JP2006263083A - Medical guide wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a medical guide wire whose distal end part has superior deformability, proximal end part continuing from the distal end part has a superior torque transmission property, and distal end part and proximal end part are joined together at high strength. <P>SOLUTION: This medical guide wire is provided with a distal end side member 11 formed of a metal wire rod having the superior deformability and a proximal end side member 12 formed of a metal wire rod having the superior torque transmission property, and the proximal end side end face 11a of the distal end side member 11 and the distal end side end face 12a of the proximal end side member 12 are joined together as the joining end faces. An interval between the respective joining end faces 11a and 12a of the distal end side member and the proximal end side member is provided with a clearance 14 allowing the intrusion of a brazing material, an interval between a connecting member 16 covering the outer circumferential face of the joining part 15 between the distal end side member 11 and the proximal end side member 12, and the outer circumferential face of the joining part 15 is provided with a clearance 17 allowing the intrusion of the brazing material, the both clearances 14 and 17 are filled with the brazing material 13 to join the distal end side member 11 with the proximal end side member 12, and the connecting member 16 covers the outer circumference of the joining part 15 and the outer circumference of a part of the distal end side member 11 continuing from the joining part 15. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a medical guide wire used for guiding a thin tubular catheter introduced into a blood vessel, a digestive tract, a trachea, or other body cavity (hereinafter referred to as “treatment tube”) requiring treatment or examination. Hereinafter, the present invention also relates to a medical guide wire having a distal end portion and a proximal end portion made of metal wires having different performances.

  When a catheter is introduced into a treatment tube of a human body that requires treatment or examination, a medical guide wire is introduced to a required site prior to introduction of the catheter. An important performance as a medical guide wire is that it can be smoothly inserted into a treatment-needed tube by hand operation, and the catheter can be guided and introduced accurately to the target site. For this reason, the medical guide wire has a form conformability that can be inserted into a treatment-needed tube whose tip portion is meandering in a complicated manner without damaging the inner wall of the treatment-needed tube. The end portion is required to have a torque transmission property that accurately transmits torque to the tip portion even with a slight operation amount at hand.

  There are various types of medical guidewires depending on the application. For example, as shown in FIG. 7, a structure in which a core material 50 having a predetermined length is covered with a synthetic resin 51 is known. In the core member 50, in order to give flexibility to an insertion portion as a guide wire, the distal end portion 52 is formed in a tapered shape whose cross-sectional area gradually decreases toward the distal end.

  Conventionally, a stainless steel wire or a piano wire has been used as the core material. However, the guide wire using this type of core material has a problem that it is difficult to apply to a branching blood vessel or the like that meanders in a complicated manner even if the tip portion is tapered.

  Therefore, a guide wire using a Ni—Ti alloy, which is a superelastic alloy, as a core material has been proposed. The core material made of superelastic alloy is flexible and has resilience to deformation up to a considerable range (approximately 8% strain). Therefore, it is difficult to bend during hand operation and difficult to bend. Although the core material is made of a single superelastic material, it has sufficient shape adaptability as a whole, but its transmittable torque and torsional rigidity are comparable to stainless steel wire or piano wire. Therefore, there is a difficulty in torque transmission at the base end.

  Thus, it is difficult to satisfy the form adaptability and torque transmission required for the guide wire with one kind of material. Therefore, as shown in FIG. 8, in Patent Document 1, the distal end side member and the proximal end side member of the guide wire are made of different materials, and the distal end side member formed from a metal wire having good form adaptability and torque It has been proposed to join a proximal end member formed of a metal wire having excellent transmission properties to form one guide wire.

A conventional guide wire 1 shown in FIG. 8 includes a first wire 2 (distal end side member) and a second wire 3 (proximal end side member) made of different materials, and is formed in the small diameter portion 4 of the first wire 2. The second notch portion 5 and the second notch portion 7 formed in the narrow diameter portion 6 of the second wire 3 are arranged so as to overlap each other, and the tubular connecting member 8 covers the outer periphery of the overlapping portion. And a gap between the outer peripheral surface of the small diameter portion 4 of the first wire 2 and the small diameter portion 6 of the second wire 3 and the inner peripheral surface of the tubular connecting member 8 is filled with the brazing material 9. 1 wire 2 and 2nd wire 3 are joined.
JP 2004-16359 A

  As shown in the guide wire shown in FIG. 8, the distal end side (insertion side) and the proximal end side (operation side) are made of different members, and the distal end side member is formed from a metal wire with good form adaptability, and torque transmission. When a proximal end member formed of a metal wire having excellent properties is joined to form a single guide wire, it is possible to obtain a guide wire having form conformability and torque transmission. However, in the case where the guide wire is joined by two kinds of members in this way, in the guide wire 1 shown in FIG. 8, the first connecting wire 2 and the second connecting wire 3 are arranged on the outer periphery of the joining portion. 8, the length of the tubular connecting member 8 is short because only the brazing material 9 filled in the gaps between the inner peripheral surface of the first wire 2 and the outer peripheral surfaces of the first wire 2 and the second wire 3 is joined. And the bonding strength is insufficient. Therefore, it is necessary to increase the length of the tubular connecting member 8 in order to ensure a predetermined bonding strength, but if the length of the tubular connecting member 8 is increased, the heating time for filling the gap with the brazing material 9 is increased. As a result, the first wire 2 and the second wire 3 are affected by heat on both sides of the tubular connecting member 8 to change the metal characteristics thereof, and the shape adaptability and torque transmission performance of the guide wire are impaired. There is a risk of being lost.

  In addition, due to the rapid advancement of medical technology in recent years, the medical guidewire has a conformability at the distal end and a torque transmission at the proximal end so that it can be applied to complex branch vessels. There is a need to further improve the above. Further, the guide wire tip is required to be further reduced in diameter, and as the diameter decreases, handling becomes complicated and the entire assembly operation becomes difficult. As a result, it may be difficult to obtain a sufficient bonding strength between the distal end portion and the proximal end portion, or variation in bonding strength between products may increase.

  The present invention has been made in view of such problems of the prior art, and its purpose is that the distal end portion is excellent in form adaptability, and the proximal end portion following the distal end portion is excellent in torque transmission, An object of the present invention is to provide a medical guide wire having high bonding strength between a distal end portion and a proximal end portion.

  In order to achieve the above object, a medical guide wire of the present invention includes a distal end member formed from a metal wire having good form adaptability, and a proximal end member formed from a metal wire excellent in torque transmission. In the medical guide wire formed by joining the two members with the proximal end surface of the distal end member and the distal end surface of the proximal end member as the joining end surfaces, the joining end surface of the distal end member and the proximal end member A gap through which the brazing material can enter is provided between the connecting member covering the joint outer peripheral surface of the distal end side member and the base end side member and the joint outer peripheral surface. The distal end side member and the proximal end side member are joined by filling the gap with the brazing material, and the connection member covers the outer periphery of the joint portion and the outer periphery of a part of the distal end side member following the joint portion. It is characterized by that.

  In this way, a gap (first gap) through which the brazing material can enter is provided between the joint end surfaces of the distal end side member and the proximal end side member, and the joint outer peripheral surface of the distal end side member and the proximal end side member is provided. A gap (second gap) into which the brazing material can enter is provided between the connecting member to be covered and the outer peripheral surface of the joint portion, and the first gap and the second gap are filled with the brazing material, Since the base end side member is joined, the brazing material is not only a gap (second gap) between the joint portion outer peripheral surface of the front end side member and the base end side member and the inner peripheral surface of the connection member, The gap (first gap) between the joining end surfaces of the distal end side member and the proximal end side member is also filled, and the distal end side member and the proximal end side member are brazed between the end surfaces and the inner peripheral surface of the connecting member. In addition, since the entire surface of the distal end side member and the proximal end side member in the connection member becomes the joint portion, the medical guide having high joint strength between the distal end portion and the proximal end portion It is possible to provide a wire.

  Furthermore, since the connecting member covers the outer periphery of the joint portion and the outer periphery of a part of the tip side member following the joint portion, it is possible to accurately transmit a delicate operation at hand to the tip portion. That is, since the distal end side member is formed of a metal wire having good form adaptability, the rigidity is slightly lower than that of the proximal end side member. Therefore, the distal end side member may not be smoothly inserted into the treatment-needed tube corresponding to the operation of the proximal end side member. However, since the connecting member covers the outer periphery of the joint portion and the outer periphery of a part of the distal end side member following the joint portion, the change in rigidity from the proximal end side member to the distal end side member becomes smooth, and at the proximal end portion It is possible to accurately transmit the hand operation to the distal end portion, and to arbitrarily insert the distal end portion that is flexible and has excellent form adaptability into the treatment requiring tube.

  It is preferable that the joining end surface is an inclined surface inclined with respect to the axes of the distal end side member and the proximal end side member. This is because the area of each joining end surface of the distal end side member and the proximal end side member can be increased, and the joining strength can be improved.

  The joint end face and the joint outer peripheral surface are preferably pre-plated with Ni before filling with the brazing material. This is because the adhesion strength of the joining surface by the brazing material can be improved.

  Further, it has a distal end side member formed from a metal wire having good form adaptability and a proximal end member formed from a metal wire excellent in torque transmission. In a medical guide wire formed by joining both members with the distal end surface of the end member as a joining end surface, a long hole through which a core material can be inserted is formed on the joining end surface of the distal end member and the proximal end member. And in the axial direction of the base end side member, a gap into which the brazing material can enter is provided between the joint end surfaces of the tip end side member and the base end side member, a core material is inserted into the long hole, and the joint end surface It is preferable that the distal end side member and the proximal end side member are joined to each other by filling a brazing material. The brazing material is filled not only in the gap between the joining end surfaces of the distal end side member and the proximal end member, but also in the gap between the core material, the distal end side member and the proximal end member, and the distal end side member and the proximal end side member are filled. Is brazed between the end surfaces and the outer peripheral surface of the core material, and the bonding area between the distal end side member and the proximal end side member can be increased, so that the medical guide having a high bonding strength between the distal end portion and the proximal end portion. A wire can be provided. In addition, since there is no projection such as a connecting member that covers the outer periphery of the joint, it is possible to more smoothly insert the distal end portion that is flexible and excellent in form adaptability into the treatment-needed tube.

  The joint end face and the long hole inner face are preferably pre-plated with Ni before filling with the brazing material. This is because the adhesion strength of the joining surface by the brazing material can be improved.

Since the medical guide wire of the present invention is configured as described above, the following effects can be obtained.
(1) According to the first aspect of the present invention, since the entire surface of the distal end side member and the proximal end side member in the connection member becomes a joint portion, a medical guide wire having a high joint strength between the distal end portion and the proximal end portion is provided. Since the connecting member covers the outer periphery of the joint portion and the outer periphery of a part of the distal end side member following the joint portion, the change in rigidity from the base end side member to the distal end side member becomes smooth, The hand operation at the proximal end portion can be accurately transmitted to the distal end portion, and the distal end portion that is flexible and excellent in form adaptability can be arbitrarily inserted into the treatment-needed tube.
(2) According to invention of Claim 2, the area of each joining end surface of a front end side member and a base end side member can be increased, and joining strength can be improved.
(3) According to the inventions of claims 3 and 5, the adhesion strength of the joint surface by the brazing material can be improved.
(4) According to the invention described in claim 4, since the joining area between the distal end side member and the proximal end side member can be increased, a medical guide wire having a high joining strength between the distal end portion and the proximal end portion is provided. In addition, since there is no connection member that covers the outer periphery of the joint portion, it is possible to more smoothly insert the distal end portion that is flexible and excellent in form adaptability into the treatment-needed tube.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  Examples of the metal wire having good form adaptability include, but are not limited to, a Ni—Ti alloy, a Cu—Al—Ni alloy, a Cu—Zn—Al alloy, and the like.

  Although it does not limit as a metal wire material excellent in torque transmissibility, For example, stainless steel, a piano wire, etc. can be used. Among these, high silicon stainless steel can be preferably used. When the composition of this high silicon stainless steel is expressed by weight%, C = 0.08% or less, Si = 3.0-5.0%, Mn = 3.0% or less, Ni = 4.0-12. Use 0%, Cr = 12.0 to 24.0%, Mo = 0.9 to 2.0%, Cu = 0.5 to 2.0%, the balance being iron and inevitable impurities Can do. This high silicon stainless steel is a material having high tensile strength and impact value and high toughness, and is preferable as a material for a base end portion that requires excellent torability. This high silicon stainless steel is a precipitation hardening type stainless steel, and its high toughness depends on the action of silicon, and in order to give sufficient toughness, it is necessary to contain 3% or more of silicon. However, not only is the content of carbon unnecessary, but if the content increases and exceeds 0.08%, the toughness decreases. Further, even if silicon exceeds 5%, the toughness tends to be lowered and should be avoided. Molybdenum is a ferrite-forming element, and copper and manganese are known to be austenite-generating elements. By containing molybdenum, copper, and manganese within the above range, a two-phase structure of austenite and ferrite is obtained. Corrosion resistance is improved.

  As the connecting member, stainless steel, Ti or Ti alloy, aluminum or aluminum alloy, magnesium or magnesium alloy, Ni-Ti alloy, Cu alloy, or Ni alloy are all adhesive to the brazing material. Therefore, it can be preferably used as a material constituting the connecting member. The shape of the connecting member is, for example, a pipe, a pipe having a large number of holes, a mesh-like pipe (a wire knitted into a pipe), a coiled wire (a wire wound in a coil) Etc. can be used.

  As a brazing material that joins the tip side member and the base end side member, it is easy to get wet with the material to be joined, has a melting temperature range suitable for joining work, penetrates into the gap at the joining interface by capillary force, and is a machine necessary as a joint It preferably has electrical, electrical and chemical properties. Although not limited, examples of hard brazing materials include aluminum alloy brazing, phosphor copper brazing, silver brazing, and gold brazing, and soft brazing materials include single metals such as zinc and lead, Sn-Pb alloys. , Cd—Zn alloys, Pb—Ag alloys, Sn—Ag alloys, and the like. Among these, silver solder excellent in compatibility with stainless steel and Ni is preferable. Since silver brazing has high fluidity, it can be preferably used as the brazing material of the present invention in that it can instantaneously flow into a small gap by capillary action. Furthermore, considering that it is a medical use, those having no cadmium and having a low melting point are preferable. This is because if the melting point is low, the heating time can be shortened, so that the change in the characteristics of the metal wire near the joint due to heating can be further suppressed.

  At the time of brazing, it is preferable to dissolve and remove a substance such as an oxide present at the joining interface so that the material to be joined and the molten solder are easily wetted, and further use a flux to prevent oxidation. Examples of the heat source for brazing include high-frequency induction heating, resistance heating, and ultrasonic waves. However, the brazing material can be melted and filled in the joints by heating for a very short time. High frequency induction heating is preferable in that it can be performed. According to the high-frequency induction heating, the electromagnetic energy can be concentrated at the pinpoint and the local heating can be performed, so that the brazing material can be melted and filled in the gap of the joint in a very short time. As a result, there is an effect that it is possible to suppress a change in the characteristics of the metal wire near the joint due to heating at the time of filling the brazing material.

  The diameter of the tip side member is not limited, but it is about 0.1 to 0.34 mm, and the tip portion has a tapered shape that tapers toward the leading edge, thereby changing the rigidity of the tip portion. Smoothing is preferable for increasing the flexibility of the tip. The diameter of the medical guide wire is set to 0.34 mm according to the standard.

  Although not limited, the guide wire has a total length (the total length of the distal end side member and the proximal end side member) of about 1500 to 1800 mm and the length of the distal end side member of about 500 to 1000 mm. It is preferable for improving the operability of the wire.

  The diameter of the long hole provided in the axial direction of the distal end side member and the proximal end side member is not limited, but is slightly larger than the diameter of the core material to be inserted, specifically 0.08 to 0. The length of the core material to be inserted into the long hole is preferably about 1 to 10 mm, and the length of the long hole is preferably set to be slightly larger than the length of the core material. This is to ensure a clearance for the brazing material to enter.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples, and modifications and changes can be made as appropriate without departing from the technical scope of the present invention.

  FIG. 1 (b) is a side view of the medical guide wire 10 of the present invention having a predetermined length (1600 mm), and FIG. 1 (c) is an enlarged view of the joint of FIG. 1 (b). As described above, the length of the guide wire 10 is selected in the range of 1500 to 1800 mm depending on the application.

  In FIG. 1 (c), a guide wire 10 includes a tip-side member 11 having a length of 600 mm formed from a metal wire made of a Ni-Ti alloy (Ni is 51% and the balance is Ti) having a good conformability, and torque. A proximal end side member 12 having a length of 1000 mm formed from a high silicon stainless steel metal wire excellent in transmission, and a proximal end surface 11a of the distal end side member 11 and a distal end side end surface of the proximal end side member 12; 12a is used as a joining end face, and both end faces are arranged to face each other. The diameter of the distal end side member 11 is 0.26 mm, and the diameter of the proximal end side member 12 is also 0.26 mm. The base end side member 12 of high silicon stainless steel was manufactured through a process as described below. That is, by weight%, C = 0.02%, Si = 3.5%, Mn = 2.0%, Ni = 6.0%, Cr = 16.0%, Mo = 1.0%, Cu = A wire rod having a composition of 1.5% and the balance consisting of iron and unavoidable impurities and having a diameter of 6.0 mm is reduced to a diameter of 0.34 mm, and this high silicon stainless steel wire rod having a diameter of 0.34 mm is machined. After performing straight processing, heat treatment was performed for 10 minutes at a temperature of 0 to 600 ° C., and then processing was performed to a diameter of 0.26 mm by centerless grinding.

  In addition, the whole guide wire 10 shown in FIG.1 (b) can be coat | covered with a synthetic resin, and only the front end side member 11 can also be coat | covered with a synthetic resin. As the synthetic resin, polyethylene, polyester, polypropylene, polyurethane, silicon rubber, or the like can be used.

  The proximal end surface 11 a of the distal end member 11 and the distal end end surface 12 a of the proximal end member 12 are inclined surfaces that are inclined with respect to the axial direction of the distal end member 11 and the proximal end member 12. The distal end side member 11 and the proximal end side member 12 are arranged with a first gap 14 into which a brazing material 13 arranged in a ring shape can enter between the inclined end surfaces 11a and 12a. A coiled wire 16, which is a connecting member that covers the outer peripheral surface of the joint portion 15 between the member 11 and the base end side member 12 and covers a part of the outer periphery of the distal end side member 11 following the joint portion 15, A second gap 17 into which the brazing material 13 can enter is provided between the outer peripheral surface of the joint 15 and the first gap 14 and the second gap 17 are filled with the brazing material 13 so that the distal end side member 11 is filled. The base end side end face 11a and the base end side end face 12a of the base end side member 12 are joined. A gray colored portion in FIG. 1C indicates a brazing portion where the brazing material 13 is filled. In order to improve the bonding adhesion strength by the brazing material 13, the outer peripheral surfaces of the joining end surfaces 11 a and 12 a and the joining portion 15 are preliminarily plated with Ni before the brazing material 13 is filled. The coiled wire 16 is a flat spring having a rectangular cross section (see FIG. 1 (d)) having a thickness t of 0.04 mm and a width w of 0.2 mm made of SUS304. The total length L is 15 mm. The length d of the coiled wire 16 covering the outer periphery of the portion 15 is 3 mm, and the outer diameter D of the coiled wire 16 is 0.34 mm.

  The length L of the coiled wire 16 is preferably 5 to 50 mm. If the length of the coiled wire 16 is shorter than 5 mm, the rigidity change from the proximal end member to the distal end member is not smooth, so it is somewhat difficult to accurately transmit the hand operation at the proximal end portion to the distal end portion. When the length is longer than 50 mm, the length of the distal end side member with small rigidity is insufficient, and it is somewhat difficult to perform a delicate operation at the distal end portion.

  The length d of the coiled wire 16 covering the outer periphery of the joint 15 is preferably 2 to 5 mm. If the length is shorter than 2 mm, the bonding strength is insufficient. If the length is longer than 5 mm, the bonding area of the brazing material becomes excessive, and the heating time of the bonding portion increases, and the characteristics of the metal wire near the bonding portion may change. is there.

  It is preferable that the coil wire 16 has a rectangular cross section with a thickness t of 0.01 to 0.05 mm and a width w of 0.07 to 0.30 mm. This is because by having an appropriate rigidity, both flexibility and operability can be achieved.

  The dimensions of the first gap 14 and the second gap 17 are preferably 3 to 10 μm. This is because if the thickness is 3 to 10 μm, the brazing material 13 is likely to enter the gap due to capillary action. If the dimensions of the first gap 14 and the second gap 17 are smaller than 3 μm, there is an inconvenience that the brazing material 13 is difficult to enter. If the dimensions of the first gap 14 and the second gap 17 are larger than 10 μm, there is an inconvenience that the distal end side member 11 and the proximal end side member 12 are easily detached from the coiled wire 16. The first gap 14 and the second gap 17 in the first embodiment are 5 μm and 10 μm, respectively.

  The inclination angles α and β of the joining end surfaces 11 a and 12 a of the distal end side member 11 and the proximal end side member 12 are joined to the inclination angle α with respect to the axis of the joining end surface 11 a of the distal end side member 11. It is preferable that the inclination angle β with respect to the axis of the end face 12a is slightly increased so that the first gap 14 is slightly wedge-shaped. By doing so, the brazing material can easily enter the gap. In this embodiment, the inclination angles α and β are 22 ° and 25 °, respectively.

  The guide wire 10 of Example 1 was manufactured as described below. First, the distal end side member 11 and the proximal end side member 12 are each formed with a predetermined material and with a predetermined dimension, and as shown in FIG. 1A, the proximal end side end surface 11a of the distal end side member 11 is on the lower side. It arrange | positioned on the both sides of the coil-shaped wire 16 so that the front end side end surface 12a of the member 12 may become upper.

  And as shown in FIG.1 (b), the front end side member 11 and the base end side member 12 are pushed in in the coil-shaped wire 16, and the junction part outer peripheral surface of the front end side member 11 and the base end side member 12 and coil shape are carried out. The dimension of the gap between the inner peripheral surface of the wire 16 (second gap 17; see FIG. 1C) is uniform over the entire length and the entire circumference of the coiled wire 16, and the distal end side member 11 and the proximal end side member 12 Is held at a position where the dimension of the gap between the joining end faces 11a and 12a (see the first gap 14 and FIG. 1C) becomes a predetermined size, and brazing material (silver The coiled wire 16 was heated by a high-frequency induction heating device (not shown) with the wax 13 placed in a ring shape. Reference numeral 18 denotes a coil of the high-frequency induction heating device.

  By this heating, as shown in FIG. 1C, the brazing material 13 placed at the end of the coiled wire 16 is melted and first flows into the second gap 17, and then the first gap. 14, the first gap 14 and the second gap 17 were filled with the brazing material 13, and the distal end side member 11 and the proximal end side member 12 were joined. Since the length of the coiled wire 16 covering the outer periphery of the joint 15 is short and is heated by a high-frequency induction heating device, the brazing material 13 instantaneously passes through the second gap 17 at the instant when it melts, and then the first gap 14. Thus, the first gap 14 and the second gap 17 were filled with the brazing material 13 instantaneously.

  The heating temperature can be set according to the melting temperature of the brazing material 13, and is generally 550 to 900 ° C., but the melting point of the silver brazing constituting the brazing material 13, the coiled wire 16 and the coil shape In consideration of changes in metal properties due to heat received by the distal end side member 11 and the proximal end side member 12 on both sides of the wire 16, 650 to 700 ° C. is preferable. The heating temperature is set in this way, the joint is locally heated by the high-frequency induction heating device, the heat source is concentrated, and the joint is heated pinpointly, so that the distal end side members 11 on both sides of the coiled wire 16 are used. And the thermal influence on the base end side member 12 can be suppressed to the minimum.

  In the first embodiment, the proximal end surface 11 a of the distal end member 11 and the distal end surface 12 a of the proximal end member 12 are inclined with respect to the axial direction of the distal end member 11 and the proximal end member 12. 2 (a) and 2 (b), the joining end face is formed into an uneven structure, and the distal end side member 19 and the proximal end side member 20 or the distal end side member 21 and the proximal end side member 22 are connected to each other. It can also be joined.

  Furthermore, in order to make the diameter difference at the joint portion as small as possible so that it can be smoothly inserted into the treatment-needed tube, the distal end side member 23 and the proximal end side member 24 are joined as shown in FIG. Members 26 such as resin can be built up at both ends of the joining member 25.

  Fig.4 (a) is sectional drawing of Example 2 of the medical guidewire of this invention. In FIG. 4A, a guide wire 27 is excellent in torque transferability with a distal end side member 28 formed of a metal wire made of a Ni—Ti alloy (Ni is 51% and the balance is Ti) having good form adaptability. And a base end member 29 formed of a metal wire made of high silicon stainless steel. The distal end side member 28 and the proximal end side member 29 are respectively provided with long holes 30 and 31 in the axial direction of the distal end side member 28 and the proximal end side member 29 that are slightly larger than the diameter of the core material described later. Yes. In order to improve the bonding strength of the brazing material, the inner surfaces of the long holes 30 and 31 are plated with Ni.

  As shown in FIG. 4B, the core member 32 is inserted into the long holes 30 and 31, and the distal end side member 28 and the proximal end side member 29 are arranged with a gap through which the brazing material can enter. In order to improve the bonding adhesion strength by the brazing material, Ni plating is applied to the bonding end faces 28a and 29a.

  Then, with the brazing material 33 placed on the joint, the joint is heated by a high frequency induction heating device (not shown). Reference numeral 34 denotes a high frequency induction heating coil. By this heating, the brazing material 33 placed at the joint is melted, the brazing material 33 is filled into the gap between the long holes through the joining end faces 28a and 29a, and the distal end side member 28 and the proximal end side member 29 are joined. Is done. Since it is heating by high-frequency induction heating, the brazing material 33 is instantaneously filled into the elongated hole through the joining end face at the moment of melting, so that the leading end side member 28 and the base end side member 29 on both sides of the joining portion are filled. Thermal effects can be minimized.

Next, in order to compare the bonding strength, torque transmission and bendability with a conventional guide wire, first, a medical guide wire similar to the structure shown in FIG. 8 was manufactured as a comparative example. That is, the first wire 2 (corresponding to the distal end side member 11 of Example 1) is made of the same material (Ni—Ti alloy) as in Example 1 and has a diameter of 0.26 mm and a length of 600 mm, and the second wire 3 (Example). 1 (corresponding to the base end side member 12) of the same material (high silicon stainless steel) as in Example 1 with a diameter of 0.26 mm and a length of 1000 mm, and a tubular connecting member 8 (corresponding to the coiled wire 16 of Example 1) Is the same material (SUS304) as in Example 1, the outer diameter is 0.34 mm, the thickness is 0.04 mm, the length is 15 mm, and the gap for filling the brazing material 9 is the same dimension (10 μm) as the second gap 17. A brazing material (silver brazing) was heated to fill the gaps.
(1) Bonding strength With respect to the medical guidewire 10 of the present invention having the shape shown in FIG. 1B and the medical guidewire of the comparative example, a tensile test is performed by a tensile tester to measure the breaking load of each specimen. Thus, the bonding strength was compared. The results are shown in Table 1 below.

As is apparent from Table 1, the bonding strength of the medical guide wire of the present invention is extremely higher than that of the comparative example, and it can be seen that the medical guide wire of the present invention is strongly bonded.
(2) Torque transmission property FIG. 5 is a schematic perspective view of a test apparatus for evaluating the torque transmission property of a guide wire. Using the apparatus shown in FIG. 5, an arm 36 is attached to the base end 35 of the medical guide wire of the present invention and the medical guide wire of the comparative example having the shape shown in FIG. The torque generated at the distal end portion 37 was measured by an electronic balance 39 through an arm 38 attached to the distal end portion 37. Table 2 below shows the torque measured by the above method as a torque transmission index with the guide wire of the comparative example as 100.

As apparent from Table 2, the medical guidewire of the present invention has a higher torque transmission index than that of the comparative example, and the medical guidewire of the present invention has excellent torque transmission. I understand.
(3) Bendability In order to know the operability as an actual guide wire, the bendability was investigated by the method described below. That is, as shown in FIG. 6 (a), when the medical guide wire of the present invention shown in FIG. 1 (b) is bent, the change in rigidity from the proximal side member 40 to the distal side member 41 is smooth. The bent portion 42 can be bent into a shape close to a perfect circle with the joint 42 as the center of symmetry.

  However, since the rigidity of the proximal end side member and the distal end side member of the medical guide wire of the comparative example is greatly different, as shown in FIG. 6B, when the medical guide wire of the comparative example is bent, the joint portion 43 As a boundary, the curvature radius of the first wire 2 corresponding to the distal end member having a small rigidity is small, and the curvature radius of the second wire 3 corresponding to the proximal end member having a large rigidity is large. .

  As described above, the medical guide wire according to the present invention has a smooth change in rigidity from the proximal end member to the distal end member, and can transmit the operation on the proximal end member to the distal end member almost accurately. It is. As a result, the distal end portion can be optionally inserted into the treatment tube.

FIG. 1A is a view for explaining a manufacturing method of an embodiment of the medical guide wire of the present invention, and FIG. 1B is a side view of the embodiment of the medical guide wire of the present invention. FIG. 1C is an enlarged view of the joint of FIG. 1B, and FIG. 1D is a cross-sectional view of the coiled wire. FIGS. 2A and 2B are side views showing another embodiment of the medical guide wire joining method of the present invention. It is a side view which shows another Example of the medical guide wire joining method of this invention. 4 (a) and 4 (b) are diagrams for explaining a manufacturing method of still another embodiment of the medical guide wire of the present invention. It is a schematic perspective view of the test apparatus for evaluating the torque transmission property of a guide wire. FIGS. 6A and 6B are diagrams for comparing the bendability of the guide wires. It is sectional drawing of the conventional medical guidewire. It is sectional drawing of the junction part of another conventional medical guide wire.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Guide wire 11 Front end side member 11a Base end side end surface 12 Base end side member 12 Base end side member 12a Front end side end surface 13 Brazing material 14 1st clearance 15 Joint part 16 Coiled wire 17 17 2nd clearance 18 High frequency induction heating Coil of apparatus 19 Front end side member 20 Base end side member 21 Front end side member 22 Base end side member 23 Front end side member 24 Base end side member 25 Joint member 26 Overlay member 27 Guide wire 28 Front end side member 28a Joint end face 29 Base end Side member 29a Joint end face 30 Long hole 31 Long hole 32 Core material 33 Brazing material 34 Coil of high frequency induction heating device 35 Base end portion 36 Arm 37 Front end portion 38 Arm 39 Electronic balance 40 Base end side member 41 Front end side member 42 Joint portion 43 joints

Claims (5)

  It has a distal end side member formed from a metal wire with good conformability and a proximal end member formed from a metal wire excellent in torque transmission, and the proximal end surface and the proximal end side of the distal end member In a medical guide wire formed by joining both members with the distal end surface of the member as a joining end surface, a gap into which a brazing material can enter is provided between the joining end surfaces of the distal end member and the proximal end member. A gap into which the brazing material can enter is provided between the connecting member that covers the outer peripheral surface of the joint portion of the side member and the base end side member, and the outer peripheral surface of the joint portion. And a proximal end member, and the connecting member covers the outer periphery of the joint portion and the outer periphery of a part of the distal end side member following the joint portion.   The medical guide wire according to claim 1, wherein the joining end surface is an inclined surface inclined with respect to the axes of the distal end side member and the proximal end side member.   3. The medical guide wire according to claim 1, wherein the joint end face and the joint outer peripheral surface are preliminarily plated with Ni before filling with the brazing material.   It has a distal end side member formed from a metal wire with good conformability and a proximal end member formed from a metal wire excellent in torque transmission, and the proximal end surface and the proximal end side of the distal end member In a medical guide wire formed by joining both members with the distal end side end surface of the member as a joining end surface, a long hole into which a core material can be inserted is formed on the joining end surface of the distal end side member and the proximal end side member. Provided in the axial direction of the end side member, a gap into which the brazing material can enter is provided between the joining end surfaces of the distal end side member and the proximal end side member, a core material is inserted into the elongated hole, and the brazing material is brazed to the joining end surface. A medical guide wire, wherein a distal end side member and a proximal end side member are joined by being filled with a material.   5. The medical guide wire according to claim 4, wherein the joint end face and the long hole inner face are preliminarily plated with Ni before filling with the brazing material.

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