Occlusion coil pusher

Abstract

To provide a pusher for an occlusive coil with which a boundary between the occlusive coil and the pusher is easy to visualize under fluoroscopy and which is capable of improving workability of a detention task of the occlusive coil.SOLUTION: A pusher 10 for an occlusive coil is for pushing an occlusive coil composed of a radiopaque material arranged in a catheter and has: a core wire 20 having a base part 21 and an end 23; and a pressing part 30 which is provided at the end 23 of the core wire 20 and presses the occlusive coil. The pressing part 30 has a coil part 31 winding a wire 31a; and an X-ray transmission part 33 which is provided within a range of 10 mm from an endmost part 30a of the pressing part 30 and whose length in an axial direction is 1 to 5 mm. A part adjacent to the X-ray transmission part 33 constitutes a radiopaque part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an occlusion coil pusher for pushing out an occlusion coil used, for example, in treating cerebral aneurysms. [Background technology]

[0002] For example, when treating a cerebral artery or the like, multiple occlusion coils are filled into the aneurysm to block blood flow and prevent rupture, or when administering an anti-cancer drug or the like, an occlusion coil is placed in a specific blood vessel among multiple branched blood vessels to block the blood flow and allow the anti-cancer drug or the like to flow more easily into other blood vessels, thereby treating the affected area.

[0003] The occlusive coil is usually made of a radiopaque material and is pushed out by a pusher to be placed at the desired location. At this time, the occlusive coil is pushed out by the pusher while the boundaries of the occlusive coil and the pusher are visually confirmed under X-ray fluoroscopy (radiofluorography).

[0004] For example, Patent Document 1 listed below describes a pusher wire for a biological indwelling device, which comprises a main wire and a spring coil attached to the outer periphery of the tip of the main wire, and the spring coil is composed of a radiopaque coil portion located at the tip of the main wire and a radiolucent coil portion located adjacent to the base end of the radiopaque coil portion. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4463191 Summary of the Invention [Problem to be solved by the invention]

[0006] In the pusher wire for a biological implantation device disclosed in Patent Document 1, the tip of the spring coil is a radiopaque coil portion made of the same radiopaque material as the occlusive coil. This makes it difficult to visually identify the boundary between the occlusive coil and the radiopaque coil portion (the portion between the base end of the occlusive coil and the tip of the radiopaque coil portion) under X-ray fluoroscopy, which can result in the placement of the occlusive coil taking a long time.

[0007] Therefore, an object of the present invention is to provide a pusher for an occlusive coil that makes it easier to see the boundary between the occlusive coil and the pusher under X-ray fluoroscopy, thereby improving the workability of the occlusive coil placement operation. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention provides an occlusive coil pusher for pushing out an occlusive coil made of an X-ray opaque material placed inside a catheter, the pusher comprising: a core wire having a base and a tip end having a smaller diameter than the base end; and a pressing portion provided at the tip end of the core wire for pressing the occlusive coil, the pressing portion having at least one coil portion formed by winding a wire rod; and an X-ray transparent portion having an axial length of 1 to 5 mm and provided within a range of 10 mm from the tip of the pressing portion, and the portion adjacent to the X-ray transparent portion constitutes an X-ray opaque portion. [Effects of the Invention]

[0009] According to the present invention, an X-ray transparent portion having an axial length of 1 to 5 mm is provided within a range of 10 mm from the most distal end of the pressing portion, and the portion adjacent to the X-ray transparent portion is an X-ray opaque portion, which makes it easier to visualize the boundary between the base end of the occlusive coil and the most distal end of the pressing portion, thereby improving the workability of the occlusive coil placement operation. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing a first embodiment of a pusher for an occlusion coil according to the present invention. [Figure 2]FIG. 10 is an explanatory diagram illustrating the use of the occlusion coil pusher to push out an occlusion coil housed in a catheter. [Figure 3] FIG. 2 is an X-ray fluoroscopic image of the occlusion coil pusher under X-ray fluoroscopy. [Figure 4] FIG. 10 is an explanatory diagram of the state in which the occlusive coil has been pushed out to a predetermined location inside the body using the occlusive coil pusher. [Figure 5] 1A and 1B show a comparative example of a pusher for an occlusion coil, in which (a) is an explanatory side view thereof and (b) is an X-ray fluoroscopic image thereof under X-ray fluoroscopy. [Figure 6] 1(a) is a cross-sectional view showing a second embodiment of an occlusive coil pusher according to the present invention, and FIG. 1(b) is a cross-sectional view showing a third embodiment of an occlusive coil pusher according to the present invention. [Figure 7] 10A and 10B show a fourth embodiment of the pusher for an occlusion coil according to the present invention, in which (a) is a cross-sectional view and (b) is an X-ray fluoroscopic image taken under X-ray fluoroscopy. DETAILED DESCRIPTION OF THE INVENTION

[0011] (First embodiment of the pusher for the occlusion coil) A first embodiment of a pusher for an occlusive coil according to the present invention will be described below with reference to FIGS.

[0012] As shown in Figure 4, for example, an occlusive coil 1 may be placed in an affected area A such as an aneurysm occurring in a tubular organ V such as a blood vessel, or may be placed in a specific blood vessel among multiple branched blood vessels, or may be placed in the body for other specific purposes. This occlusive coil pusher 10 is used to push out the occlusive coil 1 from inside a catheter 5 (see Figure 2) that houses the occlusive coil 1. The occlusive coil 1 is formed by winding a wire made of a radiopaque material such as W, Pt, Ti, Pd, Rh, Au, Ag, Bi, Ta, or an alloy thereof.

[0013] As shown in Figure 1, this first embodiment of a pusher 10 for an occlusive coil (hereinafter also referred to simply as "pusher 10") has a core wire 20 having a base 21 and a tip 23 that is smaller in diameter than the base 21, and a pressing portion 30 that is provided at the tip 23 of the core wire 20 and presses the occlusive coil 1.

[0014] In the following explanation, the "base end" or "base end" of each component such as the core wire 20 or the pressing portion 30 means the end or end (proximal end, proximal end) that is closest to the hand of the user using the occlusion coil pusher, and the "tip end" or "tip" means the end or end (distal end, distal end) opposite the base end or base end.

[0015] The core wire 20 in this embodiment is a round wire with a circular cross section, and has a base portion 21 that extends a predetermined length with a constant outer diameter, and a tip portion 23 that is connected to the tip side of the base portion 21 and has a smaller diameter than the base portion 21. The tip portion 23 is made up of a first tapered portion 24 that extends from the tip of the base portion 21 while gradually reducing in diameter toward the tip of the core wire, a first straight portion 25 that extends linearly from the tip of the first tapered portion 24 with a constant outer diameter, a second tapered portion 26 that extends from the tip of the first straight portion 25 while gradually reducing in diameter toward the tip of the core wire, and a second straight portion 27 that extends linearly with a constant outer diameter from the tip of the second tapered portion 26. In this embodiment, the tip 27a of the second straight portion 27 is the very front end of the core wire 20.

[0016] The pressing portion 30 has at least one coil portion 31 formed by winding a wire 31a, and an X-ray transparent portion 33 located within a range of 10 mm from the tip 30a of the pressing portion 30 (see L1 in Figure 1) and having an axial length L2 of 1 to 5 mm, and the portion adjacent to the X-ray transparent portion 33 forms an X-ray opaque portion.

[0017] More specifically, the pressing portion 30 in this embodiment has a coil portion 31 arranged on the outer periphery of the second tapered portion 26 of the tip portion 23 of the core wire 20, and an X-ray transparent portion 33 arranged on the outer periphery of the second straight portion 27 of the tip portion 23 of the core wire 20 and located closer to the tip side in the axial direction of the core wire 20 than the coil portion 31.

[0018] In this embodiment, the coil portion 31 is formed by winding a wire rod 31a made of a radiopaque material such as W, Pt, Ti, Pd, Rh, Au, Ag, Bi, Ta, or an alloy thereof. The coil portion 31 constitutes the "radiopaque portion" of the present invention. The coil portion 31 in this embodiment is a loosely wound coil in which adjacent wire rods 31a, 31a are wound with a predetermined gap P1 between them.

[0019] The coil portion 31 forming the radiopaque portion is visually recognized under X-ray fluoroscopy as a darker color than the X-ray transparent portion 33, in this case as black or a color close to black (see X-ray fluoroscopic image G3 in FIG. 3). However, in this embodiment, the X-ray fluoroscopic image G3 of the radiopaque portion is visually recognized as being lighter (brighter) than the X-ray fluoroscopic image G1 of the occlusion coil 1.

[0020] On the other hand, the X-ray transparent portion 33 is in the form of a coil formed by winding wire 33a made of an X-ray transparent material, such as an Fe-based alloy such as stainless steel or piano wire, copper, aluminum, chromium, nickel, titanium, or an alloy thereof. The X-ray transparent portion 33 in this embodiment is a loosely wound coil formed by winding adjacent wires 33a, 33a with a predetermined gap P2 between them. Furthermore, the gap P2 between adjacent wires 33a, 33a in the X-ray transparent portion 33 is larger than the gap P1 between adjacent wires 31a, 31a in the coil portion 31.

[0021] In this embodiment, the wire diameter of the wire 33a forming the X-ray transparent portion 33 is the same as the wire diameter of the wire 31a forming the coil portion 31. Furthermore, in this embodiment, the outer diameter of the X-ray transparent portion 33 is the same as the outer diameter of the coil portion 31.

[0022] Under X-ray fluoroscopy, the X-ray transparent portion 33 appears brighter than the occlusion coil 1 and the X-ray opaque portion, in this case white or close to white (see X-ray fluoroscopy image G2 in Figure 3).

[0023] 1, the tip of coil portion 31 and the base end of X-ray transparent portion 33 are joined by joint 35 made of a fastening material such as metal brazing or adhesive. As a result, X-ray transparent portion 33 is disposed at the tip of pressing portion 30, and coil portion 31 forming the X-ray opaque portion is disposed adjacent to the base end side of X-ray transparent portion 33 in the axial direction, via joint 35. In other words, coil portion 31, which is the X-ray opaque portion, is disposed adjacent to the base end side of X-ray transparent portion 33, via joint 35.

[0024] 1, a filler 37 such as an adhesive, synthetic resin, or wax is filled radially inside the coil portion 31 and the X-ray transparent portion 33. The coil portion 31 and the X-ray transparent portion 33 are fixed to predetermined locations on the tip portion 23 of the core wire 20 via the filler 37.

[0025] The outside of the coil portion 31 and the X-ray transparent portion 33 are covered with a cover 39 made of a resin film formed from, for example, polyurethane, polyether ether ketone (PEEK), nylon elastomer, polyether block amide, polyethylene, polyvinyl chloride, vinyl acetate, fluororesin such as polytetrafluoroethylene (PTFE), perfluoroalkoxy resin (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ETFE), etc., and / or a hydrophilic resin film formed from, for example, polyvinylpyrrolidone, polyethylene glycol, methyl vinyl ether maleic anhydride copolymer, etc.

[0026] As described above, the X-ray transparent portion 33 is provided within a range of 10 mm (see L1 in Figure 1) from the leading end 30a of the pressing portion 30 (the leading end including the cover 39), and the axial length L2 of the X-ray transparent portion 33 is 1 to 5 mm.

[0027] (Variation) The shapes and structures of the core wire, the pressing portion, the coil portion and the X-ray transparent portion that constitute the pressing portion, etc. in the above-described embodiments are not limited to the above-described embodiments.

[0028] For example, the core wire may be formed from wire material with a square cross section, and the tip of the core wire may be shaped to consist of only one or more tapered sections that gradually decrease in diameter toward the axial tip (a shape with no straight sections), or may be shaped to consist of one or more straight sections of a constant outer diameter that are smaller than the base section and are connected in the axial direction (a shape with no tapered sections).

[0029] The pressing portion may have an X-ray opaque portion at its tip and an X-ray transparent portion at a position adjacent to the axial base end (this will be described in the fourth embodiment below). Furthermore, the coil portion constituting the pressing portion may be made of an X-ray transparent material such as stainless steel. The X-ray transparent portion 33 in this embodiment is a loosely wound coil that can expand and contract, but it may also be a tightly wound coil or a member that does not flex (this will be described in the second and third embodiments below). The pressing portion 30 in this embodiment has a cover 39, but this cover 39 need not be present.

[0030] Furthermore, in this embodiment, the outer diameters of the coil portion 31 and the X-ray transparent portion 33 and the wire diameters of the wire rods 31a, 33a forming them are the same, but, for example, the outer diameter and wire diameter of the X-ray transparent portion 33 may be made larger or smaller than the outer diameter and wire diameter of the coil portion 31. Also, the gap P2 between adjacent wire rods 33a, 33a in the X-ray transparent portion 33 may be made smaller than the gap P1 between adjacent wire rods 31a, 31a in the coil portion 31, or may be made the same.

[0031] Furthermore, in this embodiment, there is one coil portion 31 and one X-ray transparent portion 33, but there may be a plurality of coil portions or X-ray opaque portions (this will be explained in the fourth embodiment below). However, even in this case, at least one X-ray transparent portion must be located within a range of 10 mm from the tip of the pressing portion.

[0032] In addition, in this embodiment, the radial inside of the coil portion 31 and the X-ray transparent portion 33 is filled with a filler material 37 made of an adhesive or the like, but the inside of the coil portion or the X-ray transparent portion may not be filled with a filler material and may be left as a gap.

[0033] (Action and effect) Next, the effects of the pusher 10 according to the present invention having the above-described configuration will be described.

[0034] That is, under X-ray fluoroscopy (radiofluorography), while a contrast agent is administered into the body using the well-known Seldinger technique or the like, catheter 5 is guided and moved via a guide wire (not shown) until its tip reaches a predetermined position. Thereafter, the guide wire is removed from catheter 5, and occlusive coil 1 is housed inside catheter 5. As shown by the arrow in FIG. 2 , pusher 10 is inserted from the proximal end 5b side of catheter 5. Then, pressing portion 30 of pusher 10 presses occlusive coil 1, moving it within catheter 5. Finally, occlusive coil 1 is pushed out from distal end 5a of catheter 5, placing occlusive coil 1 in affected area A. When affected area A is an aneurysm or the like, as in this embodiment, multiple occlusive coils 1 are often placed in affected area A, as shown in FIG. 4.

[0035] In this pusher 10, the pressing portion 30 has at least one coil portion 31 formed by winding a wire 31a, and an X-ray transparent portion 33 that is provided within a range of 10 mm from the tip 30a of the pressing portion 30 (see L1 in Figure 1) and has an axial length L2 of 1 to 5 mm, and the portion adjacent to the X-ray transparent portion 33 forms an X-ray opaque portion.

[0036] Therefore, the boundary between the base end 1a of the occlusive coil 1 and the distal end 30a of the pressing portion 30 can be easily visualized under X-ray fluoroscopy.

[0037] in particular, (1) As shown in the X-ray fluoroscopic image G1 of FIG. 3, the occlusive coil 1 made of a radiopaque material is visually recognized under X-ray fluoroscopy as being darker in color than the X-ray transparent portion 33 (here, it is visually recognized as black). (2) As shown in the X-ray fluoroscopic image G2 in FIG. 3, the X-ray transparent portion 33, which is provided within a range of 10 mm from the tip 30a of the pressing portion 30 (see L1 in FIG. 1) and is made of an X-ray transparent material and has an axial length L2 of 1 to 5 mm, is visually recognized under X-ray fluoroscopy as being brighter in color than the occlusion coil 1 and the X-ray opaque portion (coil portion 31) (here, it is visually recognized as being white). (3) As shown in the X-ray fluoroscopic image G3 in Figure 3, the X-ray opaque portion (coil portion 31) made of an X-ray opaque material adjacent to the X-ray transparent portion 33 appears darker than the X-ray transparent portion 33 under X-ray fluoroscopy (here, it appears as a color that is slightly lighter (pale) and closer to black than the occlusion coil 1).

[0038] That is, under X-ray fluoroscopy, from left to right in Figure 3, a black X-ray fluoroscopy image G1 due to the occlusion coil 1, a white X-ray fluoroscopy image G2 due to the X-ray transparent portion 33, and an X-ray fluoroscopy image G3 due to the coil portion 31, which is X-ray transparent and is slightly brighter and closer to black than the occlusion coil 1, can be seen arranged in parallel along the axial direction of the occlusion coil 1 and the pusher 10.

[0039] As a result, a large contrast between black or near-black and white or near-white appears at the boundary between the proximal end 1a of the occlusive coil 1 (see FIG. 2) and the distal end 30a of the pressing portion 30, making it easier to see the boundary between the proximal end 1a of the occlusive coil 1 and the distal end 30a of the pressing portion 30. In addition, in this embodiment, the coil portion 31 made of an X-ray opaque material is disposed adjacent to the X-ray transparent portion 33 located at the distal end 30a of the pressing portion 30. Therefore, between the X-ray fluoroscopic image G1 of the occlusive coil 1 and the X-ray fluoroscopic image G3 of the coil portion 31, an X-ray fluoroscopic image G2 that is brighter or near-white than the X-ray fluoroscopic images G1 and G2 is located. This makes it appear as if a gap has occurred between the proximal end 1a of the occlusive coil 1 and the distal end 30a of the pressing portion 30 (see FIG. 3).

[0040] This makes it easier for the user of the pusher 10 to recognize the base end position (position closer to the hand) of the occlusive coil 1 and the tip position of the pressing part 30 under X-ray fluoroscopy, allowing the user to accurately grasp the pushing status when pushing the occlusive coil 1 out of the tip part 5a of the catheter 5, preventing over-pushing of the occlusive coil 1 and displacement of the placement position of the occlusive coil 1, and improving the workability of the placement operation of the occlusive coil 1. Furthermore, by preventing over-pushing of the occlusive coil 1 by the pressing part 30 of the pusher 10 and resulting displacement of the placement position of the occlusive coil 1, the occlusive coil 1 can be placed accurately at a desired position in the body, and further, damage to internal organs, etc. due to over-pushing of the occlusive coil 1 can be prevented.

[0041] Furthermore, since the pressing portion 30 has at least one coil portion 31 formed by winding a wire 31a, flexibility can be ensured at the tip of the pusher 10, which also improves the ease of placement of the occlusion coil 1.

[0042] 5(a) shows a comparative example of an occlusive coil pusher 100 (hereinafter also referred to simply as "pusher 100"). The pressing portion 30 of this pusher 100 consists only of a coil portion made of an X-ray opaque material, and does not have an X-ray transparent portion 33 like the pusher 10 of the first embodiment. In this case, as shown in FIG. 5(b), under X-ray fluoroscopy, the occlusive coil 1 and the entire pressing portion 30 are both visible as black or nearly black, and the difference in brightness between the base end 1a of the occlusive coil 1 and the tip end 30a of the pressing portion 30 is small, making the boundary between them difficult to see.

[0043] As described above, in this pusher 10, the pressing portion 30 is provided within a range of 10 mm from its tip 30a (see L1 in Figure 1), and has an X-ray transparent portion 33 with an axial length L2 of 1 to 5 mm, thereby achieving the above-mentioned effects; however, if the above conditions are not met, the following will occur.

[0044] In other words, if the axial length L2 of the X-ray transparent portion 33 is less than 1 mm, the X-ray transparent portion 33 becomes difficult to see under X-ray fluoroscopy, making it difficult to recognize the base end position of the occlusion coil 1 and the tip position of the pressing portion 30.

[0045] Furthermore, if the axial length L2 of the X-ray transparent portion 33 exceeds 5 mm, it becomes difficult to distinguish under X-ray fluoroscopy whether the bright color is due to the X-ray transparent portion 33 provided in the pressing portion 30 or due to the increased distance between the base end 1a of the occlusive coil 1 and the distal end 30a of the pressing portion 30, making it difficult to recognize the distal position of the pressing portion 30. As a result, there is a risk that the occlusive coil 1 will be pushed too far with the pusher 10, causing the placement position of the occlusive coil 1 to shift within the body. There is also a risk that pushing the occlusive coil 1 too far will damage internal organs, etc.

[0046] Furthermore, if the X-ray transparent portion 33 is positioned more than 10 mm from the tip 30a of the pressing portion 30, it becomes difficult to recognize the tip position of the pressing portion 30, and therefore when the tip 30a of the pressing portion 30 abuts against the base end 1a of the occlusion coil 1, it becomes difficult to recognize the boundary between the base end 1a of the occlusion coil 1 and the tip 30a of the pressing portion 30, making it difficult to grasp how far the occlusion coil 1 has been pushed out from the tip 5a of the catheter 5.

[0047] In this embodiment, the X-ray transparent portion 33 is disposed at the leading end 30a of the pressing portion 30, as shown in FIG.

[0048] According to this embodiment, the X-ray transparent portion 33 is positioned axially adjacent to the base end 1a of the occlusive coil 1, making it easier to see the boundary between the base end 1a of the occlusive coil 1 and the tip 30a of the pressing portion 30 under X-ray fluoroscopy.

[0049] Furthermore, in this embodiment, the coil portion 31 forms the X-ray opaque portion, and the X-ray transparent portion 33 is formed in a coil shape by winding wire 33a, and the gap P2 between adjacent wires 33a, 33a in the X-ray transparent portion 33 is larger than the gap P1 between adjacent wires 31a in the coil portion 31 forming the X-ray opaque portion (see Figure 1).

[0050] According to the above embodiment, the gap P2 between adjacent wires 33a, 33a in the X-ray transparent portion 33 is larger than the gap P1 between adjacent wires 33a, 33a in the X-ray opaque portion, so X-rays can more easily pass through the X-ray transparent portion 33, and under X-ray fluoroscopy, the boundary between the base end 1 of the occlusive coil 1 made of an X-ray opaque material and the leading end 30a of the pressing portion 30 becomes even easier to see (under X-ray fluoroscopy, the X-ray transparent portion 33 appears whiter, so the difference in brightness between it and the occlusive coil 1 becomes greater, and the boundary between the base end 1 of the occlusive coil 1 and the leading end 30a of the pressing portion 30 becomes easier to see). Furthermore, since the X-ray transparent portion 33 in this embodiment is coil-shaped, flexibility is ensured at the tip of the pusher 10, and the conventional operating feel is maintained, while improving the visibility of the boundary between the base end 1a of the occlusion coil 1 and the tip end 30a of the pressing portion 30 under X-ray fluoroscopy.

[0051] (Second embodiment of the pusher for the occlusion coil) 6(a) shows a second embodiment of the pusher for an occlusion coil according to the present invention. Note that parts that are essentially the same as those in the previous embodiment are given the same reference numerals and their description will be omitted.

[0052] The occlusion coil pusher 10A of the second embodiment (hereinafter also simply referred to as "pusher 10A") differs from the first embodiment in the structure of the pressing portion 30A.

[0053] That is, in this pressing portion 30A, the X-ray transparent portion 33A is not coiled like the X-ray transparent portion 33 in the first embodiment, and is a member that does not flexibly deform. Furthermore, this X-ray transparent portion 33A that does not flexibly deform is disposed at the leading edge 30a of the pressing portion 30A. Note that a X-ray opaque portion that does not flexibly deform may be disposed at the leading edge 30a of the pressing portion 30A.

[0054] According to this embodiment, the X-ray transparent portion 33A or the X-ray opaque portion located at the leading end 30a of the pressing portion 30 is a member that does not flexibly deform, so that the hardness and rigidity can be improved compared to the coil, thereby improving the pushing function of the occlusion coil 1.

[0055] (Third embodiment of the pusher for the occlusion coil) 6(b) shows a third embodiment of the pusher for an occlusion coil according to the present invention. Note that parts that are substantially the same as those in the previous embodiment are given the same reference numerals and their description will be omitted.

[0056] The occlusion coil pusher 10B of the third embodiment (hereinafter also simply referred to as "pusher 10B") differs from the first and second embodiments in the structure of the pressing portion 30B.

[0057] That is, in this pressing portion 30B, the X-ray transparent portion 33B is a member that does not flexibly deform, similar to the X-ray transparent portion 33A of the second embodiment, and the X-ray transparent portion 33B is connected to the tip of the second tapered portion 26 of the tip portion 23 of the core wire 20, and is formed integrally with the core wire 20. That is, the X-ray transparent portion 33B in this embodiment is a part of the pressing portion 30B and also a part of the core wire 20. Moreover, the X-ray transparent portion 33B has a larger diameter than the outer diameter of the second tapered portion 26 of the tip portion 23 of the core wire 20, a tip surface 34 thereof is flat, and a base end surface 36 thereof is inversely tapered, with the amount of protrusion gradually decreasing toward the base portion 21 of the core wire 20.

[0058] In this embodiment, as in the second embodiment, the X-ray transparent portion 33B arranged at the leading end 30a of the pressing portion 30B is made of a material that does not flexibly deform, thereby improving the pushing function of the occlusive coil 1.

[0059] (Fourth embodiment of the pusher for the occlusion coil) A fourth embodiment of the pusher for an occlusion coil according to the present invention is shown in Figure 7. Note that parts that are substantially the same as those in the previous embodiment are given the same reference numerals and their description will be omitted.

[0060] The occlusion coil pusher 10C of the fourth embodiment (hereinafter also simply referred to as "pusher 10C") differs from the first to third embodiments in the structure of the pressing portion 30C.

[0061] That is, in the pressing portion 30C of this embodiment, a plurality of X-ray transparent portions 33C are arranged in the axial direction of the core wire 20, at least one of which is arranged within 10 mm from the distal end 30a of the pressing portion 30C (see L1 in FIG. 7), and another X-ray transparent portion 33C is arranged proximally, i.e., 10 mm closer to the proximal side than the position from the distal end 30a of the pressing portion 30C (see FIG. 7(a)). In addition, the coil portion 31C forms a radiopaque portion, and this radiopaque portion is arranged at the distal end 30a of the pressing portion 30C and is configured to be visually recognized fainter than the occlusion coil 1 under X-ray fluoroscopy (see X-ray fluoroscopic image G3 in FIG. 7(b)).

[0062] More specifically, the pressing portion 30C has three coil portions 31C (forming radiopaque portions) arranged from the tip 27a of the second straight portion 27 of the core wire 20 toward the base portion 21, and an X-ray transparent portion 33C arranged between the coil portions 31C (see FIG. 7(a)). That is, from the very tip of the core wire 20 toward the base portion 21, with the coil portion 31C at the head, a plurality of X-ray transparent portions 33C and coil portions 31C are arranged alternately (three coil portions 31C and two X-ray transparent portions 33C are arranged).

[0063] Also, as shown in Figure 7(b), under X-ray fluoroscopy, from left to right in the figure (from the tip side of the core wire 20 to the base side 21), there are arranged a black X-ray fluoroscopy image G1 due to the occlusion coil 1, an X-ray fluoroscopy image G3 which is slightly brighter and closer to black than the occlusion coil 1 due to the coil part 31C which is an X-ray opaque part, and a white X-ray fluoroscopy image G2 due to the X-ray transparent part 33C, and the following X-ray fluoroscopy images of different brightness, G3 and G2, can be viewed alternately along the axial direction of the pusher 10C.

[0064] In this embodiment, the radiopaque portion (coil portion 31C) is located at the distal end 30a of the pressing portion 30 and is configured to be visible under X-ray fluoroscopy as being fainter than the occlusive coil 1. Therefore, even when the radiopaque portion is located at the distal end 30a of the pressing portion 30C, the boundary between the proximal end 1a of the occlusive coil 1 and the distal end 30a of the pressing portion 30C can be easily seen under X-ray fluoroscopy, making it easier to recognize the proximal end position of the occlusive coil 1 and the distal end position of the pressing portion 30C. As a result, over-pushing of the occlusive coil 1 and deviation of the placement position of the occlusive coil 1 are suppressed, improving the workability of the placement operation of the occlusive coil 1.

[0065] Furthermore, in this embodiment, a plurality of X-ray transparent portions 33C are arranged in the axial direction of core wire 20, with at least one of them being arranged within a range of 10 mm from distal end 30a of pressing portion 30C (see L1 in FIG. 7), and other X-ray transparent portions 33C being arranged on the proximal side thereof. Therefore, for example, even if a plurality of occlusion coils 1 are placed at a predetermined location in the body (here, affected area A such as an aneurysm) and pressing portion 30C is buried among those occlusion coils 1, making it difficult to visualize X-ray transparent portion 33C on the distal side of pressing portion 30C under X-ray fluoroscopy, the position of pressing portion 30C can be estimated by X-ray transparent portion 33C on the proximal side. Furthermore, since pressing portion 30C has a plurality of X-ray transparent portions 33, it is easy to determine the direction of travel of pusher 10C.

[0066] It should be noted that the present invention is not limited to the above-described embodiment, 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]

[0067] 1. Occlusion coil 5 Catheter 10, 10A, 10B, 10C Pusher for occlusion coil (pusher) 20 core wire 21 Base 23 Tip 30, 30A, 30B, 30C Pressing part 30a cutting edge 31 Coil section 33,33A,33B,33C X-ray transparent section

Claims

1. An occlusion coil pusher for pushing out an occlusion coil made of a radiopaque material disposed in a catheter, comprising: a core wire having a base portion and a tip portion whose diameter is smaller than that of the base portion; a pressing portion provided at a tip end of the core wire and configured to press the occlusive coil, the pressing portion has at least one coil portion formed by winding a wire rod, and an X-ray transparent portion that is provided within a range of 10 mm from the tip of the pressing portion and has an axial length of 1 to 5 mm, and a portion adjacent to the X-ray transparent portion forms an X-ray opaque portion; The pusher for an occlusive coil is characterized in that the radiopaque portion is located at the tip of the pressing portion and is configured to be visible under X-ray fluoroscopy in a fainter light than the occlusive coil.

2. the coil portion forms the radiopaque portion, and the radiolucent portion forms a coil shape formed by winding a wire, 2. The occlusive coil pusher according to claim 1, wherein the gaps between adjacent wire rods in the X-ray transparent portion are larger than the gaps between adjacent wire rods in the X-ray opaque portion.

3. The radiopaque portion is a member that does not bend or deform, 2. The occlusion coil pusher according to claim 1, wherein the non-flexible member is disposed at the tip of the pressing portion.

4. a plurality of the X-ray transparent portions are arranged in the axial direction of the core wire; At least one of them is disposed within a range of 10 mm from the tip of the pressing portion, 4. The pusher for an occlusion coil according to claim 1, wherein another of said X-ray transparent portions is disposed on the base side of said pusher.

Images