Medical device

Abstract

To provide a guide wire capable of suppressing irreversible reforming at a tip of a coil body and inhibiting an element wire constituting the coil body from making positional deviation in a radial direction.SOLUTION: A medical device 1 includes: a core shaft 11; an outside coil body 21 formed by winding an element wire w1; and a tip fastening part 41 where the tip of the core shaft 11 and the outside coil body 21 are fastened to each other. The outside coil body 21 includes a loosely-wound part 21A having gaps in the part of the element wires w1 and w1 adjacent to each other along a long axis direction of the core shaft 11. The loosely-wound part 21A of the outside coil body 21 satisfies the following formulas (1) and (2): (1) 3.5≤D / d≤6.5 and (2) 1<Pa≤3 In the formulas (1) and (2), D represents an effective diameter of the outside coil body 21, d represents an element wire diameter of the outside coil body 21, and Pa represents a representative value of a pitch of the element wire w1 of the outside coil body 21.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] For example, when treating a lesion occurring within a blood vessel, a guidewire is inserted prior to the insertion of a medical instrument such as a catheter in order to guide the instrument.

[0003] As such a guidewire, for example, one has been proposed in which a coil body is arranged to cover the tip of a reduced-diameter core shaft in order to follow complexly curved blood vessels and transmit a rotational force applied to the base end to the tip (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-146390 Summary of the Invention [Problem to be solved by the invention]

[0005] The tip of the guidewire as described above may be pre-formed into a desired shape so that it can be reliably inserted into a desired blood vessel among complexly curved blood vessels or branching blood vessels.

[0006] However, during repeated molding of the tip of the guidewire to accommodate the various shapes of blood vessels, the coil body undergoes plastic deformation, and its shape tends to become skewed or some of the wires that make up the coil body tend to become displaced in the radial direction.

[0007] In a guide wire in which such a coil body is plastically deformed, when attempting to reshape it again, it becomes difficult to form it into a desired shape, or there is a risk that a part of the wire forming the coil body will shift radially and a step will occur on the outer periphery of the guide wire.

[0008] The present invention has been made based on the above circumstances, and an object thereof is to provide a guide wire capable of suppressing irreversible kinking at the tip of the coil body and suppressing the radial misalignment of the wires forming the coil body.

Means for Solving the Problems

[0009] Some aspects of the present disclosure are (1) a core shaft, an outer coil body provided so as to cover at least a part of the tip of the core shaft and formed by winding wires, a tip fixing portion in which the tip of the core shaft and the tip of the outer coil body are fixed to each other, and is a medical device comprising the outer coil body includes a sparsely wound portion having a gap in a portion of adjacent wires along the long axis direction of the core shaft, the sparsely wound portion of the outer coil body satisfies the following formulas (1) and (2), and is a medical device characterized in that 3.5 ≦ D / d ≦ 6.5 ···(1) 1 < Pa ≦ 3 ···(2) (In the formula (1), D represents the effective diameter of the outer coil body, and d represents the wire diameter of the outer coil body. In the formula (2), Pa represents a representative value of the pitch of the wires in the outer coil body.) (2) The medical device according to (1) above, wherein the representative value Pa of the pitch satisfies 1 < Pa ≦ 2 (3) The medical device according to (2) above, wherein the effective diameter D of the outer coil body and the wire diameter d of the outer coil body satisfy 4.5 ≦ D / d ≦ 5 (4) The effective diameter D of the outer coil body and the wire diameter d of the outer coil body satisfy 5 ≦ D / d ≦ 5.5, the medical device according to (2) above, (5) The representative value Pa of the pitch satisfies 1 < Pa ≦ 1.5, the medical device according to any one of (2) to (4) above, (6) The representative value Pa of the pitch satisfies 1 < Pa ≦ 1.1, the medical device according to (5) above, (7) The tip of the sparse winding part is located at the tip of the outer coil body, and the base end of the sparse winding part is located at a position 10 mm to 30 mm from the tip of the outer coil body toward the base end side, the medical device according to any one of (1) to (6) above, (8) Further comprising an inner coil body that covers at least a part of the tip of the core shaft and is disposed inside the outer coil body and is formed by winding a wire at a constant pitch, the medical device according to any one of (1) to (7) above, (9) The winding direction of the wire in the outer coil body and the winding direction of the wire in the inner coil body are opposite to each other, and the inclination angle of the wire in the outer coil body with respect to the long axis of the core shaft and the inclination angle of the wire in the inner coil body with respect to the long axis of the core shaft are different, the medical device according to (8) above, (10) While fixing the tip fixing part, the base end of the core shaft is twisted 3 turns in the circumferential direction, then the fixing of the tip fixing part is released, and the outer coil body is taken out and measured. The bending angle of the tip part of the outer coil body with respect to the long axis tip direction is 180 degrees or less, the medical device according to any one of (1) to (9) above, (11) The medical device according to (10) above, wherein the bending angle is 90 degrees or less, and (12) The medical device according to (11) above, wherein the bending angle is 45 degrees or less.

[0010] In this specification, the term "effective diameter" refers to a value expressed by the outer diameter of the coil body minus (radius of the coil body wires × 2). The term "distal side" refers to a direction along the longitudinal axis of the medical device (guide wire) and a direction in which the wire is inserted deeper (distal) into the body cavity. The term "base end side" refers to a direction along the longitudinal axis of the medical device and a direction opposite to the "distal side". The term "distal" refers to an end on the distal side of any member or part, and the term "base end" refers to an end on the proximal side of any member or part. The term "distal portion" refers to a portion of any member or part that includes the distal end and extends from the distal end to the midpoint of the longitudinal direction from the proximal end. The term "base end portion" refers to a portion of any member or part that includes the proximal end and extends from the proximal end to the midpoint of the longitudinal direction from the proximal end to the distal end. The term "radial direction" refers to a radial direction perpendicular to the longitudinal axis of the core shaft. The term "representative pitch" refers to an index indicating the degree of pitch of the wires constituting the outer coil body in the longitudinal axis direction of the core shaft. Effect of the Invention

[0011] The present invention can provide a guidewire that can suppress irreversible deformation at the tip portion and suppress radial displacement of the wire that constitutes the coil body. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a first embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing an enlarged portion of FIG. [Diagram 3] FIG. 4 is a schematic cross-sectional view showing an enlarged view of a portion of the second embodiment. [Figure 4A] FIG. 1 is an explanatory diagram showing a test method for a crease test. [Figure 4B] 1 is a photograph showing an example of a habit forming test. [Diagram 5] FIG. 1 is an explanatory diagram showing a measurement method for a deformation test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The medical device of the present disclosure is a medical device comprising a core shaft, an outer coil body formed by winding wire and arranged to cover at least a portion of the tip of the core shaft, and a tip fixation portion in which the tip of the core shaft and the tip of the outer coil body are fixed to each other, wherein the outer coil body has an open winding portion having a gap between adjacent portions of the wire along the longitudinal axis of the core shaft, and the open winding portion of the outer coil body satisfies the above formulas (1) and (2).

[0014] Hereinafter, the first and second embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments shown in the drawings. The dimensions of each part shown in the drawings are shown to facilitate understanding of the implementation contents, and do not necessarily correspond to the actual dimensions. In the first and second embodiments shown below, a guidewire will be exemplified as a medical device and described.

[0015] [First embodiment] 1 and 2 are schematic cross-sectional views showing a first embodiment. As shown in Fig. 1 and Fig. 2, a guidewire 1 is generally composed of a core shaft 11, an outer coil body 21, a distal end fixing portion 41, and a proximal end fixing portion 51.

[0016] 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 side.

[0017] The core shaft 11 of this embodiment is configured in the order of a first columnar section 111, a first tapered section 112, a second columnar section 113, a second tapered section 114, and a third columnar section 115 from the tip. The first columnar section 111 is a section having a constant cross section shape (for example, a flat shape). The first tapered section 112 is a tapered section extending from the base end of the first columnar section 111 toward the base end side. The second columnar section 113 is a section having a constant cross section shape (for example, a flat shape) extending from the base end of the first tapered section 112 toward the base end side. The second tapered section 114 is a tapered section (for example, a truncated cone shape) extending from the base end of the second columnar section 113 toward the base end side. The third columnar section 115 is a section having a constant cross section shape (for example, cylindrical) that extends from the base end toward the base end side of the second tapered section 114. At the boundaries between adjacent sections among the first columnar section 111, the first tapered section 112, the second columnar section 113, the second tapered section 114, and the third columnar section 115, the outer shapes of the adjacent sections are configured to be the same and continuous with each other.

[0018] 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.

[0019] The outer coil body 21 is provided so as to cover at least a part of the tip of the core shaft 11, and is a helical member formed by winding a wire w1. As the wire w1, one or more solid wires, one or more twisted wires, or a combination of these can be used. Note that a solid wire means one single wire, and a twisted wire means a bundle of wires formed by twisting multiple single wires together in advance.

[0020] The outer coil body 21 has an open winding portion 21A having a gap between adjacent wires w1, w1 along the longitudinal direction of the core shaft 11, and the open winding portion 21A of the outer coil body 21 is configured to satisfy the following equations (1) and (2). 3.5≦D / d≦6.5 (1) 1 < Pa ≤ 3 ···(2) However, in Formula (1), D represents the effective diameter of the outer coil body 21, and d represents the wire diameter of the outer coil body 21. In the above Formula (2), Pa represents the representative value of the pitch of the wire w1 in the outer coil body 21.

[0021] Specific examples of the representative value Pa of the pitch include, for example, the arithmetic mean value of the pitch of the outer coil body 21 in the sparse winding portion 21A, (Pmin + Pmax) / 2d, the average value ΣP / n obtained from each pitch P, and the like. However, Pmin represents the minimum pitch among the pitches P of the outer coil body 21, Pmax represents the maximum pitch among the pitches P of the outer coil body 21, d represents the wire diameter of the outer coil body 21, P represents the pitch in the outer coil body 21, and n represents the number of turns of the wire w1 in the sparse winding portion 21A.

[0022] Here, the representative value Pa of the pitch preferably satisfies 1 < Pa ≤ 2, more preferably satisfies 1 < Pa ≤ 1.5, and even more preferably satisfies 1 < Pa ≤ 1.1. Also, the lower limit of the representative value Pa of the pitch is preferably 1.01 (1.01 ≤ Pa) regardless of the upper limit. By the representative value Pa of the pitch satisfying the above relationship, irreversible kinks at the tip of the outer coil body 21 and the radial misalignment of the wire w1 constituting the outer coil body 21 can be effectively suppressed.

[0023] The effective diameter D of the outer coil body 21 and the wire diameter d of the outer coil body 21 preferably satisfy 4.5 ≤ D / d ≤ 5, and also preferably satisfy 5 ≤ D / d ≤ 5.5. Further, the effective diameter D of the outer coil body 21 and the wire diameter d of the outer coil body 21 preferably satisfy 5.5 ≤ D / d ≤ 6.5. By D / d satisfying at least any one of the above relationships, while suppressing irreversible kinks at the tip of the outer coil body 21, the compatibility with suppressing the occurrence of misalignment is achieved.

[0024] In this embodiment, the tip of the open coiled portion 21A is located at the tip of the outer coil body 21, and the base end of the open coiled portion 21A is located at a position 10 mm to 30 mm from the tip of the outer coil body 21 toward the base end. In other words, the open coiled portion 21A is disposed in a specific range at the tip of the outer coil body 21. This makes it possible to effectively prevent the outer coil body 21 from becoming creased and the wire w1 from shifting in position at the tip of the guidewire 1 to be shaped, and allows the guidewire 1 to be repeatedly shaped (reshaped) into a desired shape.

[0025] Examples of materials that can be used to form the outer coil body 21 include stainless steel such as SUS316; superelastic alloys such as Ni-Ti alloys; and radiopaque metals such as platinum and tungsten.

[0026] The tip fixing portion 41 is a portion where the tip of the core shaft 11 and the tip of the outer coil body 21 are fixed to each other. The shape of the tip fixing portion 41 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.

[0027] Specifically, the tip fixing portion 41 can be formed, for example, by integrally brazing the tip of the core shaft 11 and the tip of the outer coil body 21 via a brazing material, or by melt-molding a portion that was originally the tip of the core shaft 11 and a portion that was originally the tip of the outer 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.

[0028] The base end fixing portion 51 is a portion where the outer peripheral surface s of the core shaft 11 and the base end of the outer coil body 21 are fixed to each other. The base end fixing portion 51 may be provided at any position on the outer peripheral surface s of the core shaft 11. In this embodiment, the base end fixing portion 51 is provided on the outer peripheral surface s of the third columnar portion 115.

[0029] Specifically, the base end fixing portion 51 can be formed, for example, by brazing the outer peripheral surface s of the core shaft 11 and the base end portion of the outer coil body 21 with a brazing material or by bonding them with an adhesive. Examples of the brazing material include the brazing material used in forming the tip fixing portion 41. Examples of the adhesive include an epoxy adhesive, a cyanoacrylate adhesive, an acrylic adhesive, etc.

[0030] Next, a description will be given of a mode of use of the guidewire 1. First, before inserting the guidewire 1 into a blood vessel, the tip of the guidewire 1 is bent (shaped) into a desired shape (for example, a J-shape). Next, the guidewire 1 is inserted into the blood vessel from its tip, and the base end of the guidewire 1 exposed outside the body is manipulated to advance the tip to the site to be treated within the blood vessel.

[0031] 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, various treatments are performed using the medical instrument. Next, after the treatment is completed, the medical instrument is pulled out of the body along the guidewire 1, and the guidewire 1 is removed from the blood vessel.

[0032] It should be noted that, due to the use of the above-mentioned guidewire 1, the distal end of the removed guidewire 1 tends to deform into a different shape from the shape it was initially shaped into. Therefore, when another medical instrument is subsequently used or when the same medical instrument is to be inserted again into a blood vessel, the distal end of the once removed guidewire 1 may be reshaped into a desired shape (which may be a new shape different from the shape it was initially shaped into) and used (reshaped). The reshaped guidewire 1 can be reused, for example, in the same manner as in the above-mentioned procedure for using the guidewire 1.

[0033] As described above, the guidewire 1 (medical device) has the above-mentioned configuration, and therefore it is possible to suppress irreversible curling at the tip of the outer coil body 21 and to suppress radial displacement of the wires w1 constituting the outer coil body 21. As a result, even if the tip of the guidewire 1 is repeatedly shaped, the outer coil body 21 is less likely to curl, and when shaping again, it can be easily and reliably shaped into a desired shape. In addition, since steps are less likely to occur in the outer coil body 21, the guidewire 1 and medical instruments such as a catheter used in combination with the guidewire 1 can be delivered more smoothly to the treatment site.

[0034] The above-mentioned irreversible curling and misalignment of the wires are suppressed for the following reasons.

[0035] That is, when the wire diameter d is large relative to the effective diameter D of the outer coil body, the relative shear force in the transverse direction of the wire increases, and the wire is more likely to become deformed due to the accumulation of internal stress. On the other hand, when the wire diameter d is small relative to the effective diameter D of the outer coil body, the wire is more likely to move radially and become displaced.

[0036] Furthermore, when the representative value Pa of the pitch of the wires in the outer coil body is increased, the inherent flexibility of the coil body is improved, so that the wires are less likely to become plastically distorted when the outer coil body is bent (formed). When the representative value Pa of the pitch of the wires in the outer coil body is increased, the degree of freedom in the axial direction of the long axis Z1 (see FIG. 3) of the outer coil body is increased, so that the wires of the outer coil body are less likely to move radially and become displaced. On the other hand, when the representative value Pa of the pitch of the wires in the outer coil body is decreased, the space in which the wires can exist is reduced, and as a result, the wires are more likely to become distorted due to the accumulation of internal stress that occurs when the outer coil body is bent, and the wires are more likely to move radially and become displaced.

[0037] Therefore, it is presumed that by giving the guide wire 1 a specific shape that satisfies the relationship between the above-mentioned equations (1) and (2), it is possible to suppress irreversible deformation at the tip of the outer coil body 21 while suppressing radial displacement of the wire w1 that constitutes the outer coil body 21.

[0038] [Second embodiment] Fig. 3 is a schematic cross-sectional view showing the second embodiment. As shown in Fig. 3, the guidewire 2 is generally composed of a core shaft 11, an outer coil body 21, an inner coil body 32, a distal end fixing portion 41, and proximal end fixing portions 51 and 52. The guidewire 2 differs from the first embodiment in that it further includes an inner coil body 32. Note that the configurations other than the configuration of the inner coil body 32 shown below are the same as those of the first embodiment, and therefore the same parts are denoted by the same reference numerals and detailed description thereof will be omitted. The usage of the guidewire 2 is also the same as that of the first embodiment.

[0039] The inner coil body 32 is a spiral member that covers at least a portion of the tip end of the core shaft 11, is disposed inside the outer coil body 21, and is formed by winding a wire w2 at a constant pitch. As the wire w2, for example, one or more solid wires, one or more twisted wires, or a combination of these can be used.

[0040] Examples of materials that can be used to form the inner coil body 32 include stainless steel such as SUS316; superelastic alloys such as Ni-Ti alloys; and radiopaque metals such as platinum and tungsten.

[0041] The inner coil body 32 can have, for example, a tip end integrally fixed to the core shaft 11 and the outer coil body 21 at the tip fixing portion 41, and a base end fixed to any outer circumferential surface s of the core shaft 11. The inner coil body 32 in this embodiment has a tip end fixed at the tip fixing portion 41, and a base end fixed to the outer circumferential surface s of the second tapered portion 114 of the core shaft 11. As a method for fixing the inner coil body 32 at the tip fixing portion 41 and the base end fixing portion 52, for example, a method similar to the fixing method at the tip fixing portion 41 and the base end fixing portion 51 of the outer coil body 21 described above, respectively, can be adopted.

[0042] Here, the winding direction of the wire w1 in the outer coil body 21 and the winding direction of the wire w2 in the inner coil body 32 may be opposite to each other, and the inclination angle θ1 of the wire w1 in the outer coil body 21 relative to the long axis z1 of the core shaft 11 and the inclination angle θ2 of the wire w2 in the inner coil body 32 relative to the long axis z1 of the core shaft 11 may be different (see Figure 3).

[0043] That is, the outer coil body 21 and the inner coil body 32 may be configured so that one of them is S-twisted and the other is Z-twisted, and the winding angle θ1 of the outer coil body 21 relative to the tip direction of the long axis z1 of the core shaft 11 is different from the winding angle θ2 of the inner coil body 32 relative to the tip direction of the long axis z1 of the core shaft 11. This makes it possible to more effectively prevent the strands of one coil body (e.g., the outer coil body 21) from entering the gaps between adjacent strands of the other coil body (e.g., the inner coil body 32).

[0044] As described above, since the guidewire 2 (medical device) includes the inner coil body 32, it is possible to suppress radial displacement of the wires w1 constituting the outer coil body 21.

[0045] 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.

[0046] For example, in the above-described embodiment, the guidewire 1 (medical device) has been described in which the outer coil body 21 has the openly wound portion 21A and the densely wound portion 21B. However, the outer coil body 21 may be composed of only the openly wound portion 21A without having the densely wound portion 21B.

[0047] In the above-described embodiment, the guidewires 1, 2 (medical devices) have been described in which the openly coiled portion 21A is located at the distal end of the outer coil body 21. However, the openly coiled portion 21A may be located midway in the longitudinal direction of the outer coil body or at the proximal end.

[0048] In the above-described embodiment, the guidewires 1, 2 (medical devices) have been described in which the open coiled portion 21A is provided only at one location on the outer coil body 21. However, the open coiled portion 21A may be provided at two or more independent locations on the outer coil body.

[0049] In the above-described embodiment, the guidewires 1 and 2 have been described in which the core shaft 11 is configured in the following order from the tip: first columnar section 111, first tapered section 112, second columnar section 113, second tapered section 114, and third columnar section 115. However, the shape of the core shaft is not particularly limited. For example, the core shaft may not have a tapered section, and may be configured only with a tapered section.

[0050] <Experimental Results> The specifications of the medical device (guidewire) used for evaluation are shown in Table 1. Other specifications are as follows. The representative pitch value Pa for each sample is determined by using the value Pa = (Pmin + Pmax) / 2d, where Pmin represents the minimum pitch among the pitches of the outer coil body, Pmax represents the maximum pitch among the pitches of the outer coil body, and d represents the wire diameter of the outer coil body. The tip of the open coil portion in each sample is located at the tip of the outer coil body, and the length of the open coil portion in Table 1 indicates the length from the tip to the base end of the open coil portion.

[0051] [Outer coil body] ·Material: Pt-Ni alloy Coil effective diameter D: 0.36mm-(d / 2×2) Coil outer diameter: 0.36mm Wire diameter d: See Table 1 · Representative pitch value Pa: See Table 1 Length of open winding: See Table 1 [Inner coil body] Material: Stainless steel Coil outer diameter: 0.2mm Wire diameter: 0.025mm

[0052] <Evaluation> The guidewires shown in Table 1 were used to evaluate their resistance to crease and displacement according to the following methods. The results are also shown in Table 1.

[0053] [Habitual inhibition] While fixing the tip fixing part of the guidewire to be used in the test (crease test), the base end of the core shaft was twisted 3 times in the circumferential direction, and then the tip fixing part was released and the outer coil body was removed and measured. At this time, the degree of bending (bending angle) of the tip of the outer coil body relative to the long axis tip direction was measured, and this measurement value was used as an index to evaluate the crease prevention ability.

[0054] Specifically, as shown in FIG. 4A(a), the guidewire to be tested was inserted from one opening 91a of a transparent silicone tube 91 having an inner diameter of 1.25 mm, and the tip of the guidewire was fixed to the silicone tube 91 through a hole 91b. Next, as shown in FIG. 4A(b), the guidewire was twisted three times in the circumferential direction with respect to the silicone tube 91. FIG. 4B is an external photograph showing an example of the guidewire after being twisted three times in the circumferential direction. Next, the fixation of the tip of the guidewire was released and taken out of the silicone tube 91. Next, the guidewire was disassembled to take out the outer coil body, and the angle (bending angle θ3) at which the tip of the outer coil body (21) was bent with respect to the major axis z2 of the outer coil body (21) (the same as the longitudinal axis of the outer coil body before the test) was measured as shown in FIG.

[0055] In this case, when the bending angle θ3 is 180 degrees or less, the ability to suppress the formation of a habit is evaluated as good, and when the bending angle θ3 is greater than 180 degrees, the ability to suppress the formation of a habit is evaluated as poor. In addition, when the bending angle θ3 is 90 degrees or less, the ability to suppress the formation of a habit is evaluated as even better, and when the bending angle θ3 is 45 degrees or less, the ability to suppress the formation of a habit is evaluated as best.

[0056] [Prevention of misalignment] Using the outer coil body after the evaluation of the above-mentioned ability to suppress crease, a stereoscopic image was observed under a microscope at a magnification of 20. During this observation, the number of misaligned points (points that were clearly recognized as being misaligned) per outer coil body was counted, and the misalignment suppression ability was evaluated using this number as an index.

[0057] [Table 1]

[0058] As can be seen from the results in Table 1, for No. 1 to No. 29, the representative pitch value Pa was greater than 1, and therefore the positional displacement suppression was good. The effective diameter D of the outer coil body 21 / strand diameter d of the outer coil body 21 is preferably 4.5 or more and 5.5 or less. The effective diameter D of the outer coil body 21 / strand diameter d of the outer coil body 21 is preferably 4.5 or more and 5 or less. This is because a smaller effective diameter D makes it easier to apply to a guidewire with a small maximum outer diameter. It is also preferable that the effective diameter D of the outer coil body 21 / strand diameter d of the outer coil body 21 is 5 or more and 5.5 or less. This is because the bending angle is suppressed. [Explanation of symbols]

[0059] 1,2 Medical Devices (Guidewires) 11 Core shaft 21 Outer coil body 21A Loosely wound part 32 Inner coil body 41 Tip fixation part D Effective diameter of outer coil body d Outer coil wire diameter Pa Typical pitch θ1,θ2 Tilt angle θ3 Bending angle z2 Long axis of the outer coil body

Claims

1. Core shaft and An outer coil body is provided so as to cover at least a portion of the tip of the core shaft and is formed by winding strands of wire, A medical device comprising a tip fixing portion in which the tip of the core shaft and the tip of the outer coil body are fixed to each other, The outer coil body comprises loosely wound portions having gaps between adjacent strands along the longitudinal axis of the core shaft, The loosely wound portion of the outer coil body is characterized in that it satisfies the following formulas (1) and (2). 3.5 ≤ D / d ≤ 6.5 ... (1) 1 < Pa ≤ 3 ... (2) (In formula (1), D represents the effective diameter of the outer coil body, and d represents the wire diameter of the outer coil body. In formula (2), Pa represents a typical value of the wire pitch in the outer coil body.)

2. The medical device according to claim 1, wherein the representative value Pa of the pitch satisfies 1 < Pa ≤ 2.

3. The medical device according to claim 2, wherein the effective diameter D of the outer coil body and the wire diameter d of the outer coil body satisfy 4.5 ≤ D / d ≤ 5.

4. The medical device according to claim 2, wherein the effective diameter D of the outer coil body and the wire diameter d of the outer coil body satisfy 5 ≤ D / d ≤ 5.

5.

5. The medical device according to any one of claims 2 to 4, wherein the representative value Pa of the pitch satisfies 1 < Pa ≤ 1.

5.

6. The medical device according to claim 5, wherein the representative value Pa of the pitch satisfies 1 < Pa ≤ 1.

1.

7. The medical device according to any one of claims 1 to 4, wherein the tip of the loosely wound portion is located at the tip of the outer coil body, and the base end of the loosely wound portion is located 10 mm to 30 mm from the tip of the outer coil body toward the base end.

8. The medical device according to any one of claims 1 to 4, further comprising an inner coil body that covers at least a portion of the tip of the core shaft and is disposed inside the outer coil body, and is formed by winding strands at a constant pitch.

9. The medical device according to claim 8, wherein the winding direction of the wires in the outer coil body and the winding direction of the wires in the inner coil body are opposite to each other, and the inclination angle of the wires in the outer coil body with respect to the long axis of the core shaft is different from the inclination angle of the wires in the inner coil body with respect to the long axis of the core shaft.

10. The medical device according to any one of claims 1 to 4, wherein the base end of the core shaft is twisted three times in the circumferential direction while the tip fixing portion is fixed, the fixing of the tip fixing portion is released, and the outer coil body is removed and measured, the bending angle of the tip of the outer coil body with respect to the longitudinal tip direction is 180 degrees or less.

11. The medical device according to claim 10, wherein the bending angle is 90 degrees or less.

12. The medical device according to claim 11, wherein the bending angle is 45 degrees or less.

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