configured to be placed at a placement site such that it traverses a passageway within a body, the implantable device having features that increase resistance of at least a portion of the implantable device to migration from the placement site. The implantable device may have a surface that contacts tissue at the placement site configured to promote tissue ingrowth into the implantable device. Surfaces of the implantable device that do not contact tissue may be enlarged and coated with a coating material to increase the strength of the coated portion of the implantable device to resist migration relative to the placement site of the implantable device.

Description

[Technical field]

[0001] The present disclosure relates generally to the field of implantable devices, systems, and methods, and more particularly, to the field of devices, systems, and methods for resisting migration of an implantable device from an anatomical passageway in which the device is placed. [Background technology]

[0002] Various medical procedures involve obstructing the flow of material through a body passageway. For example, methods of treating various medical conditions, such as obesity, diabetes, or duodenal ulcers, involve bypassing or restricting the flow of material through the duodenum. Common bariatric procedures include sleeve gastrectomy, Roux-en-Y gastric bypass, and gastric banding, and are either obstructive (as in gastric banding and sleeve gastrectomy), anti-resorptive (as in Roux-en-Y), or both. All of these procedures are highly invasive and can be associated with serious complications. Newer, less invasive procedures, which involve less trauma and a lower risk of complications, include the creation of an anastomosis, such as between the stomach and jejunum (gastrojejunostomy, or GJ for short), and the creation of a pylorus atresia by endoscopic procedures (e.g., endoscopic ultrasound, or EUS for short), such as the NOTES (natural orifice transluminal endoscopic surgery) procedure. If the treatment requires a complete bypass of the duodenum, implantation into the pylorus (e.g., full implantation) may be recommended. An implantable device, such as a duodenal expulsion device, may be placed in the pyloric sphincter to prevent or block the passage of material (fluid, chyme, etc.) from the stomach through the pylorus to the duodenum. Various challenges to preventing migration of a placed implantable device include the natural movement of the body (e.g., digestive system) and the continuous flow of material to the implantable device. The peristaltic movement of the pylorus to pass material through the pylorus (e.g., distally toward the small intestine), the usually less frequent reverse peristalsis through the pylorus (proximally toward the stomach), and the natural tendency of the pylorus to expel material within the pylorus present unique challenges to the placement and retention of a pyloric implantable device. Back pressure from the large and small intestines through the duodenum may also cause device migration. Thus, improved structures and methods for increasing the resistance to migration of an implantable device are desired. Summary of the Invention

[0003] This summary of the disclosure is provided to aid in understanding, and those skilled in the art will appreciate that each of the various aspects and features of the disclosure may be advantageously used separately in some cases, or in other cases in combination with other aspects and features of the disclosure. No limitations on the scope of the claimed subject matter, either by inclusion or non-inclusion of elements, components, etc., are intended in this summary.

[0004] In accordance with various principles of the present disclosure, an implantable device extending along a longitudinal axis and having a first end, a second end, and an intermediate region between the first end and the second end includes a saddle along the intermediate region, a first retention member extending radially outward from the longitudinal axis along the first end, and a second retention member extending radially outward from the longitudinal axis along the second end, wherein at least a portion of a surface of the saddle and at least a portion of the inwardly facing surfaces of the first retention member and the second retention member facing toward the saddle are configured to promote tissue ingrowth, and the outwardly facing sides of the first retention member and the second retention member facing away from the saddle have a surface area large enough that a coating material provided on the sides increases the pull-out strength of the first retention member and the second retention member.

[0005] In some embodiments, the outwardly facing side of at least one of the first retaining member or the second retaining member is about 500 mm 2 has a surface area greater than In some embodiments, the lip extends axially from the second retention member a distance greater than the distance between the inwardly facing and outwardly facing sides of the second retention member and is configured to promote tissue growth within the lip.

[0006] In some embodiments, the first retaining member and the second retaining member are each double-walled retaining members having an inner wall along an inwardly facing side and an outer wall along an outwardly facing side, and the distance between the inner wall and the outer wall of the second retaining member is greater than the distance between the inner wall and the outer wall of the first retaining member.

[0007] In some embodiments, the implantable device further includes a lip extending axially from at least one of the first retention member or the second retention member in a direction away from the saddle, hi some embodiments, the lip is coated with a coating material that reduces the flexibility of the lip.

[0008] In some embodiments, the first retention member and the second retention member are of different sizes, shapes, configurations, and / or dimensions. In some embodiments, the saddle is configured to be placed through the pylorus, the first retention member is configured to seat in a portion of the stomach surrounding the pylorus, and the second retention member is configured to extend into the duodenum extending from the pylorus, hi some embodiments, the saddle is narrowed to occlude the flow of material through the pylorus.

[0009] In some embodiments, the diameter of the first retention member is greater than the diameter of the second retention member. In some embodiments, the saddle and the inwardly facing sides of the first and second retention members facing toward the saddle have walls with gaps formed therein and are left uncoated to promote tissue ingrowth into the gaps.

[0010] In accordance with various principles of the present disclosure, the implantable device is formed from a tubular element having a first end, a second end, an intermediate region between the first end and the second end, and a lumen formed therethrough. In some embodiments, the implantable device includes a saddle along an intermediate region, a first retention member formed by a portion of the tubular element along a first end of the tubular element, the first retention member having a first diameter greater than an outer diameter of the saddle to form an inner wall of the first retention member facing toward the saddle and an outer wall of the first retention member facing away from the saddle, and a second retention member formed by a portion of the tubular element along a second end of the tubular element, the second retention member having a second diameter greater than the outer diameter of the saddle to form an inner wall of the second retention member facing toward the saddle and an outer wall of the second retention member facing away from the saddle, wherein the first free end of the tubular element has a diameter sufficiently smaller than the outer diameter of the first retention member to provide a sufficient surface area to receive a coating material to increase the stiffness of the outer wall of the first retention member.

[0011] In some embodiments, a diameter of at least one of the first free end of the tubular element and the second free end of the tubular element is less than a maximum diameter of the saddle portion. In some embodiments, the retention members have different sizes, shapes, configurations, and / or dimensions.

[0012] In some embodiments, the outer diameter of the first retention member is greater than the outer diameter of the second retention member. In some embodiments, the distance between the inner wall of the second retaining member and the outer wall of the second retaining member is greater than the distance between the inner wall of the first retaining member and the outer wall of the first retaining member.

[0013] In some embodiments, the implantable device includes a lip extending axially from the second retention member in a direction away from the saddle, the lip having a length greater than a distance between an inner wall of the second retention member and an outer wall of the second retention member, hi some embodiments, the outer wall of the second retention member is coated, such that the outer surface of the lip is configured to promote tissue ingrowth.

[0014] In accordance with various principles of the present disclosure, a method of forming an implantable device from a tubular element having a first end, a second end, an intermediate region between the first and second ends, and a lumen formed therethrough includes narrowing the intermediate region of the tubular element to form a saddle along the intermediate region; increasing a diameter of the tubular element along the first end of the tubular element to be greater than an outer diameter of the saddle to form an inner wall of the first retaining member facing the saddle and an outer wall of the first retaining member facing away from the saddle; and drawing a first free end of the tubular element inwardly to have a diameter sufficiently smaller than the outer diameter of the first retaining member to provide a surface area sufficient to accept a coating material to increase the stiffness of the outer wall of the first retaining member.

[0015] In some embodiments, the first free end of the tubular element is retracted inwardly to have a diameter smaller than the maximum diameter of the saddle portion. In some embodiments, the retention members are formed to have different sizes, shapes, configurations, and / or dimensions.

[0016] In some embodiments, the diameter of a portion of the tubular element along the first end of the tubular element is increased such that the outer diameter of the first retaining member is greater than the outer diameter of the second retaining member. In some embodiments, the inner wall of the second retaining member and the outer wall of the second retaining member are formed to be greater than the distance between the inner wall of the first retaining member and the outer wall of the first retaining member.

[0017] In some embodiments, a lip is formed extending axially from the second retaining member in a direction away from the saddle portion, the lip having a length greater than the distance between an inner wall of the second retaining member and an outer wall of the second retaining member.

[0018] In some embodiments, an outer wall of the second retention member is coated and the outer surface of the lip is configured to promote tissue ingrowth. In accordance with various principles of the present disclosure, a method of placing an implantable device at a placement site includes performing endoscopic mucosal resection of a portion of tissue at the placement site to promote tissue ingrowth at the resected tissue site, and placing an implantable device having a surface in contact with the resected tissue site, the implantable device configured to allow tissue ingrowth thereat.

[0019] In some embodiments, the method includes ablating tissue at the placement site surrounding the resected tissue using mucosal abrasion.

[0020] In some embodiments, the first retention member has an outer diameter larger than the outer diameter of the second retention member and has an inwardly facing side configured to contact tissue surrounding the entrance and promote tissue ingrowth therein, and an outwardly facing side facing away from the body passage and not contacting tissue and coated with a material that increases its pull-out strength, wherein the outer diameter of the first retention member and the material coated on the first retention member increase the retention strength of the first retention member against movement of the implantable device into the body passage.

[0021] These and other features and advantages of the present disclosure will become readily apparent from the following detailed description, and the scope of the claimed invention will be set forth in the appended claims. Although the following disclosure is presented in terms of aspects or embodiments, it should be recognized that each aspect may be claimed separately or in combination with aspects and features of that embodiment or any other embodiment. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a perspective view illustrating one embodiment of an implantable device formed in accordance with various aspects of the present disclosure and positioned in a schematic representation of a gastrointestinal environment. [Diagram 2] FIG. 2 is a front view of an implantable device formed as in FIG. 1. [Diagram 3] FIG. 3 is a perspective view of an implantable device formed as in FIG. 2. [Figure 4] 1 is a front view of another example embodiment of an implantable device formed in accordance with various principles of the present disclosure. [Diagram 5] FIG. 5 is a perspective view of an implantable device formed as in FIG. 4. [Figure 6] 1 is a front view of another example embodiment of an implantable device formed in accordance with various principles of the present disclosure. [Figure 7] FIG. 7 is a perspective view of an implantable device formed as in FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Non-limiting embodiments of the present disclosure are described by way of example with reference to the accompanying drawings, which are schematic and not intended to be to scale. The accompanying drawings are provided for illustrative purposes only, and the dimensions, positions, order, and relative sizes reflected in each of the drawings may vary. For example, the devices may be enlarged so that details can be appreciated, but are intended to be scaled in relation to fitting, for example, into a delivery catheter or working channel of an endoscope. In each of the drawings, identical or nearly identical or equivalent elements are generally represented by the same reference numerals, and similar elements shown are generally designated by different similar reference numerals incremented by 100, and redundant descriptions are omitted. For the sake of clarity and conciseness, not every element is labeled in every drawing, nor every element of every embodiment is shown, unless explanation is necessary to enable a person skilled in the art to understand the present disclosure.

[0024] The detailed description is better understood in conjunction with the accompanying drawings, in which like reference numerals represent like elements and in which: The following detailed description should be read with reference to the drawings showing exemplary embodiments. It should be understood that the disclosure is not limited to the specific embodiments described and may therefore vary. All devices and systems as well as methods described herein are examples of devices and / or systems and / or methods implemented according to one or more principles of the disclosure. Each example of an embodiment is provided for illustration and is merely an example, not the only way to implement these principles. Thus, references to elements or structures or features in the drawings should be recognized as references to example embodiments of the disclosure and should not be understood as limiting the disclosure to the particular elements, structures or features shown. Other examples of ways of implementing the disclosed principles will occur to those skilled in the art upon reading this disclosure. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the present subject matter. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still further embodiments. It is therefore intended that the present subject matter encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0025] It will be understood that the present disclosure is described in this application with varying degrees of detail. In certain instances, details that are not necessary for a person skilled in the art to understand the present disclosure or that make it difficult for the person skilled in the art to appreciate other details may be omitted. The terms used herein are only for the purpose of describing certain embodiments and are not intended to be limiting beyond the scope of the appended claims. Unless otherwise defined, technical terms used herein should be understood as commonly understood by those skilled in the art to which the present disclosure belongs. All of the devices and / or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure.

[0026] As used herein, "proximal" refers to a direction or location closest to a user (healthcare professional or clinician or technician or operator or physician, etc. (these terms are used interchangeably herein without any limitation and include automated controller systems, etc.)) and / or closest to a delivery device when the device is used, etc. (e.g., when the device is introduced into a patient or during implantation, placement, or delivery), and "distal" refers to a direction or location furthest from a user and / or closest to a delivery device when the device is used, etc. (e.g., when the device is introduced into a patient or during implantation, placement, or delivery), and "Longitudinal" means extending along the longer or greater dimension of an element. "Center" means at least approximately bisecting through a center point and / or approximately equidistant from a perimeter or boundary, and "central axis" means, with respect to an opening, a line at least approximately bisecting through a center point of the opening and extending longitudinally along the length of the opening, where the opening comprises, for example, a tubular element, channel, cavity, or bore. As used herein, a "free end" of an element is an end beyond which such element does not extend.

[0027] In accordance with various principles of the present disclosure, the implantable device is sized, shaped, configured, and / or dimensioned to resist migration from the site at which the implantable device is placed. Such site is referred to herein for convenience and without any limitation as a placement site, and as used herein, is the site or location at which the device is placed, positioned, implanted, expanded, attached, etc. (such terms are used interchangeably herein, without any limitation), and may also be the intended treatment site or treatment location of the device when placed and used. The placement site may be a passageway or lumen in the body, and such terms are used interchangeably herein, without any limitation, and the broad principles of the present disclosure are applicable to various shapes and sizes of passageways, lumens, cavities, etc., or other anatomical structures in the body. The passageway in the body may extend between anatomical structures (e.g., body cavities or organs adjacent to the passageway in the body) that generally have a larger diameter than the passageway in the body.

[0028] An implantable device formed according to various principles of the present disclosure may be placed with the saddle region of the device extending across, through, or into a body passageway or body tissue (such terms are used interchangeably herein, without any limitation intended). It should be understood that body passageways herein include passageways formed through tissue by a medical procedure (i.e., not naturally occurring body passageways), such as passageways formed through opposing tissue walls (e.g., to form an anastomosis between the walls, or simply to hold the walls opposed). The body passageway may have an entrance and an exit, and the implantable device may include a retention member (which may alternatively be referred to as a flange) configured to engage one or more anatomical structures at the placement site to inhibit migration of the implantable device relative to the placement site. In some embodiments, the outer wall of the retention member may seat against an anatomical structure (e.g., body wall), such as along or adjacent to the entrance and / or exit of the body passageway in which the implantable device is placed, as an anti-migration structure configured to resist migration of the implantable device relative to the placement site (e.g., relative to the body passageway). It is understood that terms such as resist, hinder, prevent (and other grammatical forms) may be used interchangeably herein without any limitation. The retention member may extend radially outward along either end of the mid-region of the implantable device (where the saddle is located). It is understood that terms such as along, at, on, or adjacent to the end may be used interchangeably herein without any limitation, unless otherwise stated, and are intended to indicate a general relative spatial relationship, not a strictly defined location. For example, the retention member may be in the form of a lateral extension or flange that is wider than the mid-region of the device and wider than the body passageway in which the mid-region of the device is located. The retention member is generally wider (radially across the longitudinal axis of the body passageway) than the saddle and configured to seat against an internal body wall that extends radially outward from the body passageway.

[0029] In some embodiments, at least one of the retention members is configured to resist movement of the implantable device relative to the placement site. In some embodiments, the first retention member and the second retention member are similarly shaped, although such shapes may not have identical dimensions (i.e., the shapes may have different relative dimensions, scales, or proportions). For example, the first retention member and the second retention member may be substantial replicas of one another (optionally with different relative proportions) oriented in generally the same direction. Alternatively, in some embodiments, the first retention member and the second retention member may be mirror images (bilaterally symmetrical) (e.g., similar shapes oriented in generally opposite directions, optionally with different relative proportions). In some embodiments, the first retention member and the second retention member are generally not identical or symmetrical. For example, the first retention member and the second retention member may have different shapes, dimensions, relative proportions, etc. The outer diameter of at least one of the retention members may be increased to be significantly (e.g., about 10 times, or about 15 times, or about 17 times, or even about 20 times, including all increments therebetween) larger than the outer diameter of the saddle to increase retention strength and prevent migration of the implantable device relative to the placement site. In some embodiments, the implantable device may have an enlarged stomach retention member (e.g., having a larger diameter than the duodenal retention member) configured to be placed across the pylorus and to resist distal migration from the stomach into the duodenum. For example, the duodenal retention member may have an outer diameter of about 25-34 mm (generally limited by the average internal diameter of the duodenum), while the stomach retention member may have more room to expand within the stomach and may have a diameter greater than 30 mm, such as about 35 mm or about 40 mm or about 50 mm or about 60 mm, and potentially larger diameters (such dimensions including about 1 mm increments therebetween). The length of the device placed across the pylorus may be at least about 2 mm or about 3 mm, and may be about 12.5 mm, or even about 20 mm (e.g., if configured to extend across the duodenal bulb), or even about 50 mm (e.g., if configured to extend across the length of the duodenal portion of the small intestine).Additionally or alternatively, a device placed across the pylorus may have a duodenal retention member that extends into the duodenum and is elongated (along the longitudinal axis of the device) to provide additional surface area for tissue ingrowth into the duodenal retention member. In some embodiments, the size, shape, configuration, and / or dimensions of at least one of the retention members is altered to increase resistance by the retention member to migration.

[0030] In accordance with various principles of the present disclosure, one or both of the retention members are double-walled retention members with two walls adjacent and in contact or spaced apart from one another, each wall forming a side of the retention member. For convenience, and without any intention of limitation, the wall of each double-walled retention member closer to the saddle may be referred to herein as the inner or interior wall of the retention member, and the wall of each double-walled retention member further from the saddle may be referred to herein as the outer or exterior wall of the retention member. Various aspects of the inner and outer walls of a double-walled retention member formed in accordance with various principles of the present disclosure may be modified as described herein to enhance the ability of the retention member to hold an implantable device in place at the deployment site.

[0031] In some aspects, the implantable device is configured to promote tissue ingrowth against portions of the implantable device such that the implantable device resists migration relative to such tissue. In some embodiments, regions of the retention member are configured to promote tissue ingrowth against such regions of the implantable device. For example, regions of the retention member may be left as uncoated regions (not treated with substances that inhibit tissue ingrowth). It should be understood that terms such as region, surface, area, portion, segment, section, etc. may be referred to interchangeably herein without intending to be limiting. The uncoated regions of the implantable device generally include tissue-contacting surfaces of the implantable device. For example, at least a portion of the middle region of the device that extends through a passageway in the body and / or at least a portion of the inwardly facing (facing toward the middle region) surface of the retention member on the device (these regions or surfaces generally contact tissue at the placement site) are at least partially uncoated. In some embodiments, most or all of the tissue-contacting surfaces of the implantable device are uncoated, thereby allowing and even encouraging tissue ingrowth (e.g., by the structure or configuration of the walls of the implantable device, as described in more detail below) and inhibiting or preventing migration of the implantable device relative to the placement site.

[0032] It should be understood that various coatings may be applied to the implantable device for various purposes. The coating may be lubricious, to facilitate movement relative to the anatomy of the patient in which the device is implanted, and / or to facilitate the passage of materials (e.g., fluids, particles, tools, instruments, devices, etc.), and / or to prevent tissue ingrowth into the implantable device (e.g., by preventing tissue from wrapping around components or elements of the device and / or by filling spaces within the device, thereby preventing tissue from penetrating such spaces). The coating may also be provided to occlude the flow of materials through the coating or through the structure to which the coating is applied. Additionally or alternatively, the coating may also provide a degree of structural rigidity to a more flexible device. The coating may also be used to soften relatively sharp areas or structures of the implantable device. For example, the coating may be used on angular corners of the device or on the free ends of elements such as filaments of woven material (e.g., to protect the welded ends of woven or braided filaments). It should be understood that, as used herein, the terms filament, strand, wire, fiber, strut, and the like may be referred to interchangeably and are not intended to be limiting.

[0033] In accordance with various further principles of the present disclosure, a coating is applied to at least a portion of the retention member that does not contact tissue at the deployment site. The coating may increase the pull-out strength of the retention member. It should be understood that reference to increasing the pull-out strength may be understood to encompass increasing the retention strength, stiffness, resistance to migration (e.g., anti-migration properties), etc. of the flexible retention member. Coatings such as biocompatible polymeric materials may also be applied to the ends of the implantable device, such as to coat the welded ends of filaments (e.g., wires) that are braided or woven to form the implantable device.

[0034] In accordance with various principles of the present disclosure, to enhance the effect of the coating material on the pullout strength / retention strength of the retention members, at least one of the retention members is a double-walled retention member, and the coating is applied to a portion of the outer wall of the double-walled retention member that does not contact tissue. Optionally, the coating is applied to substantially all of the non-tissue contacting surfaces of one or both of the retention members. In order to further enhance the effect of the coating material, the surface area of ​​the outer wall of the retention member to which the coating is applied may be increased in size relative to prior art retention members. For example, the implantable device may be formed from a tubular element that forms a lumen through the implantable device, and the double-walled retention member may be formed by extending the wall of the tubular element radially outward to form the inner wall of the double-walled retention member, and then extending the wall of the tubular element radially inward from the periphery of the inner wall of the retention member and toward the longitudinal axis of the tubular element to form the outer wall of the double-walled retention member. The surface area of ​​the outer wall of the double-walled retention member may be increased in accordance with various principles of the present disclosure by extending the outer wall closer to the central longitudinal axis of the implantable device than prior devices. For example, in some embodiments, the surface area may be increased by about 85% compared to the outer wall of a previous similarly shaped (but not as large) retention member. Previously, such further extension of the outer wall toward the longitudinal axis of the retention member was not recognized as having potential advantages as described herein. The present disclosure recognizes the previously unrecognized advantage of increasing the surface area of ​​at least one outer wall of the retention member to increase the amount of coating material applied to such retention member, for example, to increase the pull-out strength of the retention member. In some embodiments, the outer diameter of the saddle (smaller than the outer diameter of the retention member) is not constant, but instead generally gradually increases from a narrow diameter in the central region of the saddle to a larger outer diameter of one or both of the retention members. Such a transition and gradual increase in the diameter of the saddle may allow the saddle to more closely conform to the contours of the anatomy of the deployment site to increase contact of the saddle with tissue and / or increase the surface area of ​​the saddle to enhance tissue ingrowth in the uncoated saddle.Additionally or alternatively, such transitions and gradual increases in diameter of the saddles may reduce fatigue on the material of the implantable device as it transitions from the saddle to one or both of the retention members. In some embodiments, the outer wall of at least one of the retention members extends inwardly to an inner diameter that is substantially the same (± about 0.5-0.1 mm and optionally ± about 0.1-2 mm, including 0.01 mm increments therebetween) as the diameter of the saddle through which the retention member extends. For example, the saddle may have an outer diameter that gradually increases to transition to the inner wall of the at least one retention member (e.g., at the point where the walls of the implantable device form a retention member that extends substantially radially outward from and generally perpendicular to its longitudinal axis). In some embodiments, the outer wall of the at least one retention member is approximately 500 mm. 2 More than, for example, about 750 mm 2 More than, for example, about 1000 mm 2 Exceeds (for example, 1014 mm 2 )(2mm between them 2 ) resulting in an increase in surface area (compared to a conventional similar device) of more than 100%, such as more than 130%, or even about 213%. Such an increase in surface area of ​​the outer wall may be applied to either or both of the retention members, regardless of whether the lengths (along the longitudinal axis of the implantable device) of the retention members are substantially the same or not. Additionally or alternatively, the length of at least one of the retention members may be increased to increase the surface area of ​​a side of the retention member that may contact tissue at the deployment site. In some embodiments, the increased length of at least one of the retention members may be achieved by increasing the distance between its inner and outer walls. In some embodiments, the increased length of at least one of the retention members may be in the form of an extension from the outer wall of the retention member.

[0035] In some aspects, tissue ingrowth into an implantable device, such as an implantable device formed according to various principles of the present disclosure, is further induced by abrasion (e.g., mucosal abrasion) of internal tissue at the placement site contacted by the implantable device. Various abrasion methods, including but not limited to the use of hook knives, hot biopsy forceps, hot snares, and the like, may be implemented to cause tissue abrasion and induce a healing response, thereby accelerating and increasing tissue ingrowth through the implantable device and reducing the likelihood of device migration. In accordance with various principles of the present disclosure, endoscopic mucosal resection (EMR) may be used in addition to or in lieu of mucosal abrasion. EMR has been found to more completely remove mucosa from tissues contacted by the implantable device and / or improve the consistency of the method of promoting tissue ingrowth into the implantable device. Such EMR techniques, in combination with improved configurations of the implantable device as described above, have been shown in clinical studies to significantly reduce the incidence of implantable device migration from the placement site. The EMR procedure may be performed using a hot snare or other suitable device, tool, instrument, etc., as known to one of skill in the art, to cut and remove tissue from at least a selected area of ​​the intended placement site of the implantable device. Areas of remaining tissue at the placement site may be ablated using mucosal abrasion or other suitable technique or procedure.

[0036] In accordance with one aspect of the present disclosure, the implantable device may be an occlusion device configured to regulate the flow of material through an anatomical structure across which the implantable device is positioned, for example, to occlude (as used herein, understood to include completely, or substantially completely, or even partially occlude, unless otherwise indicated) the flow of material through the anatomical structure. It is understood that, as used herein, terms such as occlude, block, prevent, inhibit, hinder, reduce, retard, and the like (and various grammatical forms thereof) may be used interchangeably, without any limitation intended, to indicate a reduction in the flow of material by more than 50% up to 100% (including 1% increments therebetween). For convenience, and without any limitation intended, reference will be made generally to implantable devices, but it is understood that the various principles and aspects of the present disclosure are applicable to implantable devices other than those that specifically occlude flow (such as, but not limited to, devices that hold tissues together in apposition, whether or not they form an anastomosis) and / or reduce the flow of material by less than 50%.

[0037] Various embodiments of an implantable device according to the principles of the present disclosure will now be described with reference to examples illustrated in the accompanying drawings. References herein to "one embodiment," "an embodiment," "some embodiments," "other embodiments," etc. indicate that one or more particular features, structures, and / or characteristics according to the principles of the present disclosure may be included in association with the embodiments. However, such references do not necessarily mean that all embodiments include the particular feature, structure, and / or characteristic, or that an embodiment includes all features, structures, and / or characteristics. Some embodiments may include one or more such features, structures, and / or characteristics in various combinations thereof. Furthermore, references in various places herein to "one embodiment," "an embodiment," "some embodiments," "other embodiments," etc. do not necessarily all refer to the same embodiment, nor are they necessarily separate or alternative embodiments that are mutually exclusive with other embodiments. It should be understood that when a particular feature, structure, and / or characteristic is described in association with one embodiment, such feature, structure, and / or characteristic may also be used in association with other embodiments, whether or not expressly described, unless expressly stated to the contrary. Furthermore, it is to be understood that such features, structures, and / or characteristics may be used or presented alone or in various combinations with each other to create alternative embodiments that are considered part of this disclosure, since it would be too cumbersome to describe all of the many possible combinations and subcombinations of features, structures, and / or characteristics. Furthermore, various features, structures, and / or characteristics are described that may be exhibited by some embodiments but not by other embodiments. Similarly, various features, structures, and / or characteristics or requirements are described that may be features, structures, and / or characteristics or requirements of some embodiments but may not be features, structures, and / or characteristics or requirements of other embodiments. Thus, the disclosure is not limited to only the embodiments specifically described herein, and the example embodiments disclosed herein are not intended to limit the broad aspects of the disclosure.

[0038] It will be understood that common features are identified by common reference elements, and for brevity and convenience, without any intention of limitation, the description of the common features will not be repeated throughout. For clarity, not all components with the same reference numbers are numbered. It will be understood that in the following description, similar elements or components among the various illustrated embodiments are generally designated with the same reference numbers incremented by a multiple of 100, and redundant descriptions are generally omitted for brevity. Furthermore, a particular feature in one embodiment may be used across different embodiments and is not necessarily labeled individually when appearing in different embodiments.

[0039] Referring now to the drawings, an example of an implantable device 100 formed in accordance with various principles of the present disclosure is shown in FIG. 1. The illustrated implantable device 100 has a proximal end 101, a distal end 103, and an intermediate region 105 between the proximal end 101 and the distal end 103. A proximal retention member 110 is provided along the proximal end 101 of the implantable device 100, a distal retention member 120 is provided along the distal end 103 of the implantable device 100, and a saddle portion 130 extends along the intermediate region 105 of the implantable device 100 between the proximal end 101 and the distal end 103. The saddle portion 130 may be configured to be placed through a body passageway, such as the pylorus P, as shown in FIG. 1. The retention members 110, 120 are wider than the saddle portion 130 and are positioned against respective body walls surrounding (e.g., extending outwardly from) respective entrances and exits of the body passageway to prevent movement of the implantable device 100 relative to the body passageway (distal / proximal or downstream / upstream relative to the direction of normal flow of matter through the body passageway). In the example environment shown in FIG. 1 for an implantable device 100 formed according to various principles of the present disclosure, the proximal retention member 110 is configured to be positioned within the stomach S (such as relative to the pylorus) and to prevent distal movement of the implantable device 100 into the duodenum D, and the distal retention member 120 is configured to be positioned within the duodenum D and to prevent proximal movement of the implantable device 100 into the stomach S. A lumen 107 may be formed through implantable device 100, and lumen 107 may be partially or completely occluded depending on the deployment site at which implantable device 100 is deployed and / or the purpose of implantable device 100 at the deployment site.

[0040] An example of an embodiment of an implantable device 200 formed according to various principles of the present disclosure is shown in Figures 2 and 3, with the implantable device 200 having a first (e.g., proximal) retention member 210 along its first (e.g., proximal) end 201, a second (e.g., distal) retention member 220 along its second (e.g., distal) end 203, and a saddle portion 230 along its intermediate region 205. In accordance with various principles of the present disclosure, at least one of the retention members 210, 220 may be increased in diameter (as opposed to similar prior art devices) to increase the surface area in contact with tissue at the placement site. The illustrated example of an embodiment of the implantable device 200 may be configured for placement across the pylorus P, as illustrated in Figure 1. The stomach retention member 210 may have a diameter larger than that of the duodenal retention member 220, such that it extends radially outward from the saddle portion 230 to increase the surface area in contact with the stomach S. Additionally, stomach retention member 210 may have a diameter that is larger than the diameter of duodenal retention member 220 (e.g., at least a 10% increase in diameter) and may be further increased to increase the surface area in contact with at least the pyloric antrum of the stomach. For example, the diameter of stomach retention member 210 may be about 30 mm, or even about 40 mm (including all increments between 30 and 40 mm), or even about 50 mm (including all increments between 40 and 50 mm) or greater.

[0041] In accordance with various principles of the present disclosure, surfaces of the implantable device 200 that contact tissue at the placement site are configured to promote tissue ingrowth along such surfaces. Coatings that may be applied for various purposes (e.g., to prevent passage of material through the walls of the device, and / or to provide structural rigidity / reduce flexibility, and / or to provide some degree of lubricity, such as to facilitate movement relative to the tissue or to prevent tissue detachment) may inhibit tissue ingrowth. In accordance with various principles of the present disclosure, such coatings are not provided on surfaces of the implantable device 200 that contact tissue at the placement site, thereby promoting tissue ingrowth into uncoated surfaces. In some embodiments, surfaces configured to promote tissue ingrowth include all surfaces configured to contact tissue at the placement site. In the example embodiment of the implantable device 200 illustrated in Figures 2 and 3, the surface of the saddle 230 (a portion of the saddle 230 or optionally the entire surface of the saddle 230) is configured to promote tissue ingrowth. Additionally or alternatively, at least some or all of the inwardly facing sides 212, 222 of the retention members 210, 220, respectively, are configured to promote tissue ingrowth relative to the retention members 210, 220. In the example embodiment of the occlusion device 200 shown in Figures 2 and 3, the retention members 210, 220 are double-walled retention members, the inwardly facing sides 212, 222 of the retention members 210, 220 are the inner walls of the double-walled retention members 210, 220, and the outwardly facing sides 214, 224 of the retention members 210, 220 are the outer walls of the double-walled retention members 210, 220. In some embodiments, all surfaces of the implantable device 200 configured to contact tissue at the deployment site are not coated with a material that can inhibit tissue ingrowth or are otherwise configured to promote tissue ingrowth. Additionally or alternatively, such surfaces may be treated (e.g., coated) with a material that promotes tissue ingrowth.

[0042] It should be understood that tissue ingrowth does not occur immediately after placement of the implantable device 200, and thus the implantable device 200 may undergo movement or other undesirable shifts in position relative to the placement site until sufficient tissue has grown to secure the implantable device 200 relative to the placement site. In accordance with various principles of the present disclosure, a coating material is applied to selected portions of the occlusion device 200 to strengthen (e.g., increase stiffness / reduce flexibility) the retention members 210, 220, thereby increasing their pull-out strength / resistance to movement. For example, the coating material may be applied to the outwardly facing side surfaces of the retention members 210, 220 that do not contact tissue at the placement site. In the example embodiment of the implantable device 200 shown in Figures 2 and 3, at least a portion of one or both of the individual outer walls 214, 224 of the retention members 210, 220 are coated with the coating material. In some embodiments, the entire surface of one or both of the individual outer walls 214, 224 of the retention members 210, 220 are coated with the coating material. 2 and 3, one or both of the respective outer walls 214, 224 of the retention members 210, 220 include axial extensions 216, 226, respectively, referred to herein for convenience and without any intent to be limiting, simply as "lips." The lips 216, 226 extend outwardly from the saddle portion 230 generally along the longitudinal axis LA of the implantable device 200 and generally have an outer diameter smaller than the outer diameter of the retention members 210, 220 through which the lips 216, 226 extend. The lips 216, 226 can serve a variety of purposes, such as to be grasped for removal and / or to facilitate finishing of the free ends of the elements from which the implantable device 200 is formed, and / or to add some stiffness to the retention members 210, 220 (especially if coated). As can be understood with reference to Figures 2 and 3, in accordance with various principles of the present disclosure, some or all of the outer surface of one or both of the lips 216, 226 is coated with a coating material such as is applied to the outer walls 214, 216 of the retention members 210, 220, such as to provide additional structural rigidity to the implantable device 200.

[0043] In accordance with various principles of the present disclosure, the surface area of ​​the individual outer walls 214, 216 of the retention members 210, 220 is increased to be greater than that typical of similar devices of the prior art. In other words, the diameter of the lips 216, 226 and / or the size of the portion of the lumen 207 extending through the outer walls 214, 216 is reduced relative to similar components of prior art devices (e.g., stents that typically have a maximum lip and lumen diameter throughout). The increase in surface area of ​​the individual outer walls 214, 216 of the retention members 210, 220 allows for a sufficient increase in coating material to be applied thereto to impart increased stiffness to the retention members 210, 220 and increase their individual pull-out force. In some embodiments, implantable devices formed in accordance with various principles of the present disclosure provide an increase of about 130% or more (compared to current similar devices) of the surface area that can be coated as described herein.

[0044] Various other modifications to the size, shape, configuration, and / or dimensions of the implantable device may be made in accordance with various principles of the present disclosure to resist migration of the device relative to the placement site. For example, the surface area of ​​the surface of the implantable device configured to contact tissue may be increased and configured to promote tissue ingrowth (e.g., not coated with a material that inhibits tissue ingrowth and / or coated with a material that promotes tissue ingrowth) to further reduce migration of the implantable device. In the example embodiment of the implantable device 300 illustrated in Figures 4 and 5, the implantable device 300 is configured for placement across the pylorus P, and the duodenal retention member 320 has an increased length to increase the surface area in contact with the tissue wall of the duodenum in which it is placed. Thus, the implantable device 300 illustrated in Figures 4 and 5 presents a greater surface area for tissue ingrowth than is presented by the corresponding retention member of the implantable device 200 illustrated in Figures 2 and 3. The exterior surface area of ​​the outer walls 312, 322 of the retention members 310, 320 may be increased as described above and coated with a coating material to reduce the flexibility of the retention members 310, 320, thereby increasing the pull-out strength of the retention members 310, 320, as can be understood with reference to FIG.

[0045] Additionally or alternatively, the length of the lip of at least one retention member of an implantable device 400 formed according to various principles of the present disclosure may be extended to increase the surface area of ​​the implantable device 400 for contacting tissue at the placement site, as illustrated in Figures 6 and 7. The extended lip 426 may advantageously be configured to promote tissue ingrowth within the extended lip 426 (e.g., not coated with a material that inhibits tissue ingrowth and / or coated with a material that promotes tissue ingrowth). The implantable device 400 shown in Figures 6 and 7 having an extended length lip 426 may be suitable for placement in the pylorus (as shown in Figure 1) to increase contact between the area of ​​the implantable device 400 (lip 226 extending from the duodenal retention member 420) and the duodenum. The present disclosure recognizes that increased stiffness may be imparted by the proximity of the walls of the dual-walled retention member. In accordance with various principles of the present disclosure, instead of extending the length of the retention member (the distance between the inner and outer walls of the retention member) to increase the surface area of ​​the retention member that contacts tissue at the placement site, the inner wall 422 and the outer wall 424 of the duodenal retention member 420 of the implantable device 400 shown in Figures 4 and 5 are closer to each other than the inner wall 322 and the outer wall 324 of the duodenal retention member 320 of the occlusion device 300 shown in Figures 4 and 5 to increase the stiffness of the retention member 420.

[0046] An implantable device having one or more features as described above may be constructed in a variety of non-limiting ways. In some embodiments, an implantable device having one or more features as described herein may be formed from a tubular element. In some embodiments, an implantable device formed according to various principles of the present disclosure is formed from a plurality of filaments formed into a tubular element. It is understood that the term filament is used for convenience and may be used interchangeably herein with terms such as wire, strand, fiber, strut, etc., without any limitation intended. In some embodiments, an implantable device is formed from a plurality of filaments that are braided, woven, interwoven, knitted, wound, twisted, looped (e.g., bobbinette style), knotted, or otherwise formed into a tubular element. In some embodiments, an implantable device is formed from a laser cut tube, which in some cases may be considered to form a plurality of struts that form the tubular element. In some embodiments, an implantable device is formed from a plurality of joined elongated elements. Implantable devices formed according to various principles of the present disclosure may be formed from biocompatible metallic or biocompatible polymeric materials or biocompatible alloys or combinations thereof. In other examples, the implantable devices may be constructed from polymeric materials (e.g., polyethylene terephthalate, poly(methyl methacrylate)). In yet other examples, the implantable devices may be constructed from combinations of metallic and polymeric materials. In yet other examples, the implantable devices may include bioabsorbable and / or biodegradable materials (e.g., poly(lactic-co-glycolic acid) polymers).

[0047] Formation of the wall of the implantable device as described above may leave a number of openings therethrough, such as between filaments or struts, etc. It is to be understood that the term opening is used for convenience and may be used interchangeably herein with terms such as space or gap, without any intended limitation. Placement of such a wall in contact with tissue may allow or encourage tissue to grow into the gaps in the wall, thereby securing the wall relative to the placement site.

[0048] To promote tissue ingrowth into the implantable device, tissue at the placement site may be pretreated in various ways, such as by abrasion, ablation, drug treatment, argon plasma coagulation (APC), etc., to promote, accelerate, and / or increase cell proliferation, such as the result of a healing response. Various forms of abrasion, including the use of hook knives, hot biopsy forceps, and hot snares, may be used to create abrasions of tissue, such as mucosal tissue of the gastrointestinal tract, such as in the region of the pylorus. In accordance with various principles of the present disclosure, improved induction of tissue growth may be achieved by performing endoscopic mucosal resection (EMR) on tissue at the placement site of the implantable device. In some embodiments, tissue is blebbed (e.g., by injection of a fluid such as sterile saline), the blebbed tissue is tensioned (e.g., with a vacuum), and the tensioned tissue is excised (e.g., with a hot snare or blade or other cutting instrument) to separate the mucosal tissue from the submucosal tissue at the excision site. For example, EMR may be advantageously performed on tissue surrounding and / or along the pylorus. Such a technique may more completely remove mucosa from tissue that is contacted by the implantable device, improving the consistency of tissue growth promotion methods performed prior to placement of the implantable device. Generally, EMR is a more consistent technique for enhancing tissue growth than prior techniques because it allows for a more easily definable (and generally greater) amount of tissue to be grasped and removed, and such action induces a healing response with the desired associated tissue growth.

[0049] For purposes of anti-migration, it is desirable to encourage tissue ingrowth and leave the surfaces of implantable devices formed according to various principles of the present disclosure free of coatings that may inhibit tissue ingrowth, although it will be understood that application of a coating to regions of the implantable device may be desirable to occlude the flow of materials through interstices in the walls of the device. Additionally or alternatively, application of a coating to the walls of an implantable device can strengthen the walls, such as by filling interstices in the walls, thereby reducing flexibility in the coated regions and strengthening such regions of the walls of the device. Such coatings may be formed from biocompatible polymeric materials (e.g., silicone, urethane, polyurethane, urethane polyether block amide (PEBA), polyethylene, polyethylene terephthalate (PET), polyvinylidene difluoride (PVDF), polytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene (ePTFE), polyester, polypropylene, polynaphthalene, Chronoflex®, C-Flex® thermoplastic elastomers, Krator® SEBS and SBS polymers, or similar biocompatible polymer blends and / or copolymers thereof and / or combinations thereof, and the like. Additional or other features or structures (e.g., barbs or looped projections) may be provided to promote tissue ingrowth in accordance with various principles of the present disclosure.

[0050] As discussed above, the surface area of ​​the retention members of implantable devices formed according to various principles of the present invention may be increased to increase the surface area available to be coated with a material that increases the pull-out strength of the coated retention members. Such enlarged retention members may be formed in a variety of ways. For example, the material of the tubular elements from which the implantable devices as disclosed herein are formed (e.g., the material of the filaments forming the braided or wire mesh tubular elements) may be a shape memory and / or thermoformable material, such as, but not limited to, nickel-titanium alloys (e.g., Nitinol) or cobalt-chromium-nickel-molybdenum alloys (e.g., Elgiloy®), or stainless steel. The configuration of the tubular elements may be set by shaping the tubular elements, such as by compressing or constraining or shrinking or pinching or otherwise narrowing (e.g., with a shape forming tool such as a mold) an intermediate region to form a saddle, and optionally by expanding end regions to form retention members that extend radially outward along one or both ends of the implantable device. In accordance with various principles of the present disclosure, at least one of the free ends of the tubular elements from which the implantable device is formed is retracted inwardly to a greater extent than in similar prior art devices to increase the surface area of ​​the outer wall of the retention member adjacent such free end. The present disclosure recognizes previously unrecognized advantages of increasing the surface area of ​​the outer wall of the retention member and decreasing the diameter of any lumen openings at the ends of the implantable device and / or the diameter of the lips of the implantable device to provide, for example, increased surface area for receiving coatings and to increase the overall pull-out force of the retention member. The implantable device thus formed may be treated (e.g., heated) in a manner known to those skilled in the art to set the formed tubular element into a desired shape, the details of which do not form part of this disclosure.

[0051] To facilitate endoscopic or transluminal (or otherwise, without the need for open surgery) delivery and placement and optional removal, implantable devices formed according to various principles of the present disclosure may be configured to transition or move between a collapsed or compact delivery configuration and an expanded deployment configuration. In some embodiments, the implantable device is formed to enable such configuration-shifting functionality. In some embodiments, the implantable device is formed from materials that may be advantageously used to enable expansion of the device to a desired deployment configuration, such as self-expanding and / or shape-memory materials. The implantable device may be configured to return to the collapsed or compact configuration to enable removal from the deployment site as desired and / or medically indicated. The shape or configuration or general structure of the device may enable transition to the collapsed or compact configuration in any of a variety of known or conventionally known manners, although the precise structure is not critical to the broad principles of the present disclosure.

[0052] It should be understood that, as described herein, an "embodiment" (as shown in the accompanying drawings) may refer to an exemplary representation of an environment or article or component in which a disclosed concept or feature may be provided or embodied, or may refer to a representation of a manner in which only the concept or feature may be provided or embodied. However, such illustrated embodiments should be understood as examples (unless otherwise specified), and other manners embodying the described concept or feature, as would be understood by a person skilled in the art having learned the concept or feature from the present disclosure, are within the scope of the present disclosure. In addition, although the figures may show one or more embodiments of a concept or feature together in a single embodiment of an environment, article, or component incorporating such concept or feature, it should be understood that such concepts or features should be understood as separate and distinct from one another (unless otherwise specified), and are shown together for convenience and are not intended to be limited to existing or used together. For example, features illustrated or described as part of an embodiment may be used separately or with one or more other features to obtain further embodiments. Thus, it is intended that the present subject matter covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[0053] From the foregoing, it should be understood that the various embodiments shown in the figures have several separate and independent features, each of which, at least alone, has its own advantages that are desirable, but not critical, for the presently disclosed implantable device. Thus, it is not necessary that all of the various separate features described herein be present in order to achieve at least some of the desired properties and / or advantages described herein. Only one of the various features may be present in an implantable device formed according to the various principles of the present disclosure. Alternatively, one or more of the features described with reference to one embodiment may be combined with one or more of the features of any of the other embodiments provided herein. That is, any of the features described herein may be mixed and matched to create hybrid designs, and such hybrid designs are within the scope of the present disclosure. Furthermore, throughout this disclosure, reference numbers are used to indicate schematic elements or features of the disclosed embodiments. The same reference numbers may be used to indicate elements or features that are not identical in form, shape, structure, etc., but provide similar functions or advantages. Additional reference signs (such as letters rather than numbers) may be used to distinguish similar elements or features from one another.

[0054] Although the embodiments of the present disclosure have been described with specific reference to medical devices and systems and procedures for treating the digestive system, it should be understood that such medical devices and methods may be used to treat tissues of the abdominal cavity, digestive system, urinary tract, reproductive tract, respiratory system, cardiovascular system, circulatory system, etc.

[0055] The above description has broad applicability and is presented for purposes of illustration and description, and is not intended to limit the disclosure to the form or forms disclosed herein. It should be understood that various additions, modifications, and substitutions may be made to the embodiments disclosed herein without departing from the concept, spirit, and scope of the disclosure. In particular, it will be apparent to those skilled in the art that the principles of the disclosure may be provided in other forms, structures, arrangements, ratios, and with other elements, materials, and components without departing from the concept, spirit, or scope, or characteristics thereof. For example, various features of the disclosure are grouped together in one or more aspects, embodiments, or forms for the purpose of streamlining the disclosure. However, it should be understood that various features of some aspects, embodiments, or forms of the disclosure may be combined with alternative aspects, embodiments, or forms. Although the disclosure is presented with respect to embodiments, it should be recognized that such individual features need not be present to achieve at least some of the desired properties and / or benefits of the subject matter or various separate features of the subject matter. Those skilled in the art will recognize that the present disclosure may be used with many modifications, or with modifications of structure, arrangement, size, materials, components, or otherwise used in the practice of the present disclosure that are specifically adapted to particular environments and operating conditions, without departing from the principles or spirit or scope of the disclosure. For example, elements shown as integrally formed may be composed of multiple parts, or elements shown as multiple parts may be integrally formed, the operation of elements may be reversed or otherwise changed, and elements may be sized or dimensioned differently. Similarly, although operations or acts or procedures are described in a particular order, this should not be construed as requiring such a particular order, or that all operations or acts or procedures are performed to achieve a desired result. Additionally, other implementations are within the scope of the following claims. In some cases, the acts recited in the claims may be performed in a different order and still achieve a desired result.The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the claimed subject matter being indicated by the appended claims and not limited to the foregoing description or the specific embodiments or arrangements described or illustrated herein. In view of the above, the individual features of any embodiment may be used and claimed separately or in combination with the features of that embodiment or any other embodiment, the scope of the subject matter being indicated by the appended claims and not limited to the foregoing description.

[0056] In the foregoing description and in the claims that follow, it is recognized that: As used herein, the terms "at least one," "one or more," and "and / or" are open-ended expressions that are both conjunctive and disjunctive in operation. The terms "a," "an," "the," "first," "second," etc. do not preclude a plurality. For example, as used herein, the term "a" or "an" entity refers to one or more of that entity. As such, the terms "a" (or "an"), "one or more," and "at least one" may be used interchangeably herein. All directional designations (e.g., proximal, distal, upper, lower, upward, downward, left, right, lateral, longitudinal, front, rear, top, bottom, upward, downward, vertical, horizontal, radial, axial, clockwise, counterclockwise, etc.) are used for identification purposes only to aid the reader in understanding this disclosure and / or serve to distinguish regions of related elements from one another and are not intended to limit the related elements with respect to position, orientation, or use, particularly in this disclosure. Connection designations (e.g., attached, coupled, connected, and joined) are to be interpreted broadly and may include intermediate members and relative movement of elements between a group of elements unless otherwise indicated. As such, connection designations do not necessarily imply that two elements are directly and in fixed relationship to one another. Identification designations (e.g., primary, secondary, first, second, third, fourth, etc.) are not intended to imply importance or priority and are used to distinguish one feature from another.

[0057] The following claims are hereby incorporated by reference into this detailed description, with each claim standing on its own as a separate embodiment of the present disclosure. In the claims, the term "comprises / comprising" does not exclude the presence of other elements, components, features, regions, integers, steps, operations, etc. In addition, although individual features may be included in different claims, they may in some cases be advantageously combined, and their inclusion in different claims does not imply that the combination of features is not feasible and / or advantageous. In addition, a reference to the singular does not exclude a plurality. Reference signs in the claims are provided merely as a clarifying example and should not be interpreted as limiting the scope of the claims in any way.

Claims

1. 1. An implantable device extending along a longitudinal axis and having a first end, a second end, and an intermediate region between the first end and the second end, a saddle along the intermediate region; a first retention member extending radially outward from the longitudinal axis along the first end; a second retention member extending radially outward from the longitudinal axis along the second end; at least a portion of a surface of the saddle and at least a portion of the inwardly facing surfaces of the first and second retention members facing toward the saddle are configured to promote tissue ingrowth; an implantable device, wherein the outwardly facing sides of the first and second retention members facing away from the saddle are sized such that a coating material provided on the sides increases the pull-out strength of the first and second retention members.

2. The outwardly facing side of at least one of the first retaining member or the second retaining member is about 500 mm ２ 13. The implantable device of claim 1 having a surface area greater than

3. 3. The implantable device of claim 1, wherein a lip extends axially from the second retention member a distance greater than the distance between the inwardly facing side and the outwardly facing side of the second retention member and is configured to promote tissue growth within the lip.

4. the first retention member and the second retention member each include a double-walled retention member having an inner wall along the inwardly facing side and an outer wall along the outwardly facing side; 4. The implantable device of claim 1, wherein a distance between the inner wall and the outer wall of the second retention member is greater than a distance between the inner wall and the outer wall of the first retention member.

5. 5. The implantable device of claim 1, further comprising a lip extending axially from at least one of the first retention member or the second retention member in a direction away from the saddle portion, the lip being coated with a coating material that reduces flexibility of the lip.

6. 6. The implantable device of claim 1, wherein the first retention member and the second retention member are of different sizes, shapes, configurations and / or dimensions.

7. the saddle portion is configured to be placed through the pylorus; the first retention member is configured to seat on a portion of the stomach surrounding the pylorus; 10. The implantable device of claim 1, wherein the second retention member is configured to extend into the duodenum extending from the pylorus and has an outer diameter smaller than an outer diameter of the first retention member.

8. 8. The implantable device of claim 1, wherein the saddle and inwardly facing sides of the first and second retention members facing toward the saddle have walls with gaps formed therein and are left uncoated to promote tissue ingrowth into the gaps.

9. 1. A method of forming an implantable device from a tubular element having a first end, a second end, an intermediate region between the first end and the second end, and a lumen formed therethrough, comprising: narrowing an intermediate region of the tubular element to form a saddle along the intermediate region; increasing a diameter of a portion of the tubular element along the first end of the tubular element greater than an outer diameter of the saddle to form an inner wall of a first retaining member facing the saddle and an outer wall of a first retaining member facing away from the saddle; increasing a diameter of a portion of the tubular element along the second end of the tubular element greater than an outer diameter of the saddle to form an inner wall of a second retaining member facing towards the saddle and an outer wall of a second retaining member facing away from the saddle; and retracting a first free end of the tubular element inwardly to have a diameter sufficiently smaller than an outer diameter of the first retaining member to provide a surface area sufficient to receive a coating material to increase stiffness of an outer wall of the first retaining member.

10. The method of claim 9 , wherein the first free end of the tubular element is drawn inwardly to have a diameter less than a maximum diameter of the saddle portion.

11. The method of claim 9 or 10, wherein the retention members are formed to have different sizes, shapes, configurations and / or dimensions.

12. 12. The method of claim 9, further comprising increasing a diameter of a portion of the tubular element along the first end of the tubular element such that an outer diameter of the first retaining member is greater than an outer diameter of the second retaining member.

13. 13. The method of claim 9, further comprising forming an inner wall of the second retaining member and an outer wall of the second retaining member to be greater than a distance between the inner wall of the first retaining member and the outer wall of the first retaining member.

14. 14. The method of claim 9, further comprising forming a lip extending axially from the second retaining member in a direction away from the saddle, the lip having a length greater than a distance between an inner wall of the second retaining member and an outer wall of the second retaining member.

15. 15. The method of any one of claims 9 to 14, further comprising coating an outer wall of the second retention member to configure an outer surface of the lip to promote tissue ingrowth.

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