Delivery system

Abstract

The present invention comprises: an inner catheter 22; an outer catheter 24 through which the inner catheter 22 is passed and in which a first side hole 24b is formed; a tube stent 10 which is disposed distally relative to the outer catheter 24 and through which the inner catheter 22 is passed; and a first thread-like member 16 which is non-releasably coupled to the tube stent 10 and at least a part of which is passed between the inner catheter 22 and the outer catheter 24 at a position more proximal than the first side hole 24b. The first thread-like member 16 is passed through the first side hole 24b and is disposed on the outer side of the outer catheter 24 in at least a part of an axial range R from the distal end of the outer catheter 24 to the first side hole 24b.

Description

Delivery System

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

[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 side with respect to the outer catheter through which the inner catheter is passed. The delivery system of Patent Document 1 includes a first filament member connected to the tube stent. This first filament member is passed between the inner catheter and the outer catheter on both axial sides with respect to the first side hole.

[0003] Japanese Patent Application Laid-Open No. 2012-239803

[0004] When the inner catheter is withdrawn proximally with respect to the outer catheter, a withdrawal resistance is generated in the inner catheter due to friction with the first filament member. The inventor of the present application has recognized that there is room for improvement in reducing the withdrawal 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 that is advantageous for reducing the withdrawal resistance of the inner catheter.

[0006] The delivery system of the present disclosure includes an inner catheter, an outer catheter through which the inner catheter is passed and a first side hole is formed, a tube stent disposed on the distal side with respect to the outer catheter through which the inner catheter is passed, and a first filament member irreversibly connected to the tube stent, wherein at least a part of the first filament member is passed between the inner catheter and the outer catheter on the proximal side of the first side hole, and the first filament member is passed through the first side hole and is disposed outside the outer catheter at least in a part of the axial range from the distal end of the outer catheter to the first side hole.

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

[0008] This is an explanatory diagram illustrating an example of the use of a tube stent. This is a side view of the delivery system of the first embodiment. This is a schematic diagram showing an enlarged portion of Figure 2. This is a schematic side cross-sectional view illustrating the first filamentous member of the first embodiment together with the surrounding structure. This is a view of a part of the delivery system from the direction of arrow V in Figure 4. This is a schematic side cross-sectional view illustrating the second filamentous member of the first embodiment together with the surrounding structure. This is an explanatory diagram illustrating the operation when the connection by the second filamentous member is released. This is a schematic side cross-sectional view illustrating the first filamentous member of the second embodiment together with the surrounding structure. This is a schematic side cross-sectional view of the first filamentous member of the third embodiment, viewed from the same viewpoint as in Figure 4.

[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 scenario 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, etc., 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, the drainage of bodily fluids can be promoted through the tube stent 10.

[0012] In this embodiment, 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. A delivery system 20 using a tube stent 10 will be described. The delivery system is used to deliver the tube stent 10 to the first organ 12 to be treated (in this embodiment, the stenotic portion 12b of the first organ 12).

[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] The tube stent 10, inner catheter 22, and outer catheter 24 are each tubular members and are flexible and can be bent. A guidewire lumen (not shown) is formed inside the inner catheter 22. The connector 28 includes a first connector portion 28a attached to the proximal end of the inner catheter 22 and a second connector portion 28b attached to the proximal end of the outer catheter 24, to which the first connector portion 28a is releasably connected.

[0017] Refer to Figure 3. The delivery system 20 comprises a first filamentous member 16 that is irremovably connected to the tubular stent 10, and a second filamentous member 30 that removably connects the tubular stent 10 and the outer catheter 24. The first filamentous member 16 is not for connecting the tubular stent 10 and the outer catheter 24, like the second filamentous member 30. The second filamentous member 30 serves to prevent axial separation of the outer catheter 24 and the tubular stent 10. The delivery system 20 in this embodiment is characterized by the first and second filamentous members 16 and 30 and the surrounding structures related thereto. These will be described further below.

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

[0019] A first side hole 24b is formed at the tip of the outer catheter 24. The first side hole 24b penetrates radially through the portion of the outer catheter 24 that separates the lumen 24a 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 penetrates radially through the portion of the outer catheter 24 that separates the first lumen 24a from the external space. The first side hole 24b is located on the tip side of the outer catheter 24, beyond the marker portion 24d provided on the outer catheter 24. This marker portion 24d is made of a material that is opaque to radiation such as X-rays. This material can be, for example, barium, gold, or platinum. The marker portion 24d is used to identify the position of the tip of the outer catheter 24 in imaging images using radiation. In this embodiment, the marker portion 24d is provided by a ring member separate from the outer catheter 24. In addition, the marker portion 24d may be integrally provided with the outer catheter 24 by mixing a material that is radiopaque to radiation into a part of the outer catheter 24. In this embodiment, the marker portion 24d is provided on the inner circumference of the outer catheter 24 that forms the first lumen 24a, but it may also be provided on the outer circumference.

[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 another member. This "irrevocably connected" does not mean that the first filamentous member 16 is hooked onto another member, and that the hook can be released by pulling the other member towards 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 or not 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 thread-like member 16 through a single thread hole 10b, and then connecting it to the tube stent 10 by hooking it onto the thread hole 10b. This single thread 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 thread 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 which is 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 entire portion. 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 in 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 over the entire axial range R described above, but as will be described later with reference to Figure 9, it may also be provided over only a portion of the axial range R.

[0029] In this embodiment, a portion of each pair of thread-like portions 34 is positioned inside the tube stent 10. To achieve this, each 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 base end of the tube stent 10 and is drawn out toward the base 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 formed by 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 formed, for example, by the bonding point of 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 filamentary member 16 forms a first outer portion 42 that is disposed outside the outer catheter 24 on the distal side of the first side hole 24b. Consider the case where the first filamentary member 16 is disposed between the outer catheter 24 and the inner catheter 22 throughout the entire axial range R described above. According to this embodiment, compared with such a case, the contact locations of the first filamentary member 16 with respect to the inner catheter 22 can be reduced, which is advantageous for reducing the withdrawal resistance of the inner catheter 22.

[0043] Each of the pair of filamentary portions 34 forms a first outer portion 42 that is disposed outside the outer catheter 24 on the distal side of the first side hole 24b. Consider the case where the pair of filamentary portions 34 is disposed between the outer catheter 24 and the inner catheter 22 throughout the entire axial range R described above. According to this embodiment, compared with such a case, the contact locations of each of the pair of filamentary portions 34 with respect to the inner catheter 22 can be reduced, which is advantageous for reducing the withdrawal resistance of the inner catheter 22.

[0044] When slack occurs in the first filamentary member 16, the first outer portion 42 of the first filamentary member 16 is likely to interfere with an external object (for example, an endoscope or the like). In this regard, according to this embodiment, the lead-out portion 52 of the first filamentary member 16 is led out to the outside of the outer catheter 24. Therefore, when the delivery system 20 is outside the body, by pulling the lead-out portion 52 of the first filamentary member 16 with the fingers, forceps, etc. of the operator in a pinched state toward the proximal end side, the slack of the first outer portion 42 of the first filamentary member 16 can be eliminated, and interference with the external object due to the slack can be suppressed.

[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 a fourth side hole 24e formed in the outer catheter 24 on the tip side of the first side hole 24b, as will be described later with reference to Figure 9. 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. In order to satisfy the condition of "accommodating" here, the first connector 36A does not need to always be located inside 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 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 that is 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] Consider a case where a portion of the first filamentary member 16 that includes the first coupling portion 36A is an inner portion disposed between the outer catheter 24 and the inner catheter 22, with portions continuous on both sides in the longitudinal direction with respect to the portion including the first coupling portion 36A. In this case, at locations (inner portions) continuous on both sides in the longitudinal direction with respect to the first coupling portion 36A, a part of the first filamentary member 16 contacts the inner surface of the outer catheter 24, making it easier to restrain the radial outward movement of the first coupling portion 36A. As a result, when pulling out the inner catheter 22, the state where the first coupling portion 36A contacts the inner catheter 22 is likely to be maintained, and there is a problem that the pulling resistance of the inner catheter 22 is likely to increase due to the first coupling portion 36A

[0048] In this regard, according to the present embodiment, the first coupling portion 36A of the first filamentary member 16 is provided at a portion continuous with an outer portion disposed outside the outer catheter 24 when being accommodated in the accommodation hole 60. Thus, in the first filamentary member 16, at a location continuous with the outer portion side with respect to the portion where the first coupling portion 36A is provided, a part of the first filamentary member 16 does not contact the inner surface of the outer catheter 24, and the first coupling portion 36A is likely to move radially outward. As a result, when pulling out the inner catheter 22, it becomes difficult to maintain the state where the first coupling portion 36A contacts the inner catheter 22, and an increase in the pulling resistance of the inner catheter 22 due to the first coupling portion 36A can be avoided

[0049] The above-mentioned accommodation hole 60 is set to a size that can at least pass through the first coupling portion 36A of the first filamentary member 16. The accommodation hole 60 of the present embodiment is a long hole that is long in the axial direction. Thereby, even if the outer catheter 24 is axially displaced with respect to the tube stent 10, the first coupling portion 36A can be stably accommodated in the accommodation hole 60. The accommodation hole 60 of the present embodiment extends linearly along the axial direction. In addition to this, the accommodation hole 60 may extend obliquely in the circumferential direction toward the axial direction. Let the minimum width in the width direction orthogonal to the length direction of the accommodation hole 60 be W. At this time, although the length in the length direction of the accommodation hole 60 as a long hole is not particularly limited, 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 location 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. Also, 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 of this embodiment differs from the first embodiment in the second connecting portion 36B, which will be described later. The connecting portions 36A and 36B of this embodiment include the first connecting portion 36A and the second connecting portion 36B provided on the base end portion 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, the first filamentous member 16 can be easily grasped at the location of the second connecting portion 36B by 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 due to contact between the lumen-forming surface of the endoscope and the second connecting portion 36B when the delivery system 20 is sent through the lumen of the endoscope.

[0054] (Third Embodiment) Refer to Figure 9. In this embodiment, the outer catheter 24 has a fourth side hole 24e formed on the tip side of the first side hole 24b, which is a different side hole from the first side hole 24b. The first filamentous member 16 in this embodiment has a third through portion 62 that is continuous with the first outer portion 42 on the tip side of the first outer portion 42 and passes through the fourth side hole 24e. Unlike the first embodiment, the first outer portion 42 of the first filamentous member 16 is provided only in a part of the axial range R from the tip of the outer catheter 24 to the first side hole 24b.

[0055] The housing hole 60 may be configured with a fourth side hole 24e instead of the first side hole 24b of the first embodiment, as in this embodiment. The first connecting portion 36A that connects the pair of filamentous portions 34 of the first filamentous member 16 may be housed in this housing hole 60. In this case, the housing hole 60 may be provided at the tip of the outer catheter 24, as in this embodiment. In this case, the housing hole 60 may open axially toward the tube stent 10, as in this embodiment.

[0056] Next, we will describe the transformation forms of each component described so far.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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 can 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.

[0062] 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.

[0063] This disclosure relates to a delivery system.

[0064] 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 connecting part, 36B...Second connecting part, 38...First through part, 40...First inner part, 42...First outer part, 48...Second inner part, 52...Outlet part.

Claims

1. A delivery system comprising: an inner catheter; an outer catheter through which the inner catheter passes and through which a first side hole is formed; a tubular stent positioned distal to the outer catheter and through which the inner catheter passes; 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.

2. The delivery system according to claim 1, wherein the first filamentous member comprises: a 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 a proximal end to the first side hole; and a first outer portion that is continuous with the first through portion and positioned outside the outer catheter at a distal end to the first side hole.

3. The delivery system according to claim 2, wherein the first filamentous member has a folded portion connected to the tube stent and a pair of filamentous portions connected to the folded portion, and 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 delivery system according to any one of claims 2 to 4, wherein the first filamentous member has a folded portion connected to the tube stent and a pair of filamentous portions connected to the folded portion, and the first filamentous member has a connecting portion that connects the pair of filamentous portions.

6. The delivery system according to claim 5, wherein 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 has a receiving hole capable of accommodating the connecting portion, and 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 accommodated in the receiving 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 delivery system according to any one of claims 2 to 7, wherein the outer catheter has a second side hole formed on the proximal end side of the first side hole, and 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 delivery system according to claim 8, wherein the first filamentous member has a folded portion connected to the tube stent and a pair of filamentous portions connected to the folded portion, the first filamentous member has a connecting portion that connects the pair of filamentous portions, and the connecting portion is provided in the pull-out portion.

10. The delivery system according to any one of claims 2 to 9, 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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