Medical device

Abstract

To provide a medical device that enables a proximal fixation part to have features that are difficult to attain using brazing.SOLUTION: A medical device includes a core shaft 11, a coil body 21 wound around so as to cover the core shaft 11, and a proximal fixation part 41 where the core shaft 11 and the proximal part of the coil body 21 are fixed. The proximal fixation part 41 includes a first adhesive 411 that bonds the core shaft 11 to the coil body 21, and a second adhesive 412 that is disposed so as to cover at least a portion of an outer periphery of the first adhesive 411 and differs from the first adhesive 411 in terms of at least one physical characteristic value.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to medical devices. [Background technology]

[0002] For example, when using a medical instrument such as a balloon catheter for treating a lesion in a blood vessel, a medical device such as a guide wire for guiding the medical instrument is inserted in advance into the blood vessel or the like.

[0003] The above-mentioned medical device is required to have, for example, excellent flexibility so that it can move smoothly through curved blood vessels, and high torque transmissibility so that rotational operations at the hand can be reliably transmitted to the tip. As a medical device with improved flexibility and torque transmissibility, for example, a medical device in which a coil body is arranged around the tip of a core shaft has been proposed (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2010-524588 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional medical devices as described above, the core shaft and the base end of the coil body are usually joined (fixed) by brazing. The present invention has been made in view of the above circumstances, and has an object to provide a medical device capable of imparting a function to the base end fixing part that is difficult to obtain by brazing. [Means for solving the problem]

[0006] Some aspects of the present disclosure include: (1) a core shaft; a coil body wound so as to cover the core shaft; a base end fixing portion to which the core shaft and a base end portion of the coil body are fixed, The base end fixing portion is a first adhesive that bonds the core shaft and the coil body; a second adhesive disposed so as to cover at least a portion of the outer periphery of the first adhesive, the second adhesive having at least one physical property different from that of the first adhesive; (2) The medical device according to (1), wherein the at least one physical property value is a physical property value indicating a mechanical property. (3) the at least one physical property value includes elastic modulus; The medical device according to (2), wherein the elastic modulus value of the second adhesive is smaller than the elastic modulus value of the first adhesive; (4) The at least one physical property value includes a breaking strain; The medical device according to (2) or (3), wherein the breaking strain value of the second adhesive is greater than the breaking strain value of the first adhesive; (5) The at least one physical property value includes a breaking stress, The medical device according to any one of (2) to (4), wherein the second adhesive has a breaking stress value smaller than the breaking stress value of the first adhesive; (6) The medical device according to any one of (1) to (5), wherein the second adhesive covers a tip portion of the first adhesive. (7) The medical device according to any one of (1) to (6), wherein the second adhesive covers a rear end of the first adhesive. (8) The medical device according to any one of (1) to (7), wherein the first adhesive comprises at least one selected from the group consisting of an epoxy adhesive, a cyanoacrylate adhesive, and an acrylic adhesive. (9) The medical device according to any one of (1) to (8), wherein the second adhesive comprises at least one selected from the group consisting of a urethane-based adhesive, a polyester-based adhesive, and a silicone-based adhesive. (10) The medical device according to any one of (1) to (9), wherein the second adhesive covers at least a portion of the outer periphery of the coil body. (11) The medical device according to (10), wherein the second adhesive covers 10% or more of the length of the coil body in the longitudinal direction of the core shaft; and (12) The second adhesive is the medical device described in (11) above, which covers the tip of the medical device.

[0007] In this specification, the term "tensile strength" refers to the "tensile adhesive strength" defined in JIS K6849-1994 "Test method for tensile adhesive strength of adhesives." The term "elastic modulus" refers to the elastic modulus measured, for example, by an indentation test. Effect of the Invention

[0008] The present invention can provide, for example, a medical device that can impart a function to the base end fixing portion that is difficult to obtain by brazing. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an entire embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing an enlarged portion of FIG. [Figure 3A] FIG. 2 is a schematic cross-sectional view showing an enlarged proximal fixing portion, illustrating an example of the arrangement of the first and second adhesives. [Figure 3B] FIG. 2 is a schematic cross-sectional view showing an enlarged proximal fixing portion, illustrating an example of the arrangement of the first and second adhesives. [Figure 3C] FIG. 2 is a schematic cross-sectional view showing an enlarged proximal fixing portion, illustrating an example of the arrangement of the first and second adhesives. [Figure 3D] FIG. 2 is a schematic cross-sectional view showing an enlarged proximal fixing portion, illustrating an example of the arrangement of the first and second adhesives. [Figure 3E] FIG. 2 is a schematic cross-sectional view showing an overall arrangement of a first and second adhesive agent. [Figure 3F]FIG. 2 is a schematic cross-sectional view showing an overall arrangement of a first and second adhesive agent. [Figure 3G] FIG. 2 is a schematic cross-sectional view showing an enlarged proximal fixing portion, illustrating an example of the arrangement of the first and second adhesives. [Figure 4] FIG. 2 is a schematic diagram illustrating the relationship between strain and stress in one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The medical device of the present disclosure is a medical device comprising a core shaft, a coil body wound to cover the core shaft, and a base end fixation portion to which the core shaft and the base end portion of the coil body are fixed, the base end fixation portion having a first adhesive that bonds the core shaft and the coil body, and a second adhesive that is arranged to cover at least a portion of the outer periphery of the first adhesive and has at least one physical property value different from that of the first adhesive.

[0011] In this specification, the term "distal side" refers to the direction along the longitudinal axis of the medical device in which the distal fixation part is located relative to the proximal fixation part. The term "proximal side" refers to the direction along the longitudinal axis of the medical device in the opposite direction to the distal side. The term "distal" refers to the distal end of any member or part, and the term "proximal end" refers to the proximal end of any member or part.

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiment shown in the drawings. In the following embodiment, a guidewire will be exemplified as a medical device. The dimensions of each part shown in the drawings are shown to facilitate understanding of the implementation content, and do not necessarily correspond to the actual dimensions. In each figure, the left side of the drawing indicates the tip side (distal) of the guidewire, and the right side indicates the base end side (proximal, hand side) of the guidewire.

[0013] 1 and 2 are schematic diagrams showing one embodiment. As shown in FIG. 1, the guidewire 1 is generally composed of a core shaft 11, a coil body 21, a distal end fixing portion 31, and a proximal end fixing portion 41.

[0014] The core shaft 11 is an elongated member that constitutes the central axis of the guidewire 1. Specifically, for example, the core shaft 11 can be formed so that the diameter of its distal end portion gradually decreases toward the distal end.

[0015] The core shaft 11 of this embodiment is configured in the following order from the tip: small diameter section 11a, tapered section 11b, large diameter section 11c, connecting section 11d, and main body section 11e. The small diameter section 11a is a cylindrical section with a constant outer diameter. The tapered section 11b is extended from the base end of the small diameter section 11a toward the base end side, and is a tapered (frustum-shaped) section whose outer diameter gradually increases from the tip to the base end. The large diameter section 11c is extended from the base end of the tapered section 11b toward the base end side, and is a cylindrical section with a constant outer diameter. The connecting section 11d is extended from the base end of the large diameter section 11c toward the base end side, and is a tapered (frustum-shaped) section whose outer diameter gradually increases from the tip to the base end. The main body section 11e is extended from the base end of the connecting section 11d toward the base end side, and is a cylindrical section with a constant outer diameter. At the boundaries between the above-mentioned portions 11a to 11e, the outer shapes of the portions in contact with each other are configured to be the same and continuous with each other.

[0016] As a material for forming the core shaft 11, from the viewpoint of increasing the flexibility of the guide wire 1 while imparting antithrombotic properties and biocompatibility, for example, stainless steel such as SUS304, superelastic alloys such as Ni-Ti alloys, etc. can be used.

[0017] The coil body 21 is a member wound so as to cover the core shaft 11. Specifically, the coil body 21 can be formed in a spiral shape along the long axis direction so as to cover at least a part of the outer periphery of the core shaft 11. For example, the coil body 21 can be formed into a coil shape by winding a wire, or formed into a coil shape by slitting a cylindrical member. When a wire is used for the coil body 21, one or more solid wires or one or more twisted wires can be used as the winding. However, the solid wire means one single wire, and the twisted wire means a bundle of wires formed by twisting a plurality of single wires together in advance.

[0018] The coil body 21 may be made of, for example, stainless steel such as SUS316; superelastic alloys such as Ni-Ti alloys; radiopaque metals such as platinum and tungsten; or the like.

[0019] The tip fixing portion 31 is a portion for fixing the tip of the core shaft 11 and the tip of the coil body 21 so as to join them together. The shape of the tip fixing portion 31 may be formed so that the tip side is smoothly curved into a semi-spherical shape so as not to damage the inner wall of the blood vessel when the guidewire 1 advances through the blood vessel.

[0020] Specifically, the tip fixing portion 31 can be formed, for example, by integrally brazing the tip of the core shaft 11 and the tip of the coil body 21 via a brazing material, or by melt-molding the portion that was originally the tip of the core shaft 11 and the portion that was originally the tip of the coil body 21. Examples of the brazing material used for brazing include metal brazing materials such as Sn-Pb alloy, Pb-Ag alloy, Sn-Ag alloy, and Au-Sn alloy.

[0021] The base end fixing portion 41 is a portion where the core shaft 11 and the base end portion of the coil body 21 are fixed. The base end fixing portion 41 can be provided, for example, on the outer peripheral surface 11s of the tapered portion 11b, the large diameter portion 11c, the connection portion 11d, the main body portion 11e, etc. of the core shaft 11. The shape of the base end fixing portion 41 may be, for example, a shape in which the thickness gradually decreases from the tip to the base end (for example, a tapered shape, etc.). When the base end fixing portion 41 is tapered, for example, by using a first adhesive 411 described later, the coil body 21 can be fixed to the core shaft 11 more quickly than by using a brazing material, and a base end fixing portion 41 with higher positioning accuracy can be obtained. In this embodiment, the base end fixing portion 41 formed in a tapered shape so that the thickness decreases toward the base end side is provided on the outer peripheral surface 11s of the main body portion 11e.

[0022] As shown in FIG. 2, the base end fixing portion 41 has a first adhesive 411 and a second adhesive 412 .

[0023] The first adhesive 411 is an adhesive that bonds the core shaft 11 and the coil body 21. The first adhesive 411 is formed so as to be in direct contact with both the base end portion of the coil body 21 and the outer circumferential surface 11s of the core shaft 11.

[0024] The second adhesive 412 is an adhesive disposed so as to cover at least a part of the outer periphery of the first adhesive 411. Specific examples of such an adhesive include a configuration in which the second adhesives 412B1 and 412B3 cover the leading ends of the first adhesives 411A1 and 411A3 as shown in Fig. 3A and Fig. 3C, and a configuration in which the second adhesives 412B1 and 412B2 cover the trailing ends of the first adhesives 411A1 and 411A2 as shown in Fig. 3A and Fig. 3B. In this embodiment, the second adhesive 412B1 is disposed so as to cover the entire surface of the first adhesive 411A1 (see Fig. 3A).

[0025] Furthermore, the second adhesive 412 may cover at least a part of the outer periphery of the coil body 21. In such a case, the second adhesive 412 may cover 10% or more of the length of the coil body 21 in the long axis direction of the core shaft 11. Furthermore, the second adhesive 412 may cover the tip of the guidewire 1. Specific examples of these include a configuration in which the second adhesive 412B5 covers the entire outer periphery of the coil body 21 as shown in FIG. 3E, and a configuration in which the second adhesive 412B6 covers the entire outer periphery of the coil body 21 and the tip fixing portion 31 as shown in FIG. 3F.

[0026] The area where the second adhesive 412 is provided may include an area that directly contacts the core shaft 11 and / or the coil body 21. That is, the second adhesive 412B2 may be provided over the surface of the first adhesive 411A2 and the surface 11s of the core shaft 11 (see FIG. 3B), the second adhesive 412B3 may be provided over the surface of the first adhesive 411A3 and the surface of the coil body 21 (see FIG. 3C), and the second adhesive 412B4 may be provided over the surface of the first adhesive 411A4, the surface 11s of the core shaft 11, and the surface of the coil body 21 (see FIG. 3D). In FIG. 2 and FIG. 3A to FIG. 3D, "A" indicates the area where the first adhesive 411 is formed in the long axis direction, and "B" indicates the area where the second adhesive 412 is formed in the long axis direction.

[0027] The second adhesive 412 has at least one physical property value different from the first adhesive 411. For the first adhesive 411, an adhesive having better workability (ease of work such as work time (curing time, etc.) and effort (preparation of adhesive, etc.)) for fixing the core shaft 11 and the coil body 21 can be used compared to the second adhesive 412.

[0028] At least one physical property value that differs between the first adhesive 411 and the second adhesive 412 may be a physical property value indicating a mechanical property.

[0029] Examples of physical property values ​​indicative of the mechanical properties include the tensile strength between the components after the adhesive has hardened, the elastic modulus of the cured adhesive, the breaking strain of the cured adhesive, and the breaking stress of the cured adhesive.

[0030] In this embodiment, the physical property values ​​that differ between the first adhesive 411 and the second adhesive 412 include the tensile strength, elastic modulus, breaking strain, and breaking stress of the cured adhesive.

[0031] Specifically, in this embodiment, the tensile strength of the first adhesive 411 is greater than the tensile strength of the second adhesive 412, and the elastic modulus value of the second adhesive 412 is smaller than the elastic modulus value of the first adhesive 411. Also, in this embodiment, as shown in FIG. 4, the breaking strain value of the second adhesive 412 is greater than the breaking strain value of the first adhesive 411, and the breaking stress value of the second adhesive 412 is smaller than the breaking stress value of the first adhesive 411.

[0032] Examples of the first adhesive 411 include an epoxy adhesive, a cyanoacrylate adhesive, an acrylic adhesive, etc. The first adhesive 411 may be used alone or in combination of two or more kinds. Note that it is preferable to use an adhesive having a shorter hardening time (faster hardening speed) as the first adhesive 411 compared to the second adhesive 412.

[0033] Examples of the second adhesive 412 include thermoplastic elastomers such as urethane adhesives, polyester adhesives, and silicone adhesives. The second adhesive 412 may be used alone or in combination of two or more kinds.

[0034] In this embodiment, the first adhesive 411 is an epoxy-based adhesive and the second adhesive 412 is a urethane-based adhesive. For example, as shown in FIG. 3D, the second adhesive 412B4 is provided so as to cover the first adhesive 411A4, the base end of the coil body 21, and a portion of the surface 11s of the main body portion 11e of the core shaft 11.

[0035] Next, a method for forming the base end fixing part 41 will be described. First, the core shaft 11 and the coil body 21 formed in a predetermined shape are prepared. Next, the coil body 21 is placed on the tip part of the core shaft 11, and then the tip fixing part 31 is formed so that the tip part of the core shaft 11 and the tip part of the coil body 21 are joined. The tip fixing part 31 can be formed by brazing using a brazing material such as an Sn-Pb alloy, a Pb-Ag alloy, an Sn-Ag alloy, or an Au-Sn alloy so that the tip part has a predetermined shape (such as a substantially hemispherical shape with the tip part curved convexly toward the tip direction).

[0036] Next, base end fixing portion 41 is formed so as to join core shaft 11 and the base end of coil body 21. For example, base end fixing portion 41 is formed by positioning the base end of coil body 21 at a predetermined location on core shaft outer circumferential surface 11s using a jig, and then bonding the base end of coil body 21 to outer periphery 11s of core shaft 11 using first adhesive 411. Next, after first adhesive 411 has hardened, second adhesive 412 is applied so as to cover the surface of first adhesive 411 and hardened to form base end fixing portion 41.

[0037] As described above, in the proximal end fixing portion 41 of the guidewire 1 of the present embodiment, the tensile strength of the first adhesive 411 is greater than the tensile strength of the second adhesive 412. Therefore, the greater tensile strength (bonding ability) of the first adhesive 411 can increase the fixing strength between the core shaft 11 and the coil body 21.

[0038] Next, we will explain how to use the guidewire 1. First, the guidewire 1 is inserted into a blood vessel from its tip, and the proximal end of the guidewire 1 exposed outside the body is manipulated to advance the tip to the site to be treated in the blood vessel.

[0039] Next, after the tip of the guidewire 1 reaches the site to be treated, the base end of the guidewire 1 is inserted into the lumen of a medical instrument (not shown) such as a catheter from its tip, and the medical instrument is pushed into the blood vessel along the guidewire 1. Next, after the medical instrument reaches the site to be treated in the blood vessel, various treatments are performed using the medical instrument. Next, after the treatment is completed, the medical instrument and the guidewire 1 are pulled out of the blood vessel, completing the series of procedures.

[0040] As described above, the guidewire 1 has the above-mentioned configuration, and thus, for example, the base end fixing portion can be endowed with a function that is difficult to obtain by brazing. Specifically, for example, the base end fixing portion 41 can be endowed with a multiple function, such as improving the workability of fixing the core shaft 11 and the coil body 21 as well as the reliability of the fixing. Furthermore, by forming the base end fixing portion 41 with the first adhesive 411 and the second adhesive 412, attention needs to be paid mainly to adjusting the viscosity of the adhesive during fixing, and compared to fixing by brazing, which requires attention to many things such as the heating temperature, the amount of flux applied, and the penetration length of the brazing material, it is possible to suppress manufacturing variations in the guidewire that are likely to occur due to the skill of the worker.

[0041] During the operation of the guidewire 1, various forces are applied to the proximal end fixing part 41. Examples of such forces include internal stress accompanying distortion of the proximal end fixing part 41 that occurs when the guidewire 1 is bent intentionally or accidentally, and a pressing force applied from the outside to the proximal end fixing part 41. When such forces are applied to the proximal end fixing part 41, even if the first adhesive 411 is damaged, the guidewire 1 can prevent fragments of the damaged first adhesive 411 from scattering (detaching) to the outside because the first adhesive 411 is covered with the second adhesive 412 having a fracture strain larger than the fracture strain of the first adhesive 412.

[0042] The present disclosure is not limited to the configurations of the above-described embodiments, but is intended to include all modifications within the scope of the claims and meaning equivalent to the scope of the claims. A part of the configurations of the above-described embodiments may be deleted or replaced with another configuration, or another configuration may be added to the configurations of the above-described embodiments.

[0043] For example, in the above-described embodiment, a guidewire has been described as an example of the medical device, but the medical device may be a medical device other than a guidewire.

[0044] In the above-mentioned embodiment, the core shaft 11 having the small diameter portion 11a, the tapered portion 11b, the large diameter portion 11c, the connecting portion 11d, and the main body portion 11e has been described as an example. However, various types of core shafts can be used, such as a core shaft having a constant outer diameter from the tip to the base end, or a core shaft having no connecting portion 11d and in which the large diameter portion and the main body portion are integrated.

[0045] In the above-described embodiment, the coil body 21 is wound once both inside and outside in the radial direction. However, the coil body may be wound twice or more times both inside and outside in the radial direction. The coil body may be single-stranded or multi-stranded. The winding that constitutes the coil body may be solid wire or twisted wire.

[0046] In the above-described embodiment, the base end fixing portion 41 in which the first adhesive 411 and the second adhesive 412 are in contact with each other has been described as an example. However, another member may be interposed between the first adhesive and the second adhesive, or a space may be provided between the first adhesive and the second adhesive.

[0047] In the above-described embodiment, the base end fixing portion 41 is described as having a single region each of the first adhesive 411 and the second adhesive 412. However, for example, the first adhesive and the second adhesive may each be formed of a plurality of separate regions.

[0048] In the above-described embodiment, the guidewire 1 is described by way of example in which the second adhesive 412B1 is provided so as to cover the entire surface of the first adhesive 411A1. However, as shown in FIG. 3G, the second adhesive 412B7 may be provided so as to cover a portion of the surface of the first adhesive 411A7. [Explanation of symbols]

[0049] 1 Guidewire 11 Core shaft 21 Coil body 31 Tip fixation part 41 Proximal fixation part 411, 411A1 to 411A7 First adhesive 412, 412B1~412B7 Second adhesive

Claims

1. A core shaft, a coil body wound so as to cover the core shaft, and a base end fixing portion where the core shaft and the base end portion of the coil body are fixed, a medical device comprising: wherein the base end fixing portion has a first adhesive for adhering the core shaft and the coil body, and a second adhesive disposed so as to cover at least a part of the outer periphery of the first adhesive and having at least one physical property value different from that of the first adhesive, a medical device characterized by this.

2. The medical device according to claim 1, wherein the at least one physical property value is a physical property value indicating a mechanical property.

3. The at least one physical property value includes an elastic modulus, and the value of the elastic modulus of the second adhesive is smaller than the value of the elastic modulus of the first adhesive. The medical device according to claim 2.

4. The at least one physical property value includes a breaking strain, and the value of the breaking strain of the second adhesive is larger than the value of the breaking strain of the first adhesive. The medical device according to claim 2.

5. The at least one physical property value includes a breaking stress, and the value of the breaking stress of the second adhesive is smaller than the value of the breaking stress of the first adhesive. The medical device according to claim 2.

6. The medical device according to claim 1, wherein the second adhesive covers the tip portion of the first adhesive.

7. The medical device according to claim 1, wherein the second adhesive covers the rear end portion of the first adhesive.

8. The medical device according to claim 1, wherein the first adhesive includes at least one selected from the group consisting of an epoxy-based adhesive, a cyanoacrylate-based adhesive, and an acrylic-based adhesive.

9. The medical device according to claim 1, wherein the second adhesive includes at least one selected from the group consisting of a urethane-based adhesive, a polyester-based adhesive, and a silicone-based adhesive.

10. The medical device according to claim 1, wherein the second adhesive covers at least a part of the outer periphery of the coil body.

11. The medical device according to claim 10, wherein the second adhesive covers 10% or more of the length of the coil body in the longitudinal direction of the core shaft.

12. The medical device according to claim 11, wherein the second adhesive covers the tip of the medical device.

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