Stent delivery device

Abstract

This stent delivery device 100 is configured in a manner such that: an engagement state in which a locking claw 42 engages a lockable part 32 is released by moving the locking claw 42 in a first direction with respect to a lockable surface 33; an attachable part 40 is detached from a main body part 30 by withdrawing the attachable part 40 in a second direction intersecting the first direction while in the state in which the engagement state in which the locking claw 42 engages the lockable part 32 has been released; and when an operation-receiving part 45 is operated in a direction including a second-direction component and an intersecting-direction component, the locking claw 42 slides with respect to the lockable part 32 in a direction opposite the intersecting direction while maintaining the engagement state of engaging the lockable part 32.

Description

Stent delivery device

[0001] The present invention relates to a stent delivery device.

[0002] As a stent delivery device used for implanting a stent into a body cavity, for example, there is one described in Patent Document 1. The stent delivery device of Patent Document 1 includes a long sheath that holds a stent restrained in a reduced-diameter state by a restraining wire at its distal end, and the stent is released from the restrained state by the restraining wire by pulling out the restraining wire to the proximal end side.

[0003] Japanese Patent Application Laid-Open No. 2005-304792

[0004] According to the study by the inventor of the present application, the stent delivery device of Patent Document 1 still has room for improvement from the viewpoint of implanting the stent at a more reliable intended timing.

[0005] The present invention has been made in view of the above problems, and provides a stent delivery device having a structure capable of implanting a stent at a more reliable intended timing.

[0006] According to the present invention, a delivery device capable of transporting a stent comprises: a long sheath that holds the stent, which is constrained in a reduced diameter state by a restraining thread, at its tip; a release operation unit provided at the base end of the sheath for pulling the restraining thread towards the base end to release the stent from the restrained state by the restraining thread; the release operation unit comprises: a main body; a detachable part detachably provided to the main body and used with the base end portion of the restraining thread connected to it; the detachable part comprises: a locking claw that is locked to the main body; and an operation receiving part that receives operation by a user; the main body has a locked portion to which the locking claw is locked; and the engagement of the locking claw with respect to the locked portion is released when the locking claw moves in a first direction relative to the locked portion. A stent delivery device is provided in which, when the engagement of the locking claw with the locked portion is released, the detachable portion is pulled out in a second direction intersecting the first direction, thereby detaching the detachable portion from the main body, and when the operating receiving portion is operated in a direction including the second direction component and the intersecting direction component which is a direction intersecting the first plane which is a plane including the first and second directions, the locking claw slides against the locked portion in the opposite direction to the intersecting direction while maintaining its engagement with the locked portion.

[0007] According to the present invention, stents can be placed more reliably at the intended timing.

[0008] This is a schematic overall view of the stent delivery device according to the embodiment. This is a schematic cross-sectional view showing the tip of the stent delivery device according to the embodiment. This is a diagram for explaining the operation of the stent delivery device according to the embodiment, showing the state in which the attachment / detachment part is detached from the main body and the restraint thread is pulled out towards the proximal end. Figures 4(a) and 4(b) are diagrams for explaining the operation of the stent delivery device according to the embodiment, of which Figure 4(a) is a cross-sectional view showing the attachment / detachment part and its surrounding structure, and Figure 4(b) is a view of the attachment / detachment part viewed from the radially outer side. Figures 5(a), 5(b), and 5(c) are cross-sectional views for explaining the operation of the stent delivery device according to the embodiment, of which Figure 5(a) shows the state in which the locking claw is locked to the main body, Figure 5(b) shows the state in which the engagement of the locking claw with the locked surface is released, and Figure 5(c) shows the state in which the attachment / detachment part is detached from the main body. Figures 6(a) and 6(b) illustrate the operation of the stent delivery device according to the embodiment. Figure 6(a) shows the proximal end of the stent released from the restraint by the restraint thread, and Figure 6(b) shows the first detachable part separated from the main body. Figures 7(a) and 7(b) illustrate the operation of the stent delivery device according to the embodiment. Figure 7(a) shows the tip of the stent released from the restraint by the restraint thread, and Figure 7(b) shows the second detachable part separated from the main body. Figures 8(a) and 8(b) illustrate the operation of the stent delivery device according to the embodiment. Figure 8(a) shows the middle part of the stent released from the restraint by the restraint thread, and Figure 8(b) shows the third detachable part separated from the main body. Figures 9(a) and 9(b) show the release operation section in the embodiment, where Figure 9(a) is a perspective view of the release operation section viewed from the tip side, and Figure 9(b) is a side view of the release operation section viewed in the radial direction. Figures 10(a) and 10(b) show the release operation section in the embodiment, where Figure 10(a) is a perspective view of the release operation section viewed from the base end side, and Figure 10(b) is a rear view of the release operation section viewed from the base end side. Figure 11(a) is a cross-sectional view along the line A-A shown in Figure 9(b), and Figure 11(b) is a partially enlarged view showing the locking claw and its surrounding structure.Figure 12(a) is a cross-sectional view of the release operation section in the embodiment, Figure 12(b) is a partially enlarged view of section A shown in Figure 12(a), and Figure 12(c) is a partially enlarged view of the cross section along line A-A shown in Figure 11(a). Figure 13(a) is a partially enlarged view of section B shown in Figure 12(b), and Figure 13(b) is a partially enlarged view of section C shown in Figure 12(c). Figure 14(a) is a perspective view of the detachable section in the embodiment, and Figure 14(b) is a partially enlarged view of section A shown in Figure 14(a). Figures 15(a) and 15(b) show the detachable section in the embodiment, of which Figure 15(a) is a side view and Figure 15(b) is a front view of the detachable section viewed from the tip side. Figures 16(a) and 16(b) show the attachment / detachment portion in the embodiment, where Figure 16(a) is a view of the attachment / detachment portion from the radially outer side and Figure 16(b) is a view of the attachment / detachment portion from the radially inner side. Figure 17(a) is a side view showing the internal structure of the first member of the main body in the embodiment, and Figure 17(b) is a perspective view showing the guide surface and its surrounding structure. This is a front view showing the locking claw and its surrounding structure in the embodiment, viewed from the tip side. Figure 19(a) shows the state in which the locking claw has moved in the first direction from the state shown in Figure 18, and Figure 19(b) shows the state in which the locking claw has moved in the opposite direction to the intersecting direction from the state shown in Figure 18. This is a cross-sectional view along the line D-D shown in Figure 12(c). Figure 21(a) shows the state in which the attachment / detachment portion has moved in the second direction from the state shown in Figure 20, and Figure 21(b) shows the state in which the operating receiver has been operated in the intersecting direction from the state shown in Figure 20. Figures 22(a) and 22(b) are schematic plan views showing the main body side contact portion and the detachable side contact portion in the embodiment. Figure 22(a) shows the state before the position of the detachable portion relative to the main body is shifted, and Figure 22(b) shows the state after the position of the detachable portion relative to the main body has been shifted in the third direction. Figures 23(a) and 23(b) are schematic front views showing the main body side contact portion and the detachable side contact portion in the embodiment. Figure 23(a) shows the state before the position of the detachable portion relative to the main body is shifted, and Figure 23(b) shows the state after the position of the detachable portion relative to the main body has been shifted in the third direction.Figures 24(a) and 24(b) are schematic perspective views showing the main body side contact portion and the detachable side contact portion in the embodiment. Figure 24(a) shows the state before the position of the detachable portion relative to the main body is shifted, and Figure 24(b) shows the state after the position of the detachable portion relative to the main body has been shifted in the third direction. This figure is for explaining the transmission of force when detaching the detachable portion from the main body in the embodiment, and is a view of the detachable portion from the radially outer side.

[0009] Embodiments of the present invention will be described below with reference to Figures 1 to 25. In all drawings, the same reference numerals are used for similar components, and descriptions are omitted as appropriate. Figures 5(a), 5(b), 5(c), 4(a), 4(b), and 10(a) are cross-sectional views along the first plane 310a shown in Figure 9(a). In Figure 12(a), the locking portion 32 and its surrounding structure of the main body 30 are selectively shown in a cross-sectional view along the first plane 310a. The various components of the stent delivery device 100 of the present invention do not need to be independent entities. It is permissible for multiple components to be formed as a single member, for one component to be formed from multiple members, for one component to be part of another component, for a part of one component to overlap with a part of another component, etc. In the following, the distal side of the stent delivery device 100 will be referred to as the tip side, and its proximal side as the proximal end side. Furthermore, the tip refers to a certain range including the distal end (frontmost point) and its surroundings, while the proximal end refers to a certain range including the proximal end (very basal point) and its surroundings.

[0010] The stent delivery device 100 according to this embodiment is a delivery device capable of transporting a stent 200, and includes a long sheath (in this embodiment, an outer sheath 10 and an inner sheath 60) that holds the stent 200, which is constrained in a reduced diameter state by a restraining thread 250, at its tip, and a release operation unit 20 provided at the base end of the sheath for performing an operation to pull the restraining thread 250 towards the base end and release the stent 200 from the restrained state by the restraining thread 250.

[0011] The release operation unit 20 includes a main body 30 and a detachable unit 40 that is detachably provided to the main body 30 and is used when the base end portion 251 of the restraint thread 250 is connected to it. The detachable unit 40 includes a locking claw 42 that is locked to the main body 30 and an operation receiving unit 45 that receives operation by the user. The main body 30 has a locked portion 32 to which the locking claw 42 is locked, and when the locking claw 42 moves in a first direction relative to the locked surface 33 (for example, in the direction of arrow A shown in Figure 4(a), etc.), the engagement of the locking claw 42 with respect to the locked portion 32 is released. With the engagement of the locking claw 42 with respect to the locked portion 32 released, the detachable portion 40 is pulled out in a second direction intersecting the first direction (for example, the direction of arrow C shown in Figure 4(a), etc.), thereby detaching the detachable portion 40 from the main body portion 30 (see Figures 3, 5(a), 5(b), and 5(c), etc.). When the operating receiving portion 45 is operated in a direction that includes a component in the second direction and a component in the intersecting direction (for example, the direction of arrow D shown in Figure 4(b), etc., which may hereinafter simply be referred to as the "intersecting direction") which is a direction that intersects with the first plane 310 (see Figure 4(b)), which is a plane that includes the first and second directions, the locking claw 42 slides against the locked portion 32 in the opposite direction to the intersecting direction (for example, the direction of arrow E shown in Figure 19(b), etc., which may hereinafter simply be referred to as the "opposite direction") while maintaining its engaged state with the locked portion 32 (see Figures 18 and 19(b)).

[0012] In this context, "the locking claw 42 slides relative to the locked portion 32 in a direction opposite to the intersecting direction" means that the locking claw 42 slides in a direction that includes at least a component opposite to the intersecting direction.

[0013] As shown in Figures 6(a) to 8(b), by operating the operating receiving portion 45 in a specific operating direction (in this embodiment, a direction that includes a component in the first plane 310 and a component in the second direction and a component in the radially outward direction of the main body portion 30, and may hereinafter simply be referred to as the "specific operating direction"), the engagement of the locking claw 42 with the locked portion 32 can be released, and the detachable portion 40 can be detached from the main body portion 30. As shown in Figure 3, by pulling the detached detachable portion 40 toward the base end, the restraining thread 250 can be pulled toward the base end, and the stent 200 can be released from the restraint state imposed by the restraining thread 250.

[0014] According to this embodiment, when the operating receiving portion 45 is operated in a specific operating direction, the detachable portion 40 detaches from the main body portion 30. On the other hand, when the operating receiving portion 45 is operated in a direction that includes a component in the second direction and a component in the intersecting direction which is a direction that intersects with the first plane 310, which is a plane that includes the first and second directions, the engagement state of the locking claw 42 with the locked portion 32 is maintained, and the detachable portion 40 does not detach from the main body portion 30. In other words, when the operating receiving portion 45 is operated in a specific operating direction, the detachable portion 40 detaches from the main body portion 30, the restraining thread 250 is pulled out towards the base end, and the stent 200 is released from the restraint state imposed by the restraining thread 250. On the other hand, when the operating receiving portion 45 is operated in a direction different from the specific operating direction, the engagement state of the locking claw 42 with the locked portion 32 is maintained, and the pulling out of the restraining thread 250 towards the base end is suppressed. Therefore, the stent 200 can be placed more reliably at the intended timing.

[0015] Furthermore, the statement here that "when operated in a direction that includes the component in the second direction and the component in the intersecting direction, the engagement state of the locking claw 42 with the locked portion 32 is maintained" means that when the operating receiving portion 45 is operated in a direction that includes the component in the second direction and the component in the intersecting direction, the engagement state of the locking claw 42 with the locked portion 32 is more easily maintained compared to when it is operated in a specific operating direction.

[0016] Furthermore, in this embodiment, the release operation unit 20 includes a position shift unit 50 (Figures 20, 21(a), and 21(b)) that shifts the position of the attachment / detachment unit 40 relative to the main body unit 30 when the operation receiving unit 45 is operated in an intersecting direction, which is a direction that intersects with respect to the first plane 310, which is a plane that includes the first and second directions. The position shift unit 50 has a main body side contact unit 51 on the main body unit 30 and an attachment / detachment side contact unit 56 on the attachment / detachment unit 40, and the attachment / detachment side contact unit 56 receives a reaction force from the main body side contact unit 51, thereby shifting the position of the attachment / detachment unit 40 relative to the main body unit 30 (see Figures 21(b), 22(a) to 24(b)). The direction in which the position shift unit 50 shifts the attachment / detachment unit 40 is a direction that includes a component of the third direction, which is the opposite direction to the first direction.

[0017] With this configuration, if the operating receiver 45 is operated in a crossing direction, even if the locking claw 42 moves in a first direction relative to the locked portion 32 (for example, even if the detachable portion 40 swings in a forward-tilting direction as shown in Figure 5(b)), the detachable portion 40 and thus the locking claw 42 are shifted in a direction that includes a component in a third direction, thereby canceling out the movement in the first direction and maintaining the engagement state of the locking claw 42 with the locked portion 32. That is, if the operating receiver 45 is operated in a specific operating direction, the detachable portion 40 detaches from the main body 30, the restraining thread 250 is pulled out towards the base end, and the stent 200 is released from the restraint state imposed by the restraining thread 250. On the other hand, if the operating receiver 45 is operated in a direction different from the specific operating direction, the engagement state of the locking claw 42 with the locked portion 32 is maintained, and the pulling out of the restraining thread 250 towards the base end is suppressed. Therefore, the stent 200 can be placed more reliably at the intended timing. In such cases, the stent delivery device 100 does not necessarily have to be configured such that, when the operating receiver 45 is operated in a direction including a second direction component and a crossing direction component, the locking claw 42 slides relative to the locked portion 32 in the opposite direction to the crossing direction while maintaining its engagement with the locked portion 32. Even in such cases, when the operating receiver 45 is operated in a direction different from the specific operating direction, even if the locking claw 42 moves in the first direction relative to the locked portion 32, the position shifting unit 50 shifts the detachment unit 40 and thus the locking claw 42 in a direction including a third direction component as described above, thereby canceling out the movement in the first direction. This makes it possible to maintain the engagement state of the locking claw 42 with the locked portion 32 (compared to when it is operated in a specific operating direction, it is easier to maintain the engagement state of the locking claw 42 with the locked portion 32).

[0018] Furthermore, the statement here that "when the operating receiving portion 45 is operated in a crossing direction, the engagement state of the locking claw 42 with the locked portion 32 is maintained" means that when the operating receiving portion 45 is operated in a crossing direction, the engagement state of the locking claw 42 with the locked portion 32 is more easily maintained compared to when it is operated in a specific operating direction.

[0019] However, in the present invention, the stent delivery device 100 does not need to be equipped with a position shifting section 50. Even in such a case, when the operating receiving section 45 is operated in a direction different from the specific operating direction, the locking claw 42 slides against the locked section 32 in the opposite direction to the intersecting direction while maintaining its engagement with the locked section 32, as described above. Therefore, it is possible to prevent the detachment section 40 from separating from the main body section 30.

[0020] As shown in Figure 1, the stent delivery device 100 comprises an outer sheath 10 and an inner sheath 60 that is axially slidable through the outer sheath 10. Furthermore, the stent delivery device 100 includes a handle 80 to which the base end 10a of the outer sheath 10 is fixed, and an inner shaft 70 that is integrated with the inner sheath 60 and extends from the handle 80 toward the base end, with a release operation part 20 fixed to the base end of the inner shaft 70.

[0021] As shown in Figure 2, the tip of the inner sheath 60 holds the stent 200, which is constrained in a reduced diameter state by the restraining thread 250, and the stent 200 is housed in a reduced diameter state between the inner circumferential surface of the outer sheath 10 and the outer circumferential surface of the inner sheath 60. When implanting the stent 200 in a body cavity, with the outer sheath 10 and inner sheath 60 inserted into the desired location in the body cavity along a guide wire (not shown), the handle 80 is retracted toward the release operation unit 20 together with the outer sheath 10, exposing the tip of the inner sheath 60 and, consequently, the stent 200 from the outer sheath 10. In this state, an operation is performed on the release operation unit 20 to pull out the restraining thread 250 toward the proximal end, thereby releasing the stent 200 from the restrained state imposed by the restraining thread 250.

[0022] In this embodiment, as an example, the length of the restraining thread 250 from the stent 200 to the attachment / detachment portion 40 is set so that the restraint by the restraining thread 250 is released when the attachment / detachment portion 40 is pulled in the second direction (or a direction including a component of the second direction) with a sufficient amount of traction. In other words, the restraining thread 250 has sufficient slack in its length so that the restraint of the restraining thread 250 on the stent 200 is maintained when the amount of traction in the second direction (or a direction including a component of the second direction) is less than a predetermined amount. However, the present invention is not limited to this example, and the length of the restraining thread 250 from the stent 200 to the attachment / detachment portion 40 may be set so that the restraint by the restraining thread 250 is released quickly when the attachment / detachment portion 40 is pulled in the second direction (same as above) (i.e., the restraining thread 250 may have substantially no slack in its length or a configuration in which there is little slack in its length).

[0023] More specifically, for example, different sections in the axial direction of the stent 200 are individually restrained by a plurality of restraining threads 250 (in this embodiment, a first restraining thread 250a, a second restraining thread 250b, and a third restraining thread 250c). Also, as shown in Figures 6(a) to 8(b), the release operation unit 20 has the same number of attachment / detachment units 40 as the plurality of restraining threads 250 (in this embodiment, a first attachment / detachment unit 40a, a second attachment / detachment unit 40b, and a third attachment / detachment unit 40c), and a plurality of locking units 32 corresponding to each attachment / detachment unit 40 (in this embodiment, a first locking unit 32a, a second locking unit 32b, and a third locking unit 32c).

[0024] The proximal end 230 of the stent 200 is restrained by the first restraining thread 250a, the tip 210 of the stent 200 is restrained by the second restraining thread 250b, and the middle portion 220 of the stent 200 is restrained by the third restraining thread 250c. Furthermore, the proximal end portion 251 of the first restraining thread 250a is connected to the first attachment / detachment portion 40a, the proximal end portion 251 of the second restraining thread 250b is connected to the second attachment / detachment portion 40b, and the proximal end portion 251 of the third restraining thread 250c is connected to the third attachment / detachment portion 40c.

[0025] As shown in Figures 6(a) and 6(b), by detaching the first detachable part 40a from the main body 30, the first restraining thread 250a can be pulled out towards the base end, and the base end 230 of the stent 200 can be released from the restrained state by the first restraining thread 250a. Similarly, as shown in Figures 7(a) and 7(b), by detaching the second detachable part 40b from the main body 30, the second restraining thread 250b can be pulled out towards the base end, and the tip 210 of the stent 200 can be released from the restrained state by the second restraining thread 250b. As shown in Figures 8(a) and 8(b), by detaching the third detachable part 40c from the main body 30, the third restraining thread 250c can be pulled out towards the base end, and the middle part 220 of the stent 200 can be released from the restrained state by the third restraining thread 250c. In this way, different sections of the stent 200 in the axial direction can be individually deformed from a reduced diameter state to an expanded state at desired timings, allowing the stent 200 to be placed in a desired location within the body cavity.

[0026] The contracted state of the stent 200 refers to a state in which the stent 200 is compressed radially to the extent that it can be accommodated between the inner surface of the outer sheath 10 and the outer surface of the inner sheath 60, while the expanded state of the stent 200 refers to a state in which the stent 200 has expanded radially from the above-mentioned contracted state.

[0027] The stent 200 is a cylindrical body with a mesh structure made of wires. The material of the wires constituting the stent 200 is not particularly limited and may be a metal material or a resin material. The restraint threads 250 (first restraint threads 250a to third restraint threads 250c) may be, for example, threads made of resin material or threads (wires) made of metal material. In Figures 1, 2, 6(a), 7(a), and 8(a), the first restraint thread 250a is shown as a dotted line, the second restraint thread 250b as a solid line, and the third restraint thread 250c as a dashed line. Also, in Figures 1, 2, 6(a), 7(a), and 8(a), the binding shape of the restraint threads 250 is shown in a simplified rhombus grid shape.

[0028] The outer sheath 10 is a long, hollow tubular member. The inner sheath 60 is inserted into the lumen of the outer sheath 10, and the outer sheath 10 is slidable in its axial direction relative to the inner sheath 60. The inner sheath 60 is a long, hollow tubular member. The outer diameter of the inner sheath 60 is smaller than the inner diameter of the outer sheath 10, and the inner sheath 60 is inserted into the lumen of the outer sheath 10. The tip of the inner sheath 60 constitutes the placement section 61a where the stent 200 is positioned. The stent 200 is restrained in a reduced diameter state by the restraint thread 250 while it is externally fitted into the placement section 61a of the inner sheath 60. The base end of the inner sheath 60 is connected to the tip of the inner shaft 70.

[0029] A tip 63 (see Figures 1 and 2) is provided at the leading edge of the inner sheath 60. The tip 63 is formed in a conical shape, for example, with a diameter that gradually decreases towards the tip. The lumen of the tip 63 and the lumen of the inner sheath 60 are in communication with each other. When inserting the stent delivery device 100 into a body cavity, the guidewire, which has been previously inserted into the body cavity, is inserted into the lumen of the inner sheath 60 through the opening at the tip of the tip 63. This allows the outer sheath 10 and the inner sheath 60 to be inserted into the body cavity along the guidewire 300. In this embodiment, for example, when the handle 80 is advanced toward the tip 63 together with the outer sheath 10, the tip surface of the outer sheath 10 comes into contact with the base end surface of the tip 63, thereby restricting further advancement of the outer sheath 10 and also restricting further advancement of the handle 80, which is integrated with the outer sheath 10.

[0030] A stent retraction restricting portion 68 (see Figure 2, etc.) is provided on the outer circumference of the inner sheath 60. The outer diameter of the stent retraction restricting portion 68 is larger than the outer diameter of the inner sheath 60. The stent retraction restricting portion 68 is positioned on the proximal end side of the arrangement section 61a. The stent retraction restricting portion 68 restricts the stent 200 from being displaced on the proximal end side of the arrangement section 61a as the outer sheath 10 retracts.

[0031] The handle 80 is a hollow component, for example, formed in a cylindrical shape. The inner shaft 70 is slidably inserted into the inside of the handle 80, and by moving the handle 80 along the inner shaft 70 toward the release operation section 20, the base end 10a of the outer sheath 10 can also be retracted toward the release operation section 20 along the inner shaft 70. The base end 10a of the outer sheath 10 is introduced into the inside of the handle 80 and is positioned along the axial direction of the handle 80.

[0032] The inner shaft 70 is formed, for example, as a long tube in one direction. The inner sheath 60 and the inner shaft 70 are fixed to each other by press-fitting the tip of the inner shaft 70 into the base end of the inner sheath 60. The inner shaft 70 is made of a metal material such as stainless steel (SUS).

[0033] As described above, the release operation unit 20 has a main body 30 and a detachable unit 40 that is detachably provided to the main body 30 and is used with the base end portion of the restraint thread 250 connected to it.

[0034] The main body portion 30 is a hollow member and is formed, for example, in a cylindrical shape. The main body portion 30 is connected to the base end side of the inner shaft 70.Hereinafter, in the description of the release operation portion 20 (main body portion 30 and detachment portion 40), the left side in Figure 9(b) will be referred to as the tip side or front side, and the right side in Figure 9(b) will be referred to as the base end side or rear side.In addition, the circumferential direction of the main body portion 30 may be simply referred to as the circumferential direction, the axial direction of the main body portion 30 may be simply referred to as the axial direction, and the radial direction of the main body portion 30 may be simply referred to as the radial direction.In addition, the side of the main body portion 30 in the radial direction toward the central axis 350 may be simply referred to as the inside or inward, and the side of the main body portion 30 in the radial direction toward the central axis 350 may be simply referred to as the outside or outward.The main body portion 30 has, for example, a first member 30a and a second member 30b, and is constructed by assembling the first member 30a and the second member 30b together.

[0035] As shown in Figures 11(a) and 17(a), a flat disc portion 31 is formed on the inner surface of the first member 30a. The outer shape of the disc portion 31, viewed from the tip side, is approximately circular. Each surface of the disc portion 31 is formed flat and is perpendicular to the central axis 350 of the main body portion 30.

[0036] As shown in Figure 17(a), the first member 30a further includes a peripheral wall portion 38 formed in a circumferential manner along the outer peripheral edge of the disc portion 31, a first cylindrical portion 36 formed in the center of the disc portion 31, and a second cylindrical portion 37 positioned towards the tip of the first cylindrical portion 36. The peripheral wall portion 38 protrudes from the base end surface of the disc portion 31 toward the base end. The first cylindrical portion 36 protrudes toward the base end than the peripheral wall portion 38. The first cylindrical portion 36 is formed in a substantially cylindrical shape coaxial with the central axis 350 of the main body portion 30. Similarly, the second cylindrical portion 37 is formed in a substantially cylindrical shape coaxial with the central axis 350 of the main body portion 30. The base end of the inner shaft 70 is inserted through the inner cavity of the first cylindrical portion 36 and the inner cavity of the second cylindrical portion 37.

[0037] Here, as shown in Figure 11(a), the release operation unit 20 has a plurality of attachment / detachment parts 40 (first attachment / detachment part 40a to third attachment / detachment part 40c) distributed around the central axis 350 of the main body part 30, and a plurality of locking parts 32 (first locking part 32a to third locking part 32c) corresponding to each attachment / detachment part 40.

[0038] More specifically, the disc portion 31 has the same number of openings 35 (in this embodiment, a first opening 35a, a second opening 35b, and a third opening 35c) as the number of attachment / detachment portions 40 distributed around the central axis 350 of the main body portion 30. In this embodiment, the openings 35 and a portion of their peripheral edges constitute the locking portion 32. More specifically, of the multiple openings 35, the first opening 35a and a portion of its peripheral edge constitute the first locking portion 32a, the second opening 35b and a portion of its peripheral edge constitute the second locking portion 32b, and the third opening 35c and a portion of its peripheral edge constitute the third locking portion 32c.

[0039] Each of the multiple openings 35 penetrates the disc portion 31 in the thickness direction. Each of the multiple openings 35 is formed rotationally symmetrically with respect to the central axis 350. Furthermore, each of the multiple openings 35 (same as above) is arranged at equal angular intervals in the circumferential direction of the main body portion 30. In the radial direction, the multiple openings 35 are located between the inner circumferential surface of the peripheral wall portion 38 and the outer circumferential surface of the first cylindrical portion 36. Also, on the base end side surface of the disc portion 31, the same number of partition wall portions 39 as the multiple openings 35 are erected between the inner circumferential surface of the peripheral wall portion 38 and the first cylindrical portion 36 (see Figures 3, 10(b), and 17(a), etc.). Each partition wall portion 39 divides the gap between the inner circumferential surface of the peripheral wall portion 38 and the outer circumferential surface of the first cylindrical portion 36 into a region where the first detachable portion 40a is located, a region where the second detachable portion 40b is located, and a region where the third detachable portion 40c is located. The plate surface of each partition wall portion 39 is oriented in the circumferential direction of the main body portion 30. Each partition wall portion 39 is formed rotationally symmetrically with respect to the central axis 350. Furthermore, each partition wall portion 39 is arranged at equal angular intervals in the circumferential direction of the main body portion 30. The tip of the outer edge of each partition wall portion 39 is connected to the inner circumferential surface of the peripheral wall portion 38. The inner edge of each partition wall portion 39 is connected to the outer circumferential surface of the first cylindrical portion 36. As shown in Figure 10(b), the multiple detachable portions 40 are arranged in the circumferential direction between adjacent partition wall portions 39 and at equal angular intervals.

[0040] In this embodiment, the multiple attachment / detachment parts 40 (first attachment / detachment parts 40a to third attachment / detachment parts 40c) are set to have the same shape and dimensions as each other. As shown in Figure 15(a), each attachment / detachment part 40 has, in addition to the locking claw 42 and operating receiving part 45 described above, a thread connecting part 47 to which the corresponding restraining thread 250 is connected, a main part 41 on which the thread connecting part 47 is formed, a tip side wall-like part 48a located on the tip side of the main part 41, and a base end side wall-like part 48b located on the base end side of the main part 41.

[0041] The main part 41 is formed, for example, in a substantially semi-cylindrical shape, and its axis is aligned along the central axis 350. The outer surface of the main part 41 is formed in a curved shape that is convex toward the radially outward direction. On the other hand, the inner surface of the main part 41 is, for example, a substantially flat surface and is perpendicular to the radial direction. Note that the term "semi-cylindrical shape" here is not limited to a shape in which a cylinder is divided in half along its outer diameter, but also includes shapes in which a cylinder is divided into multiple parts in the circumferential or radial direction.

[0042] As shown in Figure 12(b), the thread connecting portion 47 protrudes radially inward from the inner surface of the main portion 41. The thread connecting portion 47 has a cylindrical shaft portion 47a with the radial direction as the axial direction, and a flange portion 47b that extends radially outward from the tip of the shaft portion 47a (the tip in the direction of protrusion of the shaft portion 47a). When viewed radially, each of the shaft portion 47a and the flange portion 47b has a substantially elliptical shape that is elongated in the circumferential direction. As shown in Figure 5(a), the base end portion 251 of the restraining thread 250 is wound around and fixed to the shaft portion 47a.

[0043] The tip side wall portion 48a is connected to the tip edge of the main portion 41. As shown in Figure 15(b), the tip side wall portion 48a, viewed from the tip side, is formed in a substantially fan shape centered on the central axis 350. The outer and inner circumferential surfaces of the tip side wall portion 48a are curved surfaces that are convex radially outward. As shown in Figure 15(a), the tip surface of the tip side wall portion 48a is formed flat and perpendicular to the central axis 350. On the other hand, the base end surface of the tip side wall portion 48a is a stepped surface. As shown in Figures 16(a) and 16(b), in the circumferential direction, the dimensions of the tip side wall portion 48a are larger than those of the main portion 41, and the tip side wall portion 48a protrudes from the main portion 41 in one and the other circumferential directions, respectively.

[0044] As shown in FIGS. 14(a) to 16(b) etc., in the case of this embodiment, the locking claw 42 is formed on the surface on the tip side of the tip side wall-like portion 48a. More specifically, the locking claw 42 includes an extension pin 43 that extends in a direction having a direction component on the opposite side to the second direction (in the case of this embodiment, the direction component on the tip side), and a claw portion 44 provided at the tip end portion in the extending direction of the extension pin 43 and engaging with the engaged portion 32.

[0045] The extension pin 43 extends from the surface on the tip side of the tip side wall-like portion 48a toward the tip side. The extension pin 43 is formed at the central portion in the circumferential direction and on the radially outer side on the surface on the tip side of the tip side wall-like portion 48a. As shown in FIG. 15(b), the shape of the extension pin 43 viewed from the tip side is a substantially arc shape convex toward the radially outer side. Each of the outer surface 43a and the inner surface of the extension pin 43 is a curved surface shape convex toward the radially outer side. The claw portion 44 is formed at the tip end portion (the tip in the protruding direction) of the extension pin 43. The claw portion 44 has a shape that bulges radially outward from the outer surface of the extension pin 43. The surface 44a on the base end side of the claw portion 44 is an inclined surface inclined in the first direction from the tip side toward the base end side. According to such a configuration, when the operation receiving portion 45 is operated in a specific operation direction, the locking claw 42 can be smoothly guided toward the base end side and in the first direction along the surface 44a on the base end side. In the case of this embodiment, as an example, the claw portion 44 is formed as a substantially triangular prism that is long in the circumferential direction.

[0046] As shown in FIGS. 15(b) to 16(b) etc., a gap 46a is formed in the tip side wall-like portion 48a. The gap 46a is formed, for example, at the central portion in the circumferential direction in the tip side wall-like portion 48a and on the radially inner side of the formation region of the extension pin 43. The gap 46a penetrates the tip side wall-like portion 48a in the thickness direction. The gap 46a is formed linearly along the radial direction. The width dimension of the gap 46a is substantially constant regardless of the position in the extending direction of the gap 46a. As shown in FIG. 5(a) etc., the restraining thread 250 passes through the gap 46a and is led out from the thread connecting portion 47 side toward the tip side (stent 200 side).

[0047] As shown in FIG. 15(a), the operation receiving part 45 is connected to the base end edge of the main part 41. In the circumferential direction, the dimension of the operation receiving part 45 is larger than that of the main part 41, and the operation receiving part 45 protrudes on one side and the other side in the circumferential direction from the main part 41, respectively. Also, as shown in FIG. 15(a), a base end side wall-like part 48b is formed on the inner surface (the surface on the central axis 350 side in the radial direction) of the tip side portion of the operation receiving part 45. As shown in FIG. 10(b), the base end side wall-like part 48b viewed from the base end side is formed in a substantially fan-shaped manner centered on the central axis 350. Each of the outer peripheral surface and the inner peripheral surface of the base end side wall-like part 48b has a curved surface shape convex toward the outside in the radial direction. The base end surface of the base end side wall-like part 48b is formed flat and is orthogonal to the central axis 350. On the other hand, the tip end surface of the base end side wall-like part 48b is a stepped surface.

[0048] As shown in FIGS. 12(a), 12(b), 12(c), etc., in the state where the detachable part 40 is attached to the main body part 30, as described above, the locking claw 42 of the detachable part 40 is locked to the corresponding locked part 32. More specifically, the extension pin 43 of the locking claw 42 is inserted into the corresponding opening 35. The extension pin 43 is located at the central part in the circumferential direction and on the outside in the radial direction within the opening 35. The outer surface of the extension pin 43 is in surface contact with a part of the inner peripheral surface of the opening 35 (more specifically, a guide surface 34 described later). The inner surface and both side surfaces (the surfaces at both end sides in the circumferential direction) of the extension pin 43 are separated from the inner peripheral surface of the opening 35, respectively. The claw part 44 and the formation region of the claw part 44 in the extension pin 43 protrude from the tip side of the opening 35.

[0049] As shown in Figures 12(a), 12(b), and 12(c), the detachable portion 40 is positioned in the gap between the inner surface of the peripheral wall portion 38 and the outer surface of the first cylindrical portion 36. The inner surface of the tip side wall portion 48a is positioned along the outer surface of the first cylindrical portion 36. Similarly, the inner surface of the base side wall portion 48b is positioned along the outer surface of the first cylindrical portion 36. Furthermore, as shown in Figures 12(b) and 12(c), a gap is formed in the radial direction between the outer surface of the tip portion of the detachable portion 40 (more specifically, the outer surfaces of the main portion 41 and the tip side wall portion 48a) and the inner surface of the peripheral wall portion 38. As a result, the detachable portion 40 can swing between the inner surface of the peripheral wall portion 38 and the outer surface of the first cylindrical portion 36. Similarly, as shown in Figure 20, a gap is formed between the two sides of the detachable portion 40 (one side and the other side in the circumferential direction) and the partition wall portion 39 in the circumferential direction. This allows the detachable portion 40 to move between adjacent partition wall portions 39 in the circumferential direction.

[0050] In this embodiment, the second direction, i.e., the direction in which the detachable portion 40 is pulled out, is the direction toward the base end of the central axis 350. When the detachable portion 40 is pulled in the second direction while the engagement of the locking claw 42 with the locked portion 32 is maintained, the boundary between the base end surface 44a of the claw portion 44 and the outer surface 43a of the extension pin 43 comes into contact with the tip end surface of the disc portion 31 (more specifically, the locked surface 33, which will be described later), and the detachable portion 40 is prevented from being pulled out of the main body portion 30. On the other hand, when the engagement of the locking claw 42 with the locked portion 32 is released, and the detachable portion 40 is pulled in the second direction, the detachable portion 40 is guided toward the base end along the first cylindrical portion 36 and detaches from the main body portion 30.

[0051] In this invention, the shape of the claw portion 44 is not limited to the above example, and for example, the claw portion 44 may be formed in the shape of a plate that stands upright in the third direction. In this case, the removal of the detachable portion 40 from the main body portion 30 is restricted by surface contact between the base end surface 44a of the claw portion 44 and the locked surface 33.

[0052] The main body 30 is made of, for example, a rigid resin material. This resin material is not particularly limited, but examples include polyethylene, polyolefins such as polypropylene, polyamide, polycarbonate, polystyrene, etc. Similarly, each detachable part 40 is made of, for example, a rigid resin material. This resin material is not particularly limited, but examples include polyethylene, polyolefins such as polypropylene, polyamide, polycarbonate, polystyrene, etc.

[0053] In this embodiment, the locking portion 32 has a guide surface 34 (see Figures 11(b), 13(a), 17(b), 18, etc.) that restricts the movement of the extension pin 43 in the third direction, which is the opposite direction to the first direction, and guides the extension pin 43 in the opposite direction to the intersecting direction, and a locking surface 33 into which the claw portion 44 engages. As shown in Figures 13(a) and 17(b), the locking surface 33 and the guide surface 34 are connected to and intersect each other via the edge 34a that forms their boundary. As shown in Figure 18, the guide surface 34 is curved in a direction that deepens the engagement between the claw portion 44 and the locking surface 33 when the operating receiving portion 45 is operated in a direction perpendicular to the first plane 310, which is a plane including the first and second directions (for example, the direction of arrow D shown in Figure 4(b), etc., and may hereinafter simply be referred to as the "orthogonal direction").

[0054] The third direction referred to here is the direction opposite to the first direction with respect to the guide surface 34. That is, the first direction is the direction opposite to the third direction with respect to the guide surface 34. Furthermore, the state in which the claw portion 44 and the locked surface 33 are engaged means that, when viewed in the second direction (i.e., the direction in which the detachable portion 40 is pulled out), at least a portion of the claw portion 44 and the locked surface 33 overlap each other (see Figures 18 and 19(b)). Furthermore, the state in which the engagement between the claw portion 44 and the locked surface 33 is released means that, when viewed in the second direction (i.e., the direction in which the detachable portion 40 is pulled out), there is no overlap between the claw portion 44 and the locked surface 33 (see Figure 19(a)). Furthermore, in this embodiment, the direction in which the engagement between the claw portion 44 and the locked surface 33 deepens is the direction in which the maximum dimension of the overlapping portion between the claw portion 44 and the locked surface 33 (dimension D1 shown in Figures 18 and 19(b)) increases in the third direction.

[0055] With this configuration, even if the operating receiving portion 45 is operated in a direction different from a specific operating direction, the engagement state of the claw portion 44 with the locking surface 33 can be maintained more reliably.

[0056] Furthermore, in this embodiment, the first direction is the radially inward direction of the main body portion 30, and the third direction is the radially outward direction of the main body portion 30. As shown in Figure 13(a), the claw portion 44 of the locking claw 42 of each detachable portion 40 protrudes toward the third direction from the tip of the extension pin 43 of the locking claw 42 in the extension direction. As shown in Figure 18, the guide surface 34 of each locked portion 32 is formed in a convex arc shape toward the third direction. More specifically, in a direction perpendicular to the first plane 310, the guide surface 34 is gradually displaced toward the first direction from the central part (the apex of the arc) toward one end (one end of the guide surface 34 in the circumferential direction), and is also gradually displaced toward the first direction from the central part (same as above) toward the other end (the other end of the guide surface 34 in the circumferential direction).

[0057] With this configuration, even if the locking claw 42 moves in a first direction (radially inward) relative to the main body 30 when the operating receiving portion 45 is unintentionally operated in a direction different from the specific operating direction, the locking claw 42 slides relative to the locked portion 32 in the opposite direction to the orthogonal direction (for example, in the direction of arrow E shown in Figure 19(b)), thereby canceling out the movement in the first direction relative to the main body 30, and making it easier to maintain the engagement of the claw portion 44 with the locked surface 33 (the overlap between the claw portion 44 and the locked surface 33 in the third direction when viewed in the second direction) (see Figure 19(b)). In contrast, if the guide surface 34 is, for example, a flat surface parallel to the orthogonal direction (for example, the dashed line 410 shown in Figure 19(b)), even if the locking claw 42 that has moved in the first direction slides against the locked surface 33 in the opposite direction to the orthogonal direction, the movement of the locking claw 42 in the first direction relative to the main body 30 is not canceled out. As the locking claw 42 moves in the first direction (radially inward), the engagement of the locking claw 42 with the locked portion 32 is released. In other words, it becomes difficult to sufficiently maintain the overlap between the claw portion 44 and the locked surface 33 in the third direction when viewed in the second direction. Therefore, by forming the guide surface 34 in a convex arc shape toward the third direction, the engagement of the claw portion 44 with the locked surface 33 is more easily maintained.

[0058] In this invention, even if the operating receiver 45 is operated in a direction other than the direction perpendicular to the first plane 310 (orthogonal direction) among the directions intersecting the first plane 310, the locking claw 42 slides against the locked portion 32 in the opposite direction to the orthogonal direction, making it easier to maintain the engagement of the claw portion 44 with the locked surface 33. However, the closer the operating direction of the operating receiver 45 is to the orthogonal direction, the greater the amount of movement of the locking claw 42 in the opposite direction to the orthogonal direction, and the greater the depth of engagement of the claw portion 44 with the locked surface 33. Also, in Figure 19(b), the amount of movement of the locking claw 42 in the opposite direction to the orthogonal direction is exaggerated in the illustration to make the depth of engagement of the claw portion 44 with the locked surface 33 easier to understand.

[0059] In this embodiment, the first and third directions corresponding to each of the multiple attachment / detachment parts 40 are different from each other. More specifically, as described above, the multiple attachment / detachment parts 40 are distributed around the central axis 350 of the main body part 30. As shown in Figure 11(a), the first plane 310a corresponding to the first attachment / detachment part 40a is a plane that includes the center line of the first attachment / detachment part 40a. Similarly, the first plane 310b corresponding to the second attachment / detachment part 40b is a plane that includes the center line of the second attachment / detachment part 40b, and the first plane 310c corresponding to the third attachment / detachment part 40c is a plane that includes the center line of the third attachment / detachment part 40c. In the first attachment / detachment part 40a, the first direction is a direction included in the first plane 310a and radially inward, and the third direction is a direction included in the first plane 310a and radially outward. Similarly, in the second attachment / detachment portion 40b, the first direction is a direction included in the first plane 310b and radially inward, and the third direction is a direction included in the first plane 310b and radially outward. In the third attachment / detachment portion 40c, the first direction is a direction included in the first plane 310c and radially inward, and the third direction is a direction included in the first plane 310c and radially outward.

[0060] In this embodiment, the guide surface 34 is a part of the inner circumferential surface of the opening 35 through which the extension pin 43 is inserted, and the locking surface 33 is a part of the tip-side surface (the tip-side surface of the disc portion 31) of the peripheral edge of the opening 35. The edge 34a is, for example, a part of the opening edge on the tip side of the opening 35 (see Figures 11(b), 13(a), 17(b), 18, etc.).

[0061] More specifically, when viewed from the tip side, the opening 35 is formed in a long, approximately elliptical shape in the circumferential direction and has a convex arc shape towards the radially outward direction. The guide surface 34 is composed of the radially outward portion of the inner circumferential surface of the opening 35. Similarly, the edge 34a is composed of the radially outward portion of the opening edge on the tip side of the opening 35. The locking surface 33 is composed of the radially outward portion of the tip side surface of the peripheral edge of the opening 35. The locking surface 33 is a flat surface perpendicular to the central axis 350 (and thus the second direction). When viewed in the direction of the central axis 350, the apex of the curvature of the guide surface 34 is located on the third direction side. Similarly, when viewed in the direction of the central axis 350, the apex of the arc of the edge 34a is located on the third direction side.

[0062] Before any operation is performed on the operating receiver 45, as shown in Figure 18, the locking claw 42 is positioned at a location corresponding to the apex of the curvature of the guide surface 34 and the apex of the arc of the edge 34a. From this state, when the operating receiver 45 is operated in a direction intersecting the first plane 310, the locking claw 42 slides against the locked portion 32 in a direction opposite to the direction perpendicular to the first plane 310 while maintaining its inserted state in the opening 35. More specifically, when the operating receiver 45 is operated to one side with respect to the first plane 310 in a direction perpendicular to the first plane 310, the extension pin 43 of the locking claw 42 is guided by the guide surface 34 to the other side with respect to the first plane 310. On the other hand, when the operating receiver 45 is operated in a direction perpendicular to the first plane 310, with respect to the first plane 310, the extension pin 43 of the locking claw 42 is guided by the guide surface 34 to the other side with respect to the first plane 310.

[0063] Here, it is preferable that the radius of curvature of the guide surface 34 in the circumferential direction of the main body 30 is smaller than the radius of curvature of the third-direction side surface (in this embodiment, the outer surface 43a) of the extension pin 43. The third-direction side surface of the extension pin 43 referred to here is the surface guided by the guide surface 34. With this configuration, when the operating receiving portion 45 is operated in a direction that includes the second-direction component and the intersecting direction component, and the extension pin 43 is guided by the guide surface 34 in the opposite direction to the orthogonal direction, a sufficient engagement depth (dimension D1) of the claw portion 44 with the locking surface 33 can be ensured. However, the present invention is not limited to this example, and the radius of curvature of the guide surface 34 may be equal to or greater than the radius of curvature of the third-direction side surface 43a of the extension pin 43.

[0064] Furthermore, in the circumferential direction of the main body 30, it is preferable that the radius of curvature of the guide surface 34 is smaller than the radius of curvature of the edge 44b on the third direction side of the claw portion 44. Even with this configuration, when the operating receiving portion 45 is operated in a direction that includes the component in the second direction and the component in the intersecting direction, and the extension pin 43 is guided by the guide surface 34 in the opposite direction to the orthogonal direction, the depth of engagement (dimension D1) of the claw portion 44 with respect to the locking surface 33 can be sufficiently secured. However, the present invention is not limited to this example, and the radius of curvature of the guide surface 34 may be equal to or larger than the radius of curvature of the edge 44b on the third direction side of the claw portion 44.

[0065] In the circumferential direction of the main body 30, it is preferable that the radius of curvature of the third-direction side surface (outer surface 43a) of the extension pin 43 is smaller than the radius of curvature of the third-direction side edge 44b of the claw portion 44. With this configuration, the protrusion height of the claw portion 44, i.e., the engagement depth (dimension D1) of the locking claw 42 with respect to the locking portion 32, can be well secured at both ends in the lateral width direction (direction perpendicular to both the protrusion direction and the thickness direction) of the locking claw 42. However, the present invention is not limited to this example, and the radius of curvature of the third-direction side surface (outer surface 43a) of the extension pin 43 may be equal to or greater than the radius of curvature of the third-direction side edge 44b of the claw portion 44.

[0066] Furthermore, in this embodiment, the detachable part 40 has a pivot point 46 that acts as a pivot point for the swing relative to the main body 30 when the locking claw 42 moves in a first direction relative to the locked part 32. With this configuration, when detaching the detachable part 40 from the main body 30, the locking claw 42 can be smoothly moved in a first direction relative to the locked part 32 by swinging the detachable part 40.

[0067] More specifically, as shown in Figure 4(b), the detachable part 40 has pivot points 46 on both sides, one side and the other side, with reference to the position of the locking claws 42, in a direction perpendicular to the first plane 310. With this configuration, when the operating receiver 45 is operated to pull the detachable part 40 out of the main body 30 in the second direction, the detachable part 40 can swing more stably with the pivot points 46 (the locking claws 42 on one side and the locking claws 42 on the other side) as pivot points.

[0068] Furthermore, a gap (in this embodiment, a gap 46a) is formed between the pivot point 46 on one side and the pivot point 46 on the other side through which the restraining thread 250 passes. As shown in Figure 15(a), the thread connecting portion 47 is positioned at the base end side in the direction of the central axis 350 of the main body portion 30, with respect to the gap. With this configuration, interference between the restraining thread 250 and the pivot point 46 (the locking claw 42 on one side and the locking claw 42 on the other side) is suppressed, while it becomes easy to lead the restraining thread 250 out from the attachment / detachment portion 40 (and thus the release operation portion 20) toward the tip side (stent 200 side).

[0069] Furthermore, as shown in Figure 15(a), the locking claw 42 is positioned at the tip end of the direction of the central axis 350 of the main body 30, with respect to the pivot point 46, and the operating receiving part 45 is positioned at the base end of the direction of the central axis 350 of the main body 30, with respect to the pivot point 46. With this configuration, by operating the operating receiving part 45, the detachable part 40 is swung with the pivot point 46 as the pivot point for the swing, and the locking claw 42 can be smoothly moved in the first direction.

[0070] More specifically, as shown in Figures 5(a) and 5(b), by operating the operating receiver 45 in a direction having a component in the third direction (radially outward), the detachable part 40 can be swung in a forward-tilting direction, and the locking claw 42 can be moved in the first direction. This releases the engagement of the locking claw 42 with respect to the locked part 32 (Figure 19(a)). On the other hand, by operating the operating receiver 45 in a direction having a component in the first direction (radially inward), the detachable part 40 can be swung in a backward-tilting direction, and the locking claw 42 can be moved in the third direction. In this embodiment, as described above, the locked part 32 has a guide surface 34 that restricts the movement of the extension pin 43 in the third direction. Therefore, even if the operating receiving portion 45 is operated in a direction having a component in the first direction while the locking claw 42 is engaged with the locked portion 32, the movement of the extending pin 43 in the third direction, and consequently the swinging of the detachable portion 40 in the backward tilting direction, is restricted by the guide surface 34.

[0071] Furthermore, when the operating part 45 is operated on the part located on the second direction side (the point of force application E1 shown in Figure 25), the detachable part 40 can be swung with less force due to the lever principle and the locking claw 42 can be moved in the first direction compared to when the operating part is operated on the part located on the side intersecting the first plane 310 (the point of force application E2 shown in Figure 25). In other words, when the operating part 45 is operated in a specific operating direction, the detachable part 40 can be easily detached from the main body 30, while when the operating part 45 is operated in a direction different from the specific operating direction, the engagement state of the claw 44 with the locking surface 33 can be maintained more reliably.

[0072] More specifically, as shown in Figure 25, when an operation is performed on the part of the operating receiver 45 located on the second direction side (point of force application E1), force is transmitted to the locking claw 42 (point of application L1) via the contact point between one fulcrum 46 and the outer circumferential surface of the first cylindrical part 36 (fulcrum F1) and the contact point between the other fulcrum 46 and the outer circumferential surface of the first cylindrical part 36 (fulcrum F2) (for example, force is transmitted along the imaginary lines 402a and 402b). Also, when an operation is performed on the part of the operating receiver 45 located on the side in the direction intersecting the first plane 310 (point of force application E2), force is transmitted to the locking claw 42 (point of application L1) via the contact point between one fulcrum 46 and the outer circumferential surface of the first cylindrical part 36 (fulcrum F1) (or the contact point between the other fulcrum 46 and the outer circumferential surface of the first cylindrical part 36 (fulcrum F2)) (for example, force is transmitted along the imaginary line 404).

[0073] On the other hand, when an operation is performed on the portion located on the second direction side (point of force application E1), the force vector (the direction of the force from point of force application E1 to point of application L1 (for example, the direction of extension of the imaginary line 401)) passes through a virtual fulcrum located midway between fulcrums F1 and F2 in the circumferential direction (for example, fulcrum F3a) and extends parallel to the central axis 350. At this time, the length from point of force application E1 to fulcrum F3a is maximum on the imaginary line 401, and the length from fulcrum F3a to point of application L1 is minimum. Therefore, when an operation is performed on the portion located on the second direction side, the detachable part 40 can be swung with minimal force by the lever principle, and the locking claw 42 can be moved in the first direction. In contrast, when an operation is performed on the portion located on the side intersecting the first plane 310 (point of force application E2), the force vector (the direction of the force from point of force application E2 to point of application L1 (for example, the direction of extension of the imaginary line 403)) passes through a virtual fulcrum (for example, fulcrum F3b) located on the side of fulcrum F1 (or fulcrum F2) rather than the midpoint between fulcrum F1 and fulcrum F2 in the circumferential direction, and extends at an inclination (intersecting) with respect to the central axis 350. In the imaginary line 403, the further the position of point of force application E2 is from point of force application E1 (the greater the inclination angle of the imaginary line 403 with respect to the central axis 350), the smaller the length from point of force application E2 to fulcrum F3b, while the larger the length from fulcrum F3b to point of application L1. Therefore, the further the position of the part of the operating receiver 45 from the second direction (the closer it is to the direction perpendicular to the first plane 310), the less efficient the force is when swinging the detachable part 40. For this reason, when the operation is performed on the part located on the second direction side, the detachable part 40 can be swung and the locking claw 42 can be moved in the first direction with less force due to the lever principle compared to when the operation is performed on the part located on the side perpendicular to the first plane 310.

[0074] Note that the positions of the point of force application, fulcrum, and point of application shown in Figure 25 are examples only and will change depending on the position of the contact point between the fulcrum 46 and the outer surface of the first cylindrical part 36, the position of the part of the operating receiving part 45 where the operation is performed, etc.

[0075] In this embodiment, as shown in Figure 15(b), in the tip side wall portion 48a, with respect to the gap 46a, the portion on one side in the circumferential direction constitutes one side pivot portion 46, and the portion on the other side in the circumferential direction constitutes the other side pivot portion 46. The inner circumferential surfaces of the one side pivot portion 46 and the other side pivot portion 46 are arranged along the outer circumferential surface of the first cylindrical portion 36. When an operation is performed on the operating receiving portion 45 in a direction having a third direction (or first direction) component, the detachable portion 40 swings in a forward tilting direction (or backward tilting direction) with the contact point between the pivot portion 46 and the outer circumferential surface of the first cylindrical portion 36 as the pivot point. The contact of the pivot portion 46 with the outer circumferential surface of the first cylindrical portion 36 may be point contact, line contact, or surface contact.

[0076] Here, as shown in Figure 13(b), the corners at the tip of each of the pivot points 46 (one pivot point 46 and the other pivot point 46) have a rounded R-chamfer shape. With this configuration, the detachable part 40 can swing smoothly in a forward-tilting direction with the pivot point 46 as the pivot point. Therefore, when the operating receiving part 45 is operated in a direction having a third-direction component, the locking claw 42 can be moved smoothly in the first direction.

[0077] The dimensions of the locking claw 42 in the radial direction are preferably smaller than, for example, the dimensions of the locking claw 42 in the circumferential direction. Similarly, the dimensions of the extension pin 43 in the radial direction are preferably smaller than, for example, the dimensions of the extension pin 43 in the circumferential direction. With this configuration, the dimensions of the locking claw 42 in the radial direction can be suppressed while the extension pin 43 can be sufficiently curved in an arc shape in the circumferential direction. Therefore, a sufficient depth of engagement of the claw portion 44 with the locking surface 33 can be ensured.

[0078] Furthermore, the operating receiving portion 45 includes, for example, a hole, a recess, or an uneven portion (in this embodiment, a through hole 45a described later) and a surrounding portion 45c that surrounds the hole, recess, or uneven portion (same as above). This allows the operating receiving portion 45 to be easily operated by using the hole, recess, or uneven portion as a finger rest.

[0079] Furthermore, regarding the dimensions of the surrounding portion 45c in a direction perpendicular to the first plane 310, the dimensions of the portion of the contact surrounding portion 45c located on the second direction side of the hole, recess, or uneven portion (dimension L1 shown in Figure 16(a)) are smaller than the dimensions of the portion of the surrounding portion 45c corresponding to the center of the hole, recess, or uneven portion (dimension L2 shown in Figure 16(a)). With this configuration, when operating the operating receiving portion 45 by placing a finger on the hole, recess, or uneven portion, the detachable portion 40 can be easily pulled out in the second direction by natural traction.

[0080] In this embodiment, the operating receiving portion 45 includes, as an example, a through hole 45a that penetrates the operating receiving portion 45 in a first direction, and a surrounding portion 45c that surrounds the through hole 45a. In this embodiment, a concave curved surface 45b that is recessed radially inward is formed on the outer circumferential surface of the operating receiving portion 45. As shown in Figure 16(a), the through hole 45a is formed in the inner region of the concave curved surface 45b and at a position eccentric to the base end with respect to the center of the concave curved surface 45b. With this configuration, when operating the operating receiving portion 45, the user's fingers can fit well against the operating receiving portion 45. However, the present invention is not limited to this example, and the operating receiving portion 45 may have a recess or an uneven portion (uneven surface) instead of a through hole 45a.

[0081] Furthermore, as shown in Figure 10(b), when viewed in the direction of the central axis 350, the multiple attachment / detachment parts 40 are positioned to fit within the envelope 370 of the main body 30. In this embodiment, the envelope 370 is a virtual circle that encloses the main body 30 with the smallest diameter when viewed in the direction of the central axis 350. Also, in Figure 10(b), the envelope 370 is conveniently shown as a dashed line offset radially outward from the outline of the main body 30. With this configuration, when a user grasps the main body 30, it is possible to prevent the user's hand from coming into contact with the multiple attachment / detachment parts 40 and applying external force. Therefore, it is possible to prevent the attachment / detachment parts 40 from unintentionally detaching from the main body 30.

[0082] Furthermore, as shown in Figure 4(a), the detachable portion 40 is formed in a shape that curves radially outward from the main body portion 30 toward the second direction. With this configuration, even if a force radially inward is unintentionally applied to the detachable portion 40 when the user grips the main body portion 30, a force will act on the locking claw 42 to move it toward the third direction (i.e., a force that will cause the detachable portion 40 to swing in a backward tilting direction), thereby preventing the locking claw 42 from unintentionally disengaging from the locked portion 32.

[0083] More specifically, in this embodiment, the operating receiver 45 is formed in a shape that curves radially outward from the main body 30 toward the second direction. This allows that even if a force radially inward is unintentionally applied to the operating receiver 45 when the user grips the main body 30, a force will act on the locking claw 42 to move toward the third direction (a force that will swing the detachable part 40 toward the rearward tilt), thereby preventing the locking claw 42 from unintentionally disengaging from the locked part 32.

[0084] Here, as described above, the release operation unit 20 includes a position shift unit 50 that shifts the position of the attachment / detachment unit 40 relative to the main body unit 30 when the operation receiving unit 45 is operated in an intersecting direction, which is a direction that intersects with the first plane 310, which is a plane that includes the first direction and the second direction. The position shift unit 50 has a main body side contact unit 51 on the main body unit 30 and an attachment / detachment side contact unit 56 on the attachment / detachment unit 40. In this embodiment, the attachment / detachment side contact unit 56 receives a reaction force from the main body side contact unit 51 on both sides, one side and the other side, with reference to the position of the locking claw 42, in a direction perpendicular to the first plane 310. That is, in the attachment / detachment unit 40, there are parts that receive a reaction force from the main body unit 30 on both sides, one side and the other side, with reference to the position of the locking claw 42, in a direction perpendicular to the first plane 310.

[0085] With this configuration, when the operating receiver 45 is operated in an intersecting direction, the entire locking claw 42 can be shifted more evenly and stably in a direction that includes a component in the third direction. Furthermore, in both cases, when the operating receiver 45 is operated on one side of the intersecting direction with respect to the first plane 310, and when the operating receiver 45 is operated on the other side of the intersecting direction with respect to the position of the locking claw 42, the locking claw 42 can be shifted in a direction that includes a component in the third direction.

[0086] More specifically, as shown in Figure 16(a), the detachable contact portion 56 has a first contact portion 57 located on one side with respect to the locking claw 42 in a direction perpendicular to the first plane 310, and a second contact portion 58 located on the other side with respect to the locking claw 42 in a direction perpendicular to the first plane 310. With this configuration, when the operating receiving portion 45 is operated in a crossing direction, the locking claw 42 can be shifted more evenly and stably in a direction that includes a component in the third direction.

[0087] Furthermore, in this embodiment, as shown in Figure 20, at least one of the detachable contact portion 56 and the main body contact portion 51 is a surface whose cross-sectional shape perpendicular to the second direction is convex toward the third direction or the first direction. With this configuration, the detachable portion 40 can be shifted in a direction including the component of the third direction with a sufficient amount of movement. Therefore, the engagement depth of the claw portion 44 with the locked surface 33 can be sufficiently maintained.

[0088] More specifically, the main body contact portion 51 is, for example, a semi-cylindrical curved surface that is convex toward the third direction with the second direction as its central axis. With this configuration, the attachment / detachment portion 40 can be shifted toward the third direction with a sufficient amount of movement. Therefore, the depth of engagement of the claw portion 44 with the locking surface 33 can be sufficiently maintained. Note that the term "semi-cylindrical" here is not limited to a shape in which a cylinder is divided in half along its outer diameter, but also includes shapes in which a cylinder is divided into multiple parts in the circumferential direction.

[0089] As shown in Figures 22(a) to 24(b), in this embodiment, in addition to the main body side contact portion 51, the contact surfaces of the first contact portion 57 and the second contact portion 58 (contact surfaces with respect to the main body side contact portion 51) are also semi-cylindrical curved surfaces with the central axis 350 of the main body portion 30 as the central axis. In Figures 22(a) to 24(b), the main body side contact portion 51 is schematically shown as a simplified semi-cylindrical shape. Similarly, in Figures 22(a) to 24(b), the contact surfaces with the main body side contact portion 51 and their vicinity at each of the first contact portion 57 and the second contact portion 58 (tip side wall-like portion 48a) are schematically shown as simplified semi-cylindrical shapes. Furthermore, in Figures 22(b), 23(b), and 24(b), the amounts of movement of the first contact portion 57 and the second contact portion 58 are exaggerated in the illustration to make it easier to understand the structure in which the detachable contact portion 56 is shifted in a direction that includes a component in the third direction.

[0090] With the detachable part 40 attached to the main body part 30, as shown in Figure 22(a), in a direction perpendicular to the first plane 310, the axes of the first contact part 57 and the second contact part 58 are arranged parallel to the axis of the main body side contact part 51 and are fitted to the main body side contact part 51. Also, in a direction perpendicular to the first plane 310, the first contact part 57 and the second contact part 58 are arranged on one side and the other side, respectively, with respect to the apex (edge) of the main body side contact part 51. When the operating receiver part 45 is operated in a specific operating direction, the first contact part 57 and the second contact part 58 (and thus the detachable part 40) move toward the base end side, guided by the main body side contact part 51, while maintaining their position along the main body side contact part 51 (Figure 21(a)).

[0091] In contrast, when the operating receiver 45 is operated in the intersecting direction (for example, in the direction of arrow D), as shown in Figures 22(b), 23(b), and 24(b), each of the first contact portion 57 and the second contact portion 58 extends in the third direction and rotates in a direction that includes a component in the opposite direction to the intersecting direction (for example, in the direction of arrow E), with the straight line 360 ​​passing through the axis of the main body side contact portion 51 as the axis of rotation. As a result, the axes of each of the first contact portion 57 and the second contact portion 58 intersect with the axis of the main body side contact portion 51. More specifically, from the state shown in Figures 22(a), 23(a), and 24(a), each of the first contact portion 57 and the second contact portion 58 moves along the main body side contact portion 51 in a direction that approaches the apex (edge) of the main body side contact portion 51. In this case, as described above, since a portion of each of the first contact portion 57 and the second contact portion 58 is a semi-cylindrical curved surface, it lifts up in a third direction from the main body side contact portion 51, as shown in Figure 23(b). In this way, each of the first contact portion 57 and the second contact portion 58, and consequently the locking claw 42, receives a reaction force from the main body side contact portion 51 and is shifted in a direction that includes a component in the third direction (Figure 21(b)). Note that in Figures 21(a) and 21(b), the locking claw 42 is shown with a dashed line.

[0092] Furthermore, in this embodiment, the radius of curvature of the main body side contact portion 51 is, for example, equivalent to the radius of curvature of the first contact portion 57 and the second contact portion 58. With this configuration, a sufficient contact area of ​​the detachable side contact portion 56 with respect to the main body side contact portion 51 can be secured, and the first contact portion 57 and the second contact portion 58 can be fitted well with respect to the main body side contact portion 51. As a result, the force required to operate the operating receiving portion 45 in a cross direction is greater than the force required to operate the operating receiving portion 45 in a specific operating direction. This makes it easier to pull the detachable portion 40 out in the second direction with natural traction when detaching it from the main body portion 30.

[0093] In the present invention, the shape of the main body contact portion 51 is not limited to the above example. For example, it may be a rectangular cylindrical shape with the central axis 350 of the main body portion 30 as its central axis and convex toward the third direction. Even with such a configuration, when the operating receiver portion 45 is operated in the intersecting direction, each of the first contact portion 57 and the second contact portion 58 moves along the main body contact portion 51 in a direction approaching the apex (or top surface) of the main body contact portion 51, thereby receiving a reaction force from the main body contact portion 51 and being shifted in a direction including a component of the third direction. Similarly, in the present invention, the shape of each of the first contact portion 57 and the second contact portion 58 is not limited to the above example. For example, it may be a flat surface. Even with such a configuration, when the operating receiver portion 45 is operated in the intersecting direction, each of the first contact portion 57 and the second contact portion 58 moves along the main body contact portion 51 in a direction approaching the apex of the main body contact portion 51, thereby receiving a reaction force from the main body contact portion 51 and being shifted in a direction including a component of the third direction. Furthermore, each of the main body side contact portion 51 and the detachable side contact portion 56 may be, for example, a surface whose cross-sectional shape perpendicular to the second direction is convex toward the first direction. In this case, when the operating receiving portion 45 is operated in the intersecting direction, each of the first contact portion 57 and the second contact portion 58 moves along the main body side contact portion 51 in a direction away from the apex of the convexity of the main body side contact portion 51, thereby receiving a reaction force from the main body side contact portion 51 and being shifted in a direction that includes a component of the third direction.

[0094] Furthermore, a gap (in this embodiment, a gap 46a) is formed between the first contact portion 57 and the second contact portion 58 through which the restraining thread 250 passes, and the thread connecting portion 47 is positioned on the second direction side with respect to this gap. With this configuration, interference between the restraining thread 250 and the first contact portion 57 and the second contact portion 58 is suppressed, while it becomes easy to lead the restraining thread 250 out from the attachment / detachment portion 40 (and consequently the release operation portion 20) toward the tip side (stent 200 side).

[0095] As shown in Figure 16(a), the locking claw 42 is positioned on the opposite side from the second direction with respect to the detachment side contact portion 56, and the operating receiving portion 45 is positioned on the second direction side with respect to the detachment side contact portion 56. In other words, the locking claw 42 is positioned on the tip side of the detachment side contact portion 56, and the operating receiving portion 45 is positioned on the base side of the detachment side contact portion 56. With this configuration, by operating the operating receiving portion 45, the detachment portion 40 can be swung with the detachment side contact portion 56 as the pivot point, and the locking claw 42 can be moved in the first direction.

[0096] As shown in Figures 18 and 19(b), when the operating receiver 45 is operated in the intersecting direction, the locking claw 42 is allowed to move in the opposite direction relative to the main body 30 while maintaining its engagement with the locked surface 33. More specifically, as described above, the opening 35 into which the locking claw 42 is locked has an elongated elliptical shape in the circumferential direction. Therefore, when the operating receiver 45 is operated in the intersecting direction, the locking claw 42 can move within the opening 35 in the opposite direction relative to the intersecting direction while maintaining its engagement with the locked surface 33. With this configuration, when the operating receiver 45 is operated in the intersecting direction, the first contact portion 57 and the second contact portion 58 can each move (rotate) in a direction approaching the apex of the main body side contact portion 51 with a sufficient amount of movement while maintaining the engagement of the locking claw 42 with the locked surface 33.

[0097] In this embodiment, as shown in Figure 15(b), in the tip side wall portion 48a, with respect to the gap 46a, the portion on one side in the circumferential direction constitutes the first contact portion 57, and the portion on the other side in the circumferential direction constitutes the second contact portion 58. That is, in the tip side wall portion 48a, with respect to the gap 46a, the portion on one side in the circumferential direction constitutes the aforementioned one-side pivot portion 46 and the first contact portion 57, and the portion on the other side in the circumferential direction constitutes the aforementioned other-side pivot portion 46 and the second contact portion 58. Furthermore, in the first cylindrical portion 36, the portion between adjacent partition wall portions 39 in the circumferential direction constitutes the main body side contact portion 51. More specifically, the first cylindrical portion 36 is divided into three equal parts by three partition walls 39, and these three divided portions constitute the main body side contact portion 51 corresponding to the first detachable portion 40a, the main body side contact portion 51 corresponding to the second detachable portion 40b, and the main body side contact portion 51 corresponding to the third detachable portion 40c, respectively. As shown in Figure 21(b), when the operating receiver 45 is operated in the intersecting direction, a part of the inner circumferential surface of the tip side wall portion 48a of the detachable portion 40 (the respective contact surfaces of the first contact portion 57 and the second contact portion 58) (more specifically, the portion on the locking claw 42 side) lifts up in a third direction from the first cylindrical portion 36 (main body side contact portion 51). As a result, the detachable side contact portion 56 and thus the locking claw 42 are shifted in a third direction.

[0098] The following describes an example of how to use the stent delivery device 100 of this embodiment. In the following example, we will describe an example in which the stent delivery device 100 is used in a procedure to place a stent 200 inside the large intestine (not shown). The explanation will begin from a state in which the tip of the insertion part of the endoscope (not shown) has been inserted into the large intestine (not shown) from the anal side of the living body, a needle hole has been formed inside the large intestine, and the tip of the guidewire (not shown) is anchored (locked) to the needle hole.

[0099] First, the stent delivery device 100 is introduced along the guide wire. More specifically, the inner sheath 60 is fitted onto the guide wire, and the inner sheath 60 and outer sheath 10 are fed to the needle hole by sliding the inner sheath 60 from the proximal end to the proximal end along the axial direction of the guide wire. Next, while gripping the release operation unit 20 with one hand, the handle 80 is moved backward towards the release operation unit 20 together with the outer sheath 10 with the other hand, thereby exposing the entire stent 200 from the outer sheath 10 (see Figure 1). In this state, the restraint thread 250 is pulled out towards the proximal end by operating the release operation unit 20, thereby releasing the stent 200 from the restraint state imposed by the restraint thread 250.

[0100] More specifically, as shown in Figures 6(a) and 6(b), the first detachable part 40a is detached from the main body 30, thereby pulling out the first restraining thread 250a towards the proximal end and releasing the proximal end 230 (the part on the anal side of the living body) of the stent 200 from the restraint caused by the first restraining thread 250a. Next, as shown in Figures 7(a) and 7(b), the second detachable part 40b is detached from the main body 30, thereby pulling out the second restraining thread 250b towards the proximal end and releasing the tip 210 (the part on the oral side of the living body) of the stent 200 from the restraint caused by the second restraining thread 250b. Finally, as shown in Figures 8(a) and 8(b), the third detachable part 40c is detached from the main body 30, thereby pulling out the third restraining thread 250c towards the proximal end and releasing the middle part 220 of the stent 200 from the restraint caused by the third restraining thread 250c. In this way, different sections of the stent 200 in the axial direction can be individually deformed from a reduced diameter state to an expanded state at desired timings, allowing the stent 200 to be placed at a desired location in the large intestine.

[0101] Here, when detaching the detachable part 40 from the main body 30, the operating receiver 45 is operated in a specific operating direction. More specifically, as shown in Figures 5(a) and 5(b), by operating the operating receiver 45 in a direction that includes a component on the base end side (second direction) and a component on the radially outward side (third direction) within the first plane 310, the detachable part 40 can be swung in a forward tilting direction, moving the locking claw 42 radially inward (first direction) while the detachable part 40 can be pulled out towards the base end. As a result, the engagement of the locking claw 42 with the locked part 32 is released (Figure 19(a)), and the detachable part 40 is detached from the main body 30. The detachable part 40, which has been detached from the main body 30 in this way, is then pulled further towards the base end (or in a direction including the base end component) with a sufficient amount of traction (for example, an amount of traction that is sufficient to completely release the restraining thread 250 from the stent 200). This allows the stent 200 to be released from the restraint state imposed by the restraint thread 250.

[0102] On the other hand, as described above, when the operating receiving portion 45 is operated in a direction that includes a component in the second direction and a component in the intersecting direction which intersects the first plane 310, which is a plane that includes the first and second directions, the locking claw 42 slides against the locked surface 33 in the opposite direction to the intersecting direction while maintaining its engagement with the locked surface 33 (see Figures 18 and 19(b)). With this configuration, even if the detachable portion 40 swings in a forward-tilting direction and the locking claw 42 moves in the first direction when operated in a direction different from a specific operating direction, the engagement of the locking claw 42 with the locked portion 32 is maintained (or is easily maintained) (see Figure 19(b)).

[0103] Furthermore, as described above, when the operating receiving portion 45 is operated in an intersecting direction, which is a direction that intersects the first plane 310, which is a plane that includes the first and second directions, the detachment-side contact portion 56 receives a reaction force from the main body-side contact portion 51, causing the position of the detachment portion 40 relative to the main body portion 30 to shift in a direction that includes a component of the third direction (see Figures 21(b), 22(a) to 24(b)). With this configuration, when the direction of operation to the operating receiving portion 45 is an intersecting direction (i.e., a direction different from a specific operating direction), even if the detachment portion 40 swings in a forward-tilting direction and the locking claw 42 moves in the first direction (radially inward), the detachment portion 40 and, consequently, the locking claw 42 are shifted in a direction that includes a component of the third direction, thus canceling out the movement of the locking claw 42 in the first direction. Therefore, it becomes easier to maintain the engagement of the locking claw 42 with the locked portion 32.

[0104] Furthermore, in this embodiment, if the direction of operation to the operating receiver 45 is in an intersecting direction, even if the detachment unit 40 swings in a forward-tilting direction and the locking claw 42 moves in the first direction, the locking claw 42 slides against the locked portion 32 in the opposite direction to the intersecting direction and is shifted by the position shift unit 50 in a direction that includes a component in the third direction. With this configuration, it is easier to more reliably counteract the movement of the locking claw 42 in the first direction and maintain the engagement of the locking claw 42 with the locked portion 32. More specifically, when the operating receiver 45 is operated in a direction that includes a component in the intersecting direction, the detachment unit 40 rotates in a direction that includes a component in the opposite direction to the intersecting direction, with a virtual straight line (for example, a virtual straight line corresponding to a straight line 360) that extends in the third direction and passes through the center of the detachment unit 40 as the axis of rotation. As a result, the locking claw 42 is guided by the guide surface 34 and slides against the locked surface 33 in the opposite direction to the intersecting direction. Furthermore, each of the first contact portion 57 and the second contact portion 58 moves along the main body side contact portion 51 in a direction approaching the apex (ridge) of the main body side contact portion 51, and is shifted in a direction that includes a component in the third direction by receiving a reaction force from the main body side contact portion 51. As a result, even if the detachable portion 40 swings in a forward-tilting direction and the locking claw 42 moves in the first direction, this movement of the locking claw 42 in the first direction is offset, making it easier to maintain the engagement of the locking claw 42 with the locked portion 32.

[0105] The present invention is not limited to the embodiments described above, and includes various modifications, improvements, and other forms as long as the objectives of the present invention are achieved.

[0106] For example, in the present invention, the number of detachable parts 40 and restraint threads 250 is not limited to the above example, and can be appropriately set according to the dimensions and application of the stent 200. In other words, the number of detachable parts 40 and restraint threads 250 may be two or less, or four or more. Also, the number of detachable parts 40 and the number of restraint threads 250 may be different from each other.

[0107] Furthermore, in the present invention, the first, second, and third directions are not limited to the examples described above and can be set as appropriate. More specifically, for example, the first direction may be one side in the axial direction of the main body 30, the third direction may be the other side in the axial direction of the main body 30, and the second direction may be the radially outer side of the main body 30. That is, the detachable part 40 may be mounted on the main body 30 in a direction perpendicular to the central axis 350 of the main body 30.

[0108] This embodiment encompasses the following technical concept: (1) A delivery device capable of transporting a stent, comprising: a long sheath that holds the stent, which is constrained in a reduced diameter state by a restraining thread, at its tip; a release operation unit provided at the base end of the sheath for pulling the restraining thread towards the base end to release the stent from the restrained state by the restraining thread; the release operation unit comprises: a main body; a detachable part detachably provided to the main body and used with the base end portion of the restraining thread connected; the detachable part comprises: a locking claw that is locked to the main body; and an operation receiving part that receives operation by a user; the main body has a locked portion to which the locking claw is locked; the engagement of the locking claw with respect to the locked portion is released when the locking claw moves in a first direction relative to the locked portion; A stent delivery device wherein, when the engagement of the locking claw with the locked portion is released, the detachable portion is pulled out in a second direction intersecting the first direction, thereby detaching the detachable portion from the main body, and when the operating receiving portion is operated in a direction including the second direction component and the intersecting direction component which is a direction intersecting the first plane which is a plane including the first and second directions, the locking claw slides against the locked portion in the opposite direction to the intersecting direction while maintaining its engagement with the locked portion.(2) The locking claw comprises an extension pin extending from the operating receiving portion side in a direction having a directional component opposite to the second direction, and a claw portion provided at the tip of the extension pin in the extension direction and engaging with the locked portion, wherein the locked portion comprises a guide surface that restricts the movement of the extension pin in a third direction which is opposite to the first direction and guides the extension pin in a direction opposite to the intersecting direction, and a locked surface with which the claw portion engages, wherein the locked surface and the guide surface are connected to and intersect each other via an edge forming their boundary, and the guide surface is curved in a direction in which the engagement between the claw portion and the locked surface deepens when the operating receiving portion is operated in a direction perpendicular to a first plane which is a plane including the first direction and the second direction. (2-1) The stent delivery device according to (1), wherein the first direction is radially inward of the main body and the third direction is radially outward of the main body. (2-2) The stent delivery device according to (1), wherein the first direction is one side in the axial direction of the main body and the third direction is the other side in the axial direction of the main body. (2-3) The stent delivery device according to any one of (2) to (2-2), wherein the main body portion has an opening, the extension pin is inserted through the opening, the claw portion protrudes from the opening to one side in the axial direction of the opening, the opening and a part of the peripheral edge of the opening on the main body portion constitute the locking portion, the guide surface is made up of the portion on the third direction side of the inner circumferential surface of the opening, the edge is made up of the portion on the third direction side of the opening edge on one side of the opening, and the locking surface is made up of the portion on the third direction side of the surface on one side of the peripheral edge of the opening.(3) The stent delivery device according to (2) or (2-3), wherein the release operation unit has a plurality of attachment / detachment units distributed around the central axis of the main body and a plurality of locking units corresponding to each attachment / detachment unit, the first direction is radially inward of the main body and the third direction is radially outward of the main body, the claw portion of the locking claw of each attachment / detachment unit protrudes toward the third direction from the tip in the extension direction of the extension pin of the locking claw and the guide surface of each locking unit is formed in a convex arc toward the third direction. (3-1) The stent delivery device according to (3), wherein in a direction perpendicular to the first plane, the guide surface is gradually displaced toward the first direction from the center of the guide surface toward one side and gradually displaced toward the first direction from the center of the guide surface toward the other side. (4) The stent delivery device according to (3), wherein the radius of curvature of the guide surface in the circumferential direction of the main body is smaller than the radius of curvature of the third direction side surface of the extension pin. (5) The stent delivery device according to any one of (1) to (4), wherein the radius of curvature of the guide surface in the circumferential direction of the main body is smaller than the radius of curvature of the third direction side edge of the claw portion. (6) The stent delivery device according to any one of (1) to (5), wherein the radius of curvature of the third direction side surface of the extension pin in the circumferential direction of the main body is smaller than the radius of curvature of the third direction side edge of the claw portion. (7) The stent delivery device according to any one of (1) to (6), wherein the detachable portion has a pivot point that serves as a pivot point for the swing relative to the main body when the locking claw moves in the first direction relative to the locked portion. (8) The stent delivery device according to (7), wherein the detachable portion has the pivot points on both sides, one side and the other side, with reference to the position of the locking claw, in a direction perpendicular to the first plane. (9) The stent delivery device according to (8), wherein the detachable portion has a thread connecting portion to which the restraining thread is connected, a gap is formed between the pivot point on the one side and the pivot point on the other side through which the restraining thread passes, and the thread connecting portion is positioned at the base end side in the direction of the central axis of the main body with reference to the gap.(10) The stent delivery device according to any one of (7) to (9), wherein the locking claw is positioned at the tip end in the direction of the central axis of the main body with respect to the pivot point, and the operating receiving portion is positioned at the base end in the direction of the central axis of the main body with respect to the pivot point. (11) The stent delivery device according to any one of (1) to (10), wherein the operating receiving portion has a hole, a recess, or an uneven portion and a surrounding portion surrounding the hole, recess, or uneven portion, and the dimensions of the surrounding portion in a direction perpendicular to the first plane such that the dimensions of the portion of the surrounding portion located on the second direction side of the hole, recess, or uneven portion are smaller than the dimensions of the portion of the surrounding portion corresponding to the center of the hole, recess, or uneven portion. (12) The stent delivery device according to any one of (1) to (11), wherein, when viewed in the direction of the central axis, the plurality of attachment / detachment parts are positioned to fit within the envelope of the main body. (13) The stent delivery device according to any one of (1) to (12), wherein the attachment / detachment parts are formed in a shape that curves outward radially from the main body toward the second direction.

[0109] Furthermore, as described above, the stent delivery device 100 does not necessarily have to be configured such that, when the operating receiving portion 45 is operated in a direction including a component in the second direction and a component in the intersecting direction, the locking claw 42 slides relative to the locked portion 32 in the opposite direction to the intersecting direction while maintaining its engagement with the locked portion 32. In other words, the present invention also encompasses the following technical concepts (i) to (xi).

[0110] (i) A stent delivery device for transporting a stent, comprising: a long sheath that holds the stent, which is constrained in a reduced diameter state by a restraining thread, at its distal end; a release operation unit provided at the base end of the sheath for pulling the restraining thread towards the base end to release the stent from the restrained state by the restraining thread, wherein the release operation unit comprises: a main body; and a detachable part detachably provided to the main body and used with the base end portion of the restraining thread connected to it, wherein the detachable part comprises: a locking claw that is locked to the main body; and an operation receiving part that receives operation by a user, wherein the main body has a locked portion to which the locking claw is locked, and the engagement of the locking claw with respect to the locked portion is released when the locking claw moves in a first direction relative to the locked portion, A stent delivery device wherein, with the engagement of the locking claw with respect to the locked portion released, the detachable portion is pulled out in a second direction intersecting the first direction, thereby detaching the detachable portion from the main body, the release operation portion includes a position shifting portion that shifts the position of the detachable portion relative to the main body when the operation receiving portion is operated in an intersecting direction which is a direction intersecting the first plane which is a plane including the first direction and the second direction, the position shifting portion has a main body side contact portion of the main body and a detachable side contact portion of the detachable portion, the detachable side contact portion receives a reaction force from the main body side contact portion to shift the position of the detachable portion relative to the main body, and the direction in which the position shifting portion shifts the detachable portion includes a component of a third direction which is the opposite direction to the first direction. (i-i) The stent delivery device according to (i), wherein the first direction is the radially inward side of the main body, and the third direction is the radially outward side of the main body. (i-ii) The stent delivery device according to any one of (i), wherein the first direction is one side in the axial direction of the main body, and the third direction is the other side in the axial direction of the main body.(ii) The stent delivery device according to any one of (i) to (i-ii), wherein the detachable side contact portion receives a reaction force from the main body side contact portion on both sides, one side and the other side, with reference to the position of the locking claw, in a direction perpendicular to the first plane. (iii-i) The stent delivery device according to (i), wherein the detachable side contact portion receives a reaction force from the main body side contact portion on one side, with reference to the position of the locking claw, in a direction perpendicular to the first plane. (iii) The stent delivery device according to (ii), wherein at least one of the detachable side contact portion and the main body side contact portion is a surface whose cross-sectional shape perpendicular to the second direction is convex toward the third direction or the first direction. (iv) The stent delivery device according to (iii), wherein the main body side contact portion is a semi-cylindrical curved surface that is convex toward the third direction with the second direction as its central axis. (v) The stent delivery device according to any one of (i) to (iv), wherein the detachable contact portion comprises a first contact portion located on one side with respect to the locking claw in a direction perpendicular to the first plane, and a second contact portion located on the other side with respect to the locking claw in a direction perpendicular to the first plane. (v-i) The stent delivery device according to (v), wherein in a direction perpendicular to the first plane, the first contact portion and the second contact portion are located on one side and the other side, respectively, with respect to the apex of the main body contact portion. (v-ii) The stent delivery device according to (v) or (v-i), wherein the contact surface of each of the first and second contact portions with respect to the main body contact portion is a semi-cylindrical curved surface that is convex radially outward with the second direction as its central axis, and the radius of curvature of the main body contact portion is equal to the radius of curvature of the contact surface of each of the first and second contact portions. (vi) The stent delivery device according to (v), wherein the attachment portion has a thread connecting portion to which the restraining thread is connected, a gap is formed between the first contact portion and the second contact portion through which the restraining thread passes, and the thread connecting portion is positioned on the second direction side with respect to the gap.(vii) The stent delivery device according to any one of (i) to (vi), wherein the locking claw is positioned on the opposite side from the second direction with respect to the detachment side contact portion, and the operating receiving portion is positioned on the second direction side with respect to the detachment side contact portion. (viiii) The stent delivery device according to any one of (i) to (vii), wherein when the operating receiving portion is operated in the intersecting direction, the locking claw is permitted to move in the opposite direction to the intersecting direction relative to the main body while maintaining its engagement with the locked portion. (ix) The stent delivery device according to any one of (i) to (viiii), wherein the operating receiving portion has a hole, a recess, or an uneven portion and a surrounding portion surrounding the hole, recess, or uneven portion, and the dimensions of the surrounding portion in a direction perpendicular to the first plane are such that the dimensions of the portion of the surrounding portion located on the second direction side of the hole, recess, or uneven portion are smaller than the dimensions of the portion of the surrounding portion corresponding to the center of the hole, recess, or uneven portion. (x) The stent delivery device according to any one of (i) to (ix), wherein the release operating portion comprises a plurality of attachment / detachment portions distributed around the central axis of the main body, and the plurality of attachment / detachment portions are positioned to fit within the envelope of the main body when viewed in the direction of the central axis. (xi) The stent delivery device according to any one of (i) to (x), wherein the detachable portion is formed in a shape that curves outward radially toward the second direction of the main body.

[0111] This application claims priority based on Japanese Patent Application No. 2025-10710 and Japanese Patent Application No. 2025-10711, both filed on 24 January 2025, and incorporates all of their disclosures herein.

[0112] 10 Outer sheath (sheath) 10a Base end 20 Release operation part 30 Main body part 30a First member 30b Second member 31 Disc part 32 Locking part 32a First locking part 32b Second locking part 32c Second locking part 33 Locking surface 34 Guide surface 34a Edge 35 Opening 35a First opening 35b Second opening 35c Third opening 36 First cylindrical part 37 Second cylindrical part 38 Peripheral wall part 39 Partition wall part 40 Detachable part 40a First detachable part 40b Second detachable part 40c Third detachable part 41 Main part 42 Locking claw 43 Extension pin 43a Outer surface (third direction side surface) 44 Claw part 44a 44b Base end surface 45 Third direction edge 45a Operating receiving part 45a Through hole 45b Concave curved surface 45c Enclosing part 46 Pivot part 46a Gap 47 Thread connecting part 47a Shaft part 47b Flange part 48a Tip side wall-like part 48b Base end side wall-like part 50 Position shift part 51 Main body side contact part 56 Detachable side contact part 57 First contact part 58 Second contact part 60 Inner sheath (sheath) 61a Arrangement section 63 Tip 68 Stent retraction restricting part 70 Inner shaft 80 Handle 100 Stent delivery device 200 Stent 210 Tip part 220 Middle part 230 Base end part 250 Restraint thread 250a First restraint thread 250b Second restraint thread 250c Third restraining thread 251 Base end portion 310, 310a, 310b, 310c First plane 350 Central axis 360 Straight line 370 Envelope of main body 401, 402a, 402b, 403, 404 Imaginary line E1, E2 Point of effort F1, F2, F3a, F3b Support point L1 Point of action

Claims

1. A delivery device capable of transporting a stent, comprising: a long sheath that holds the stent, which is constrained in a reduced diameter state by a restraining thread, at its tip; a release operation unit provided at the base end of the sheath for pulling out the restraining thread toward the base end to release the stent from the restrained state by the restraining thread; the release operation unit comprises: a main body; a detachable part detachably provided to the main body and used with the base end portion of the restraining thread connected to it; the detachable part comprises: a locking claw that is locked to the main body; and an operation receiving part that receives operation by a user; the main body has a locked portion to which the locking claw is locked; the engagement of the locking claw with respect to the locked portion is released when the locking claw moves in a first direction relative to the locked portion; A stent delivery device wherein, when the engagement of the locking claw with the locked portion is released, the detachable portion is pulled out in a second direction intersecting the first direction, thereby detaching the detachable portion from the main body, and when the operating receiving portion is operated in a direction including the second direction component and the intersecting direction component which is a direction intersecting the first plane which is a plane including the first and second directions, the locking claw slides against the locked portion in the opposite direction to the intersecting direction while maintaining its engagement with the locked portion.

2. The stent delivery device according to claim 1, wherein the locking claw comprises: an extension pin extending from the operating receiving portion side in a direction having a directional component opposite to the second direction; and a claw portion provided at the tip of the extension pin in the extension direction and engaging with the locked portion, the locked portion comprises: a guide surface that restricts the movement of the extension pin in a third direction which is opposite to the first direction and guides the extension pin in a direction opposite to the intersecting direction; and a locked surface with which the claw portion engages, the locked surface and the guide surface are connected to and intersect each other via an edge forming their boundary, and the guide surface is curved in a direction that deepens the engagement between the claw portion and the locked surface when the operating receiving portion is operated in a direction perpendicular to a first plane which is a plane including the first direction and the second direction.

3. The release operation unit comprises a plurality of attachment / detachment units distributed around the central axis of the main body, and a plurality of locking units corresponding to each attachment / detachment unit, wherein the first direction is radially inward of the main body, the third direction is radially outward of the main body, the claw portion of the locking claw of each attachment / detachment unit protrudes toward the third direction from the tip of the extension pin of the locking claw, and the guide surface of each locking unit is formed in a convex arc toward the third direction, as described in claim 2.

4. The stent delivery device according to claim 3, wherein the radius of curvature of the guide surface in the circumferential direction of the main body is smaller than the radius of curvature of the third direction side surface of the extension pin.

5. The stent delivery device according to claim 3 or 4, wherein the radius of curvature of the guide surface in the circumferential direction of the main body is smaller than the radius of curvature of the edge on the third direction side of the claw portion.

6. The stent delivery device according to claim 3 or 4, wherein, in the circumferential direction of the main body, the radius of curvature of the third-direction side surface of the extension pin is smaller than the radius of curvature of the third-direction side edge of the claw portion.

7. The stent delivery device according to claim 3 or 4, wherein the detachable portion has a pivot point that serves as a pivot point for the swing relative to the main body when the locking claw moves in the first direction relative to the locked portion.

8. The stent delivery device according to claim 7, wherein the detachable portion has the pivot points on both sides, one side and the other side, with reference to the position of the locking claw, in a direction perpendicular to the first plane.

9. The stent delivery device according to claim 8, wherein the detachable portion has a thread connecting portion to which the restraining thread is connected, a gap is formed between the pivot portion on one side and the pivot portion on the other side through which the restraining thread passes, and the thread connecting portion is positioned at a base end position in the direction of the central axis of the main body portion with respect to the gap.

10. The stent delivery device according to claim 7, wherein the locking claw is positioned at the tip end of the direction of the central axis of the main body with respect to the pivot point, and the operating receiving portion is positioned at the base end of the direction of the central axis of the main body with respect to the pivot point.

11. The operating receiving portion has a hole, a recess, or an uneven portion, and a surrounding portion surrounding the hole, recess, or uneven portion, wherein, with respect to the dimensions of the surrounding portion in a direction perpendicular to the first plane, the dimensions of the portion of the surrounding portion located on the second direction side of the hole, recess, or uneven portion are smaller than the dimensions of the portion of the surrounding portion corresponding to the center of the hole, recess, or uneven portion, according to any one of claims 1 to 4.

12. The stent delivery device according to claim 3 or 4, wherein, when viewed in the direction of the central axis, the plurality of attachment / detachment parts are positioned to fit within the envelope of the main body.

13. The stent delivery device according to claim 12, wherein the detachable portion is formed in a shape that curves outward radially from the main body portion toward the second direction.

Images