JPH0623543U - Medical guidewire - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a medical guide wire that is hard to bend, has excellent hand-transmittability, particularly rotation-transmittance, and has excellent flexibility at the distal end. [Structure] The core wire 12 is composed of a stranded wire made of at least three or more thin metal wires having a diameter of 0.01 to 1.2 mm, and a tip portion 12a thereof is formed in a tapered shape. A metal braze 1 is prepared by screwing a base end 16a and a tip 16b of a shape memory alloy coil 16 having an outer diameter of 0.1 to 3 mm and a stainless steel coil 17 into the portion.
By brazing with 8, the tip portion 12a of the core wire 12
Stick to. The tip 16b of the coil 16 has a metal braze 18
To form a round head portion 19, and the tip end of the core wire 12 is fixed thereto.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a medical guide wire used for inserting a catheter into, for example, a blood vessel, a ureter, a bile duct, a trachea, or the like.

[0002]

[Prior art]

 In recent years, for inspection and treatment of human tubular organs such as blood vessels, ureters, bile ducts, and trachea, a catheter is inserted to administer a drug such as a contrast agent, or a part of the tissue is collected with forceps etc. through the catheter. Things are being done. When inserting a catheter, a relatively thin and flexible guide wire is first inserted into the tubular organ, the catheter is inserted along the outer circumference of the guide wire, and then the guide wire is extracted.

Examples of the guide wire include (1) a core wire made of stainless steel, shape memory alloy, or the like, which has a tapered tip end and a synthetic resin film coated on the outer periphery, and (2) a relatively thick core wire. (3) Inserting a safety wire and an inner core wire into the inside of the tightly wound coil, and fixing their ends to the coil. Various things have been proposed.

FIG. 5 shows an example of the guide wire of (2) above. That is, in this guide wire 41, a coil 45 formed by closely winding a fine wire is welded and attached to the tip of a taper wire 43 having a tapered tip. The tip portion of the coil 45 is a melted and rounded head portion 47, which is designed so as not to damage the inside of a blood vessel or the like. A safety wire 49 is arranged inside the coil 45, and a tip end portion 49 a thereof is fixed to the head portion 47 and a base end portion 49 b thereof is fixed to the tip end portion 43 a of the taper wire 43 by welding.

Further, FIG. 6 shows an example corresponding to the guide wire of the above (1) disclosed in JP-A-64-62175. The guide wire 51 includes a metal inner core portion 53 formed by twisting a plurality of thin metal wires together, and a synthetic resin covering portion 55 that encloses the metal inner core portion 53. The tip portion 53a of the metallic inner core portion 53 is formed in a tapered shape, and imparts flexibility to the tip portion. A tip 57 made of an X-ray impermeable metal such as tungsten is installed in the synthetic resin covering portion 55 at the tip of the guide wire 51, and the position of the tip of the guide wire 51 inserted into the body is set. It can be confirmed on the X-ray TV monitor.

[0006]

[Problems to be solved by the device]

 Since such a guide wire is inserted into a curved path such as a blood vessel, its distal end needs to have sufficient flexibility so as not to damage the tissue, and the operation at hand is transmitted to the base side. So some rigidity is required. Also, at the bifurcated or curved location of the blood vessel, etc., it is necessary to direct the distal end of the guide wire in the desired direction and guide it correctly in the traveling direction.In this case, rotate the guide wire in the prescribed direction at the proximal part. Thus, the tip of the guide wire is directed in a desired direction. For this reason, the guide wire is also required to have rotation transmissibility to transmit the rotational force at hand to the distal end portion.

However, in the guide wire 41 shown in FIG. 5, since the base side is made of one taper wire 43, there is a tendency that the rigidity becomes too strong if the guide wire 41 is made thicker in order to improve the rotation transmissibility. If it is thinned to weaken the rigidity, there is a problem that rotation transmission cannot be obtained sufficiently. Further, the guide wire 41 has a problem that bending (kink) is likely to occur at the tapered wire 43. Furthermore, since the coil 45 is fixed by welding (brazing), a shape memory alloy having poor wettability with respect to the metal brazing cannot be used.

Further, in the guide wire 51 shown in FIG. 6, the tip end portion 53a of the metal inner core portion 53 is tapered to provide flexibility, but the degree of flexibility greatly changes depending on the precision of the taper processing. Therefore, the adjustment was difficult. In addition, since the distal end of the guide wire 51 is a portion of only the synthetic resin covering portion 55 without the metal inner core portion 53, for example, the tip of the guide wire 51 is guided to one of the branched blood vessels. At that time, it was not possible to bend in a predetermined direction beforehand.

Therefore, an object of the present invention is to provide a medical guide wire which is less likely to be bent (kink), has excellent transmissibility of hand operation, particularly rotational transmissibility, and has excellent flexibility of the distal end portion. Especially.

[0010]

[Means for Solving the Problems]

 To achieve the above object, a medical guide wire according to the present invention comprises a core wire formed by tapering the ends of a stranded wire made of at least three or more metal fine wires having a diameter of 0.01 to 1.2 mm. A shape memory alloy coil having an outer diameter of 0.1 to 3 mm fixed to the outer circumference of the tapered portion of the core wire is provided.

In a preferred aspect of the present invention, a metal having good brazing property is screwed into both ends of the shape memory alloy coil, and together with this metal, both ends of the shape memory alloy coil are brazed to the core wire. It is attached.

[0012]

[Action]

 The medical guide wire according to the present invention is less likely to bend (kink) due to the twisted core wire.Since the twisted wire has unevenness on the outer circumference, the contact area with the inner wall of the catheter is reduced, The advantage is that the slidability is good and the stranded wire has excellent rotation transmission properties.

Further, by fixing the shape memory alloy coil to the tip of the core wire, excellent flexibility due to the superelasticity of the shape memory alloy can be obtained. Shape memory alloys pass X-rays more than ordinary metals. Since it is difficult, the position of the tip of the guide wire can be confirmed through an X-ray TV monitor without using a material such as platinum.

[0014]

【Example】

 1 to 3 show an embodiment of a guide wire according to the present invention, FIG. 1 is a sectional view of a main part of a guide wire, FIG. 2 is a partially enlarged sectional view showing a brazed portion on a coil base side, and FIG. It is a partial expanded sectional view which shows the brazing part by the side of a coil.

As shown in FIG. 1, the guide wire 11 has a core wire 12 made of a stranded wire having a tapered distal end 12a. The core wire 12 is made of an elastic metal such as stainless steel or piano wire, and is made by joining at least three or more thin wires having a diameter of 0.01 to 1.2 mm, and the tip end of the obtained twisted wire is gradually immersed in, for example, an etching solution. It can be manufactured by processing into a taper shape by a method such as etching while pulling it up or mechanically stretching so as to obtain a desired thickness.

As the stranded wire constituting the core wire 12, as shown in FIG. 4 (a), three thin wires 13 of the same thickness are twisted together, and as shown in FIG. 4 (b), Various structures such as a comparatively thick line 14 provided at the center and a plurality of fine lines 15 provided around the relatively thick line 14 can be adopted.

A coil 16 formed by closely winding a shape-memory alloy thin wire is arranged around the tip portion 12 a of the core wire 12. The outer diameter of the coil 16 is 0.1 to 3 mm. The outer diameter of the core wire 12 is preferably equal to or slightly smaller than that of the coil 16. Although the length of the coil 16 is not particularly limited, it is usually preferably 30 to 500 mm. As the shape memory alloy, Ti-Ni alloy, Cu-Zn-Al alloy and the like are preferably used.

As shown in FIG. 2, a stainless steel coil 17 is screwed between the pitches of the base ends 16 a of the coils 16, and the whole of the portion is brazed with a metal braze 18. Similarly, as shown in FIG. 3, the stainless coil 17 is also screwed in between the pitches of the tips 16b of the coils 16, and the whole of the portion is brazed with a metal braze 18. In this case, the metal brazing material 18 forms a head portion 19 that closes the tip end portion 16b of the coil 16 in a hemispherical shape, and fixes the tip end portion 12a of the core wire 12 together. In this way, by screwing the stainless steel coil 17 into the end of the shape memory alloy coil 16 and brazing it, even a shape memory alloy coil having poor wettability with respect to the metal brazing can be welded to the core wire 12. It has become possible. The length of the brazed portion (the length into which the stainless coil 17 is screwed in) is preferably at least 1 mm or more. The head portion 19 also serves to prevent damage to the inner wall of the guide wire when the guide wire is inserted into a blood vessel or the like.

As shown in FIG. 1, the outer circumference of the core wire 12 may be covered with a synthetic resin film (or a synthetic resin tube) 20 such as a fluororesin. Furthermore, the surface of the synthetic resin film 20 may be coated with a hydrophilic polymer. Examples of such a hydrophilic polymer include the resins disclosed in Japanese Patent Publication No. 14991/1991. However, in the present invention, a twisted wire is used as the core wire 12, and in the case of the twisted wire, the contact area with the inner wall of the catheter is small, so it is sufficient to form a resin film with good slipperiness such as fluororesin. It is possible to obtain excellent slipperiness.

In the thus-obtained guide wire 11, the core wire 12 is made of a stranded wire, and therefore bending is less likely to occur even when it is strongly bent, and the rotation transmissibility is superior to that of a single wire. Further, since the tip end portion 12a of the core wire 12 is formed in a tapered shape and passed through the coil 16 and fixed to the head portion 19 at the tip end of the coil 16, the tip end portion 12a of the core wire 12 regulates the elongation of the coil 16. Acts as a safety wire. The shape memory alloy coil 16 at the tip of the guide wire 11 exhibits excellent flexibility due to the superelasticity which is a characteristic of the shape memory alloy. Further, since the shape memory alloy 16 is more excellent in X-ray opacity than ordinary metal, it becomes easy to confirm the position through the X-ray TV monitor.

[0021]

[Effect of device]

 As described above, according to the present invention, since the core wire is composed of the stranded wire, it is possible to provide a guide wire that is unlikely to be bent, has good slidability with respect to the inner wall of the catheter, and has good rotation transmission properties. Further, since the tip portion is made of the shape memory alloy coil, more excellent flexibility can be obtained and the position can be easily confirmed through the X-ray TV monitor.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of a guide wire according to the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing a brazing portion on the base side of the shape memory alloy coil of the guide wire.

FIG. 3 is a partially enlarged cross-sectional view showing a brazing portion on the tip side of the shape memory alloy coil of the guide wire.

FIG. 4 is a sectional view showing a structure of a core wire of a guide wire according to the present invention.

FIG. 5 is a cross-sectional view of an essential part showing an example of a conventional guide wire.

FIG. 6 is a cross-sectional view showing another example of a conventional guide wire.

[Explanation of symbols]

 11 Guide wire 12 Core wire 12a Tip part 13 Fine wire 16 Shape memory alloy coil 17 Stainless steel coil 18 Metal brazing 19 Head 20 Synthetic resin film

Claims (2)

[Scope of utility model registration request] 1. A core wire formed by tapering an end portion of a stranded wire made of at least three or more thin metal wires having a diameter of 0.01 to 1.2 mm, and an outer diameter fixed to the outer circumference of the tapered portion of the core wire. 0.1 to 3
A medical guide wire comprising a mm shape memory alloy coil. 2. A metal having good brazing property is screwed into both ends of the shape memory alloy coil, and both ends of the shape memory alloy coil are brazed to the core wire together with the metal. The medical guide wire according to 1.