Delivery system

Abstract

This provides a delivery system that is advantageous in reducing the withdrawal resistance of the inner catheter. [Solution] The device comprises an inner catheter 22, an outer catheter 24 through which the inner catheter 22 passes and through which a first side hole 24b is formed, a tube stent 10 positioned distal to the outer catheter 24 and through which the inner catheter 22 passes, and a first filamentous member 16 irrevocably connected to the tube stent 10, the first filamentous member 16 having at least a portion on the proximal end side of the first side hole 24b that passes between the inner catheter 22 and the outer catheter 24, wherein the first filamentous member 16 passes through the first side hole 24b and is positioned outside the outer catheter 24 in at least a portion of the axial range R from the tip of the outer catheter 24 to the first side hole 24b.

Description

Technical Field

[0001] The present disclosure relates to a delivery system.

Background Art

[0002] Patent Document 1 discloses a delivery system for delivering a tube stent. This delivery system includes an inner catheter, an outer catheter through which the inner catheter is passed and a first side hole is formed, and a tube stent disposed on the distal end side with respect to the outer catheter through which the inner catheter is passed. The delivery system of Patent Document 1 includes a first filamentary member connected to the tube stent. This first filamentary member is passed between the inner catheter and the outer catheter on both axial sides with respect to the first side hole.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the inner catheter is pulled out toward the proximal end side with respect to the outer catheter, a pulling resistance is generated in the inner catheter due to friction with the first filamentary member. The inventor of the present application has recognized that there is room for improvement in reducing the pulling resistance of the inner catheter with respect to the delivery system of Patent Document 1.

[0005] Therefore, one object of the present disclosure is to provide a delivery system advantageous for reducing the pulling resistance of the inner catheter.

Means for Solving the Problems

[0006] The delivery system of this disclosure comprises an inner catheter, an outer catheter through which the inner catheter is passed and through which a first side hole is formed, a tubular stent positioned distal to the outer catheter and through which the inner catheter is passed, and a first filamentous member irrevocably connected to the tubular stent, the first filamentous member having at least a portion on the proximal end side of the first side hole that passes between the inner catheter and the outer catheter, wherein the first filamentous member passes through the first side hole and is positioned outside the outer catheter in at least a portion of the axial range from the tip of the outer catheter to the first side hole. [Effects of the Invention]

[0007] According to this disclosure, it is advantageous to reduce the withdrawal resistance of the inner catheter. [Brief explanation of the drawing]

[0008] [Figure 1] This is an explanatory diagram illustrating an example of the use of a tube stent. [Figure 2] This is a side view of the delivery system according to the first embodiment. [Figure 3] This is a schematic diagram showing an enlarged portion of Figure 2. [Figure 4] This is a schematic side cross-sectional view showing the first filamentous member of the first embodiment together with the surrounding structure. [Figure 5] This is a view of a part of the delivery system from the direction of arrow V in Figure 4. [Figure 6] This is a schematic side cross-sectional view showing the second filamentous member of the first embodiment together with the surrounding structure. [Figure 7] This is a schematic diagram illustrating the operation when releasing the connection by the second thread-like member. [Figure 8] This is a schematic side cross-sectional view showing the first filamentous member of the second embodiment together with the surrounding structure. [Modes for carrying out the invention]

[0009] Embodiments for implementing the delivery system of this disclosure are described below. Identical or equivalent elements are denoted by the same reference numerals, and redundant explanations are omitted. For the sake of clarity, components are omitted, enlarged, or reduced as appropriate in each drawing. Drawings should be viewed in accordance with the orientation of the reference numerals. In this specification, the notation "first," "second," etc., "nth" (where n is a natural number) is used solely as a formal description to distinguish multiple elements and has no other substantive meaning. For example, each element denoted as "nth" may exist independently without continuity. The "second" element may exist without the "first" element existing.

[0010] (First Embodiment) Refer to Figure 1. First, the usage scenarios of the tube stent 10 used in the delivery system will be explained. The tube stent 10 is used for the purpose of performing actions related to the treatment or examination of living organisms (hereinafter referred to as "procedures"). The tube stent 10 in this embodiment is used for drainage such as bile duct drainage and pancreatic duct drainage.

[0011] In a living organism, there is a first organ 12 that is the target of treatment, and a second organ 14 through which the entrance 12a of the first organ 12 opens. Here, we will explain an example where the first organ 12 is the bile duct and the second organ 14 is the duodenum. When the purpose is drainage, the bile duct, which is the first organ 12, has a narrowed portion 12b that obstructs the drainage of bodily fluids such as bile. By placing a tube stent 10 at the location of this narrowed portion 12b of the first organ 12, it becomes possible to promote the drainage of bodily fluids through the tube stent 10.

[0012] In this configuration, the tube stent 10 is used as an inside stent, positioned entirely behind the inlet 12a of the first organ 12. In this case, when the tube stent 10 is placed inside the first organ 12, the first filamentous member 16 connected to the tube stent 10 is also placed inside the body. A portion of this first filamentous member 16 is pulled out from the inlet 12a of the first organ 12 and placed in the second organ 14. By pulling the portion of the first filamentous member 16 inside the second organ 14, the tube stent 10 inside the first organ 12 can be removed.

[0013] Refer to Figure 2. The delivery system 20 using the tube stent 10 will be described. The delivery system is used to deliver the tube stent 10 to the first organ 12 (in this embodiment, the stenotic portion 12b of the first organ 12) that is to be treated.

[0014] The delivery system 20 includes, in addition to the aforementioned tube stent 10, an inner catheter 22, an outer catheter 24 through which the inner catheter 22 passes, and a connector 28 that releasably connects the inner catheter 22 and the outer catheter 24. The tube stent 10 is positioned at the tip of the outer catheter 24, and the inner catheter 22 passes through it.

[0015] Hereinafter, the direction along the centerline of the inner catheter 22 will be referred to as the axial direction, and the radial and circumferential directions relative to that centerline will simply be referred to as the radial and circumferential directions. The delivery system 20 has its tip end (left side in the figure), which is one end in the axial direction, inserted into the body, and its proximal end (right side in the figure), which is the other end in the axial direction, positioned outside the body. In Figure 2, for convenience, the tube stent 10 and inner catheter 22 are shown in a straight line. When no external force is applied, they may be curved or bent in some parts.

[0016] Each of the tube stent 10, the inner catheter 22, and the outer catheter 24 is a tubular member and has flexibility that allows for bending deformation. A guide wire lumen (not shown) is formed inside the inner catheter 22. The connector 28 includes a first connector portion 28a attached to the proximal end portion of the inner catheter 22 and a second connector portion 28b attached to the proximal end portion of the outer catheter 24 and releasably connected to the first connector portion 28a.

[0017] Refer to FIG. 3. The delivery system 20 includes a first filamentous member 16 non - releasably connected to the tube stent 10 and a second filamentous member 30 releasably connecting the tube stent 10 and the outer catheter 24. The first filamentous member 16 is not for connecting the tube stent 10 and the outer catheter 24 like the second filamentous member 30. The second filamentous member 30 serves to prevent the axial separation between the outer catheter 24 and the tube stent 10. The delivery system 20 of the present embodiment is characterized by the first and second filamentous members 16, 30 and the peripheral structures related thereto. Further description will be given below regarding these.

[0018] Refer to FIGS. 4 and 5. In FIGS. 4 and 5, the second filamentous member 30 is omitted. A lumen 24a through which the inner catheter 22 passes is formed inside the outer catheter 24. A lumen 10a through which the inner catheter 22 passes is formed inside the tube stent 10.

[0019] A first side hole 24b is formed at the distal end of the outer catheter 24. The first side hole 24b radially penetrates a location that separates the lumen 24a in the outer catheter 24 from the external space. A second side hole 24c is formed in the outer catheter 24 on the proximal side of the first side hole 24b. The second side hole 24c radially penetrates a location that separates the first lumen 24a in the outer catheter 24 from the external space. The first side hole 24b is provided on the distal side of a marker portion 24d provided on the outer catheter 24. This marker portion 24d is composed of a material having radiation impermeability to radiation such as X-rays. This material is, for example, barium, gold, platinum, or the like. The marker portion 24d is used to specify the position of the distal end of the outer catheter 24 in a captured image using radiation. The marker portion 24d of the present embodiment is provided by a ring member separate from the outer catheter 24. In addition to this, the marker portion 24d may be provided integrally with the outer catheter 24 as a part of the outer catheter 24 by kneading a material having radiation impermeability into a part of the outer catheter 24. The marker portion 24d of the present embodiment is provided on the inner peripheral portion of the outer catheter 24 that forms the first lumen 24a, but may also be provided on the outer peripheral portion thereof.

[0020] As mentioned above, the first filamentous member 16 is irrevocably connected to the tube stent 10. Here, "irrevocably connected" means that when the first filamentous member 16 is connected to the tube stent 10, the structure does not allow for the connection to be released. The second filamentous member 30, as described later, is structured so that the connection between the tube stent 10 and the outer catheter 24 by the second filamentous member 30 can be released by pulling the inner catheter 22. Regarding the first filamentous member 16, "irrevocably connected" can also be said to mean that, unlike the second filamentous member 30, the connection of the first filamentous member 16 to the tube stent 10 cannot be released by operating other members. This "irrevocably connected" does not mean that the first filamentous member 16 is hooked onto other members, and that the hook can be released by pulling the other members toward the proximal end, thereby releasing the connection to the tube stent 10. The phrase "irremovably connected" refers solely to whether or not the connection of the first filamentous member 16 can be released. Therefore, even if the connection of the first filamentous member 16 to the tube stent 10 can be released by severing the first filamentous member 16, this is not considered when determining whether the condition of "irremovably connected" is met. The first filamentous member 16 is not irremovably connected to the outer catheter 24. As a result, when the tube stent 10 is placed in the body, the outer catheter 24 can be separated from the tube stent 10 without being restrained by the first filamentous member 16. It can also be said that the first filamentous member 16 is provided in such a way as not to prevent the separation of the outer catheter 24 from the tube stent 10 when separating them.

[0021] The first filamentous member 16 has a folded portion 32 connected to the tube stent 10 and a pair of filamentous portions 34 connected to the folded portion 32. When it is stated in this specification that a particular part (in this case, the folded portion 32, etc.) "has", it also means that the object being referred to (in this case, the first filamentous member 16) forms that particular part (in this case, the folded portion 32, etc.).

[0022] In this embodiment, the folded portion 32 is formed between a pair of thread holes 10b formed in the tube stent 10 by passing the first thread-like member 16 through the pair of thread holes 10b formed in the tube stent 10, and is connected to the tube stent 10 by hooking it onto the tube stent 10. In Figure 4, the thread holes 10b are shown as black circles, and a part of the first thread-like member 16 on the outside of the tube stent 10 is shown as a dashed line. In this embodiment, the folded portion 32 is formed between a pair of thread holes 10b and on the outside of the tube stent 10, and is hooked onto the outer circumference of the tube stent 10. Alternatively, the folded portion 32 may be formed between a pair of thread holes 10b and on the inside of the tube stent 10, and may be hooked onto the inner circumference or thread holes 10b of the tube stent 10. In addition, the folded portion 32 may be formed by passing the first filamentous member 16 through a single filament hole 10b, and then connecting it to the tube stent 10 by hooking it onto the filament hole 10b. This single filament hole 10b may be the third side hole 10d of the tube stent 10, which will be described later, or it may be formed separately from the third side hole 10d. In any case, the folded portion 32 in this embodiment is formed by passing it through the filament hole 10b of the tube stent 10 and is connected to the tube stent 10 by hooking it onto it.

[0023] When the folded portion 32 is connected to the tube stent 10 by hooking, if the pair of thread-like portions 34 can move freely relative to each other, pulling either thread-like portion 34 toward the base end will release the connection of the first thread-like member 16 to the tube stent 10. To avoid this, the first thread-like member 16 is provided with a connecting portion 36A (described later) that connects the pair of thread-like portions 34. This prevents the connection of the first thread-like member 16 from being released due to the free relative movement of the pair of thread-like portions 34, and makes it impossible to release the connection of the first thread-like member 16.

[0024] The first filamentous member 16 is passed between the inner catheter 22 and the outer catheter 24, at least a portion of it, on the proximal end side of the first side hole 24b. In this embodiment, this condition is satisfied only by a portion of the first filamentous member 16 on the proximal end side of the first side hole 24b, but it may be the entirety of it. Furthermore, in this embodiment, this condition is satisfied in each of the pair of filamentous portions 34.

[0025] The first filamentous member 16 is passed through the first side hole 24b. Consider the axial range R from the tip of the outer catheter 24 to the first side hole 24b. In this case, the first filamentous member 16 is positioned outside the outer catheter 24 in at least a portion of its axial range R. The first filamentous member 16 is not positioned inside the outer catheter 24 throughout its entire axial range R. In this embodiment, the portion that satisfies this condition is the entirety of the first filamentous member 16 within its axial range R, but it may also be a portion thereof. In this embodiment, this condition is satisfied in each of the pair of filamentous portions 34.

[0026] The first filamentous member 16 has a first through portion 38 that passes through the first side hole 24b, a first inner portion 40 that is continuous with the first through portion 38, and a first outer portion 42 that is continuous with the first through portion 38. In this embodiment, each of the pair of filamentous portions 34 forms the first through portion 38, the first inner portion 40, and the first outer portion 42, respectively.

[0027] The first inner portion 40 is passed between the inner catheter 22 and the outer catheter 24 at a proximal end to the first side hole 24b. The statement that the first inner portion 40 is "continuous with the first through portion 38" means that there is no outer portion positioned outside the outer catheter 24 between the first inner portion 40 and the first through portion 38.

[0028] The first outer portion 42 is positioned on the outside of the outer catheter 24, towards the tip of the first side hole 24b. The statement that the first outer portion 42 is "continuous with the first through portion 38" means that there is no inner portion positioned inside the outer catheter 24 between the first outer portion 42 and the first through portion 38. In this embodiment, the first outer portion 42 is provided throughout the entire axial range R described above, but it may also be provided only in a portion of the axial range R. This is based on the assumption, for example, that other side holes are formed in the outer catheter 24 towards the tip of the first side hole 24b, and the portion of the first filamentous member 16 that is continuous with the first outer portion 42 passes through these other side holes.

[0029] A portion of each of the pair of thread-like portions 34 in this embodiment is positioned inside the tube stent 10. To achieve this, each of the pair of thread-like portions 34 in this embodiment has a second outer portion 44 that forms a folded portion 32 and is located outside the tube stent 10, a second through portion 46 that is continuous with the second outer portion 44 and passes through the thread hole 10b, and a second inner portion 48 that is continuous with the second through portion 46 and is located inside the tube stent 10. The second inner portion 48 in this embodiment is formed at the proximal end of the tube stent 10 and is drawn out toward the proximal end from an opening 10c that leads to the lumen 10a.

[0030] In this embodiment, the first filamentous member 16 has an intermediate portion 50 that connects a portion of the outer catheter 24 in a certain axial range with a portion of the tube stent 10 in a certain axial range. The intermediate portion 50 in this embodiment is formed by each of the pair of filamentous portions 34. The intermediate portion 50 in this embodiment connects the first outer portion 42 and the second inner portion 48 of the first filamentous member 16. The intermediate portion 50 in this embodiment is positioned to pass between the tube stent 10 and the outer catheter 24.

[0031] The connecting portion 36A in this embodiment connects the intermediate portions of the length range from the folded portion 32 to the end of each of the pair of thread-like portions 34. The connecting portion 36A in this embodiment is composed of a knot connecting the pair of thread-like portions 34, but the specific example is not particularly limited. In addition, the connecting portion 36A may be composed of, for example, a bonding point between the pair of thread-like portions 34 using an adhesive. The connecting portion 36A in this embodiment includes a first connecting portion 36A provided on the tip side portion of the first thread-like member 16.

[0032] The first filamentous member 16 has a pull-out portion 52 that is drawn out from the second side hole 24c to the outside of the outer catheter 24. This allows the operator to grasp a part of the first filamentous member 16 (the pull-out portion 52) from the outside of the outer catheter 24, on the proximal end side of the first side hole 24b, using their fingers, forceps, etc. The pull-out portion 52 has a portion that is inside the second side hole 24c of the outer catheter 24 and a portion that is outside the outer catheter 24 beyond the second side hole 24c. In this embodiment, the pull-out portion 52 is formed by each of the pair of filamentous portions 34. In this embodiment, the pull-out portion 52 constitutes the proximal end of the first filamentous member 16.

[0033] Refer to Figure 6. A third side hole 10d is formed in the proximal end portion of the tube stent 10. The third side hole 10d penetrates radially through the portion of the tube stent 10 that separates the lumen 10a from the external space.

[0034] The second filamentous member 30 in this embodiment is provided with a connecting portion 30a that connects both ends thereof. The connecting portion 30a consists of a knot connecting both ends of the second filamentous member 30, as well as a bonding point using adhesive, etc.

[0035] In this embodiment, the second filamentous member 30 has a first loop portion 30b that is wrapped around the inner catheter 22 and a second loop portion 30c that is hooked onto the outer catheter 24. The pair of portions forming the first loop portion 30b of the second filamentous member 30 are passed through the third side hole 10d of the tube stent 10. The second loop portion 30c is passed through the first side hole 24b of the outer catheter 24 such that a part of the outer catheter 24 is inside the second loop portion 30c. The second loop portion 30c of the second filamentous member 30 is provided so as to pass through the outside of the outer catheter 24, the first side hole 24b, and the inside of the outer catheter 24 in the axial range R. In this way, the outer catheter 24 and the tube stent 10 are connected by the second filamentous member 30.

[0036] Let's consider the case where the outer catheter 24 and the tube stent 10 attempt to separate axially. In this case, the second filamentous member 30 catches on the tip portion of the first side hole 24b of the outer catheter 24. Furthermore, the wrapping of the second filamentous member 30 around the inner catheter 22 prevents the second filamentous member 30 from coming out of the third side hole 10d of the tube stent 10. With the second filamentous member 30 thus prevented from coming out of the third side hole 10d, the proximal portion of the third side hole 10d catches on it. As a result, axial separation of the outer catheter 24 and the tube stent 10 is prevented.

[0037] Refer to Figure 7. In this embodiment, the connection between the outer catheter 24 and the tube stent 10 by the second filamentous member 30 can be released by pulling the inner catheter 22 towards the proximal end relative to the tube stent 10. This pulling operation is performed by pulling the inner catheter 22 towards the proximal end together with the first connector portion 28a of the connector 28. This pulling operation releases the wrapping of the second filamentous member 30 around the inner catheter 22, and the connection between the outer catheter 24 and the tube stent 10 by the second filamentous member 30 is released. At this time, by moving the outer catheter 24 towards the proximal end together with the second filamentous member 30, the second filamentous member 30 comes out of the third side hole 10d of the tube stent 10, allowing the outer catheter 24 and the tube stent 10 to separate in the axial direction.

[0038] The tube stent 10 may be made of various materials, including various resin-based materials such as PTFE. The inner catheter 22 may be made of various materials used in catheters, including various resin-based materials such as olefin resins. The outer catheter 24 may be made of various materials, including various resin-based materials such as PTFE. The first and second filamentous members 16 and 30 are made of thread material, for example, resin fiber, carbon fiber, metal fiber, etc. The first and second filamentous members 16 and 30 may be made of a single thread material, or they may be made by twisting together multiple thread materials.

[0039] The following describes an example of using the delivery system 20. First, prior to using the delivery system 20, a guidewire is inserted in advance through the second organ 14 to the first organ 12 that is to be treated. Next, this guidewire is passed through the guidewire lumen of the inner catheter 22. The delivery system 20 is advanced along the guidewire, through the second organ 14, until the tube stent 10 reaches the target position in the first organ 12. At this time, the delivery system 20 is advanced so as to pass through the lumen of the endoscope.

[0040] After positioning the tube stent 10 at the target location in the first organ 12, the connection between the inner catheter 22 and the outer catheter 24 by the connector 28 is released, and the inner catheter 22 is withdrawn from the tube stent 10 and the outer catheter 24. This releases the connection between the tube stent 10 and the outer catheter 24 by the second filamentous member 30. After this, the outer catheter 24 is withdrawn, and the tube stent 10 is left in the body together with the first filamentous member 16. At this time, as described above, a portion of the first filamentous member 16 is left in the second organ 14.

[0041] The effects of the above delivery system 20 will now be explained. The first filamentous member 16 is positioned outside the outer catheter 24 in at least a portion of the axial range R from the tip of the outer catheter 24 to the first side hole 24b. Therefore, compared to the case where the first filamentous member 16 is positioned between the outer catheter 24 and the inner catheter 22 over the entire axial range R, the number of contact points of the first filamentous member 16 with the inner catheter 22 can be reduced, which is advantageous in reducing the withdrawal resistance of the inner catheter 22.

[0042] The first filamentous member 16 forms a first outer portion 42 that is positioned outside the outer catheter 24 on the tip side of the first side hole 24b. Consider the case in which the first filamentous member 16 is positioned between the outer catheter 24 and the inner catheter 22 over the entire axial range R described above. In this embodiment, compared to this case, the number of contact points of the first filamentous member 16 with the inner catheter 22 can be reduced, which is advantageous in reducing the withdrawal resistance of the inner catheter 22.

[0043] Each of the pair of filamentous portions 34 forms a first outer portion 42 that is positioned outside the outer catheter 24 on the tip side of the first side hole 24b. Consider the case in which the pair of filamentous portions 34 are positioned between the outer catheter 24 and the inner catheter 22 over the entire axial range R described above. In this embodiment, compared to this case, the number of contact points of each of the pair of filamentous portions 34 with the inner catheter 22 can be reduced, which is advantageous in reducing the withdrawal resistance of the inner catheter 22.

[0044] If slack occurs in the first filamentous member 16, the first outer portion 42 of the first filamentous member 16 is more likely to interfere with external objects (for example, an endoscope). In this embodiment, however, the pull-out portion 52 of the first filamentous member 16 is pulled out to the outside of the outer catheter 24. Therefore, when the delivery system 20 is outside the body, the slack in the first outer portion 42 of the first filamentous member 16 can be eliminated by grasping the pull-out portion 52 of the first filamentous member 16 with the operator's fingers, forceps, etc., and pulling it toward the proximal end, thereby suppressing interference with external objects caused by that slack.

[0045] Next, other features of the delivery system 20 will be described. Refer to Figure 4. The outer catheter 24 is provided with a housing hole 60 capable of accommodating the first connector 36A. In this embodiment, the housing hole 60 is formed by the first side hole 24b of the outer catheter 24. Alternatively, the housing hole 60 may be formed by another side hole (not shown) formed in the outer catheter 24 on the tip side of the first side hole 24b. In either case, the housing hole 60 penetrates radially through the portion of the outer catheter 24 that separates the first lumen 24a from the external space. To satisfy the condition of "accommodating" here, the first connector 36A does not need to always be located within the housing hole 60. For example, when slack occurs in the first filamentous member 16, the first connector 36A may come out of the housing hole 60 to the outside of the outer catheter 24. The first connecting portion 36A may be housed in the housing hole 60 when tension is applied to the entire first filamentous member 16, for example, by pulling the base end of the first filamentous member 16 toward the base end. When the delivery system 20 is sent to pass through the lumen of the endoscope, housing the first connecting portion 36A in the housing hole 60 can suppress the increase in frictional resistance due to contact between the lumen forming surface of the endoscope and the first connecting portion 36A.

[0046] The first connecting portion 36A is provided in a portion continuous with the outer portion that is located on the outside of the outer catheter 24 when it is housed in the housing hole 60. In this embodiment, the "outer portion" is exemplified by the first outer portion 42 described above, but it may also be another outer portion located further towards the tip. In this embodiment, the "continuous portion" is exemplified by the first through portion 38 described above, but it may also be a portion that passes through the housing hole 60 formed further towards the tip than the first side hole 24b. Between this portion continuous with the outer portion and the outer portion, there is no inner portion located on the inside of the outer catheter 24. The advantages of this will be explained.

[0047] Let's consider the case where the portion of the first filamentous member 16 that is continuous on both sides in the longitudinal direction with respect to the portion including the first joint 36A is the inner portion that is positioned between the outer catheter 24 and the inner catheter 22. In this case, a part of the first filamentous member 16 comes into contact with the inner surface of the outer catheter 24 at the portion that is continuous on both sides in the longitudinal direction with respect to the first joint 36A (the inner portion), which makes it easier to restrict the radially outward movement of the first joint 36A. As a result, when the inner catheter 22 is withdrawn, the state in which the first joint 36A is in contact with the inner catheter 22 is easily maintained, and there is a problem that the withdrawal resistance of the inner catheter 22 tends to increase due to the first joint 36A.

[0048] In this respect, according to this embodiment, the first connecting portion 36A of the first filamentous member 16 is provided in a portion continuous with the outer portion that is positioned outside the outer catheter 24 when it is housed in the housing hole 60. Therefore, in the portion of the first filamentous member 16 that is continuous with the outer portion side of the portion where the first connecting portion 36A is provided, a part of the first filamentous member 16 does not come into contact with the inner surface of the outer catheter 24, and the first connecting portion 36A can easily move radially outward. As a result, when the inner catheter 22 is withdrawn, it becomes difficult to maintain contact between the first connecting portion 36A and the inner catheter 22, and an increase in the withdrawal resistance of the inner catheter 22 caused by the first connecting portion 36A can be avoided.

[0049] The above-described accommodation hole 60 is set to a size that allows at least the first connecting portion 36A of the first filamentous member 16 to pass through. The accommodation hole 60 in this embodiment is an elongated hole that is long in the axial direction. This allows the first connecting portion 36A to be stably accommodated within the accommodation hole 60 even if the outer catheter 24 is displaced in the axial direction relative to the tube stent 10. The accommodation hole 60 in this embodiment extends linearly along the axial direction. In addition, the accommodation hole 60 may extend diagonally in the circumferential direction toward the axial direction. The minimum width in the width direction perpendicular to the length direction of the accommodation hole 60 is denoted as W. At this time, the length in the length direction of the accommodation hole 60 as an elongated hole is not particularly limited, but for example it may be twice or more the minimum width W.

[0050] The diameter of the first filamentous member 16 may be larger than the diameter of the second filamentous member 30. Here, diameter refers to the maximum diameter (m) of the cross section perpendicular to the longitudinal direction of the first filamentous member 16. If the first filamentous member 16 has a connecting portion 36A, it refers to the diameter at the point where the connecting portion 36A is not present. In order to satisfy these conditions, the diameter of the first filamentous member 16 may be twice or more the diameter of the second filamentous member 30. This ensures the strength of the first filamentous member 16 compared to the case where the diameter of the first filamentous member 16 is the same as the diameter of the second filamentous member 30. Therefore, it is advantageous in preventing breakage when the first filamentous member 16 is pulled in order to remove the tube stent 10 implanted in the body. In addition, compared to the case where the diameter of the second filamentous member 30 is the same as the diameter of the first filamentous member 16, the second filamentous member 30 can be made less likely to interfere with other components.

[0051] (Second Embodiment) Next, the delivery system 20 of the second embodiment will be described. In the following embodiments, the same content as in the first embodiment may apply to the components described in the first embodiment that are not described below.

[0052] Refer to Figure 8. The delivery system 20 in this embodiment differs from the first embodiment in the second connecting portion 36B, which will be described later. The connecting portions 36A and 36B in this embodiment include the first connecting portion 36A and the second connecting portion 36B provided on the base end side of the first filamentous member 16. The second connecting portion 36B is provided on the pull-out portion 52 of the first filamentous member 16. The size of the second connecting portion 36B is usually larger than the size of the portion adjacent to the second connecting portion 36B in the longitudinal direction of the first filamentous member 16. The size here refers to the maximum outer diameter in the direction perpendicular to the direction along the straight line when the portions adjacent to the second connecting portion 36B in the longitudinal direction of the first filamentous member 16 are lined up in a straight line. By providing such a second connecting portion 36B on the pull-out portion 52, it is possible to easily grasp the first filamentous member 16 at the location of the second connecting portion 36B with the operator's fingers, forceps, etc. Such effects can be obtained, for example, when the delivery system 20 is outside the body and the pull-out portion 52 of the first filamentous member 16 is grasped to eliminate slack in the first outer portion 42. In addition, these effects can be obtained when the second connecting portion 36B of the first filamentous member 16 is grasped to remove the tube stent 10 that has been placed in the first organ 12. The size of this second connecting portion 36B is set to be large enough to pass through the first side hole 24b and the second side hole 24c of the outer catheter 24. This prevents the second connecting portion 36B from getting caught in either of the side holes 24b or 24c when separating the outer catheter 24 from the tube stent 10, thus preventing the separation of the two.

[0053] In this embodiment, the second connecting portion 36B can be positioned within the second side hole 24c of the outer catheter 24. This makes it possible to suppress the increase in frictional resistance caused by contact between the lumen-forming surface of the endoscope and the second connecting portion 36B when the delivery system 20 is delivered through the lumen of the endoscope.

[0054] Next, we will describe the transformation forms of each component described so far.

[0055] The specific manner in which the first filamentous member 16 is irremovably connected to the tube stent 10 is not particularly limited. For example, the end portion of the first filamentous member 16 may be attached to a part of the tube stent 10 by a knot or the like to make the connection irremovable.

[0056] Only one of the pair of filamentous portions 34 may form the first outer portion 42 of the first filamentous member 16, while the other filamentous portion 34 is positioned inside the outer catheter 24 within the aforementioned axial range R. Alternatively, only one of the pair of filamentous portions 34 may be positioned inside the tube stent 10, while the other filamentous portion 34 is not positioned inside the tube stent 10.

[0057] The first filamentous member 16 does not necessarily have to include one or both of the first and second connecting portions 36A and 36B. For example, the first filamentous member 16 may have only the second connecting portion 36B.

[0058] The receiving hole 60 does not have to be an elongated hole. Furthermore, the shape of the receiving hole 60 is not particularly limited and may be various shapes such as a circular hole, a semicircular hole, or a rectangular hole. In addition, the receiving hole 60 may be provided at the tip of the outer catheter 24. In this case, the receiving hole 60 may open axially toward the tube stent 10 side.

[0059] The delivery system 20 does not necessarily have to include the second filamentous member 30. The relative sizes of the diameters of the first filamentous member 16 and the second filamentous member 30 are not particularly limited and may be the same. The specific structure for releasably connecting the tube stent 10 and the outer catheter 24 with the second filamentous member 30 is not particularly limited and various structures, including known structures, may be adopted. In the first embodiment, the inner catheter 22 can also be said to have constituted a release member that could release the connection between the outer catheter 24 and the tube stent 10 by the second filamentous member 30 by a pulling operation. This release member may be provided separately from the inner catheter 22.

[0060] The contents of each component described in the embodiments above are illustrative. The abstract technical ideas derived from these should not be interpreted restrictively to the contents of this specification. Many design changes, such as modifications, additions, and deletions, are possible for each component described in the embodiments. Such design changes are emphasized with the notations "this form" and "embodiment." However, design changes are also permitted for content without such notations. Any combination of the above components is also valid. The hatching applied to the cross-sections in the drawings does not limit the material to which the hatching is applied. [Explanation of Symbols]

[0061] 10...Tube stent, 16...First thread-like member, 20...Delivery system, 22...Inner catheter, 24...Outer catheter, 24b...First side hole, 24c...Second side hole, 30...Second thread-like member, 34...Thread-like part, 36A...First connection part, 36B...Second connection part, 38...First through part, 40...First inner part, 42...First outer part, 48...Second inner part, 52...Outlet part.

Claims

1. Inner catheter and An outer catheter through which the inner catheter is passed and a first side hole is formed, A tube stent is positioned at the tip of the outer catheter and through which the inner catheter passes; The first filamentous member is irremovably connected to the tube stent, and at least a portion of the first filamentous member on the proximal end side of the first side hole is passed between the inner catheter and the outer catheter, The first filamentous member is passed through the first side hole and is positioned outside the outer catheter in at least a portion of the axial range from the tip of the outer catheter to the first side hole as part of the delivery system.

2. The first filamentous member is The first through portion that passes through the first side hole, A first inner portion that is continuous with the first through portion and passes between the inner catheter and the outer catheter at the proximal end of the first side hole, The delivery system according to claim 1, further comprising: a first outer portion continuous with the first through portion and positioned outside the outer catheter at a tip-side to the first side hole.

3. The first thread-like member has a folded portion connected to the tube stent and a pair of thread-like portions connected to the folded portion. The delivery system according to claim 2, wherein each of the pair of filamentous portions forms the first outer portion.

4. The delivery system according to claim 3, wherein a portion of each of the pair of filamentous parts is arranged inside the tube stent.

5. The first thread-like member has a folded portion connected to the tube stent and a pair of thread-like portions connected to the folded portion. The delivery system according to claim 2, wherein the first filamentous member comprises a connecting portion for connecting the pair of filamentous portions.

6. The outer catheter is composed of the first side hole or other side holes formed in the outer catheter at a tip-side to the first side hole, and is equipped with a receiving hole capable of accommodating the connecting portion. The delivery system according to claim 5, wherein the connecting portion is provided in a portion of the first filamentous member that is continuous with the outer portion that is positioned outside the outer catheter when it is housed in the housing hole.

7. The delivery system according to claim 6, wherein the receiving hole is an elongated hole that is long in the axial direction.

8. The outer catheter has a second side hole formed on the proximal side of the first side hole. The delivery system according to claim 2, wherein the first filamentous member has a pull-out portion that is pulled out from the second side hole to the outside of the outer catheter.

9. The first thread-like member has a folded portion connected to the tube stent and a pair of thread-like portions connected to the folded portion. The first filamentous member is provided with a connecting portion that connects the pair of filamentous portions, The delivery system according to claim 8, wherein the coupling portion is provided in the drawer portion.

10. The delivery system according to claim 2, further comprising a second filamentous member that releasably connects the tube stent and the outer catheter.

11. The delivery system according to claim 10, wherein the diameter of the first filamentous member is greater than the diameter of the second filamentous member.

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