Medical device

Abstract

The purpose of the present invention is to provide a guide wire that makes it possible to suppress irreversible deformation at a tip end portion of a coil body and to suppress displacement of a wire that forms the coil body in the radial direction.　A medical device 1 comprises: a core shaft 11; an outer coil body 21 formed by winding a wire w1; and a tip end fixed part 41 in which the tip end of the core shaft 11 and the outer coil body 21 are fixed to each other. The outer coil body 21 includes a loosely wound part 21A having gaps between portions of the wires w1, w1 that are adjacent to each other along the long axis direction of the core shaft 11. The loosely wound part 21A of the outer coil body 21 satisfies formulae (1) and (2). In the formulae (1) and (2), D represents the effective diameter of the outer coil body 21, d represents the wire diameter of the outer coil body 21, and Pa represents the representative value of the pitch of the wire w1 of the outer coil body 21.　(1): 3.5 ≤ D / d ≤ 6.5 (2): 1 < Pa ≤ 3

Description

medical devices

[0001] The present invention relates to medical devices.

[0002] For example, when treating a lesion or the like that has occurred in a blood vessel, a guide wire is inserted in advance of a medical instrument such as a catheter 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 rotational force applied to the base end to the tip (see, for example, Patent Document 1).

[0004] Japanese Patent Application Publication No. 10-146390

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

[0006] However, as the distal end of the guidewire is repeatedly shaped to accommodate various blood vessel shapes, the coil body undergoes plastic deformation, which tends to cause the shape to become distorted or for some of the wires that make up the coil body to become misaligned radially.

[0007] When attempting to reshape a guide wire in which such a coil body has been plastically deformed, it may become difficult to reshape it into the desired shape, or some of the wires that make up the coil body may shift radially, resulting in a step on the outer periphery of the guide wire.

[0008] The present invention has been made based on the above circumstances, and its object is to provide a guide wire that can suppress irreversible curling at the tip of the coil body and suppress radial displacement of the wires that make up the coil body.

[0009] Some aspects of the present disclosure include: (1) 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 fixing portion at 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 openly wound portion having gaps between portions of the wire adjacent along the longitudinal axis of the core shaft, and the openly wound portion of the outer coil body 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 representative value of the pitch of the wire in the outer coil body.(2) The medical device according to (1), wherein the representative value Pa of the pitch satisfies 1<Pa≦2; (3) The medical device according to (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 (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 (2) to (4), wherein the representative value Pa of the pitch satisfies 1<Pa≦1.5; (6) The medical device according to (5), wherein the representative value Pa of the pitch satisfies 1<Pa≦1.1; (7) The medical device according to any one of (1) to (6), wherein the tip of the open coiled portion is located at the tip of the outer coil body and the base end of the open coiled portion is located at a position 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 (1) to (7), further comprising an inner coil body that covers at least a part of the tip end of the core shaft, is disposed inside the outer coil body, and is formed by winding a wire at a constant pitch; (9) The medical device according to (8), in which 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 is different from the inclination angle of the wire in the inner coil body with respect to the long axis of the core shaft; (10) The medical device according to any one of (1) to (9), in which the bending angle of the tip end of the outer coil body with respect to the long axis tip direction is 180 degrees or less, measured by twisting the base end of the core shaft three times in the circumferential direction while fixing the tip fixing part, then releasing the fixation of the tip fixing part and removing the outer coil body; (11) The medical device according to (10), in which the bending angle is 90 degrees or less; (12) The medical device according to (11), wherein the bending angle is 45 degrees or less.

[0010] In this specification, the term "effective diameter" refers to the value calculated by subtracting the radius of the coil wires from the outer diameter of the coil body by two. The term "distal side" refers to the direction along the longitudinal axis of the medical device (guidewire) and the direction toward deeper (distal) insertion into a body cavity. The term "proximal side" refers to the direction along the longitudinal axis of the medical device and the opposite direction to the "distal side." The term "distal" refers to the distal end of any component or part, and the term "proximal end" refers to the proximal end of any component or part. The term "distal portion" refers to the portion of any component or part that includes the distal end and extends from the distal end to the midpoint of the longitudinal axis. The term "proximal end" refers to the portion of any component or part that includes the proximal end and extends from the proximal end to the midpoint of the longitudinal axis. The term "radial direction" refers to the radial direction perpendicular to the longitudinal axis of the core shaft. The term "representative pitch" refers to the degree of pitch of the wires constituting the outer coil body in the longitudinal axis direction of the core shaft.

[0011] The present invention can provide a guide wire that can suppress irreversible curling at the distal end and can also suppress radial displacement of the wires that make up the coil body.

[0012] Fig. 1 is a schematic cross-sectional view showing a first embodiment; Fig. 2 is a schematic cross-sectional view showing an enlarged view of a part of Fig. 1; Fig. 3 is a schematic cross-sectional view showing an enlarged view of a part of a second embodiment; Fig. 4 is an explanatory view showing a test method for a habit-forming test; Fig. 5 is an external photograph showing an example of a habit-forming test; Fig. 6 is an explanatory view showing a measurement method for a habit-forming test;

[0013] The medical device of the present disclosure is a medical device comprising a core shaft, an outer coil body formed by winding wire so as 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 parts 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, 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. Furthermore, the dimensions of each part shown in the drawings are shown to facilitate understanding of the implementation details and do not necessarily correspond to actual dimensions. In the first and second embodiments shown below, a guidewire will be described as an example of a medical device.

[0015] 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 fixing portion 41, and a proximal fixing portion 51.

[0016] The core shaft 11 is a longitudinal member that constitutes the central axis of the guide wire 1. Specifically, the core shaft 11 can be formed, for example, so that the diameter of its distal end portion gradually decreases toward the distal end.

[0017] The core shaft 11 of this embodiment is configured, in this order from the tip, with 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. The first columnar section 111 is a section having a uniform cross section (e.g., a flattened 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 extending from the base end of the first tapered section 112 toward the base end side and having a uniform cross section (e.g., a flattened shape). The second tapered section 114 is a tapered section 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 uniform cross section (for example, a cylindrical shape) that extends from the base end toward the base end 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 identical and continuous.

[0018] As the material for constructing the core shaft 11, for example, stainless steel such as SUS304, superelastic alloys such as Ni-Ti alloys, etc. can be used in order to increase the flexibility of the guide wire 1 and to impart antithrombogenicity and biocompatibility.

[0019] The outer coil body 21 is a spiral member formed by winding a wire w1 and is provided so as to cover at least a portion of the tip of the core shaft 11. The wire w1 may be one or more solid wires, one or more twisted wires, or a combination thereof. Note that a solid wire refers to one single wire, and a twisted wire refers to 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 formulas (1) and (2): 3.5≦D / d≦6.5 (1) 1<Pa≦3 (2) where, 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 formula (2), Pa represents a representative value of the pitch of the wires w1 in the outer coil body 21.

[0021] Specific examples of the representative pitch value Pa include the arithmetic mean value (Pmin+Pmax) / 2d of the pitches of the outer coil body 21 in the sparsely wound portion 21A, and the mean value ΣP / n calculated from each pitch P. Here, Pmin represents the smallest pitch among the pitches P of the outer coil body 21, Pmax represents the largest 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 sparsely wound portion 21A.

[0022] Here, the representative pitch value Pa preferably satisfies 1 < Pa ≦ 2, more preferably 1 < Pa ≦ 1.5, and even more preferably 1 < Pa ≦ 1.1. Furthermore, the lower limit of the representative pitch value Pa is preferably 1.01 (1.01 ≦ Pa), regardless of the upper limit. When the representative pitch value Pa satisfies the above relationship, irreversible curling at the tip end of the outer coil body 21 and radial displacement of the wires 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. Furthermore, 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. When D / d satisfies at least one of the above relationships, irreversible curling at the tip end of the outer coil body 21 is suppressed while also suppressing the occurrence of positional misalignment.

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

[0025] The outer coil body 21 may be made of, for example, stainless steel such as SUS316; superelastic alloys such as Ni-Ti alloys; or 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 hemispherical shape so as not to damage the inner wall of the blood vessel when the guide wire 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 the portion that was originally the tip of the core shaft 11 and the portion that was originally the tip of the outer coil body 21. Examples of brazing materials 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 portion 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 the present 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 to the base end portion of the outer coil body 21 via a brazing material or by bonding them using an adhesive. Examples of the brazing material include the brazing material used to form the tip fixing portion 41. Examples of the adhesive include an epoxy adhesive, a cyanoacrylate adhesive, an acrylic adhesive, etc.

[0030] Next, we will explain how to use the guidewire 1. First, before inserting the guidewire 1 into a blood vessel, the distal end of the guidewire 1 is bent (shaped) into a desired shape (e.g., a J-shape). Next, the guidewire 1 is inserted into the blood vessel from its distal end, and the proximal end of the guidewire 1 exposed outside the body is manipulated to advance the distal end to the site to be treated within the blood vessel.

[0031] Next, after the distal end of the guidewire 1 has reached the site to be treated, the proximal end of the guidewire 1 is inserted into the lumen of a medical device (not shown) such as a catheter from its distal end, and the medical device is advanced into the blood vessel along the guidewire 1. Next, after the medical device has reached the site to be treated, various treatments are performed using the medical device. Next, after the treatment is completed, the medical device 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-described guidewire 1, the distal end of the removed guidewire 1 tends to deform into a shape different from the shape it was originally formed into. Therefore, when another medical device is subsequently used or when the same medical device is to be inserted into a blood vessel again, the distal end of the removed guidewire 1 may be reshaped into a desired shape (which may be a new shape different from the shape it was originally formed into) and used (reshaped). The reshaped guidewire 1 can be reused, for example, in the same manner as in the use procedure for the above-described guidewire 1.

[0033] As described above, the guidewire 1 (medical device) has the above-described configuration, which prevents irreversible curling at the distal end of the outer coil body 21 and prevents radial displacement of the wires w1 that make up the outer coil body 21. As a result, even if the distal end of the guidewire 1 is repeatedly shaped, the outer coil body 21 is less likely to curl, and when re-shaped, it can be easily and reliably shaped into a desired shape. Furthermore, because steps are less likely to occur in the outer coil body 21, the guidewire 1 and medical devices such as catheters used in combination with the guidewire 1 can be more smoothly delivered to the treatment site.

[0034] The reasons for the suppression of the irreversible curling and the suppression of the positional displacement of the wires are presumed to be as follows.

[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 bent 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, making it less likely for the wires in the outer coil body to become plastically distorted when 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, making it less likely for the wires in the outer coil body 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 formulas (1) and (2), it is possible to suppress irreversible deformation at the tip of the outer coil body 21 while also 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 a 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 fixation portion 41, and proximal fixation 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 configuration other than the configuration of the inner coil body 32 described below is the same as that of the first embodiment, and therefore the same parts are designated by the same reference numerals and detailed description thereof will be omitted. The manner of use 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. The wire w2 may be, for example, one or more solid wires, one or more twisted wires, or a combination thereof.

[0040] The inner coil body 32 may be made of, for example, stainless steel such as SUS316; superelastic alloys such as Ni-Ti alloys; or radiopaque metals such as platinum and tungsten.

[0041] The inner coil body 32 can have, for example, a distal end that is integrally fixed to the core shaft 11 and the outer coil body 21 at a distal end fixing portion 41, and a proximal end that is fixed to any one of the outer peripheral surfaces s of the core shaft 11. In the inner coil body 32 of this embodiment, the distal end is fixed at the distal end fixing portion 41, and the proximal end is fixed to the outer peripheral 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 distal end fixing portion 41 and the proximal end fixing portion 52, for example, the same methods as those used for fixing the distal end fixing portion 41 and the proximal end fixing portion 51 of the outer coil body 21 described above, respectively, can be used.

[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 may be different from 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 (see Figure 3).

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

[0044] As described above, the guidewire 2 (medical device) includes the inner coil body 32, and therefore, the wires w1 that make up the outer coil body 21 can be prevented from shifting in position in the radial direction.

[0045] The present disclosure is not limited to the configurations of the above-described embodiments, but is intended to include all modifications within the meaning and scope of the claims as defined by the claims. Part of the configurations of the above-described embodiments may be deleted or replaced with other configurations, or other configurations 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 loosely wound portion 21A and the tightly wound portion 21B. However, the outer coil body 21 may be configured only with the loosely wound portion 21A without the tightly wound portion 21B.

[0047] In the above-described embodiment, the guidewires 1 and 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 along the longitudinal axis of the outer coil body or at the proximal end.

[0048] Furthermore, in the above-described embodiment, the guidewires 1 and 2 (medical devices) have been described in which the openly coiled portion 21A is provided at only one location on the outer coil body 21. However, the openly 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 this order from the distal end: 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. 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 calculated 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 of the open coil portion to the base end.

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

[0052] <Evaluation> Each guidewire shown in Table 1 was evaluated for its ability to prevent deformation and displacement according to the following methods. The results are also shown in Table 1.

[0053] [Bending prevention] While the distal fixing portion of the guide wire used in the test (bending test) was fixed, the base end of the core shaft was twisted three times in the circumferential direction, and then the fixation of the distal fixing portion was released, and the outer coil body was removed and measured. At this time, the degree of bending (bending angle) of the distal end of the outer coil body relative to the longitudinal direction of the distal end was measured, and this measurement value was used as an index to evaluate the bending prevention ability.

[0054] Specifically, as shown in FIG. 4A(a), a guidewire to be tested was inserted into 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 via a hole 91b. Next, as shown in FIG. 4A(b), the guidewire was twisted three times in the circumferential direction relative to the silicone tube 91. FIG. 4B is a 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 removed from the silicone tube 91. Next, the guidewire was disassembled, the outer coil body was removed, and the angle (bending angle θ3) at which the tip of the outer coil body (21) bent relative 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 was 180 degrees or less, the ability to suppress the formation of curl was evaluated as good, and when the bending angle θ3 was greater than 180 degrees, the ability to suppress the formation of curl was evaluated as poor. In addition, when the bending angle θ3 was 90 degrees or less, the ability to suppress the formation of curl was evaluated as even better, and when the bending angle θ3 was 45 degrees or less, the ability to suppress the formation of curl was evaluated as best.

[0056] [Displacement suppression ability] Using the outer coil body after the evaluation of the ability to suppress the formation of curl as described above, a stereoscopic image was observed under a microscope at a magnification of 20. During this observation, the number of misaligned locations (locations that were clearly recognized as being misaligned) per outer coil body was counted, and the number was used as an index to evaluate the ability to suppress the displacement.

[0057]

[0058] As can be seen from the results in Table 1, for Nos. 1 to 29, the representative pitch value Pa was greater than 1, and therefore the positional displacement suppression was good. The ratio of the effective diameter D of the outer coil body 21 to the wire diameter d of the outer coil body 21 is preferably 4.5 or greater and 5.5 or less. The ratio of the effective diameter D of the outer coil body 21 to the wire diameter d of the outer coil body 21 is preferably 4.5 or greater and 5 or less. This is because a smaller effective diameter D makes it easier to apply to guidewires with small maximum outer diameters. Furthermore, the ratio of the effective diameter D of the outer coil body 21 to the wire diameter d of the outer coil body 21 is also preferably 5 or greater and 5.5 or less. This is because the bending angle is suppressed.

[0059] REFERENCE SIGNS LIST 1, 2 Medical device (guide wire) 11 Core shaft 21 Outer coil body 21A Openly wound portion 32 Inner coil body 41 Tip fixing portion D Effective diameter of outer coil body d Wire diameter of outer coil body Pa Representative value of pitch θ1, θ2 Inclination angle θ3 Bending angle z2 Long axis of outer coil body

Claims

1. A medical device comprising: a core shaft; an outer coil body formed by winding a wire and provided so as to cover at least a portion of the tip of the core shaft; and 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, wherein the outer coil body has an open winding portion having a gap between adjacent wire portions along the longitudinal axis of the core shaft, and the open winding portion of the outer coil body 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 representative value of the pitch of the wire in the outer coil body.) 2. The medical device of claim 1, wherein the representative value Pa of the pitch satisfies 1<Pa≦2.

3. A medical device as described in 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. A medical device as described in 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. A 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. A medical device according to any one of claims 1 to 6, wherein the tip of the open winding portion is located at the tip of the outer coil body, and the base end of the open winding portion is located at a position 10 mm to 30 mm from the tip of the outer coil body toward the base end.

8. A medical device described in any one of claims 1 to 7, further comprising an inner coil body covering at least a portion of the tip of the core shaft, positioned inside the outer coil body, and formed by winding a wire at a constant pitch.

9. A medical device as described in claim 8, wherein the winding direction of the wire in the outer coil body is opposite to the winding direction of the wire in the inner coil body, and the inclination angle of the wire in the outer coil body relative to the long axis of the core shaft is different from the inclination angle of the wire in the inner coil body relative to the long axis of the core shaft.

10. A medical device as described in any one of claims 1 to 9, in which the base end of the core shaft is twisted circumferentially three times while the tip fixation portion is fixed, and then the fixation of the tip fixation portion is released, the outer coil body is removed, and the bending angle of the tip of the outer coil body relative to the long axis tip direction is measured, and is 180 degrees or less.

11. The medical device of claim 10, wherein the bend angle is 90 degrees or less.

12. The medical device of claim 11, wherein the bend angle is 45 degrees or less.

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