Adjustable lumen apposing stent

Abstract

To provide medical devices for facilitating the flow of fluids and materials in and / or between adjacent body lumens, for example, a stent which maintains an open flow passage between body lumens.SOLUTION: A stent 100 may have a constrained configuration and an expanded configuration. In the expanded configuration, the stent may have first and second retention members 102 and 104, and a saddle region 106 extending between the retention members. The saddle region may comprise a coil 108 configured to apply a restoring force to tissue surfaces respectively apposed to the first and second retention members.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present disclosure relates generally to the field of medical devices. In particular, the present disclosure relates to medical devices for facilitating the flow of fluids and materials, such as stents for maintaining an open flow path between or within a body lumen. [Background technology]

[0002] Placement of a self-expanding metal stent (SEMS) within an anatomical area (e.g., a body lumen, passageway, vessel, duct, etc.) can allow fluid communication from one area to another. For example, a stent can allow the flow of fluid from one body lumen to another.

[0003] Stents are typically provided in incremental sizes, with an individually sized stent being selected for use in a procedure based on the anatomical dimensions of the patient's tissue. An improperly sized stent may cause excessive irritation to the apposed tissue, for example if the stent is too short to accommodate the width of the tissue held between the retention members of the stent. In some cases, an improperly sized stent may prevent the formation of a seal between the stent and the apposed tissue. As a result, a stent that is not optimally sized for the target patient's anatomy may result in tissue damage and / or other unintended consequences, such as fluid leakage around the stent, thereby posing discomfort and / or risk of danger to the patient.

[0004] With the above considerations in mind, a variety of beneficial medical outcomes may be achieved by the devices and / or methods of the present disclosure. Summary of the Invention

[0005] In one aspect, a stent can include an elongate body having a restrained configuration. The elongate body can have an expanded configuration having a first portion expanded to become a first retention member. The elongate body can have a second portion expanded to become a second retention member. The elongate body can have a saddle region. The saddle region can define a lumen extending between the first retention member and the second retention member.

[0006] In other aspects described, the first retaining member can comprise a first flange and a second flange configured to appose the first and second surfaces of the first tissue, the second retaining member can comprise a third flange and a fourth flange configured to appose the first and second surfaces of the second tissue, or both. The first retaining member can comprise a mesh structure, the second retaining member can comprise a mesh structure, or both. In many embodiments, the coil can extend along the entire length of the saddle region. The coil can be configured to apply a tension force between the first retaining member and the second retaining member. The coil can be configured to apply a laterally outward force between the first retaining member and the second retaining member. The saddle region can comprise two or more coils. The two or more coils can be joined end to end. The two or more coils can be joined at a central point. Each of the two or more coils can comprise a different spring constant. The saddle region can comprise at least one curved portion. The first retention member, the second retention member, and the coil may be continuously formed of wire. The first retention member may include a first surface substantially perpendicular to a longitudinal axis of the saddle region, the first surface configured to appose a first tissue, the second retention member may include a second surface substantially perpendicular to a longitudinal axis of the saddle region, the second surface configured to appose a second tissue, or both. The coil may include a shape memory material. The stent may include a cover.

[0007] In another aspect, the hollow body can have a constrained configuration and an unconstrained configuration. The hollow body in the unconstrained configuration can include a first retention member, a second retention member, and a central region therebetween. The central region can include a coil configured to generate a force to return toward a predetermined position when deflected. The first retention member and the second retention member can be configured to transfer a force to tissue engaged by the first retention member, tissue engaged by the second retention member, or both.

[0008] In other described aspects, the coil can be configured to apply a tension force between the first and second retention members. The coil can be configured to apply a lateral outward force between the first and second retention members. The first retention member, the second retention member, and the coil can be continuously formed of wire.

[0009] In yet another aspect, a stent can include a first retention member configured to appose a first tissue layer, a second retention member configured to appose a second tissue layer, and a saddle region extending therebetween. The saddle region can include a coil configured to affect spacing between the first and second tissue layers.

[0010] In other described aspects, the coil may be configured to apply tension between the first and second retention members. The coil may be configured to apply a lateral outward force between the first and second retention members. The first and second retention members and the coil may be continuously formed of wire. The coil extends along the entire length of the saddle region.

[0011] Non-limiting examples of the present disclosure are described with reference to the attached figures, which are schematic and not intended to be drawn to scale. In the figures, each identical or nearly identical component shown is typically represented by a single number. For clarity, not every component is labeled in every figure, or every component in each embodiment of the present disclosure is shown unless illustration is necessary to enable a person skilled in the art to understand the present disclosure. [Brief description of the drawings]

[0012] [Figure 1A] 1 is a side view of a self-expanding stent according to one or more embodiments described herein. [Figure 1B] FIG. 2 is another side view of a self-expanding stent according to one or more embodiments described herein. [Figure 1C] FIG. 2 is another side view of a self-expanding stent according to one or more embodiments described herein. [Figure 2A] FIG. 1 illustrates a self-expanding stent according to one or more embodiments described herein. [Figure 2B] 4 is another diagram showing a self-expanding stent according to one or more embodiments described herein. [Diagram 3] 1A-1D illustrate an exemplary use of a stent according to one or more embodiments described herein. [Figure 4] 1 illustrates an exemplary use of a self-expanding stent according to one or more embodiments described herein. [Diagram 5] FIG. 1 illustrates an exemplary curved self-expanding stent according to one or more embodiments described herein. [Figure 6] FIG. 2 illustrates another exemplary curved self-expanding stent according to one or more embodiments described herein. [Figure 7] 1 is a side view of a self-expanding stent according to one or more embodiments described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Placement of a self-expanding metal stent (SEMS) within an anatomical area (e.g., a body lumen, passageway, vessel, duct, etc.) can allow fluid communication from one area to another. For example, a stent can allow the flow of fluid from one body lumen to another.

[0014] Stents are typically provided in incremental sizes, with individually sized stents being selected for use in a procedure based on the anatomical dimensions of the patient's tissue. For example, a particular stent may be selected to match the dimensions of one or more body lumens, the length of a desired passageway intended to be formed by the stent, the distance between tissues to be apposed by the stent, or other dimensions.

[0015] As can be appreciated, it can be difficult for a physician to accurately obtain the dimensions of a patient's tissue so that an optimally sized stent can be selected. For example, tissue movement and / or lack of clear visibility of the tissue can impair the physician's ability to select a stent that is appropriately sized for use in a procedure.

[0016] An improperly sized stent may cause excessive irritation to adjacent tissues, for example, if the stent is too long and its ends extend beyond the apposed tissue and out of the body lumen, thereby interacting undesirably with other tissues. In some cases, an improperly sized stent may prevent the formation of a seal between the stent and the apposed tissue. For example, the stent may not have sufficient length to effectively bridge the tissues and may therefore be prone to movement, which may result in an inability to properly form a seal with the tissue positioned between the retaining members of the stent. As a result, an improperly sized stent may result in tissue damage and / or other unintended consequences, such as leakage of fluids around the stent, thereby causing discomfort and / or other symptoms to the patient.

[0017] With the above considerations in mind, various beneficial medical outcomes may be achieved by the devices and / or methods of the present disclosure. For example, a stent according to one or more embodiments described herein may have an automatically adjustable length to accommodate various applications. Accordingly, physicians may not need to approximate a desired stent size as is required with conventional stents.

[0018] The present disclosure is not limited to the specific embodiments described, and may vary accordingly. The technical terms used herein are merely for the purpose of describing specific embodiments, and are not intended to limit the scope of the appended claims. Unless otherwise specified, all technical terms used herein have the same meaning as commonly understood by those skilled in the art to which the present disclosure belongs. Finally, although the embodiments of the present disclosure are described with particular reference to medical devices and systems and procedures related to the gastrointestinal system, it should be understood that such medical devices and methods may be used in tissues such as the abdominal cavity, digestive system, thoracic cavity, urinary and reproductive organs.

[0019] As used herein, "proximal end" refers to the end of the device that is located along the device closest to the medical professional when introducing the device into a patient, and "distal end" refers to the end of the device or object that is located along the device furthest from the medical professional during implantation, positioning, or delivery.

[0020] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is used generally in its sense including "and / or" unless the content clearly dictates otherwise.

[0021] As used herein, the conjunction "and" includes each of the structures, components, features, etc. so connected, unless the content clearly dictates otherwise, and the conjunction "or" includes one or the other of the structures, components, features, etc. so connected, singly as well as in any combination and number, unless the content clearly dictates otherwise.

[0022] All numerical values ​​are assumed herein to be modified by the term "about", whether or not expressly indicated. The term "about" in the context of numerical values ​​generally refers to a range of numbers that one of ordinary skill in the art would consider equivalent to the recited value (e.g., having the same function or result). In many cases, the term "about" may include numbers that are rounded to the nearest significant numerical value. Other uses of the term "about" (e.g., in non-numerical contexts) may be assumed to have their conventional, customary definition as understood from and consistent with the context of this specification, unless otherwise specified. Recitation of numerical ranges by endpoints includes all numbers within that range, including the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0023] It is noted that references herein to "one embodiment," "some embodiments," or "other embodiments," etc., indicate that the described embodiment may include one or more particular features, structures, and / or characteristics. However, such enumeration does not necessarily mean that all embodiments include that particular feature, structure, and / or characteristic. Additionally, when that particular feature, structure, and / or characteristic is described in connection with one embodiment, it should be understood that such feature, structure, and / or characteristic may also be used in connection with other embodiments, with or without explicit description, unless expressly stated otherwise.

[0024] The detailed description should be read with reference to the drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention.

[0025] 1A-C illustrate an exemplary stent according to one or more embodiments herein. The stent 100 can include first and second retention members 102, 104 coupled to one another via a saddle region 106 extending therebetween. FIG 1A illustrates the stent 100 in a first configuration (e.g., an expanded configuration), FIG 1B illustrates the stent 100 in an intermediate configuration (e.g., a partially expanded configuration), and FIG 1C illustrates the stent 100 in a second configuration (e.g., a compressed configuration).

[0026] The first and second retention members 102, 104 can each form a flange or other extension having a diameter greater than the diameter of the saddle region 106. In many embodiments, one or both of the first and second retention members 102, 104 can be configured to contact a tissue surface. For example, the first retention member 102 can appose or otherwise engage a tissue surface (not shown) along the first axial outer surface 116, the first radial outer surface 126, and / or the first axial inner surface 118. The second retention member 104 can appose or otherwise engage a tissue surface (not shown) along the second axial outer surface 122, the second radial outer surface 128, and / or the second axial inner surface 120. Thus, in some embodiments, the stent 100 can be configured to hold opposing tissue surfaces together, while in other embodiments, the stent can be configured to keep opposing tissue surfaces apart. For example, the stent 100 may be deployed to appose two or more tissue walls along the first and second axial outer surfaces 116, 122 or along the first and second axial inner surfaces 118, 120. In another example, the stent 100 may be deployed (e.g., within a single body lumen) to engage tissue along the first and second radially outer surfaces 126, 128. The first axial outer surface 116, the first axial inner surface 118, the second axial inner surface 120, and / or the second axial outer surface 122 may each comprise a flat surface (e.g., a surface that is substantially perpendicular or angled (not shown) to a longitudinal axis AA extending through the stent 100), or they may comprise a surface or surfaces having one or more curvatures (not shown). The first radially outer surface 126 and / or the second radially outer surface 128 can comprise a flat surface (e.g., a surface that is substantially parallel to the longitudinal axis AA or that is angled (not shown)), or a surface having one or more curvatures (not shown).The first and second retention members 102, 104 may be formed of wire, one or more braids, mesh structures, etc., and may be formed of one or more metals, polymers, or other suitable materials. In many embodiments, one or more of the first and second retention members 102, 104 may comprise a shape memory material, such as Nitinol.

[0027] An elongated body, hollow body, central region, or saddle region, such as saddle region 106, can extend between the first retention member 102 and the second retention member 104 of the stent 100. The saddle region 106 can comprise a tubular structure, which in some embodiments can be in the form of a cylinder and a line, and / or can comprise one or more curves (see FIGS. 5-6). A lumen 124 can extend along the longitudinal axis AA of the stent 100 (e.g., through the first retention member 102, the saddle region 106, and the second retention member 104) along the entire length of the stent. In many embodiments, the lumen 124 can be configured to allow fluid flow through the stent 100 such that fluid can flow out or move between tissues coupled to the stent.

[0028] In various embodiments, the first and / or second retention members 102, 104 can include a lip or protrusion 110 on at least one end thereof. The lip or protrusion 110 (collectively referred to herein as "lip" for simplicity) can serve to guide flow therethrough and / or provide a surface for a user to grip during placement and / or removal of the stent 100. In the illustrated embodiment, the lip 110 of the first retention member 102 and / or the lip 112 of the second retention member 104 can extend longitudinally along the axis AA away from the respective flanges of the retention members. The lips 110, 112 can include a diameter that is the same as, smaller than, or larger than the diameter of the saddle region 106, lumen 124, or corresponding first or second retention member 102, 104.

[0029] The saddle region 106 can include at least one spring member, such as a coil 108. The coil 108 can extend along a portion of the saddle region 106 or along the entire length of the saddle region. The coil 108 can be formed of flat wire, round wire, or a combination thereof. The coil 108 can comprise a single wire or multiple wires and can be made of a metal, polymer, or other suitable elastic material. In many embodiments, the coil 108 comprises a shape memory material, a non-limiting example of which is Nitinol. In various embodiments, the coil 108 can be formed separately from the first and second retention members 102, 104 of the stent 100. For example, the coil 108 can be formed and then attached to one or more of the retention members 102, 104 by glue, welding, or other suitable attachment methods. Alternatively, the coil 108 may be formed continuously with one or more of the first and second retention members 102, 104 (e.g., formed by at least one wire of the first and / or second retention members) such that the coil is integral with the first and / or second retention members. In some embodiments, the coil 108 is formed of the same material used to form the first and second retention members 102, 104, while in other embodiments, the coil is formed of a material different from that of the first and / or second retention members. Although the coil 108 is shown to substantially form the saddle region 106, the saddle region 106 may additionally include one or more portions of a braided and / or woven saddle region in addition to the coil 108, as described with respect to the hoop 708 of FIG. 7. In some embodiments, the coil 108 may be embedded in a stent weave pattern (not shown).

[0030] Various stents described herein can include at least one coil 108 having a relaxed configuration (i.e., when little or no external force is applied) and a biased configuration (i.e., when an external compressive or elongation force is applied). In many embodiments, the relaxed configuration can be preset by application of heat. Compression or expansion of the coil 108 along the transverse axis AA can then impart a desired biasing force between the first retention member 102 and the second retention member 104. In other words, the coil 108 can generate a restoring force that tends to return the coil 108 and the first and second retention members 102, 104 to a predetermined position. FIG. 1A shows the stent 100 in a first configuration, in which the first and second retention members 102, 104 are separated to expand the coil 108 along the longitudinal axis AA. As a result, in the first configuration, the coil 108 provides a bias to the first and second retention members 102, 104 that tends to move the first and second retention members toward one another in the direction of arrow A to assume the second configuration shown in FIG. 1B or 1C. For example, the stent 100 can move in the direction of arrow A from the first configuration of FIG. 1A through the intermediate configuration shown in FIG. 1B toward the compressed configuration shown in FIG. 1C. As will be appreciated, this may enable the stent 100 to adjust the distance between the first retention member 102 and the second retention member 104) to accommodate various anatomical geometries. For example, the stent 100 can automatically adjust its length to span tissue layers (not shown) of various thicknesses.

[0031] As mentioned, the stent 100 can be configured to bias the first and second retention members 102, 104 toward or away from each other. For example, the first configuration of FIG. 1A can be a relaxed configuration, while the second configuration of FIG. 1C can be a compressed configuration. Alternatively, the second configuration of FIG. 1C can be a relaxed configuration, while the first configuration of FIG. 1A can be an extended configuration. In yet other embodiments, the intermediate configuration of FIG. 1B can be a relaxed configuration, while the configurations of FIGS. 1A and 1C can be an extended configuration (FIG. 1A) or a compressed configuration (FIG. 1C) in which the first and second retention members 102, 104 are biased to tend to return to the relaxed state of FIG. 1B.

[0032] In some embodiments, the first and / or second retention members 102, 104 may be configured to appose tissue, such as the first and second tissue layers 308, 310 as described with respect to FIG. 3, such that the tissue portions are held together or kept apart, depending on the requirements of a particular procedure. Thus, the first and second retention members 102, 104 may be configured to transfer a force (from compression or expansion) generated by the coil 108 to the tissues appose by the first retention member, the tissues appose by the second retention member, or both. In some embodiments, the coil 108 may be configured to provide a desired spacing between the tissue layers via the first and second retention members 102, 104. In some embodiments, the first and second retention members 102, 104 may be configured to be deployable within a single body lumen (e.g., to affect the diameter of the body lumen along the length of the stent 100, not shown).

[0033] For example, the first and / or second outer surfaces 116, 122 can be configured to appose the respective tissue surfaces such that the first and second retention members 102, 104 are biased laterally outward (e.g., along arrow B in FIG. 1C ). Thus, the stent 100 can be positioned between two tissue layers to apply a force to them to either press them together (e.g., to improve a seal between the respective first and / or second outer surfaces 116, 122 and the apposed tissue) or to keep them apart (e.g., to keep a diseased tissue layer separate from a healthy tissue layer and / or to provide a space between the two tissues that is accessible for another procedure or use).

[0034] In some non-limiting exemplary embodiments, the first and / or second inner surfaces 118, 120 of the first and second retention members 102, 104 can appose the respective tissue surfaces to hold the tissue surfaces together. In other non-limiting exemplary embodiments, the first and / or second outer surfaces 116, 122 of the first and second retention members 102, 104 can appose the respective tissue surfaces to keep the tissue surfaces apart. In either case, the tissue layers can be effectively bridged by the stent 100, which can create a fluid flow path therebetween.

[0035] In many embodiments, a covering, coating, or other layer (collectively referred to herein for simplicity as cover 114) may be applied to or otherwise coupled to stent 100 to encapsulate at least a portion of the stent. As will be appreciated, providing a covering for at least a portion of stent 100 may prevent tissue from catching, catching, or otherwise engaging a portion of the stent in a manner that may interfere with the desired operation. Cover 114 may comprise, for example, silicone or other polymeric material, or combinations thereof. For example, cover 114 may comprise polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, aromatic polycarbonate-based thermoplastic urethane, and / or other materials, and the like. Cover 114 may be applied to stent 100, such as by dip coating, painting, spraying, or other known deposition methods, or combinations thereof. Alternatively, the covering 114 may be formed separately from the stent 100 as a sheet or sleeve and then positioned about the stent and attached, such as by glue, one or more ties, shrink fitting, or other suitable attachment methods. In some embodiments, the covering 114 may be configured to stretch or otherwise deform or deflect in accordance with a corresponding deformation or deflection of the stent 100. In some non-limiting examples, the covering 114 may be configured to have less elasticity than the coils 108 such that it may contribute to biasing the stent 100 to return to a relaxed configuration when the stent is deformed.

[0036] Although the description of the stent 100 in Figures 1A-C has thus far been made in connection with a coil 108 for biasing the first and second retention members 102, 104 together or apart, it will be understood that other biasing members, such as an elastic band arrangement or the like, may be used in place of a coil.

[0037] 2A-B, an exemplary coil arrangement is described in more detail. The stent 200 can comprise a first retention member 202, a second retention member 204, and a saddle region 206 comprising a coil 208 made from one or more wires 226 used to form the first and second retention members. In this manner, the coil 208 is integrally formed with the first and second retention members 202, 204. FIG. 2A shows the stent 200 in a diametrically expanded configuration, while FIG. 2B shows the stent 200 in a compressed configuration.

[0038] In the expanded configuration, the first and / or second retention members 202, 204 of the stent 200 may be configured to appose tissue layers similar to the first and second retention members 102, 104 described with respect to Figures 1A-C. In contrast to the embodiment of Figures 1A-C, the first and second outer surfaces 216, 220 and the first and second inner surfaces 218, 222 of the first and second retention members 202, 204 comprise curved surfaces. In some examples, the curved inner and outer surfaces on the first and second retention members 202, 204 may allow the members to engage the respective tissue layers atraumatically or with reduced risk of abrasion to the tissue layers compared to flat or angled surfaces. The first and second retention members 202, 204 may include respective lips 210, 212 extending longitudinally away from the respective retention members 202, 204 along the axis AA, similar to the lips 110, 112 described with respect to Figures 1A-C.

[0039] The retention members 202, 204 may be formed of one or more wires 226 that may be formed into a coil 208 along the saddle region 206. For example, a single wire 226 may be wrapped, braided, or woven into the first and second retention members 202, 204 such that a portion or portions of the wire 226 extend between the retention members. The wire 226 may then be gathered and / or twisted to form the coil 208. In another example, multiple wires 226 may be braided, woven, or formed into a mesh structure to form the first and / or second retention members 202, 204. The portions of the wire 226 that extend between the first and second retention members 202, 204 may then be gathered and / or twisted to form the coil 208. Some or all of the wires 226 used to form the first and / or second retention members 202, 204 may also form the coil 208. In another example (not shown), the stent 200 may be made from a single wire 226 that is woven to form the first retention member 202, stretched into a coil 208 along the axis AA, and then woven at a second end to form the second retention member 204.

[0040] Coil 208 can function in the same manner as coil 108 as described with respect to FIGS. 1A - C. Thus, coil 208 can be configured to be biased such that the first and second retaining members 202, 204 separate (as in FIG. 1A, etc.), biased to come together (as in FIG. 1C, etc.), or biased to an intermediate position (as in FIG. 1B, etc.). It will be appreciated that the stiffness of coil 208 (e.g., its holding strength, restoring force, or biasing force) can be increased, for example, linearly, by increasing the number of wires and / or the wire thickness used to form the coil. Thus, the stent 200 can be configured to have a predetermined biasing force for a particular application or use with a particular type of tissue. In some embodiments, the stent 200 can have a spring force within the range described in connection with stent 100 as described with respect to FIGS. 1A - C.

[0041] The saddle region 206 can extend between the first retaining member 202 and the second retaining member 204, similar to the saddle region 106 as described with respect to FIGS. 1A - C. The lumen 224 can extend along the entire length (“L1”) of the stent 200 to provide a flow path through which fluid can move through the stent. For simplicity, stent 200 is shown in FIGS. 2A - B without a cover, but it will be appreciated that the stent may comprise a coating or covering as described with respect to stent 100 of FIGS. 1A - C.

[0042] In many embodiments, the stents described herein may be delivered to a patient tissue site in a radially compressed or constrained state (referred to as a delivery configuration) for inclusion within a lumen 228 of a catheter or other delivery device. When the stents are positioned within a patient, they may be released from the delivery device and assume an expanded, unconstrained, or deployed configuration. The stents may be self-expanding stents or may be expanded, for example, by a balloon. The expanded configuration of the stent 200 may be pre-set (e.g., by heat setting) such that the stent 200 has a predetermined length L1 and a predetermined diameter "D1" in the expanded or deployed configuration. FIG. 2B illustrates the stent 200 in an exemplary constrained configuration, for example, having a diameter "D2" smaller than D1 such that the stent 200 is disposable within the delivery device lumen 228. In the delivery configuration, the stent 200 may be elongated along the longitudinal axis AA to assume a length "L2" greater than L1. As will be appreciated, any or all of the components of the stent 200 may be longitudinally elongated and / or radially reduced when the stent is in a constrained configuration. It is noted that FIG. 2B illustrates the individual elements of the stent 200 (e.g., the lip 210, which has a distinctly smaller diameter compared to the retention member 202) as having distinct radial dimensions. However, it will be appreciated that the stent 200 may have a constrained configuration in which the individual elements are substantially constant in diameter along the length of the stent. In some embodiments, the coil 208 may be expanded or stretched when in the constrained configuration to have a smaller diameter and / or to approximate a linear shape. The stent 200 may be configured to automatically move from the constrained configuration to the expanded configuration upon release from the constraint, such as when the stent is formed of a shape memory material. It will be appreciated that the stent 100 described in connection with FIGS. 1A-C may include delivery and deployment configurations similar to those described in connection with the stent 200.

[0043] 3 illustrates an exemplary deployment sequence of a stent 100 according to one or more embodiments described herein. For simplicity, the method will be described with reference to stent 100, however, it will be understood that the method may be applied to any of the stents described herein.

[0044] As mentioned, a delivery shaft such as a catheter 316 may be used to deliver the stent 100 in a constrained delivery configuration to a desired location within or adjacent to a patient's tissue. The stent 100 may be disposed about an inner member 302 of the catheter 316 when the stent is deployed from the catheter (i.e., over an outer member 304 that may hold the stent 100 in a radially compressed delivery configuration). As can be seen, the inner member 302 is disposed through the lumen 124 of the stent 100 such that a tip 306 of the catheter is disposed beyond the stent. In some embodiments, the tip 306 may be a tissue-cutting element, such as an electrocautery tip.

[0045] The inner member 302, the outer member 304, and the stent 100 may be advanced together in the direction of arrow C through first and second openings 318, 320 formed in the first and second tissue layers 310, 308. When so positioned, the first retention member 102 is disposed within a body lumen 312 associated with the first tissue layer 308, while the second retention member 104 is disposed within a body lumen 314 associated with the second tissue layer 310. When the outer member 304 is retracted in the direction of arrow D, the first retention member 102 expands within the body lumen 312 and the second retention member 104 expands within the body lumen 314 with the coil 108 disposed therebetween. To facilitate proper placement of the stent 100, the inner member 302 and / or the outer member 304 may include one or more echogenic, radiopaque, and / or visual markers.

[0046] As shown, the stent 100 bridges the first and second tissue layers 308, 310. The coil 108 is configured to bias the first and second retention members 102, 104 toward one another. Thus, the coil 108 can apply a force to the respective first and second tissue layers 308, 310 via the first and second inner surfaces 118, 120 to draw the tissue layers together. The deployment system, including the inner member 302, outer member 304, and tip 306, can be removed through the lumen 124 leaving the stent 100 in place between the first tissue layer 308 and the second tissue layer 310.

[0047] FIG. 4 illustrates a stent 400 disposed within tissue according to one or more embodiments. The stent 400 includes one or more features similar to those described above in connection with stents 100 and 200, such as saddle region 106, coil 108, cover 114, and lumen 124. However, in the embodiment of FIG. 4, retention members 402 and 404 include a multi-flange structure that may more securely appose tissue layers 308, 310 by interacting with opposing sides of each tissue layer. For example, retention member 402 may include a first flange 422 having surfaces 406, 408 and a second flange 424 having surfaces 410 and 412. Retention member 404 may include a third flange 426 having surfaces 414, 416 and a fourth flange 428 having surfaces 418, 420. Any of the surfaces 406, 406, 410, 412, 414, 416, 418, and 420 may be configured to appose tissue, but in many embodiments, the multi-flanged retention members may be configured to hold tissue layers between the flanges of each retention member. Thus, the surfaces 408, 410 may be deployed to appose the first tissue layer 308, and the surfaces 416, 418 may be deployed to appose the second tissue layer 310. The stent 400 may be deployed using a method similar to that described with respect to FIG. 3, except that the first flange 422, the second flange 424, the third flange 426, and the fourth flange 428 may be deployed sequentially to appose the respective tissue layers. As shown in FIG. 4, the stent 400 spans the first and second tissue layers 308, 310. The coil 108 is configured to bias the first and second retention members 102, 104 away from one another. Thus, the coil 108 applies a force via surfaces 410, 416 to the respective first and second tissue layers 308, 310, pushing the tissue layers apart (e.g., along arrow E). The deployment system (not shown) may be removed leaving the stent 400 in place between the first tissue layer 308 and the second tissue layer 310. It will be appreciated that one or both of the retention members 402, 404 may alternatively include fewer or more than two flanges each (not shown).

[0048] 5-6 show alternative stent configurations according to various embodiments described herein. For simplicity, each stent 500, 600 of FIGS. 5-6 may have the same or similar features and functions as the stent 100 described with respect to FIGS. 1A-C, except that the saddle region 506, 606 of the stent 500, 600 may have a non-linear shape, and may alternatively or additionally include the dual flange retention members 402, 404 described with respect to FIG. 4. As can be seen, the saddle region 506 of FIG. 5 is curved along its length, while the saddle region 606 of FIG. 6 includes a pair of curved portions 610, 612. The curved stents 500, 600 may be useful for curving along blood vessels and organ surfaces or areas that may be difficult to reach. These are two non-limiting examples of curved stents, and it will be understood that a stent according to the present disclosure may comprise any number of curves, turns, bends, etc., including the same or different radii of curvature, corresponding inflection points, etc. It will be understood that the radii of curvature of the curved portions 506, 610, and 612 may be optimized in conjunction with the spring constant, length, or other aspects of the stent 500, 600 to accommodate corresponding stresses that the stent 500, 600 may encounter after deployment. The curves may be pre-set (e.g., by heat setting) in the expanded configuration. Although the coils 508, 608 of the stent 500, 600 are shown to comprise round wire, it will be understood that flat wire, gathered wire, or any other coil structure disclosed herein may comprise one or more curves.

[0049] 7 illustrates an additional embodiment according to the present disclosure, in which a stent 700 includes a saddle region 706 that includes multiple coils 702, 704. The stent 700 can have the same or similar features and functions as the stent 100 described in connection with FIGS. 1A-C, except that the saddle region 706 can include two or more coils 702, 704, which in many embodiments can have different thicknesses, spring constants, resistance to deformation, resilience, diameters, or other characteristics. For example, the first coil 702 is shown formed from a thicker wire than the second coil 704, and thus the first coil 702 can have a greater spring force than the coil 704. Variable resilience coils can be useful, for example, for use in body passageways having different applied pressures or geometries. For example, the portion of the stent 700 corresponding to the second coil 704 may be more easily deformable about the longitudinal axis AA than the portion corresponding to the first coil 702, thereby making the stent 700 more suitable for use in portions of a tortuous body passageway. It will be appreciated that instead of providing coils with different wire thicknesses, different spring constants between the first coil 702 and the second coil 704 may also, or alternatively, be implemented by using different materials for each. In addition, while two coils are shown, it is contemplated that a greater number of coils may be used. Furthermore, a single coil having continuously variable and / or graduated dimensions may also be used to provide a stent with variable stiffness along its length.

[0050] The first and second coils 702, 704 of the stent 700 may be directly bonded to one another by welding, adhesives, etc., or they may be bonded by one or more connecting members, such as rings, hoops, etc., while maintaining an open passage of the lumen of the stent. The first and second coils 702, 704 may have the same or different lengths and be joined at a center point or elsewhere along the saddle region. For example, in the illustrated embodiment, the first and second coils 702, 704 are each bonded to a hoop 708 at approximately the midpoint of the stent 700. It will be appreciated that the coils may be bonded end-to-end or in series as shown in FIG. 7, or may be bonded in tandem or parallel around a common or separate lumen (not shown). Although hoop 708 is shown as having a continuous (e.g., solid) circumference, it will be understood that hoop 708 may alternatively comprise a braided or woven stent saddle portion that may be formed continuously or separately from coil 702 and / or coil 704. The various coils of the stent may also be made of the same or different materials. The embodiments are not limited herein.

[0051] It will be understood that various embodiments may include alternative retention member designs. Although not shown for simplicity, the stent may include, for example, an asymmetric flange design having a first retention member 102 and a second retention member 404. In another example (not shown), the stent may include a first retention member 102 but not a second retention member 104. It will be understood that any combination of the features described herein is within the scope of the present disclosure.

[0052] The embodiments described herein can have a variety of dimensions and / or characteristics suitable for a variety of purposes and / or uses with respect to a variety of tissues, for example, a stent can have a saddle region length of 5-40 mm in the deployed configuration.

[0053] In some embodiments, a saddle region of a stent in a constrained configuration, such as saddle region 106, can have a diameter in the range of 2 mm to 6 mm or 3 mm to 5 mm. For example, a stent can have a diameter D2 in a constrained configuration of 10 Fr or 3.5 mm. In some embodiments, a saddle region in a constrained configuration can have a length in the range of 40 mm to 150 mm. For example, a stent in a constrained configuration can have a length L2 in the range of 40 mm to 100 mm. In some embodiments, a stent in a constrained configuration can have a length L2 in the range of 40 mm to 80 mm.

[0054] The saddle region can have a length and a diameter. In embodiments, such as a stent having double-walled flanges as first and second retention members, the length of the saddle region can be measured as (i) the length along the elongate body between the beginning of the inwardly facing surface of each of the flanges, or (ii) the length along the body that is the shortest distance between the flanges at any point along the inwardly facing surface when the stent is expanded but not deployed in tissue, or (iii) the length along the body that is the shortest distance between the flanges at any point along the inwardly facing surface when the stent is expanded and deployed in tissue. In many embodiments, saddle regions, including those under conditions (i)-(iii) above, can have a length in the range of 5 mm to 150 mm in the expanded configuration, although in some cases, the saddle region (such as saddle region 106) can have a length in the range of 5 mm to 40 mm in the expanded configuration, or 5 mm to 20 mm in the expanded configuration. Exemplary lengths of the saddle region of a device for gastrointestinal stenting or drainage in the expanded configuration can include lengths within the range of 10 mm to 30 mm, 10 mm to 20 mm, 10 mm to 15 mm, or 5 mm to 10 mm.

[0055] In many embodiments, the diameter of the saddle region in the expanded configuration can be greater than the diameter of the elongate body in the constrained configuration. For example, the diameter of the saddle region (such as saddle region 106) in the expanded configuration can be in the range of 3 mm to 40 mm. In some embodiments, the diameter of the saddle region in the expanded configuration can be in the range of 5 mm to 25 mm, 5 mm to 20 mm, or 10 mm to 20 mm. In various embodiments, the diameter of the saddle region in the expanded configuration can be 3 to 5 times greater than the corresponding diameter of the stent in the constrained configuration, while in some embodiments, the diameter of the saddle region in the expanded configuration can be 3 to 10 times greater than the corresponding diameter of the stent in the constrained configuration.

[0056] The lumen of the saddle region in the expanded configuration, such as lumen 124 as described with respect to Figures 1A-C, can include an inner diameter of, for example, 3 to 25 mm. In embodiments, the diameter of the first and / or second retention members (such as the first and second retention members 102, 104 described with respect to FIGS. 1A-C or the retention members 402, 404 described with respect to FIG. 4) may be in the range of 5 mm to 40 mm. Other exemplary retention member diameters may be in the range of 15 mm to 40 mm or 15 mm to 35 mm. In many embodiments, the diameter of the retention members may be set to have a particular offset from the diameter of the saddle region in the expanded configuration. For example, the stent may be configured to include a difference between the diameter of the saddle region and the larger diameter of the first and / or second retention members in the expanded configuration of 3-20 mm. Some embodiments may include a difference between the outer diameter of the saddle region and the larger outer diameter of the retention members of 6-10 mm. For example, for an outer diameter of the saddle region of 10 mm, the outer diameter of the proximal and / or distal flanges may be between 16-20 mm. It will be appreciated that some embodiments may include a greater difference between the outer diameter of the saddle region and the outer diameter of the proximal and / or distal flanges. In some embodiments, such as in an esophageal stent, the difference between the outer diameter of the saddle region and the outer diameter of the proximal and / or distal flanges may be 4-6 mm. Other embodiments may include a greater and / or smaller difference between the outer diameter of the saddle region and the outer diameter of the proximal and / or distal flanges. In another example, the retention member may be configured to have a diameter 1 to 5 times greater than the diameter of the saddle region in the expanded configuration. For example, for a device having a saddle region with a diameter of 10 mm in the expanded configuration, the first retention member and / or the second retention member may have a diameter in the range of 13 mm to 30 mm, 15 mm to 25 mm, or 16 mm to 20 mm. In another example, a stent having a saddle region in the expanded configuration with a diameter of 20 mm may have one or more retention members with a diameter in the range of 23 mm to 40 mm.It will be appreciated that some embodiments may include a larger or smaller offset between the diameter of the saddle region and the larger diameter of the first retaining member and / or second retaining member.

[0057] A first retention member, such as first retention member 102, can have the same or different axial width as a second retention member, such as second retention member 104, and the axial width of a retention member can be measured as the distance along the longitudinal axis between the inward-facing surface and the outward-facing surface of the respective retention member. In some embodiments, the width of the first retention member and / or the second retention member in the expanded configuration can be in the range of 0.5 mm to 10.0 mm. In some embodiments, the width of the first and / or second retention member can be in the range of 0.5 mm to 3.0 mm. Other embodiments can include smaller and / or larger widths of the first retention member and / or the second retention member, such as in the range of 0.5 mm to 6 mm, 2 mm to 6 mm, or 3 mm to 7 mm. In some embodiments, the retention members can have a constant width. In other embodiments, the width of the retention members can vary along a vertical plane.

[0058] In some embodiments, the proximal and / or distal projection ends, such as lips 110, 112 as described with respect to Figures 1A-C, can have a length in the expanded configuration in the range of 0 mm to 3 mm, such as in the range of 0.5 mm to 2.5 mm, or in the range of 1.0 mm to 1.5 mm. The proximal and / or distal projection ends can define a lumen, such as a flange lumen, continuous with the saddle region, with a diameter equal to or greater than the lumen defined by the saddle region, or the diameter of the saddle lumen. In various embodiments, the lip or protrusion can have a flange lumen diameter in the expanded configuration that is at least 0.5-2.0 mm wider than the diameter of the corresponding saddle region in the expanded configuration, such as in the diameter range of 3.5 mm to 42 mm for a saddle diameter in the range of 3 mm to 40 mm. As another exemplary range for a corresponding saddle region diameter of 10 mm in the expanded configuration, the lip can have a diameter of 11 mm to 14 mm. For a corresponding saddle region diameter of 15 mm in the expanded configuration, the lip can have a diameter of 16-19 mm. In another example, a saddle region diameter of 20 mm in the expanded configuration can correspond to a lip diameter of 21-24 mm. The lip can be formed contiguous with the retention member and / or the saddle lumen. The lip can be parallel to the longitudinal axis of the saddle region. Alternatively, or additionally, the lip can be non-parallel to the longitudinal axis. For example, the lip can extend radially outward or inward along the longitudinal axis. A radially outward extension of the lip can promote flow through the lumen, for example, by acting as a funnel into the lumen. A radially inward extension of the lip can reduce flow through the lumen, for example, by defining a smaller inlet.

[0059] Various embodiments can include a total stent length in the expanded configuration ranging from 5 to 60 mm. For example, an exemplary deployed stent can have a length of 10 to 50 mm or 10 to 40 mm.

[0060] In various embodiments, a coil, such as coils 108, 208, 508, 608, 702 and / or 704, may be configured with a spring constant suitable for treatment of and / or placement in relation to one or more tissues or body lumens. In many embodiments, the coil may have a spring constant in the range of 50-200 N / m. It will be appreciated that a coil may have a spring constant related to its geometry, for example, related to the thickness of the coil.

[0061] All of the devices and / or methods disclosed and claimed herein can be made and performed without undue experimentation in light of the present disclosure. Although the devices and methods of the present disclosure have been described with respect to preferred embodiments, it may be apparent to those skilled in the art that variations can be applied to the devices and / or methods described herein, and in the steps or in the order of steps of the methods, without departing from the concept, spirit and scope of the present disclosure. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the present disclosure as defined by the appended claims.

Claims

1. 1. A stent comprising: an elongate body having a constraining configuration; the elongate body having an expanded configuration having a first portion expanded to become a first retention member, a second portion expanded to become a second retention member, and a saddle region defining a lumen extending between the first retention member and the second retention member; A stent, wherein the saddle region is formed of a coil configured to apply a restoring force to a tissue surface apposed to the first and second retention members, respectively.

2. 2. The stent of claim 1, wherein the first retention member comprises a first flange and a second flange configured to appose a first and second surface of a first tissue, the second retention member comprises a third flange and a fourth flange configured to appose a first and second surface of a second tissue, or both.

3. The stent of claim 1 or 2, wherein the first retention member comprises a mesh structure, the second retention member comprises a mesh structure, or both.

4. The stent of claim 1 , wherein the coil extends along the entire length of the saddle region.

5. The stent of claim 1 , wherein the coil is configured to apply tension between the first retention member and the second retention member.

6. The stent of claim 1 , wherein the coil is configured to apply a lateral outward force between the first retention member and the second retention member.

7. The stent of claim 1 , wherein the saddle region comprises two or more coils.

8. The stent of claim 7 , wherein the two or more coils are joined end-to-end.

9. 9. The stent of claim 7 or 8, wherein the two or more coils are joined at a central point.

10. 10. The stent of claim 7, wherein each of the two or more coils has a different spring constant.

11. 11. The stent of any one of claims 1 to 10, wherein the saddle region comprises at least one curve.

12. 12. The stent of claim 1, wherein the first retention member, the second retention member, and the coil are continuously formed from wire.

13. 13. The stent of any one of claims 1-12, wherein the first retention member comprises a first surface substantially perpendicular to a longitudinal axis of the saddle region, the first surface configured to appose a first tissue, the second retention member comprises a second surface substantially perpendicular to a longitudinal axis of the saddle region, the second surface configured to appose a second tissue, or both.

14. 14. The stent of any one of claims 1 to 13, wherein the coil comprises a shape memory material.

15. The stent of claim 1 , wherein the stent comprises a covering.

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