JP6790717B2 - Stent delivery system - Google Patents

Description

The present invention relates to a delivery system for placing a stent in vivo.

Conventionally, in a stenotic disease (tumor, inflammation, etc.) of a biological duct such as a blood vessel or a digestive tract, a stent is placed in the stenotic part to dilate the stenotic part. As a method of delivering the stent to the narrowed portion, for example, a delivery system using an endoscope is known. The delivery system generally includes an outer cylinder that stores the stent in a reduced diameter at the tip, a guide wire guide tube that is arranged inside the outer cylinder and has a through hole through which a guide wire can be inserted, and a tip of the guide wire guide tube. The stent is provided with a tip tip attached to and arranged so as to close the tip of the outer cylinder, and is inserted into the living body along a guide wire to deliver the stent to the constricted portion (see, for example, Patent Document 1).

The tip is made of a flexible and elastic material to improve the insertability into the endoscope and into the biological duct, and is at the tip of the outer cylinder until the stent is delivered to the stenosis. It is necessary to keep it in place. After the stent reaches the stenosis, the outer cylinder is retracted with respect to the guide wire guide tube, so that the tip attached to the tip of the guide wire guide tube is disengaged from the outer cylinder, and then the stent with a reduced diameter is released. It is extruded from the outer cylinder, expanded in diameter, and detained.

The guide wire guide tube is made of a flexible resin material such as polyetheretherketone or polyimide. Further, the tip tip is made of a resin material such as a polyurethane-based elastomer or a polyamide-based elastomer having flexibility and elasticity in order to improve the insertability into the inside of the endoscope or the biological conduit.
The tip tip is generally bonded to the tip of the guide wire guide tube using an adhesive, but when bonding resin materials having these various functions to each other, depending on the type of resin material, Adhesion may be difficult (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2004-181230 Japanese Unexamined Patent Publication No. 11-076411

Therefore, in the present invention, even if the guide wire guide tube and the tip tip are not adhered, the state of being attached to the tip of the outer cylinder is maintained until the placement of the stent is started, and after the placement of the stent is started, the state is maintained. , An object of the present invention is to provide a tip that can be removed from an outer cylinder.

The present invention is a delivery system for indwelling a stent in a living body, in which an outer tube capable of accommodating the stent on the inside of the distal end side and an outer tube capable of advancing and retreating in the axial direction inside the outer tube are arranged and guided. It is composed of a guide wire guide tube through which a wire can be inserted and an elastic member having a tapered shape and flexibility whose outer diameter decreases toward the tip, and is attached to and detached from the outer cylinder so as to close the tip of the outer cylinder. The tip has a tip that can be attached, and the tip has a through hole formed so that the guide wire guide tube cannot be inserted and the guide wire can be inserted, and the outer cylinder is guided by the guide wire. The present invention relates to a stent delivery system in which the tip is relatively pushed toward the tip by the tip of the guide wire guide tube and is detached from the outer cylinder by retracting with respect to the tube.

Further, the tip has an enlarged diameter portion formed at least bifurcated on the base end side so as to have a shape that is wider than the inner diameter of the outer cylinder, and the enlarged diameter portion is the inner diameter of the outer cylinder. It is preferable that the outer cylinder is inserted into the end portion on the tip end side in a state of being narrowed to substantially the same diameter.

Further, the tip tip may be arranged on the outside of the outer cylinder so that a portion of the enlarged diameter portion having an outer diameter substantially the same as the outer diameter of the outer cylinder is continuous with the tip side of the outer cylinder. preferable.

Further, the inner cylinder is further provided inside the outer cylinder and outside the guide wire guide tube so as to be able to advance and retreat in the axial direction, and the stent can be pushed out from the outer cylinder at the end on the distal end side. , A first engagement provided at the distal end of the stent body with a stent body that is formed by braiding in a cylindrical shape with a fiber material and can be deformed from a reduced diameter state to an expanded state. A member, a second engaging member provided at an end portion of the stent body portion on the proximal end side and capable of engaging with the first engaging member, the first engaging member, and the guide wire guide. It has a string-shaped member that connects to the tube, and the stent main body has a shaft in a reduced diameter state by pulling the string-shaped member together with the guide wire guide tube toward the proximal end side. The diameter is expanded by contracting in the direction, the first engaging member and the second engaging member move in a direction close to each other, and the first engaging member and the second engaging member are brought together. It is preferable that they are engaged and maintained in an expanded state.

Further, the first engaging member is an annular member formed of a fiber material, and the second engaging member is a locking member formed of a fiber material and capable of locking the annular member. One end of the string-shaped member is connected to the locking member, extends to the distal end side of the stent body portion and is inserted into the annular member, and the other end extends to the proximal end side of the stent main body portion. It is preferably connected to the guide wire guide tube.

According to the delivery system of the present invention, the tip has a through hole formed so that the guide wire guide tube cannot be inserted and the guide wire can be inserted. Therefore, the tip is outside until the stent placement is started. The state of being attached to the tip of the cylinder is maintained, and after the stent is placed, the outer cylinder is retracted with respect to the guide wire guide tube, so that the tip of the tip is pushed toward the tip by the tip of the guide wire guide tube. The tip can be removed from the outer cylinder.

It is a schematic diagram which shows the state of the tip tip before stent placement in the stent delivery system which concerns on 1st Embodiment. FIG. 3 is a schematic view showing a state in which the outer cylinder is retracted from the state shown in FIG. 1A and the tip tip is removed from the outer cylinder. It is a schematic diagram which shows the state which the outer cylinder is further retracted from the state shown in FIG. 1B, and the stent is indwelled. It is a perspective view of the tip of the tip of the stent delivery system which concerns on 1st Embodiment. It is a perspective view which looked at the tip of the tip of the stent delivery system which concerns on 1st Embodiment from the bottom surface side. It is a perspective view which shows the stent before diameter expansion in 2nd Embodiment. It is a perspective view which shows the stent after diameter expansion in 2nd Embodiment. It is a figure which shows the operation of the diameter expansion mechanism of the stent in 2nd Embodiment, and is the side view before the diameter expansion of a stent. It is a figure which shows the state which the string-like member is pulled from the state shown in FIG. 4A, and the diameter of the stent main body is expanded. It is a figure which shows the state which pulls the string-like member further from the state shown in FIG. 4B, and locks a 1st engaging member (annular member) with a 2nd engaging member (locking member). It is a figure which shows the state which pulled the string-like member further from the state shown in FIG. 4C, and locked the first engaging member (annular member) with the second engaging member (locking member). It is a schematic diagram which shows the state of the tip tip before stent placement in the stent delivery system which concerns on 2nd Embodiment. FIG. 5 is a schematic view showing a state in which the outer cylinder is retracted from the state shown in FIG. 4A, the tip tip is removed from the outer cylinder, and the stent before diameter expansion is exposed from the outer cylinder. It is a schematic diagram which shows the state which advanced the inner cylinder from the state shown in FIG. 4B, retracted the guide wire guide tube, and placed the stent after the diameter expansion.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification, the hand side of the stent delivery system is the base end side, and the Y direction is shown in the figure. Further, the side opposite to the hand side of the stent delivery system is the tip side, and the X direction is shown in the figure.

<First Embodiment>
1A to 1C are schematic views showing a state of a tip tip when a stent is placed using the stent delivery system according to the first embodiment of the present invention. As shown in FIG. 1A, the stent delivery system 1A includes a stent 10A, an outer cylinder 20, a guide wire guide tube 30, a pusher 40A, and a tip tip 50.

The stent delivery system 1A has a length of 1 m to 2 m from the tip end to the base end, and the outer cylinder 20 and the guide wire guide tube 30 have a length corresponding to the length of the stent delivery system 1A.

As the stent 10A, any stent made of metal or resin is preferably used, but in the present embodiment, a metal stent having a self-expanding function is used. As a material for the metal stent, a titanium-nickel alloy having superelasticity or the like is preferably used.

The outer cylinder 20 houses the stent 10A inside the tip side (X direction side). The inner diameter of the outer cylinder 20 may be such that the stent 10A can be stored in a contracted (reduced diameter) state in the radial direction, and is preferably 2.8 mm to 3.2 mm, for example. The outer cylinder 20 is made of nylon with a metal blade woven inside, and PTFE (polytetrafluoroethylene) is used as an example for the innermost layer in contact with the stent 10A in order to improve slidability.

The guide wire guide tube 30 is formed with a through hole through which a guide wire 60, which will be described later, can be inserted, from the tip end to the base end. The guide wire guide tube 30 can be appropriately used in any material and inner / outer diameter as long as it can be arranged to move forward and backward inside the outer cylinder 20, but in the present embodiment, the outer diameter is 1.1 mm and the inner diameter is 1.1 mm. A material of 1.0 mm and a PEEK (polyetheretherketone) resin was used. Further, the tip end side (X direction side) of the guide wire guide tube 30 is arranged so as to abut on the proximal end side (Y direction side) of the tip tip 50 described later.

The pusher 40A is formed in a disk shape having a diameter corresponding to the inner diameter of the outer cylinder 20, and a through hole through which the guide wire guide pipe 30 is inserted is formed in the central portion. The pusher 40A is attached to the tip end side of the guide wire guide tube 30 so that the stent 10A can be pushed out from the outer cylinder 20. Further, the distal end side (X direction side) of the pusher 40A is arranged so as to abut on the proximal end side (Y direction side) of the stent 10A.
By moving the guide wire guide tube 30 to the tip side with respect to the outer cylinder 20, the pusher 40A attached to the tip side of the guide wire guide tube 30 also moves to the tip side, and the stent 10A is moved from the outer cylinder 20 to the tip side. Can be extruded.
As the material of the pusher 40A, it is sufficient that it has good slidability and a certain degree of hardness. Therefore, for example, a resin member such as nylon, polycarbonate or polyetheretherketone, or a metal member such as aluminum or SUS should be used. Can be done. In this embodiment, nylon is used.

As shown in FIG. 2A, the tip tip 50 has a tapered shape in which the outer diameter becomes smaller toward the tip, and is formed on the base end side in a shape that is at least bifurcated and widens larger than the inner diameter of the outer cylinder 20. The enlarged diameter portion 51 is formed. In the present embodiment, as shown in FIG. 2B, the tip tip 50 has a substantially conical shape in which a cone is cut out by a pyramid base so that the base end side has a bifurcated shape. The maximum diameter of the enlarged diameter portion 51 may be formed to be smaller than the diameter of the stent 10A after the enlarged diameter in order to facilitate recovery of the tip 50.
Further, the tip tip 50 is formed with a through hole having a diameter smaller than the outer diameter of the guide wire guide tube 30 and larger than the outer diameter of the guide wire 60 described later, and the guide wire guide tube 30 cannot be inserted. Moreover, the guide wire 60 can be inserted therethrough.

As the material constituting the tip chip 50, an elastic member having biocompatibility and flexibility is used, and more specifically, a thermoplastic elastomer such as a polyurethane elastomer, a polyamide elastomer, or a polystyrene elastomer is preferably used. In this embodiment, the polystyrene-based elastomer Arneston (registered trademark) CJ001N was used.

As shown in FIG. 1A, the tip tip 50 is inserted into the tip end of the outer cylinder 20 in a state where the enlarged diameter portion 51 is reduced to substantially the same diameter as the inner diameter of the outer cylinder 20, and the tip of the outer cylinder 20 is inserted. It is detachably attached to the outer cylinder 20 so as to close the outer cylinder 20. Since the tip 50 has flexibility and elasticity, it is supported by the inner wall of the outer cylinder 20 in the enlarged diameter portion 51.
Further, the tip tip 50 is arranged outside the outer cylinder 20 so that a portion of the enlarged diameter portion 51 having an outer diameter substantially the same as the outer diameter of the outer cylinder 20 is continuous (adjacent) to the tip of the outer cylinder 20. Therefore, it is possible to make it difficult for a step corresponding to the wall thickness of the outer cylinder 20 to occur between the tip of the outer cylinder 20 and the tip tip 50.

The guide wire 60 guides the stent delivery system 1A to be inserted into the body. After the guide wire 60 reaches the site where the stent 10A is placed, the stent delivery system 1A is inserted into the body with the tip tip 50 attached to the tip of the outer cylinder 20 to bring the stent 10A to the target site. Can be carried.

Subsequently, with reference to FIGS. 1A to 1C, a method of placing the stent 10A in the constricted portion N in the living body by using the stent delivery system 1A will be described.

The stent delivery system 1A in which the stent 10A is housed inside the outer cylinder 20 is inserted into the forceps opening of an endoscope (not shown). Subsequently, as shown in FIG. 1A, the stent delivery system 1A is arranged so that the tip end side is located in the vicinity of the narrowed portion N in a state where the tip tip 50 is attached to the tip end of the outer cylinder 20.

Subsequently, from the state of FIG. 1A, the outer cylinder 20 is moved to the base end side (Y direction side) with the guide wire guide pipe 30 fixed, that is, by retracting the guide wire guide tube 30 as shown in FIG. 1B. The tip tip 50 is removed from the outer cylinder 20 by being relatively pushed toward the tip side by the wire guide tube 30, and the enlarged diameter portion 51 is opened from the narrowed state.

Subsequently, from the state of FIG. 1B, the outer cylinder 20 is further retracted with the guide wire guide pipe 30 fixed, so that the pusher 40A attached to the guide wire guide pipe 30 is relative to the state as shown in FIG. 1C. The stent 10A is pushed out from the outer cylinder 20 and placed in the narrowed portion N by being pushed toward the distal end side. The stent 10A having a self-expanding function expands in diameter at the narrowed portion N to prevent restenosis.

According to the stent delivery system 1A according to the first embodiment, the following effects are achieved.
(1) In the first embodiment, an outer cylinder 20 that can store the stent 10A in a reduced diameter inside the tip side and an outer cylinder 20 that can be moved forward and backward in the axial direction inside the outer cylinder 20 and the guide wire 60 is inserted. It is composed of a possible guide wire guide tube 30, a tapered shape whose outer diameter decreases toward the tip, and a flexible elastic member, and can be attached to and detached from the outer cylinder 20 so as to close the tip of the outer cylinder 20. The tip tip 50 is provided with a tip tip 50 to be attached, and the tip tip 50 has a through hole formed so that the guide wire guide tube 30 cannot be inserted and the guide wire 60 can be inserted. As a result, the tip 50 is kept attached to the tip of the outer cylinder 20 until the placement of the stent 10A is started. When the outer cylinder 20 is retracted with respect to the guide wire guide tube 30 in order to place the stent 10A in the narrowed portion N, the tip tip 50 is relatively pushed toward the tip side by the tip of the guide wire guide tube 30 to the outside. Since it is detached from the cylinder 20, the tip tip 50 can be attached to the outer cylinder 20 with a simple configuration without bonding the guide wire guide tube 30 and the tip tip 50.

(2) In the first embodiment, the tip tip 50 has an enlarged diameter portion 51 formed on the base end side in a shape that is at least bifurcated and is formed in a shape that is wider than the inner diameter of the outer cylinder 20. It is assumed that 51 is inserted into the end portion on the tip side of the outer cylinder 20 in a state where the diameter is narrowed to substantially the same diameter as the inner diameter of the outer cylinder 20. As a result, the enlarged diameter portion 51 of the tip tip 50 is supported by the inner wall of the outer cylinder 20, and the tip tip 50 is detachably attached to the outer cylinder 20.

(3) In the first embodiment, the tip tip 50 is outside the outer cylinder 20 so that a portion of the enlarged diameter portion 51 having an outer diameter substantially the same as the outer diameter of the outer cylinder 20 is continuous with the tip of the outer cylinder 20. It was supposed to be placed in. As a result, it is possible to make it difficult for a step corresponding to the wall thickness of the outer cylinder 20 to occur between the tip of the outer cylinder 20 and the tip tip 50, so that the stent delivery system 1A is inserted into the living body along the guide wire 60. When doing so, it is difficult to damage the inside of the living body, and the insertion resistance can be reduced in the narrowed portion N.

<Second Embodiment>
Next, a second embodiment of the present invention will be described. The present embodiment is different from the first embodiment in that a non-self-expandable stent is used as the stent and an inner cylinder is further provided between the outer cylinder and the guide wire guide tube. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

3A and 3B are perspective views of the stent 10B used in this embodiment. 4A-4D are diagrams showing the operation of the diameter expansion mechanism of the stent 10B. 5A to 5C are schematic views for explaining a method of placing the stent 10B in the constricted portion.

First, the configuration of the stent 10B used in the stent delivery system 1B will be described with reference to FIGS. 3A and 3B.
As shown in FIGS. 3A and 3B, the stent 10B includes a stent body 110 and a diameter expanding mechanism 120.

The stent body 110 is formed in a cylindrical shape by the biodegradable fiber material 111. More specifically, the stent main body 110 is woven in a mesh pattern with a plurality of fiber materials 111, and has a large number of rhombic pores formed by the fiber materials 111 on the outer periphery and regularly arranged.

Examples of the biodegradable fiber material 111 include monomers such as L-lactic acid, D-lactic acid, DL-lactic acid, ε-caprolactone, γ-butyrolactone, δ-valerolactone, glycolic acid, trimethylene carbonate, and paradioxanone. Examples include homopolymers, copolymers, and blended polymers thereof synthesized from.
The fiber material 111 may be a monofilament yarn or a multifilament yarn. Further, the fiber material 111 may or may not be twisted.

The diameter of the fiber material 111 is preferably 0.05 to 0.7 mm. If the diameter of the fiber material 111 is less than 0.05 mm, the strength of the stent 10B tends to decrease. If the diameter of the fiber material 111 exceeds 0.7 mm, it tends to be difficult to store the stent 10B in the outer cylinder 20B. The upper limit of the diameter of the fiber material 111 is more preferably 0.4 mm and further preferably 0.3 mm from the viewpoint of being housed in the delivery system of the outer cylinder having a smaller inner diameter. The lower limit of the diameter of the fiber material 111 is more preferably 0.2 mm from the viewpoint of maintaining high strength.

The diameter expanding mechanism 120 includes an annular member 121 as a first engaging member, a locking member 122 as a second engaging member, and a string-shaped member 123. Since the fiber material 111 is made of synthetic resin or the like, it may not have sufficient strength as a stent as compared with a metal stent. Therefore, it is preferable to increase the density and give strength by shortening the stent in the axial direction by using the diameter expanding mechanism 120.

The annular member 121 is provided at the distal end side (X direction side) of the stent main body 110. The annular member 121 is made of synthetic resin fibers, and is formed in an annular shape by connecting both ends of the synthetic resin fibers to the fiber material 111 constituting the stent main body 110. The synthetic resin fiber constituting the annular member 121 may be the same material as the fiber material 111 constituting the stent main body 110, or may be different.

The locking member 122 is arranged at the end portion of the stent main body 110 on the proximal end side (Y direction side), and is configured to engage with the annular member 121 to lock the annular member 121. In the present embodiment, as shown in FIG. 5A, the locking member 122 is formed by forming the fiber material 111 constituting the stent main body 110 in a loop shape. The locking member 122 may be formed of a synthetic resin fiber other than the fiber material 111.

The string-shaped member 123 connects the first engaging member (annular member) 121 and the guide wire guide pipe 30. Specifically, one end of the string-shaped member 123 is connected to the second engaging member (locking member) 122, extends to the distal end side (X direction side) of the stent main body 110, and is inserted into the annular member 121. Then, the other end extends to the proximal end side (Y direction side) of the stent main body 110 and is connected to the guide wire guide tube 30.

The base end portion of the locking member 122 to which the string-shaped member 123 is connected is made of the fiber material 111 so that one end of the tied string-shaped member 123 does not move to the stent main body 110 side (X direction side). It is preferable to fix the intersection.

A plurality of the above-mentioned diameter expanding mechanisms 120 are arranged at equal intervals in the circumferential direction of the stent main body 110. In this embodiment, as shown in FIGS. 3A and 3B, two diameter expansion mechanisms 120 are arranged.

According to the above-mentioned diameter expanding mechanism 120, in a state where the diameter of the stent main body 110 is reduced, the string-shaped member 123 is pulled toward the proximal end side (Y direction side) of the stent main body 110 to engage with the annular member 121. As the member 122 moves in the approaching direction, the annular member 121 and the locking member 122 engage with each other to maintain the stent body 110 in an enlarged diameter state.

Next, the operation of the diameter expanding mechanism 120 will be described with reference to FIGS. 4A to 4D.

In the stent 10B, when the other end side of the string-shaped member 123 is pulled toward the proximal end side (Y direction side) of the stent main body 110, the annular member 121 through which the string-shaped member 123 is inserted is inserted into the stent main body portion by the string-shaped member 123. By being pulled toward the proximal end side of the 110, the annular member 121 and the locking member 122 move in a direction close to each other.

Next, when the string-shaped member 123 is further pulled toward the proximal end side (Y direction) of the stent main body 110, the annular member 121 gets over the locking member 122 formed in a loop shape, as shown in FIG. 4C. The annular member 121 that has passed over the locking member 122 is pulled toward the tip end side (X direction) by the restoring force (force that tends to extend in the axial direction) of the stent main body 110 and is locked to the locking member 122. As a result, the stent main body 110 is maintained in an expanded state.

The stent delivery system 1B according to the present embodiment will be described with reference to FIGS. 5A to 5C. The stent delivery system 1B includes the above-mentioned stent 10B, an outer cylinder 20, a guide wire guide tube 30, an inner cylinder 40B, and a tip tip 50.

The inner cylinder 40B is arranged inside the outer cylinder 20 so as to be able to advance and retreat in the axial direction. The tip end portion (X direction end portion) of the inner cylinder 40B is arranged on the proximal end side (Y direction side) of the stent 10B, and the inner cylinder 40B is moved (advanced) to the tip end side with respect to the outer cylinder 20. , The stent 10B can be extruded from the outer cylinder 20. Further, inside the inner cylinder 40B, a guide wire guide pipe 30 is arranged so as to be able to advance and retreat in the axial direction.
Since the inner cylinder 40B can be stored in the outer cylinder 20, the outer diameter is smaller than the inner diameter of the outer cylinder 20, and the inner diameter is outside the guide wire guide pipe 30 because the guide wire guide pipe 30 can be stored. It is configured to be larger than the diameter. Further, as the inner cylinder 40B, a material having a small resistance when it comes into contact with the outer cylinder 20 and the guide wire guide tube 30 is used among the flexible synthetic resins.

Subsequently, with reference to FIGS. 5A to 5C, a method of placing the stent 10B in the constricted portion N in the living body by using the stent delivery system 1B will be described.

The stent delivery system 1B in which the stent 10B is housed inside the outer cylinder 20 is inserted into the forceps opening of an endoscope (not shown). Subsequently, as shown in FIG. 5A, the stent delivery system 1B is arranged so that the tip end side is located in the vicinity of the narrowed portion N with the tip tip 50 attached to the tip end of the outer cylinder 20.

Subsequently, from the state of FIG. 5A, the outer cylinder 20 is moved to the base end side (Y direction side) with the guide wire guide pipe 30 and the inner cylinder 40B fixed, that is, by relatively retracting. As shown in FIG. 5B, the tip tip 50 is relatively pushed toward the tip side by the guide wire guide tube 30 and removed from the outer cylinder 20, and the enlarged diameter portion 51 is opened from the squeezed state. .. A part of the distal end side of the stent 10B is exposed from the outer cylinder 20.

Subsequently, from the state of FIG. 5B, with the outer cylinder 20 fixed, the guide wire guide pipe 30 is retracted and the inner cylinder 40B is moved to the tip side (X direction side), that is, the inner cylinder 40B is advanced. Let me. Then, as shown in FIG. 5C, the stent 10B was pushed out to the distal end side by the inner cylinder 40B, and the guide wire guide tube 30 was pulled toward the proximal end side to the inside of the stent 10B and connected to the guide wire guide tube 30. The string-shaped member 123 is pulled toward the proximal end side, the diameter of the stent 10B is expanded, and the diameter expansion state is maintained by the diameter expansion mechanism 120. In this way, the stent 10B can be placed by the stent delivery system 1B. The stent 10B whose diameter is expanded by the diameter expanding mechanism 120 and has sufficient strength can prevent the stenotic portion N from restenosis. Further, after the stent 10B is placed in the narrowed portion N, the string-shaped member 123 is cut at a predetermined position, and the stent delivery system 1B is taken out of the body.

According to the stent delivery system 1B according to the second embodiment, the following effects are exhibited in addition to the above-mentioned effects (1) to (3).
(4) In the second embodiment, the stent delivery system 1B in which the stent 10B provided with the diameter expanding mechanism 120 is placed in the living body connects the outer cylinder 20, the first engaging member 121, and the guide wire guide tube 30. A string-shaped member 123, an inner cylinder 40B for extruding the stent 10B, and a tip tip 50 are provided, and the tip tip 50 is formed so that the guide wire guide tube 30 cannot be inserted and the guide wire 60 can be inserted. It was assumed to have a hole. As a result, when the stent 10B is placed, it is necessary to pull the guide wire guide tube 30 to the inside of the stent 10B toward the proximal end side, but since the guide wire guide tube 30 and the tip tip 50 are not adhered to each other, the tip The guide wire guide tube 30 can be pulled toward the proximal end side without being interfered by the tip 50, and the stent 10B can be placed.

Although the preferred embodiments of the stent delivery system of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be appropriately modified.
For example, in the above-described embodiment, a configuration in which the tip tip is bifurcated on the proximal end side is shown as an example, but the present invention is not limited to this. The tip tip may have any structure as long as it can be detachably attached to the tip of the outer cylinder. For example, the tip may have a shape in which the base end side is divided into three or four forks.

Further, in the first embodiment, a self-expandable metal stent is used as the stent 10A, but the present invention is not limited to this, and a balloon-expandable metal stent that is not self-expandable or a stent formed of synthetic resin is used. May be good.

Further, in the second embodiment, a biodegradable stent composed of biodegradable fibers is used as the stent, but the stent is not limited to this. That is, the stent may be constructed using synthetic resin fibers that do not have biodegradability, and can also be applied to a metal stent that is not a shape memory alloy, that is, has no self-expanding ability. is there.

Further, in the second embodiment, an annular member is shown as an example of the first engaging member, and a locking member is shown as an example of the second engaging member, but the present invention is not limited to this. Any configuration can be applied as long as the first engaging member and the second engaging member can be engaged with each other.

1A, 1B Stent Delivery System 10A, 10B Stent 20 Outer Cylinder 30 Guide Wire Guide Tube 40A Pusher 40B Inner Cylinder 50 Tip Tip N Stenosis

Claims (5)

A delivery system for placing a stent in vivo.
An outer cylinder that can store the stent in a reduced diameter inside the tip side,
A guide wire guide tube that is arranged inside the outer cylinder so that it can move forward and backward in the axial direction and through which a guide wire can be inserted,
A tip tip that has a tapered shape with an outer diameter that decreases toward the tip and is made of a flexible elastic member and is detachably attached to the outer cylinder so as to close the tip of the outer cylinder.
With
The guide wire guide tube and the tip tip are not adhered to each other and can move relatively.
The tip has a through hole formed so that the guide wire guide tube cannot be inserted and the guide wire can be inserted, and the guide is retracted with respect to the guide wire guide tube. A stent delivery system in which the tip tip is relatively pushed toward the tip side by the tip of a wire guide tube to be removed from the outer cylinder. The tip has an enlarged diameter portion formed at least bifurcated on the base end side and formed in a shape that is wider than the inner diameter of the outer cylinder, and the enlarged diameter portion is substantially the same as the inner diameter of the outer cylinder. The stent delivery system according to claim 1, wherein the stent delivery system is inserted into the distal end portion of the outer cylinder in a state of being narrowed to a diameter. According to claim 2, the tip tip is arranged on the outside of the outer cylinder so that a portion of the enlarged diameter portion having an outer diameter substantially the same as the outer diameter of the outer cylinder is continuous with the tip side of the outer cylinder. The stent delivery system described. An inner cylinder is further provided inside the outer cylinder and outside the guide wire guide tube so as to be axially reciprocating and capable of pushing the stent out of the outer cylinder at the distal end.
The stent is
A stent body that is formed by knitting into a cylindrical shape with a fiber material and can be deformed from a reduced diameter state to an expanded state.
A first engaging member provided at the distal end of the stent body and
A second engaging member provided at the proximal end side of the stent body and capable of engaging with the first engaging member.
It has a string-shaped member that connects the first engaging member and the guide wire guide tube.
In a reduced diameter state, the strap-shaped member is pulled toward the proximal end side together with the guide wire guide tube, so that the stent main body contracts in the axial direction and the diameter is expanded, and the first engagement is performed. A claim in which the combined member and the second engaging member move in a direction close to each other, and the first engaging member and the second engaging member are engaged with each other to maintain an enlarged diameter. Item 4. The stent delivery system according to any one of Items 1 to 3. The first engaging member is an annular member formed of a fiber material.
The second engaging member is a locking member formed of a fiber material and capable of locking the annular member.
One end of the string-shaped member is connected to the locking member, extends to the distal end side of the stent body portion and is inserted into the annular member, and the other end extends to the proximal end side of the stent main body portion to guide the guide. The stent delivery system according to claim 4, which is connected to a wire guide tube.

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