JP5459723B2 - Medical guidewire - Google Patents

Description

  The present invention relates to a medical guide wire used as a guide when inserting a catheter into a blood vessel, ureter, organ, or the like, or inserting an indwelling device into a blood vessel aneurysm formation portion.

  In general, the guide wire for medical use is required to have flexibility on the distal end side, and the conventional guide wire 100 is configured such that the outer periphery of the core shaft 101 is covered with a coil spring body 102. In some cases, the front end portion 103 is thinned to improve flexibility (see FIG. 4).

  By the way, when the guide wire 100 is used to guide a device such as a catheter or an indwelling device to a target site in the body, the distal end portion of the guide wire 100 may be unintentionally bent into a U shape. In addition, in order to prevent the invasion of blood vessels other than the intended purpose or to increase the locking force to the blood vessel wall by using the restoring force, a technique for introducing the guide wire 100 by bending it into a U shape in advance is also available. is there.

  Here, in the conventional guide wire 100, since the front-end | tip part 103 of the core shaft 101 is made thin, rigidity is low, and the bending by stress concentration tends to occur. Once the core shaft 101 is bent into a U shape, it is plastically deformed, and a residual angle remains even if the U shape is released. Then, due to this residual angle, the operability of the guide wire 100 thereafter is lowered, and the guide wire 100 may have to be replaced during the operation.

  In addition, the guide wire 100 needs to have a good torque transmission property that transmits a hand operation to the tip portion as well as a flexibility and a restoration property of the tip portion. It is required to ensure both.

  Note that there is a guide wire 100 in which the tip 103 of the core shaft 101 has a stranded structure (see Patent Document 1). Although such a guide wire 100 has a certain degree of resilience from a bent state, when it is bent into a U-shape with a large curvature, it does not recover even if the U-shape is released, and the problem of the residual angle is solved. Was not.

  In addition, there is a guide wire 100 in which a radiopaque inner coil is disposed between a coil spring body 102 and a core shaft 101 (see Patent Documents 2 and 3). In such a guide wire 100, although the rigidity of the distal end portion 103 of the guide wire 100 is improved in a portion where the inner coil is present, the problem of the residual angle after being bent into a U shape has not been solved.

JP 2008-161491 A JP-A-8-173547 JP 2006-511304 Gazette

  The present invention has been made to solve the above-described problems, and an object of the present invention is to improve the resilience of the distal end portion from the U-shaped bend in a medical guide wire and to use the guide wire when using the guide wire. It is to prevent the development of U-shaped bending.

[Means of Claim 1]
A medical guide wire according to claim 1 (hereinafter referred to as a guide wire) includes a core shaft having a small-diameter tip, an outer flexible tube surrounding an outer periphery of the core shaft, and the outer flexible tube as a whole. An inner flexible tube disposed inside the flexible tube and enclosing the tip of the core shaft, a tip of the core shaft, a tip of the outer flexible tube, and a tip of the inner flexible tube The inner flexible tube has a tapered shape in which the outer diameter gradually decreases toward the tip, and the inner diameter is the tip. From the rear to the rear end .

[Means of claim 2]
The guide wire according to claim 2, wherein a core shaft having a small-diameter tip, an outer flexible tube surrounding an outer periphery of the core shaft, and the whole are disposed inside the outer flexible tube, An inner flexible tube surrounding the tip of the core shaft; a tip of the core shaft; a tip of the outer flexible tube; and a tip brazing portion that joins the tip of the inner flexible tube. In the medical guide wire, the inner flexible tube has an outer diameter that gradually decreases toward the tip, and an inner diameter that is constant from the tip to the rear end .

[Means of claim 3]
The guidewire of claim 3, in the guide wire according to claim 1 or 2, further comprising a stranded wire that is disposed parallel to the distal end portion of the core shaft inside the pre-Symbol inner flexible tube Features.

[Means of claim 4 ]
A guide wire according to a fourth aspect of the present invention is the guide wire according to any one of the first to third aspects, wherein the outer flexible tubular body is a single coil and is predetermined from the tip of the outer flexible tubular body. In the distance range, a pitch expansion portion having a single coil pitch wider than the rear end portion of the outer flexible tubular body is provided, and the rear end of the pitch enlarged portion is the front end than the rear end of the inner flexible tubular body. It is arranged on the side.

(Example 1) which is a side view (a partial sectional view is included) of a guide wire. (Example 1) which is side sectional drawing of the front-end | tip part of a guide wire. It is a partial side view of a core shaft (modification). It is side part sectional drawing of a guide wire front-end | tip part (conventional example).

The guide wire of the best mode 1 includes a core shaft having a small-diameter tip, an outer flexible tube surrounding the outer periphery of the core shaft, a stranded wire arranged in parallel to the tip of the core shaft, A multi-strand hollow stranded coil surrounding the tip of the core shaft and the stranded wire is provided inside the flexible tube.
The ends of the hollow stranded coil, the core shaft, and the stranded wire are joined to the tip of the outer flexible tubular body.

Further, the outer diameter of the core shaft is gradually reduced toward the tip.
The hollow stranded wire coil is a multi-wire hollow stranded wire coil formed by twisting a plurality of metal strands, and has a tapered shape in which the outer diameter gradually decreases toward the tip. The hollow stranded coil has a constant inner diameter from the front end to the rear end. Moreover, the metal strand which forms a hollow strand wire coil is formed with the stainless alloy.

[Configuration of Example 1]
The structure of the guide wire 1 of Example 1 is demonstrated using FIG. 1, FIG. 1 and 2, the right side is the front end side, and the left side is the rear end side.
The guide wire 1 includes a core shaft 2, a stranded wire 3 arranged in parallel with the core shaft 2, an outer flexible tube 4 through which the core shaft 2 and the stranded wire 3 are inserted, and an outer flexible tube 4. The hollow stranded wire coil 5 is provided inside, the core shaft 2 and the stranded wire 3 are inserted into the hollow stranded wire coil 5, and these are further inserted into the outer flexible tube 4.

  The core shaft 2 is formed of a stainless alloy, and has a large-diameter grip portion 21 on the rear end side and a small-diameter tip portion 22 on the front end side. The tip portion 22 of the core shaft 2 is narrowed in stages, and has a small-diameter portion 25 that is reduced in diameter via a step portion 23. In the present embodiment, for example, the outer diameter of the small diameter portion 25 is 0.03 mm.

The stranded wire 3 is formed by twisting metal strands such as a plurality of stainless steel wires. In this embodiment, for example, seven stainless steel wires having an outer diameter of 0.014 mm are twisted.
The stranded wire 3 is arranged in parallel with the distal end portion 22 of the core shaft 2, and the distal end of the stranded wire 3 is connected to the distal end of the distal end of the outer flexible tubular body 4 together with the distal end of the core shaft 2 and the hollow stranded wire coil 5 described later. Soldered to the attaching portion 41, the rear end of the stranded wire 3 is located on the rear end side of the rear end of the small diameter portion 25 of the core shaft 2, and the rear end portion of the stranded wire 3 is On the rear end side, it is soldered to the hollow stranded coil 5 together with the core shaft 2 (soldering portion 7).

  The outer flexible tubular body 4 is a single coil formed of a stainless steel wire. In this embodiment, for example, the outer flexible tube 4 is formed of a stainless steel wire having an outer diameter of 0.05 mm and an outer diameter of the single coil of 0.355 mm. . Further, the outer flexible tube 4 has a coil pitch widened only at the distal end side in order to give more flexibility to the distal end side. The outer flexible tube 4 is not limited to a single coil as long as it has flexibility, and may be a hollow stranded coil, a resin tube, or the like.

  The outer flexible tube 4 is covered only on the front end side of the core shaft 2, and the rear end 42 of the outer flexible tube 4 is fixed to the outer peripheral surface of the large-diameter portion on the rear end side of the core shaft 2. Further, a hydrophilic resin coating is applied to the outer peripheral surface of the outer flexible tubular body 4.

The hollow stranded wire coil 5 is formed by twisting a plurality of stainless steel strands into a rope shape using a rope twisting machine and removing the central member, or by twisting a plurality of strands into a hollow shape. It has a form. In this embodiment, for example, six stainless steel wires having an outer diameter of 0.04 mm are twisted to form an outer diameter of 0.188 mm in order to improve the balance between flexibility and torque transmission.
Moreover, the front-end | tip part 52 of the hollow stranded coil 5 is processed by the taper shape which an outer diameter becomes small toward an end by electropolishing. The inner diameter of the hollow stranded coil 5 is constant from the rear end to the front end.

  The hollow stranded coil 5 is formed to have an outer diameter smaller than the inner diameter of the outer flexible tube 4, and the axial length is smaller than that of the outer flexible tube 4. The end 53 is located on the front end side with respect to the rear end 42 of the outer flexible tubular body 4. The hollow stranded coil 5 and the outer flexible tubular body 4 are fixed at least at one place in order to fix their relative positions. In this embodiment, the hollow stranded wire coil 5, the outer flexible tubular body 4, the stranded wire 3, and the core shaft 2 are fixed by soldering at the position of the step portion 23 (soldering portion 8). Further, the hollow stranded coil 5 and the outer flexible tubular body 4 are fixed to each other on the rear end side from the rear end position of the stranded wire 3 in the axial direction (soldering portion 9).

  Further, in the relationship between the core shaft 2 and the stranded wire 3, the rear end 53 of the hollow stranded wire coil 5 is located on the rear end side with respect to the step portion 23 of the core shaft 2 and on the rear end side with respect to the rear end of the stranded wire 3. To do. As described above, the tip of the hollow stranded coil 5 is fixed to the tip brazing portion 41 at the tip of the outer flexible tubular body 4 together with the tips of the core shaft 2 and the stranded wire 3, The end 53 is fixed to the outer peripheral surface of the core shaft 2.

[Effects of Example 1]
In the guide wire 1 of the present embodiment, the stranded wire 3 is arranged in parallel with the distal end portion 22 of the core shaft 2. And the front-end | tip part 22 of the core shaft 2 is thinned in steps toward the front-end | tip. Here, since the stranded wire 3 can move relatively minutely between the strands, it has a degree of freedom, high flexibility, hardly plastic deformation, and high resilience. For this reason, by providing a twisted wire that is difficult to be plastically deformed in parallel with the distal end portion 22 of the core shaft 2 having a small diameter for ensuring flexibility, the guidewire 1 is restored from being bent while ensuring flexibility. Improves.

  Further, the guide wire 1 includes a hollow stranded wire coil 5 that surrounds the distal end portion 22 of the core shaft 2 and the stranded wire 3 inside the outer flexible tubular body 4, and the hollow stranded wire coil 5 includes the core shaft 2 and the stranded wire. 3 and the distal end of the outer flexible tubular body 4 are joined together. Since the multi-wire hollow stranded coil 5 has better torque transmission than a single coil, the distal end of the guide wire 1 is joined by joining the distal end of the hollow stranded coil 5 to the distal end of the outer flexible tubular body 4. By arranging in, the operation on the hand side can be smoothly transmitted to the tip side. For this reason, since a guide wire can be operated according to a user's aim, treatment time can be shortened. Moreover, since this hollow stranded wire coil 5 is excellent also in the recoverability compared with a single coil, by enclosing the outer periphery of the core shaft 2 and the stranded wire 3, the recoverability of the front-end | tip part of the guide wire 1 is improved. be able to.

  Moreover, since the front-end | tip part 52 of the hollow stranded coil 5 is formed in the taper shape which becomes thin gradually toward the front-end | tip, the rigidity gradual change structure from which the guide wire 1 becomes gradually rigid toward the rear end side. Thus, the occurrence of stress concentration due to a sudden change in rigidity can be further reduced, and torque transmission is improved. Moreover, by making the diameter of the distal end side of the hollow stranded coil 5 thinner, the flexibility of the guide wire 1 is improved, and the insertion property into the lumen peripheral portion is improved.

  Further, since the inner diameter of the hollow stranded wire coil 5 is constant from the front end to the rear end, it becomes easy to insert the core shaft 2 and the stranded wire 3 into the hollow stranded wire coil 5 and to easily assemble the preferred guide wire 1. can do.

  Moreover, since the metal strand which forms the hollow strand wire coil 5 is formed with the stainless steel alloy, the rigidity of the hollow strand wire coil 5 can be improved, and the torque transmission property and operability of the guide wire 1 are improved. be able to.

[Modification]
In Example 1, although the front-end | tip part 22 of the core shaft 2 became thin in steps toward the front-end | tip, you may make it thin in a taper shape toward a front-end | tip.

  In Example 1, the core shaft 2 is made of a stainless alloy, but the tip portion (at least the small diameter portion 25) of the core shaft 2 is made of a pseudoelastic alloy (for example, a Ni—Ti alloy) having excellent resilience. It may be formed and the rear end side may be formed of a stainless alloy. According to this, the resilience of the distal end portion of the guide wire 1 can be improved, and the torque transmission performance and operability can be improved.

  Further, as shown in FIG. 3, the tip portion of the small diameter portion 25 is formed of a stainless alloy (first tip portion 26), and the rear end portion of the small diameter portion 25 is formed of a pseudoelastic alloy (second tip portion). 27) The core shaft 2 on the rear end side of the small diameter portion 25 may be formed of a stainless alloy. According to this, the restoring property of the front-end | tip part 22 of the core shaft 2 can be improved with a pseudoelastic alloy. In addition, by providing a portion formed of a stainless alloy on both the front end side and the rear end side of the portion formed of the pseudoelastic alloy (second front end portion 27), the torque on the rear end side can be reliably transferred to the front end side. Thus, torque transmission and operability can be further improved.

  Moreover, in Example 1, although the front-end | tip part 52 of the hollow stranded wire coil 5 was taper-shaped toward the front-end | tip, you may make it thin in steps toward a front-end | tip.

  Moreover, in Example 1, although the hollow stranded coil 5 was formed only with the stainless steel strand, you may form only with a pseudoelastic alloy strand. According to this, the restoring property of the hollow stranded coil 5 can be further enhanced. Further, the hollow stranded coil 5 may be formed by combining a stainless steel wire and a pseudoelastic alloy wire (for example, a combination of three stainless steel wires and three pseudoelastic alloy wires). According to this, the rigidity of the hollow stranded coil 5 can be increased with the stainless steel wire, and the resilience of the hollow stranded coil 5 can be increased with the pseudoelastic alloy strand. For this reason, the torque transmission property, operability, and restoring property of the guide wire 1 can be improved.

  The guide wire 1 according to the first embodiment has a structure in which the outer flexible tube 4 surrounds only the distal end side of the core shaft 2. May be.

DESCRIPTION OF SYMBOLS 1 Guide wire 2 Core shaft 22 Core shaft tip 26 First tip 27 Second tip 3 Strand 4 Outer flexible tube 5 Hollow strand coil

Claims (4)

A core shaft having a narrow tip, and
An outer flexible tube surrounding the outer periphery of the core shaft;
An inner flexible tube that is disposed entirely inside the outer flexible tube and surrounds the tip of the core shaft;
A medical guide wire comprising a tip end of the core shaft, a tip end of the outer flexible tube body, and a tip brazing portion that joins the tip end of the inner flexible tube body,
A medical guide wire, wherein the inner flexible tube has a tapered shape in which an outer diameter gradually decreases toward a distal end, and an inner diameter is constant from the distal end to the rear end . A core shaft having a narrow tip, and
An outer flexible tube surrounding the outer periphery of the core shaft;
An inner flexible tube that is disposed entirely inside the outer flexible tube and surrounds the tip of the core shaft;
A medical guide wire comprising a tip end of the core shaft, a tip end of the outer flexible tube body, and a tip brazing portion that joins the tip end of the inner flexible tube body,
A medical guide wire characterized in that the inner flexible tube has an outer diameter that gradually decreases toward the tip, and an inner diameter that is constant from the tip to the rear end . Ya. The medical guidewire according to claim 1 or 2 ,
A medical guide wire comprising a stranded wire arranged in parallel with the tip of the core shaft inside the inner flexible tube. In the medical guidewire according to any one of claims 1 to 3 ,
The outer flexible tubular body is a single coil, and a pitch expanding portion in which the pitch of the single coil is wider than the rear end portion of the outer flexible tubular body in a predetermined distance range from the tip of the outer flexible tubular body. The medical guide wire is characterized in that a rear end of the pitch expanding portion is arranged on a front end side with respect to a rear end of the inner flexible tubular body.

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