JP7826644B2 - Tube stent - Google Patents

Description

The present invention relates to a tube stent that is placed within digestive tissue, such as the digestive tract, to allow fluid to pass through the digestive tissue wall.

Drainage (stent placement) has traditionally been performed endoscopically to drain fluid from a body cavity by placing a tube stent. Known tube stents used in stent placement include tube stents molded into various shapes, as disclosed in Patent Documents 1 and 2 below, for example.

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.

Patent document 2 discloses multiple tube stents each having a stent arc portion, at least one end of which is made up of at least a portion of an arc.

As exemplified 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 pigtail-type stents, the pigtail shape of the stent ends has a migration prevention effect, preventing the stent from shifting position or falling off.

Special Publication No. 2013-521868 Japanese Patent Application Laid-Open No. 2015-8862

However, in conventional pigtail stents, the separation between the two ends of the pigtail-shaped stent is set to approximately 5 to 15 cm. Although conventional pigtail stents serve to prevent the stent ends from shifting or falling out, there are problems with unstable stent placement, such as the tubular stent moving in the penetration direction or the stent ends moving, particularly when the gastrointestinal tissue wall in which the tubular stent is placed is thin.

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

To achieve the above objective, 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 a substantially 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, each of the pair of tail portions having 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.

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

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

This configuration allows the contact portion to clamp the same location on the digestive tissue wall, 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.

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.

This configuration allows the contact portion to clamp the same location on the digestive tissue wall, 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.

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

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

In the tube stent of the present invention, the one or more side holes may be provided on the side of the tail portion located upstream of the fluid flowing through the tube stent.

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

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 tubular structure of the tube stent.

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

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

This configuration improves the efficiency of fluid inflow and outflow through the tube stent and increases the amount of fluid, significantly improving the drainage effect of the tube stent.

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.

This configuration increases the contact area of at least one of the pair of tail sections with the wall of digestive tissue, 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.

In the tube stent according to the present invention, the contact portions of both of the pair of tail portions may each extend in a substantially straight line along the wall of the digestive tissue.

This configuration increases the contact area of both contact portions of the pair of tail sections with the digestive tissue wall, 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.

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.

This configuration increases the contact area of at least one of the pair of tail sections with the wall of digestive tissue, 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.

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.

This configuration increases the contact area of both contact portions of the pair of tail sections with the digestive tissue wall, 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.

The present invention provides a tube stent that achieves an appropriate patency with a simple configuration and has excellent migration prevention effects, particularly when the gastrointestinal tissue wall in which the tube stent is placed is thin.

FIG. 1 is a perspective view showing an example of a tube stent according to an embodiment of the present invention. 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. FIG. 3 is a plan view showing the inner catheter of the tube stent delivery device shown in FIG. 2. FIG. 3 is a plan view showing the outer catheter of the tube stent delivery device shown in FIG. 2. 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. 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. FIG. 7 is a schematic diagram showing the state after the tube stent shown in FIG. 6 has been removed. FIG. 1 is a perspective view showing a first derivative example of a tube stent according to an embodiment of the present invention. FIG. 10 is a perspective view showing a second derivative example of a tube stent according to an embodiment of the present invention. FIG. 10 is a perspective view showing a third derivative example of a tube stent according to an embodiment of the present invention. FIG. 10 is a perspective view showing a fourth derivative example of a tube stent according to an embodiment of the present invention. FIG. 10 is a perspective view showing a fifth derivative example of a tube stent according to an embodiment of the present invention.

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

The tube stent of the present invention is placed in digestive tissue, such as the digestive tract, so as to penetrate the relatively thin walls of the digestive tissue to allow fluid (liquid or gas) to pass through the walls. 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 blocked by 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 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.

Figure 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 Figure 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 Figure 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.

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. Furthermore, in the following, it is assumed that 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 it is 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 within the gallbladder (upstream of the bile) and the tail portion 31 is positioned within the duodenum (downstream of the bile).

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

A substantially linear shape means that the shape is substantially linear in its natural state when no external load is applied; more specifically, for example, it means that the approximate central axis of the lumen inside the tubular member is substantially linear.

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, if the tube stent 1 is a stent connecting the gallbladder and duodenum, the straight body portion 11 is positioned so as to penetrate the gallbladder wall and the duodenal wall.

Tail portions 21, 31 are each located at the end of the flexible tubular member that constitutes tube stent 1. Tail portions 21, 31 are molded so that at least a portion is curved, and may be molded into a shape known as a pigtail or alpha loop, for example. There are no particular limitations on the size of tail portions 21, 31, but the outer diameter of the annulus formed by tail portions 21, 31 is typically about 1 cm.

A curved shape refers to a shape that is curved in its natural state when no external load is applied, and more specifically, refers to a shape in which, for example, the approximate central axis of the lumen within the tubular member is curved.

The tail portions 21, 31 may be curved with approximately the same curvature (approximately a perfect circle), or may be curved only partially, or may be curved with partially different curvatures. In the tube stent 1 shown in Figure 1, the tail portions 21, 31 are molded in the same shape symmetrical across the straight body portion 11, but the tail portions 21, 31 may also have different shapes.

In the tube stent 1 shown in Figure 1, the surfaces formed by the curved shapes of the tail sections 21, 31 (surfaces including the arcs formed by the intermediate portions of the tail sections 21, 31; hereinafter referred to as loop surfaces) are configured to be contained within a substantially flat plane. However, the curved shape (spiral shape) may also be formed by moving the tube member perpendicularly to the loop surface. Furthermore, in the tube stent 1 shown in Figure 1, the tail sections 21, 31 are wound symmetrically on either side of the straight body section 11, and the loop surfaces of the tail sections 21, 31 are configured to be substantially on the same plane. However, the loop surfaces of the tail sections 21, 31 may also be configured to be on different planes.

The tail sections 21, 31 are curved back toward the body section 11. It is preferable that at least a portion of the tail section 21 is located closer to the center of the body section 11 in the axial direction of the body section 11 than the connection position P1 with the body section 11 (the end of the body section 11 on the tail section 21 side). Similarly, it is preferable that at least a portion of the tail section 31 is located closer to the center of the body section 11 in the axial direction of the body section 11 than the connection position P2 with the body section 11 (the end of the body section 11 on the tail section 31 side).

The tail portions 21, 31 each have contact portions 22, 32 in the region located toward the center of the straight body portion 11 of the tail portions 21, 31 (the shaded region in Figure 1). When the tube stent 1 is placed in the body, the tail portions 21, 31 are positioned on either side of the digestive tissue wall, and the contact portions 22, 32 located on the inside of the tail portions 21, 31 come into contact with the digestive tissue wall.

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

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 duodenum, the tail portions 21, 31 are positioned between the gallbladder wall and the duodenal wall. 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 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.

The separation distance D between the contact portions 22, 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, 31 may intersect, with the contact portion 22 of the tail portion 21 positioned closer to 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 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, 31 intersect, it is preferable that the separation distance D between the contact portions 22 and 32 be 1 cm or less. The state in which the tail portions 21, 31 intersect can be expressed as a negative separation distance D, and the preferred range for separation distance D in this embodiment can be expressed as -1 cm or more and 3 cm or less.

Tail portion 21 and tail portion 31 are pre-curved, with at least a portion curved. In their natural state, with no external load applied, contact portion 22 of tail portion 21 and contact portion 32 of tail portion 31 are separated by a distance D. However, if this distance D changes, an elastic force acts to return them to their original state separated by distance D.

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

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 forms open ends 23, 33 that open to the lumen within the tubular member. When the tube stent 1 is placed in the body, the open ends 23, 33 of the tail portions 21, 31, respectively, serve as fluid inlet and outlet ports, allowing fluid to circulate through the lumen of the tubular member.

The tail portion 21, 31 may be provided with one or more side holes 24, 34. The side holes 24, 34 provided in the tail portion 21, 31 are through-holes that penetrate the tube wall of the tube member. There are no particular limitations on the location or number of side holes 24, 34 provided in the tail portion 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 portion 21, 31 but also through the side holes 24, 34, thereby increasing the amount of fluid flowing within the tube member and improving the drainage effect.

The side holes 24, 34 may be provided on only one or both of the tail portions 21, 31, but are preferably provided on the side 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.

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

Next, with reference to Figures 2 to 4, 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. 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 the inner catheter of the tube stent delivery device 100 shown in Figure 2, and Figure 4 is a plan view showing the outer catheter of the tube stent delivery device 100 shown in Figure 2.

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

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 a variety of placement locations and applications. 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 the treatment instrument guide tube of an endoscope, a percutaneous device that approaches by direct needle insertion may also be used.

The tube stent delivery device 100 shown in Figure 2 is generally composed of an elongated catheter portion 120 that is inserted into a patient's body (lumen) through a treatment instrument guide tube of an endoscope (not shown), an operating portion 130 that is connected to the proximal end of the catheter portion 120 and is used to operate the catheter portion 120 inside the body from outside the body, a guide wire 140, and a tube stent 1 to be placed. Note that in this specification, the tip end of the tube stent delivery device 100 that is inserted into the patient's body is defined as the distal end of the tube stent delivery device 100, and the base end where an operator grasps and operates the tube stent delivery device 100 outside the patient's body is defined as the proximal end of the tube stent delivery device 100.

The catheter portion 120 comprises 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. Furthermore, radiopaque markers (not shown) are attached near the distal ends of the inner sheath 121 and 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 from, for example, metal materials such as gold, platinum, or tungsten, or polymers blended with barium sulfate or bismuth oxide.

The inner sheath 121 consists of a flexible, elongated tube. A guide wire 140, which is used as a guide for inserting the tube stent delivery device 100 into the patient's body, is inserted through the inner lumen of the inner sheath 121. 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, allowing the distal end of the catheter portion 120 to be inserted into the target site inside the body. The outer diameter of the inner sheath 121 is approximately 0.5 mm to 4.0 mm.

The distal end of the inner sheath 121 is formed with a tapered distal end section 123 that tapers toward the tip (distal end). Instead of the tapered distal end 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.

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 is inserted inside the outer sheath 122 so that the inner sheath 121 can slide relatively inside the outer sheath 122. 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. The operating unit 130 is connected to the proximal end of the outer sheath 122, and when the operator operates the 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.

The inner sheath 121 and the outer sheath 122 can be made of 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.

The operating 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 runs through it in the axial direction, and this through-hole is in communication with the inner lumen of the inner sheath 121. The connector 132 has a through-hole that runs through it in the axial direction, and this through-hole is in communication 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 uncoupled to each other using a luer lock system or the like.

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

When inserting the tube stent delivery device 100 into a patient's body, as shown in Figure 2, the tube stent 1 is attached to the distal end of the tube stent delivery device 100. Specifically, the distal end portion of the inner sheath 121 is inserted inside the tube stent 1, and the proximal end face of the tube stent 1 abuts against the distal end face of the outer sheath 122 through which the inner sheath 121 has been inserted. As a result, the tube stent 1 is positioned in line with the outer sheath 122, with the inner sheath 121 inserted inside it.

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 of the tube stent delivery device 100, the tail portions 21, 31 are elastically deformed into a substantially straight shape to match the shape of the inner sheath 121.

When placing the tube stent 1 inside the body, first, the tip of the nasal or oral endoscope is advanced to the upper part of the duodenum (the position closest to the gallbladder), and then punctured from the duodenum toward the gallbladder. A guidewire 140 is then inserted into the puncture hole via the endoscope's treatment instrument guide tube. Next, connectors 131 and 132 are joined together, and with the tube stent 1 attached to the distal end of the inner sheath 121, the catheter portion 120 is advanced along the guidewire 140.

The tube stent 1 is inserted to an appropriate position in the bile duct while checking the positions of the inner sheath 121 and outer sheath 122 using X-ray fluoroscopy. The connectors 131 and 132 are then released from their connection, and the inner sheath 121 and guidewire 140 are slid toward the proximal end and withdrawn while the outer sheath 122 remains in place. Then, the outer sheath 122 is withdrawn, thereby placing the tube stent 1 between the gallbladder and duodenum, as shown schematically in Figure 5, for example.

Figure 5 is a schematic diagram showing a tube stent 1 in an embodiment of the present invention placed to connect a gallbladder 65 and a duodenum 67. Figure 5 shows a schematic cross-section of the body, including 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 a tube stent 1 placed between the gallbladder 65 and the duodenum 67.

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 connecting the gallbladder 65 and duodenum 67 as shown in Figure 5, the tube stent 1 can ensure a bile flow path.

Referring to Figure 6, the tube stent 1 placed to connect the gallbladder 65 and the duodenum 67 will be described in more detail. Figure 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 has been placed to connect the gallbladder 65 and the duodenum 67. Figure 6 schematically illustrates the vicinity of the tube stent 1 shown in Figure 5, and illustrates the gallbladder 65 and gallbladder wall 65a, the duodenum 67 and duodenal wall 67a, and the tube stent 1. Note that cross sections of the gallbladder wall 65a and the duodenal wall 67a are shown.

As shown in Figure 6, the tube stent 1 is positioned so that its 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 hole 24 of the upstream tail portion 21, passes through the straight body portion 11, and flows out through the open end 33 and side hole 34 of the downstream tail portion 31, ensuring a smooth flow path for bile.

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 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 pushes 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 pushes 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 shifting position, improving the effectiveness of preventing migration of the tube stent 1.

While the tube stent 1 is indwelling in the body, the gallbladder wall 65a and the duodenal wall 67a remain under pressure from the contact portions 22, 32. This promotes adhesion in the contact areas 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, the penetration point of the straight body portion 11 remains as a penetration mark 70, 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 now be approached from the duodenum 67 through the penetration mark 70, facilitating further treatment of the gallbladder 65.

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 on the gallbladder wall 65a and the duodenal wall 67a from approximately perpendicular directions, thereby achieving a more effective migration prevention effect. It also provides a more excellent ability to adhere the gallbladder wall 65a and the duodenal wall 67a.

The following describes examples of tube stents that are derivatives of embodiments of the present invention.

Figure 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 Figure 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.

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

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

In the tube stent 1A shown in Figure 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 of the paper in Figure 8, and the tail portion 31A is wound toward the back of the paper in Figure 8. In other words, the open end 23A, which is the end of the tail portion 21A, is located toward the front, and the open end 33A, which is the end of the tail portion 31A, is located toward the back. 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 closer together, and adhering the walls of digestive tissue can be obtained.

Figure 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 Figure 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 in part and is connected to both ends of the straight body portion 11B.

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

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

The tube stent 1B shown in Figure 9 has looser windings at the tail portions 21B and 31B compared to the tube stent 1 shown in Figure 1, with contact portion 22B located near the open end 23B of tail portion 21B and contact portion 32B located near the open end 33B of tail portion 31B. Even when the tail portions 21B and 31B are loosely wound, the effects of preventing migration, bringing different digestive tracts closer together, and adhering the walls of digestive tissue can be achieved.

Figure 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 Figure 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 in part and is connected to both ends of the straight body portion 11C.

When the tube stent 1C is placed in the body, the contact portions 22C, 32C (shaded areas in Figure 10) of the tail portions 21C, 31C that come into contact with the digestive tissue wall are adjacent in their natural state without external load, and the separation distance D between the contact portions 22C, 32C is within the preferred range described above.

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

As shown in FIG. 10, the extension portion 41C may be provided with one or more side holes 44C. The side holes 44C provided in the extension portion 41C are through-holes that penetrate the tube wall of the tube member that constitutes the extension portion 41C. There are no particular limitations on the positions or number of side holes 44C provided in the extension portion 41C.

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 fluid inlet and outlet ports, allowing fluid to circulate through the lumen of the tubular member. Note that, as with the tube stent 1 shown in Figure 1, side holes may be provided in the tail portions 21C and 31C.

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

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. However, an extension portion may also be provided on the tail portion 31C, which is located on the downstream side, or on both tail portions 21C and 31C.

Figure 11 is a perspective view showing a fourth derivative example of a tube stent according to an embodiment of the present invention. The tube stent 1D shown in Figure 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 in part and is connected to both ends of the straight body portion 11D.

When the tube stent 1D is placed in the body, the contact portions 22D, 32D (shaded areas in Figure 11) of the tail portions 21D, 31D that come into contact with the wall of digestive tissue are adjacent in their natural state when no external load is applied, and the separation distance D between the contact portions 22D, 32D is within the preferred range described above.

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

As shown in FIG. 11 , tail portions 21D, 31D are configured to have straight members 25D, 35D, respectively, extending substantially perpendicular to the axis of body portion 11D at positions adjacent to tail portions 21D, 31D. Furthermore, contact portions 22D, 32D extend substantially linearly on straight members 25D, 35D. With this configuration, when tube stent 1D is placed in the body, contact portions 22D, 32D, which extend substantially linearly, 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 into proximity and adhering them together.

Note that while Figure 11 shows straight members 25D and 35D provided on both tail portions 21D and 31D, a straight member may be provided on only one of tail portions 21D and 31D.

Figure 12 is a perspective view showing a fifth derivative example of a tube stent according to an embodiment of the present invention. The tube stent 1E shown in Figure 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 in part and is connected to both ends of the straight body portion 11E.

When the tube stent 1E is placed in the body, the contact portions 22E, 32E (shaded areas in Figure 12) of the tail portions 21E, 31E that come into contact with the walls of digestive tissue are adjacent in their natural state when no external load is applied, and the separation distance D between the contact portions 22E, 32E is within the preferred range described above.

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

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

In Figure 12, both tail portions 21E and 31E are formed in a spiral shape, but only one of tail portions 21E and 31E may be formed in a spiral shape.

The following explains the effects of the present invention.

In this embodiment, the tube stents 1, 1A, 1B, 1C, 1D, and 1E are tube stents made of flexible tubular members, and are composed of a straight body portion 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, each of which has a curved shape at least in part and is connected to both ends of the straight body portion 11, 11A, 11B, 11C, 11D, and 11E. The pair of tail portions 21, 21A, 21B, 21C, 21D, 21E, 31, 31A, 31B, 31C, 31D, 31E each have a contact portion 22, 22A, 22B, 22C, 22D, 22E, 32, 32A, 32B, 32C, 32D, 32E that contacts the digestive tissue wall, and the separation distance D between the contact portions 22, 22A, 22B, 22C, 22D, 22E, 32, 32A, 32B, 32C, 32D, 32E in the axial direction of the straight body portions 11, 11A, 11B, 11C, 11D, 11E is 3 cm or less.

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

In the tube stents 1, 1B, 1C, 1D, and 1E of this embodiment, the 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.

This configuration allows the contact portion to clamp the same location on the digestive tissue wall, 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.

In the tube stents 1, 1B, 1C, and 1D of this 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 approximately flush.

This configuration allows the contact portion to clamp the same location on the digestive tissue wall, 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.

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.

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

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

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

The tube stent 1C in this embodiment may be provided with an extension portion 41C on the open end side of at least one of the pair of tail portions 21C, 31C, which extends the tubular structure of the tube stent.

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

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

This configuration improves the efficiency of fluid inflow and outflow through the tube stent and increases the amount of fluid, significantly improving the drainage effect of the tube stent.

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

This configuration increases the contact area of at least one or both of the contact portions of the pair of tail sections with the wall of digestive tissue, 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.

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.

This configuration increases the contact area of at least one or both of the contact portions of the pair of tail sections with the wall of digestive tissue, 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.

The above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above-described embodiments is intended to include all design modifications and equivalents that fall 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 within the scope of the present invention.

1, 1A, 1B, 1C, 1D, 1E Tube stent 11, 11A, 11B, 11C, 11D, 11E Straight body portion 21, 21A, 21B, 21C, 21D, 21E, 31, 31A, 31B, 31C, 31D, 31E Tail portion 22, 22A, 22B, 22C, 22D, 22E, 32, 32A, 32B, 32C, 32D, 32E Contact portion 23, 23A, 23B, 23D, 23E, 33, 33A, 33B, 33C, 33D, 33E, 43C Open end 24, 34, 44C Side hole 25D, 35D Straight member 41C Extension portion 61 Liver 62 Stomach 63 Pancreas 64 Common bile duct 65 Gallbladder 65a Gallbladder wall 66 Cystic duct 67 Duodenum 67a Duodenal wall 70 Perforation scar 100 Tube stent delivery device 120 Catheter portion 121 Inner sheath (inner tube)
122 outer sheath (outer tube)
123: distal tapered portion 130: operation portion 131, 132: connector 140: guide wire 200: endoscope

Claims (10)

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 . A tube stent as described in claim 1, characterized in that the pair of tail portions are each curved so that the contact portions face each other in the axial direction of the straight body portion. A tube stent as described in claim 1 or 2, characterized in that the surfaces formed by the curved shapes of the pair of tail portions are approximately the same plane. 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. 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. 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. 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. 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. A tube stent as described in claim 1 or 2, characterized in that at least one of the pair of tail portions is curved around the axis of the straight body portion. 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.