INTRODUCTION SYSTEM

Abstract

[Problem] Provision of an insertion system that is advantageous in reducing the withdrawal resistance of an internal catheter. [Solution] Delivery system, equipped with: 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 tubular stent 10, which is arranged on a distal end side with respect to the outer catheter 24, wherein the inner catheter 22 is passed through the tubular stent 10; and a first thread-like element 16 which is inseparably connected to the tubular stent 10, wherein at least one section of the first thread-like element 16 runs between the inner catheter 22 and the outer catheter 24 on a side which is closer to the proximal end than the first side hole 24b, and wherein the first thread-like element 16 is passed through the first side hole 24b and is arranged outside the outer catheter 24 in at least a part of an axial region R from the distal end of the outer catheter 24 to the first side hole 24b.

Description

TECHNICAL AREA

[0001] The present disclosure relates to a contribution system. STATE OF THE ART

[0002] Patent document 1 discloses a delivery system for inserting a tubular stent. This delivery system comprises an inner catheter, an outer catheter through which the inner catheter passes and in which a first lateral opening is formed, and a tubular stent arranged at a distal end face with respect to the outer catheter, the inner catheter passing through the tubular stent. The delivery system of patent document 1 includes a first thread-like element connected to the tubular stent. The first thread-like element extends between the inner catheter and the outer catheter on both axial sides with respect to the first lateral opening. LITERATURE LIST Patent literature

[0003] Patent Literature 1: JP 2012-239803 A BRIEF DESCRIPTION OF THE INVENTION Technical Problem

[0004] When the inner catheter is withdrawn towards its proximal end relative to the outer catheter, friction with the first thread-like element causes withdrawal resistance. The inventors of the present application have recognized that there is potential for improvement in reducing the withdrawal resistance of the inner catheter in the insertion system described in patent literature 1.

[0005] Accordingly, one objective of the present disclosure is to provide an insertion system that is advantageous for reducing the withdrawal resistance of an internal catheter. Solution to the problem

[0006] An insertion system of the present disclosure is provided with: an inner catheter; an outer catheter through which the inner catheter is passed and in which a first side hole is formed; a tubular stent arranged on the distal end side with respect to the outer catheter, the inner catheter being passed through the tubular stent; and a first thread-like element inseparably connected to the tubular stent, wherein at least a section of the first thread-like element extends between the inner catheter and the outer catheter on a side closer to the proximal end than the first side hole, the first thread-like element being passed through the first side hole and being arranged outside the outer catheter in at least a part of an axial region from the distal end of the outer catheter to the first side hole. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0007] The insertion system according to the present disclosure is advantageous for reducing the withdrawal resistance of an internal catheter. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is an illustrative view of an application example of a tubular stent. Fig. Figure 2 is a side view of an insertion system of a first embodiment. Fig. Figure 3 is an enlarged schematic representation of a section of Fig. 2. Fig. Figure 4 is a side sectional view that schematically illustrates a first thread-like element of the first embodiment together with surrounding structures. Fig. Figure 5 is a view of a section of the insertion system, from the direction of arrow V in Fig. 4 considered. Fig. Figure 6 is a side sectional view that schematically illustrates a second thread-like element of the first embodiment together with surrounding structures. Fig. Figure 7 is an explanatory view that schematically shows a process in which a connection is broken by the second thread-like element. Fig. Figure 8 is a side sectional view that schematically illustrates a first thread-like element of a second embodiment together with surrounding structures. Fig. Figure 9 is a schematic side sectional view showing a first thread-like element of a third embodiment from the same perspective as Fig. 4 illustrates. DESCRIPTION OF EXECUTION FORMS

[0008] The following describes embodiments of the insertion system of the present disclosure. Identical or equivalent elements are designated with the same reference numerals, and duplicate descriptions are avoided. In each drawing, elementary components are omitted, enlarged, or reduced as necessary to simplify the description. The drawings are to be viewed according to the orientation of the reference numerals. In this specification, the notation "nth" (where n is a natural number), like "first" or "second," is used only as a formal description to distinguish between multiple elements and has no other essential meaning. For example, any element designated as "nth" may exist independently and without continuity. That is, a "second" element may exist without a "first" element. First embodiment

[0009] A first embodiment is described with reference to Fig. 1. First, an application scenario of a tubular stent 10 used in the delivery system is described. The tubular stent 10 is used for the purpose of a procedure (hereinafter referred to as treatment) in connection with a medical treatment or examination of a living body. The tubular stent 10 of the present embodiment is used for drainage, such as biliary drainage or pancreatic drainage.

[0010] The living body comprises a first organ 12, which is to be treated, and a second organ 14, into which an access 12a to the first organ 12 opens. An example is described here in which the first organ 12 is a bile duct and the second organ 14 is a duodenum. In a case where the tubular stent 10 is used for drainage purposes, the bile duct or the like, which serves as the first organ 12, has a stricture 12b that prevents the outflow of body fluids such as bile.

[0011] By placing the tubular stent 10 in the first organ 12 at the site of the stricture 12b, the outflow of body fluid through the tubular stent 10 can be promoted.

[0012] The tubular stent 10 of the present embodiment is used as an internal stent, positioned entirely further inside the first organ 12 than the access point 12a. In this case, when the tubular stent 10 is inserted into the first organ 12, a first thread-like element 16, connected to the tubular stent 10, is also inserted into the body. A portion of the first thread-like element 16 is withdrawn from the access point 12a to the first organ 12 and positioned in the second organ 14. The tubular stent 10 in the first organ 12 can be removed by pulling on a portion of the first thread-like element 16 located in the second organ 14.

[0013] The present disclosure is made with reference to Fig. 2 is described in more detail. A delivery system 20 is described in which the tubular stent 10 is used. The delivery system is used to insert the tubular stent 10 into the first organ 12 to be treated (in the present embodiment, the stricture 12b of the first organ 12).

[0014] The delivery system 20 includes, in addition to the tubular stent 10 described above, an inner catheter 22, an outer catheter 24 through which the inner catheter 22 passes, and a connector 28 that detachably connects the inner catheter 22 and the outer catheter 24. The tubular stent 10 is positioned at its distal end relative to the outer catheter 24, and the inner catheter 22 passes through it.

[0015] In the following, a direction along a centerline of the inner catheter 22 is referred to as the axial direction, and a radial direction and a circumferential direction based on the centerline are simply referred to as the radial direction and circumferential direction, respectively. In the delivery system 20, the distal end (the left side in the drawing), which represents one end in the axial direction, is inserted into the body, and the proximal end (the right side in the drawing), which represents the other end in the axial direction, is positioned outside the body. For simplicity, Fig. 2 a state in which the tubular stent 10 and the inner catheter 22 are extended in a straight line. These may be partially curved or bent if no external force is applied.

[0016] The tubular stent 10, the inner catheter 22, and the outer catheter 24 are each tubular elements with a flexibility that allows them to be bent and deformed. A guide wire lumen (not shown) is formed inside the inner catheter 22. The connector 28 includes a first connector part 28a, which is attached to the proximal end section of the inner catheter 22, and a second connector part 28b, which is attached to the proximal end section of the outer catheter 24 and is detachably connected to the first connector part 28a.

[0017] The present disclosure is made with reference to Fig. Figure 3 is described in more detail. The delivery system 20 comprises a first thread-like element 16, which is permanently connected to the tubular stent 10, and a second thread-like element 30, which detachably connects the tubular stent 10 and the external catheter 24. The first thread-like element 16 does not serve to connect the tubular stent 10 to the external catheter 24; this connection is made by the second thread-like element 30. The function of the second thread-like element 30 is to prevent the external catheter 24 and the tubular stent 10 from separating axially. The delivery system 20 of the present embodiment is characterized by the first and second thread-like elements 16 and 30 and the associated surrounding structures. These are described in more detail below.

[0018] The following description refers to Fig. 4 and Fig. 5. In Fig. 4 and Fig. In Figure 5, the second thread-like element 30 is omitted. A lumen 24a is formed within the outer catheter 24, through which the inner catheter 22 runs. A lumen 10a is formed inside the tubular stent 10, through which the inner catheter 22 runs.

[0019] A first side hole 24b is formed at a distal end of the external catheter 24. The first side hole 24b penetrates the external catheter 24 radially at a point that separates the lumen 24a from the external space. A second side hole 24c is formed in the external catheter 24 further towards the proximal end than the first side hole 24b. The second side hole 24c penetrates the external catheter 24 radially at a point that separates the first lumen 24a from the external space. The first side hole 24b is positioned further towards the distal end than a marker section 24d provided in the external catheter 24. The marker section 24d is made of a material that is opaque to radiation, such as X-rays. The material is, for example, barium, gold, platinum, or the like.The marker section 24d is used to accurately indicate the position of the distal end of the outer catheter 24 in a radiographically acquired image. In the present embodiment, the marker section 24d is provided by a ring element separate from the outer catheter 24. Alternatively, the marker section 24d can be integrally formed with the outer catheter 24 by incorporating the radiopaque material into a portion of the outer catheter 24. The marker section 24d in the present embodiment is located on an inner circumferential section of the outer catheter 24 that forms the first lumen 24a, but it can also be located on an outer circumferential section thereof.

[0020] As previously described, the first thread-like element 16 is permanently connected to the tubular stent 10. The term "permanently connected" here means that the first thread-like element 16 is not designed in such a way that it can be detached from its connected state when connected to the tubular stent 10. As described later, the second thread-like element 30 has a structure such that the connection between the tubular stent 10 and the outer catheter 24 can be released by pulling on the inner catheter 22. The expression “inextricably connected” can also be understood in relation to the first thread-like element 16 as meaning that the first thread-like element 16 is not such that the connected state of the first thread-like element 16 with the tubular stent 10 can be released by actuating another element, as is the case with the second thread-like element 30.It can also be said that the expression "permanently connected" does not mean that the first thread-like element 16 is hooked onto another element and that the hooking onto the other element can be released by a pulling action in which the other element is pulled towards its proximal end, thereby breaking the connected state with the tubular stent 10. The expression "permanently connected" is intended to answer the question of whether the first thread-like element 16 is such that the connected state of the first thread-like element 16 can be broken. Even if the connected state of the first thread-like element 16 with the tubular stent 10 can be broken by snapping the first thread-like element 16, such a case is not considered when determining whether the condition "permanently connected" is met.It should be noted that the first thread-like element 16 is not permanently connected to the external catheter 24. Therefore, once the tubular stent 10 is placed in the body, the external catheter 24 can be separated from the tubular stent 10 without being restricted by the first thread-like element 16. In other words, the first thread-like element 16 is designed so that it does not impede the separation of the external catheter 24 from the tubular stent 10 when the external catheter 24 needs to be separated from the tubular stent 10.

[0021] The first thread-like element 16 has a recirculation section 32 connected to the tubular stent 10, as well as a pair of thread-like parts 34 connected to the recirculation section 32. In the present description, the wording "has..." for a specific part (here the recirculation section 32 or the like) can also mean that the mentioned target object (here the first thread-like element 16) forms the specific part (here the recirculation section 32 or the like).

[0022] The return section 32 of the present embodiment is formed between a pair of thread holes 10b by guiding the first thread-like element 16 through the pair of thread holes 10b formed in the tubular stent 10, and the return section 32 is hooked onto the tubular stent 10 and thereby connected to the tubular stent 10. Fig. Figure 4 shows the thread hole 10b marked by a black circle, and the portion of the first thread-like element 16 located outside the tubular stent 10 is indicated by the dashed line. The return section 32 of the present embodiment is formed between the pair of thread holes 10b and outside the tubular stent 10 and is hooked onto the outer circumferential section of the tubular stent 10. Alternatively, the return section 32 can be formed between the pair of thread holes 10b and inside the tubular stent 10 and be hooked onto the inner circumferential section of the tubular stent 10 or onto the thread holes 10b.Furthermore, the first thread-like element 16 can be passed through a single thread hole 10b to form the return section 32 in the portion of the first thread-like element that passes through the thread hole 10b, and the return section 32 can then be hooked onto the thread hole 10b and thereby connected to the tubular stent 10. The single thread hole 10b can be a third side hole 10d of the tubular stent 10 as described below, or it can be formed separately from the third side hole 10d. In either case, the return section 32 of the present embodiment is formed by passing the first thread-like element 16 through the thread hole 10b of the tubular stent 10 and hooking onto the tubular stent 10, thereby connecting it to the stent 10.

[0023] In the case where the return section 32 is connected to the tubular stent 10 by hooking, if the pair of filamentous parts 34 can move freely relative to each other, the connected state of the first filamentous element 16 to the tubular stent 10 could be released by pulling one of the filamentous parts 34 towards its proximal end. To prevent this, the first filamentous element 16 is provided with a coupling element 36A (described later) that couples the pair of filamentous parts 34. By using the coupling element 36A, a situation in which the connected state of the first filamentous element 16 is released due to the unimpeded relative movement of the pair of filamentous parts 34 can be avoided, and the connected state of the first filamentous element 16 can be made irretrievable.

[0024] At least one section of the first thread-like element 16 extends between the inner catheter 22 and the outer catheter 24 on a side closer to the proximal end than the first side hole 24b. In the present embodiment, the section that fulfills this condition is only the section of the first thread-like element 16 on a side closer to the proximal end than the first side hole 24b; however, it could also be the entire first thread-like element 16. Furthermore, in the present embodiment, this condition is fulfilled for each of the pair of thread-like parts 34.

[0025] The first thread-like element 16 passes through the first side hole 24b. An axial region R is considered, extending from the distal end of the outer catheter 24 to the first side hole 24b. The first thread-like element 16 is located outside the outer catheter 24 in at least a portion of the axial region R. Thus, the first thread-like element 16 is not located within the outer catheter 24 over the entire axial region R. In the present embodiment, the portion that fulfills this condition is the entire first thread-like element 16 within the axial region R, although it could also be a portion thereof. In the present embodiment, this condition is fulfilled for each of the pair of thread-like elements 34.

[0026] The first thread-like element 16 has a first through-section 38 that passes through the first side hole 24b, a first inner section 40 that connects continuously to the first through-section 38, and a first outer section 42 that connects continuously to the first through-section 38. In the present embodiment, each of the pair of thread-like parts 34 forms a first through-section 38, a first inner section 40, and a first outer section 42.

[0027] The first inner section 40 runs between the inner catheter 22 and the outer catheter 24 on a side that is closer to the proximal end than the first side hole 24b. The fact that the first inner section 40 "continuously connects to the first passage section 38" means that there is no outer section located outside the outer catheter 24 between the first inner section 40 and the first passage section 38.

[0028] The first outer section 42 is arranged outside the outer catheter 24 on a side closer to the distal end than the first side hole 24b. The fact that the first outer section 42 "continuously connects to the first through-passage section 38" means that there is no inner section located within the outer catheter 24 between the first outer section 42 and the first through-passage section 38. The first outer section 42 of the present embodiment is provided over the entire axial range R described above, but can be, as further described below with reference to Fig. 9 described, may also be provided only in a section of the axial region R.

[0029] A section of each of the pair of thread-like parts 34 in the present embodiment is arranged inside the tubular stent 10. To achieve this, each of the pair of thread-like parts 34 in the present embodiment has a second outer section 44, which forms the return section 32 and is located outside the tubular stent 10, a second through-section 46, which connects continuously to the second outer section 44 and is passed through a thread opening 10b, and a second inner section 48, which connects continuously to the second through-section 46 and is located inside the tubular stent 10. The second inner section 48 of the present embodiment extends from an opening 10c, which is formed in the proximal end section of the tubular stent 10 and is connected to the lumen 10a, towards the proximal end.

[0030] The first thread-like element 16 of the present embodiment has an intermediate section 50 that connects a section of the outer catheter 24 in a specific axial region to a section of the tubular stent 10 in a specific axial region. The intermediate section 50 of the present embodiment is formed by each of the pair of thread-like parts 34. The intermediate section 50 of the present embodiment connects the first outer section 42 and the second inner section 48 of the first thread-like element 16. The intermediate section 50 of the present embodiment is arranged such that it runs between the tubular stent 10 and the outer catheter 24.

[0031] The coupling element 36A of the present embodiment couples the intermediate sections within a length range from the return section 32 to the end of each of the pair of thread-like parts 34. The coupling element 36A of the present embodiment is formed by a knot that connects the pair of thread-like parts 34; however, specific examples of this are not subject to any particular limitations. Furthermore, the coupling element 36A can, for example, be formed by an adhesive joint of the pair of thread-like parts 34 where an adhesive is used. The coupling element 36A of the present embodiment includes a first coupling element 36A, which is provided in the section of the first thread-like element 16 located on the distal end side.

[0032] The first thread-like element 16 has a retractable section 52 that is pulled out of the second side hole 24c toward the outside of the outer catheter 24. Accordingly, a section (the retractable section 52) of the first thread-like element 16 on a side closer to the proximal end than the first side hole 24b can be grasped from the outside of the outer catheter 24 with a surgeon's fingers, forceps, or the like. The retractable section 52 has a portion located within the second side hole 24c of the outer catheter 24 and a portion located further toward the outside of the outer catheter 24 than the second side hole 24c. The retractable section 52 of the present embodiment is formed by each of the pair of thread-like parts 34.The extendable section 52 of the present embodiment forms a proximal end section of the first thread-like element 16.

[0033] The present disclosure is made with reference to Fig. Figure 6 shows in more detail. A third lateral opening 10d is formed in a section of the tubular stent 10 located on the side of the proximal end. The third lateral opening 10d penetrates the tubular stent 10 radially at a point that separates the lumen 10a from the outside space.

[0034] The second thread-like element 30 of the present embodiment includes a coupling part 30a that couples its two end sections. The coupling part 30a is formed by a knot connecting the two end sections of the second thread-like element 30, an adhesive joint, or the like.

[0035] In the present embodiment, the second thread-like element 30 has a first loop section 30b wound around the inner catheter 22 and a second loop section 30c hooked onto the outer catheter 24. The pair of sections forming the first loop section 30b of the second thread-like element 30 passes through the third side hole 10d of the tubular stent 10. The second loop section 30c is threaded through the first side hole 24b of the outer catheter 24, such that a portion of the outer catheter 24 is located within the second loop section 30c. The second loop section 30c of the second thread-like element 30 is positioned to run along the outer surface of the outer catheter 24, through the first side hole 24b, and along the inner surface of the outer catheter 24 in that order in the axial region R.

[0036] Accordingly, the external catheter 24 and the tubular stent 10 are connected by the second thread-like element 30.

[0037] Next, a case is considered in which the outer catheter 24 and the tubular stent 10 attempt to separate axially. In this case, the second thread-like element 30 is hooked onto the distal end portion of the first side hole 24b of the outer catheter 24. Furthermore, the second thread-like element 30 is wound around the inner catheter 22, preventing it from slipping out of the third side hole 10d of the tubular stent 10. In this way, the proximal end portion of the third side hole 10d is hooked onto the second thread-like element 30, preventing it from slipping out of the third side hole 10d. This prevents axial separation of the outer catheter 24 and the tubular stent 10.

[0038] The present disclosure is made with reference to Fig. Figure 7 is shown in more detail. In the present embodiment, the connection formed by the second thread-like element 30 between the outer catheter 24 and the tubular stent 10 can be released by pulling the inner catheter 22 towards the proximal end of the tubular stent 10. This pulling action is performed by pulling the inner catheter 22 together with the first connector part 28a of the connector 28 towards the proximal end. This pulling action releases the winding of the second thread-like element 30 around the inner catheter 22 and releases the connection between the outer catheter 24 and the tubular stent 10 through the second thread-like element 30.In this process, the outer catheter 24 is moved together with the second thread-like element 30 in the direction of the proximal end side, thereby pulling the second thread-like element 30 out of the third side hole 10d of the tube stent 10 and enabling separation of the outer catheter 24 and the tube stent 10 in the axial direction.

[0039] The tubular stent 10 can be made of various materials, including various resin-based materials such as PTFE. The inner catheter 22 can be made of various materials commonly used for catheters, including various resin-based materials such as olefin-based resins. The outer catheter 24 can be made of various materials, including various resin-based materials such as PTFE. The first and second filament-like elements 16 and 30, for example, are made of a filament material that incorporates resin fibers, carbon fibers, metal fibers, or the like. The first and second filament-like elements 16 and 30 can be made of a single filament material or by twisting together a variety of filament materials.

[0040] An application example of the delivery system 20 described above is presented. First, before using the delivery system 20, a guidewire is inserted through the second organ 14 and into the first organ 12 to be treated. The guidewire is then passed through the guidewire lumen of the internal catheter 22. The delivery system 20 is advanced along the guidewire and through the second organ 14 until the tubular stent 10 reaches its target position in the first organ 12. During this process, the delivery system 20 is guided through the lumen of an endoscope.

[0041] After the tubular stent 10 has been positioned at the target location in the first organ 12, the connection between the inner catheter 22 and the outer catheter 24 is released by the connector 28, and the inner catheter 22 is withdrawn from the tubular stent 10 and the outer catheter 24. This releases the connection between the tubular stent 10 and the outer catheter 24, which is formed by the second thread-like element 30. The outer catheter 24 is then withdrawn, thereby placing the tubular stent 10, together with the first thread-like element 16, within the body. As previously described, a portion of the first thread-like element 16 is placed within the second organ 14.

[0042] The action of the insertion system 20 described above is described below. The first thread-like element 16 is arranged outside the outer catheter 24 in at least part of an axial region R from the distal end of the outer catheter 24 to the first side hole 24b. Therefore, compared to a case in which the first thread-like element 16 is arranged in the entire axial region R between the outer catheter 24 and the inner catheter 22, the contact area of ​​the first thread-like element 16 with the inner catheter 22 can be reduced, which is advantageous for reducing the withdrawal resistance of the inner catheter 22.

[0043] The first thread-like element 16 forms a first outer section 42, which is arranged outside the outer catheter 24 on the distal end of the first side hole 24b. Consider a case in which the first thread-like element 16 is arranged between the outer catheter 24 and the inner catheter 22 over the entire axial region R, as described above. According to the present embodiment, the contact area between the first thread-like element 16 and the inner catheter 22 can be reduced compared to such a case, which is advantageous for reducing the withdrawal resistance of the inner catheter 22.

[0044] Each of the pair of thread-like parts 34 forms a first outer section 42, which is arranged outside the outer catheter 24 on a side closer to the distal end than the first side hole 24b. Consider a case in which the pair of thread-like parts 34 is arranged between the outer catheter 24 and the inner catheter 22 over the entire axial region R, as described above. According to the present embodiment, the contact area of ​​each of the pair of thread-like parts 34 with the inner catheter 22 can be reduced compared to such a case, which is advantageous for reducing the withdrawal resistance of the inner catheter 22.

[0045] If sagging occurs in the first thread-like element 16, it is likely that the first outer section 42 of the first thread-like element 16 will collide with an external object (for example, the endoscope or the like). To address this problem, according to the present embodiment, the retractable section 52 of the first thread-like element 16 is extended to the outside of the outer catheter 24. Therefore, when the delivery system 20 is outside the body, the retractable section 52 of the first thread-like element 16 is pulled towards its proximal end, in a position where it can be grasped by the surgeon's fingers, forceps, or the like; thus, any sagging of the first outer section 42 of the first thread-like element 16 can be eliminated, and a collision with an external object resulting from the sagging can be avoided.

[0046] Next, further features of the insertion system 20 will be described. The description will be made with reference to Fig. 4. The outer catheter 24 includes a receiving opening 60 that can receive the first coupling part 36A. In the present embodiment, the receiving opening 60 is formed by the first side hole 24b of the outer catheter 24. Alternatively, as further described below with reference to Fig. As described in Section 9, the receiving opening 60 is formed by the fourth side hole 24e, which is located further distally in the outer catheter 24 than the first side hole 24b. In any case, the receiving opening 60 penetrates the outer catheter 24 radially at a point that separates the first lumen 24a from the external space. The first coupling element 36A does not always have to be located in the receiving opening 60 to fulfill the condition "can receive" described herein. For example, if sagging has occurred in the first thread-like element 16, the first coupling element 36A can be pulled out of the receiving opening 60 to the outside of the outer catheter 24.The first coupling part 36A can be received in the receiving opening 60, for example, when the proximal end section of the first thread-like element 16 is pulled towards the proximal end face to exert a tensile force on the entire first thread-like element 16. When the insertion system 20 is inserted so that it passes through the lumen of an endoscope, the first coupling part 36A is received in the receiving opening 60, thereby suppressing an increase in frictional resistance due to contact between the lumen-forming surface of the endoscope and the first coupling part 36A.

[0047] When the first coupling part 36A is received in the receiving opening 60, it is provided in a section that connects continuously to an outer section located outside the outer catheter 24. In the present embodiment, the first outer section 42 described above serves as an example of the "outer section"; however, it could also be a different outer section that extends further towards the distal end than the first outer section 42. Furthermore, the "section that connects continuously," as described herein, is exemplified in the present embodiment by the first through-section 38 described above; however, it could also be a section that extends through the receiving opening 60, which is formed further towards the distal end than the first side hole 24b.Between the outer section and this section, which connects continuously to the outer section, there is no inner section located within the outer catheter 24. This advantage is explained.

[0048] Consider a case in which a section of the first thread-like element 16, which connects continuously to both sides in the longitudinal direction with respect to a section enclosing the first coupling part 36A, is an inner section located between the outer catheter 24 and the inner catheter 22. In this case, a section of the first thread-like element 16 rests against the inner surface of the outer catheter 24 at a point (inner section) that connects continuously to both sides in the longitudinal direction with respect to the first coupling part 36A, thus slightly restricting radial outward movement of the first coupling part 36A.This has the consequence that, when the inner catheter 22 is to be withdrawn, the problem arises that the state in which the first coupling part 36A is in contact with the inner catheter 22 is maintained without further ado, and the withdrawal resistance of the inner catheter 22 may be increased without further ado due to the first coupling part 36A.

[0049] Regarding this problem, according to the present embodiment, when the first coupling part 36A of the first thread-like element 16 is received in the receiving opening 60, the first coupling part 36A is provided in a section that connects continuously to the outer section located outside the outer catheter 24. Therefore, at a point where the first thread-like element 16 connects continuously to the outer side of the section in which it is provided, a portion of the first thread-like element 16 does not contact the inner surface of the outer catheter 24, thus facilitating the radial outward movement of the first coupling part 36A.This means that when the inner catheter 22 is to be withdrawn, the state in which the first coupling part 36A is in contact with the inner catheter 22 cannot be easily maintained, and an increase in the withdrawal resistance of the inner catheter 22 due to the first coupling part 36A can be avoided.

[0050] The dimensions of the receiving opening 60 are selected such that at least the first coupling element 36A of the first thread-like element 16 can pass through it. The receiving opening 60 of the present embodiment is an elongated slot that is long in the axial direction. Accordingly, the first coupling element 36A can be stably received in the receiving opening 60 even if the outer catheter 24 is displaced axially relative to the tube stent 10. The receiving opening 60 of the present embodiment extends straight along the axial direction. Alternatively, the receiving opening 60 can extend circumferentially at an angle to the axial direction. The minimum width of the receiving opening 60 in the lateral direction, perpendicular to the longitudinal direction, is designated W.The length of the receiving opening 60, as an elongated hole, is not subject to any special restrictions in the longitudinal direction, but it can, for example, be twice or more than the minimum width W.

[0051] The diameter of the first thread-like element 16 can be larger than the diameter of the second thread-like element 30. The diameter specified herein refers to the maximum diameter (m) in a cross-section orthogonal to the longitudinal direction of the first thread-like element 16. If the first thread-like element 16 has the coupling part 36A, the diameter of the first thread-like element 16 is the diameter at a point where the coupling part 36A is not present. To satisfy such a condition, the diameter of the first thread-like element 16 can be twice the diameter of the second thread-like element 30 or larger. Such a design can better ensure the strength of the first thread-like element 16 than in a case where the diameter of the first thread-like element 16 is equal to the diameter of the second thread-like element 30.Therefore, such a design is advantageous to prevent breakage of the first thread-like element 16 when the first thread-like element 16 is pulled to remove the tubular stent 10 placed in the body. Furthermore, the second thread-like element 30 can be made less prone to collisions with other elemental components than in a case where the diameter of the second thread-like element 30 is equal to the diameter of the first thread-like element 16. Second embodiment

[0052] A second embodiment of an introduction system 20 is described. In the following embodiment, the same details as in the first embodiment can be applied to the elementary components that were described in the first embodiment but are not described here.

[0053] The second embodiment is described with reference to Fig. 8 described. The insertion system 20 of the present embodiment differs from the first embodiment with respect to a second coupling part 36B, which is described below. The coupling parts 36A and 36B of the present embodiment include, in addition to the first coupling part 36A, a second coupling part 36B, which is provided in a section of the first thread-like element 16 located on the side of the proximal end. The second coupling part 36B is provided in the retractable section 52 of the first thread-like element 16. The dimensions of the second coupling part 36B are typically larger than the dimensions of the sections of the first thread-like element 16 that border the second coupling part 36B in the longitudinal direction.If the sections of the first thread-like element 16, which are longitudinally adjacent to the second coupling part 36B, are aligned in a straight line, the size of the second coupling part 36B referred to herein is the maximum outer diameter in a direction orthogonal to the direction along the straight line. By providing such a second coupling part 36B in the retractable section 52, the first thread-like element 16 can be easily grasped at a specific point on the second coupling part 36B with the surgeon's fingers, forceps, or the like. Such an effect can be achieved, for example, in a case where the retractable section 52 is grasped to prevent sagging of the first outer section 42 of the first thread-like element 16 when the delivery system 20 is located outside the body.Furthermore, such an effect can also be achieved in a case where the second coupling part 36B of the first thread-like element 16 is grasped to remove the tubular stent 10 from the first organ 12. The dimensions of the second coupling part 36B are chosen such that the second coupling part 36B fits through the first side hole 24b and the second side hole 24c of the outer catheter 24. Therefore, when the outer catheter 24 is to be separated from the tubular stent 10, a situation can be avoided in which the separation of the two is hindered by the second coupling part 36B becoming caught on one of the side holes 24b or 24c.

[0054] The second coupling part 36B of the present embodiment can be arranged in the second side hole 24c of the outer catheter 24. Accordingly, when the insertion system 20 is guided through the lumen of the endoscope, an increase in frictional resistance due to contact between the lumen-forming surface of the endoscope and the second coupling part 36B can be suppressed. Third embodiment

[0055] The third embodiment is described with reference to Fig.9 described. In the external catheter 24 of this embodiment, the fourth side hole 24e is positioned further towards the distal end than the first side hole 24b and is configured as a different side hole than the first side hole 24b. The first thread-like element 16 of this embodiment is positioned further towards the distal end than the first outer section 42 and connects continuously to the first outer section 42. The first thread-like element 16 of this embodiment includes a third passage section 62 that passes through the fourth side hole 24e. The first outer section 42 of the first thread-like element 16 differs from that of the first embodiment and is provided only in a portion of the axial region R from the distal end of the external catheter 24 to the first side hole 24b.

[0056] The receiving opening 60 can, as in this embodiment, be formed by the fourth side hole 24e instead of by the first side hole 24b in the first embodiment. The first coupling element 36A, which couples the pair of thread-like parts 34 of the first thread-like element 16, can be received in the receiving opening 60. In this case, the receiving opening 60 can be provided at the distal end of the outer catheter 24, as in this embodiment. In this case, the receiving opening 60 can open axially towards the side of the tube stent 10, as in this embodiment.

[0057] Next, modified aspects of the elementary components explained above will be described.

[0058] The specific method of permanently connecting the first thread-like element 16 to the tubular stent 10 is not subject to any particular restrictions. For example, a connecting end of the first thread-like element 16 can be permanently connected to a part of the tubular stent 10 by a knot or the like.

[0059] Furthermore, one of the pair of thread-like parts 34 can form the first outer section 42 of the first thread-like element 16, and the other thread-like part 34 can be arranged inside the outer catheter 24 in the axial region R described above. Additionally, one of the pair of thread-like parts 34 can be arranged inside the tubular stent 10, while the other thread-like part 34 is not arranged inside the tubular stent 10.

[0060] The first thread-like element 16 need not be provided with one or both of the first and second coupling parts 36A and 36B. If necessary, the first thread-like element 16 may, for example, only include the second coupling part 36B.

[0061] The receiving opening 60 does not have to be an elongated hole. Furthermore, the shape of the receiving opening 60 is not subject to any particular restrictions, and it can have various shapes, such as a circular hole, a semicircular hole, or a rectangular hole.

[0062] The delivery system 20 need not be provided with the second thread-like element 30. The size ratio between the diameter of the first thread-like element 16 and the diameter of the second thread-like element 30 is not subject to any particular restrictions, and both can be the same size. The specific structure for the releasable coupling of the tubular stent 10 and the external catheter 24 by means of the second thread-like element 30 is not subject to any particular restrictions, and various structures, including known structures, can be adopted. Furthermore, in the first embodiment, the inner catheter 22 also forms a release element that, by means of a pulling action, can release the connection between the external catheter 24 and the tubular stent 10 via the second thread-like element 30. This release element can be provided separately from the inner catheter 22.

[0063] The details of the individual elementary components described in the preceding embodiments are merely examples. Technical concepts derived from abstracting these details should not be interpreted as being limited to the content of this description. Moreover, numerous design modifications, such as variations, additions, and omissions, can be made to the details of the elementary components described in the embodiments. The details that may be subject to such design modifications are highlighted by the addition of the notations "present embodiment" and "execution form." However, design modifications are also permissible without such notations. Any combination of the elementary components described above is also effective. The hatching shown in the sectional views of the drawings does not restrict the material of the hatched object. Industrial applicability

[0064] This disclosure relates to a contribution system. List of reference symbols

[0065] 10: Tube stent, 16: First thread-like element, 20: Delivery system, 22: Inner catheter, 24: Outer catheter, 24b: First side hole, 24c: Second side hole, 30: Second thread-like element, 34: Thread-like part, 36A: First coupling part, 36B: Second coupling part, 38: First through-section, 40: First inner section, 42: First outer section, 48: Second inner section, 52: Retractable section. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2012-239803 A

[0003]

Claims

[1] Contribution system, comprising: an internal catheter; an external catheter through which the internal catheter is passed and in which a first side hole is formed; a tubular stent positioned at the distal end relative to the outer catheter, with the inner catheter passing through the tubular stent; and a first thread-like element that is inseparably connected to the tubular stent, wherein at least one section of the first thread-like element runs between the inner catheter and the outer catheter on a side that is closer to the proximal end than the first side hole, wherein the first thread-like element is passed through the first side hole and is positioned outside the external catheter in at least part of an axial area from the distal end of the external catheter to the first side hole. [2] Delivery system according to claim 1, wherein the first thread-like element includes: a first passage section that passes through the first side hole; a first inner section that connects continuously to the first through section and runs between the inner catheter and the outer catheter on the side that is closer to the proximal end than the first side hole; and a first outer section that connects continuously to the first through section and is located outside the outer catheter on a side that is closer to the distal end than the first lateral hole. [3] Delivery system according to claim 2, wherein the first thread-like element includes a return section connected to the tube stent and a pair of thread-like parts connected to the return section and Each of the pair of thread-like parts forms the first outer section. [4] Delivery system according to claim 3, wherein a section of each of the pair of thread-like parts is arranged inside the tubular stent. [5] Delivery system according to any one of claims 2 to 4, wherein the first thread-like element includes a return section connected to the tubular stent and a pair of thread-like parts connected to the return section and the first thread-like element includes a coupling part that couples the pair of thread-like parts. [6] Delivery system according to claim 5, wherein the outer catheter includes a receiving opening that can receive the coupling part and is formed by the first side hole or another side hole formed in the outer catheter on a side closer to the distal end than the first side hole, and The coupling part, when received in the receiving aperture, is provided in a section that connects continuously to an outer section of the first thread-like element, the outer section being located outside the outer catheter. [7] Insertion system according to claim 6, wherein the receiving opening is an elongated hole which is long in the axial direction. [8] Delivery system according to any one of claims 2 to 7, wherein a second side hole is formed in the outer catheter on a side that is closer to the proximal end than the first side hole, and The first thread-like element has a pull-out section that is pulled out of the second side hole to the outside of the external catheter. [9] Delivery system according to claim 8, wherein the first thread-like element includes a return section connected to the tubular stent and a pair of thread-like parts connected to the return section, the first thread-like element includes a coupling part that couples the pair of thread-like parts, and The coupling part is provided on the extendable section. [10] Delivery system according to one of claims 2 to 9, further comprising a second thread-like element that detachably connects the tube stent and the external catheter. [11] Delivery system according to claim 10, wherein the diameter of the first thread-like element is larger than the diameter of the second thread-like element.

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