Stent Delivery System

Abstract

To provide a stent delivery system that allows for the withdrawal of a stent even with a small outer diameter, prevents accidental disconnection of the connection between the stent and the pusher catheter, and allows for easy disconnection when desired. [Solution] The stent delivery system 100 has a tube stent 10 with a small inner diameter portion 12 on its proximal end, and a pusher catheter 20 that can contact the end face of the small inner diameter portion 12 has a hole provided in the radial direction and a thread-like body with a knot-like structure. The small inner diameter portion 12 has a hooking hole provided in the radial direction and an inner diameter smaller than the sum of the longest dimension of the knot-like structure and the outer diameter of the guide wire 30. The thread-like body and the knot-like structure are inserted into the small inner diameter portion 12, and the guide wire 30 is inserted into the pusher catheter 20 and the small inner diameter portion 12 with the knot-like structure loosely fitted in the hooking hole.

Description

Technical Field

[0001] The present invention relates to a stent delivery system using a catheter, and particularly to one using a plastic tube stent (hereinafter sometimes simply referred to as a "stent") such as polyethylene or polyurethane.

Background Art

[0002] Among the stents used in stent placement, the tube stent advances inside the human body by being pushed by a pusher catheter along a guide wire or an inner catheter inserted into the human body. Conventionally, the tube stent can only be pushed by a pusher catheter and cannot be pulled back. If the positioning of the stent is incorrect, the stent has to be removed and redone. Therefore, delivery systems that can pull back the stent have been developed.

[0003] The applicant of the present invention has developed a stent delivery system that can pull back the stent, has a simple structure, is unlikely to accidentally release the connection state between the stent and the pusher catheter, and is easy to release when the connection state needs to be released, and has patent rights related to the following publications.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the stent delivery system described in Patent Document 1, the pusher catheter has a hole for attaching a thread-like body to its end, and the stent has a hooking hole. The knob-like body provided on the thread-like body is loosely fitted into the hooking hole from the inside of the stent, and this loose fit is maintained by the inner catheter inserted inside the stent. Therefore, the connection between the stent and the pusher catheter is not easily released unintentionally until the inner catheter is withdrawn. When the inner catheter is withdrawn, the knob-like body comes out of the hooking hole, and the connection between the stent and the pusher catheter is easily released.

[0006] Incidentally, by reducing the outer diameter of a stent, it becomes easier for it to advance within the human body and the number of treatable areas can be increased. Therefore, in recent years, stents with smaller outer diameters have been developed. Stents with an outer diameter of less than 5 Fr (French) can be called ultra-fine stents, and stents with an outer diameter of 3 Fr or less, i.e., less than 1 mm, have also appeared. However, stents with smaller outer diameters also have smaller diameters of their internal communication holes (hereinafter referred to as "inner diameter"). In this case, although it is possible to pass a guidewire through the inside of the stent, it is not possible to pass an inner catheter between the inner diameter of the stent and the guidewire, which presents the problem that the stent delivery system described above cannot be applied.

[0007] Therefore, the object of the present invention is to provide a stent delivery system that allows a stent to be withdrawn even if it has a small outer diameter, makes it difficult for the connection between the stent and the pusher catheter to be accidentally released, and makes it easy to release the connection when desired. [Means for solving the problem]

[0008] The present invention comprises a guide wire, a cylindrical tube stent, and a pusher catheter. The tube stent has a small inner diameter portion at its proximal end, The pusher catheter, which can contact the end face of the inner diameter small portion, has a hole provided in the radial direction and a thread-like body having a knot-like structure that is attached using the hole. The aforementioned small-diameter inner portion has an inner diameter that is larger than the longest dimension of the knob-shaped body and smaller than the sum of the longest dimension and the outer diameter of the guide wire, and is provided with a hooking hole in the radial direction. With the filamentous body and the knotted body inserted into the small inner diameter portion, and with the knotted body loosely fitted in the locking hole, the guide wire is inserted into the pusher catheter and the small inner diameter portion. A stent delivery system characterized in that the guide wire maintains a loose fit between the knob-shaped body and the locking hole. Or, It has a guide wire, a cylindrical tube stent, and a pusher catheter. The pusher catheter has a small inner diameter portion at its tip, The tube stent, which can contact the end face of the inner diameter small portion, has a hole provided in the radial direction and a thread-like body having a knot-like structure that is attached using the hole, The aforementioned small-diameter inner portion has an inner diameter that is larger than the longest dimension of the knob-shaped body and smaller than the sum of the longest dimension and the outer diameter of the guide wire, and is provided with a hooking hole in the radial direction. With the filamentous body and the knotted body inserted into the small inner diameter portion, and with the knotted body loosely fitted in the locking hole, the guide wire is inserted into the small inner diameter portion and the tube stent. The above problem was solved by a stent delivery system characterized in that the guide wire maintains a loosely fitted state between the knob-shaped body and the locking hole. [Effects of the Invention]

[0009] According to the present invention, a tube stent has a small inner diameter portion at its proximal end, and a pusher catheter that can contact the end face of the small inner diameter portion has a hole provided in the radial direction and a thread-like body with a knot-like structure that is attached using the hole. The small inner diameter portion has a hooking hole provided in the radial direction and an inner diameter that is larger than the longest dimension of the knot-like structure and smaller than the sum of the longest dimension of the knot-like structure and the outer diameter of the guide wire. Furthermore, when the thread-like body and the knot-like structure are inserted into the small inner diameter portion and the knot-like structure is loosely fitted with the hooking hole, the guide wire is inserted into the pusher catheter and the small inner diameter portion, and the guide wire maintains the loose fit between the knot-like structure and the hooking hole. Therefore, even with an extremely thin stent that cannot pass through the inner catheter, the stent can be pulled back, the connection between the stent and the pusher catheter is difficult to accidentally release, and the connection can be easily released when desired, providing a stent delivery system.

[0010] Furthermore, the stent delivery system may be configured such that the pusher catheter has a small inner diameter section at its tip, and the tube stent, which can contact the end face of the small inner diameter section, has a radially provided hole and a thread-like body with a knob-like structure that is attached using the hole. With this configuration, when removing the stent after placement, the thread-like body is easy to grasp with forceps or the like, making it easier to remove the stent. [Brief explanation of the drawing]

[0011] [Figure 1] A side view of a first embodiment of the stent delivery system of the present invention. [Figure 2] Enlarged cross-sectional view of the main part shown in Figure 1. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below with reference to Figures 1 and 2. However, the present invention is not limited to these embodiments.

[0013] The stent delivery system 100 of the present invention, shown in Figure 1, comprises a tubular stent (stent) 10, a pusher catheter 20, and a guide wire 30. The stent 10 and the pusher catheter 20 are cylindrical in shape. The stent 10 can be made of plastic such as polyethylene or polyurethane, and the pusher catheter 20 can be made of fluororesin such as PTFE (polytetrafluoroethylene). The guide wire 30 is a wire mainly made of metal with a coating on its surface. The stent 10, the pusher catheter 20, and the guide wire 30 are inserted into an endoscope (not shown) for use.

[0014] The outer diameter of the stent 10 can be any diameter, but the stent delivery system 100 of the present invention is also applicable to ultra-fine stents with an outer diameter of less than 5 Fr. The tip end of the stent 10 may have a tapered portion 15 that narrows towards the tip. The outer diameter of the pusher catheter 20 should be such that the end face on the proximal end of the stent 10 and the end face on the tip end of the pusher catheter 20 can come into contact. The guide wire 30 is inserted through the pusher catheter 20 so as to penetrate its interior, and is inserted into the stent 10. Therefore, the outer diameter of the guide wire 30 should be such that it can pass through the interior of both the stent 10 and the pusher catheter 20.

[0015] The stent 10 has a small inner diameter portion 12 at its base end. The small inner diameter portion 12 is the part of the stent 10 where the inner diameter is formed to be small. The small inner diameter portion 12 of the stent 10 can be formed by manufacturing a stent 10 with the same inner diameter as the small inner diameter portion 12, inserting a jig into the inside of the stent 10 and stretching the tip side of the stent 10, or by manufacturing a small inner diameter portion 12 and a stent 10 located beyond the small inner diameter portion 12 separately, and then welding them together.

[0016] The stent delivery system 100 is provided with a connecting mechanism 50 for connecting the stent 10 and the pusher catheter 20 by utilizing the small-diameter inner diameter portion 12 of the stent 10. The connecting mechanism 50 will be described in detail below.

[0017] FIG. 2 is an enlarged cross-sectional view of the main part of the stent delivery system 100. As shown in FIG. 2, a small-diameter inner diameter portion 12 is provided on the proximal end side of the stent 10. The small-diameter inner diameter portion 12 has an inner diameter that is larger than the longest dimension of the knob-shaped body 54 of the connecting mechanism 50 and smaller than the sum of the longest dimension of the knob-shaped body 54 and the outer diameter of the guide wire 30. Further, a latching hole 14 is provided in the small-diameter inner diameter portion 12 in the radial direction. The latching hole 14 may be a through hole or a non-through hole, and is provided with a size that allows the knob-shaped body 54 to be loosely fitted.

[0018] On the other hand, a hole 22 is provided in the pusher catheter 20 in the radial direction thereof. The hole 22 is provided with a size that allows a filament body 52, which will be described later, to be inserted therethrough, and it is preferably provided on the distal end side of the pusher catheter 20 in order to prevent the filament body 52 from becoming overly long.

[0019] The filament body 52 of the connecting mechanism 50 is passed through the hole 22. Although illustration for explanation is omitted, the filament body 52 may be attached to the pusher catheter 20 by passing the filament body 52 through the hole 22, tying a knot, and securing the knot. Further, the filament body 52 has a knob-shaped body 54. The knob-shaped body 54 may be formed by tying the filament body 52, or may be provided by welding a sphere.

[0020] As shown in the figure, the filamentous body 52 and the knob-shaped body 54 attached to the pusher catheter 20 are inserted into the small-diameter inner portion 12 of the stent 10, and the knob-shaped body 54 is loosely fitted into the locking hole 14. The guide wire 30 is then inserted into the pusher catheter 20, the small-diameter inner portion 12 of the stent 10, and the inside of the stent 10. This maintains the loose fit between the knob-shaped body 54 and the locking hole 14. Note that in Figure 2, for the sake of explanation, the sizes of the small-diameter inner portion 12 of the stent 10, the pusher catheter 20, the guide wire 30, and the knob-shaped body 54 are exaggerated.

[0021] The stent delivery system 100 has the above configuration, so when the stent 10 is placed in the body, the stent 10 can be pulled back by pulling the pusher catheter 20. At that time, the guide wire 30 maintains a loose fit between the knob-shaped body 54 and the locking hole 14, so the connection between the stent 10 and the pusher catheter 20 is not easily released unintentionally. Furthermore, when it is desired to release the connection between the stent 10 and the pusher catheter 20, the guide wire 30 is pulled out, causing the knob-shaped body 54 to move into the small-diameter inner portion 12 of the stent 10, and the connection between the stent 10 and the pusher catheter 20 is released. Therefore, a stent delivery system that makes it easy to release the connection between the stent 10 and the pusher catheter 20 can be provided. In particular, the stent delivery system 100 can be applied to ultra-fine stents with an outer diameter of less than 5 Fr that cannot be passed through an inner catheter.

[0022] Furthermore, as shown in the figure, the filamentous body 52 may be configured to have an extension portion 56 that extends beyond the locking hole 14 when viewed from the pusher catheter 20. With this configuration, the filamentous body 52 and the extension portion 56 are sandwiched between the small inner diameter portion 12 of the stent 10 and the guide wire 30 before and after the locking hole 14, so that the knot-like body 54 does not completely protrude outside the locking hole 14 of the stent 10. Moreover, when the guide wire 30 is withdrawn, the knot-like body 54 naturally tries to move inside the small inner diameter portion 12 of the stent 10, so that the connection between the stent 10 and the pusher catheter 20 can be reliably and easily released.

[0023] Although a diagrammatic explanation is omitted, the basic configuration is the same as that of the stent delivery system 100, with the inner diameter small diameter portion 12 and the hooking hole 14 provided on the tip side of the pusher catheter 20, and the hole 22 provided on the proximal end side of the stent 10, and the thread-like body 52 having a knob-like body 54 attached using the hole 22. In other words, the configuration can be such that the reference numeral 20 in Figure 2 represents the stent and the reference numeral 10 represents the pusher catheter. With this configuration, when removing the stent 10 after placement, the thread-like body 52 is easy to grasp with forceps or the like, making it easier to remove the stent 10.

[0024] As described above, the present invention provides a stent delivery system that allows even a stent with a small outer diameter to be retracted, makes it difficult for the connection between the stent and the pusher catheter to be unintentionally released, and makes it easy to release the connection when desired. [Explanation of symbols]

[0025] 10 Tube Stent 12. Small diameter section of the inner diameter 14 Latch hole 20 Pusher Catheter 22 holes 30 guide wires 52 Filamentous bodies 54. Nodular body 100 Stent Delivery System

Claims

1. It has a guide wire, a cylindrical tube stent, and a pusher catheter. The tube stent has a small inner diameter portion at its proximal end, The pusher catheter, which can contact the end face of the inner diameter small portion, has a hole provided in the radial direction and a thread-like body having a knot-like structure that is attached using the hole. The aforementioned small-diameter inner portion has an inner diameter that is larger than the longest dimension of the knob-shaped body and smaller than the sum of the longest dimension and the outer diameter of the guide wire, and is provided with a hooking hole in the radial direction. With the filamentous body and the knotted body inserted into the small inner diameter portion, and with the knotted body loosely fitted in the locking hole, the guide wire is inserted into the pusher catheter and the small inner diameter portion. The guide wire is characterized by maintaining a loose fit between the knob-shaped body and the locking hole. Stent delivery system.

2. It has a guide wire, a cylindrical tube stent, and a pusher catheter. The pusher catheter has a small inner diameter portion at its tip, The tube stent, which can contact the end face of the inner diameter small portion, has a hole provided in the radial direction and a thread-like body having a knot-like structure that is attached using the hole, The aforementioned small-diameter inner portion has an inner diameter that is larger than the longest dimension of the knob-shaped body and smaller than the sum of the longest dimension and the outer diameter of the guide wire, and is provided with a hooking hole in the radial direction. With the filamentous body and the knotted body inserted into the small inner diameter portion, and with the knotted body loosely fitted in the locking hole, the guide wire is inserted into the small inner diameter portion and the tube stent. The guide wire is characterized by maintaining a loose fit between the knob-shaped body and the locking hole. Stent delivery system.

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