Tube stent

Abstract

To provide a tube stent capable of achieving an appropriate open state with a simple configuration, which has an excellent migration prevention effect, especially when a tissue wall of a digestive organ where the tube stent is indwelled is thin.SOLUTION: A tube stent 1 consisting of a flexible tube member is composed of a straight body part 11 having roughly a linear shape and a pair of tail parts 21 and 31 communicated with the two ends of the straight body part 11 respectively, at least part of which has a curved shape. The pair of tail parts 21 and 31 include contact parts 22 and 32 respectively that come in contact with a tissue wall of a digestive organ, and a separation distance in an axial direction of the straight body part 11 between the contact parts 22 and 32 is 3 cm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tube stent that is placed in digestive tissue such as the digestive tract to allow fluid to pass through the wall of the digestive tissue. [Background technology]

[0002] Conventionally, drainage (stent placement) has been commonly performed by placing a tube stent through an endoscope to drain fluid from a body cavity. As tube stents used in stent placement, tube stents formed into various shapes are known, as disclosed in Patent Documents 1 and 2 below, for example.

[0003] Patent Document 1 discloses a stent having a generally tubular body with a lumen defined therethrough. The stent body has a proximal portion with a curved portion configured to be placed proximal to the sphincter. The stent body further includes a distal portion having a retention member extending outward from the proximal end. The retention member is configured to be placed distal to the sphincter and engage with the sphincter.

[0004] Patent Document 2 discloses a plurality of tube stents each having a stent arc portion, at least one end of which is formed of at least a portion of an arc.

[0005] As typified by Patent Documents 1 and 2, pigtail-type stents, in which at least one or both of the stent ends are curved into a pigtail shape, are known as conventional tube stents. In conventional general pigtail-type stents, the pigtail shape of the stent ends has a migration (movement) prevention effect that prevents the stent from shifting position or falling off. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2013-521868 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-8862 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in conventional pigtail stents, the distance between both ends of the pigtail-shaped stent is set to about 5 to 15 cm. Although conventional pigtail stents have the function of preventing the stent ends from shifting or falling off, there is a problem that the placement of the stent becomes unstable, such as the stent moving in the penetration direction or the stent ends moving, particularly when the wall of the digestive tissue in which the tubular stent is placed is thin.

[0008] In view of the above problems, the present invention aims to provide a tube stent that has a simple configuration, achieves an appropriate patency state, and has excellent migration prevention effects, particularly when the digestive tissue wall in which the tube stent is placed is thin. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the tube stent of the present invention is a tube stent made of a flexible tubular member, and is composed of a straight body portion having an approximately linear shape and a pair of tail portions each connected to both ends of the straight body portion and having at least a partially curved shape, wherein the pair of tail portions each have a contact portion that contacts the wall of digestive tissue, and the distance between the contact portions in the axial direction of the straight body portion is 3 cm or less.

[0010] With this configuration, the contact portions of the pair of tail portions located at both ends of the tubular stent come into contact with the digestive tissue wall so as to sandwich the wall, thereby restricting the movement of the tubular stent and improving the migration prevention effect, particularly when the digestive tissue wall in which the tubular stent is placed is thin.Furthermore, with this configuration, when the pair of tail portions are placed in different digestive tissues, the different digestive tissues can be brought into close proximity with each other, and adhesion between the different digestive tissue walls can also be promoted.

[0011] In the tube stent according to the present invention, the pair of tail portions may be curved such that the contact portions face each other in the axial direction of the straight body portion.

[0012] This configuration allows the contact portion to clamp the same location on the digestive tissue wall, thereby further improving the migration prevention effect and also improving the effect of bringing different digestive tissues closer together and causing them to adhere to each other.

[0013] In the tube stent according to the present invention, the surfaces formed by the curved shapes of the pair of tail portions may be substantially flush with each other.

[0014] This configuration allows the contact portion to clamp the same location on the digestive tissue wall, thereby further improving the migration prevention effect and also improving the effect of bringing different digestive tissues closer together and causing them to adhere to each other.

[0015] The tube stent according to the present invention may have one or more side holes provided on a side surface of at least one of the pair of tail portions.

[0016] This configuration increases the amount of fluid flowing in and out of the tube stent, improving the drainage effect of the tube stent.

[0017] In the tube stent according to the present invention, the one or more side holes may be provided on a side surface of the tail portion that is arranged on the upstream side of the fluid flowing inside the tube stent.

[0018] This configuration allows the fluid to flow efficiently into the tube stent, significantly improving the drainage effect of the tube stent.

[0019] The tube stent according to the present invention may be provided with an extension portion on the open end side of at least one of the pair of tail portions, which extends the tube structure of the tube stent.

[0020] This configuration makes it possible to use the extension portion to stabilize the tube stent and to use the extension portion to improve the drainage effect of the tube stent.

[0021] The tube stent according to the present invention may have one or more side holes provided on the side surface of the extension portion.

[0022] This configuration makes it possible to improve the efficiency of fluid inflow and outflow in the tube stent and increase the amount of fluid, thereby significantly improving the drainage effect of the tube stent.

[0023] In the tube stent according to the present invention, the contact portion of at least one of the pair of tail portions may extend in a substantially straight line along the wall of the digestive tissue.

[0024] This configuration increases the area over which at least one of the contact portions of the pair of tail portions comes into contact with the wall of digestive tissue, thereby further improving the effect of preventing migration and also improving the effect of bringing different digestive tissues closer together and causing them to adhere to each other.

[0025] In the tube stent according to the present invention, the contact portions of both of the pair of tail portions may extend substantially linearly along the wall of the digestive tissue.

[0026] This configuration increases the area over which both contact portions of the pair of tail portions come into contact with the wall of digestive tissue, thereby further improving the effect of preventing migration and also improving the effect of bringing different digestive tissues closer together and causing them to adhere to each other.

[0027] In the tube stent according to the present invention, at least one of the pair of tail portions may be curved around the axis of the straight body portion.

[0028] This configuration increases the area over which at least one of the contact portions of the pair of tail portions comes into contact with the wall of digestive tissue, thereby further improving the effect of preventing migration and also improving the effect of bringing different digestive tissues closer together and causing them to adhere to each other.

[0029] In the tube stent according to the present invention, both of the pair of tail portions may be curved around the axis of the straight body portion.

[0030] This configuration increases the area over which both contact portions of the pair of tail portions come into contact with the wall of digestive tissue, thereby further improving the migration prevention effect and also improving the effect of bringing different digestive tissues closer together and causing them to adhere to each other. [Effects of the Invention]

[0031] According to the present invention, it is possible to provide a tube stent that has a simple configuration, achieves an appropriate patency state, and has an excellent migration prevention effect, particularly when the wall of the digestive tissue in which the tube stent is placed is thin. [Brief explanation of the drawings]

[0032] [Figure 1]FIG. 1 is a perspective view showing an example of a tube stent according to an embodiment of the present invention. [Figure 2] 1 is a plan view showing an example of a tube stent delivery device for placing a tube stent in a bile duct in an embodiment of the present invention. FIG. [Figure 3] FIG. 3 is a plan view showing the inner catheter of the tube stent delivery device shown in FIG. 2. [Figure 4] FIG. 3 is a plan view showing the outer catheter of the tube stent delivery device shown in FIG. 2. [Figure 5] 1 is a schematic diagram showing a state in which a tube stent according to an embodiment of the present invention is placed to connect the gallbladder and the duodenum. FIG. [Figure 6] FIG. 1 is a schematic diagram showing in more detail the state in which a tube stent according to an embodiment of the present invention is placed to connect the gallbladder and the duodenum. [Figure 7] FIG. 7 is a schematic diagram showing the state after the tube stent shown in FIG. 6 has been removed. [Figure 8] FIG. 1 is a perspective view showing a first derivative example of a tube stent according to an embodiment of the present invention. [Figure 9] FIG. 10 is a perspective view showing a second derivative example of a tube stent according to an embodiment of the present invention. [Figure 10] FIG. 10 is a perspective view showing a third derivative example of a tube stent according to an embodiment of the present invention. [Figure 11] FIG. 10 is a perspective view showing a fourth derivative example of a tube stent according to an embodiment of the present invention. [Figure 12] FIG. 10 is a perspective view showing a fifth derivative example of a tube stent according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, a tube stent according to an embodiment of the present invention will be described with reference to the drawings. do.

[0034] The tube stent of the present invention is placed in digestive tissue, such as the digestive tract, so as to penetrate a relatively thin wall of the digestive tissue to allow fluid (liquid or gas) to pass through the wall. For example, the tube stent of the present invention can be used as a stent that connects the gallbladder and duodenum to allow bile to pass when the bile duct or cystic duct is clogged due to bile duct stones or gallbladder stones, a stent that connects a pancreatic cyst formed in the pancreas to the stomach to allow fluid within the pancreatic cyst to pass to the stomach, a stent that connects the abdominal cavity and stomach to drain ascites accumulated in the abdominal cavity to the stomach, or a stent that connects the stomach and duodenum to decompress the stomach and allow fluid to pass from the stomach to the duodenum when the stomach or duodenum is obstructed or narrowed. The tube stent of the present invention can be used for drainage, such as to drain or reduce pressure in the body.

[0035] Fig. 1 is a perspective view showing an example of a tube stent according to an embodiment of the present invention. The tube stent 1 shown in Fig. 1 is made of a flexible tubular member made of a resin such as polyethylene. The tube stent 1 is produced by molding and processing the tubular member into a predetermined shape, and has a configuration in which a pair of tail portions 21, 31 are connected via a straight body portion 11. More specifically, the tube stent 1 shown in Fig. 1 is generally configured to include a straight body portion 11 having a substantially linear shape and a pair of tail portions 21, 31 each connected to both ends of the straight body portion 11 and having at least a partially curved shape.

[0036] In the following, the axial direction of the straight body portion 11 may be referred to as the longitudinal direction of the tube stent 1. In the following, the tail portion 21 is positioned upstream and the tail portion 31 is positioned downstream, based on the flow direction of the fluid that flows through the tube stent 1 when placed in the body. For example, if the tube stent 1 is a stent that connects the gallbladder and duodenum to allow bile to circulate, the tail portion 21 is positioned in the gallbladder (upstream of the bile) and the tail portion 31 is positioned in the duodenum (downstream of the bile).

[0037] The straight body portion 11 is a central portion of the tube stent 1 that extends in the longitudinal direction of a flexible tubular member that constitutes the tube stent 1. The straight body portion 11 has a substantially linear shape.

[0038] A substantially linear shape means that the shape is substantially linear in a natural state where no external load is applied, and more specifically, for example, means that the approximate central axis of the lumen inside the tube member is substantially linear.

[0039] When the tube stent 1 is placed in the body, the straight body portion 11 is positioned so as to penetrate the wall of the digestive tissue, which is the wall surface of the digestive tissue. For example, when the tube stent 1 is a stent connecting the gallbladder and the duodenum, the straight body portion 11 is positioned so as to penetrate the gallbladder wall and the duodenal wall.

[0040] The tail portions 21, 31 are each located at the end of a flexible tubular member that constitutes the tube stent 1. The tail portions 21, 31 are formed so that at least a portion thereof is curved, and may be formed, for example, into a shape known as a pigtail or alpha loop. The size of the tail portions 21, 31 is not particularly limited, but the outer diameter of the annulus formed by the tail portions 21, 31 is usually about 1 cm.

[0041] The curved shape indicates that the tube is curved in its natural state without any external load, and more specifically, indicates that, for example, the approximate central axis of the lumen inside the tube member is curved.

[0042] The tail portions 21, 31 may be curved at approximately the same curvature (approximately a perfect circle), or may be curved only partially or partially at different curvatures. In the tube stent 1 shown in Fig. 1, the tail portions 21, 31 are formed in the same shape symmetrical with respect to the straight body portion 11, but the tail portions 21, 31 may have different shapes.

[0043] In the tube stent 1 shown in FIG. 1, the surfaces formed by the curved shapes of the tail sections 21, 31 (surfaces including the arcs formed by the middle parts of the tail sections 21, 31; hereinafter referred to as loop surfaces) are configured to be included in approximately a plane. However, the curved shape (spiral shape) may also be formed by moving the tube member in a direction perpendicular to the loop surface. Furthermore, in the tube stent 1 shown in FIG. 1, the tail sections 21, 31 are wound so as to be symmetrical with respect to the straight body section 11, and the loop surfaces of the tail sections 21, 31 are configured to be approximately on the same plane. However, the loop surfaces of the tail sections 21, 31 may also be configured to be on different planes.

[0044] The tail portions 21, 31 are curved back toward the body portion 11. At least a portion of the tail portion 21 is preferably located closer to the center of the body portion 11 in the axial direction of the body portion 11 than a connection position P1 with the body portion 11 (the end of the body portion 11 on the tail portion 21 side). Similarly, at least a portion of the tail portion 31 is preferably located closer to the center of the body portion 11 in the axial direction of the body portion 11 than a connection position P2 with the body portion 11 (the end of the body portion 11 on the tail portion 31 side).

[0045] The tail portions 21, 31 have contact portions 22, 32, respectively, in regions (shaded regions in FIG. 1) located toward the center of the straight body portion 11 of the tail portions 21, 31. When the tube stent 1 is placed inside the body, the tail portions 21, 31 are positioned on either side of the digestive tissue wall, and the contact portions 22, 32, located inside the tail portions 21, 31, are in contact with the digestive tissue wall.

[0046] The contact portions 22 and 32 are configured to be adjacent to each other in a natural state where no external load is applied. Specifically, the separation distance D between the contact portions 22 and 32 in the axial direction of the body portion 11 is set to be 3 cm or less in a natural state where no external load is applied.

[0047] The distance D between the contact portions 22, 32 may be set appropriately depending on the application of the tube stent 1. For example, when the tube stent 1 of this embodiment is used as a stent connecting the gallbladder and the duodenum, the tail portions 21, 31 are positioned so that the gallbladder wall and the duodenal wall are sandwiched between them. The gallbladder wall and the duodenal wall are relatively thin, and the distance D between the contact portions 22, 32 may be set to 2 to 3 mm or less. Furthermore, when the tube stent 1 of this embodiment is used as a stent connecting a pancreatic cyst and the stomach, a stent connecting the abdominal cavity and the stomach, or a stent connecting the stomach and the duodenum, the distance D between the contact portions 22, 32 may be set to 1 cm or less to match the thickness of the stomach wall, which is up to approximately 1 cm.

[0048] The separation distance D between the contact portions 22 and 32 may be set so that they contact each other in a natural state without an external load (i.e., so that the separation distance D is zero). Furthermore, in a natural state without an external load, the tail portions 21 and 31 may cross each other, with the contact portion 22 of the tail portion 21 positioned closer to the connection position P2 (the end of the body portion 11 closer to the tail portion 31) than the contact portion 32 of the tail portion 31, and the contact portion 32 of the tail portion 31 positioned closer to the connection position P1 (the end of the body portion 11 closer to the tail portion 21) than the contact portion 22 of the tail portion 21. When the tail portions 21 and 31 cross each other, the separation distance D between the contact portions 22 and 32 is preferably 1 cm or less. Note that the state in which the tail portions 21 and 31 cross each other can be expressed as a negative separation distance D, and a preferred range for the separation distance D in this embodiment can be expressed as being greater than or equal to −1 cm and less than or equal to 3 cm.

[0049] Tail portion 21 and tail portion 31 are pre-curved at least partially. In a natural state where no external load is applied, contact portion 22 of tail portion 21 and contact portion 32 of tail portion 31 are separated by a distance D, but if this distance D changes, an elastic force acts to return them to their original state where they are separated by the distance D.

[0050] In the tube stent 1 shown in FIG. 1, the tail portions 21 and 31 are curved (wound) in the same direction, and the loop surfaces of the tail portions 21 and 31 are configured to be substantially flush with each other. As a result, the contact portions 22 and 32 of the tail portions 21 and 31 are positioned so that they face each other in the axial direction of the straight body portion 11. By positioning the contact portions 22 and 32 in opposing positions, when the tube stent 1 is placed in the body, the contact portions 22 and 32 can sandwich the same location on both sides of the digestive tissue wall, further improving the migration prevention effect and also improving the effects of bringing different digestive tissues closer together and adhering the digestive tissue walls. However, the contact portions 22 and 32 do not necessarily have to be positioned in opposing positions. Even in this case, the migration prevention effect, the effects of bringing different digestive tissues closer together, and the effects of adhering the digestive tissue walls can be obtained.

[0051] One end of the tail portions 21, 31 is connected to connection positions P1, P2, which are the ends of the straight body portion 11, while the other end of the tail portions 21, 31 is an open end 23, 33 that opens into the lumen inside the tubular member. When the tube stent 1 is placed in the body, the open ends 23, 33 of the tail portions 21, 31 serve as an inlet and outlet for fluid, allowing fluid to circulate through the lumen of the tubular member.

[0052] The tail portions 21, 31 may be provided with one or more side holes 24, 34. The side holes 24, 34 provided in the tail portions 21, 31 are through-holes that penetrate the tube wall of the tubular member. There are no particular limitations on the positions or number of the side holes 24, 34 provided in the tail portions 21, 31. When side holes 24, 34 are provided, fluid flows in and out not only through the open ends 23, 33 of the tail portions 21, 31 but also through the side holes 24, 34, thereby increasing the amount of fluid flowing inside the tubular member and improving the drainage effect.

[0053] The side holes 24, 34 may be provided in only one or both of the tail portions 21, 31, but are preferably provided on the side surface of the tail portion 21, which is located upstream of the fluid. This increases the amount of fluid flowing into the tube stent 1, significantly improving the drainage effect. However, since it is undesirable for fluid to leak to the outside from the straight body portion 11, it is preferable not to provide side holes in the straight body portion 11.

[0054] Furthermore, an endoscopic marker that can be confirmed under an endoscopic image may be provided on the tube stent 1. The endoscopic marker is not particularly limited, but may be formed, for example, by coloring a part of the outer circumferential surface of the tube member in a ring shape.

[0055] Next, a tube stent delivery device 100 for placing a tube stent 1 in a bile duct according to an embodiment of the present invention will be described with reference to Figures 2 to 4. Figure 2 is a plan view showing an example of a tube stent delivery device 100 for placing a tube stent 1 in a bile duct according to an embodiment of the present invention. Figure 3 is a plan view showing an inner catheter of the tube stent delivery device 100 shown in Figure 2, and Figure 4 is a plan view showing an outer catheter of the tube stent delivery device 100 shown in Figure 2.

[0056] The tubular stent delivery device 100 shown in FIG. 2 is a medical treatment tool used to place a tubular stent 1 inside the body, and is an endoscopic type device that is inserted into the body via a treatment tool guide tube of an endoscope.

[0057] The tube stent 1 in this embodiment is a stent that is placed in digestive tissue, such as the digestive tract, to penetrate the digestive tissue wall and allow fluid to circulate. As described above, it can be used in various placement locations and for various purposes. Here, as an example, the tube stent 1 in this embodiment is a stent that connects the gallbladder and duodenum to allow bile to circulate, and a tube stent delivery device 100 for endoscopically placing the stent so that it penetrates the gallbladder wall and the duodenal wall will be described. Note that the tube stent delivery device 100 used to place the tube stent 1 in the body in this embodiment is merely an example and is not limited to this. Instead of an endoscopic device that is inserted through a treatment instrument guide tube of an endoscope, a percutaneous device that approaches by directly inserting a needle may also be used.

[0058] 2 is generally configured to include a long and thin catheter portion 120 that is inserted into the patient's body (lumen) through a treatment tool guide tube of an endoscope (not shown), an operation portion 130 that is connected to the proximal end of the catheter portion 120 and that operates the catheter portion 120 inside the body from outside the body, a guide wire 140, and a tube stent 1 that is to be placed. In this specification, the tip side of the tube stent delivery device 100 that is inserted into the patient's body is defined as the distal end side of the tube stent delivery device 100, and the base end side where an operator grasps and operates the tube stent delivery device 100 outside the patient's body is defined as the proximal end side of the tube stent delivery device 100.

[0059] The catheter portion 120 includes an inner sheath (inner tube) 121 having a distal end and a proximal end, and an outer sheath (outer tube) 122 having a distal end and a proximal end. Radiopaque markers (not shown) are attached near the distal ends of the inner sheath 121 and the outer sheath 122. The radiopaque markers are position detection markers that can be confirmed by X-ray fluoroscopy when the catheter portion 120 is inserted into the patient's body, and are formed, for example, from a metal material such as gold, platinum, or tungsten, or a polymer blended with barium sulfate or bismuth oxide.

[0060] The inner sheath 121 is made of a flexible, elongated tube. A guide wire 140 is inserted through the lumen of the inner sheath 121 and is used as a guide for inserting the tube stent delivery device 100 into the patient's body. After inserting the guide wire 140 into the body to secure a path between the outside and inside of the body, the catheter portion 120 is advanced along the guide wire 140, thereby allowing the distal end of the catheter portion 120 to be inserted into a target site inside the body. The outer diameter of the inner sheath 121 is approximately 0.5 mm to 4.0 mm.

[0061] A distal tapered section 123 is formed at the distal end of the inner sheath 121. The distal tapered section 123 is tapered toward the tip (distal end). Instead of the distal tapered section 123, a distal tip having a similar tapered shape may be prepared separately from the inner sheath 121 and attached to the distal end of the inner sheath 121.

[0062] The outer sheath 122 is made of a flexible, elongated tube. The outer sheath 122 has an inner diameter slightly larger than the outer diameter of the inner sheath 121, and the inner sheath 121 is inserted inside the outer sheath 122 so as to be relatively slidable. For example, the inner diameter of the outer sheath 122 is approximately 0.5 mm to 4.5 mm, and the outer diameter of the outer sheath 122 is approximately 1.0 mm to 5.0 mm. An operating unit 130 is connected to the proximal end of the outer sheath 122, and when an operator operates a connector 131 of the operating unit 130, the inner sheath 121 can slide (move relatively) in the axial direction with respect to the outer sheath 122.

[0063] Examples of materials that can be used for the inner sheath 121 and the outer sheath 122 include various resin materials such as polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyurethane, ethylene-vinyl acetate copolymer, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamide, polyether polyamide, polyester polyamide, polyether ether ketone, polyetherimide, fluorine-based resins such as polytetrafluoroethylene and tetrafluoroethylene-hexafluoropropylene copolymer, and various thermoplastic elastomers such as polystyrene, polyolefin, polyurethane, polyester, polyamide, and polybutadiene. Two or more of these materials can also be used in combination.

[0064] The operation unit 130 includes a connector 131 and a connector 132. As shown in Fig. 3, the connector 131 is connected and fixed to the proximal end of the inner sheath 121. As shown in Fig. 4, the connector 132 is connected and fixed to the proximal end of the outer sheath 122. The connector 131 has a through-hole that passes through in the axial direction, and this through-hole communicates with the inner lumen of the inner sheath 121. The connector 132 has a through-hole that passes through in the axial direction, and this through-hole communicates with the inner lumen of the outer sheath 122. The distal end of the connector 131 and the proximal end of the connector 132 can be coupled and released from each other by a luer lock system or the like.

[0065] The guide wire 140 is inserted through the lumen of the inner sheath 121 over the entire length thereof. The distal end of the guide wire 140 can protrude from the tapered tip portion 123 of the inner sheath 121, and the proximal end of the guide wire 140 can be exposed to the outside through the through-hole of the connector 131.

[0066] When inserting the tube stent delivery device 100 into the patient's body, the tube stent 1 is attached to the distal end side of the tube stent delivery device 100, as shown in Fig. 2. Specifically, the distal end portion of the inner sheath 121 is inserted inside the tube stent 1, and the end face on the proximal end side of the tube stent 1 is abutted against the end face on the distal end side of the outer sheath 122 through which the inner sheath 121 is inserted. In this way, the tube stent 1 is arranged in line with the outer sheath 122, with the inner sheath 121 inserted inside it.

[0067] As described above, the tail portions 21, 31 of the tube stent 1 have at least a partially curved shape, but when the tube stent 1 is attached to the distal end side of the tube stent delivery device 100, the tail portions 21, 31 are elastically deformed into an approximately straight shape to match the shape of the inner sheath 121.

[0068] When placing the tube stent 1 in the body, first, the tip of the transnasal or oral endoscope is advanced to the upper part of the duodenum (the position closest to the gallbladder), and the tip is punctured from the duodenum toward the gallbladder, and a guidewire 140 is inserted into the puncture hole through the treatment instrument guide tube of the endoscope. Next, the connectors 131 and 132 are joined together, and with the tube stent 1 attached to the distal end side of the inner sheath 121, the catheter portion 120 is advanced along the guidewire 140.

[0069] The tube stent 1 is inserted to an appropriate position in the bile duct while checking the positions of the inner sheath 121 and the outer sheath 122 using X-ray fluoroscopy. Thereafter, the connection between the connectors 131 and 132 is released, and the inner sheath 121 and the guide wire 140 are slid toward the proximal end and pulled out while leaving the outer sheath 122 in its original position, and then the outer sheath 122 is pulled out, thereby placing the tube stent 1 between the gallbladder and the duodenum, for example, as shown schematically in Fig. 5.

[0070] 5 is a schematic diagram showing a state in which a tube stent 1 according to an embodiment of the present invention is placed to connect a gallbladder 65 and a duodenum 67. In FIG. 5, a cross section of the inside of a body is shown, showing the digestive organs of the liver 61, stomach 62, pancreas 63, common bile duct 64, gallbladder 65, cystic duct 66, and duodenum 67, an endoscope 200 with its tip positioned in the upper part of the duodenum 67, and the tube stent 1 placed between the gallbladder 65 and the duodenum 67.

[0071] For example, if a gallstone becomes lodged in the cystic duct 66, the cystic duct 66 may become clogged, inhibiting the flow of bile. In such a case, by placing a tube stent 1 so as to connect the gallbladder 65 and the duodenum 67 as shown in Figure 5, the tube stent 1 can ensure the flow of bile.

[0072] The tube stent 1 placed to connect the gallbladder 65 and the duodenum 67 will be described in more detail with reference to Fig. 6. Fig. 6 is a schematic diagram showing in more detail the state in which the tube stent 1 according to an embodiment of the present invention is placed to connect the gallbladder 65 and the duodenum 67. Fig. 6 schematically shows the vicinity of the tube stent 1 shown in Fig. 5, illustrating the gallbladder 65 and the gallbladder wall 65a, the duodenum 67 and the duodenal wall 67a, and the tube stent 1. Note that cross sections of the gallbladder wall 65a and the duodenal wall 67a are shown.

[0073] As shown in Figure 6, the tube stent 1 is positioned so that the straight body portion 11 penetrates the gallbladder wall 65a and the duodenal wall 67a. One tail portion 21 is positioned within the gallbladder 65, and the other tail portion 31 is positioned within the duodenum 67. By placing the tube stent 1 in this manner, the inside of the gallbladder 65 and the inside of the duodenum 67 are connected via the tube stent 1. Bile stored in the gallbladder 65 flows in through the open end 23 and side holes 24 of the upstream tail portion 21, passes through the straight body portion 11, and flows out through the open end 33 and side holes 34 of the downstream tail portion 31, ensuring a smooth flow path for bile.

[0074] In the tube stent 1, the contact portion 22 of the tail portion 21 and the contact portion 32 of the tail portion 31 are separated by a distance D. The tail portions 21 and 31 are elastic, and if the separation distance D increases, they will return to their original state of separation distance D. With this configuration, as shown in FIG. 6 , the contact portion 22 of the tail portion 21 contacts the gallbladder wall 65a from the inside of the gallbladder 65, and a force F1 acts in a direction that presses against the gallbladder wall 65a. Similarly, the contact portion 32 of the tail portion 31 contacts the duodenal wall 67a from the inside of the duodenum 67, and a force F2 acts in a direction that presses against the duodenal wall 67a. In other words, the contact portions 22 and 32 of the tail portions 21 and 31, located at both ends of the tube stent 1, contact the gallbladder wall 65a and the duodenal wall 67a, respectively, and press against them from both sides. This allows the tube stent 1 to be placed stably without displacement, and the effect of preventing the migration of the tube stent 1 can be improved.

[0075] While the tube stent 1 is placed in the body, the gallbladder wall 65a and the duodenal wall 67a are maintained under pressure from the contact portions 22, 32. This promotes adhesion in the contact area between the gallbladder wall 65a and the duodenal wall 67a. When the tube stent 1 is removed after the gallbladder wall 65a and the duodenal wall 67a have sufficiently adhered, a penetration mark 70 remains at the point of penetration of the straight body portion 11, as shown in FIG. 7, and the gallbladder wall 65a and the duodenal wall 67a around the penetration mark 70 become adhered. This ensures that a bile flow path is maintained through the penetration mark 70 even after the tube stent 1 is removed. Furthermore, the gallbladder 65 can be approached from the duodenum 67 through the penetration mark 70, facilitating further treatment of the gallbladder 65.

[0076] As shown in Figure 6, the tube stent 1 is arranged so that the contact portions 22, 32 of the tail portions 21, 31 face each other in the axial direction of the straight body portion 11. This configuration allows the contact portions 22, 32 to sandwich the same location of the gallbladder wall 65a and the duodenal wall 67a from approximately perpendicular directions, thereby achieving a more effective migration prevention effect. This also improves the ability to adhere the gallbladder wall 65a and the duodenal wall 67a to each other.

[0077] Derivative examples of the tube stent according to the embodiment of the present invention will be described below.

[0078] Fig. 8 is a perspective view showing a first derivative example of a tube stent according to an embodiment of the present invention. The tube stent 1A shown in Fig. 8 is composed of a straight body portion 11A having a substantially linear shape and a pair of tail portions 21A, 31A, each of which has a curved shape at least in part and is connected to both ends of the straight body portion 11A.

[0079] The contact portions 22A, 32A (shaded areas in Figure 8) of the tail portions 21A, 31A that come into contact with the digestive tissue wall when the tube stent 1A is placed in the body are adjacent to each other in a natural state where no external load is applied, and the separation distance D between the contact portions 22A, 32A is within the preferred range described above.

[0080] When the tube stent 1A is placed in the body, the open ends 23A and 33A of the tail portions 21A and 31A serve as an inlet and outlet for fluid, respectively, allowing fluid to circulate through the lumen of the tubular member. Note that, as with the tube stent 1 shown in Fig. 1, side holes may be provided in the tail portions 21A and 31A.

[0081] In the tube stent 1A shown in Fig. 8, the loop surfaces of the tail portions 21A and 31A intersect at a predetermined angle. More specifically, the tail portion 21A is wound toward the front side of the paper in Fig. 8, and the tail portion 31A is wound toward the back side of the paper in Fig. 8. That is, the open end 23A, which is the end of the tail portion 21A, is located toward the front side, and the open end 33A, which is the end of the tail portion 31A, is located toward the back side. Although the contact portions 22A and 32A are not positioned opposite each other, even in this case, the effects of preventing migration, bringing different digestive tracts close together, and adhering the digestive tissue walls can be obtained.

[0082] Fig. 9 is a perspective view showing a second derivative example of a tube stent according to an embodiment of the present invention. The tube stent 1B shown in Fig. 9 is composed of a straight body portion 11B having a substantially linear shape and a pair of tail portions 21B, 31B, each of which has a curved shape at least partially and is connected to both ends of the straight body portion 11B.

[0083] The contact portions 22B, 32B (shaded areas in Figure 9) of the tail portions 21B, 31B that come into contact with the digestive tissue wall when the tube stent 1B is placed in the body are adjacent to each other in a natural state where no external load is applied, and the separation distance D between the contact portions 22B, 32B is within the preferred range described above.

[0084] When the tube stent 1B is placed in the body, the open ends 23B and 33B of the tail portions 21B and 31B serve as an inlet and outlet for fluid, respectively, allowing fluid to circulate through the lumen of the tubular member. Note that, as with the tube stent 1 shown in Fig. 1, side holes may be provided in the tail portions 21B and 31B.

[0085] The tube stent 1B shown in Figure 9 has tail sections 21B and 31B that are loosely wound compared to the tube stent 1 shown in Figure 1, with contact section 22B located near open end 23B of tail section 21B and contact section 32B located near open end 33B of tail section 31B. Even when tail sections 21B and 31B are loosely wound in this way, the effects of preventing migration, bringing different digestive tracts closer together, and adhering the walls of digestive tissues can be obtained.

[0086] Fig. 10 is a perspective view showing a third derivative example of a tube stent according to an embodiment of the present invention. The tube stent 1C shown in Fig. 10 is composed of a straight body portion 11C having a substantially linear shape and a pair of tail portions 21C, 31C, each of which has a curved shape at least partially and is connected to both ends of the straight body portion 11C.

[0087] The contact portions 22C, 32C (shaded areas in Figure 10) of the tail portions 21C, 31C that come into contact with the walls of digestive tissue when the tube stent 1C is placed in the body are adjacent to each other in a natural state where no external load is applied, and the separation distance D between the contact portions 22C, 32C is within the preferred range described above.

[0088] The tube stent 1C shown in Figure 10 has an extension 41C that extends the tubular structure at the open end of the tail section 21C, which is located upstream when the tube stent 1C is placed in the body. The extension 41C is a tubular member, and one end of the extension 41C is connected to the open end of the tail section 21C (connection position P3), and the other end of the extension 41C forms an open end 43C. While Figure 10 shows the extension 41C formed in a substantially linear shape, the extension 41C is not particularly limited and may be curved. For example, the shape of the extension 41C can be adapted to the shape of the digestive tract, where the tube stent 1C will be placed, thereby stabilizing the placement of the extension 41C.

[0089] 10, the extension 41C may be provided with one or more side holes 44C. The side holes 44C provided in the extension 41C are through-holes that penetrate the tube wall of the tube member that constitutes the extension 41C. The positions and number of the side holes 44C in the extension 41C are not particularly limited.

[0090] When the tube stent 1C is placed in the body, the open end 43C of the extension portion 41C and the open end 33C of the tail portion 31C serve as an inlet and outlet for fluid, allowing fluid to circulate through the lumen of the tubular member. Note that, as with the tube stent 1 shown in Fig. 1, side holes may be provided in the tail portions 21C, 31C.

[0091] Furthermore, by providing side holes 44C in extension portion 41C, fluid flows into extension portion 41C not only through open end 43C but also through side holes 44C, thereby increasing the amount of fluid flowing within the tube member and further improving the drainage effect.

[0092] In Figure 10, an extension portion 41C is provided on the tail portion 21C, which is located on the upstream side when the tube stent 1C is placed in the body, but an extension portion may also be provided on the tail portion 31C, which is located on the downstream side, or extension portions may be provided on both the tail portions 21C and 31C.

[0093] Fig. 11 is a perspective view showing a fourth variation of a tube stent according to an embodiment of the present invention. A tube stent 1D shown in Fig. 11 is composed of a straight body portion 11D having a substantially linear shape and a pair of tail portions 21D, 31D, each of which has a curved shape at least partially and is connected to both ends of the straight body portion 11D.

[0094] The contact portions 22D, 32D (shaded areas in Figure 11) of the tail portions 21D, 31D that come into contact with the walls of digestive tissue when the tube stent 1D is placed in the body are adjacent to each other in a natural state where no external load is applied, and the separation distance D between the contact portions 22D, 32D is within the preferred range described above.

[0095] When the tube stent 1D is placed in the body, the open ends 23D and 33D of the tail portions 21D and 31D serve as an inlet and outlet for fluid, respectively, allowing fluid to circulate through the lumen of the tubular member. Note that, as with the tube stent 1 shown in Fig. 1, the tail portions 21D and 31D may be provided with side holes.

[0096] 11, tail portions 21D, 31D are configured to have straight members 25D, 35D, respectively, extending in a direction approximately perpendicular to the axis of body portion 11D, at positions adjacent to tail portions 21D, 31D. Furthermore, contact portions 22D, 32D extend in an approximately linear fashion on straight members 25D, 35D. With this configuration, when tube stent 1D is placed in the body, contact portions 22D, 32D, which extend in an approximately linear fashion, come into contact with the digestive tissue wall. This increases the contact area between contact portions 22D, 32D and the digestive tissue wall, thereby further improving the migration prevention effect and also improving the effect of bringing different digestive tissues closer together and adhering them together.

[0097] In addition, in FIG. 11, the straight members 25D and 35D are provided on both the tail portions 21D and 31D, but the straight member may be provided on only one of the tail portions 21D and 31D.

[0098] Fig. 12 is a perspective view showing a fifth variation of a tube stent according to an embodiment of the present invention. The tube stent 1E shown in Fig. 12 is composed of a straight body portion 11E having a substantially linear shape and a pair of tail portions 21E, 31E, each of which has a curved shape at least partially and is connected to both ends of the straight body portion 11E.

[0099] The contact portions 22E, 32E (shaded areas in Figure 12) of the tail portions 21E, 31E that come into contact with the digestive tissue wall when the tube stent 1E is placed in the body are adjacent to each other in a natural state where no external load is applied, and the separation distance D between the contact portions 22E, 32E is within the preferred range described above.

[0100] When the tube stent 1E is placed in the body, the open ends 23E and 33E of the tail portions 21E and 31E serve as an inlet and outlet for fluid, respectively, allowing fluid to circulate through the lumen of the tubular member. Note that, as with the tube stent 1 shown in Fig. 1, the tail portions 21E and 31E may be provided with side holes.

[0101] As shown in FIG. 12, the tail portions 21E, 31E are each curved around the axis of the straight body portion 11E. More specifically, the tail portions 21E, 31E are formed in a spiral shape wound around the axis of the straight body portion 11E. The spiral tail portions 21E, 31E extend in a direction approximately perpendicular to the axial direction of the straight body portion 11E near connection positions P4, P5 with the straight body portion 11E (the ends of the straight body portion 11E on the tail portion 21E, 31E side), and the contact portions 22E, 32E extend near the connection positions P4, P5. With this configuration, when the tube stent 1E is placed in the body, the contact portions 22E, 32E come into contact with the digestive tissue wall, thereby increasing the contact area between the contact portions 22E, 32E and the digestive tissue wall, thereby further improving the migration prevention effect and improving the effect of bringing different digestive tissues closer together and causing them to adhere to each other.

[0102] In addition, although both tail portions 21E and 31E are formed in a spiral shape in FIG. 12, only one of tail portions 21E and 31E may be formed in a spiral shape.

[0103] The operation of the present invention will be described below.

[0104] The tube stents 1, 1A, 1B, 1C, 1D, and 1E in this embodiment are tube stents made of flexible tubular members, and are composed of straight body portions 11, 11A, 11B, 11C, 11D, and 11E having an approximately linear shape, and a pair of tail portions 21, 21A, 21B, 21C, 21D, 21E, 31, 31A, 31B, 31C, 31D, and 31E having at least a partially curved shape and connected to both ends of the straight body portions 11, 11A, 11B, 11C, 11D, and 11E, respectively. A pair of tail portions 21, 21A, 21B, 21C, 21D, 21E, 31, 31A, 31B, 31C, 31D, 31E respectively have contact portions 22, 22A, 22B, 22C, 22D, 22E, 32, 32A, 32B, 32C, 32D, 32E that come into contact with the digestive tissue wall, and the axial separation distance D between the contact portions 22, 22A, 22B, 22C, 22D, 22E, 32, 32A, 32B, 32C, 32D, 32E of the straight body portions 11, 11A, 11B, 11C, 11D, 11E is 3 cm or less.

[0105] With this configuration, the contact portions of the pair of tail portions located at both ends of the tubular stent come into contact with the digestive tissue wall so as to sandwich the wall, thereby restricting the movement of the tubular stent and improving the migration prevention effect, particularly when the digestive tissue wall in which the tubular stent is placed is thin.Furthermore, with this configuration, when the pair of tail portions are placed in different digestive tissues, the different digestive tissues can be brought into close proximity with each other, and adhesion between the different digestive tissue walls can also be promoted.

[0106] In the tube stents 1, 1B, 1C, 1D, and 1E of this embodiment, a pair of tail portions 21, 21B, 21C, 21D, 21E, 31, 31B, 31C, 31D, and 31E may each be curved so that the contact portions 22, 22B, 22C, 22D, 22E, 32, 32B, 32C, 32D, and 32E face each other in the axial direction of the straight body portions 11, 11B, 11C, 11D, and 11E.

[0107] This configuration allows the contact portion to clamp the same location on the digestive tissue wall, thereby further improving the migration prevention effect and also improving the effect of bringing different digestive tissues closer together and causing them to adhere to each other.

[0108] In the tube stents 1, 1B, 1C, and 1D of the present embodiment, the surfaces formed by the curved shapes of the pair of tail portions 21, 21B, 21C, 21D, 31, 31B, 31C, and 31D may be substantially flush with each other.

[0109] This configuration allows the contact portion to clamp the same location on the digestive tissue wall, thereby further improving the migration prevention effect and also improving the effect of bringing different digestive tissues closer together and causing them to adhere to each other.

[0110] The tube stents 1, 1A, 1B, 1C, 1D, and 1E in this embodiment may have one or more side holes 24, 34 provided on at least one side of the pair of tail portions 21, 21A, 21B, 21C, 21D, 21E, 31, 31A, 31B, 31C, 31D, and 31E.

[0111] This configuration increases the amount of fluid flowing in and out of the tube stent, improving the drainage effect of the tube stent.

[0112] In this embodiment, the tube stents 1, 1A, 1B, 1C, 1D, and 1E may have one or more side holes 24 provided on the side of the tail portions 21, 21A, 21B, 21C, 21D, and 21E that are located upstream of the fluid flowing through the tube stent.

[0113] This configuration allows the fluid to flow efficiently into the tube stent, significantly improving the drainage effect of the tube stent.

[0114] The tube stent 1C in this embodiment may be provided with an extension 41C on the open end side of at least one of the pair of tail portions 21C, 31C, for extending the tube structure of the tube stent.

[0115] This configuration makes it possible to use the extension portion to stabilize the tube stent and to use the extension portion to improve the drainage effect of the tube stent.

[0116] The tube stent 1C in this embodiment may have one or more side holes 44C provided on the side surface of the extension portion 41C.

[0117] This configuration makes it possible to improve the efficiency of fluid inflow and outflow in the tube stent and increase the amount of fluid, thereby significantly improving the drainage effect of the tube stent.

[0118] In the tube stent 1D of this embodiment, at least one or both of the contact portions 22D, 32D of the pair of tail portions 21D, 31D may extend in a substantially straight line along the wall of the digestive tissue.

[0119] This configuration increases the area of ​​contact between at least one or both of the contact portions of the pair of tail portions and the digestive tissue wall, thereby further improving the migration prevention effect and also improving the effect of bringing different digestive tissues closer together and causing them to adhere to each other.

[0120] In the tube stent 1E of this embodiment, at least one or both of the pair of tail portions 21E, 31E may be curved around the axis of the straight body portion 11E.

[0121] This configuration increases the area of ​​contact between at least one or both of the contact portions of the pair of tail portions and the digestive tissue wall, thereby further improving the migration prevention effect and also improving the effect of bringing different digestive tissues closer together and causing them to adhere to each other.

[0122] The above-described embodiments are provided to facilitate understanding of the present invention and are not intended to limit the present invention. Therefore, the elements disclosed in the above-described embodiments are intended to encompass all design modifications and equivalents within the technical scope of the present invention. For example, the tube stents disclosed in the above-described embodiments are not limited to the shapes shown in Figures 1 and 8 to 12. Tube stents obtained by arbitrarily combining one shape of the tail portion with the other shape shown in Figures 1 and 8 to 12 are also encompassed within the scope of the present invention. [Explanation of symbols]

[0123] 1, 1A, 1B, 1C, 1D, 1E Tube stent 11, 11A, 11B, 11C, 11D, 11E Straight body part 21, 21A, 21B, 21C, 21D, 21E, 31, 31A, 31B, 31C, 31D, 31E Tail section 22, 22A, 22B, 22C, 22D, 22E, 32, 32A, 32B, 32C, 32D, 32E Contact part 23, 23A, 23B, 23D, 23E, 33, 33A, 33B, 33C, 33D, 33E, 43C Open end 24, 34, 44C side hole 25D, 35D straight members 41C Extension 61 Liver 62 Stomach 63 Pancreas 64 Common bile duct 65 Gallbladder 65a Gallbladder wall 66 Cystic duct 67 Duodenum 67a Duodenal wall 70 Penetration marks 100 Tube stent delivery device 120 Catheter section 121 Inner sheath (inner tube) 122 Outer sheath (outer tube) 123 Tapered tip 130 Operation section 131, 132 connectors 140 Guidewire 200 Endoscope

Claims

1. A tube stent made of a flexible tubular member, a straight body portion having a substantially linear shape; a pair of tail portions each connected to both ends of the straight body portion and having at least a partially curved shape; It is composed of the pair of tail portions each have a contact portion that contacts a wall of digestive tract tissue, and the distance between the contact portions in the axial direction of the straight body portion is 3 cm or less; A tube stent characterized in that one or more side holes are provided on the side surface of at least one of the pair of tail portions, and the side holes are through holes that penetrate the tubular wall of the tubular member.

2. The tube stent according to claim 1, wherein the pair of tail portions are curved such that the contact portions face each other in the axial direction of the body portion.

3. 3. The tube stent according to claim 1, wherein the surfaces formed by the curved shapes of the pair of tail portions are substantially flush with each other.

4. A tube stent as described in any one of claims 1 to 3, characterized in that the one or more side holes are provided on the side of the tail portion located upstream of the fluid flowing within the tube stent.

5. 5. The tube stent according to claim 1, wherein an extension portion for extending the tubular structure of the tube stent is provided on the open end side of at least one of the pair of tail portions.

6. The tube stent according to claim 5, wherein the extension portion has one or more side holes on the side surface of the extension portion.

7. 7. The tube stent according to claim 1, wherein the contact portion of at least one of the pair of tail portions extends in a substantially straight line along the wall of the digestive tissue.

8. The tube stent according to claim 7, wherein the contact portions of both of the pair of tail portions extend substantially linearly along the wall of the digestive tissue.

9. 3. The tube stent according to claim 1, wherein at least one of the pair of tail portions is curved around the axis of the straight body portion.

10. 10. The tube stent according to claim 9, wherein both of the pair of tail portions are curved around the axis of the straight body portion.

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