JP2012055731A5 - - Google Patents

Description

Medical guidewire

The present invention relates to a medical guide wire suitable for the medical field 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 part.

In general, medical guidewires are required to have flexibility on the distal end side and ease of hand operation to be transmitted to the distal end side.
Therefore, in order to satisfy the above requirements, 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, and the distal end portion 103 of the core shaft 101 is thinly processed to improve flexibility. There is something (see FIG. 8).

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.

Further, in the technique of positively bending the guide wire 100 into the U-shape and introducing it into the blood vessel, only the very distal end portion of the guide wire 100 is moved in accordance with the blood vessel diameter or blood vessel shape into which the guide wire 100 is inserted. There is a case where it is sufficient to bend the character, or there is a case where the entire distal end portion of the guide wire 100 needs to be bent into a U shape.

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.

Some guidewires 100 have a twisted wire structure at the tip 103 of the core shaft 101 (see Patent Document 1). However, such a guidewire 100 has a certain degree of resilience from a bent state. When bent into a U-shape with a large curvature, even if the U-shape was released, it was not restored, and the problem of the residual angle was not solved.

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 tip end portion 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 its purpose is to improve the recovery from the U-shaped bending of the guide wire tip, and to develop the U-shaped bending of the guide wire when using the guide wire. There is in prevention of.

[Means of Claim 1]
The medical guide wire according to claim 1 (hereinafter referred to as a guide wire) includes a core shaft having a thin tip, an outer flexible tube surrounding an outer periphery of the core shaft, and the outer flexible tube. Especially for the one provided with an inner flexible tube surrounding the tip of the core shaft inside the body, and a tip joint that joins the tip of the core shaft and the tip of the outer flexible tube. The tip of the inner flexible tube and the core are not joined to the outer flexible tube so that the tip of the inner flexible tube is positioned away from the tip of the core shaft toward the rear end. It has the 1st junction part which joined the shaft, It is characterized by the above-mentioned.

According to this, the 1st junction part which joined the front-end | tip of an inner side flexible tube and a core shaft is provided so that the front-end | tip of an inner side flexible tube may be spaced apart and located in the back end side from the front-end | tip of a core shaft. Therefore, even when the medical guide wire is used, even if it bends in a U shape in the lumen of a blood vessel or the like, the bending is caused by the presence of the first joint portion having a high rigidity. It becomes difficult to develop. That is, when the medical guide wire is bent unintentionally in the blood vessel, even if the user pushes the medical guide wire at hand, the presence of the first joint portion having high rigidity causes the first joint portion to be bent. Bending stops in front and U-shaped bending does not develop. As a result, the development of the U-shaped bend can be limited to the distal end portion of the medical guide wire excellent in flexibility. That is, since the U-shaped bend is performed at a portion where high recoverability is ensured, the medical guidewire is not plastically deformed while being bent, and the recoverability of the medical guidewire is improved.

[Means of claim 2]
The guide wire according to claim 2 is the medical guide wire according to claim 1, wherein the inner flexible tube has a tapered shape in which the outer diameter gradually decreases toward the tip. Features.
According to this, since the rigidity of the inner flexible tube gradually decreases toward the tip, it is possible to provide a gradually changing stiffness structure in which the guide wire is directed toward the tip and the rigidity is decreased. For this reason, generation | occurrence | production of the stress concentration by the sudden change of rigidity can be reduced. In addition, by reducing the diameter of the distal end side of the inner flexible tube, the flexibility of the guide wire is improved, and the insertion property into the peripheral portion of the lumen is improved.

[Means of claim 3]
The guide wire according to claim 3 is the medical guide wire according to claim 1, wherein the inner flexible tube has an outer diameter that gradually decreases toward the tip. .
According to this, the guide wire can have a rigid gradual change structure as in the second aspect, and the insertion property into the lumen peripheral portion can be improved. Moreover, the desired position of an inner side flexible tubular body can be set to desired rigidity by making it thin in steps.

[Means of claim 4]
A guide wire according to claim 4 is the medical guide wire according to claim 2 or 3, wherein the inner flexible tube has a constant inner diameter from the front end to the rear end.
According to this, it becomes easy to insert the core shaft and the stranded wire into the inner flexible tubular body, and it is possible to facilitate the assembly of a suitable guide wire.

[Means of claim 5]
The guide wire according to claim 5 is the medical guide wire according to any one of claims 1 to 4, wherein the inner flexible tube is a multiple hollow formed by twisting a plurality of metal strands. It is a stranded wire coil.
According to this, torque transmission nature improves compared with a single wire coil by making an inner side flexible tube into a multi-row hollow twisted wire coil. For this reason, since a guide wire can be operated according to a user's aim, treatment time can be shortened.

[Means of claim 6]
The guide wire according to claim 6 is the medical guide wire according to any one of claims 1 to 5, wherein the outer flexible tube is a single coil, and is predetermined from a tip of the outer flexible tube. In the distance range, it is provided with a pitch expansion portion in which the pitch of the single coil is wider than the rear end portion of the outer flexible tubular body, and the first joint portion is disposed within the range of the pitch expansion portion. Features.
According to this, the flexibility of the tip of the guide wire can be ensured and a smoother gradual change structure can be formed.

(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. (A), (b) is a figure which shows the U-shaped bending development in the blood vessel of the guide wire front-end | tip part (Example 1). (Example 1) which is a figure which shows the U-shaped bending development in the blood vessel of the front-end | tip part of a guide wire. It is side part sectional drawing of the guide wire front-end | tip part (Example 2). 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 (modified example). 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, and an inner side surrounding the core shaft tip inside the outer flexible tube. A flexible tube.
The tip of the core shaft is joined to the tip of the outer flexible tube, and the inner flexible tube is arranged so that the tip is positioned away from the tip of the core shaft to the rear end side. A first joint where the distal end of the flexible tube and the core shaft are joined, and at least one second joint obtained by joining the outer flexible tube and the inner flexible tube on the rear end side of the first joint. Are provided.

The core shaft has a small-diameter portion formed in a small diameter through a step portion at the tip, and the second joint portion is provided at a position in the vicinity of the step portion in the axial direction.
The inner flexible tubular body is a multi-row hollow stranded coil formed by twisting a plurality of metal strands, and has a tapered shape in which the outer diameter gradually decreases toward the tip. Further, the inner flexible tube 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.

The outer flexible tubular body is a single coil, and includes 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 rear end of the pitch enlarged portion is disposed on the rear end side with respect to the first joint portion.

The guide wire of the best mode 2 includes a stranded wire disposed in parallel with the tip portion of the core shaft inside the inner flexible tube.

[Configuration of Example 1]
The structure of the guide wire 1 of Example 1 is demonstrated using FIGS. 1 and 2, the right side in the figure is the front end side, and the left side is the rear end side.
The guide wire 1 includes a core shaft 2, an outer flexible tube 4 through which the core shaft 2 is inserted, and an inner flexible tube 5 provided inside the outer flexible tube 4. Are inserted into the inner flexible tube 5 and 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 thinned 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 outer flexible tube 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 wire coil of 0.355 mm. .
Moreover, the outer side flexible tube 4 has the pitch expansion part 43 by which the coil pitch was expanded only at the front end side in order to give a softness | flexibility by the front end side. This pitch expansion is performed in the axial direction from the front end 51 of the inner flexible tube 5 described later to the rear end side.
In addition, the outer side flexible tube body 4 should just have flexibility, and may be not only a single coil but a hollow stranded wire coil, a resin tube, etc.

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 inner flexible tubular body 5 is a hollow stranded coil formed of a plurality of stainless steel wires. The hollow stranded coil has a hollow form in which a plurality of strands are twisted into a rope shape using a rope twisting machine and the center material is removed, or a form in which a plurality of strands are twisted into a hollow shape. preferable.
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 inner side flexible tubular body 5 is processed into the taper shape by which an outer diameter becomes small toward a front-end | tip by electropolishing. The inner flexible tube 5 has a constant inner diameter from the rear end to the front end.

The inner flexible tube 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 distal end 51 of the inner flexible tube 5 is positioned on the rear end side of the distal end of the outer flexible tube body 4, and the rear end 53 of the inner flexible tube body 5 is positioned on the distal end side of the rear end 42 of the outer flexible tube body 4.

Further, in relation to the core shaft 2, the front end 51 of the inner flexible tube 5 is located on the rear end side with respect to the front end of the core shaft 2 and on the front end side with respect to the rear end of the small diameter portion 25. The rear end 53 of the flexible tube 5 is located on the rear end side from the step portion 23.
In other words, the inner flexible tube 5 is arranged so that the front end 51 is spaced from the front end of the core shaft 2 toward the rear end side in the axial direction.

The guide wire 1 is provided with a first joint 6 where the tip 51 of the inner flexible tube 5 and the core shaft 2 are joined. Specifically, the inner flexible tube body 5 and the core shaft 2 are fixed by soldering at the tip position of the inner flexible tube body 5 to form the first joint portion 6. Further, the rear end of the pitch expanding portion 43 is located on the rear end side with respect to the first joint portion 6.
The rear end 53 of the inner flexible tube 5 is fixed to the outer peripheral surface of the core shaft 2.

The guide wire 1 is provided with two second joint portions 7a and 7b in which the outer flexible tube body 4 and the inner flexible tube body 5 are joined on the rear end side of the first joint portion 6. Yes.
The second joint portion 7a is configured such that the outer flexible tubular body 4 and the inner flexible tubular body 5 are fixed by soldering at the position of the step portion 23 in the axial direction.
The second joint portion 7b is located at the rear end side of the second joint portion 7a and the front end side of the rear end 53 of the inner flexible tube body 5 in the axial direction, and the outer flexible tube body 4 and the inner flexible tube body 5. Are fixed by soldering.

[Effects of Example 1]

In the guide wire 1 of the present embodiment, the distal end portion 22 of the core shaft 2 is gradually reduced toward the distal end, and the inner flexible member that surrounds the distal end portion 22 of the core shaft 2 inside the outer flexible tubular body 4. A tube 5 is provided. According to this, since the inner side flexible tube 5 surrounds the outer periphery of the core shaft 2 that has been reduced in diameter to ensure flexibility, the restoring property of the guide wire 1 is improved.

Further, the inner flexible tube 5 is arranged so that the tip 51 thereof is located away from the tip of the core shaft 2 toward the rear end, and the tip 51 of the inner flexible tube 5 and the core shaft 2 are arranged. The 1st junction part 6 to join is provided.

According to this, there is a difference in rigidity between the front end side and the rear end side of the first joint portion 6, and the first joint portion 6 has high rigidity. That is, the front end side of the first joint portion 6 is “outer flexible tube body 4 + core shaft 2”, and the rear end side of the first joint portion 6 is “outer flexible tube body 4 + inner flexible tube body 5 + core shaft”. 2 ”, a difference in rigidity occurs at the boundary of the first joint 6, and the rigidity of the first joint 6 is high because the tip 51 of the inner flexible tube 5 and the core shaft 2 are fixed by soldering. Become.

For this reason, when the guide wire 1 is used, even if it bends in a U shape in the lumen of a blood vessel or the like, the bending is caused by the existence of the first joint portion 6 having high rigidity, and the rear end of the first joint portion 6 It becomes difficult to develop on the side.
That is, when the guide wire 1 is unintentionally bent in the blood vessel (see FIG. 3A), even if the user pushes the guide wire 1 at hand, the first joint with high rigidity is used. Due to the presence of the portion 6, the bending stops before the first joint portion 6 (see FIG. 3B), and the U-shaped bending does not develop.

As a result, the development of the U-shaped bend can be limited to the distal end portion of the guide wire 1 having excellent flexibility. That is, since the U-shape is bent at a portion where high recoverability is ensured, the guidewire 1 is not plastically deformed while being bent, and the recoverability of the guidewire 1 is improved.

Further, the guide wire 1 is provided with at least one second joint portion 7a, 7b obtained by joining the outer flexible tube body 4 and the inner flexible tube body 5 on the rear end side of the first joint portion 6. Yes.
Thereby, even if the U-shaped bend development cannot be stopped at the first joint portion 6 and the rear end side of the first joint portion 6 is bent, the second joint portion 7a having high rigidity on the rear end side of the first joint portion 6 is obtained. , 7b, the U-shaped bending hardly develops on the rear end side from the second joint portions 7a, 7b (see FIG. 4). That is, it is possible to prevent the U-bending of the guide wire 1 from developing step by step between the first joint 6 and the second joints 7a and 7b.
Since the U-shaped bending stops at the second joints 7a and 7b, the U-shaped bending is performed only at a portion where the inner flexible tubular body 5 having an excellent restoring property is present. Good resiliency.

Further, in the technique of positively bending the guide wire 1 into the U-shape and introducing it into the blood vessel, only the very distal end portion of the guide wire 1 is moved in accordance with the blood vessel diameter or blood vessel shape into which the guide wire 1 is inserted. There are cases where it is sufficient to bend the character, and there is a case where the entire distal end portion of the guide wire 1 needs to be bent in a U shape.
Therefore, by providing the first joint 6 and the second joints 7a and 7b and providing a U-shaped bending prevention function in stages, the first joint 6 or the second joints 7a and 7b are provided depending on the procedure. However, the U-shaped bend development prevention function can be used properly, and the user can easily operate.

That is, when the guide wire 1 is introduced into a thin blood vessel, the guide wire 1 is bent at the distal end side of the first joint portion 6, so that the first joint portion 6 mainly functions to prevent U-bending development.
In addition, when the guide wire 1 is introduced into a thick blood vessel or the like while being bent in a U shape, the guide wire 1 is inserted into the blood vessel in a state of being bent on the rear end side with respect to the first joint portion 6. The joint portions 7a and 7b serve to prevent U-shaped bending development (see FIG. 4).
In any case, since the U-shaped bend development is stopped at the portion where the recoverability is ensured as described above, the recoverability of the guide wire 1 by releasing the bend is good.

Further, in the present embodiment, since the second joint portion 7a is provided at a position in the vicinity of the step portion 23 in the axial direction, a difference in rigidity between the front and the back is created at the step portion 23 in the core shaft 2, and therefore the second A significant difference in rigidity occurs before and after the joint 7a. For this reason, U-shaped bending development is more effectively suppressed in the second joint portion 7a.

Further, the outer flexible tube 4 is a single coil, and a pitch expansion portion in which the pitch of the single coil is wider than the rear end of the outer flexible tube 4 in a predetermined distance range from the tip of the outer flexible tube 4. 43, and the rear end of the pitch expanding portion 43 is disposed closer to the rear end than the first joint portion 6.
Thereby, the softness | flexibility of the front-end | tip of the guide wire 1 is ensured, and a smoother rigid change structure can be formed.

That is, the guide wire 1 of the present embodiment has a gradually changing rigidity structure in which the bending rigidity increases from the front end side toward the rear end side.
Specifically, from the distal end of the guide wire 1, “the portion with the pitch extension of the outer flexible tube 4 + the core shaft 2”, “the portion with the pitch extension of the outer flexible tube 4 + the inner flexible tube 5 + The bending rigidity gradually increases in the order of the “core shaft 2” portion and the “pitch unextended portion of the outer flexible tube 4 + inner flexible tube 5 + core shaft 2” portion. Further, on the rear end side, the bending rigidity gradually increases due to the change in the diameter of the core shaft 2.
For this reason, generation | occurrence | production of the stress concentration by the sudden change of rigidity can be reduced more, and torque transmission nature improves.

Further, since the inner flexible tubular body 5 is a multi-strand hollow stranded wire coil, torque transmission is improved as compared with a single wire coil. For this reason, since the guide wire 1 can be operated as intended by the user, the treatment time can be shortened.
Moreover, since the front-end | tip part 52 of the inner side flexible tubular body 5 is formed in the taper shape which becomes thin gradually toward a front-end | tip, the rigid gradual change structure of the guide wire 1 mentioned above can be set more finely and smoothly. Moreover, by making the diameter of the distal end side of the inner flexible tube 5 thinner, the flexibility of the guide wire 1 is improved and the insertion property into the distal portion of the lumen is improved.

In addition, since the inner diameter of the inner flexible tube body 5 is constant from the front end to the rear end, the core shaft 2 can be easily inserted into the inner flexible tube body 5 and the assembly of the preferred guide wire 1 is facilitated. Can do.

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

[Configuration of Example 2]
The configuration of the guide wire 11 according to the second embodiment will be described with reference to FIG. 5 with a focus on differences from the first embodiment. In FIG. 5, the right side in the figure is the front end side, and the left side is the rear end side.
The guide wire 11 according to the present embodiment includes a stranded wire 8 disposed in parallel with the distal end portion 22 of the core shaft 2 inside the inner flexible tubular body 5. The guide wire 11 is formed by inserting the stranded wire 8 together with the core shaft 2 into the inner flexible tube 5 and further inserting these into the outer flexible tube 4.

The stranded wire 8 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 8 is arranged in parallel with the distal end portion 22 of the core shaft 2, and the distal end of the stranded wire 8 is soldered to the distal end brazing portion 41 at the distal end of the outer flexible tubular body 4 together with the distal end of the core shaft 2. The rear end of the stranded wire 8 is located on the rear end side of the rear end of the small diameter portion 25 of the core shaft 2, and is soldered to the inner flexible tube 5 together with the core shaft 2.

[Effects of Example 2]
Since the stranded wire 8 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 the twisted wire 8 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 restoring property from the U-shaped bending of the guide wire 11 is improved.

[Modification]
In the first and second embodiments, the distal end portion 22 of the core shaft 2 is tapered stepwise toward the distal end, but may be tapered toward the distal end.

In Example 1 and Example 2, the core shaft 2 was formed of a stainless alloy, but the tip portion (at least the small diameter portion 25) of the core shaft 2 was excellent in resilience (for example, Ni- Ti alloy) and the rear end side may be formed of a stainless alloy. According to this, while restoring property of the front-end | tip part of the guide wires 1 and 11 can be improved, torque transmission property and operativity can be improved.

Further, as shown in FIG. 6, 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 made of a stainless alloy on both the front end side and the rear end side of the portion made of the pseudoelastic alloy, the torque on the rear end side can be reliably transmitted to the front end side. Transmission and operability can be further improved.

Moreover, in Example 1 and Example 2, although the front-end | tip part 52 of the inner side flexible tubular body 5 was taper-shaped toward the front-end | tip, you may make it thin in steps.

Moreover, in Example 1 and Example 2, although the inner side flexible tube 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 inner side flexible tubular body 5 can be further enhanced.
Further, the inner flexible tube 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 inner inner flexible tube 5 can be increased with the stainless alloy, and the restoring property of the inner inner flexible tube 5 can be increased with the pseudoelastic alloy. For this reason, the torque transmission property, operability, and restoration property of the guide wires 1 and 11 can be improved.

The guide wires 1 and 11 of the first and second embodiments have a structure in which the outer flexible tubular body 4 surrounds only the distal end side of the core shaft 2, but the outer flexible tubular body 4 covers the entire core shaft 2. A structure to be packaged may be used.

The guide wires 1 and 11 of the first and second embodiments are configured by joining only the outer flexible tubular body 4 and the inner flexible tubular body 5 at the second joint portions 7a and 7b. Solder may be poured into the flexible tube 5 and fixed. That is, for example, in the guide wire 11 of the second embodiment, the joining portion 7a is configured by fixing the outer flexible tube body 4, the inner flexible tube body 5, the stranded wire 8, and the core shaft 2 by soldering. It is also possible (see FIG. 7).

DESCRIPTION OF SYMBOLS 1 Guide wire 11 Guide wire 2 Core shaft 22 Core shaft front-end | tip part 23 Step part 25 Small diameter part 26 1st front-end | tip part 27 2nd front-end | tip part 4 Outer flexible tubular body 43 Pitch expansion part 5 Inner flexible tubular body 51 Inside Tip 6 of flexible tube 1st joining part 7a 2nd joining part 7b 2nd joining part 8 Stranded wire

Claims (6)

A core shaft having a narrow tip, and
An outer flexible tube surrounding the outer periphery of the core shaft;
An inner flexible tube surrounding the tip of the core shaft inside the outer flexible tube;
In a medical guide wire provided with a tip joint portion joining the tip of the core shaft and the tip of the outer flexible tube,
The tip of the inner flexible tube and the core shaft are not joined to the outer flexible tube so that the tip of the inner flexible tube is positioned away from the tip of the core shaft toward the rear end. A medical guide wire comprising a first joining portion joined together. The medical guidewire according to claim 1,
The medical guide wire according to claim 1, wherein the inner flexible tube has a tapered shape in which an outer diameter gradually decreases toward a tip. The medical guidewire according to claim 1,
The guide wire for medical use, wherein the inner flexible tube has an outer diameter that gradually decreases toward the tip. The medical guidewire according to claim 2 or 3,
The inner flexible tube has a constant inner diameter from the front end to the rear end. The medical guidewire according to any one of claims 1 to 4,
The medical guide wire according to claim 1, wherein the inner flexible tube is a multi-wire hollow stranded coil formed by twisting a plurality of metal strands. The medical guidewire according to any one of claims 1 to 5,
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. Prepared,
The medical guide wire, wherein the first joint portion is disposed within the range of the pitch enlargement portion.