Multilayer coil body

Abstract

To provide a multilayer coil body capable of achieving both enough torque transmission property and high flexibility.SOLUTION: A multilayer coil body 1 includes: a hollow first coil layer 11 where a first coil 11w is spirally wound around; a third coil layer 31 provided so as to cover the first coil layer 11 and where the third coil 31w is spirally wound around; and a second coil layer 21 provided adjacent between the first coil layer 11 and the third coil layer 31 and where a second coil 21w is spirally wound around. A cross sectional area of at least one coil 21w composing the second coil layer 21 is larger than a cross sectional area of at least one coil 31w composing the first coil layer 11 and the third coil layer 31, and a gap 21g is formed between at least a part of the adjacent second coils 21w in a long axis direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a multi-layer coil body. [Background technology]

[0002] Long medical instruments such as catheters are known as instruments that are inserted into body cavities such as blood vessels to treat lesions, etc. When rotating the distal end of such a medical instrument inserted into a body cavity, excellent torque transmission is required to reliably transmit the rotational force from the handle to the distal end.

[0003] As an example of the medical device described above, one that includes a coil body having multiple coil layers arranged adjacent to each other in a direction (radial direction) perpendicular to the longitudinal axis direction of the medical device has been disclosed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-107326 Summary of the Invention [Problem to be solved by the invention]

[0005] However, while the coil bodies used in the above-mentioned conventional medical devices can ensure sufficient torque transmission, they are not necessarily sufficient in terms of ensuring high flexibility to follow the complex curved shapes of body cavities.

[0006] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a multi-layer coil body that can achieve both sufficient torque transmission performance and high flexibility. [Means for solving the problem]

[0007] Some aspects of the present disclosure include: (1) a hollow first coil layer in which a first winding is wound spirally; a third coil layer provided to cover the first coil layer and having a third winding wound in a spiral shape; a second coil layer provided between the first coil layer and the third coil layer so as to be adjacent thereto, and having a second winding wound in a spiral shape; a cross-sectional area of ​​at least one winding constituting the second coil layer is larger than a cross-sectional area of ​​at least one winding constituting the first coil layer and the third coil layer; a multilayer coil body, characterized in that a gap is formed between at least some of the second windings adjacent to each other in the longitudinal direction; (2) The multilayer coil body according to (1), wherein the outermost periphery of the second winding has a substantially rectangular cross-section. (3) The multilayer coil body according to (1) or (2), wherein the gaps formed between the second windings include two or more gaps having different lengths in the longitudinal direction. (4) The multilayer coil body according to (3), wherein the second winding includes a radiopaque material; and (5) The multilayer coil body according to any one of (1) to (4), wherein a conductor is provided in the gap formed between the second windings.

[0008] In this specification, the term "winding" refers to a linear member that is wound spirally to form a coil layer. The member may be a solid wire (single wire) or a twisted wire. The "transverse area of ​​a winding" refers to the cross-sectional area of ​​a cross section perpendicular to the spiral direction of the winding. In other words, it can also be referred to as the cross-sectional area of ​​a cross section perpendicular to the direction of progression (spiral direction) of a winding that advances spirally. [Effects of the Invention]

[0009] The present invention can provide a multilayer coil body that can achieve both sufficient torque transmission performance and high flexibility. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic longitudinal sectional view showing the entire first embodiment. [Figure 2] FIG. 1 is a schematic longitudinal sectional view showing a part of a first embodiment. [Figure 3] FIG. 10 is a schematic vertical cross-sectional view showing a part of a modified example. [Figure 4] FIG. 10 is a schematic longitudinal sectional view showing a part of the second embodiment. [Figure 5] FIG. 10 is a schematic longitudinal sectional view showing a part of a third embodiment. [Figure 6] FIG. 10 is a schematic longitudinal sectional view showing the entire fourth embodiment. [Figure 7] FIG. 10 is a schematic longitudinal sectional view showing the whole of a fifth embodiment. [Figure 8] FIG. 10 is a schematic longitudinal sectional view showing the entire sixth embodiment. [Figure 9] FIG. 10 is a schematic vertical cross-sectional view showing a part of the sixth embodiment. [Figure 10] FIG. 10 is a schematic vertical cross-sectional view showing a part of a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] The multilayer coil body of the present disclosure is a multilayer coil body comprising: a hollow first coil layer in which a first winding is spirally wound; a third coil layer that is arranged to cover the first coil layer and in which a third winding is spirally wound; and a second coil layer that is arranged adjacent to the first coil layer and the third coil layer and in which a second winding is spirally wound, wherein the cross-sectional area of ​​at least one winding that constitutes the second coil layer is larger than the cross-sectional areas of at least one winding that constitutes the first coil layer and the third coil layer, and a gap is formed between at least some of the adjacent second windings in the longitudinal axis direction.

[0012] In this specification, the term "distal side" refers to the direction along the longitudinal axis of the multilayer coil body, that is, the direction advancing toward the treatment site. The term "base end side" refers to the direction along the longitudinal axis, that is, the direction opposite to the distal side. Furthermore, the term "distal end" refers to the distal end of any member or site, and the term "base end" refers to the proximal end of any member or site. Unless otherwise specified, the terms "longitudinal direction" and "radial direction" refer to the longitudinal axis direction and radial direction (direction perpendicular to the longitudinal axis direction) of the multilayer coil body, respectively.

[0013] Hereinafter, first to sixth 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 shown in each drawing are intended to facilitate understanding of the implementation details and do not necessarily correspond to actual dimensions. In each drawing, the left side of the drawing indicates the distal end side of the multilayer coil body, and the right side indicates the proximal end side of the multilayer coil body.

[0014] [First embodiment] 1 and 2 are schematic diagrams showing a first embodiment. As shown in FIGS. 1 and 2, a multilayer coil body 1 is generally composed of a first coil layer 11, a second coil layer 21, and a third coil layer 31.

[0015] The first coil layer 11 is a hollow layer around which the first winding wire 11w is wound in a spiral shape. Specifically, the first coil layer 11 can be formed by using a single wire (single wire) or a twisted wire having a circular cross section, for example, as the first winding wire 11w, and winding this member in a single or multiple strands. Adjacent first winding wires 11w in the longitudinal direction may be in contact with each other or may be spaced apart. When the first winding wires 11w are spaced apart from each other, the gap between the first winding wires 11w may be configured to be smaller than the gap between the second winding wires 21w (described later) (not shown). In this embodiment, a single wire 111w having a circular cross section is used as the first winding wire 11w, and this first winding wire 11w is wound in a single strand and arranged so that adjacent first winding wires 11w are in contact with each other. In addition, an inner cavity 1h is formed inside the first coil layer 11. For example, a guide wire (not shown) can be inserted into the lumen 1h.

[0016] The second coil layer 21 is provided adjacent to the first coil layer 11 and the third coil layer 31 described later, and is a layer in which the second winding 21w is wound in a spiral shape. Specifically, the second coil layer 21 can be formed by using a solid wire (single wire) or a twisted wire as the second winding 21w and winding this member in a single-strand or multiple-strand configuration.

[0017] The contour shape of the outermost periphery of the second winding 21w in cross section may be circular or substantially rectangular. If the contour shape is rectangular, the cross-sectional area of ​​the second winding 21w can be increased while saving space, and a second winding having a rectangular cross section can effectively improve torque transmissibility. In this embodiment, a single wire 211w whose outermost periphery in cross section has a rectangular contour shape is used as the second winding 21w, and the second coil layer 21 is exemplified by winding this second winding 21w as a single strand.

[0018] When the cross-sectional contour of the second winding 21w is rectangular, the aspect ratio of the cross-section (the ratio of the width to the height of the rectangle) may be set, for example, as a ratio of length to width = 1:10 (flat shape) to 1:1 (square shape). In the case of a flat shape, it is preferable to arrange the flat surfaces so that they are in contact with the first and third coil layers 11, 31. This prevents the multilayer coil body 1 from collapsing due to pressure from the outside in the radial direction, and further improves torque transmissibility and flexibility, particularly torque transmissibility. Furthermore, a square shape can further improve torque transmissibility and flexibility, particularly flexibility.

[0019] The third coil layer 31 is provided to cover the first coil layer 11 and is a layer in which a third winding 31w is wound in a spiral shape. Specifically, the third coil layer 31 can be formed, for example, by using a solid wire (single wire) or a twisted wire having a circular cross section as the third winding 31w and winding this member in a single or multiple strands. Adjacent third windings 31w in the longitudinal direction may be in contact with each other or may be spaced apart. When the third windings are spaced apart, as shown in FIG. 3, the gap A31g between the third windings A31w may be configured to be smaller than the gap 21g between the second windings 21w, for example. In this embodiment, a single wire 311w having a circular cross section is used as the third winding 31w, and the third coil layer 31 is exemplified in which the third winding 31w is wound as a single strand and adjacent third windings 31w are in contact with each other (see Figure 2).

[0020] Here, gaps 21g are formed between at least some of the adjacent second windings 21w in the longitudinal direction. These gaps 21g may be formed between each of the adjacent second windings, or may be formed only between specific second windings, with the second windings other than the specific second windings being in contact with each other.

[0021] The length L of the gap 21g in the longitudinal direction can be determined appropriately depending on the flexibility required for each portion of the multilayer coil body 1 in the longitudinal direction, etc. The length L of the gap 21g can be set to, for example, 0.001 mm to 1 mm. When the length L of the gap 21g is large, the flexibility of the multilayer coil body in that portion can be increased, and when the length L of the gap 21g is small, the rigidity of the multilayer coil body in that portion can be increased. In this embodiment, the multilayer coil body 1 is exemplified in which the second windings 21w of the gaps 21g having the same length L are adjacent to each other.

[0022] Furthermore, in the multilayer coil body 1, the cross-sectional area of ​​at least one winding 21w constituting the second coil layer 21 is configured to be larger than the cross-sectional area of ​​at least one winding 11w, 31w constituting the first coil layer 11 and the third coil layer 31. More specifically, the cross-sectional area of ​​at least one winding 21w constituting the second coil layer 21 is configured to be larger than the cross-sectional area of ​​the winding having the largest cross-sectional area among the windings 11w, 31w constituting the first coil layer 11 and the third coil layer 31.

[0023] In the multilayer coil body 1 of this embodiment, the first winding wire 11w and the third winding wire 31w are each configured as a single wire and a single filament, and the second winding wire 21w is also configured as a single wire and a single filament. Therefore, the cross-sectional area of ​​the single wire 211w (element wire) that constitutes the second winding wire 21w is configured to be larger than both the cross-sectional area of ​​the single wire 111w (element wire) that constitutes the first winding wire 11w and the cross-sectional area of ​​the single wire 311w (element wire) that constitutes the third winding wire 31w.

[0024] The winding directions of adjacent windings in the radial direction may be opposite to each other (for example, the first winding is S-twisted, the second winding is Z-twisted, and the third winding is S-twisted). In this manner, when the windings are opposite to each other, the force in the longitudinal direction applied to adjacent windings in the radial direction can be made to face each other when the multilayer coil body is rotated around the longitudinal axis, and therefore, regardless of the direction in which the multilayer coil body is rotated, a decrease in torque transmissibility due to the separation between adjacent windings in the longitudinal direction can be suppressed.

[0025] The wire material constituting the first winding 11w, the second winding 21w, and the third winding 31w can be, for example, stainless steel such as SUS316, a superelastic alloy such as a Ni-Ti alloy, or a radiopaque metal such as platinum or tungsten, from the viewpoint of providing antithrombogenicity and biocompatibility. The wire material of each winding may be the same material, or may contain different materials.

[0026] As described above, the multilayer coil body 1 has the above-described configuration, which allows for both sufficient torque transmission and high flexibility. Furthermore, by appropriately adjusting the length L (spacing) of the gap 21g, the multilayer coil body 1 can be made hard or soft, allowing for an appropriate adjustment of the balance between flexibility and rigidity.

[0027] [Second embodiment] Fig. 4 is a schematic diagram showing the second embodiment. As shown in Fig. 4, the multilayer coil body 2 is generally composed of a first coil layer 11, a second coil layer 22, and a third coil layer 31. The multilayer coil body 2 differs from the first embodiment in that it includes the second coil layer 22. Note that the first coil layer 11 and the third coil layer 31 are the same as those in the first embodiment, and therefore the same parts are denoted by the same reference numerals and detailed description thereof will be omitted. Furthermore, the configurations other than the configuration of the second coil layer 22 described below are the same as those in the first embodiment.

[0028] The second coil layer 22 is provided adjacently between the first coil layer 11 and the third coil layer 31, and is a layer in which the second winding 22w is wound in a spiral shape. In this embodiment, the second winding 22w is made of three single wires 221w, 222w, and 223w whose outermost periphery has a rectangular outline shape in cross section and whose cross-sectional areas are equal to each other, and the second coil layer 22 is wound in a triple (multiple) formation.

[0029] In the multilayer coil body 2, a gap is formed between adjacent second windings 22w in the longitudinal direction of the second coil layer 22. Specifically, in the multilayer coil body 2, three single wires 221w, 222w, and 223w constituting the second winding 22w are in contact with each other in the longitudinal direction to form a set, and a gap 22g is formed between adjacent sets of windings (three second windings 22w) in the longitudinal direction.

[0030] In the multilayer coil body 2 of this embodiment, the first winding 11w and the third winding 31w are each configured as a single-wire, single-strand winding, and the second winding 22w is configured as a single-wire, triple-strand (multi-strand) winding. Specifically, the cross-sectional area of ​​at least one winding 21w constituting the second coil layer 21 is configured to be larger than the cross-sectional area of ​​at least one winding 11w, 31w constituting the first coil layer 11 and the third coil layer 31. More specifically, the cross-sectional area of ​​at least one winding 21w constituting the second coil layer 21 is configured to be larger than the cross-sectional area of ​​the winding having the largest cross-sectional area out of the windings 11w, 31w constituting the first coil layer 11 and the third coil layer 31.

[0031] As described above, the multilayer coil body 2 has the above-described configuration, which allows for both sufficient torque transmission and high flexibility. Furthermore, by appropriately adjusting the length L (spacing) of the gap 22g, the multilayer coil body 2 can be made hard or soft, allowing for an appropriate adjustment of the balance between flexibility and rigidity.

[0032] [Third embodiment] Fig. 5 is a schematic longitudinal sectional view showing the third embodiment. As shown in Fig. 5, the multilayer coil body 3 is generally composed of a first coil layer 11, a second coil layer 23, and a third coil layer 31. The multilayer coil body 3 differs from the first embodiment in that it includes the second coil layer 23. Note that the first coil layer 11 and the third coil layer 31 are the same as those in the first embodiment, and therefore the same parts are denoted by the same reference numerals and detailed description thereof will be omitted. Furthermore, the configurations other than the configuration of the second coil layer 23 shown below are the same as those in the first embodiment.

[0033] The second coil layer 23 is provided adjacently between the first coil layer 11 and the third coil layer 31, and is a layer in which the second winding 23w is wound in a spiral shape. In this embodiment, the second winding 23w is a single wire 231w whose outermost periphery has a rectangular outline shape in cross section, and the second coil layer 23 is wound in a single strand (single wire).

[0034] In the multilayer coil body 3, gaps 23g are formed between adjacent second windings 23w in the long axis direction of the second coil layer 23. The gaps 23g formed between the second windings 23w in the multilayer coil body 3 include two or more gaps 23g having different lengths in the long axis direction (for example, gaps 231g, 232g).

[0035] Examples of the gaps 23g having different lengths include gaps 23g in which the length L of the gaps 23g increases monotonically and / or stepwise along the longitudinal direction, gaps 23g in which the length L varies only at a predetermined portion in the longitudinal direction (the length L of the gaps 23g is large or small only at a predetermined portion), etc. In this embodiment, the second coil layer 23 in which the length L of the gaps 23g increases monotonically toward the tip side is exemplified.

[0036] The second winding 23w may contain a radiopaque material (such as an X-ray opaque material) in the multilayer coil body 3. When the wire material constituting the second winding 23w contains a radiopaque material, the position of the gap in the longitudinal direction can be identified in a radiographic image based on the relationship between the length L of the contrasted gap and the lengths of other gaps, allowing for more accurate manipulation of the multilayer coil body within a body cavity.

[0037] Examples of the radiopaque material include gold, platinum, tungsten, and alloys containing these elements (e.g., platinum-nickel alloys, etc.). The radiopaque material may be a combination of a radiopaque material and a radiotransparent material, such as a material coated on the surface of a non-radiopaque material (radiotransparent material).

[0038] As described above, the multilayer coil body 3 includes two or more gaps 23g with different lengths L in the long axis direction, which allows for varying degrees of flexibility in the long axis direction of the multilayer coil body 3. Furthermore, by appropriately adjusting the length L (spacing) of the gaps 23g, the multilayer coil body 3 can be made hard or soft, allowing for appropriate adjustment of the balance between flexibility and rigidity.

[0039] [Fourth embodiment] Fig. 6 is a schematic longitudinal sectional view showing a fourth embodiment. In this embodiment, a catheter using the multilayer coil body of the present disclosure is illustrated. As shown in Fig. 6, the catheter C is generally composed of a multilayer coil body 4, a distal tip 44, and a base portion 54.

[0040] The multilayer coil body 4 includes a first coil layer 11, a second coil layer 24, and a third coil layer 31. The first coil layer 11 and the third coil layer 31 are the same as those in the first embodiment, so the same parts are denoted by the same reference numerals and detailed description thereof will be omitted. In addition, the configurations other than the configuration of the second coil layer 24 described below are the same as those in the first embodiment.

[0041] The second coil layer 24 of the catheter C is configured so that the length L of the gaps 241g between the second windings 24w at the distal end of the multilayer coil body 4 is greater than the length L of the gaps 242g at the proximal end. This makes it possible to make the distal end of the multilayer coil body 4 more flexible than the proximal end, allowing the catheter C to be advanced more smoothly while the distal end conforms to the curved body cavity.

[0042] The distal tip 44 is a member joined to one end of the multilayer coil body 4. Specifically, the distal tip 44 is formed so that the distal portion is rounded toward the distal end so that the multilayer coil body 4 can easily move within a body cavity such as a blood vessel. The distal tip 44 has an inner cavity 44h with an opening 44a at its distal end.

[0043] As a method for joining the distal tip 44 and the multilayer coil body 4, for example, a method can be adopted in which the distal ends of the first winding 11w, the second winding 24w, and the third winding 31w that constitute the multilayer coil body 4 are embedded in the base end of the distal tip 44 by welding or the like.

[0044] The material constituting the distal tip 44 is preferably antithrombotic, biocompatible, and flexible so as to absorb impacts on the body cavity, etc. Examples of such materials include resin materials such as polyurethane and polyurethane elastomer.

[0045] The base 54 is a member with which the operator grips the catheter C. The base 54 is connected, for example, to the proximal end of the multilayer coil body 4, and has a lumen 54h that communicates with the lumen 4h of the multilayer coil body 4. An opening 54a is formed at the end of the lumen 54h on the proximal side. The shape of the base 54 is not particularly limited as long as it does not impair the effects of the present invention, and can be formed, for example, into a shape that is easy for the operator to manipulate.

[0046] Here, a lumen M is formed by the lumen 44h of the distal tip 44, the lumen 4h of the multilayer coil body 4, and the lumen 54h of the base portion 54. A medical instrument such as a guidewire (not shown) is inserted into this lumen M.

[0047] Next, a description will be given of a mode of use of the catheter C. Here, an example will be given of a procedure in which the catheter C is used as a guiding catheter to dilate a stenotic part occurring in a coronary artery of the heart with a balloon catheter.

[0048] Prior to using catheter C, first, guidewire A (not shown) is inserted into a blood vessel and its tip is advanced until it approaches the entrance to the coronary artery of the heart. Next, guidewire A is inserted into lumen M of catheter C, and catheter C is advanced while being pushed into the blood vessel along guidewire A so that the tip reaches the entrance to the coronary artery of the heart. During this process, catheter C is advanced while following the curvature of the blood vessel.

[0049] Next, guidewire A is removed and replaced with a thinner guidewire B (not shown) for a balloon catheter, and the tip of guidewire B is brought to a position where it passes through the stenotic site via catheter C. Next, a balloon catheter (not shown) is inserted along guidewire B to the inside of the stenotic site, and the balloon dilates the stenotic site, thereby performing treatment. After this treatment, the balloon catheter, guidewire B, and catheter C are removed from the body in this order, completing the procedure.

[0050] As described above, the catheter C has the above-described configuration, and the excellent torque transmission capability and high flexibility of the multilayer coil body 4 allow the rotational force applied to the base portion 54 to be reliably transmitted to the distal end of the catheter C, and the catheter C can exhibit high followability even in complexly curved blood vessels. Furthermore, by appropriately adjusting the length L (spacing) of the gap 24g, the multilayer coil body 4 can be made either rigid or flexible, and the balance between flexibility and penetration force of the catheter C can also be appropriately adjusted.

[0051] [Fifth embodiment] 7 is a schematic longitudinal sectional view showing a fifth embodiment. In this embodiment, a guidewire using the multilayer coil body of the present disclosure is illustrated. As shown in FIG. 7, the guidewire G1 is generally composed of a core shaft 65, a multilayer coil body 5, a distal fixing portion 75, and a proximal fixing portion 85.

[0052] The core shaft 65 is a longitudinal shaft and may be configured to have, for example, an enlarged diameter portion 652, a small diameter portion 651, and a large diameter portion 653.

[0053] The expanded diameter portion 652 is a portion whose diameter expands toward the base end side. The small diameter portion 651 is a portion whose base end is located at the tip of the expanded diameter portion 652 and extends toward the tip end side. The large diameter portion 653 is a portion whose tip is located at the base end of the expanded diameter portion 652 and extends toward the base end side. Note that each of the small diameter portion 651 and the large diameter portion 653 can be configured to have a constant outer diameter along the longitudinal direction of the core shaft 65.

[0054] As a material for forming the core shaft 65, for example, stainless steel such as SUS304, superelastic alloy such as Ni-Ti alloy, etc. can be used in order to improve the flexibility of the guide wire G1 and to impart antithrombogenicity and biocompatibility.

[0055] The multilayer coil body 5 includes a first coil layer 11, a second coil layer 25, and a third coil layer 31. The first coil layer 11 and the third coil layer 31 are the same as those in the first embodiment, so the same parts are denoted by the same reference numerals and detailed description thereof will be omitted. In addition, the configurations other than the configuration of the second coil layer 25 described below are the same as those in the first embodiment.

[0056] The second coil layer 25 of the guidewire G1 is configured so that the length L of the gap 251g at the distal end of the multilayer coil body 5 is greater than the length L of the gap 252g at the proximal end. This makes it possible to make the distal end of the multilayer coil body 5 more flexible than the proximal end, allowing the guidewire G1 to move more smoothly while following the curved body cavity.

[0057] The tip fixing portion 75 is a portion that fixes the tip portion of the multilayer coil body 5 to the tip portion of the core shaft 65. Specifically, the tip fixing portion 75 can be formed, for example, so that the tip portion has a generally hemispherical shape that is convexly curved toward the tip side. This reduces resistance when the guidewire G1 advances inside a blood vessel, allowing the guidewire G1 to be inserted smoothly.

[0058] The tip fixing portion 75 can be formed, for example, by melting the tip portions of the first winding 11w, the second winding 25w, and the third winding 31w that constitute the core shaft 65 and / or the multilayer coil body 5, or by using a brazing material to join the core shaft 65 and the multilayer coil body 5. Examples of the brazing material include metal brazing materials such as Sn—Pb alloy, Pb—Ag alloy, Sn—Ag alloy, and Au—Sn alloy.

[0059] The base end fixing portion 85 is a portion that fixes the base end of the multilayer coil body 5 to the core shaft 65. Specifically, the base end fixing portion 85 can be formed on the expanded diameter portion 652 of the core shaft 5, for example.

[0060] The base end fixing portion 85 can be formed, for example, by melting the base ends of the first winding 11w, the second winding 25w, and the third winding 31w that make up the multilayer coil body 5, or by using a brazing material to join the core shaft 65 and the multilayer coil body 5. Note that the brazing material may be the same as the brazing material used to form the tip fixing portion 75, for example.

[0061] The guidewire G1 can be used in the same manner as the guidewire A and guidewire B described in the usage of the catheter C of the fourth embodiment, for example.

[0062] As described above, the guidewire G1 has the above-described configuration, and the excellent torque transmission capability and high flexibility of the multilayer coil body 5 allow the rotational force applied to the proximal end of the core shaft 65 to be reliably transmitted to the distal end of the guidewire G1, and the guidewire G1 can exhibit high tracking ability even in complexly curved blood vessels. Furthermore, by appropriately adjusting the length L (spacing) of the gap 25g, the multilayer coil body 5 can be made either rigid or flexible, and the balance between flexibility and penetration force of the guidewire G1 can also be appropriately adjusted.

[0063] [Sixth embodiment] 8 and 9 are schematic longitudinal cross-sectional views showing a sixth embodiment. In this embodiment, a guidewire in which a conductor (lead wire) is arranged using the multilayer coil body of the present disclosure is illustrated. As shown in FIGS. 8 and 9, the guidewire G2 is generally composed of a core shaft 65, a multilayer coil body 6, a distal fixing portion 75, a proximal fixing portion 85, a sensor 961, a lead wire 962, and a covering member 963. The guidewire G2 differs from the fifth embodiment in that it includes the multilayer coil body 6, the sensor 961, the lead wire 962, and the covering member 963. Note that the core shaft 65, the distal fixing portion 75, and the proximal fixing portion 85 are the same as those in the fifth embodiment, and therefore the same parts are designated by the same reference numerals and detailed description thereof will be omitted.

[0064] The multilayer coil body 6 includes a first coil layer 11, a second coil layer 25, and a third coil layer 36. The first coil layer 11 and the second coil layer 25 are the same as those in the fifth embodiment, so the same parts are denoted by the same reference numerals and detailed description thereof will be omitted. Furthermore, the configurations other than the configuration of the third coil layer 36 described below are the same as those in the fifth embodiment.

[0065] In the third coil layer 36 of the guidewire G2, adjacent third windings 36w are spaced apart in the longitudinal direction. The gaps 36g between the third windings 36w can be configured to be smaller than the gaps 25g between the second windings 25w, for example.

[0066] The sensor 961 has a base end connected to the tip of a lead wire 962 (described later) and is disposed along a spiral gap 25g formed between adjacent second windings 25w. The tip of the sensor 961 can be embedded in the tip fixing portion 75, or disposed so as to abut against or be close to the base end of the tip fixing portion 75, for example.

[0067] The sensor 961 may be, for example, a temperature sensor or a pressure sensor.

[0068] The sensor 961 may be suitably shaped as a wire or ribbon so as to fit into the gap 25g formed between adjacent second windings 25w.

[0069] The lead wire 962 is an electrical conductor that electrically connects the sensor 961 to an external measuring device main body (not shown). The distal end portion of the lead wire 962 is provided in a gap 25g formed between the second windings 25w. Specifically, the distal end portion of the lead wire 962 is arranged so as to follow the spiral gap 25g formed between adjacent second windings 25w. The proximal end portion of the lead wire 962 can be, for example, extended linearly along the longitudinal direction on the outer circumferential surface of the core shaft 65.

[0070] Preferably, the outer periphery of the lead wire 962 is located inside (in the direction of the central axis of the guidewire G2) the outer periphery of the second winding 25w in the multilayer coil body 6. This makes it possible to prevent a large external force from being directly applied to the lead wire 962, and to prevent the lead wire 962 from being deformed or damaged.

[0071] The material for the lead wire 962 is preferably a metal different from the materials for the first, second, and third windings 11w, 25w, and 36w, and more preferably a metal with lower resistance than the materials for the first, second, and third windings 11w, 25w, and 36w. Examples of such materials include gold, silver, copper, and alloys containing these. These materials have lower rigidity and a narrower elastic range than stainless steel such as SUS316 or superelastic alloys such as Ni-Ti alloys that form the multilayer coil body 6.

[0072] The covering member 963 is a member that electrically insulates the sensor 961 and the lead wire 962 from surrounding members such as the multilayer coil body 6 and body tissues such as blood vessels and blood, and also fixes them to the multilayer coil body 6.

[0073] Examples of materials that can be used to form the covering member 963 include thermosetting electrically insulating resins such as polyimide, thermoplastic electrically insulating resins such as polyamide, etc. Such resins can be formed, for example, by arranging the sensor 961 and the lead wires 962 in the multilayer coil body 6 and the core shaft 65, and then applying a resin composition for forming the resin to the outer peripheries of the sensor 961 and the lead wires 962 by dipping, spraying, or the like, and then subjecting the resin to a heat treatment.

[0074] As described above, the guidewire G2 has the above-described configuration, and therefore the lead wire 962, which has lower rigidity and a smaller elastic range than, for example, stainless steel such as SUS316 or superelastic alloys such as Ni-Ti alloys, can be reinforced with the multilayer coil body 6, thereby preventing breakage of the lead wire 962. Furthermore, by storing the lead wire 962 in the gap 25g of the second winding 25w, space can be used effectively, and the guidewire G2 can be prevented from becoming bulky.

[0075] The present invention is not limited to the configurations of the above-described embodiments, but is intended to include all modifications within the scope and meaning equivalent to the claims. For example, some 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.

[0076] For example, in the above-described embodiment, a multilayer coil body was described in which the second winding is a single wire whose outermost periphery has a rectangular outline in cross section, and the second coil layer is formed by winding this second winding in a single or multiple strands. However, the outline of the second winding 27w of the second coil layer 27 may be a shape other than rectangular, such as a circular single wire 271w (see FIG. 10).

[0077] In the above-described embodiment, a multilayer coil body including a second coil layer using a solid wire as the second winding has been described. However, the second coil layer may be configured with a winding including a twisted wire as the second winding. In such a case, the cross-sectional shape of the wire (single wire) constituting the twisted wire may be rectangular, or may be a shape other than rectangular (e.g., circular), or may be a mixture of these. Furthermore, the second winding constituting the second coil layer may be formed so that the outermost periphery of the wire as a whole in cross section has a substantially rectangular outline shape.

[0078] In the above-described embodiment, a multilayer coil body consisting of three layers (a first coil layer, a second coil layer, and a third coil layer) has been described. However, the multilayer coil body may have a second coil layer between the first coil layer and the third coil layer. For example, the multilayer coil body may have another coil layer inside the first coil layer, or may have another coil layer outside the third coil layer. [Explanation of symbols]

[0079] 1, 2, 3, 4, 5, 6 Multilayer coil body 11 First coil layer 11w 1st winding 21, 22, 23, 24, 25, 27 Second coil layer 21w, 22w, 23w, 24w, 25w, 27w, second winding 21g, 22g, 23g, 24, 25g gap 31, A31, 36 Third coil layer 31w, A31w, 36w third winding C catheter G1, G2 guidewire

Claims

1. a hollow first coil layer in which a first winding is wound spirally; a third coil layer provided to cover the first coil layer and having a third winding wound in a spiral shape; a second coil layer provided between the first coil layer and the third coil layer so as to be adjacent thereto, the second coil layer having a second winding wound in a spiral shape, a cross-sectional area of ​​at least one winding constituting the second coil layer is larger than a cross-sectional area of ​​at least one winding constituting the first coil layer and the third coil layer; a gap is formed between at least some of the second windings adjacent to each other in the longitudinal direction; the second coil layer is adjacent to both the first coil layer and the third coil layer over the entire length in the longitudinal direction; The outermost periphery of the second winding has a substantially rectangular cross section. Multilayer coil body.

2. A hollow first coil layer in which a first winding is wound spirally; a third coil layer provided to cover the first coil layer and having a third winding wound in a spiral shape; a second coil layer provided between the first coil layer and the third coil layer so as to be adjacent thereto, the second coil layer having a second winding wound in a spiral shape, a cross-sectional area of ​​at least one winding constituting the second coil layer is larger than a cross-sectional area of ​​at least one winding constituting the first coil layer and the third coil layer; a gap is formed between at least some of the second windings adjacent to each other in the longitudinal direction; the second coil layer is adjacent to both the first coil layer and the third coil layer over the entire length in the longitudinal direction; The gaps formed between the second windings include two or more gaps having different lengths in the longitudinal direction. Multilayer coil body.

3. 2. The multilayer coil body according to claim 1, wherein the gaps formed between the second windings include two or more gaps having different lengths in the major axis direction.

4. 4. The multilayer coil assembly according to claim 2 or 3, wherein the second winding includes a radiopaque material.

5. A hollow first coil layer in which a first winding is wound spirally; a third coil layer provided to cover the first coil layer and having a third winding wound in a spiral shape; a second coil layer provided between the first coil layer and the third coil layer so as to be adjacent thereto, the second coil layer having a second winding wound in a spiral shape, a cross-sectional area of ​​at least one winding constituting the second coil layer is larger than a cross-sectional area of ​​at least one winding constituting the first coil layer and the third coil layer; a gap is formed between at least some of the second windings adjacent to each other in the longitudinal direction; the second coil layer is adjacent to both the first coil layer and the third coil layer over the entire length in the longitudinal direction; A conductor is provided in the gap formed between the second windings. Multilayer coil body.

6. A multilayer coil body described in any one of claims 1 to 4, wherein a conductor is provided in the gap formed between the second windings.

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