Medical device and method of manufacturing medical device

Abstract

To enhance bonding strength between a coil and a distal end chip in a medical device.SOLUTION: A medical device 100 comprises: a core shaft 10; a distal end chip 30 bonded to the core shaft; a coil 20 which has the core shaft disposed therein and is bonded to the distal end chip. The coil comprises: a first part 21 which is positioned on a proximal end side of a proximal end of the distal end chip and has a coil pitch of a first pitch P1; and a second part 22 which is positioned on a distal end side of the proximal end of the distal end chip and has a coil pitch of a second pitch P2 wider than the first pitch.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] TECHNICAL FIELD The technology disclosed herein relates to medical devices and methods for manufacturing medical devices. [Background technology]

[0002] A guidewire is used as a medical device when treating a stenosis or occlusion in a biological lumen such as a blood vessel. The guidewire has a core shaft, a distal tip joined to the core shaft, and a coil through which the core shaft is inserted and joined to the distal tip.

[0003] In known guidewires, the coil pitch is relatively wide at the distal end, and the coil is joined to the distal tip within a range of less than one pitch (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-143077 Summary of the Invention [Problem to be solved by the invention]

[0005] Known guidewires do not provide sufficient bond strength between the coil and the distal tip.

[0006] This specification discloses a technique that can solve the above-mentioned problems. [Means for solving the problem]

[0007] The technology disclosed in this specification can be realized, for example, in the following forms.

[0008] (1) The medical device disclosed in this specification comprises a core shaft, a distal tip joined to the core shaft, and a coil into which the core shaft is inserted and joined to the distal tip. The coil has a first section located proximally of the distal tip and having a first coil pitch, and a second section located distally of the distal tip and having a second coil pitch wider than the first pitch. According to this medical device, the second section of the coil with a relatively wider coil pitch is located distally of the distal tip. Therefore, the distal tip is firmly joined to the coil at the second section, thereby increasing the joining strength between the coil and the distal tip.

[0009] (2) In the above medical device, the position of the tip of the core shaft in the axial direction of the medical device may be either further distal than the position of the tip of the coil, or the same as the position of the tip of the coil. With this configuration, the length of the portion where the core shaft and the distal tip are in close contact with each other can be increased, thereby increasing the tensile strength of the medical device.

[0010] (3) In the above medical device, the second pitch of the coil may be 1.5 times or more the first pitch. With this configuration, the distal tip is more firmly joined to the coil at the second portion, effectively increasing the joining strength between the coil and the distal tip.

[0011] (4) In the medical device, at least a portion of the coil may be radiopaque. This configuration can improve the visibility of the coil in a radioscopic image while increasing the bonding strength between the coil and the distal tip.

[0012] (5) In the medical device, at least a portion of the surface of the coil may be plated. With this configuration, the wettability of the coil surface can be improved by plating, and the bonding strength between the coil and the distal tip can be increased even if the coil is made of a material that is prone to bonding defects.

[0013] (6) In the above medical device, the position of the proximal end of the second portion may be either further distal than the position of the proximal end of the distal tip in the axial direction of the medical device, or the position may be equal to the position of the proximal end of the distal tip. With this configuration, the proximal end of the distal tip is joined to the second portion of the coil, thereby effectively increasing the joining strength between the coil and the distal tip.

[0014] (7) In the above medical device, the coil may be an outer layer coil. With this configuration, the bonding strength between the outer layer coil and the distal tip can be increased.

[0015] (8) In the above medical device, the coil may be an inner layer coil, and the medical device may include an outer layer coil disposed outside the inner layer coil. With this configuration, the bonding strength between the inner layer coil and the distal tip can be increased.

[0016] (9) A method for manufacturing a medical device disclosed in this specification includes preparing a coil having a first section with a first coil pitch and a second section with a second coil pitch wider than the first pitch, inserting a core shaft into the coil, and forming a joint between the coil and the core shaft in a range including at least one pitch of the second section of the coil. According to this method for manufacturing a medical device, a joint between the coil and the core shaft is formed in a range including at least one pitch of the second section with a relatively wider coil pitch, so that the joint is firmly joined to the coil at the second section, thereby increasing the bonding strength between the coil and the joint (distal tip).

[0017] (10) In the method for manufacturing the medical device, the joining may be performed by soldering. With this configuration, soldering can increase the joining strength between the coil and the joint (distal tip).

[0018] (11) In the method for manufacturing the medical device, a part of the joint may be removed after the joining. With this configuration, the axial length of the joint (distal tip) can be easily controlled.

[0019] (12) In the method for manufacturing the medical device, after the joining, the core shaft may be removed from a distal end side of a first position between the distal end and the proximal end of the joint. This configuration allows the core shaft to extend to the distal end of the joint (distal tip), and the length of the portion where the core shaft and the distal tip are in close contact with each other can be increased, thereby increasing the tensile strength of the medical device.

[0020] (13) In the method for manufacturing the medical device, after the joining, the coil may be removed from a portion of the coil distal to a second position between the distal end and the proximal end of the joint. With this configuration, the distal end of the coil, which is prone to poor joining, is removed, thereby preventing poor joining between the coil and the joint (distal tip).

[0021] (14) In the method for manufacturing the medical device, the distal end of the core shaft may be located distal to the distal end of the bonded portion formed during the bonding. According to this configuration, the core shaft is bonded to the bonded portion proximal to the distal end of the core shaft, thereby preventing poor bonding between the core shaft and the bonded portion (distal tip).

[0022] (15) In the method for manufacturing the medical device, the distal end of the coil may be located distal to the distal end of the joint formed during the joining. With this configuration, the coil is joined to the joint proximal to the distal end of the coil, thereby preventing poor joining between the coil and the joint (distal tip).

[0023] The techniques disclosed in this specification can be realized in various forms, for example, in the form of a medical device, a method for manufacturing a medical device, a treatment method using a medical device, etc. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is an explanatory diagram showing the configuration of a longitudinal section (YZ section) of a guide wire in a first embodiment. [Figure 2] FIG. 1 is an explanatory diagram showing an enlarged longitudinal cross-sectional configuration of a distal end portion of a guide wire according to a first embodiment. [Figure 3] Flowchart showing a method for manufacturing a guidewire according to the first embodiment [Figure 4] FIG. 10 is an explanatory diagram schematically illustrating a method for manufacturing a guidewire according to the first embodiment. [Figure 5] FIG. 10 is an explanatory diagram showing the configuration of a longitudinal section (YZ section) of a guide wire according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0025] (Configuration of guidewire 100) FIG. 1 is an explanatory diagram showing the configuration of a longitudinal cross section (YZ cross section) of a guidewire 100 in the first embodiment. FIG. 2 is an explanatory diagram showing an enlarged longitudinal cross section of the distal end of the guidewire 100 in the first embodiment. In FIG. 1, a portion of the guidewire 100 is not shown. In FIGS. 1 and 2, the guidewire 100 is shown in a linear state parallel to the Z axis. The guidewire 100 is flexible enough to be bent. These points also apply to the subsequent figures.

[0026] In the guidewire 100, the positive Z-axis side is the tip side (distal side) that is inserted into the body, and the negative Z-axis side is the base side (proximal side) that is manipulated by the operator. In this specification, for the guidewire 100 and each of its components, the tip end is referred to as the "tip," the tip and its vicinity are referred to as the "tip portion," the base end is referred to as the "base end," and the base end and its vicinity are referred to as the "base portion." The transverse cross section of the guidewire 100 and each of its components refers to a cross section perpendicular to the longitudinal direction. The longitudinal cross section of the guidewire 100 and each of its components refers to a cross section parallel to the longitudinal central axis. For the guidewire 100 and each of its components, the direction perpendicular to the longitudinal central axis is referred to as the radial direction. The outer diameter of the guidewire 100 and each of its components refers to the width along the radial direction.

[0027] The guidewire 100 is a medical device. The guidewire 100 is long and is inserted into a body lumen such as a blood vessel. The total length of the guidewire 100 is, for example, 1000 mm or more and 3000 mm or less.

[0028] The guidewire 100 includes a core shaft 10 , a coil 20 , a distal tip 30 , and a proximal joint 33 .

[0029] The core shaft 10 is an elongated member. The core shaft 10 includes a thin diameter portion 11, a thick diameter portion 12, and a tapered portion 13. The thin diameter portion 11 is a rod-shaped portion having a substantially constant outer diameter. In this embodiment, the tip of the thin diameter portion 11 coincides with the tip 10d of the core shaft 10 and also coincides with the tip 100d of the guidewire 100. The thick diameter portion 12 is located closer to the proximal end than the thin diameter portion 11 and is a rod-shaped portion having a substantially constant outer diameter smaller than the outer diameter of the thin diameter portion 11. The outer diameter of the thick diameter portion 12 is, for example, 0.2 mm or more and 3.0 mm or less. The tapered portion 13 is located between the thin diameter portion 11 and the thick diameter portion 12 and is a portion whose outer diameter gradually increases from the boundary with the thin diameter portion 11 toward the boundary with the thick diameter portion 12. The cross-sectional shape at each position of the core shaft 10 may be any shape. The shape of the cross section at each position of the core shaft 10 may be, for example, a circle, a partial circle, an ellipse, a rectangle, a parallelogram, a trapezoid, a rhombus, etc. The shape of the cross section may be different for each position along the longitudinal direction of the core shaft 10.

[0030] For example, metal is used as the material for forming the core shaft 10. More specifically, for example, stainless steel (SUS302, SUS304, SUS316, etc.), Ni-Ti alloy, piano wire, etc. may be used. The entire core shaft 10 may be made of the same material, or different portions may be made of different materials.

[0031] The coil 20 is a hollow cylindrical member in which one or more wires are wound in a spiral shape. The core shaft 10 is inserted into the hollow portion of the coil 20. In this embodiment, the coil 20 is arranged to surround a portion of the small diameter portion 11, the tapered portion 13, and a portion of the large diameter portion 12 of the core shaft 10. The tip 20d of the coil 20 is located closer to the base end than the tip 10d of the core shaft 10. The total length of the coil 20 is, for example, 10 mm or more and 500 mm or less. The outer diameter of the coil 20 is, for example, 0.1 mm or more and 2.0 mm or less. In this embodiment, the outer diameter of the coil 20 is constant throughout the entire length of the coil 20. The coil 20 may have a portion whose outer diameter changes along the longitudinal direction. In this embodiment, there are no other coils located outside the coil 20. That is, the coil 20 is an outer layer coil.

[0032] The coil 20 may be formed from, for example, a metal. More specifically, radiotransparent materials such as stainless steel (e.g., SUS302, SUS304, SUS316), Ni-Ti alloys, and piano wire, or radiopaque materials such as platinum, gold, tungsten, and alloys thereof, may be used. The coil 20 may be formed entirely from the same material, or portions may be formed from different materials. If at least a portion of the coil 20 is formed from a radiopaque material, that portion of the coil 20 will have radiopaque properties. For example, to improve wettability, at least a portion of the surface of the coil 20 may be plated. Examples of plating materials include Ni, Au, Sn, Sn-Ni alloys, and SnCu-Ni alloys. For example, the coil 20 may be formed from tungsten, which is a difficult-to-solder material, and the surface of the coil 20 may be plated with a SnCu-Ni alloy, Ni, Au, or the like.

[0033] The distal tip 30 joins the distal end of the core shaft 10 and the distal end of the coil 20. In other words, the distal end of the core shaft 10 and the distal end of the coil 20 are joined to the distal tip 30. The distal end 30d of the distal tip 30 substantially coincides with the distal end 100d of the guidewire 100. The outer peripheral surface on the distal side of the distal tip 30 is a smooth surface (for example, a substantially hemispherical or cylindrical surface). The proximal joint 33 joins the core shaft 10 and the proximal end of the coil 20.

[0034] Materials used to form the distal tip 30 and the base-end joint 33 include, for example, metal solder (Au-Sn alloy, Sn-Ag alloy, Sn-Pb alloy, Pb-Ag alloy, etc.), solder material (aluminum alloy solder, silver solder, gold solder, etc.), adhesive (epoxy adhesive, etc.), etc.

[0035] In this embodiment, the coil 20 has a first region 21 and a second region 22. The first region 21 is a region where the coil pitch is a first pitch P1. The coil pitch is the center-to-center distance between two adjacent wires in the longitudinal direction of the coil 20. The second region 22 is located closer to the tip side than the first region 21 and where the coil pitch is a second pitch P2 that is wider than the first pitch P1. The second pitch P2 is, for example, not less than 1 time and not more than 10 times the first pitch P1. The second pitch P2 is, for example, not less than 1.1 times and not more than 10 times the first pitch P1. The second pitch P2 is, for example, not less than 1.5 times and not more than 10 times the first pitch P1. The second pitch P2 may be not less than 1.7 times and not more than 8 times the first pitch P1, or not less than 2 times and not more than 5 times the first pitch P1. In this embodiment, the position of the boundary between the first region 21 and the second region 22 substantially coincides with the position of the proximal end 30p of the distal tip 30. In other words, the entire first region 21 is located proximally relative to the proximal end 30p of the distal tip 30, and the entire second region 22 is located distally relative to the proximal end 30p of the distal tip 30. In the axial direction of the guidewire 100, the position of the proximal end 22p of the second region 22 is equal to the position of the proximal end 30p of the distal tip 30.

[0036] (Manufacturing Method of Guidewire 100) Fig. 3 is a flowchart showing a method for manufacturing the guidewire 100 according to the first embodiment. Fig. 4 is an explanatory diagram schematically showing a method for manufacturing the guidewire 100 according to the first embodiment.

[0037] First, an operator prepares the coil 20 and the core shaft 10 (S110, the first row from the top in the left column of FIG. 4). The coil pitch of the prepared coil 20 at this time is the first pitch P1 described above over the entire length of the coil 20. The surface of the coil 20 may be plated. Even if the surface of the coil 20 is plated, the tip 20d of the prepared coil 20 is a cut surface, so that no plating is present on this surface and the metal base is exposed.

[0038] Next, the worker adjusts the coil pitch at the tip of coil 20 (S120, second row from the top in the left column of FIG. 4). Specifically, the worker widens the coil pitch at the tip of coil 20 to form second region 22, where the coil pitch is a second pitch P2 that is wider than first pitch P1. The portion of coil 20 where the coil pitch remains at first pitch P1 becomes first region 21.

[0039] Next, the worker inserts the core shaft 10 into the coil 20 (S130, third row from the top in the left column of FIG. 4). At this time, the tip 10d of the core shaft 10 is positioned further forward than the tip 20d of the coil 20.

[0040] Next, the worker joins the coil 20 and the core shaft 10 using solder 110 to form a joint 36 (S140, the fourth row from the top in the left column and the first row from the top in the right column in FIG. 4 ). At this time, the worker supplies the solder 110 from the outer periphery of the second portion 22 of the coil 20. The supplied solder 110 enters the hollow portion of the coil 20 through gaps between the strands of the second portion 22 of the coil 20. As a result, a joint 36 joining the core shaft 10 and the coil 20 is formed over an area including at least one pitch of the second portion of the coil 20. During joining, the tip 10d of the core shaft 10 and the tip 20d of the coil 20 are positioned more distal than the tip 36d of the joint 36 to be formed. Therefore, even if the surface of the coil 20 is plated, the surface of the tip 20d of the coil 20 that is not plated does not come into contact with the solder 110. Therefore, the problem of poor joining due to the absence of plating on the surface of the tip 20d of the coil 20 does not occur. The position of the base end 36 p of the formed joint 36 substantially coincides with the position of the base end 22 p of the second portion 22 of the coil 20 .

[0041] Next, the worker cuts and removes a portion of the tip end of the joint 36, the core shaft 10, and the coil 20 (S150, second row from the top on the right in FIG. 4). The cutting position CP at this time is a position between the tip end 36d and the base end 36p of the joint 36 before cutting. The cutting position CP is an example of the first position and the second position.

[0042] Next, the worker polishes the distal end of the joint 36 (S160, third row from the top in the right column of FIG. 4). This forms the distal tip 30 with a smooth distal end surface. The guidewire 100 of this embodiment is mainly manufactured by the above method.

[0043] (Effects of the first embodiment) As described above, the guidewire 100 of this embodiment includes a core shaft 10, a distal tip 30, and a coil 20. The distal tip 30 is joined to the core shaft 10. The core shaft 10 is inserted into the coil 20. The coil 20 is joined to the distal tip 30. The coil 20 has a first region 21 located proximally of the proximal end 30p of the distal tip 30 and having a coil pitch of a first pitch P1, and a second region 22 located distally of the proximal end 30p of the distal tip 30 and having a coil pitch of a second pitch P2 wider than the first pitch P1. In the guidewire 100 of this embodiment, the second region 22 of the coil 20, which has a relatively wider coil pitch, is located distally of the proximal end 30p of the distal tip 30. Therefore, the distal tip 30 is firmly joined to the coil 20 at the second region 22, thereby increasing the joining strength between the coil 20 and the distal tip 30.

[0044] In the guidewire 100 of this embodiment, the position of the distal end 10d of the core shaft 10 is either closer to the distal end than the position of the distal end 20d of the coil 20, or is equal to the position of the distal end 20d of the coil 20, in the axial direction of the guidewire 100. According to the guidewire 100 of this embodiment, the length of the portion where the core shaft 10 and the distal tip 30 are in close contact with each other can be increased, and the tensile strength of the guidewire 100 can be increased.

[0045] In the guidewire 100 of this embodiment, the second pitch P2 of the coil 20 may be 1.5 times or more the first pitch P1. By adopting such a configuration, the distal tip 30 is more firmly joined to the coil 20 at the second portion 22, and the joining strength between the coil 20 and the distal tip 30 can be effectively increased.

[0046] In the guidewire 100 of this embodiment, at least a portion of the coil 20 may be radiopaque. By adopting such a configuration, it is possible to improve the visibility of the coil 20 in a radioscopic image and also increase the bonding strength between the coil 20 and the distal tip 30.

[0047] In the guidewire 100 of this embodiment, plating may be applied to at least a portion of the surface of the coil 20. By adopting such a configuration, the wettability of the surface of the coil 20 can be improved by plating, and the bonding strength between the coil 20 and the distal tip 30 can be increased even if the material forming the coil 20 is prone to bonding defects.

[0048] In the guidewire 100 of this embodiment, the position of the proximal end 22p of the second portion 22 of the coil 20 is either closer to the distal side than the position of the proximal end 30p of the distal tip 30, or is equal to the position of the proximal end 30p of the distal tip 30. According to the guidewire 100 of this embodiment, the proximal end of the distal tip 30 is joined to the second portion 22 of the coil 20, so that the joining strength between the coil 20 and the distal tip 30 can be effectively increased.

[0049] In the guidewire 100 of this embodiment, the coil 20 is an outer layer coil. According to the guidewire 100 of this embodiment, the bonding strength between the outer layer coil and the distal tip 30 can be increased.

[0050] The method for manufacturing the guidewire 100 of this embodiment includes preparing a coil 20 having a first region 21 with a coil pitch of a first pitch P1 and a second region 22 with a coil pitch of a second pitch P2 that is wider than the first pitch P1, inserting the core shaft 10 into the coil 20, and forming a joint 36 that joins the coil 20 to the core shaft 10 in a range that includes at least one pitch of the second region 22 of the coil 20. In the method for manufacturing the guidewire 100 of this embodiment, the joint 36 that joins the coil 20 to the core shaft 10 is formed in a range that includes at least one pitch of the second region 22 of the coil 20, where the coil pitch is relatively wider. Therefore, the joint 36 is firmly joined to the coil 20 at the second region 22, and the joining strength between the coil 20 and the joint 36 (distal tip 30) can be increased.

[0051] In the method for manufacturing the guidewire 100 of this embodiment, the above-mentioned joining is performed by soldering. In the method for manufacturing the guidewire 100 of this embodiment, soldering is performed in a range that includes at least one pitch of the second portion 22, which has a relatively wide coil pitch in the coil 20, thereby making it possible to increase the joining strength between the coil 20 and the joint portion 36 (distal tip 30).

[0052] In the method for manufacturing the guidewire 100 of this embodiment, after the above-mentioned joining, a part of the joint 36 is removed. In the method for manufacturing the guidewire 100 of this embodiment, the axial length of the joint 36 (distal tip 30) can be easily controlled.

[0053] In the method for manufacturing the guidewire 100 of this embodiment, after the above-mentioned joining, the core shaft 10 is removed from a portion distal to a predetermined position between the distal end 36d and the proximal end 36p of the joint 36. In the method for manufacturing the guidewire 100 of this embodiment, a configuration can be realized in which the core shaft 10 extends up to the distal end of the joint 36 (distal tip 30), and the length of the portion where the core shaft 10 and the distal tip 30 are in close contact with each other can be increased, thereby increasing the tensile strength of the guidewire 100.

[0054] In the manufacturing method of the guidewire 100 of this embodiment, after the above-described joining, the coil 20 is removed from a portion distal to a predetermined position between the distal end 36d and the proximal end 36p of the joint 36. In the manufacturing method of the guidewire 100 of this embodiment, the distal end of the coil 20, which is prone to poor joining, is removed, thereby preventing poor joining between the coil 20 and the joint 36 (distal tip 30). For example, even if the surface of the coil 20 is plated to improve wettability, the surface of the distal end 20d of the coil 20 is not plated. Even in such a case, the portion including the surface of the distal end 20d of the coil 20 is removed during manufacturing of the guidewire 100, preventing poor joining due to the absence of plating on the surface of the distal end 20d of the coil 20.

[0055] In the manufacturing method of the guidewire 100 of this embodiment, during the joining, the distal end 10d of the core shaft 10 is located further distal than the distal end 36d of the joint 36 to be formed. In the manufacturing method of the guidewire 100 of this embodiment, the core shaft 10 is joined to the joint 36 on the proximal end side of the distal end of the core shaft 10, which makes it possible to suppress the occurrence of poor joining between the core shaft 10 and the joint 36 (distal tip 30).

[0056] In the manufacturing method of the guidewire 100 of this embodiment, during the above-mentioned joining, the distal end 20d of the coil 20 is located further distal than the distal end 36d of the joint 36 to be formed. In the manufacturing method of the guidewire 100 of this embodiment, the coil 20 is joined to the joint 36 on the proximal side of the distal end of the coil 20, thereby making it possible to suppress the occurrence of poor joining between the coil 20 and the joint 36 (distal tip 30).

[0057] (Second embodiment) 5 is an explanatory diagram showing the configuration of a longitudinal cross section (YZ cross section) of a guidewire 100a according to the second embodiment. In the following, among the configuration of the guidewire 100a according to the second embodiment, the same configuration as that of the guidewire 100 according to the first embodiment described above will be denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0058] The guidewire 100a of the second embodiment has an outer layer coil 70 and an inner layer coil 60 instead of the coil 20 of the guidewire of the first embodiment.

[0059] The inner layer coil 60 is a hollow cylindrical member in which one or more wires are wound in a spiral shape. The core shaft 10 is inserted into the hollow portion of the inner layer coil 60. In this embodiment, the inner layer coil 60 is arranged so as to surround a part of the small diameter portion 11 and a part of the tapered portion 13 of the core shaft 10. In this embodiment, the distal end 60d of the inner layer coil 60 is located closer to the base end than the distal end 10d of the core shaft 10. The inner layer coil 60 is joined to the core shaft 10 by the distal tip 30, the first intermediate joint portion 31, and the first proximal joint portion 35.

[0060] The outer layer coil 70 is a hollow cylindrical member in which one or more wires are wound in a spiral shape. The inner layer coil 60 and the core shaft 10 are inserted into the hollow portion of the outer layer coil 70. In this embodiment, the outer layer coil 70 is disposed so as to surround a part of the small diameter portion 11, the tapered portion 13, and a part of the large diameter portion 12 of the core shaft 10, and to surround a portion of the inner layer coil 60 excluding the distal end portion. The outer layer coil 70 is joined to the core shaft 10 by the distal tip 30, the first intermediate joint portion 31, the second intermediate joint portion 32, and the second base end joint portion 34. In this embodiment, the coil pitch of the outer layer coil 70 is substantially constant throughout.

[0061] For example, metals are used as the material for forming the inner layer coil 60 and the outer layer coil 70. More specifically, radiotransparent materials such as stainless steel (SUS302, SUS304, SUS316, etc.), Ni-Ti alloys, and piano wire, and radiopaque materials such as platinum, gold, tungsten, and alloys thereof are used.

[0062] Materials used to form the distal tip 30, the first intermediate joint 31, the second intermediate joint 32, the first base end side joint 35 and the second base end side joint 34 include, for example, metal solder (Au-Sn alloy, Sn-Ag alloy, Sn-Pb alloy, Pb-Ag alloy, etc.), brazing material (aluminum alloy brazing, silver brazing, gold brazing, etc.), adhesive (epoxy adhesive, etc.), etc.

[0063] In this embodiment, the inner layer coil 60 has a first region 61 and a second region 62. The first region 61 is a region where the coil pitch is a first pitch P1. The second region 62 is located more distally than the first region 61 and where the coil pitch is a second pitch P2, which is wider than the first pitch P1. The second pitch P2 is, for example, 1.5 to 10 times the first pitch P1. The second pitch P2 may be 1.7 to 8 times the first pitch P1, or 2 to 5 times the first pitch P1. In this embodiment, the position of the boundary between the first region 61 and the second region 62 substantially coincides with the position of the base end 30p of the distal tip 30. In other words, the entire first region 61 is located proximal to the base end 30p of the distal tip 30, and the entire second region 62 is located distal to the base end 30p of the distal tip 30. In the axial direction of the guidewire 100a, the position of the proximal end 62p of the second section 62 is the same as the position of the proximal end 30p of the distal tip 30.

[0064] The guidewire 100a of the second embodiment can be manufactured by the same method as the above-described method for manufacturing the guidewire 100 of the first embodiment. That is, the guidewire 100a of the second embodiment can be manufactured by joining the inner layer coil 60 and the core shaft 10 by the method shown in Figures 3 and 4, and then joining the outer layer coil 70 and the core shaft 10 simultaneously with or in a separate step from the joining.

[0065] As described above, the guidewire 100a of the second embodiment includes the core shaft 10, the distal tip 30, the inner layer coil 60, and the outer layer coil 70 arranged outside the inner layer coil 60. The core shaft 10 is inserted into the inner layer coil 60. The inner layer coil 60 is joined to the distal tip 30. The inner layer coil 60 has a first region 61 located proximally of the proximal end 30p of the distal tip 30 and having a coil pitch of a first pitch P1, and a second region 62 located distally of the proximal end 30p of the distal tip 30 and having a coil pitch of a second pitch P2 wider than the first pitch P1. In the second embodiment of the guide wire 100a, the second portion 62 in which the coil pitch in the inner layer coil 60 is relatively wide is located further distal than the base end 30p of the distal tip 30, so that the distal tip 30 is firmly joined to the inner layer coil 60 at the second portion 62, thereby increasing the joining strength between the inner layer coil 60 and the distal tip 30.

[0066] (Variation) The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified in various forms without departing from the spirit thereof, for example, the following modifications are also possible.

[0067] The configuration of the guidewire in the above-described embodiment is merely an example, and various modifications are possible. For example, in the above-described first embodiment, the position of the proximal end 22p of the second portion 22 of the coil 20 may be closer to the distal end than the proximal end 30p of the distal tip 30, or closer to the proximal end than the proximal end 30p of the distal tip 30. In the above-described first embodiment, the position of the distal end 10d of the core shaft 10 may be equal to the position of the distal end 20d of the coil 20, or closer to the proximal end than the position of the distal end 20d of the coil 20.

[0068] In the second embodiment, the outer layer coil 70 may have a first section located proximal to the base end 30p of the distal tip 30 and having a first coil pitch, and a second section located distal to the base end 30p of the distal tip 30 and having a second coil pitch wider than the first pitch. In this case, the inner layer coil 60 may have another configuration, for example, a configuration having a constant coil pitch over its entire length.

[0069] The manufacturing method of the guidewire in the above embodiment is merely an example and various modifications are possible. For example, in the above embodiment, a coil having a first portion having a coil pitch of a first pitch P1 and a second portion having a coil pitch of a second pitch P2 may be prepared from the beginning. In the above embodiment, at least one of the step of removing a portion of the joint 36 and the like and the step of polishing the joint 36 may be omitted.

[0070] In the above embodiment, a joining method other than soldering (for example, brazing or adhesive bonding) may be used to join the core shaft and the coil.

[0071] The technology disclosed in this specification is not limited to guidewires, but is similarly applicable to medical devices in general that are inserted into biological lumens.

Claims

1. A medical device (100), comprising: A core shaft (10), a distal tip (30) joined to the core shaft (10); a coil (20, 60) into which the core shaft (10) is inserted and which is joined to the distal tip (30), the coil (20, 60) including a first portion (21, 61) located on the proximal side of the proximal end of the distal tip (30) and having a coil pitch of a first pitch (P1); and a second portion (22, 62) located on the distal side of the proximal end of the distal tip (30) and having a coil pitch of a second pitch (P2) wider than the first pitch (P1); a coil (20, 60) having A medical device (100) comprising:

2. 10. The medical device (100) of claim 1, A medical device (100) in which, in the axial direction of the medical device (100), the position of the tip of the core shaft (10) is either further forward than the position of the tip of the coil (20, 60), or is equal to the position of the tip of the coil (20, 60).

3. 3. A medical device (100) according to claim 1 or claim 2, A medical device (100), wherein the second pitch (P2) of the coil (20, 60) is 1.5 times or more the first pitch (P1).

4. A medical device (100) according to any one of claims 1 to 3, A medical device (100) wherein at least a portion of the coil (20, 60) is radiopaque.

5. A medical device (100) according to any one of claims 1 to 4, A medical device (100) in which at least a portion of the surface of the coil (20, 60) is plated.

6. A medical device (100) according to any one of claims 1 to 5, A medical device (100) in which, in the axial direction of the medical device (100), the position of the base end of the second portion (22, 62) is either further distal than the position of the base end of the distal tip (30), or is equal to the position of the base end of the distal tip (30).

7. A medical device (100) according to any one of claims 1 to 6, A medical device (100), wherein the coil (20) is an outer layer coil (20).

8. A medical device (100) according to any one of claims 1 to 6, The coil (60) is an inner layer coil (60), The medical device (100) comprises an outer layer coil (70) disposed outside the inner layer coil (60).

9. A method for manufacturing a medical device (100), comprising: preparing a coil (20, 60) having a first portion (21, 61) having a coil pitch of a first pitch (P1) and a second portion (22, 62) having a coil pitch of a second pitch (P2) wider than the first pitch (P1); Inserting a core shaft (10) into the coil (20, 60), A method for manufacturing a medical device (100), comprising forming a joint (36) joining the coil (20, 60) and the core shaft (10) in a range including at least one pitch of the second portion (22, 62) of the coil (20, 60).

10. 10. A method for manufacturing a medical device (100) according to claim 9, comprising the steps of: A method for manufacturing a medical device (100), wherein the joining is performed by soldering.

11. A method for manufacturing a medical device (100) according to claim 9 or 10, comprising the steps of: A method for manufacturing a medical device (100), comprising removing a portion of the bonded portion (36) after the bonding.

12. A method for manufacturing a medical device (100) according to any one of claims 9 to 11, comprising the steps of: A method for manufacturing a medical device (100), wherein after the joining, the core shaft (10) is removed on the distal side of a first position between the distal end and the proximal end of the joint portion (36).

13. A method for manufacturing a medical device (100) according to any one of claims 9 to 12, comprising the steps of: A method for manufacturing a medical device (100), wherein after the joining, the coil (20, 60) is removed from a portion distal to a second position between the distal end and the proximal end of the joint (36).

14. A method for manufacturing a medical device (100) according to any one of claims 9 to 13, comprising the steps of: A method for manufacturing a medical device (100), wherein, during the joining, the tip of the core shaft (10) is located more distal than the tip of the joint portion (36) to be formed.

15. A method for manufacturing a medical device (100) according to any one of claims 9 to 14, comprising the steps of: A method for manufacturing a medical device (100), wherein, during the joining, the tip of the coil (20) is located more distal than the tip of the joint (36) to be formed.

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