JP2014188039A - Steerable catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steerable catheter that can prevent formation of wrinkles in a tip part with deflection of the tip part.SOLUTION: A substantially cylindrical ring 24 is provided at the tip side of a sheath 2, and a tip body 25a of a distal tip 25 is provided at the further tip side of the ring. A coated tube 25b is integrally formed at the base end side of the tip body. The coated tube is fusion-bonded at the tip part of the sheath, while the ring and a tip part 2a of the sheath is interpolated in the coated tube, and a surface 24a of the ring is to be a rough surface (arithmetic average roughness Ra is 0.5 μm or more).

Description

  The present invention relates to a catheter that is a medical treatment instrument used for performing various treatments, examinations, and the like, and in particular, relates to a steerable catheter that can freely deflect a distal end portion.

  For catheters (including electrode catheters, ablation catheters, and catheter sheaths) that are inserted through body cavities, lumens, blood vessels, or the like to target tissues such as various organs (for example, the heart). In order to facilitate the approach of the catheter, the direction of the vicinity of the distal end (tip portion) of the catheter inserted into the body can be deflected by operating the operation portion provided at the proximal end portion of the catheter disposed outside the body. Such a tip movable catheter is known (see Patent Document 1 and Patent Document 2).

  The portion to be deflected of the distal end portion of the catheter tube of the distal end movable catheter is set, for example, so that the hardness thereof is gradually reduced toward the distal end, and a ring (pull ring) made of a substantially cylindrical metal is disposed at the distal end. Furthermore, a substantially cylindrical chip (tip chip) made of resin is disposed. The tip of the tip, the ring, and the catheter tube are integrally attached to each other by being inserted into a thin coated tube and fused to the tip of the tip and the catheter tube.

  The distal ends of the pair of wires are connected to the 180 ° facing position of the ring, and on one base end side of the pair of wires, one wire (first wire) is pulled, and the other wire (second wire) ) Is controlled so that the orientation of the tip of the catheter tube can be controlled.

Utility Model Registration No. 3161837 Utility Model Registration No. 3162588

  However, according to the prior art, when the catheter tube is deflected relatively large (for example, up to about 180 °), the inner side of the portion covering the surface of the ring of the covering tube (the side with the large curvature) is one. In some cases, wrinkles (swelling) occurred in the part (see reference numeral S in FIG. 7). The occurrence of such wrinkles needs to be prevented because it may interfere with the operation of the catheter tube or treatment using the catheter tube.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a tip movable catheter that can prevent generation of wrinkles at the distal end accompanying deflection of the distal end of the catheter tube. To do.

  A tip movable catheter according to the present invention includes a catheter tube, a substantially cylindrical ring member provided on the distal end side of the catheter tube, a substantially cylindrical tip body provided further on the distal end side of the ring member, and the tip body. A tip member having a covering tube integrally provided on the proximal end side of the tube, a pair of wires each having a distal end connected to the ring member, and a pair of wires provided on the proximal end side of the catheter tube And an operating portion for deflecting the distal end portion of the catheter tube, and the tip member is inserted into the coated tube with the ring member and the distal end portion of the catheter tube inserted into the coated tube. Is fixed to the catheter tube by fusing it to the distal end of the catheter tube, Surface of the ring member is characterized by being a rough surface.

  In the tip movable catheter of the present invention, the surface roughness of the surface of the ring member (the surface in contact with the inner surface of the coated tube) can be set to 0.5 μm or more in terms of arithmetic average roughness Ra.

  According to the present invention, since the surface of the ring member to be covered with the covering tube is roughened, even if the distal end portion of the catheter tube is deflected relatively large (for example, up to about 180 °), the covering is performed. It is possible to prevent wrinkles from forming on a part of the inside (the side having a large curvature) of the portion covering the ring surface of the tube. That is, since the surface of the ring member that is covered with the covering tube is a rough surface, relative displacement between the surface of the ring member and the corresponding portion of the inner surface of the covering tube that covers the ring member is prevented. , The compressive force generated on the inside (the side with the large curvature) of the portion covering the ring surface of the coated tube is dispersed as a whole, and the compressive force is concentrated on a part on the inside (the side with the large curvature) of the coated tube To prevent wrinkles.

It is a top view which shows the external appearance structure of the tip movable catheter of embodiment of this invention. It is sectional drawing along the A1-A1 line of FIG. It is sectional drawing along the A2-A2 line of FIG. It is sectional drawing which decomposes | disassembles and shows the front-end | tip part vicinity of the tip movable catheter of embodiment of this invention. It is a top view which shows the front-end | tip part vicinity of the tip movable catheter of embodiment of this invention. It is a perspective view which shows the pull ring of the tip movable catheter of embodiment of this invention. It is a figure which shows generation | occurrence | production of a wrinkle at the time of deflecting the front-end | tip part of the conventional tip movable catheter. It is a figure which shows the experimental result of the relationship between the surface roughness of the pull ring of the tip movable catheter of embodiment of this invention, and generation | occurrence | production of a wrinkle.

  Embodiments of the present invention will be specifically described below with reference to the drawings. The catheter sheath (tip movable sheath) as the tip movable catheter of this embodiment precedes, for example, an electrode catheter for detecting an electrocardiogram or an ablation catheter for cauterizing an affected part when performing catheter ablation. A catheter that is inserted and guides these electrode catheters, ablation catheters, and the like. Hereinafter, a catheter sheath will be described as an example of the distal movable catheter to which the present invention is applied. However, the present invention can also be applied to an electrode catheter, an ablation catheter, and other distal movable catheters.

  Catheter ablation is a treatment method for treating an arrhythmia occurring in the heart. An ablation catheter having a high-frequency electrode at its distal end is passed through a blood vessel to the myocardial tissue causing the arrhythmia in the heart. This is a treatment method that inserts and cauterizes the myocardial tissue or its vicinity at about 60 to 70 ° C. to cause coagulation necrosis, thereby interrupting the arrhythmia circuit.

  First, reference will be made to FIGS. The catheter sheath 1 includes a sheath body 2 as a catheter tube, and an operation portion 3 and a grip portion 4 provided on the proximal end side of the sheath body 2.

  Although the sheath body 2 is formed of a hollow tube and is not shown in the figure, for example, a multilayer tube including a blade layer made of mesh-like stainless steel and a plurality of resin layers is used. A part of the distal end side of the sheath body 2 is a deflecting portion 21 whose direction can be arbitrarily deflected, and the deflecting portion 21 is set to have a lower hardness (flexibly) than the remaining portion, and further deflected. The portion 21 is set so that the hardness decreases gradually or stepwise as it goes to the tip side.

  The proximal end of the sheath body 2 is connected and fixed to a support member 43 provided at the distal end portion of the grip portion 4. An operation unit 3 is provided near the tip of the grip unit 4. The grip portion 4 is formed with an insertion hole 41 communicating with the main lumen 22 which is a hollow portion of the sheath body 2. When the catheter sheath 1 is used (during treatment), the electrode catheter and the ablation catheter described above are attached to the grip portion 4. It is inserted from the insertion hole 41, guided by the main lumen 22, and guided to the myocardial tissue to be treated by each distal end portion.

  In the side wall of the sheath body 2, a pair of sub-lumens 23 a and 23 b that are substantially parallel to the main lumen 22 are formed. The sub-lumens 23a and 23b are formed at positions opposed to each other by 180 degrees, and first and second wires 5a and 5b made of metal such as stainless steel are respectively inserted into the sub-lumens 23a and 23b. ing.

  As shown in FIGS. 4 to 6, a substantially cylindrical pull ring (ring member) 24 made of metal (for example, stainless steel) is disposed on the distal end side of the sheath body 2. A substantially cylindrical tip (chip member) 25 made of resin is disposed on the side. The distal tip 25 has a tip body 25a constituting the distal end portion of the catheter sheath 1 and a thin coated tube 25b formed integrally with a proximal end portion (proximal end portion) of the tip body 25a. . The distal tip 25 is configured such that the pulling tube 24 and the distal end portion (a portion near the distal end) 2a of the sheath body 2 are inserted into the coated tube 25b, while the coated tube 25b is inserted into the distal end portion (a distal end portion) of the sheath body 2. 2a is integrally attached by fusing (for example, heat fusing). The tip body 25a of the distal tip 25 is provided with two side holes 25c so as to be opposed to each other by 180 °, and the lumen of the distal tip 25 is communicated with the outside through the side holes 25c. It has become. By providing the side hole 25c, communication with the outside (inside the blood vessel) in the catheter sheath 1 is ensured even when the hole at the tip of the tip 25 is blocked by abutting against the blood vessel wall. Therefore, the possibility that the inside of the catheter sheath 1 becomes negative pressure and bubbles are generated in the catheter sheath 1 can be reduced.

  Here, the chip body 25a and the covering tube 25b have been described as being integrally formed with each other. However, they may be integrally formed at the same time, or the chip body 25a and the covering tube 25b may be simultaneously formed. Are used as separate members, and the coated tube 25b is set to have a longer dimension in the longitudinal direction. The chip body 25a is inserted into the coated tube 25b from its distal end side, and the coated tube 25b is inserted into the chip body. They may be attached integrally to each other by fusing (for example, heat fusing) to 25a.

  The distal ends of the first wire 5a and the second wire 5b are connected (for example, fixed by welding) to the 180 ° opposing position of the pull ring 24, and the proximal ends of the first wire 5a and the second wire 5b are connected to the sheath body 2. Is connected to the operation unit 3 provided on the base end side. The operation unit 3 is held by a holding unit 42 provided on the front end side of the grip unit 4. A rotation operation member having a pair of protrusions 32 and 33 that can be operated from the outside is rotatably supported in the holding portion 42.

  The proximal ends of the first wire 5a and the second wire 5b are attached to the rotary operation members (32, 33). By rotating the rotation operation members (32, 33) in the direction of arrow B1 in FIG. 1, the first wire 5a is pulled and the second wire 5b is loosened, and the distal end portion of the catheter sheath is in the arrow in FIG. On the contrary, when the rotation operation member (32, 33) is rotated in the direction of arrow B2 in FIG. 1, the first wire 5a is loosened and the second wire 5b is pulled. The distal end portion of the catheter sheath is deflected as indicated by an arrow B4 in FIG.

  By the way, as the pull ring 24, conventionally, a surface whose surface is mirror-finished has been used. However, as shown in FIG. 7, when the distal end portion of the catheter sheath 1 is deflected relatively large (for example, up to about 180 °), as shown in FIG. In some cases, wrinkles (swelling) may occur on a part of the inner side (the side with a large curvature) of the portion covering the surface of the ring (24) of 25b. Or the treatment using the catheter sheath 1 may be hindered, and therefore needs to be prevented.

  Considering the cause of the problem, the covering tube 25b is integrally fixed (fused) to the tip body 25a and the distal end portion 2a of the sheath body 2 with the pull ring 24 interposed therebetween. The pull ring 24 is in close contact with the surface. In this state, when the distal end portion of the catheter sheath 1 is deflected, the portions corresponding to the surface of the pull ring 24 of the coated tube 25b on the inner side (the side with a large curvature) are on both sides (the tip body 25a side and the sheath body). 2 is compressed from the tip 2a side), and the surface of the pull ring 24 is a mirror surface. Therefore, the relative displacement (in relation to the positional relationship between the portion of the covering tube 25b corresponding to the surface of the pull ring 24 and the surface of the pull ring 24) It is considered that wrinkles (swells) S are generated by causing the compression force to concentrate on a part of the portion corresponding to the surface of the pull ring 24 of the coated tube 25b.

  In this embodiment, as best shown in FIG. 6, the surface 24a of the pull ring 24 is made rough so that wrinkles (swells) at the distal end accompanying deflection of the distal end of the catheter sheath 1 occur. The generation is prevented. That is, since the surface 24a of the pull ring 24 is a rough surface, a relative shift (slip) may occur in the positional relationship between the portion corresponding to the surface 24a of the pull ring 24 of the covering tube 25b and the surface 24a of the pull ring 24. It is considered that the generation of wrinkles is prevented because the compressive force that is suppressed and acts on the portion corresponding to the surface 24a of the pull ring 24 of the coated tube 25b is dispersed as a whole. In this embodiment, the surface of the metal pipe is roughened by a small hand grinder equipped with a grindstone with a shaft to obtain the pull ring 24. However, the method of obtaining the rough surface is not limited to this, For example, a rough surface can also be obtained using techniques such as sandblasting, grinding wheel grinding, belt grinding, lapping grinding, chemical etching, and plasma etching.

  When the tip of the catheter sheath 1 is deflected by 180 ° while increasing the surface roughness (arithmetic mean roughness Ra) of the surface of the pull ring 24 (surface on which the coated tube 25b is in contact) 24a stepwise, When the presence or absence of the occurrence of this was confirmed, a result as shown in FIG. 8 was obtained. That is, generation of wrinkles could be prevented by setting the surface roughness of the pull ring 24 to an arithmetic average roughness Ra of about 0.5 μm or more. The upper limit value of the arithmetic average roughness Ra of the surface 24a of the pull ring 24 is not particularly limited, but is preferably up to about 25 μm. The arithmetic average roughness Ra of the surface 24a of the pull ring 24 was measured using a surface roughness / contour shape measuring instrument “Surfcom 2000DX2” manufactured by Tokyo Seimitsu Co., Ltd. The measurement was performed under the measurement conditions of a speed of 0.3 mm / second.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the embodiment described above is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

1. Catheter sheath (tip movable sheath)
2 ... Sheath body 2a ... Sheath body tip 3 ... Operation part 4 ... Grip part 5a ... First wire 5b ... Second wire 21 ... Deflection part 22 ... Main lumens 23a, 23b ... Sub-lumen 24 ... Pull ring 24a ... Pull ring Surface (rough surface)
25 ... Tip (chip member)
25a ... chip body 25b ... coated tube 25c ... side holes 32, 33 ... projection of the rotation operation member

Claims (2)

A catheter tube;
A substantially cylindrical ring member provided on the distal end side of the catheter tube;
A tip member having a substantially cylindrical tip body provided on a further distal end side of the ring member and a covering tube integrally provided on a proximal end side of the tip body;
A pair of wires each having a tip connected to the ring member;
Provided on the proximal end side of the catheter tube, and by operating the pair of wires, the operation unit deflecting the distal end portion of the catheter tube,
The tip member is fixed to the distal end side of the catheter tube by fusing the coated tube to the distal end portion of the catheter tube with the ring member and the distal end portion of the catheter tube inserted into the coated tube. And
A tip movable catheter characterized in that the ring member has a rough surface.   The tip movable catheter according to claim 1, wherein the surface roughness of the surface of the ring member is set to 0.5 μm or more in terms of arithmetic average roughness Ra.

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