Retaining and releasing device for blocking coils

Abstract

To provide a holding / releasing device for an embolization coil, by which the embolization coil can be moved, can be accurately adjusted to an indwelling position, and can be easily released from a stopper. A holding / releasing device (10) for an embolization coil comprises a sheath (20), an embolization coil (30) provided so as to come into contact with the tip of the sheath, an operation linear member (40), and a stopper (50) that is inserted into a proximal end portion (37) of the embolization coil (30) and is releasably engaged therein. The sheath (20) and the operation linear member (40) are slid relative to each other, so that a proximal end (37a) of the embolization coil (30) comes into contact with a tip (21a) of the sheath (20), the stopper (50) is disengaged, and the embolization coil (30) is released.

Description

Technical Field

[0001] The present invention relates to a retention and detachment device for an occlusion coil that holds an occlusion coil used, for example, in the treatment of cerebral aneurysms and detaches it at a desired location.

Background Art

[0002] For example, when treating the cerebral arteries or the like, a plurality of occlusion coils are filled into an aneurysm to block blood flow and prevent rupture, or when administering an anticancer agent or the like, among a plurality of branched blood vessels, an occlusion coil is placed in a predetermined blood vessel to block its blood flow, and make it easier to flow an anticancer agent or the like into other blood vessels to treat the affected part.

[0003] As a device for transporting the above occlusion coil to a desired position in the body, Patent Document 1 below describes an extrusion tool-vascular occlusion coil assembly having a helical coil that is a vascular occlusion coil having a proximal end portion and an extrusion tool having a threaded distal end portion.

[0004] In the above assembly, by rotating the extrusion tool in a predetermined direction, the threaded distal end portion engages with the proximal end portion of the vascular occlusion coil, and the vascular occlusion coil is held on the distal end portion side of the extrusion tool. In this state, after transporting the vascular occlusion coil to a predetermined position of the blood vessel, by rotating the extrusion tool in the opposite direction to the above, the vascular occlusion coil detaches from the threaded distal end portion, and the vascular occlusion coil is placed at a predetermined position of the blood vessel.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the assembly described in Patent Document 1, as mentioned above, the process of removing the vascular occlusion coil from the extruder is complicated because the extruder needs to be rotated when removing the vascular occlusion coil.

[0007] Therefore, the object of the present invention is to provide a device for holding and releasing a blocking coil that allows the blocking coil to be moved, enabling precise adjustment of its placement position, and facilitating the removal of the blocking coil from the stopper. [Means for solving the problem]

[0008] To achieve the above objective, the locking coil holding and releasing device according to the present invention comprises a cylindrical sheath, a locking coil disposed on the tip side of the sheath and capable of contacting the tip of the sheath, an operating linear member slidably inserted into the sheath, and a stopper provided at the tip of the operating linear member, inserted into the base end of the locking coil, and detachably engaging with the inner circumference of the base end. The device is configured such that by sliding the sheath and the operating linear member relative to each other, the base end of the locking coil contacts the tip of the sheath, releasing the engagement of the stopper with the inner circumference of the base end of the locking coil, and the locking coil is released from the stopper. [Effects of the Invention]

[0009] According to the present invention, after placing an occlusion coil, positioned at the tip of a sheath via a catheter or the like, in a predetermined position within the body, sliding the sheath and the operating linear member relative to each other causes the base end of the occlusion coil to contact the tip of the sheath, releasing the stopper's engagement with the inner circumference of the base end of the occlusion coil, and detaching the occlusion coil from the stopper, thus facilitating the detachment of the occlusion coil. Furthermore, by pushing and pulling the operating linear member relative to the sheath while the stopper connected to the tip of the operating linear member is engaged with the inner circumference of the base end of the occlusion coil, the occlusion coil can be moved via the operating linear member. This allows for appropriate adjustment of the position of the occlusion coil, enabling precise adjustment of its placement position. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram shows a first embodiment of the occlusion coil holding and releasing device according to the present invention, and is a cross-sectional view of the state in which the occlusion coil is housed and held within the catheter. [Figure 2] This is a cross-sectional view of the occlusion coil retention and release device, showing the occlusion coil exposed from the catheter. [Figure 3] This is a cross-sectional view of the retaining and releasing device for the closing coil, showing the state in which the closing coil has been released from the stopper. [Figure 4] This is an explanatory diagram showing the usage status of the occlusion coil. [Figure 5] The second embodiment of the retaining and releasing device for a blocking coil according to the present invention is shown, where (a) is a cross-sectional view of the state in which the stopper and the blocking coil are engaged, and (b) is a cross-sectional view of the state in which the blocking coil is detached from the stopper. [Figure 6] This shows a third embodiment of the retaining and releasing device for a blocking coil according to the present invention, where (a) is a cross-sectional view of the state in which the stopper and the blocking coil are engaged, and (b) is a cross-sectional view of the state in which the blocking coil is detached from the stopper. [Figure 7] This is a cross-sectional view showing a fourth embodiment of the retaining and releasing device for a blocking coil according to the present invention. [Figure 8] This is a cross-sectional view showing a fifth embodiment of the retaining and releasing device for a blocking coil according to the present invention. [Figure 9] This is a cross-sectional view showing a sixth embodiment of the retaining and releasing device for a blocking coil according to the present invention. [Modes for carrying out the invention]

[0011] (First embodiment of a retaining and releasing device for a blocking coil) A first embodiment of the blocking coil holding and releasing device according to the present invention will be described below with reference to Figures 1 to 4.

[0012] As shown in Figure 4, for example, an occlusion coil 30 may be placed in a lesion A such as an aneurysm in a tubular organ V such as a blood vessel, or in a predetermined blood vessel among multiple branched blood vessels, or in other cases where an occlusion coil 30 is placed in the body for a predetermined purpose. The occlusion coil holding and releasing device 10 makes it possible to hold the occlusion coil 30 to a predetermined position in the body and release it at that position.

[0013] As shown in Figures 1-4, the occlusion coil holding and releasing device 10 (hereinafter also simply referred to as "holding and releasing device 10") of this first embodiment includes a cylindrical sheath 20, an occlusion coil 30 (hereinafter also simply referred to as "coil 30") located on the tip 21a side of the sheath 20 and capable of contacting the tip 21a of the sheath 20, an operating linear member 40 (hereinafter also simply referred to as "linear member 40") slidably inserted into the sheath 20, and a stopper 50 provided at the tip 41 of the linear member 40, inserted into the base end 37 of the coil 30, and detachably engaging with the inner circumference of the base end 37. A cylindrical catheter 15 is also arranged on the outside of the sheath 20.

[0014] Furthermore, as shown in FIGS. 1 and 2, the stopper 50 is normally engaged with the inner periphery of the proximal end portion 37 of the coil 30. Then, as shown by the arrows F1 and F2 in FIG. 2, by relatively sliding the sheath 20 and the linear member 40, as shown in FIG. 3, the proximal end 37a of the coil 30 abuts against the tip 21a of the tip portion 21 of the sheath 20, and the engagement of the stopper 50 with the inner periphery of the proximal end portion 37 of the coil 30 is released, and the coil 30 is configured to be detached from the stopper 50.

[0015] When relatively sliding the sheath 20 and the linear member 40, for example, the sheath 20 can be gripped and fixed, and the linear member 40 can be pulled toward the hand side, pushed to the side opposite to the hand side, or the linear member 40 can be gripped and fixed, and the sheath 20 can be pulled toward the hand side, pushed to the side opposite to the hand side, or the sheath 20 and the linear member 40 can be pushed and pulled against each other.

[0016] In the following description, the "proximal end portion" or "proximal end" means the end portion (proximal end portion) closer to the user's hand when using the holding and detaching device for the closing coil, and the "tip portion" or "tip" means the end portion (distal end portion) on the side opposite to the proximal end portion or proximal end.

[0017] First, the sheath 20 will be described.

[0018] The sheath 20 in this embodiment is cylindrical with a constant outer diameter and a constant inner diameter and extends in the axial direction for a predetermined length. As shown in FIG. 3, the proximal end 37a of the coil 30 abuts against the tip 21a, which is the foremost tip of the tip portion 21 in the axial direction (longitudinal direction) of the sheath 20.

[0019] Outside the sheath 20, a catheter 15 is positioned, which, like the sheath 20, is cylindrical in shape, having a constant outer diameter and a constant inner diameter, and extending axially for a predetermined length. The catheter 15 and the sheath 20 are slidable relative to each other. Furthermore, as shown in Figure 1, an occlusion coil 30 is housed inside the tip portion 15a of the catheter 15. Preferably, the catheter 15 has a lumen through which a guide wire can be inserted.

[0020] The catheter 15 and sheath 20 described above are formed from materials such as polyethylene (PE), fluororesin, polyoxymethylene (POM), polypropylene (PP), nylon resin, nylon elastomer, polyester, ABS resin, polycarbonate, polyetheretherketone (PEEK), and polyimide.

[0021] Next, the blocking coil 30 will be described.

[0022] In this embodiment, the blocking coil 30 is a coil (a tightly wound coil in this embodiment) made by winding a wire 31 of a constant diameter at a predetermined pitch. Furthermore, a rounded head 35 is fixed to the axial tip 33 of the coil 30 via metal solder or adhesive, making it less likely to damage the tubular organ V when the coil 30 moves.

[0023] Furthermore, as shown in Figure 2, the outer diameter of the coil 30 in this embodiment is smaller than the outer diameter of the sheath 20 and larger than the inner diameter. Therefore, the base end 37a, which is the very base end of the axial base end 37 of the coil 30, can come into contact with the tip 21a of the tip end 21 of the sheath 20 (see Figure 3).

[0024] The coil 30 may be molded into a predetermined shape. In this embodiment, for the sake of explanation, the coil 30 is shown as straight when it is housed and held inside the catheter 15 (see Figure 1) and when it is exposed from the inner circumference of the tip 15a of the catheter 15 (see Figures 2 and 3). However, in reality, as shown in Figure 4, when the coil 30 is exposed from the inside of the tip 15a of the catheter 15, it returns to its predetermined shape.

[0025] Furthermore, the above-mentioned blocking coil 30 can be made of, for example, superelastic alloys such as Ni-Ti alloys, Ni-Ti-X (X=Fe, Cu, V, Co, Cr, Mn, Nb, etc.) alloys, Cu-Zn-X (X=Al, Fe, etc.) alloys, stainless steel, piano wire, etc. Alternatively, an X-ray opaque metal consisting of W, Pt, Ti, Pd, Rh, Au, Ag, Bi, Ta, and alloys thereof can be used.

[0026] Next, the operating linear member 40 will be described.

[0027] In this embodiment, the linear member 40 is a linear (wire-like) member extending with a constant diameter, and is slidably inserted into the sheath 20. A stopper 50 is connected to and integrated with the axial end 41 of the linear member 40.

[0028] The linear member 40 described above can be made of, for example, a superelastic alloy such as a Ni-Ti alloy, a metal wire such as stainless steel or piano wire, or a resin wire such as polyethylene (PE) or polyethylene terephthalate (PET).

[0029] Next, I will explain stopper 50.

[0030] In this embodiment, the stopper 50 is cylindrical in shape, extending from its base end to its tip with a constant diameter and a predetermined length. Furthermore, the stopper 50 is separate from the linear member 40 and is connected to the tip 41 of the linear member 40. In addition, the stopper 50 is inserted into the base end 37 of the coil 30 and is detachably engaged with the inner circumference of the base end 37 (see Figures 2 and 3).

[0031] In this embodiment, as shown in Figure 3, the outer diameter R1 of the stopper 50 is formed to be slightly larger than the inner diameter R2 of the blocking coil 30. Therefore, when the stopper 50 is inserted into the base end 37 of the coil 30, the outer circumference of the stopper 50 is pressed against the inner circumference of the base end 37 of the coil 30, causing the stopper 50 to engage with the inner circumference of the base end 37 of the coil 30 (see Figures 1 and 2).

[0032] Furthermore, in this holding and releasing device 10, when (1) the coil 30 is moved via the linear member 40 with the stopper 50 engaged with the inner circumference of the base end 37 of the coil 30, the force that causes the coil 30 to detach from the inner circumference of the base end 37 of the coil 30 is defined as the "disengagement force during coil movement", (2) the engagement force between the inner circumference of the base end 37 of the coil 30 and the stopper 50 is defined as the "engagement force between the coil and the stopper", and (3) the force that causes the stopper 50 to detach from the inner circumference of the base end 37 of the coil 30 due to the relative sliding motion between the sheath 20 and the linear member 40 is defined as the "disengagement force of the stopper from the coil", the relationship between these forces is set as follows.

[0033] In other words, in this holding and releasing device 10, the engagement force between the coil and the stopper is greater than the release force when the coil moves, and the force that releases the stopper from the coil is greater than this engagement force (release force when coil moves < engagement force between coil and stopper < force that releases the stopper from the coil).

[0034] As a result, the coil 30 and the stopper 50 perform the following actions.

[0035] In other words, as shown in Figure 2, when the coil 30 is exposed from the inside of the tip 15a of the catheter 15 and the stopper 50 is engaged with the inner circumference of the base end 37 of the coil 30, when the coil 30 is moved away from the tip 21a of the sheath 20 via the linear member 40, as shown by arrow F1 in Figure 2, or when the coil 30 is moved closer to the tip 21a of the sheath 20 via the linear member 40, as shown by arrow F2 in Figure 2 (the case when the coil 30 is close to the tip 21a of the sheath 20 will be described later), the "disengagement force during coil movement" is smaller than the "engagement force between the coil and the stopper". Therefore, even if an external force acts unexpectedly during coil movement, if that external force is smaller than the "engagement force between the coil and the stopper", the engagement between the coil 30 and the stopper 50 is maintained, and the stopper 50 is prevented from disengaging from the inner circumference of the base end 37 of the coil 30. As a result, the coil 30 can be pushed and pulled via the linear member 40.

[0036] Furthermore, as shown in Figure 2, when the coil 30 is exposed from the inside of the tip 15a of the catheter 15, and the stopper 50 is engaged with the inner circumference of the base end 37 of the coil 30, and the sheath 20 and the linear member 40 are slid relative to each other in the direction of arrow F2 in Figure 2, the stopper 50 moves towards the proximal side via the linear member 40, and as shown in Figure 3, the base end 37a of the coil 30 comes into contact with the tip 21a of the sheath 20. At this time, the "force to disengage the stopper from the coil" is greater than the "engagement force between the coil and the stopper", so even if the base end 37a of the coil 30 comes into contact with the tip 21a of the sheath 20, as long as the force is less than the "force to disengage the stopper from the coil", the stopper 50 will not come off the inner circumference of the base end 37 of the coil 30. In other words, unless the operator of the holding and releasing device 10 intentionally applies a "force to disengage the stopper from the coil", the coil 30 will not come off the stopper 50. Therefore, in this case as well, the ability to push and pull the coil 30 via the linear member 40 is maintained.

[0037] Then, as shown in Figure 3, with the base end 37a of the coil 30 in contact with the tip 21a of the sheath 20, if the operator of the holding and releasing device 10 intentionally applies a force greater than the "engagement force between the coil and the stopper" to pull the linear member 40 toward the operator, the stopper 50 will detach from the inner circumference of the base end 37 of the coil 30 (the engagement of the stopper 50 with the inner circumference of the base end 37 of the coil 30 will be released), the coil 30 will detach from the stopper 50, and the stopper 50 will be inserted into the sheath 20.

[0038] The stopper 50 described above can be made of, for example, elastic materials such as rubber, porous materials such as sponge, metallic materials such as Ni-Ti alloys and stainless steel, or resin materials such as polyethylene (PE) or polyethylene terephthalate (PET).

[0039] (modified version) The shapes and structures of the catheter, sheath, occlusion coil, operating wire member, and stopper in the embodiments described above are not limited to those described above.

[0040] For example, the catheter or sheath may have a tapered shape that gradually narrows or widens towards the tip or proximal end in the axial direction (the shape in which the sheath tip is tapered will be explained in the fifth embodiment shown in Figure 8), or it may have a shape that gradually narrows or widens towards the tip or proximal end in the axial direction, or it may have narrowed or widened sections in the middle of the axial direction.

[0041] Furthermore, the blocking coil may be a coil in which wire is wound with a predetermined gap (a loosely wound coil), or a coil in which tightly wound and loosely wound sections are appropriately combined, or a reduced diameter shape may be provided at the tip or base of the coil (the shape in which the base end has a reduced diameter will be explained in the fifth embodiment shown in Figure 8), and it is sufficient that a stopper can be engaged with and disengaged from the inner circumference of the base end.

[0042] Furthermore, radiopaque markers may be placed at designated locations on the sheath, occlusion coil, and stopper.

[0043] Furthermore, the linear member may be a hollow cylindrical member (tube) in addition to a solid wire such as a wire, or a combination of a solid wire and a hollow cylindrical member (as explained in the fourth embodiment shown in Figure 7), as long as it is a linear member extending for a predetermined length, slidably inserted into the sheath, and to which a stopper can be attached.

[0044] Furthermore, in addition to a cylinder of a fixed diameter, the stopper may also be, for example, (1) having a spiral projection on its outer circumference (explained in the sixth embodiment shown in Figure 9), (2) being spherical, (3) having an elliptical cross-section, (4) having a roughly drum-like shape with a bulge in the axial center and gradually narrowing towards both axial ends, (5) having a tapered shape with the outer circumference gradually decreasing in diameter towards the axial tip or base end (the shape that decreases in diameter towards the base end will be explained in the fifth embodiment shown in Figure 8), (6) being coil-shaped (explained in the second embodiment shown in Figure 5), (7) being stent-shaped (explained in the third embodiment shown in Figure 6), or (8) having a polygonal shape on its outer circumference, as long as it can engage with and disengage from the inner circumference of the base end of the closure coil.

[0045] Furthermore, although the stopper 50 in this embodiment is separate from the linear member 40, the stopper may be integrally formed with the tip side of the linear member, and is not particularly limited.

[0046] (Effects and Benefits) Next, an example of how to use the holding and releasing device 10 according to the present invention, which has the above configuration, will be described. Note that this method of use is just an example and is not particularly limited.

[0047] First, as shown in Figure 1, the coil 30 is housed and held on the inner circumference of the tip 15a of the catheter 15. In this state, the stopper 50 is engaged with the inner circumference of the base end 37 of the coil 30, which is located on the tip 21a side of the sheath 20, and the coil 30 can be moved via the stopper 50 by pushing and pulling the linear member 40.

[0048] Then, using a well-known method such as the Seldinger technique, the catheter 15 is guided and moved via a guidewire (not shown) until its tip 15a reaches a predetermined position. Here, as shown in Figure 4, the tip 15a of the catheter 15 is inserted into the affected area A, such as an aneurysm. After exposing the tip 21 of the sheath 20 and the coil 30 from the tip 15a of the catheter 15, as shown by arrow F2 in Figure 2, for example, by gripping and fixing the sheath 20 and pulling the linear member 40 towards the proximal end, the sheath 20 and the linear member 40 are made to slide relative to each other. This causes the stopper 50 to move towards the proximal end via the linear member 40, and as shown in Figure 3, the base end 37a of the coil 30 comes into contact with the tip 21a of the sheath 20. Furthermore, by pulling the linear member 40 towards the user, the aforementioned "force to release the stopper from the coil" is intentionally applied, causing the stopper 50 to detach from the inner circumference of the base end 37 of the coil 30. This allows the coil 30 to be detached from the stopper 50, and the coil 30 to be placed in the affected area A. In the case of an aneurysm or the like, multiple coils 30 are placed in the affected area A, as shown in Figure 4.

[0049] Thus, in this retaining and releasing device 10, after the coil 30, which is positioned on the tip 21a side of the sheath 20, is placed in a predetermined position inside the body via a catheter 15 or the like, the sheath 20 and the linear member 40 are slid relative to each other. When the base end 37a of the coil 30 comes into contact with the tip 21a of the sheath 20, the engagement of the stopper 50 with the inner circumference of the base end 37 of the coil 30 is released, and the coil 30 is released from the stopper 50, making the release of the coil 30 easy.

[0050] Furthermore, if the coil 30 exposed from the inside of the tip 15a of the catheter 15 is misaligned with respect to the affected area A, it may be desirable to correct the position of the coil 30. In this case, the stopper 50 connected to the tip 41 of the linear member 40 engages with the inner circumference of the base end 37 of the coil 30, and the linear member 40 is pushed or pulled against the sheath 20, thereby moving the coil 30 via the linear member 40, allowing the position of the coil 30 to be corrected as appropriate. As a result, the placement position of the coil 30 can be adjusted with high precision. As described above, in this holding and releasing device 10, unless the operator intentionally applies a "force to disengage the stopper from the coil" that is greater than the "engagement force between the coil and the stopper," the stopper 50 will not disengage from the inner circumference of the base end 37 of the coil 30, thus maintaining the push-pull operation of the coil 30.

[0051] (Second embodiment of a retaining and releasing device for a blocking coil) Figure 5 shows a second embodiment of the coil holding and releasing device for blocking according to the present invention. Parts substantially identical to those in the previous embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0052] The retaining and releasing device 10A for the occlusion coil in this second embodiment (hereinafter also simply referred to as "retaining and releasing device 10A") differs from that in the first embodiment in the structure of the stopper 50A. For the sake of explanation, the catheter 15 is omitted (the same applies to the third to sixth embodiments below).

[0053] In this second embodiment, the stopper 50A is in the shape of a coil formed by winding a wire 51. Specifically, the stopper 50A is a loosely wound coil formed by winding the wire 51 with predetermined gaps between them, and extends with a constant outer diameter. Furthermore, the outer diameter of the stopper 50A is formed to be larger than the inner diameter of the coil 30. In addition, the tip 41 of the linear member 40 is connected to the base end 51a of the stopper 50A.

[0054] Furthermore, the stopper 50A has an outer shape that can be pressed against the inner circumference of the coil 30, and is configured to extend and reduce in diameter in the axial direction of the coil 30 and the sheath 20 during the relative sliding motion between the sheath 20 and the linear member 40, thereby releasing the engagement of the base end 37 of the coil 30 with the inner circumference and detaching from the coil 30.

[0055] In other words, in this embodiment, the stopper 50A is formed with an outer diameter larger than the inner diameter of the coil 30, so as shown in Figure 5(a), under normal circumstances, its entire outer circumference is pressed against the inner circumference of the base end 37 of the coil 30. When the sheath 20 and the linear member 40 are slid relative to each other, and the stopper 50A is pulled via the linear member 40, as shown in Figure 5(b), the stopper 50A extends in the axial direction of the coil 30 and the sheath 20 and its diameter decreases, so that the engagement with the inner circumference of the base end 37 of the coil 30 is released, and the coil 30 is detached from the stopper 50A.

[0056] In this invention, "having an outer shape that can be pressed against the inner circumference of the closure coil" means that at least a part of the outer shape of the stopper can be pressed against the inner circumference of the closure coil, and it is not necessary for the entire outer shape of the stopper to be pressed against the inner circumference of the closure coil (for example, if the stopper has a reduced diameter portion at the tip, base, or middle, the reduced diameter portion will not be pressed against the inner circumference of the coil). Furthermore, the "outer shape" of the stopper includes not only those having a continuous "outer circumference" in the circumferential direction, such as a coil shape as in the second embodiment, but also, for example, an outer shape that meanders along the axial direction of the sheath.

[0057] In this embodiment, after the coil 30 is placed in a predetermined position inside the body, the sheath 20 and the linear member 40 are slid relative to each other in order to detach the coil 30 from the stopper 50A. As a result, the stopper 50A extends in the axial direction of the coil 30 and the sheath 20 and shrinks in diameter, releasing the engagement of the base end 37 of the coil 30 with the inner circumference, and the coil 30 detaches from the stopper 50A. Therefore, a large force is not required when detaching the stopper 50A from the coil 30, reducing the recoil when the stopper is detached and suppressing the displacement of the coil 30 caused by the recoil.

[0058] Furthermore, in this embodiment, since the stopper 50A is in the shape of a coil formed by winding the wire 51, the flexibility of the stopper 50A itself can be increased, making it easier to implant the occlusion coil 30 inside the body.

[0059] (Third embodiment of a retaining and releasing device for a blocking coil) Figure 6 shows a third embodiment of the coil holding and releasing device for blocking according to the present invention. Parts substantially identical to those in the previous embodiments are denoted by the same reference numerals, and their descriptions are omitted.

[0060] The retaining and releasing device 10B for the blocking coil of this third embodiment (hereinafter also simply referred to as "retaining and releasing device 10B") has a different structure for the stopper 50B compared to the previous embodiment.

[0061] In other words, the stopper 50B in this third embodiment is a cylindrical stent made by weaving and / or assembling metal wires. Alternatively, the stopper 50B may be a cylindrical stent made by providing a plurality of mesh-like openings formed by laser cutting in the circumferential direction of a metal cylinder. Furthermore, the base end 53 of the stopper 50B has a tapered shape that gradually decreases in diameter towards the base end 53a in the axial direction. The base end 53a of the stopper 50B is connected to the tip 41 of the linear member 40.

[0062] Furthermore, in this third embodiment of the retaining and releasing device 10B, similar to the retaining and releasing device 10A of the second embodiment, the stopper 50B has an outer shape that can be pressed against the inner circumference of the coil 30, and is configured to extend and reduce in diameter in the axial direction of the coil 30 and the sheath 20 during the relative sliding motion between the sheath 20 and the linear member 40, thereby releasing the engagement of the base end 37 of the coil 30 with the inner circumference and detaching from the coil 30.

[0063] In the holding and releasing device 10B of this embodiment, since the stopper 50B is stent-shaped, when the sheath 20 and the linear member 40 are slid relative to each other to extend the stopper 50B in the axial direction of the coil 30 and the sheath 20 and reduce its diameter, the tensile force from the linear member 40 is more likely to act on the stopper 50B in the axial and circumferential directions. As a result, it becomes easier to reduce the diameter of the stopper 50B, and the ease of releasing the coil 30 from the stopper 50B can be improved.

[0064] (Fourth embodiment of a retaining and releasing device for a blocking coil) Figure 7 shows a fourth embodiment of the coil holding and releasing device for blocking according to the present invention. Parts substantially identical to those in the previous embodiments are denoted by the same reference numerals, and their descriptions are omitted.

[0065] The retaining and releasing device 10C for the blocking coil of this fourth embodiment (hereinafter also simply referred to as "retaining and releasing device 10C") has a different structure for the operating linear member 40C compared to the previous embodiment.

[0066] In other words, this operating linear member 40C (hereinafter also simply referred to as "linear member 40C") has a cylindrical tube 43 and a linear wire 45 that is slidably inserted into the tube 43. Furthermore, the stopper 50C in this embodiment is a tightly wound coil and is pressed against the inner circumference of the base end 37 of the coil 30, allowing it to engage with and disengage from the coil 30. In addition, the tip 43a of the tube 43 is connected to the base end of the stopper 50C.

[0067] The outer diameter of the wire 45 is sized to fit the inner diameter of the stopper 50C. The tip 45a of the wire 45 is inserted into the inner circumference of the stopper 50C, thereby restricting the reduction in diameter of the stopper 50C.

[0068] In this embodiment, as shown in Figure 7, the reduction in diameter of the stopper 50C is restricted by the tip 45a of the wire 45. Therefore, when an unexpected external force acts on the coil during movement via the linear member 40C, the coil 30 is prevented from detaching from the stopper 50C, making it easier to position the coil 30 in a predetermined location within the body.

[0069] (Fifth embodiment of a retaining and releasing device for a blocking coil) Figure 8 shows a fifth embodiment of the coil holding and releasing device for blocking according to the present invention. Parts substantially identical to those in the previous embodiments are denoted by the same reference numerals, and their descriptions are omitted.

[0070] In this fifth embodiment, the retaining and releasing device 10D for the blocking coil (hereinafter also simply referred to as "retaining and releasing device 10D") differs from the previous embodiment in the shape of the blocking coil 30D (hereinafter also simply referred to as "coil 30D") and the shape of the stopper 50D.

[0071] As shown in Figure 8, the tip 21 of the sheath 20D has a shape that gradually decreases in diameter towards the axial tip 21a (extentmost point).

[0072] Furthermore, the coil 30D has a shape in which its base end 37 gradually decreases in diameter towards the axial base end 37a (the very base). The base end 37a of this coil 30D can come into contact with the tip 21a of the sheath 20D.

[0073] Furthermore, the stopper 50D is columnar in shape, and the shape of its outer circumference 55 (outer shape) is such that it conforms to the shape of the base end 37 of the stopper 50D. The axial base end 55a (very base) is the smallest in diameter, and the diameter gradually widens towards the axial tip 55b (very tip). In addition, the outer diameter dimension of the outer circumference 55 of the stopper 50D is formed to be slightly smaller than the inner diameter dimension of the base end 37 of the coil 30D. Therefore, when the stopper 50D is inserted into the inner circumference of the base end 37 of the coil 30D, a predetermined gap is formed between the inner circumference of the base end 37 of the coil 30D and the outer circumference 55 of the stopper 50D.

[0074] In the above-described retaining and releasing device 10D, after the coil 30 is placed in a predetermined position inside the body, the sheath 20 and the linear member 40 are slid relative to each other in order to release the coil 30D from the stopper 50D. As a result, the stopper 50D is gradually pulled out from the base end opening 37b of the coil 30D while pushing open the base end 37 of the coil 30D. Once the stopper 50D is completely removed from the base end opening 37b of the coil 30D, the coil 30D can be released from the stopper 50D.

[0075] In this embodiment, the coil 30D has a base end 37 that gradually decreases in diameter towards the base end 37a, and corresponding to the base end shape of the coil 30D, the stopper 50D has an outer shape that gradually increases in diameter towards the tip 55b. Therefore, when the stopper 50D is inserted into the base end 37 of the coil 30D, the gradually increasing diameter portion of the stopper 50D is positioned opposite the gradually decreasing diameter portion of the base end 37 of the coil 30D. As a result, even if the linear member 40 is pulled towards the user, the stopper 50D is less likely to come out of the base end opening 37b of the coil 30D, thereby increasing the engagement force between the stopper 50D and the coil 30D.

[0076] Furthermore, since it becomes easier to create a gap between the inner circumference of the base end 37 of the coil 30D and the outer circumference of the stopper 50D (even without tight contact, the stopper 50D is less likely to come out of the base end opening 37b of the coil 30D), this gap can be used to circulate, for example, sterilization gas into the coil 30D.

[0077] Furthermore, since the outer shapes of the base end 37 of the coil 30D and the stopper 50D are as described above, there is no need to make the outer diameter of the stopper 50D larger than the inner diameter of the coil 30D, and even if the stopper 50D is inserted into the inner circumference of the base end 37 of the coil 30D, an increase in the outer diameter of the base end 37 of the coil 30D can be suppressed. As a result, it becomes easier to slide the coil 30D and the sheath 20 against the catheter 15, etc. (Effects of claim 5 above). Note that in the case of a retaining and releasing device for an occlusion coil other than the retaining and releasing device 10D of this fifth embodiment, the outer diameter of the base end 37 of the coil 30 on which the stopper is placed is slightly larger than the outer diameter of the coil 30 other than the base end 37 on which the stopper is not placed.

[0078] (Sixth embodiment of a retaining and releasing device for a blocking coil) Figure 9 shows a sixth embodiment of the coil holding and releasing device for blocking according to the present invention. Parts substantially identical to those in the previous embodiments are denoted by the same reference numerals, and their descriptions are omitted.

[0079] The retaining and releasing device 10E for the blocking coil of this sixth embodiment (hereinafter also simply referred to as "retaining and releasing device 10E") has a different shape for the stopper 50E compared to the previous embodiment.

[0080] In other words, the stopper 50E of this embodiment has a cylindrical body 58 that extends for a fixed diameter and predetermined length, and projections 59 that are continuously provided on the outer circumference of the body 58 in a spiral shape. As shown in Figure 9, the projections 59 can be inserted into the gaps between adjacent wires 31, 31 of the coil 30 and engage with or disengage from it.

[0081] As described above, the stopper, which can engage with and disengage from the gap between the wires 31, 31 of the coil 30, may, for example, have projections extending circumferentially or annular projections regularly or irregularly provided on the outer circumference of the main body 58.

[0082] In this embodiment, the projection 59 of the stopper 50E engages with and disengages from the gap between the wires 31, 31 of the coil 30, thereby improving the engagement force between the coil 30 and the stopper 50E while suppressing an increase in the outer diameter of the coil 30. Furthermore, since the outer diameter of the body 58 of the stopper 50E can be made smaller than the inner diameter of the coil 30, it becomes easier to create a gap between the inner circumference of the coil 30 and the outer circumference of the stopper 50E, allowing sterilization gas and the like to circulate inside the coil 30.

[0083] It should be noted that the present invention is not limited to the embodiments described above, and various modified embodiments are possible within the scope of the gist of the present invention, and such embodiments are also included in the scope of the present invention. [Explanation of Symbols]

[0084] 10, 10A, 10B, 10C, 10D, 10E Closure coil holding and release device (holding and release device) 15 Catheter 15a Tip 20, 20D sheath 21a Tip 30,30D occlusion coil 37a proximal end 40,40C Operating Linear Member (Linear Member) 43 Tubes 45 wires 50, 50A, 50B, 50C, 50D, 50E Stopper

Claims

1. A cylindrical sheath, A blocking coil is positioned at the tip of the sheath and is capable of contacting the tip of the sheath, A linear operating member is slidably inserted into the sheath, The operating linear member has a stopper provided at its tip, which is inserted into the base end of the closing coil and engages with the inner circumference of the base end in a detachable manner. The configuration is such that by sliding the sheath and the operating linear member relative to each other, the base end of the blocking coil comes into contact with the tip of the sheath, releasing the engagement of the stopper with the inner circumference of the base end of the blocking coil, and the blocking coil detaches from the stopper. A device for holding and releasing a blocking coil, characterized in that the stopper has an outer shape that can be pressed against the inner circumference of the blocking coil, and is configured such that when the sheath and the operating linear member slide relative to each other, the blocking coil and the sheath extend in the axial direction and contract in diameter, releasing the engagement of the base end of the blocking coil with the inner circumference, and the blocking coil detaches from the stopper.

2. The retaining and releasing device for a blocking coil according to claim 1, wherein the stopper is in the shape of a coil formed by winding a wire.

3. A cylindrical sheath, A blocking coil is positioned at the tip of the sheath and is capable of contacting the tip of the sheath, A linear operating member is slidably inserted into the sheath, The operating linear member has a stopper provided at its tip, which is inserted into the base end of the closing coil and engages with the inner circumference of the base end in a detachable manner. The configuration is such that by sliding the sheath and the operating linear member relative to each other, the base end of the blocking coil comes into contact with the tip of the sheath, releasing the engagement of the stopper with the inner circumference of the base end of the blocking coil, and the blocking coil detaches from the stopper. The aforementioned operating linear member is, Tube and, It has a wire that is slidably inserted into the tube, The tip of the tube is connected to the stopper, A device for holding and releasing a blocking coil, characterized in that the tip of the wire is inserted into the inner circumference of the stopper, thereby restricting the reduction in diameter of the stopper.

4. A cylindrical sheath, A blocking coil is positioned at the tip of the sheath and is capable of contacting the tip of the sheath, A linear operating member is slidably inserted into the sheath, The operating linear member has a stopper provided at its tip, which is inserted into the base end of the closing coil and engages with the inner circumference of the base end in a detachable manner. The configuration is such that by sliding the sheath and the operating linear member relative to each other, the base end of the blocking coil comes into contact with the tip of the sheath, releasing the engagement of the stopper with the inner circumference of the base end of the blocking coil, and the blocking coil detaches from the stopper. The aforementioned blocking coil has a shape in which its base end gradually decreases in diameter towards the base end. The stopper is characterized in that its outer shape gradually widens towards the tip, making it a device for holding and releasing a blocking coil.

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