High retention drainage device

Abstract

The present disclosure relates generally to the field of medical devices. In particular, the present disclosure relates to medical devices, such as stents, for facilitating the flow of fluids and materials among and / or between adjacent body lumens, which maintain an open flow path between the body lumens. In one example, the stent can include an elongate body configured to be expandable between a first constrained configuration and a second unconstrained configuration. In the unconstrained configuration, the body can have a first retention member, a second retention member, and a cylindrical saddle region defining a lumen extending along a longitudinal axis between the first and second retention members. The first retention member or the second retention member, or both, can include a double-walled flange having an axially inward wall and an axially outward wall, a portion of the inward wall being curved along the longitudinal axis toward a vertical center plane of the saddle region.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 005,936, filed April 6, 2020, pursuant to 35 U.SC §119, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to the field of medical devices. In particular, this disclosure relates to medical devices, such as stents, for facilitating the flow of fluids and materials between adjacent body cavities, which maintain open flow pathways between or within body cavities. Background Technology

[0004] The placement of self-expanding stents (e.g., self-expanding metallic stents or SEMS) within anatomical regions (e.g., body cavities, access routes, blood vessels, tubes, etc.) allows for fluid communication from one region to another. For example, a stent can allow for the flow of material from one body cavity to another.

[0005] However, existing stents can have various drawbacks. For example, stents are more likely to shift or migrate from the desired location, such as in response to forces generated by patient movement; or they may not provide sufficient holding force or provide too much holding force for a given purpose.

[0006] Therefore, a variety of beneficial medical outcomes can be achieved through the apparatus and / or methods disclosed herein. Summary of the Invention

[0007] In one aspect, the support may include an elongated body configured to expand between a first constrained configuration and a second unconstrained configuration. The elongated body in the unconstrained configuration may include a first retaining member, a second retaining member, and a cylindrical saddle-shaped region extending along a longitudinal axis between the first and second retaining members. The cylindrical saddle-shaped region may define a lumen extending along the longitudinal axis. The first or second retaining member, or both, may include a double-walled flange having an axially inner wall, an axially outer wall, and a radially outermost edge extending between the axially inner and outer walls. At least a portion of the inner wall may be bent along the longitudinal axis toward the vertical central plane of the cylindrical saddle-shaped region.

[0008] In accordance with the description and other aspects of this disclosure, the inward and outward walls of the first retaining member or the second retaining member, or both, may include non-parallel surfaces. At least a portion of the outward wall may be curved along the longitudinal axis away from the vertical central plane of the cylindrical saddle region. The outward wall may include a concave portion curved along the longitudinal axis away from the vertical central plane of the cylindrical saddle region. The inward or outward wall, or both, may include straight edges. The inward wall may include a convex portion curved along the longitudinal axis away from the vertical central plane of the cylindrical saddle region. The outward wall may include a convex portion curved along the longitudinal axis toward the vertical central plane of the cylindrical saddle region. The axially outermost end of the first retaining member or the axially outermost end of the second retaining member, or both, may extend into a lip away from the vertical central plane of the cylindrical saddle region. The lip may define a lumen for a double-walled flange. The flange lumen may be continuous with the lumen of the cylindrical saddle region. The lip may include the inner diameter of the flange lumen, which is equal to or wider than the inner diameter of the cylindrical saddle-shaped region lumen. The radially outermost edge may include a diameter greater than the diameter of the cylindrical saddle-shaped region. The radially outermost edge may include a cylindrical portion parallel to the longitudinal axis. The internal radius of curvature between the inner wall and the radially outermost edge may be greater than, equal to, or less than the internal radius of curvature between the radially outermost edge and the outer wall. The radially outermost edge may be offset from a vertical plane along the longitudinal axis between the starting point of the inner wall and the ending point of the outer wall. The elongated body may include a braid composed of one or more wires. The support may include a circumferential cover that extends entirely or partially along the length of the elongated body.

[0009] In one aspect, the support may include a tubular structure having a constrained form and an expanded form. The expanded tubular structure may include a first end, a second end, and a central region, the first end expanding into a first double-walled flange, the second end expanding into a second double-walled flange, and the central region extending along a longitudinal axis between the first and second ends. The central region may define a lumen extending along the longitudinal axis. The first double-walled flange or the second double-walled flange, or both, may include an axially inward wall and an axially outward wall. At least a portion of the inward wall may be bent along the longitudinal axis toward a vertical central plane of the central region. The cross-sectional profile of the first double-walled flange or the second double-walled flange, or both, along a plane parallel to the longitudinal axis may be asymmetrical.

[0010] In accordance with the description and other aspects of this disclosure, the inward and outward walls of the first retaining member or the second retaining member, or both, may include non-parallel surfaces. The inward wall may include a first curved portion that bends along a longitudinal axis toward a vertical central plane of the central region; the inward wall may include a second curved portion that bends along a longitudinal axis away from a vertical central plane of the central region; or the inward wall may include both the first and second curved portions. The inward or outward wall, or both, may include straight edges.

[0011] In one aspect, the support may include a cylindrical body having a constrained form and an expanded form. In the expanded form, the cylindrical body may include a first retaining member, a second retaining member, and a saddle-shaped region extending along a longitudinal axis between the first and second retaining members. The saddle-shaped region may define a lumen extending along the longitudinal axis. The first or second retaining member, or both, may include a double-walled flange including an axially inward wall and an axially outward wall. At least a portion of the inward wall may be bent along the longitudinal axis toward a vertical central plane of the saddle-shaped region. The inward and outward walls of the first or second retaining member, or both, may include non-parallel surfaces.

[0012] In the description and other aspects of this disclosure, the inward wall may include a first curved portion that bends along a longitudinal axis toward the vertical center plane of the saddle-shaped region; the inward wall may include a second curved portion that bends along a longitudinal axis away from the vertical center plane of the saddle-shaped region; or the inward wall may include both the first and second curved portions. In the foregoing and other aspects of this disclosure, the same or different inward and outward wall features may be applied to the double-walled flanges of the first retaining member, the second retaining member, or both. That is, the support according to aspects of this disclosure may have double-walled flanges on either or both of the first and second retaining members, and the axially inward and outward walls of the flanges may be constructed similarly or distinctly relative to the two retaining members. Attached Figure Description

[0013] Non-limiting examples of this disclosure are described with reference to the accompanying drawings, which are schematic and not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown is generally indicated by a single reference numeral. For clarity, not every component is labeled in every drawing, and every component of each embodiment of this disclosure is not shown where illustration is not essential to allowing those skilled in the art to understand this disclosure. In the drawings:

[0014] Figure 1 A side view of a medical device is shown according to one or more embodiments described herein;

[0015] Figure 2A cross-sectional view of a medical device is shown according to one or more embodiments described herein;

[0016] Figures 3A to 3F Alternative retaining member configurations are shown according to the various embodiments described herein;

[0017] Figure 4 The delivery aspect of a medical device is illustrated according to one or more embodiments described herein.

[0018] Figure 5 One or more embodiments described herein illustrate a medical device disposed in an organ. Detailed Implementation

[0019] This disclosure is not limited to the specific embodiments described. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope beyond the appended claims. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0020] While embodiments of this disclosure are specifically described with reference to medical devices (e.g., stents, etc.) and systems for drainage of the gallbladder, pseudocysts, and / or gastrojejunostomies, it should be understood that such medical devices can be used in a variety of medical procedures (e.g., bile efflux conversion, enteroenterostomy, gastroduodenostomy, and gastroenterostomy, etc.) to establish and / or maintain temporary or permanent open flow or drainage pathways from or between various body organs, lumens, catheters, blood vessels, fistulas, cysts, and spaces (e.g., dermis, stomach, duodenum, jejunum, small intestine, gallbladder, kidney, pancreas, biliary / pancreatic tree, bladder, ureter, abscess, wall-bound pancreatic necrosis (WOPN), bile ducts, etc.). These devices can be inserted via various access points and methods, such as percutaneously, endoscopically, laparoscopically, or combinations thereof. The medical devices disclosed herein are self-expanding, but in other embodiments, the medical devices may be expandable in other ways, including, for example, balloon catheters. Furthermore, such medical devices are not limited to drainage, but can facilitate access to organs, blood vessels, or body cavities for other purposes, such as creating pathways to divert or bypass fluids or solids from one location to another, removing obstructions, and / or delivering therapies, including non-invasive or minimally invasive manipulation of tissues within organs and / or the introduction of pharmacological agents via open flow pathways.

[0021] As used herein, the singular forms “a,” “an,” and “the” are intended to also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” or “containing” and / or “having,” when used herein, specify the presence of the stated feature, region, step, element, and / or component, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and / or groups thereof.

[0022] As used herein, the term "distal" refers to the end of the device that is furthest from the healthcare professional when the device is introduced into the patient, while the term "proximal" refers to the end of the device that is closest to the healthcare professional when the device is introduced into the patient.

[0023] In embodiments, this disclosure relates to a medical device (e.g., a self-expanding metallic stent and / or a duodenal expulsion device, etc.) configured to extend between first and second body cavities and facilitate the adsorption or maintenance of adsorption of corresponding layers (e.g., muscle layers) of each cavity to establish a temporary, long-term, or permanent open flow or access pathway therebetween. As described herein, one or both of the first and second retaining members (such as flanges) at opposite ends of the stent may be double-walled and include one or more non-perpendicular surfaces of axially inward and axially outward walls of the flanges oriented relative to a cylindrical saddle-shaped region extending longitudinally between the flanges. This configuration of non-perpendicular surfaces reduces the migration of the medical device relative to tissue between the first and second body cavities compared to, for example, a corresponding retaining member having only a vertical surface. Alternatively, a retaining member having one or more non-perpendicular double-walled flanges can be configured to provide more control over the resistance of the device when pulled away from a predetermined position after deployment, for example, generating a higher pull-out force compared to a corresponding retaining member with a vertical surface. For example, a double-walled flange with a non-perpendicular surface can have a pull-out force higher than 4N, 4.5N, 5N, 5.25N, 5.5N, 5.75N, or 6N, such as pull-out forces of 4.1N, 4.2N, 4.3N, 4.4N, 4.5N, 4.6N, 4.7N, 4.8N, 4.9N, 5.0N, 5.1N, 5.2N, 5.3N, 5.4N, 5.5N, 5.6N, 5.7N, 5.75N, 5.8N, 5.9N, 6.0N, 6.1N, 6.2N, 6... 0.3N, 6.4N, 6.5N, 6.6N, 6.7N, 6.8N, 6.9N, 7.0N, 7.1N, 7.2N, 7.3N, 7.4N, 7.5N, 7.6N, 7.7N, 7.8N, 7.9N, 8.0N, 8.1N, 8.2N, 8.3N, 8.4N, 8.5N, 8.6N, 8.7N, 8.8N, 8.9N, or 9.0N. In various embodiments, one or more non-perpendicular surfaces may also be configured to interact less with at least one tissue wall trauma of the first and second body cavities (e.g., configured as inward tissue contact points with a smaller surface area) compared to, for example, a vertical surface or another surface (which has at least one tissue engagement element, such as forks, barbs, hooks, or other similar designs).

[0024] The non-perpendicular surfaces of a medical device (such as a support with retaining members comprising axially inward and outward walls of a double-walled flange) may include one or more curved portions, straight portions, angled portions, or any combination thereof; wherein each portion may include equal or unequal lengths, angles, internal radii of curvature, orientation, internal angles, or other characteristics relative to another portion. The surfaces of the first and second retaining members may be identical or different. For example, each end of the medical device may be designed to improve the strength of the medical device (e.g., resistance to pull-off or retaining strength, or resistance to radial compression or radial strength) and provide a desired amount of linear fit force when placed across a tissue plane. The flange shape may include one or more rolls and / or structural folds, for example, to create a double-walled flange structure. In various embodiments, the flange shape may include multiple inflection points, wherein the inflection points may be curve points where changes in curvature direction occur.

[0025] Medical devices (such as stents) may be formed from one or more filaments and / or surfaces. In various embodiments, one or more metal wires, braids consisting of one or more wires, polymer filaments, sheets, or combinations thereof may form the medical device. For example, the length of a braid consisting of one or more wires may form the medical device. The medical device may include one or more structural elements, such as struts, hoops, meshes, grid cells, or other units. In many embodiments, the medical device may include meshes, braids, and / or knitted surfaces. In various embodiments, the medical device may be formed from shape memory materials, such as nitinol.

[0026] Various embodiments of the medical device described herein may include complete or partial coverings, coatings, or other membranes (extending between structural elements) on the interior or exterior of the device, or any combination thereof. For example, coverings, coatings, or other membranes may include silicones, polymers, or combinations thereof. For example, coverings may include polyurethane, polytetrafluoroethylene, expanded polytetrafluoroethylene, polyvinylidene fluoride, aromatic polycarbonate-based thermoplastic polyurethane, and / or other similar materials. Coverings may be applied by dip coating, roller coating, brush coating, spray coating, other known application methods, or combinations thereof. Coverings, coatings, or other membranes may inhibit tissue growth and / or minimize fluid leakage from inside and / or outside the medical device.

[0027] Covers, coatings, or other films may extend completely or partially over the medical device. For example, a first retaining member, a second retaining member, a saddle-shaped region (extending between the first and second retaining members), or combinations thereof may include solid covers, porous covers, or other constructed covers. In some embodiments, such as a stent having a cylindrical saddle-shaped region and double-walled flanges as first and second retaining members, a circumferential cover or coating may be suitable to cover the entire length of the stent or a portion of its length. For example, a partial coating may cover the entire length of the saddle-shaped region but not the flanges. Embodiments are not limited herein.

[0028] The various embodiments described herein may include one or more additional features designed to engage at least one tissue layer. For example, embodiments may include one or more textured surfaces, forks, or other tissue engagement elements along a first retaining member, a second retaining member, or any combination thereof.

[0029] refer to Figure 1 In one embodiment, the stent of this disclosure may include an elongated body or tubular structure 110, the elongated body or tubular member 110 forming a lumen and including a first portion, a second portion, a length, and a diameter. The elongated body 10 may be covered, uncovered, or a combination of covered and uncovered. The elongated body 110 may include a constrained form (e.g., an unexpanded or delivery form; not shown) and an expanded or unconstrained form (e.g., a forward shortening or unfolding form, such as...). Figure 1 (As shown). The elongated body can be configured to be expandable between a constrained and unconstrained configuration. In the unconstrained configuration, a first portion 112 of the elongated body can expand radially into a first retaining member 114, and a distal portion 122 of the elongated body can expand radially into a second retaining member 124. In some embodiments, the elongated body 110 in the constrained configuration may have a diameter in the containment range of 2 mm to 6 mm or 3 mm to 5 mm. For example, the support may have a constrained configuration diameter of 10 Fr or 3.5 mm. In some embodiments, the elongated body 110 in the constrained configuration may have a length in the containment range of 40 mm to 150 mm. For example, the support in the constrained configuration may have a length in the containment range of 40 mm to 100 mm. In some embodiments, the support in the constrained configuration may have a length in the containment range of 40 mm to 80 mm.

[0030] The central region can extend along the longitudinal axis of the support between the retaining members. For example, as Figure 1As shown, the central region may include a cylindrical saddle-shaped region 128 extending between the first retaining member 114 and the second retaining member 124 along the longitudinal axis of the support. The cylindrical saddle-shaped region 128 may include a tubular structure or cylindrical body defining or otherwise including a lumen or similar structure extending through it along the longitudinal axis. The cylindrical saddle-shaped region 128 may include a length and a diameter. In embodiments, a stent, such as one having double-walled flanges as first and second retaining members, includes an axially inner wall and an axially outer wall, wherein a portion of the inner wall bends toward the vertical central plane of the stent. The length of the cylindrical saddle region can be measured as (i) the length along the elongated body between the origins of the inner wall of each flange, or (ii) the length along the body of the shortest distance between the flanges at any point along the inner wall when the stent expands but does not unfold into the tissue, or (iii) the length along the body of the shortest distance between the flanges at any point along the inner wall when the stent expands and unfolds into the tissue. In many embodiments, the cylindrical saddle region including conditions (i)-(iii) above can have a length in the expansion configuration that is within the containment range of 5 mm to 150 mm, but in some cases, the cylindrical saddle region (such as...) Figures 1 to 2 Region 128) in the expanded form may have a length within a containment range of 5 mm to 35 mm. Exemplary lengths of the cylindrical saddle-shaped region of the expanded form for a gastrointestinal stent or drainage device may include lengths within a containment range of 10 mm to 30 mm, 15 mm to 20 mm, 10 mm to 20 mm, 10 mm to 15 mm, or 5 mm to 10 mm.

[0031] In many embodiments, the diameter of the cylindrical saddle-shaped region in the expanded state may be larger than the diameter of the elongated body in the constrained state. For example, the cylindrical saddle-shaped region in the expanded state (such as...) Figures 1 to 2 The diameter of region 128 can be within a range of 3 mm to 40 mm. In some embodiments, the diameter of the cylindrical saddle-shaped region 128 in the expanded form can be within a range of 5 mm to 25 mm, 5 mm to 20 mm, 5 mm to 15 mm, or 10 mm to 20 mm, for example, 5 mm, 10 mm, 15 mm, or 20 mm. In various embodiments, the diameter of the cylindrical saddle-shaped region 128 in the expanded form can be 3 to 5 times larger than the corresponding diameter of the support in the constrained form; however, in some embodiments, the diameter of the cylindrical saddle-shaped region 128 in the expanded form can be 3 to 10 times larger than the corresponding diameter of the support in the constrained form.

[0032] Refer again Figures 1 to 2The first retaining member 114 and the second retaining member 124 may extend radially outward from the outer circumference of the elongated body 110 in its expanded state to define a double-walled flange together with corresponding inner wall surfaces 114a, 114b, 124a, and 124b. For example, the inner wall surface 114a may be the axial inner wall of the first flange, the outer wall surface 114b may be the axial outer wall of the first flange, the inner wall surface 124a may be the axial inner wall of the second flange, and the outer wall surface 124b may be the axial outer wall of the second flange. A radially outermost edge 114c may extend between and connect the inner wall surfaces 114a and 114b. A radially outermost edge 124c may extend between and connect the inner wall surfaces 124a and 124b. The radially outermost edge may be offset along the longitudinal axis from a vertical plane or from the center point of a distance extending between the starting point of the retaining member's inner wall surface and the ending point of its outer wall surface, the distance extending between the cylindrical saddle-shaped region and the final protrusion or lip. The radially outermost edge may include a diameter larger than the diameter of the cylindrical saddle-shaped region. In various embodiments, the radially outermost edge may define the diameter of the corresponding retaining member.

[0033] In the embodiments, the first retaining member and / or the second retaining member (such as...) Figures 1 to 2 The diameter of the retaining members (114, 124) may be within a range of 5 mm to 40 mm. Other exemplary retaining member diameters may be within a range of 15 mm to 40 mm or 15 mm to 35 mm. In many embodiments, the diameter of the retaining member may be set to have a specific offset from the diameter of the cylindrical saddle region in the expanded form. For example, the support may be configured to include a difference of 3 mm to 20 mm between the diameter of the cylindrical saddle region and the diameter of the first and / or second retaining members in the expanded form. In other instances, the first and / or second retaining members may be configured to have a diameter that is 1 to 5 times larger than the diameter of the cylindrical saddle region in the expanded form. For example, for a device having a cylindrical saddle region with a diameter of 10 mm in the expanded form, the first and / or second retaining members may have diameters within a range of 13 mm to 30 mm, 15 mm to 25 mm, or 16 mm to 20 mm. In another example, a support having a cylindrical saddle-shaped region with a diameter of 20 mm in an expanded configuration may have one or more retaining members having a diameter within the containment range of 23 mm to 40 mm. It should be understood that some embodiments may include a larger or smaller offset between the diameter of the cylindrical saddle-shaped region and the larger diameter of the first retaining member and / or the second retaining member.

[0034] Refer again Figures 1 to 2The first retaining member 114 may have the same or different axial width as the second retaining member 124, wherein the axial width of the retaining member can be measured as the distance along the longitudinal axis between the inner and outer walls of the respective retaining member (including the radially outermost edge). In some embodiments, the width of the first retaining member 114 and / or the second retaining member 124 in the expanded configuration may be within an envelope range of 0.5 mm to 10.0 mm. Other embodiments may include smaller and / or larger widths of the first retaining member and / or the second retaining member, such as within an envelope range of 0.5 mm to 6 mm, 2 mm to 6 mm, or 3 mm to 7 mm. In some embodiments, the retaining member may have a constant width. In other embodiments, the width of the retaining member may vary along a vertical plane.

[0035] like Figures 1 to 2As shown, the outer wall surface 114b of the first retaining member 114 may extend substantially along the longitudinal axis away from the vertical central plane of the cylindrical saddle-shaped region 128 into the protrusion 116 or lip, the protrusion 116 or lip being located at the axial outermost end of the first retaining member 114 of the elongated body 110. The outer wall surface 124b of the second retaining member 124 may extend substantially along the longitudinal axis away from the vertical central plane of the cylindrical saddle-shaped region 128 into the protrusion 126 or lip, the protrusion 126 or lip being located at the axial outermost end of the first retaining member 114 of the elongated body 110. In some embodiments, the protrusion 116 and / or the protrusion 126 may have a length in an expanded form within a containment range of 0 to 3 mm, such as within a containment range of 0.5 mm to 2.5 mm or 1.0 mm to 1.5 mm. Protrusions 116 and / or 126 may define lumens, such as flange lumens continuous with a cylindrical saddle region, wherein the diameter is greater than or equal to the diameter of the lumen or saddle lumen defined by the cylindrical saddle region 128. In various embodiments, the lip or protrusion may include an expanded flange lumen diameter that is at least 0.5 mm to 2.0 mm wider than the diameter of the corresponding cylindrical saddle region 128 in the expanded form. For example, for a saddle diameter in a containment range of 3 mm to 40 mm, the expanded flange lumen diameter is in a containment range of 3.5 mm to 42 mm. As another exemplary containment range, for a corresponding cylindrical saddle region diameter of 10 mm in the expanded form, the lip may have a diameter of 11 mm to 14 mm. For a corresponding cylindrical saddle region diameter of 15 mm in the expanded form, the lip may have a diameter of 16 mm to 19 mm. In another example, the 20mm diameter of the cylindrical saddle-shaped region in its expanded form may correspond to a lip diameter of 21mm to 24mm. Protrusions 116 and / or 126 may be continuously formed with retaining members 114, 124 and the saddle-shaped lumen 128. Protrusions 116 and / or 126 may be parallel to the longitudinal axis of the cylindrical saddle-shaped region. Alternatively or additionally, protrusions 116 and / or 126 may not be parallel to the longitudinal axis. For example, protrusions 116 and / or 126 may extend radially outward or inward along the longitudinal axis. The radially outward extensions of protrusions 116 and / or 126 may facilitate flow through their lumen, for example, by acting as a funnel to the lumen. The radially inward extensions of protrusions 116 and / or 126 may impede flow through their lumen, for example, by defining their smaller inlets.

[0036] Various embodiments may include an overall support length in the range of 5 mm to 60 mm in an expanded configuration. For example, an exemplary deployed support may have a length of 10 mm to 50 mm or 10 mm to 35 mm.

[0037] In various embodiments, the angles of the retaining member relative to the circumference and longitudinal axis of the elongated body can be of various degrees, or the degree of orientation can be changed along the axial direction of the retaining member inward and / or outward (compared to a retaining member with a vertical wall), thereby creating inflection points on the wall of the retaining member. For example, as with Figure 2 As shown in the cross-sectional view of the support, the outer wall surface 114b and / or the outer wall surface 124b may include at least a portion of an axially outward wall that extends or bends away from the vertical center plane 202 or midline of the longitudinal axis of the cylindrical saddle-shaped region 128. Additionally or alternatively, the outer wall surface 114b and / or the outer wall surface 124b may include at least a portion of an axially outward wall that extends or bends toward the vertical center plane 202. Similarly, the inner wall surface 114a and / or the inner wall surface 124a may include at least a portion of an axially inward wall that extends or bends away from the vertical center plane 202 of the longitudinal axis of the cylindrical saddle-shaped region 128. Additionally or alternatively, the inner wall surface 114a and / or the inner wall surface 124a may include at least a portion of an axially inward wall that extends or bends toward the vertical center plane 202. In various embodiments, the inward wall surface 114a and the outward wall surface 114b of retaining member 114 may be non-parallel to each other, and / or the inward wall surface 124a and the outward wall surface 124b of retaining member 124 may include surfaces that are non-parallel to each other.

[0038] The lumen 204 may extend through the longitudinal length of the cylindrical saddle-shaped region 128. The saddle-shaped region lumen 204 may include dimensions suitable for different purposes, such as those described above.

[0039] refer to Figure 2 One or more components shown may include those relative to Figure 1 One or more aspects that are similar to the corresponding structures shown and / or described. For example, Figure 2 The slender body of the support can be relative to Figure 1 The elongated body 110 described is similar to or the same as the one described.

[0040] Although Figures 1 to 2 A support is shown that includes both a first retaining member and a second retaining member having a double-walled flange structure, but it should be understood that the support may include only one of the first or second retaining members. Additionally or alternatively, the support may include a first retaining member and / or a second retaining member with alternative configurations, such as an expanded geometry, a funnel, a blocking element, a widening structure, or another configuration for facilitating flow through the support.

[0041] The protrusion 116 in its expanded state defines a first protrusion lumen 206, which may have a diameter at least as large as the diameter of the lumen 204. The protrusion 126 in its expanded state defines a second protrusion lumen 208, which may have a diameter at least as large as the diameter of the lumen 204. The diameter of the first protrusion lumen 206 may be the same as or different from the diameter of the second protrusion lumen 208. For example, an exemplary diameter of the first protrusion lumen 206 may be defined by an exemplary diameter of the first protrusion 116, such as relative to... Figure 1 The exemplary diameter of the second protrusion lumen 208 described herein can be defined by the exemplary diameter of the second protrusion 126, such as relative to... Figure 1 As described; or both. (Combined with the above) Figure 1 The various dimensions outlined in the bracket (e.g., constraint-mode length and diameter, expansion-mode overall bracket length, saddle region length and diameter, retaining member width and diameter, and protrusion length) are applicable. Figure 2 The bracket, and is applicable to any bracket with a retaining member construction, as described below relative to... Figures 3A to 3F As described.

[0042] Figures 3A to 3F An alternative configuration of the cross-sectional profile of a double-walled flange structure is shown, which serves as a second retaining member 124 in an expanded configuration. Regarding... Figures 3A to 3F In each of these, the cylindrical saddle-shaped region 128 is described as extending from the left side of the illustration into the retaining member 124. The retaining member 124 is described as extending from the right side of the illustration into the protrusion 126.

[0043] As relative to Figures 3A to 3F The construction of the described flange structure can be applied to any of the embodiments described herein. For example, as relative to Figure 1 The first retaining member 114 described, as relative to Figure 1 The described second retaining member 124 or both may have, as relative to Figures 3A to 3F The described construction. Therefore, embodiments may include multiple retaining members having the same or different constructions. For example, the first retaining member 114 may include, as described... Figure 3A The configuration shown, and the second retaining member 124 may include, as shown in the diagram. Figure 3C The constructions shown are valid. Any combination of the described constructions is within the scope of this disclosure.

[0044] Alternatively or additionally, various embodiments may include one of the first retaining member 114 or the second retaining member 124, and alternative configurations at opposite ends. For example, various embodiments may include alternative configurations such as a flange, flared retaining member, spherical retaining member, inclined retaining member, coiled retaining member, folded retaining member, or another configuration (not shown) having a flange perpendicular to the wall of the respective cylindrical saddle region 128. Some embodiments may include one or more components for managing the flow of material through it. For example, various embodiments may include a valve, a barrier member, a funnel, a pipe, or other structures that can be used to manage the flow through it.

[0045] In various embodiments of the medical device, the inner wall surface of the retaining member, the outer wall surface of the retaining member, or at least a portion thereof may include at least one curved surface, a straight surface, an angle, an inner radial circumference, an outer radial circumference, a surface extending or curved toward a vertical central plane of a cylindrical saddle region or central region of the medical device, a surface extending or curved away from a vertical central plane of a saddle or central region of the medical device, a surface perpendicular to the longitudinal axis of the cylindrical saddle region, a surface parallel to the longitudinal axis of the cylindrical saddle region, or any combination thereof.

[0046] The inner and outer wall surfaces of a component may include non-parallel surfaces, such as those obtained by means of... Figures 3A to 3F The example is illustrated in this manner. In various embodiments, the retaining member may include asymmetric inward and outward wall surfaces. For example, the cross-sectional profile of the first retaining member 114 or the second retaining member 124, or both, may be asymmetric along the longitudinal axis of the cylindrical saddle region 128. In some embodiments, the asymmetric wall surfaces may each have a shape and / or strength, such as retaining strength, which may be adapted to interact with tissues in accordance with appropriate geometry and / or mechanical features.

[0047] The retaining member having a portion retaining the maximum outer diameter may include a radially outermost edge that may connect, join, and / or extend between the inward and outward wall surfaces of the retaining member. For example, the radially outermost edge (e.g., Figures 1 to 3F 124c) may include a ridge line along the curved confluence of the inner wall surface 124a and the outer wall surface 124b, such as in Figure 3B In the middle; or the outermost radial edge may include one or more portions parallel to the longitudinal axis of the cylindrical saddle-shaped region 128, such as in Figure 3A , Figure 3C , Figure 3D and Figure 3E In the middle. The outermost radial edge 124c may or may not be centered above the length along the longitudinal axis, which lies between the starting point of the inner wall surface of the retaining member and the ending point of the outer wall surface.

[0048] In various embodiments, at least a portion of the retaining member may include a concave surface, such as... Figure 3A The outer wall surface 124b is shown. In some embodiments, the concave surface or portion of the retaining member may be located away from the vertical center plane of the cylindrical saddle-shaped region along the longitudinal axis (e.g., Figure 2 The vertical center plane 202) is bent. In various embodiments, at least a portion of the retaining member may include a convex surface, for example, as... Figure 3A The inner wall surface 124a is shown. In some embodiments, the convex surface or portion of the retaining member may be oriented along the longitudinal axis toward the vertical center plane of the cylindrical saddle-shaped region (e.g., Figure 2 The vertical center plane 202) is bent. The inward and / or outward wall surfaces of the corresponding first and second retaining members, in any combination thereof (having a configuration including portions not perpendicular to the cylindrical saddle region), can increase the resistance of the corresponding retaining member to deformation, thereby increasing the pull-off strength of the retaining member relative to the flange, which includes only the surface perpendicular to the longitudinal axis of the cylindrical saddle region. Furthermore or alternatively, the inward wall surface can engage and maintain the adhesion of the tissue wall with less trauma relative to the tissue wall and with greater resistance to movement compared to the corresponding surface perpendicular to the cylindrical saddle region. Therefore, the support with retaining members according to embodiments of this disclosure can withstand less migration compared to the corresponding surface perpendicular to the cylindrical saddle region.

[0049] For example, such as Figure 3A As shown, the elongated body can extend from the cylindrical saddle-shaped region 128 into the retaining member. Although Figure 3A The second retaining member 124 is shown as a double-walled flange structure; however, it should be understood that the first retaining member 114 may include... Figure 3A The configuration is shown. For example, the first retaining member 114 may include a corresponding double-walled flange structure. Alternatively, either the first retaining member 114 or the second retaining member 124 may include an alternative configuration.

[0050] refer to Figure 3AThe cylindrical saddle-shaped region 128 may extend into an inner wall surface 124a, which in this example includes three portions: portion 302a, portion 302b, and portion 302c. The cylindrical saddle-shaped region 128 may extend into the concave surface of portion 302a, and portion 302a may extend into portion 302b. Portion 302b includes a straight edge extending toward the vertical center plane (not shown) of the cylindrical saddle-shaped region at an angle of less than 90 degrees. In some embodiments, the inner wall surface may extend toward its vertical center plane along the longitudinal axis of the cylindrical saddle-shaped region by a distance of 0.0 mm to 5.0 mm. For example, portion 302b may extend toward the vertical center plane of the cylindrical saddle-shaped region 128 by 0.5 mm to 1.5 mm. However, in other embodiments consistent with this disclosure, the inner wall surface may extend toward its vertical center plane along the longitudinal axis of the cylindrical saddle-shaped region by a greater distance. Part 302c includes a convex curve extending between part 302b and the radially outermost edge 124c. The radially outermost edge 124c may include a portion parallel to the surface of the cylindrical saddle-shaped region 128. The radially outermost edge 124c may extend into the outer wall surface 124b, which in... Figure 3A Examples may include portions 304a and 304b. Portion 304a may include a convex surface. In various embodiments, the internal radius of curvature between the inner wall surface and the radially outermost edge may be greater than the internal radius of curvature between the radially outermost edge and the outer wall. For example, as... Figure 3A As shown, portion 302b may have a larger inner circumferential radius than portion 304a. However, it should be understood that alternative embodiments may include different relative circumferential radii between these portions. Portion 304a may extend into portion 304b, and portion 304b may include a concave surface. Portion 304b may extend into protrusion 126, as described elsewhere herein. One or more convex and / or concave surfaces may include the same or different curvature finish angles, circumferential radii, lengths, other features, or any combination thereof.

[0051] about Figure 3B The example embodiment shown may include similar portions 302a, 302b, and 302c, as relative to... Figure 3A As described. However, as Figure 3B The portion 304a shown may include, for example, Figure 3A The larger radius of curvature shown. Figure 3B In this configuration, portion 304a may include a radius of curvature that varies along its length. In some embodiments, portion 304a or other portions may include non-uniform and / or other undulating curves. Figure 3B As shown, part 304b may include a concave portion.

[0052] Figure 3CAnother exemplary embodiment is shown, wherein the retaining member may include similar portions 302a, 302b, and 302c, as relative to Figure 3A and / or Figure 3B As described. However, as Figure 3C The portion 304a shown may include, for example, Figure 3A The larger radius of curvature shown. Figure 3C In this portion, portion 304b may include a straight edge extending back from the radially outermost edge 124c and portion 304a toward the cylindrical saddle-shaped region 128. Portion 304b may extend into portion 304c, where portion 304c... Figure 3C The portion 304c is shown as including a concave portion. The portion 304c may extend into the protrusion 126. In many embodiments, the angle pointing outwards from the second retaining member 124 and defined by the portion 304b and the protrusion 126, or the angle of the portion 304c, may be less than 90 degrees.

[0053] Another exemplary embodiment is shown in Figure 3D In. Figure 3D In this configuration, portion 302a may include a concave curve extending into the straight edge of portion 302b. Portion 302b may extend into the convex curve of portion 302c, which in turn extends into the radially outermost edge 124c. The radially outermost edge 124c may extend into portion 304a, which may include a convex curve. Portion 304a may extend into the straight edge of portion 304b, which in turn extends into portion 304c, which may include a concave segment. Portion 304c may extend into the protrusion 126. However, compared to the concave curve portion 304c in FIG. 3c, one or more portions 302a, 302c, 304a, and / or 304c may include a smaller radius of curvature, for example, as... Figure 3D The concave curve portion 304c is shown in the figure. In some embodiments, at least a portion of the concave or convex curve may include a sufficiently tight radius of curvature to include folds or other folds.

[0054] Figure 3E Another exemplary embodiment is shown, wherein portions 302a, 302b, 302c, 304a and / or 304b may include relative to Figures 3A to 3D One or more similar parts of at least one of the corresponding parts described in the text. However, in Figure 3E In the middle, the curves for parts of 304a and parts of 304b include those for... Figure 3A The curves of parts 304a and 304b have smaller radii of curvature.

[0055] Figure 3FAnother exemplary embodiment is shown, wherein the retaining member may include similar portions 302a, 302b, and 302c, as relative to Figures 3A to 3E As described by at least one of them. Figure 3F The portion 302a shown may include, compared to, as Figure 3A The larger radius of curvature shown. For example, parts (such as, such as) Figure 3F The portion 302a) shown may include a radius of curvature of 1 mm to 3 mm. In some embodiments, portions 302a and / or 302c may include a radius of curvature of 1.5 mm to 2.1 mm. Figure 3F In this context, portion 302a may include a radius of curvature that varies along its length. For example... Figure 3F As shown, portion 302a may extend or sink into a radius narrower than the corresponding cylindrical saddle-shaped region 128. Portion 302d may extend between the cylindrical saddle-shaped region 128 and portion 302a, or portion 302d may be considered as an extension of the cylindrical saddle-shaped region leading to the starting point of portion 302a and the starting point towards the inner wall surface 124a. In some embodiments, portion 302a or other portions may include non-uniform and / or other undulating curves. Figure 3F As shown, portion 304b may include a straight portion perpendicular to the longitudinal axis of the cylindrical saddle-shaped region 128. Portion 304c may include a concave surface extending into the protrusion 126. Portions may include sufficiently small radii of curvature to form right angles or relative right angles. For example, portions (such as...) Figure 3F The portion shown (304c) may include a radius of curvature of 0.0 mm to 0.5 mm (e.g., 0.1 mm to 0.3 mm).

[0056] Although each part is relative to Figures 3A to 3F While described, it should be understood that various embodiments may include one or more similar and / or different portions from the illustrated examples. For example, the inner wall surface 114a, the outer wall surface 114b, the inner wall surface 124a, and / or the outer wall surface 124b may include more or fewer portions, and any portion may include at least one concave segment, a convex segment, a straight edge, or any combination thereof. Portions may extend toward the first or second end of the device, perpendicular to the surface of the cylindrical saddle region, parallel to the surface of the cylindrical saddle region, at another angle relative to the surface of the cylindrical saddle region, or any combination thereof. Furthermore, relative to... Figures 3A to 3F The dimensions and / or orientation of any of the described portions may be applied to other portions described together, alternatively or in combination, or otherwise applied to portions within the scope of this disclosure and / or to maintain the component outline.

[0057] In some embodiments, a smaller radius of curvature of the portion can promote higher retaining strength of the corresponding retaining member. For example, Figure 3E The structure shown is compared to Figure 3A The corresponding construction may allow for greater resistance to deformation of the second retaining member 124. Therefore, embodiments can be constructed to meet various retaining member strength requirements, such as those required by at least one specific regulation, organization, or other considerations.

[0058] Figure 4 Aspects of delivery methods for medical devices as described herein are illustrated by way of examples.

[0059] The medical device can be disposed in a constrained configuration between the inner member 402 and the outer sheath 404 of the tissue puncture element. For example, in the constrained configuration, one or more of the first retaining member 114, the second retaining member 124, or the cylindrical saddle-shaped region 128 can be limited to a smaller outer diameter compared to those features in the expanded or unconstrained configurations, such as relative to... Figure 1 As described in Figure 3, a sharpened end 416 of the tissue puncture element may be included to advance from the first body cavity 412 through the tissue layer 410. The sharpened end 416 of the tissue puncture element may be advanced through the tissue layer 406 and into the second body cavity 408. Additionally or alternatively, the tissue puncture element may include a conductive end for advancement through the tissue layers 410 and / or 406. In various embodiments, a gap space 414 may exist between the tissue layers 410 and 406 prior to the deployment of a medical device (e.g., a stent).

[0060] As the end of the tissue-piercing element advances through the tissue layer 406, the outer sheath 404 can retract proximally relative to the inner member 402, or the inner member 402 can extend distally relative to the outer sheath 404, thereby allowing the distal end of the medical device to move from a constrained to an unconstrained state. In particular, the distal end of the medical device can expand into the second retaining member 124.

[0061] The medical device can be positioned such that a portion of the inner wall surface 124a of the second retaining member 124 contacts the tissue layer 406. The tissue puncture element can retract proximally through the tissue layer 406, such that the second retaining member 124 is held in the second body cavity 408. The tissue puncture element can retract proximally through the tissue layer 410 (not shown).

[0062] After the second retaining member is deployed, the medical device, together with the inner member and the outer sheath, may retract proximally a predetermined distance, for example, by a visual (e.g., colored band) and / or imagerable (e.g., radiopaque) marking on the device, such that the first retaining member remains constrained between them and does not deploy prematurely (e.g., deployed into the gap space 414). Once the second (or in this case, distal) retaining member 124 is deployed, the action of retracting the complete assembly proximally may also act to pull the tissue layers 410, 406 into contact or further into contact with each other. When the device retracts sufficiently to clear the tissue layer 410, the outer sheath 404 may retract proximally relative to the inner member 402, or the inner member 402 may extend distally relative to the outer sheath 404, thereby allowing the proximal end of the medical device to move from a constrained to an unconstrained state. In particular, the proximal end of the medical device may expand into the first retaining member 114.

[0063] Figure 5 A cross-section of the fully delivered stent of this disclosure is shown. For example, Figure 5 The support can be as relative to Figures 1 to 4 The stent described herein. Various components of the stent may be similar to those described above. The stent may be located within a patient's body such that the inward wall surface 114a of the first retaining member 114 contacts the tissue wall 506, and the outward wall surface 124a of the second retaining member 124 contacts the tissue wall 508, wherein a cylindrical saddle-shaped region 128 extends between them. The adherent tissue layers may be walls of the same or different tissues. For example, tissue wall 506 may correspond to tissue layer 410, and tissue wall 508 may correspond to tissue layer 406, as relative to... Figure 4 As described. In some embodiments, the first retaining member 114 and the second retaining member 124 may contact the tissue wall 506 of the first tissue and the tissue wall 508 of the second tissue, such that the first tissue and the second tissue interact at the tissue interface. In some embodiments, the first retaining member 114 and the second retaining member 124 may interact with the tissue wall 506 and the tissue wall 508 to cause the respective tissue walls to interact at the interface to close the space therebetween and / or shorten its width. For example, as relative to Figure 4The width of the described gap space 414 may be reduced or eliminated. In some embodiments, at least one additional tissue (not shown) may be located between the tissue of the first tissue wall 506 and the tissue of the second tissue wall 508. Thus, a lumen extending through the first retaining member 114, the second retaining member 124, and the cylindrical saddle region 128 provides an open internal passage between the first body cavity 502 and the second body cavity 504. The stent may partially or completely cover, for example, to prevent fluid draining from the second body cavity to the first body cavity from leaking into the gap space between the tissue walls through the retaining members and / or the saddle region of the stent.

[0064] As relative to Figure 5 As exemplarily described, the stent can be disposed in a constrained configuration between the inner member and the outer sheath of the tissue-piercing element. For example, in the constrained configuration, one or more of the first retaining member 114, the second retaining member 124, or the cylindrical saddle region 128 can be constrained to a smaller outer diameter. The sharpened end of the tissue-piercing element can be advanced through the tissue wall and into the second body cavity 504. Additionally or alternatively, the tissue-piercing element may include a conductive end for advancement through the tissue wall. The distal portion 516 of the stent can then be advanced distally beyond the lumen of the tissue-piercing element such that the second retaining member 124 is disposed within the second body cavity 504 and positioned toward the inner wall surface 124a to contact the tissue wall 508. The tissue-piercing element can then be retracted proximally together with the proximal end of the constrained stent such that the proximal portion of the stent is disposed proximally on the tissue wall 506. Then, the proximal portion 518 of the stent may be disposed in the first body cavity 502 such that the first retaining member 114 is released from the sheath and expands within the first body cavity 502, wherein the inner wall surface 114a contacts the tissue wall 506.

[0065] Alternatively, in the above method, an independent instrument with a sharpened tip can be advanced along the path described above and into the second body cavity 504, 408 to create a path, a guidewire is placed in place and the independent instrument is withdrawn via the guidewire, and a stent according to the various embodiments described above is loaded onto the delivery catheter and then deployed according to the steps outlined above, the delivery catheter being inserted via the guidewire.

[0066] According to this disclosure, all the apparatuses and / or methods disclosed and claimed herein can be made and performed without extensive experimentation. Although the apparatuses and methods of this disclosure have been described according to preferred embodiments, it will be apparent to those skilled in the art that variations may be applied to the apparatuses and / or methods described herein, as well as the steps or sequence of steps of the methods, without departing from the spirit and scope of this disclosure. All such similar alternatives and modifications that are apparent to those skilled in the art are considered to be within the spirit, scope, and concept of this disclosure as defined by the appended claims.

Claims

1. A stent, comprising: An elongated body, wherein the elongated body is configured to be expandable between a first constrained state and a second unconstrained state. The elongated body in the second unconstrained configuration includes a first retaining member, a second retaining member, and a cylindrical saddle-shaped region. The first retaining member extends radially outward from the elongated body, the second retaining member extends radially outward from the elongated body, and the cylindrical saddle-shaped region defines a lumen extending along a longitudinal axis between the first and second retaining members. Wherein, the first retaining member or the second retaining member, or both, includes a double-walled flange, the double-walled flange having an axially inner wall, an axially outer wall spaced apart from the axially inner wall, and a radially outermost edge extending between the axially inner wall and the axially outer wall, and Wherein, at least a portion of the axially inner wall of at least one of the first retaining member or the second retaining member bends along the longitudinal axis and transversely to the longitudinal axis toward the vertical center plane of the cylindrical saddle region, such that the radially outer portion of the at least a portion of the axially inner wall is closer to the vertical center plane than its radially inner portion.

2. The stent according to claim 1, wherein, The inward and outward walls of the first retaining member, the second retaining member, or both include non-parallel surfaces.

3. The stent according to claim 2, wherein, At least a portion of the outer wall bends along the longitudinal axis away from the vertical center plane of the cylindrical saddle region.

4. The stent according to claim 3, wherein, The outer wall includes a concave portion that bends along the longitudinal axis away from the vertical center plane of the cylindrical saddle region.

5. The stent according to claim 1, wherein, The inner wall or the outer wall, or both, includes straight edges.

6. The stent according to claim 1, wherein, The inner wall includes a convex portion that bends along the longitudinal axis away from the vertical center plane of the cylindrical saddle-shaped region.

7. The stent according to claim 1, wherein, The outer wall includes a convex portion that bends along the longitudinal axis toward the vertical center plane of the cylindrical saddle-shaped region.

8. The stent according to claim 1, wherein, The outermost axial end of the first retaining member or the outermost axial end of the second retaining member, or both, extends from the vertical center plane of the cylindrical saddle region into a lip, the lip defining the lumen of the double-walled flange, the flange lumen being continuous with the lumen of the cylindrical saddle region.

9. The stent according to claim 8, wherein, The lip includes an inner diameter that is equal to or wider than the inner diameter of the cylindrical saddle-shaped region lumen.

10. The stent according to claim 1, wherein, The outermost radial edge includes a diameter that is larger than the diameter of the cylindrical saddle-shaped region.

11. The stent according to claim 10, wherein, The outermost radial edge includes a cylindrical portion parallel to the longitudinal axis.

12. The stent according to claim 1, wherein, The internal radius of curvature between the inner wall and the outermost radial edge is greater than the internal radius of curvature between the outermost radial edge and the outer wall.

13. The stent according to claim 1, wherein, The elongated body comprises a braid composed of one or more threads.

14. The support according to claim 1, further comprising a circumferential cover that extends entirely or partially along the length of the elongated body.

15. A stent, comprising: A tubular structure having a constrained form and an expanded form, wherein the expanded form of the tubular structure includes a first end, a second end, and a central region; the first end expands into a first double-walled flange, the second end expands into a second double-walled flange, and the central region defines a cavity extending along a longitudinal axis between the first end and the second end. Wherein, the first double-walled flange or the second double-walled flange, or both, includes an axially inner wall and an axially outer wall. At least a portion of the axially inner wall is curved along the longitudinal axis and transversely to the vertical center plane toward the central region, such that the radially outer portion of the at least a portion of the axially inner wall is closer to the vertical center plane than its radially inner portion. The cross-sectional profile of the first double-walled flange, the second double-walled flange, or both along a plane parallel to the longitudinal axis is asymmetrical.

16. The stent according to claim 15, wherein, The axially inner wall and the axially outer wall of the first double-walled flange, or the second double-walled flange, or both, include non-parallel surfaces.

17. The stent according to claim 15, wherein, The inner wall includes: A first curved portion, the first curved portion bending along the longitudinal axis toward the vertical center plane of the central region; and The second curved portion bends along the longitudinal axis away from the vertical center plane of the central region.

18. The stent according to claim 15, wherein, The inner wall or the outer wall, or both, includes straight edges.

19. A stent, comprising: A cylindrical body having a constrained form and an expanded form, wherein, in the expanded form, the cylindrical body includes: A first retaining member, a second retaining member, and a saddle-shaped region defining a lumen extending along a longitudinal axis between the first and second retaining members. Wherein, the first retaining member or the second retaining member, or both, includes a double-walled flange, the double-walled flange including an axially inner wall and an axially outer wall, at least a portion of the axially inner wall being curved along the longitudinal axis and transversely to the longitudinal axis toward the vertical center plane of the saddle-shaped region, such that the radially outer portion of the at least a portion of the axially inner wall is closer to the vertical center plane than its radially inner portion, and Wherein, the inner wall and the outer wall of the first retaining member or the second retaining member or both include non-parallel surfaces.

20. The stent according to claim 19, wherein, The inner wall includes: A first curved portion, the first curved portion bending along the longitudinal axis toward the vertical center plane of the saddle-shaped region; and The second curved portion bends along the longitudinal axis away from the vertical center plane of the saddle-shaped region.

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