Stent for intercavitary organ bypass and stent delivery system including the stent for intercavitary organ bypass

Abstract

The present invention provides a stent for bridging hollow organs with a function of preventing displacement. The stent for bridging hollow organs (11) of the present invention is used to bridge and connect a hollow organ to another hollow organ, and comprises: a main body (12) in the shape of an elongated tube; and a main body hook (18) extending from the outer periphery of the main body (12) other than the two axial ends thereof toward the outside of the main body (12).

Description

Technical Field

[0001] The present invention relates to a stent for bridging between hollow organs and a stent delivery system for delivering the stent to a specified position in the body. Background Art

[0002] In recent years, in cases where biliary drainage is required due to unresectable malignant biliary stricture or obstruction, there have been reports of endoscopic ultrasound-guided biliary drainage (EUS-BD) being performed when access through the duodenal papilla is not possible. EUS-BD is a procedure in which an ultrasound endoscope is inserted into the stomach or duodenum, and while real-time ultrasound images are observed, the bile duct or gallbladder is punctured from the stomach wall or duodenal wall with a puncture needle, a guide wire is inserted into the bile duct or gallbladder, and a stent for bypass is inserted and indwelled in the form of a bridge between the stomach wall or duodenal wall and the bile duct or gallbladder. This procedure allows bile duct drainage to be performed by implanting a stent in the body.

[0003] As a stent used for EUS-BD, for example, a coated stent can be cited, which is formed by coating the surface of a metal stent substrate with a coating material composed of a polymer film. In addition, as a coated stent preferably used for EUS-BD, a coated stent with a hook portion that prevents displacement and damage to the visceral wall has been proposed (see Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-66221. Summary of the invention

[0007] Problem that the invention aims to solve

[0008] However, since the digestive tract such as the stomach can be greatly deformed, a stent for bridging a hollow organ to another hollow organ needs to have a further improved anti-displacement function to withstand the deformation of the hollow organ and maintain the bridging.

[0009] The present invention has been made in view of the actual situation, and an object of the present invention is to provide a stent for bridging hollow organs with an anti-displacement function and a stent delivery system including the stent.

[0010] Solutions for solving problems

[0011] In order to achieve the above-mentioned purpose, the present invention relates to a stent for bridging hollow organs, which is used to bridge and connect hollow organs with other hollow organs, and has:

[0012] a main body portion in the shape of an elongated cylinder; and

[0013] The main body hook portion protrudes from the outer periphery of the main body portion other than the two axial end portions thereof toward the outside of the main body portion.

[0014] The stent for bridging between hollow organs of the present invention can effectively prevent displacement by having the main body hook part contact the inner wall of the hollow organ to function as an anchor hook. In addition, since the main body hook part is arranged on the periphery other than the two ends of the main body part, even if the main body hook part is slightly deformed and the retention position of the main body part is deviated, a part of the main body part can be retained in the hollow organ, thereby effectively preventing the problem that the end of the stent falls off from the hollow organ.

[0015] Furthermore, for example, the main body hook portion may have a curved shape that curves toward the outside of the main body portion along a length direction from a base end portion connected to the outer periphery to a tip end portion as a free end.

[0016] Since the elastic force required to stretch the curved shape of the main body hook portion acts to resist the force that moves the stent from the indwelling position, the curved main body hook portion can effectively prevent the stent for bypassing hollow organs from being displaced or falling off from the hollow organ.

[0017] Furthermore, for example, the main body hook may be provided in plurality, and at least two of the plurality of main body hooks may be arranged at the same distance from the first end portion, which is one of the two ends.

[0018] By arranging two or more main body hooks at the same distance from the first end, the plurality of main body hooks can easily contact the inner wall of the hollow organ, thereby effectively preventing the stent for bypassing the hollow organ from being displaced or falling off from the hollow organ.

[0019] In addition, for example, there may be a plurality of independent first end hooks that are not connected to each other in the circumferential direction and have a curved shape that curves toward the outside of the main body along the length direction from the base end connected to the first end to the top end as the free end.

[0020] The stent having both the main body hook and the first end hook provided at the end of the main body can effectively prevent displacement by means of the hooks provided at multiple positions. In addition, even when the main body hook of the indwelling stent is squeezed into the body cavity side from the inner wall of the hollow organ due to deformation of the hollow organ, the first end hook provided at the first end contacts the inner wall of the hollow organ to prevent the stent from moving, and thus the stent can be effectively prevented from falling off from the hollow organ in two stages.

[0021] Furthermore, for example, the bending directions of the main body hook portion and the first end hook portion may be the same direction.

[0022] Such a stent for bypassing a hollow organ can effectively prevent the stent from falling off from the hollow organ to the body cavity side in two stages.

[0023] In addition, for example, the bending directions of the main body hook portion and the first end hook portion may be opposite to each other.

[0024] Such a stent for bypassing a hollow organ can be effectively prevented from being displaced or falling off by being placed in the body such that the wall of the hollow organ is sandwiched between the main body hook and the first end hook from both the outside and the inside.

[0025] Furthermore, for example, the main body portion may include a frame portion formed of a metal material and a covering portion formed of a polymer and covering the frame portion.

[0026] A stent whose main body has a frame portion and a covering portion is suitable for drainage and the like.

[0027] The stent delivery system according to the present invention comprises: the stent for bypassing a hollow organ as described in any one of the above; and a delivery mechanism for delivering the stent for bypassing a hollow organ to a predetermined position in the body. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a conceptual diagram showing an example of the stent delivery system according to the present invention.

[0029] Figure 2 This is an external view showing an example of the stent for bridging hollow organs according to the present invention.

[0030] Figure 3 It is along Figure 2 The cross-sectional view of the main body of the stent for interluminal organ bypass taken along line III-III is shown.

[0031] Figure 4 Yes means Figure 2 The illustrated diagram is a partial development view of a frame portion of a stent for bridging interluminal organs, a main body hook portion formed integrally with the frame portion, and a first end hook portion.

[0032] Figure 5 yes Figure 4 A partial enlarged view of a stent for bypassing hollow organs is shown.

[0033] Figure 6 This is an external view of a stent for bridging hollow organs according to a second embodiment.

[0034] Figure 7 Yes means Figure 6 The illustrated diagram is a partial development view of a frame portion of a stent for bridging interluminal organs, a main body hook portion formed integrally with the frame portion, and a first end hook portion.

[0035] Figure 8 This is an external view of a stent for bridging hollow organs according to a third embodiment.

[0036] Fig. 9 This is an external view of a stent for bridging hollow organs according to a fourth embodiment. DETAILED DESCRIPTION

[0037] Reference Figures 1 to 9 The illustrated embodiments describe the stent for bypassing a hollow organ and the stent delivery system including the stent according to the present invention.

[0038] First embodiment

[0039] Figure 1 FIG. 2 is an external view of a stent delivery system 50 according to a first embodiment of the present invention. Figure 1 (a) shows the stent delivery system 50 in a first state in which a stent 11 for bypassing a hollow organ (hereinafter, sometimes simply referred to as “stent 11”) is accommodated. Figure 1 (b) shows the distal end of the stent delivery system 50 in the second state where the stent 11 is released. In the description of the stent delivery system 50, the direction in which the stent delivery system 50 extends from the proximal end where the operating unit 60 is arranged to the distal end where the distal tip 62 is arranged is described as the axial direction D1.

[0040] like Figure 1 As shown, the stent delivery system 50 is composed of a stent 11 and a delivery mechanism 52 for delivering the stent 11 to a predetermined position in the body. The delivery mechanism 52 includes an operation portion 60, an outermost tube 64, an outer sheath 66, an inner shaft 68, and a distal tip 62. The total length of the stent delivery system 50 varies depending on the placement position of the stent 11 or the delivery path, and is, for example, about 300 to 2500 mm.

[0041] like Figure 1 As shown in (a), the stent 11 is received near the distal end of the stent delivery system 50. The operator of the stent delivery system 50 Figure 1 After the stent 11 is delivered to the indwelling position in the body in the first state shown in (a), the stent delivery system 50 is Figure 1 The second state shown in (b) is achieved, whereby the stent 11 is released and retained at a specified position in the body.

[0042] like Figure 1 (a) and Figure 1 As shown in (b), the inner shaft 68 extends in the axial direction D1 from the operating portion 60 provided at the proximal end of the stent delivery system 50 to the top end head 62 provided at the distal end of the stent delivery system 50. Figure 1In the first state shown in (a) of FIG. 8 , the inner shaft 68 is housed inside the outer sheath 66 and the housing 61 of the operation portion 60 .

[0043] like Figure 1 As shown in (b), the inner shaft 68 has a small diameter portion near the distal end that is smaller than the outer diameter of other portions. In the second state where the outer sheath 66 moves to the proximal side, the small diameter portion located at the distal end is exposed. Inside the inner shaft 68, a guide wire lumen is formed for passing a guide wire.

[0044] The distal end of the inner shaft 68 is provided with a tip 62, and a through hole communicating with the guide wire lumen of the inner shaft 68 is formed in the tip 62. The tip 62 is made of resin or the like, and has a rounded outer shape to prevent damage to the inner wall of a hollow organ when in contact with the inner wall.

[0045] The outer sheath 66 can be Figure 1 The first state shown in (a) to Figure 1 In the second state shown in (b), the outer sheath 66 moves relative to the inner shaft 68 in the axial direction D1. The proximal end of the outer sheath 66 is housed inside the housing 61 of the operating part 60. The operating part 60 is linked to the operation of the operating rod 63 installed in the housing 61, so that the outer sheath 66 moves relative to the inner shaft 68 to the proximal side in one direction of the axial direction D1. As a result, the stent delivery system 50 changes from a first state in which the outer sheath 66 covers the small diameter portion of the inner shaft 68 to a second state in which the small diameter portion of the inner shaft 68 and the stent 11 are exposed. In addition, near the operating part 60, an outermost tube 64 is provided to further cover the outer periphery of the outer sheath 66. When the operator directly grasps the outer sheath 66, the movement of the outer sheath 66 by the operating part 60 may be hindered. By covering the outer sheath 66 with the outermost tube 64, this problem can be prevented.

[0046] The outermost tube 64, the outer sheath 66, and the inner shaft 68 of the conveying mechanism 52 are composed of, for example, a flexible resin hose. In addition, a metal wire may be embedded inside the resin hose used for the outer sheath 66. In addition, a push ring 69 (see FIG. 1 ) for pushing the stent 11 in the axial direction D1 when the stent 11 is released may be provided on the proximal side of the small diameter portion of the inner shaft 68. Figure 1 (b)), the push ring 69 can be made of a material that does not transmit X-rays. In addition, the materials of the top end head 62 and the operating part 60 of the conveying mechanism 52 are not particularly limited, and for example, resin molded or processed materials can be used.

[0047] Figure 2This is an appearance diagram of the stent 11 accommodated in the stent delivery system 50, showing the state of the stent 11 in radial expansion. The stent 11 is a stent for bridging between hollow organs for bridging hollow organs with other hollow organs. It is a stent for bridging between hollow organs used in endoscopic ultrasound-guided transbiliary drainage (EUS-BD), that is, it is a stent for bridging the stomach or duodenum with the bile duct or gallbladder. In addition, the stent 11 is a self-expanding coated stent, which contracts radially due to elasticity when a compressive force is applied in the radial direction, and expands radially when the compressive force is released. However, the stent for bridging between hollow organs of the present invention is not limited to this, and may also be a balloon-expandable coated stent, or may be a stent such as a hose stent that does not expand in the radial direction.

[0048] like Figure 2 As shown, the stent 11 comprises: a main body 12, which is elongated and generally cylindrical; a main body hook 18, which protrudes from the outer periphery 12d of the main body 12 to the outside of the main body 12; a plurality of first end hooks 14 and a plurality of first end markers 16, which are arranged at one of the two ends of the main body 12, namely, the first end ( Figure 2 a plurality of second end markers 17, which are disposed at the other end of the main body portion 12, ie, the second end portion ( Figure 2 Center left end) L.

[0049] The main body portion 12 includes a cylindrical frame portion 13 and a covering portion 12 a covering the frame portion 13 . Figure 4 Yes means Figure 2 The partial expansion diagram of the frame portion 13 of the stent 11, the main body hook portion 18 formed integrally with the frame portion 13, and the first end hook portion 14 shows the state of the stent 11 when it is maximally contracted in the radial direction. Figure 4 As shown in FIG. 1 , the frame portion 13 is formed by a support unit 13a and a bridge 13b which are linear members made of metal (or resin). The frame portion 13 here may be formed by braiding wires, but is preferably formed as shown in FIG. Figure 4 As shown in the figure, the support unit 13a and the bridge body 13b are formed by laser processing or the like on a hose-shaped or tubular base material, i.e., laser cutting type. If the frame portion 13 is laser cut, when the frame portion 13 is radially expanded, the compression of the length of the frame portion 13 in the axial direction D2 is suppressed, and the stent 11 is easily retained in the desired position. The cross-sectional shape of the support unit 13a and the bridge body 13b constituting the frame portion 13 can be a quadrilateral or a circular shape. In addition, in Figure 2 and Figure 4 In the description of the stent 11 shown in FIG. 1 , the direction in which the central axis C of the cylindrical main body 12 extends is referred to as the axial direction D2 in the description of the stent 11. Figure 1As shown in FIG. 5( a ), the stent 11 is housed in the transport mechanism 52 such that the axial direction D2 of the main body 12 coincides with the axial direction D1 of the stent transport system 50 .

[0050] like Figure 2 As shown in FIG. 1 , the frame portion 13 has a plurality of support units 13a in a sawtooth annular shape and a bridge 13b connecting adjacent support units 13a. The support units 13a are connected in a circular shape in a continuous triangular wave shape along the circumference of the frame portion 13. However, as shown in FIG. Figure 4 As shown, in the state where the frame portion 14 is maximally contracted (the state after laser cutting), the support units 13a are connected in the circumferential direction while meandering in an S-shape.

[0051] like Figure 2 and Figure 4 As shown, the bridge 13b connects the apex of the triangular wave or a part of the curved portion of the meandering shape of the adjacent support unit 13a in the axial direction D2. By connecting a plurality of support units 13a in this way, a cylindrical frame portion 13 is formed. The bridges 13b connecting two adjacent support units 13a are arranged at approximately equal intervals, but the positions of the bridges 13b connecting two adjacent support units 13a are not arranged in the axial direction D2, but are staggered in the circumferential direction.

[0052] Figure 3 yes Figure 2 The cross-sectional view of the bracket 11 shown in FIG. Figure 3 As shown, the frame portion 13 is covered by the coating film 12ac of the covering portion 12, and the coating film 12ac is spread out in a manner of filling between adjacent support units 13a, covering the outer periphery of the frame portion 13. The outer periphery of the frame portion 13 covered by the coating film 12ac is further covered by the first polymer film 12aa and the second polymer film 12ab of the covering portion 12a. However, the first polymer film 12aa and the second polymer film 12ab are only Figure 2 The region other than the vicinity of the main body hook portion 18 shown covers the outer periphery of the frame portion 13 .

[0053] By filling the gaps between the adjacent struts 13a with the coating film 12ac, digestive fluids such as bile can flow inside the stent 11. In addition, by covering the frame portion 13 with the coating film 12ac, the stent inner peripheral surface 12b, which is the inner peripheral surface of the stent 11 (main body 12), can be made smooth. Since the stent inner peripheral surface 12b is made smooth, when the stent 11 is placed in the body, metabolites are less likely to accumulate on the stent inner peripheral surface 12b, thereby preventing infection and the like.

[0054] As the material of the coating film 12ac, a polymer such as an elastomer or a resin is used, among which a material that is soluble in an organic solvent and has low toxicity is preferred. As the polymer that can be used for the coating film 12ac, for example, a non-biodegradable polymer or a biodegradable polymer can be used, preferably a non-biodegradable polymer that is not easily decomposed in the body, and among the non-biodegradable polymers, polyurethane, polytetrafluoroethylene (PTFE) or silicone resin is particularly preferred. In addition, in the polymer constituting the coating film 12ac, as required, it is also possible to add additives such as anticancer agents, antithrombotic agents, and anti-aging agents.

[0055] The method of forming the coating film 12 ac on the frame portion 13 is not particularly limited, but a method of immersing the frame portion 13 in a resin solution and then drying it is preferred.

[0056] The covering portion 12a includes a first polymer film 12aa and a second polymer film 12ab that cover the outer periphery of the frame portion 13. The first polymer film 12aa is disposed between the frame portion 13 and the second polymer film 12ab, and covers the outer periphery of the frame portion 13.

[0057] The thickness of the first polymer film 12aa is preferably 4 to 20 μm as the overall average value of the first polymer film 12aa. When the first polymer film 12aa is too thick, the flexibility of the bracket 11 may be insufficient. In addition, when the first polymer film 12aa is too thin, the second polymer film 12ab may not be protected from perforation of the frame portion 13 or the like.

[0058] The first polymer film 12aa is wound around the frame portion 13 in a manner that the first polymer film 12aa is wound around the outer circumference of the frame portion 13 by more than one turn but less than one and a half turns. By making the number of turns of the first polymer film 12aa one to one and a half turns, the second polymer film 12ab can be protected from being perforated in the frame portion 13, and the lack of flexibility of the main body portion 12 can be prevented.

[0059] The second polymer film 12ab is wound around the first polymer film 12aa several times so as to surround the outer circumference of the first polymer film 12aa. By winding the second polymer film 12ab several times, it is possible to reliably prevent the digestive fluid such as bile or digested food from leaking out of the stent 11. Figure 2 In the present embodiment shown, the covering portion 12a is provided on the entire main body portion 12a, or the covering portion 12a may be provided only on a portion of the main body portion. For example, the covering portion 12a of a specified length may not be provided along the axial direction D2 from the end portion (second end portion L) on the side where the first end hook portion 14 of the main body portion 12 is not provided, but there may be an area where the main body portion 12 is constituted only by the frame portion 13.

[0060] As the material of the first polymer film 12aa and the second polymer film 12ab, a polymer such as an elastomer or a resin is used, and among these, a substance that is soluble in an organic solvent and has low toxicity is preferably used. In addition, from the viewpoint of ensuring the flexibility of the main body 12 of the stent 11 and protecting the second polymer film 12ab from the perforation of the frame part 13, as the material of the first polymer film 12aa, a polymer with higher strength than the polymer used as the material of the second polymer film 12ab is preferably used.

[0061] like Figure 2 As shown, the total length H of the main body 12 is determined by the distance between the hollow organs to be bridged, and can be set to 10 mm to 200 mm, preferably 40 mm to 120 mm. In addition, the outer diameter D of the main body 12 when expanded (when no external force is applied) is determined by the type or size of the hollow organs to be bridged, and can be set to φ2 mm to φ20 mm, preferably φ4 mm to φ15 mm, and more preferably φ6 mm to φ10 mm. The outer diameter of the main body 12 when contracted (when housed in the stent delivery system) is about a fraction of the outer diameter when expanded.

[0062] like Figure 4 As shown, the wire diameter of the support unit 13a constituting the frame portion 13 is preferably 0.05 to 1 mm. In addition, when the cross section of the support unit 13a is rectangular, the length of the cross section of the support unit 13a in the long side direction is preferably 0.06 to 1 mm, and the length in the short side direction is preferably 0.05 to 0.9 mm. The outer diameter of the frame portion 13 is substantially the same as the size of the main body portion 12.

[0063] As the material of the frame portion 13, resin or metal is used. As the resin used for the frame portion 13, a material with appropriate hardness and elasticity can be used, preferably a biocompatible resin. As the resin used for the material of the frame portion 13, for example, polyolefin, polyester, fluororesin, etc. can be cited. In addition, as a specific example of polyolefin, polyethylene terephthalate and polybutylene terephthalate can be cited. In addition, as a specific example of fluororesin, polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE), etc. can be cited.

[0064] As metals for the frame portion 13, nickel-titanium (Ni-Ti) alloys, stainless steel, tantalum, titanium, cobalt-chromium alloys, magnesium alloys, etc. can be cited, and superelastic alloys such as Ni-Ti alloys are preferred. As a specific example of a superelastic alloy for the frame portion 13, a Ni-Ti alloy containing 49 to 58% by weight of Ni can be cited. In addition, a Ni-Ti-X alloy (X = Co, Fe, Mn, Cr, V, Al, Nb, W, B, etc.) in which 0.01 to 10.0% by weight of the atoms in the Ni-Ti alloy are replaced by other atoms, or a Ni-Ti-X alloy (X = Cu, Pb, Zr) in which 0.01 to 30.0% by weight of the atoms in the Ni-Ti alloy are replaced by other atoms is preferably used as the material of the frame portion 13. The mechanical properties of these superelastic alloys are adjusted by selecting the cold working rate and / or the conditions of the final heat treatment.

[0065] The frame portion 13 can be formed by processing a hose-shaped or tube-shaped base material by laser processing using a YAG laser or the like, electrical discharge processing, chemical etching, cutting, or the like.

[0066] like Figure 2 and Figure 4 As shown, the stent 11 has a plurality of first end markers 16 and a plurality of second end markers 17. Figure 4 As shown, a plurality of first end markers 16 are in the shape of a circular plate and are integrally arranged at the first end ( Figure 4 The first end R is one of the two ends of the main body 12 (frame 13) of the stent 11. Figure 4 As shown, a plurality of second end markers 17 are in the shape of a circular plate and are integrally arranged at the second end ( Figure 4 The first marker 16 and the second marker 17 are installed on the stent 11 through a circular hole formed by a circular frame-shaped second end marker frame 17a at the left end (center end) L of the main body 12 (frame portion 13) of the stent 11. The first marker 16 and the second marker 17 are composed of, for example, X-ray contrast materials (materials that do not transmit X-rays). When the stent 11 is retained in the body, the positions of the first marker 16 and the second marker 17 are confirmed under X-ray angiography, so that the retention position of the stent 11 (the positions of the two ends of the main body 12) can be grasped.

[0067] In addition, if Figure 2As shown in FIG. 1 , the stent 11 has a plurality of main body hooks 18. The main body hooks 18 have an elongated shape extending from a base end 18b to a top end 18a. The main body hooks 18 extend outward from the outer periphery 12d other than the two axial ends R and L of the main body 12. The main body hooks 18 have a curved shape that curves toward the outside of the main body 12 along the length direction from the base end 18b connected to the outer periphery 12d to the top end 18a as a free end. However, in the stent 11 as shown in FIG. Figure 1 In the state in which the stent is contained in the stent delivery system 50 as shown in (a), as shown in the expanded view Figure 4 As shown, the main body hook portion 18 is in a stretched state in the axial direction D2. Each main body hook portion 18 is endowed with elasticity to bend toward the outside of the main body portion 12 by its own elastic force when the stent 11 is released from the stent delivery system 50.

[0068] exist Figure 4 , three main body hooks 18 are shown, and the three main body hooks 18 are integrated with the frame portion 13 made of metal material and are formed by the same tubular base material as the frame portion 13. Figure 5 yes Figure 4 The partial enlarged view shows the main hook portion 18 and the surrounding frame portion 13. Figure 5 As shown, the base end portion 18b of the main body hook portion 18 is connected to the support unit 13a of the frame portion 13 adjacent to the base end portion 18b on the side opposite to the first end portion R side, and protrudes from the support unit 13a toward the first end portion R side.

[0069] like Figure 4 As shown, at least two of the plurality of main body hooks 18 ( Figure 4 The first end R is one of the two ends of the main body 12. Figure 2 and Figure 4 As shown, all the main body hooks 18 included in the bracket 11 are arranged at the same distance W from the first end R. Different from this, the plurality of main body hooks 18 may be arranged at different distances from the first end R. The distance W from the first end R to the main body hook 18 is not particularly limited, but is preferably less than 1 / 2 of the total length H of the main body 12, and more preferably less than 1 / 4.

[0070] like Figure 2 As shown, at the first end portion ( Figure 2 The middle right end) R is provided with a plurality of first end hooks 14. Figure 4 As shown, the first end hook 14 is configured to be connected to the first end marker 16 connected to the first end R, and is formed by a linear, rod-shaped or thin plate-shaped member extending in the length direction with elasticity. Figure 2As shown, the bracket 11 has three first end hooks 14. The number of first end hooks 14 of the bracket 11 can be two or more than four, and there is no specific limitation. In addition, the first end hook 14 can also be directly connected to the first end R of the main body 12.

[0071] like Figure 2 and Figure 4 As shown, the main body 12 is connected by the support unit 13a and Figure 2 The covering portion 12a shown is connected in the circumferential direction, and oppositely, Figure 5 The plurality of first end hook portions 14 shown are not connected to each other in the circumferential direction and are independent of each other.

[0072] like Figure 2 As shown in FIG. 1 , the first end hook portion 14 has a curved shape that curves toward the outside of the main body portion 12 along the length direction from the base end portion 14b connected to the first end portion R via the first end marker 16 to the top end portion 14a as the free end. Figure 1 In the state in which the stent is contained in the stent delivery system 50 as shown in (a), as shown in the expanded view Figure 4 As shown, the first end hook portion 14 is in a stretched state in the axial direction D2. Each first end hook portion 14 is endowed with elasticity to bend toward the outside of the main body portion 12 by its own elastic force when the stent 11 is released from the stent delivery system 50.

[0073] like Figure 4 and Figure 5 As shown, in this embodiment, the first end hook portion 14 and the main body hook portion 18 are formed integrally with the frame portion 13. Therefore, the base ends 14b and 18b of the first end hook portion 14 and the main body hook portion 18 are seamlessly connected to the frame portion 13. The cross-sectional shape of the first end hook portion 14 and the main body hook portion 18 is not particularly limited, and can be rectangular or circular, or can be the same shape as the frame of the frame portion 13.

[0074] The first end hook 14 and the main body hook 18 may be formed independently of the frame 13 and fixed integrally by laser welding or the like, or may be cut out integrally with the frame 13 when the frame 13 is formed from a base material by laser processing or the like. In this case, Figure 2 The shapes (bent shapes) of the first end hook portion 14 and the main body hook portion 18 shown in the figure can be cut out of the first end hook portion 14 and the main body hook portion 18. Figure 4 and Figure 5 After the cut-out first end hook portion 14 and the main body hook portion 18 are formed into the shape shown in FIG. Figure 2 The elasticity shown is used to shape the

[0075] like Figure 4As shown in FIG. 1 , a slit extending in the length direction is formed in the middle portion 14c between the top end portion 14a and the base end portion 14b of the first end hook portion 14. The base ends 14b and 18b of the first end hook portion 14 and the main body hook portion 18 are respectively connected to the apex portion of the triangular wave of the triangular wave-shaped support unit 13a constituting the frame portion 13 (in the state where the stent 11 is maximally contracted in the radial direction). Figure 5 However, the main body hook portion 18 provided between the two ends of the main body portion 12 may also be connected to the bridge body 13b.

[0076] In order to prevent the inner wall of a hollow organ from being damaged when contacting the inner wall of the hollow organ, the top ends 14a and 18a of the first end hook 14 and the main body hook 18 are provided. Figure 4 and Figure 5 As shown, a tip protection portion having a substantially elliptical plate shape and a smooth outer surface is integrally provided. In addition, the shape of the tip protection portion can be any shape that can prevent damage to the inner wall of a hollow organ when the top ends 14a and 18a of the first end hook portion 14 and the main body hook portion 18 come into contact with the inner wall of the hollow organ, and in addition to the substantially elliptical plate shape, it can also be substantially circular plate shape or substantially semicircular plate shape. In addition, the tip protection portion may not be integrally provided with other parts of the first end hook portion 14 or the main body hook portion 18, but may be formed by attaching a substantially spherical member by post-processing.

[0077] like Figure 2 As shown, the intermediate portion 14c between the base end portion 14b and the top end portion 14a of the first end hook portion 14 is smoothly curved, and a portion of the intermediate portion 14c on the base end portion 14b side is located outside the first end portion R in the axial direction D2 of the main body portion 12 ( Figure 2 On the other hand, the other part of the middle part 14c of the first end hook 14 on the top end part 14a side or the top end part 14a is located on the inner side of the end of the bracket 11 in the axial direction D2 of the main body 12 ( Figure 2 center left).

[0078] like Figure 2 As shown in the figure, the middle parts 14c and 18c of the first end hook 14 and the main body hook 18 are formed so as to gradually move away from the central axis C of the stent 11 as they move toward the top end 14a and 18a. However, a part of the middle parts 14c and 18c of the first end hook 14 and the main body hook 18 on the top end 14a and 18a side may be formed so as to gradually move closer to the central axis C of the main body 12 as they move toward the top end 14a.

[0079] The curved shape of the first end hook portion 14 and the main body hook portion 18 may have the same curvature as a whole, or may have a curvature that changes continuously or stepwise as it moves toward the top end portion 14a, 18a. For example, the curvature of a portion of the intermediate portion 14c, 18c on the side of the base end portion 14b, 18b may be larger or smaller than the curvature of another portion on the side close to the top end portion 14a, 18a. In addition, one or more straight line portions may be provided in a portion of the curved shape of the first end hook portion 14 and the main body hook portion 18. In addition, the curved shape of the first end hook portion 14 and the main body hook portion 18 is not limited to a curve having one inflection point, but may also be a curve having two or more inflection points.

[0080] like Figure 2 As shown, the bending directions of the main body hook portion 18 and the first end hook portion 14 are in the same direction. That is, any portion of the main body hook portion 18 and the first end hook portion 14 that is bent from the outer periphery 12d of the main body portion 12 has a shape that is bent outward from the central axis C in the direction away from the center of the main body portion 12 along the axial direction D2. Such a stent 11 can be effectively prevented from falling off from the hollow organ to the body cavity side by, for example, placing both the main body hook portion 18 and the first end hook portion 14 on the hollow organ side.

[0081] As for the number and circumferential arrangement of the first end hooks 14 and the main body hooks 18, in this embodiment, there are three, and each is arranged roughly radially at equal angle intervals (i.e., 120 degrees), but the number may be two or more than four. The arrangement of the first end hooks 14 and the main body hooks 18 may be arranged at equal angle intervals, but is not limited to this, and may be selected according to the type or shape of the applicable hollow organ. In addition, in this embodiment, although the structures (curved shape, length, etc.) of the plurality of first end hooks 14 are all (three in this embodiment) consistent with each other, one or more of them may be different structures (curved shape, length, etc.). The same is true for the plurality of main body hooks 18, which may all (three in this embodiment) be consistent with each other, or one or more of them may be different structures.

[0082] like Figure 2 and Figure 4 As shown, at the second end portion ( Figure 2 and Figure 4 In the left end) L, unlike the first end R, no hook is provided. Figure 2 and Figure 4 As shown, the bracket 11 may be provided with a hook portion only at one end portion of the main body 12 , but may also be provided with hook portions at both ends of the main body 12 as in a bracket according to a fourth embodiment described later.

[0083] As described above, since the stent 11 has the main body hook portion 18 provided on the outer periphery 12d other than the two ends R and L of the main body portion 12, the first end portion R can be retained in the hollow organ even when the retention position of the main body portion 12 is slightly deviated, thereby effectively preventing the end of the stent 11 from falling off the hollow organ. In addition, in the stent 11, in addition to the main body hook portion 18, the first end hook portion 14 is provided at the first end portion R, so that even under the action of a force that attracts the first end portion R to the body cavity side relative to the stent 11, the main body hook portion 18 and the first end hook portion 14 can prevent the stent 11 from falling off the hollow organ in multiple stages.

[0084] Second embodiment

[0085] Figure 6 is an appearance diagram of a bracket 111 according to a second embodiment of the present invention. Figure 7 Yes means Figure 6 The bracket 111 shown in FIG. 1 is a partial expanded view of the frame portion 13 and the main body hook portion and the first end hook portion formed integrally therewith. The bracket 111 according to the second embodiment is different from the main body hook portion 118 in shape. Figure 2 and Figure 4 The bracket 111 is the same as the bracket 11 according to the first embodiment except for the main body hook 18 shown. Therefore, in the description of the bracket 111, the same reference numerals are used for the same points as the bracket 11, and the description thereof will be omitted.

[0086] like Figure 6 As shown, the bracket 111 has a plurality of (three in this embodiment) main body hooks 118. The main body hook 118 has an elongated shape extending from the base end 118b to the top end 118a. The main body hook 118 has a curved shape that is bent toward the outside of the main body along the length direction from the base end 118b connected to the outer periphery 12d to the top end 118a as the free end. The distance W from the first end R where the first end hook 14 is provided to the main body hook 18 is equal to Figure 2 The bracket 11 shown is the same and is less than (1 / 2) of the full length H of the main body 12 .

[0087] like Figure 6 As shown, the bending directions of the main body hook portion 118 and the first end hook portion 14 are opposite to each other. That is, the portion of the first end hook portion 14 that starts to bend from the outer periphery 12d of the main body portion 12 has a shape that is bent outward from the central axis C in the direction away from the center of the main body portion 12 along the axial direction D2. On the other hand, the portion of the main body hook portion 118 that starts to bend from the outer periphery 12d of the main body portion 12 has a shape that is bent outward from the central axis C in the direction close to the center of the main body portion 12 along the axial direction D2.

[0088] like Figure 7 As shown, the base end 118b of the main body hook portion 118 is connected to the support unit 13a of the frame portion 13 adjacent to the base end 118b on the first end R side, and protrudes from the support unit 13a to the side opposite to the first end R side.

[0089] The stent 111 involved in the second embodiment can be considered to be placed in the body for use by clamping, for example, the wall of a hollow organ from both the outside and the inside of the body hook 118 and the first end hook 14. In such a stent 111, the body hook 118 and the first end hook 14 cooperate to effectively prevent the stent 111 from being displaced toward the body cavity and the stent 111 from being displaced toward the hollow organ.

[0090] Third embodiment

[0091] Figure 8 FIG. 2 is an external view of a bracket 211 according to a third embodiment of the present invention. The bracket 211 according to the third embodiment is similar to the bracket 211 except that the shape of the main body hook 218 and the frame 213 around the main body hook 218 is the same as that of the bracket 211 according to the third embodiment. Figure 2 The bracket 211 is the same as the bracket 11 according to the first embodiment except for the main body hook portion 18 and the frame portion 13. Therefore, in the description of the bracket 211, the same reference numerals are used for the same points as the bracket 11, and the description thereof will be omitted.

[0092] The main body hook portion 218 of the bracket 211 is formed by bending a part of the support unit 13 a included in the frame portion 213 toward the outside of the main body portion 212 and exposing it from the outside of the covering portion 12 a .

[0093] Figure 8 When the frame portion 213 and the main body hook portion 218 are manufactured by laser processing or the like, the bracket 211 shown can be processed in the same shape as other frame portions that do not have the main body hook portion 218, and the productivity is excellent. In other respects, the bracket 211 involved in the third embodiment produces the same effect as the bracket 11 involved in the first embodiment. In addition, the shape of the main body hook portion of the bracket according to the present invention is not limited to the above-mentioned shape, and other shapes protruding from the outer periphery 12d can also be adopted.

[0094] Fourth embodiment

[0095] Fig. 93 is an appearance diagram of a stent 311 according to a fourth embodiment of the present invention. The stent 311 according to the fourth embodiment differs from the stent 11 according to the first embodiment in that a plurality of second end hooks 15 are provided at the second end L, and a main body hook 28 is provided at a side closer to the second end L than the center of the axial direction D2 of the main body 312. However, the main body hook 18 and the first end hook 14 are the same as those of the stent 11 according to the first embodiment, and in the description of the stent 311, the same reference numerals are attached to the same points as those of the stent 11 and the description thereof is omitted.

[0096] Although the main body hook portion 28 of the bracket 311 is different from the main body hook portion 18 in position and bending direction in the axial direction D2, it is the same as the main body hook portion 18 provided at the side closer to the first end R than the center of the axial direction D2 of the main body 312 in other respects. That is, the main body hook portion 28 is provided at a distance W from the second end L, and protrudes outward from the outer periphery 12d of the main body 312. The distance W from the second end L to the main body hook portion 28 is the same as the distance W from the first end R to the main body hook portion 18. In the cross section of the bracket 311, the area other than the vicinity of the main body hook portions 18 and 28 is the same as that of the main body hook portion 18. Figure 3 The cross section of the bracket 11 is the same as shown. In addition, in the cross section of the bracket 311, Figure 3 The first polymer film 12 aa and the second polymer film 12 ab shown cover the outer periphery of the frame portion 13 only in the area other than the vicinity of the main body hook portions 18 , 28 .

[0097] like Fig. 9 As shown, the second end hook portion 15 has a curved shape that is curved toward the outside of the main body portion 312 along the length direction from the base end portion 15b connected to the second end portion L to the top end portion 15a as the free end. The plurality of second end hook portions 15 are not connected to each other in the circumferential direction and are independent of each other. The plurality of second end hook portions 15 have the same shape and structure as the first end hook portion 14 except that they are provided at the second end portion L instead of the first end portion R, so the detailed structure of the second end hook portion 15 is omitted.

[0098] like Fig. 9 As shown, the bending directions of the main body hook portion 28 and the second end hook portion 15 are the same. That is, any portion of the main body hook portion 28 and the second end hook portion 15 that starts to bend from the outer periphery 12d of the main body portion 312 has a shape that is bent outward from the central axis C in the direction away from the center of the main body portion 12 along the axial direction D2.

[0099] In the stent 311 involved in the fourth embodiment, since the first end hook 14, the second end hook 15 and the main body hooks 18, 28 are provided on both sides of the main body 312, these hooks 14, 15, 18, 28 can prevent the two ends R, L of the main body 312 from falling off from the hollow organ in multiple stages.

[0100] Description of Reference Numerals

[0101] 11, 111, 211, 311: stents for bypassing hollow organs;

[0102] 12, 212, 312: main body;

[0103] 12a: covering part;

[0104] 12aa: first polymer film;

[0105] 12ab: second polymer film;

[0106] 12b: inner surface of the stent;

[0107] 12ac: coating film;

[0108] 12d: peripheral;

[0109] R: first end;

[0110] L: second end;

[0111] 13, 213, 313: frame part;

[0112] 13a: support unit;

[0113] 13b: bridge;

[0114] 14: first end hook portion;

[0115] 15: second end hook portion;

[0116] 16: first end marker;

[0117] 16a: first end marker frame;

[0118] 17: second end marker;

[0119] 17a: second end marker frame;

[0120] 18, 28, 118, 218: main body hook;

[0121] 14a, 15a, 18a, 118a: apical part;

[0122] 14b, 15b, 18b, 118b: base end;

[0123] 14c, 18c: middle part;

[0124] 50: stent delivery system;

[0125] 52: transport mechanism;

[0126] 60: Operation unit;

[0127] 61: Shell;

[0128] 62: top head;

[0129] 63: operating lever;

[0130] 64: outermost tube;

[0131] 66: outer sheath;

[0132] 68: inner shaft;

[0133] 69: Push ring;

[0134] D1: axial direction of the conveying system;

[0135] D2: axial direction of the main body;

[0136] C: Central axis.

Claims

1. A stent for bridging hollow organs, which is a stent used for biliary drainage under ultrasound endoscopy guidance, and is used to bridge hollow organs with other hollow organs, and has: a main body portion in the shape of an elongated cylinder; and The main body hook part protrudes from the outer periphery other than the two axial ends of the main body part toward the outside of the main body part, The stent for bridging between hollow organs further comprises a plurality of first end hooks connected to the first end, wherein the first end is one of the two ends. When the main body hook and the first end hook are both placed on the side of the hollow organ for the bridging connection, the main body hook is configured to contact the inner wall surface of the hollow organ, thereby effectively preventing the stent for bridging between hollow organs from falling off from the hollow organ to the body cavity side by means of two stages: the main body hook and the first end hook.

2. The stent for bridging hollow organs according to claim 1, characterized in that: The distance from the first end hook portion to the main body hook portion is less than 1 / 2 of the entire length of the main body portion.

3. The stent for bridging hollow organs according to claim 1 or 2, characterized in that: There are a plurality of the main body hooks, and at least two of the plurality of the main body hooks are arranged at the same distance from a first end, which is one of the two ends.

4. The stent for bridging hollow organs according to claim 1 or 2, wherein: The first end hook has a curved shape that curves toward the outside of the main body along the length direction from the base end connected to the first end to the tip end as the free end. The plurality of first end hooks are not connected to each other in the circumferential direction and are independent of each other.

5. The stent for bridging hollow organs according to claim 4, characterized in that: The main body hook portion and the first end hook portion are bent in the same direction.

6. The stent for bridging hollow organs according to claim 1 or 2, characterized in that: The main body has a frame portion made of a metal material and a covering portion made of a polymer and covering the frame portion.

7. A stent delivery system, comprising: The stent for bridging hollow organs according to any one of claims 1 to 6; and A transport mechanism transports the hollow organ bypass stent to a predetermined position in the body.

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