Medical device
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Filing Date
- 2022-11-30
- Publication Date
- 2026-03-26
Abstract
Description
medical devices
[0001] The present invention relates to medical devices such as guidewires and catheters.
[0002] Conventionally, guide wires having multiple coil bodies that cover the outer periphery of a core shaft have been known. Patent Document 1 describes a guide wire that has a first coil that covers the outer periphery of the core shaft and a second coil that covers the outer periphery of the first coil, and the first coil and the second coil are fixed together.
[0003] Special Publication No. 2009-511184
[0004] Conventional guidewires have been configured so that their bending rigidity gradually changes in the axial direction of the guidewire, or the amount of change in bending rigidity in the axial direction of the guidewire is small, which can cause bending of the guidewire to expand (progress) toward the proximal end. This issue is not unique to guidewires, but is also common to medical devices such as catheters.
[0005] An object of the present invention is to prevent bending that occurs in a medical device such as a guidewire from spreading toward the proximal end.
[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following aspects.
[0007] (1) One form of the present invention is a medical device comprising: a core shaft; a first coil body arranged to surround the tip of the core shaft; and a second coil body arranged radially outward of the first coil body, wherein the tip of the second coil body is located between the tip and base end of the first coil body in the axial direction of the core shaft; and a fixing portion that fixes the vicinity of the tip of the second coil body to the first coil body, wherein the axial position of the tip of the fixing portion in a portion of the fixing portion located between the outer and inner circumferences of the second coil body is the same as the axial position of the tip of the second coil body or is closer to the base end than the axial position of the tip of the second coil body.
[0008] According to this configuration, the tip of the fixing portion is positioned at the same position as the tip of the second coil body or closer to the base end than the tip of the second coil body, thereby preventing bending that occurs in the medical device from expanding (progressing) toward the base end.
[0009] (2) In the medical device of the above aspect, the fixing portion may fix the core shaft and the first coil body.
[0010] According to this configuration, the fixing portion fixes the core shaft and the first coil body, thereby improving the torque transmission performance of the medical device.
[0011] (3) In the medical device of the above form, the fixing portion may be a first fixing portion, and the medical device may further include a third coil body arranged radially outward from the second coil body, and a second fixing portion that fixes the second coil body and the third coil body on the base end side of the first fixing portion.
[0012] According to this configuration, the torque transmission performance of the medical device can be improved by the second fixing portion.
[0013] (4) In the medical device of the above aspect, the second fixing portion may fix the first coil body and the second coil body.
[0014] According to this configuration, the second fixing portion fixes the first coil body and the second coil body, thereby improving the torque transmission performance of the medical device.
[0015] (5) In the medical device of the above aspect, the second fixing portion may fix the core shaft and the first coil body.
[0016] According to this configuration, the second fixing portion fixes the core shaft and the first coil body, thereby improving the torque transmission performance of the medical device.
[0017] (6) In the medical device of the above form, one or two of the first coil body, the second coil body, and the third coil body may be wound in a first winding direction, and the remaining coil body may be wound in a second winding direction different from the first winding direction.
[0018] According to this configuration, the coil bodies are wound in different directions, thereby improving torque transmission performance regardless of the rotation direction of the medical device.
[0019] (7) In the medical device of the above aspect, the bending stiffness of the second coil body may be greater than the bending stiffness of the first coil body.
[0020] According to this configuration, the bending rigidity of the second coil body is high, so that bending that occurs in the medical device can be further prevented from spreading toward the base end side of the medical device.
[0021] (8) One aspect of the present invention is a medical device comprising a core shaft, a first coil body arranged to surround a distal end of the core shaft, and a second coil body arranged radially outward of the first coil body, the distal end of the second coil body being located between the distal end and the base end of the first coil body in the axial direction of the core shaft, and a fixing part fixing the vicinity of the distal end of the second coil body and the first coil body, the axial position of the distal end of the fixing part being located between the outer periphery and the inner periphery of the second coil body being the axial position of the distal end of the fixing part being the axial position of the distal end of the second coil body and a fixed portion which is at the same axial position as the tip of the second coil body or closer to the base end than the axial position of the tip of the second coil body, and the core shaft has a straight portion which has an outer diameter which is approximately constant in the axial direction of the core shaft, and a tapered portion which is provided closer to the base end than the straight portion and whose outer diameter increases from the tip side to the base end side in the axial direction of the core shaft, and the axial position of the tip of the fixed portion in a portion which is located between the outer circumference and inner circumference of the second coil body is the same as the axial position of the tip of the tapered portion or closer to the base end than the axial position of the tip of the tapered portion.
[0022] According to this configuration, the distal end of the fixed portion is located at the same level as the distal end of the second coil body or closer to the proximal end than the distal end of the second coil body, thereby preventing bending of the medical device from spreading toward the proximal end. Also, the distal end of the fixed portion is located at the same level as the distal end of the tapered portion or closer to the proximal end than the distal end of the tapered portion, thereby preventing bending of the medical device from spreading toward the proximal end.
[0023] The present invention can be realized in various aspects, for example, in the form of a guidewire, a method for manufacturing a guidewire, a method for manufacturing a catheter, an endoscope, a dilator, and the like.
[0024] FIG. 1 is an explanatory diagram illustrating the overall configuration of a medical device of a first embodiment. FIG. 2 is an explanatory diagram illustrating the AA cross section of FIG. 1. FIG. 3 is an explanatory diagram illustrating a first fixing portion. FIG. 4 is an explanatory diagram illustrating the bending rigidity of a medical device of a first embodiment. FIG. 5 is an explanatory diagram illustrating the first fixing portion of a medical device of a conventional example. FIG. 6 is an explanatory diagram illustrating the bending rigidity of a medical device of a conventional example. FIG. 7 is an explanatory diagram illustrating a method for measuring bending rigidity. FIG. 8 is an explanatory diagram illustrating the first fixing portion of a medical device of a second embodiment. FIG. 9 is an explanatory diagram illustrating the first fixing portion of a medical device of a third embodiment. FIG. 10 is an explanatory diagram illustrating the first fixing portion of a medical device of a fourth embodiment. FIG. 11 is an explanatory diagram illustrating the first fixing portion of a medical device of a fifth embodiment. FIG. 12 is an explanatory diagram illustrating the first fixing portion of a medical device of a sixth embodiment. FIG. 13 is an explanatory diagram illustrating the distal end of a medical device of a seventh embodiment.
[0025] First Embodiment FIG. 1 is an explanatory diagram illustrating the overall configuration of a medical device 1 according to a first embodiment. FIG. 2 is an explanatory diagram illustrating a cross section taken along line A-A in FIG. 1 . The medical device 1 according to the first embodiment will be described with reference to FIGS. 1 to 4. Here, the medical device 1 will be described as a guidewire used to insert a medical instrument such as a catheter into a blood vessel or the like, as an example. The medical device 1 includes a first coil body 10, a second coil body 20, a third coil body 30, a core shaft 40, a first fixing portion 50, a second fixing portion 60, a third fixing portion 70, a fourth fixing portion 80, a distal fixing portion 100, and a proximal fixing portion 110. While FIGS. 1 and 3 are diagrams illustrating longitudinal cross sections of the components constituting the medical device 1, the outline of the core shaft 40 is shown. In the following examples, the medical device 1 will be described as being used in blood vessels, but the medical device 1 can be inserted into biological lumens such as the lymphatic system, biliary system, urinary system, respiratory system, digestive system, secretory glands, and reproductive organs, and can be used in addition to the vascular system.
[0026] In FIG. 1 , the axis passing through the center of the medical device 1 is represented by axis O (dotted line). In the example of FIG. 1 , axis O coincides with the axis passing through the centers of the first to third coil bodies (10, 20, 30) and the core shaft 40. However, axis O may differ from the central axis of each of the above-mentioned components. FIG. 1 illustrates mutually orthogonal X, Y, and Z axes. The X axis corresponds to the axial direction of the medical device 1, the Y axis corresponds to the height direction of the medical device 1, and the Z axis corresponds to the width direction of the medical device 1. The left side (−X axis direction) of FIG. 1 is referred to as the “distal side” of the medical device 1 and each component, and the right side (+X axis direction) of FIG. 1 is referred to as the “proximal side” of the medical device 1 and each component. Furthermore, of the two ends of the medical device 1 and each component in the axial direction (X axis direction), the one end located on the distal side is referred to as the “distal end,” and the other end located on the proximal side is referred to as the “proximal end.” The distal end and its vicinity are referred to as the "distal portion," and the proximal end and its vicinity are referred to as the "proximal end portion." The distal end is inserted into the living body, and the proximal end is operated by an operator such as a doctor. These points are also common to Figure 1 and subsequent figures.
[0027] 1, the core shaft 40 has an elongated outer shape extending along the axis O. The core shaft 40 has, from the tip to the base end, a straight portion 41, a tapered portion 42, and a large-diameter portion 43.
[0028] The straight portion 41 is disposed at the most distal end of the core shaft 40. The straight portion 41 is elongated and extends coaxially with the axis O of the medical device 1. The outer diameter of the straight portion 41 is approximately constant along the axis O. The distal end of the straight portion 41 is fixed to the first coil body 10 and the third coil body 30 by a distal-side fixing portion 100. A tapered portion 42 is connected to the proximal end of the straight portion 41, and a large-diameter portion 43 is connected to the proximal end of the tapered portion 42.
[0029] The straight portion 41 is a member that facilitates the surgeon's curved shape when forming the distal end of the medical device 1, and is also called a "ribbon." The straight portion 41 may have a flattened cross section to facilitate the surgeon's curved shape. For example, although not shown, the straight portion 41 may have a cross-sectional shape in which the maximum length in the Y-axis direction is different from the maximum length in the Z-axis direction. Specifically, the cross-sectional shape of the straight portion 41 may be a rectangle or an ellipse in which the maximum length in the Z-axis direction is longer than the maximum length in the Y-axis direction.
[0030] The tapered portion 42 is disposed between the straight portion 41 and the large-diameter portion 43. The tapered portion 42 is a generally truncated cone-shaped portion whose outer diameter increases from the distal end toward the proximal end in the axial direction of the core shaft 40. The straight portion 41 is connected to a distal end 44 of the tapered portion 42, and the large-diameter portion 43 is connected to a proximal end of the tapered portion 42. An example of a cross section of the tapered portion 42 is shown in Figure 2. The cross section of the tapered portion 42 is circular.
[0031] The thick-diameter portion 43 is located at the base end side of the core shaft 40. The thick-diameter portion 43 is a generally cylindrical portion having a generally constant outer diameter from the base end to the tip. The outer diameter of the thick-diameter portion 43 is the same as the thickest diameter portion of the tapered portion 42. In this embodiment, "same" means roughly the same, and allows for differences due to manufacturing errors, etc. The tapered portion 42 is connected to the tip of the thick-diameter portion 43. The base end of the thick-diameter portion 43 is grasped and operated by the surgeon.
[0032] The material of the core shaft 40 is not particularly limited, but examples thereof include stainless steel (SUS302, SUS304, SUS316, etc.), superelastic alloys (also called "pseudoelastic alloys") such as Ni-Ti alloys, piano wire, nickel-chromium alloys, cobalt alloys, platinum, gold, tungsten, etc. The straight portion 41, tapered portion 42, and large-diameter portion 43 may be made of the same material, or may be made of different materials.
[0033] <First coil body 10> The first coil body 10, the second coil body 20, and the third coil body 30 are arranged on the outer periphery of the core shaft 40 in this order from the radially inner side to the radially outer side of the medical device 1. The first coil body 10 is a coil body formed of eight wires 11 wound helically in the axial direction of the medical device 1. The first coil body 10 is arranged to surround the distal end of the core shaft 40. Specifically, the first coil body 10 is arranged to surround the straight portion 41 of the core shaft 40 and a portion of the distal side of the tapered portion 42. The distal end of the first coil body 10 is fixed to the core shaft 40 and the third coil body 30 by a distal-side fixing portion 100. The base end of the first coil body 10 is fixed to the core shaft 40 by a third fixing portion 70.
[0034] The first coil body 10 is wound in a first winding direction S shown in Fig. 2. The first winding direction S is a clockwise rotation direction around an axis O passing through the center of the medical device 1, from the viewpoint of observing the medical device 1 from the distal end side to the proximal end side (in other words, in the +X-axis direction).
[0035] <Second Coil Body 20> The second coil body 20 is a coil body formed by eight wires 21 wound helically in the axial direction of the medical device 1. The second coil body 20 is disposed radially outward of the first coil body 10 from the medical device 1, and surrounds a portion of the tapered portion 42 and a portion of the first coil body 10. In the axial direction of the medical device 1, the distal end 24 of the second coil body 20 is located between the distal end and proximal end of the first coil body 10. The distal end 24 of the second coil body 20 is fixed to the first coil body 10 and the core shaft 40 by a first fixing portion 50. In addition, in the axial direction of the medical device 1, the proximal end of the second coil body 20 is located closer to the proximal end than the proximal end of the first coil body 10. An intermediate portion of the second coil body 20 located between the distal end 24 and proximal end of the second coil body 20 is fixed to the first coil body 10, the third coil body 30, and the core shaft 40 by a second fixing portion 60. The proximal end of the second coil body 20 is fixed to the core shaft 40 by a fourth fixing portion 80. The second coil body 20 is wound in a first winding direction S shown in Fig. 2. In other words, the winding directions of the first coil body 10 and the second coil body 20 are the same.
[0036] As shown in FIG. 2 , the second coil body 20 has an inner circumference 22 and an outer circumference 23. The inner circumference 22 is a substantially cylindrical portion formed by connecting the inner sides of a plurality of spirally wound wires 21. The outer circumference 23 is a substantially cylindrical portion formed by connecting the outer sides of a plurality of spirally wound wires 21. In this embodiment, the outer circumference of the first coil body 10 and the inner circumference 22 of the second coil body 20 are in contact with each other, and the outer circumference 23 of the second coil body 20 and the inner circumference of the third coil body 30 are in contact with each other. However, the outer circumference of the first coil body 10 and the inner circumference 22 of the second coil body 20 may be spaced apart, and the outer circumference 23 of the second coil body 20 and the inner circumference of the third coil body 30 may be spaced apart.
[0037] The bending rigidity of the second coil body 20 is greater than the bending rigidity of the first coil body 10. A method for measuring the bending rigidity will be described later.
[0038] <Third Coil Body 30> The third coil body 30 is a coil body formed by a single wire 31 wound helically in the axial direction of the medical device 1. The third coil body 30 is disposed radially outward of the second coil body 20 from the medical device 1, and surrounds a portion of the core shaft 40 (in this embodiment, the straight portion 41 and a portion on the distal side of the tapered portion 42), the first coil body 10, and the second coil body 20. In the axial direction of the medical device 1, the distal end of the third coil body 30 is located at the same position as the distal end of the first coil body 10. The distal end of the third coil body 30 is fixed to the core shaft 40 and the first coil body 10 by a distal-side fixing portion 100. In addition, in the axial direction of the medical device 1, the proximal end of the third coil body 30 is located closer to the proximal end than the proximal end of the second coil body 20. The proximal end of the third coil body 30 is fixed to the core shaft 40 by a proximal-side fixing portion 110.
[0039] The third coil body 30 is wound in a second winding direction Z shown in Fig. 2. The second winding direction Z is a counterclockwise rotation direction around an axis O passing through the center of the medical device 1, from the viewpoint of observing the medical device 1 from the distal end side to the proximal end side (in other words, in the +X-axis direction).
[0040] Any configuration can be adopted for the first to third coil bodies (10, 20, 30). For example, the number of wires (11, 21, 31) constituting the first to third coil bodies (10, 20, 30) can be determined arbitrarily. The first coil body 10 and the second coil body 20 are not limited to multi-strand coils, and may be single-strand coils formed by winding a single wire, single-strand stranded coils formed by winding a stranded wire obtained by twisting together multiple wires, or multi-strand stranded coils formed by using multiple stranded wires obtained by twisting together multiple wires and winding each strand multiple times. Alternatively, the first to third coil bodies (10, 20, 30) may be tubes having a substantially cylindrical shape.
[0041] The material of the first to third coil bodies (10, 20, 30) is not particularly limited, but may be, for example, a stainless steel alloy such as SUS304 or SUS316, a superelastic alloy such as a NiTi alloy, a radiolucent alloy such as piano wire, a nickel-chromium alloy or a cobalt alloy, or a radiopaque alloy such as gold, platinum, tungsten, or an alloy containing these elements (e.g., a platinum-nickel alloy). The first to third coil bodies (10, 20, 30) may be made of the same material or different materials.
[0042] <Fixing Sections> The core shaft 40, the first coil body 10, the second coil body 20, and the third coil body 30 that constitute the medical device 1 are fixed by a plurality of fixing sections. The medical device 1 has, in order from the distal end of the medical device 1, a distal fixing section 100, a first fixing section 50, a second fixing section 60, a third fixing section 70, a fourth fixing section 80, and a proximal fixing section 110.
[0043] The distal-side fixed portion 100 is disposed at the distal end of the third coil body 30 and fixes the distal end of the third coil body 30, the distal end of the core shaft 40, and the distal end of the first coil body 10. The proximal-side fixed portion 110 is disposed at the proximal end of the third coil body 30 and fixes the proximal end of the third coil body 30 and a portion of the tapered portion 42. The first fixed portion 50 is disposed at the distal end 24 of the second coil body 20 and fixes the distal end 24 of the second coil body 20 and a portion of the first coil body 10. The second fixed portion 60 is disposed at the intermediate portion of the second coil body 20 and fixes the first coil body 10, the second coil body 20, the third coil body 30, and the core shaft 40. The third fixed portion 70 is disposed at the proximal end of the first coil body 10 and fixes the proximal end of the first coil body 10 and a portion of the tapered portion 42. The fourth fixing portion 80 is disposed at the base end of the second coil body 20 and fixes the base end of the second coil body 20 and a part of the tapered portion 42 .
[0044] 2, the first fixed portion 50 is formed between the outer periphery of the core shaft 40 and the outer periphery 23 of the second coil body 20. A specific portion 51, which is a part of the first fixed portion 50, is formed between the inner periphery 22 and the outer periphery 23 of the second fixed portion 60. Details of the first fixed portion 50 will be described later.
[0045] The distal fixed portion 100, the proximal fixed portion 110, the first fixed portion 50, the second fixed portion 60, the third fixed portion 70, and the fourth fixed portion 80 can be formed using any bonding agent, such as a metal solder such as silver solder, gold solder, zinc, an Sn—Ag alloy, or an Au—Sn alloy, or an adhesive such as an epoxy adhesive. The distal fixed portion 100, the proximal fixed portion 110, the first fixed portion 50, the second fixed portion 60, the third fixed portion 70, and the fourth fixed portion 80 may be formed using the same bonding agent or different bonding agents. Note that the distal fixed portion 100, the proximal fixed portion 110, the first fixed portion 50, the second fixed portion 60, the third fixed portion 70, and the fourth fixed portion 80 may be formed by laser welding.
[0046] <Details of First Fixed Portion 50> Figure 3 is an explanatory diagram illustrating the first fixed portion 50. The first fixed portion 50 fixes the vicinity of the tip 24 of the second coil body 20, the core shaft 40, and the first coil body 10. The vicinity of the tip 24 of the second coil body 20 refers to the tip portion of the second coil body 20 that extends a predetermined distance from the tip 24 toward the base end of the second coil body 20 (toward the +X-axis direction). The aforementioned "predetermined distance" refers to, for example, a distance in the axial direction of the second coil body 20 equivalent to one to approximately ten strands of wire 21 (distance in the +X-axis direction) in a longitudinal cross section of the second coil body 20 as shown in Figure 3.
[0047] Here, the portion of the first fixed portion 50 located between the inner circumference 22 and the outer circumference 23 of the second coil body 20 is referred to as the "specific portion 51." More specifically, the specific portion 51 is the portion of the first fixed portion 50 located between the radially innermost portion of the inner circumference 22 and the radially outermost portion of the outer circumference 23 of the second coil body 20. Imaginary lines 22L and 23L are shown in FIG. 3 . The imaginary line 22L is a line that virtually connects the radially innermost portion of the inner circumference 22. The imaginary line 23L is a line that virtually connects the radially outermost portion of the outer circumference 23. "Location between the inner circumference 22 and the outer circumference 23 of the second coil body 20" can be rephrased as "location between the imaginary lines 22L and 23L." The specific portion 51 is formed in the gap between adjacent wires 21 in the axial direction of the second coil body 20 or along the outer periphery of the wires 21. The portion of this specific portion 51 located closest to the distal end is referred to as the "distal end 52." In this case, the axial position of the distal end 52 of the specific portion 51 is the same as the axial position of the distal end 24 of the second coil body 20, or is located closer to the proximal end than the axial position of the distal end 24 of the second coil body 20. As a result, as will be described later, a portion where the bending rigidity of the medical device 1 changes significantly is formed at the distal end 24 of the second coil body 20, and bending on the distal side of the medical device 1 can be prevented from expanding (progressing) toward the proximal end beyond the distal end 24 of the second coil body 20. Furthermore, the axial position of the distal end 52 of the specific portion 51 is the same as the axial position of the distal end 44 of the tapered portion 42, or is located closer to the proximal end than the axial position of the distal end 44 of the tapered portion 42. As a result, as will be described later, a portion where the bending rigidity of the medical device 1 changes significantly is formed at the distal end 24 of the second coil body 20, and bending on the distal side of the medical device 1 can be prevented from expanding (progressing) toward the proximal end beyond the distal end 24 of the second coil body 20.
[0048] FIG. 4 is an explanatory diagram illustrating the bending stiffness 200 of the medical device 1 in the axial direction of the medical device 1. The horizontal axis of FIG. 4 represents the distance from the tip of the medical device 1, and the vertical axis represents the bending stiffness 200 of the medical device 1 at that position. An "axial position 241" in FIG. 4 indicates the axial position of the tip 24 of the second coil body 20. An "axial position 521" in FIG. 4 indicates the axial position of the tip 52 of the specific portion 51. Here, the axial position 241 and the axial position 521 are the same position in the axial direction of the medical device 1. With respect to the bending stiffness 200, the bending stiffness 202 on the base end side increases sharply compared to the bending stiffness 201 on the tip end side at the axial position 241. The bending stiffness 202 on the base end side of the axial position 241 is larger by an increase width w1 compared to the bending stiffness 201 on the tip end side of the axial position 241. The increase w1 in the bending stiffness 200 occurs when the bending stiffness of the second coil body 20 and the bending stiffness of the specific portion 51 are added to the bending stiffness 201 of the medical device 1. Furthermore, the bending stiffness 202 on the base end side gradually increases toward the base end because the outer diameter of the tapered portion 42 of the core shaft 40 increases toward the base end.
[0049] FIG. 5 is an explanatory diagram illustrating a longitudinal cross section of a conventional medical device 1Z. The components constituting the medical device 1Z, except for the first fixing portion 50Z, are common to the components constituting the medical device 1 of the first embodiment, and therefore will not be described here. The distal end 52Z of the specific portion 51Z of the medical device 1Z differs from the specific portion 51 of the medical device 1 in that it is located distal to the distal end 24 of the second coil body 20. A portion of the specific portion 51 formed distal to the distal end 24 of the second coil body 20 is referred to as a "protrusion 55Z." The protrusion 55Z is formed to fill the space between the outer periphery of the first coil body 10 and the inner periphery of the third coil body 30, distal to the distal end 24 of the second coil body 20. Meanwhile, the specific portion 51Z other than the protrusion 55Z is formed to follow the outer periphery of the wire 21 of the second coil body 20. As a result, the volume of the protrusion 55Z is larger than the volume of the specific portion 51Z other than the protrusion 55Z. The bending rigidity of the protrusion 55Z is also greater than the bending rigidity of the specific portion 51Z other than the protrusion 55Z.
[0050] FIG. 6 is an explanatory diagram illustrating the bending rigidity 200Z of the medical device 1Z in the axial direction of the medical device 1Z. The "axial position 241" in FIG. 6 indicates the axial position of the tip 24 of the second coil body 20. The "axial position 521Z" in FIG. 6 indicates the axial position of the tip 52Z of the specific portion 51. Here, the axial position 241 and the axial position 521Z are different positions in the axial direction of the medical device 1. The protrusion 55Z is located between the axial position 241 and the axial position 521Z. As described above, the axial position 521Z of the tip 52 of the first fixing portion 50Z (the axial position of the tip of the protrusion 55Z) is located further distally than the axial position 241 of the tip 24 of the second coil body 20. As a result, the bending rigidity 200Z increases distally from the axial position 241 of the tip 24 of the second coil body 20. Specifically, the bending stiffness 203 on the proximal side of the axial position 521Z is greater than the bending stiffness 201Z on the distal side of the axial position 521Z by the amount (increase w2) of the bending stiffness of the protrusion 55Z added to the bending stiffness 200Z. Meanwhile, the increase in the bending stiffness 200Z across the axial position 241 is smaller than the increase w1 ( FIG. 4 ) of the medical device 1. Specifically, the bending stiffness 202Z on the proximal side of the axial position 241 and the bending stiffness 203 on the distal side of the axial position 241 differ only by the increase (increase w3) due to the bending stiffness of the second coil body 20. In other words, in the medical device 1 of the first embodiment shown in FIG. 4 , the bending stiffness 200 increases sharply across the distal end 24 of the second coil body 20, whereas in the conventional medical device 1Z, the bending stiffness 200Z increases stepwise near the distal end 24 of the second coil body 20. Therefore, in the conventional medical device 1Z, the rigidity of the medical device 1 does not change significantly at the tip 24 of the second coil body 20, so there is a risk that the bending at the tip side of the medical device 1 will expand (progress) toward the base end beyond the tip 24 of the second coil body 20.
[0051] <Method for Measuring Bending Rigidity> FIG. 7 is an explanatory diagram illustrating a method for measuring bending rigidity. In this embodiment, bending rigidity is measured by a cantilever beam test, which will be described with reference to FIG. 7 . Specifically, as shown in FIG. 7(A), a measurement object 5 is supported using a gripping tool 4. The load sensor 3 of the measuring device 2 is placed in contact with an arbitrary location on the measurement object 5 protruding from the gripping tool 4. At this time, a predetermined distance a is set between the contact point P between the measurement object 5 and the load sensor 3 and the end face of the gripping tool 4 (the end face facing the measuring device 2). In this state, as shown in FIG. 7(B), the contact point P is used as the point of force, and the gripping tool 4 is lowered a predetermined amount in the direction of the arrow in the figure. Then, the measurement value of the load sensor 3 when the gripping tool 4 reaches a predetermined displacement y is taken as the bending rigidity of the measurement object 5.
[0052] According to the medical device 1 of the first embodiment described above, the axial position of the tip 52 of the specific portion 51 is set to the same position as the axial position of the tip 24 of the second coil body 20. As a result, as shown in Fig. 4, the bending rigidity 200 of the medical device 1 increases sharply at the tip 24 of the second coil body 20, and bending that occurs in the medical device 1 can be prevented from expanding from the tip 24 of the second coil body 20 toward the base end side.
[0053] 5 and 6, a protrusion 55Z is formed by arranging the tip 52Z of the specific portion 51Z distal to the tip 24 of the second coil body 20. As a result, as shown in Fig. 6, the increase in bending rigidity 200Z in the axial direction of the medical device 1Z from the bending rigidity (201Z) on the distal side, with the tip 24 of the second coil body 20 as the boundary, to the bending rigidity (202Z) on the proximal side is smaller than that of the medical device 1. In the guidewire 1Z, the bending rigidity 200Z changes stepwise near the tip 24 of the second coil body 20, making it difficult to prevent bending that occurs on the distal side of the medical device 1Z from expanding toward the proximal side from the tip 24 of the second coil body 20. On the other hand, since the medical device 1 has a large difference between the magnitude of the bending rigidity 201 distal to the tip 24 of the second coil body 20 and the magnitude of the bending rigidity 202 proximal to the tip 24 of the second coil body 20, it is possible to prevent bending that occurs on the distal side of the medical device 1 from expanding toward the proximal side from the tip 24 of the second coil body 20. Furthermore, according to the medical device 1 of the first embodiment, the axial position of the tip 52 of the specific portion 51 is the same as the axial position of the tip 44 of the tapered portion 42, or is located closer to the proximal side than the axial position of the tip 44 of the tapered portion 42. As a result, at the tip 24 of the second coil body 20, a portion of the core shaft 40 where the bending rigidity of the medical device 1 changes significantly is formed closer to the proximal side than the tip 44 of the tapered portion 42, which has a bending rigidity greater than that of the straight portion 41. Since bending is more suppressed in areas with higher bending rigidity, by forming the part of the core shaft 40 where the bending rigidity of the medical device 1 changes significantly in a part where the bending rigidity is relatively high, bending at the tip end of the medical device 1 can be further suppressed from expanding (progressing) toward the base end beyond the tip 24 of the second coil body 20.
[0054] The medical device 1 has a second fixing portion 60 that fixes the core shaft 40, the first coil body 10, the second coil body 20, and the third coil body 30 on the proximal side of the first fixing portion 50. This improves torque transmission performance.
[0055] The first coil body 10 and the second coil body 20 are wound in a first winding direction S, and the third coil body 30 is wound in a second winding direction Z. In other words, of the first coil body 10, the second coil body 20, and the third coil body 30, two coil bodies are wound in the first winding direction S, and the remaining coil body is wound in the second winding direction Z. By winding the respective coil bodies in different directions, torque transmission performance is improved regardless of the rotation direction of the medical device 1.
[0056] The bending rigidity of the second coil body 20 is greater than the bending rigidity of the first coil body 10. This more reliably prevents bending that occurs in the medical device 1 from spreading from the distal end 24 of the second coil body 20 toward the base end side.
[0057] The tip 52 of the specific portion 51 of the first fixing portion 50 is disposed at the same position as the tip 44 of the tapered portion 42 of the core shaft 40. This makes it possible to further increase the bending rigidity 202 on the base end side of the tip 24 of the second coil body 20, and more reliably suppress bending that occurs in the medical device 1 from expanding toward the base end side of the tip 24 of the second coil body 20.
[0058] 8 is an explanatory diagram illustrating a first fixing portion 50B of a medical device 1B of a second embodiment. The medical device 1B differs from the medical device 1 of the first embodiment in that the distal end 52B of the first fixing portion 50B is located closer to the proximal end than the distal end 24 of the second coil body 20. Description of the configuration of the medical device 1B that is common to the medical device 1 of the first embodiment will be omitted.
[0059] Since the second coil body 20 is disposed closer to the base end than the tip 24 of the tip 20 of the second coil body 20, the bending rigidity of the medical device 1B on the base end side than the axial position of the tip 24 of the second coil body 20 increases sharply compared to the bending rigidity of the medical device 1B on the tip end side. This makes it possible to prevent bending that occurs in the medical device 1B from expanding toward the base end side beyond the tip 24 of the second coil body 20.
[0060] 9 is an explanatory diagram illustrating a first fixing portion 50C of a medical device 1C of a third embodiment. The medical device 1C differs from the medical device 1 of the first embodiment in that the first fixing portion 50C is not in contact with the core shaft 40 and fixes only the first coil body 10 and the second coil body 20. A description of the configuration of the medical device 1C that is common to the medical device 1 of the first embodiment will be omitted.
[0061] In the medical device 1C of the third embodiment, the bending rigidity of the medical device 1C on the proximal side of the axial position of the tip 24 of the second coil body 20 also increases sharply compared to the bending rigidity of the medical device 1C on the distal side, thereby making it possible to prevent bending that occurs in the medical device 1C from expanding toward the proximal side of the tip 24 of the second coil body 20.
[0062] 10 is an explanatory diagram illustrating an enlarged view of a first fixing portion 50D of a medical device 1D of a fourth embodiment. The medical device 1D differs from the medical device 1C of the third embodiment in that the first fixing portion 50D is disposed closer to the base end than the distal end 24 of the second coil body 20. Description of the configuration of the medical device 1D that is common to the medical device 1C of the third embodiment will be omitted.
[0063] In the medical device 1D of the fourth embodiment, the bending rigidity of the medical device 1D on the proximal side of the axial position of the tip 24 of the second coil body 20 also increases sharply compared to the bending rigidity of the medical device 1D on the distal side, thereby making it possible to prevent bending that occurs in the medical device 1D from expanding toward the proximal side of the tip 24 of the second coil body 20.
[0064] 11 is an explanatory diagram illustrating a first fixing portion 50E of a medical device 1E of a fifth embodiment. The medical device 1E differs from the medical device 1 of the first embodiment in that the tip 54 of the portion of the first fixing portion 50E that is disposed between the outer and inner circumferences of the first coil body 10 (hereinafter referred to as the specific portion 53) is located closer to the tip side than the tip 24 of the second coil body 20. Description of the configuration of the medical device 1E that is common to the medical device 1 of the first embodiment will be omitted.
[0065] As described above, in this embodiment, the tip 54 of the specific portion 53 is disposed distally of the tip 24 of the second coil body 20. As a result, the bending rigidity of the medical device 1E distal to the tip 24 of the second coil body 20 increases by the bending rigidity of the specific portion 53. However, because the specific portion 53 is merely formed thinly along the outer periphery of the wire 11 of the first coil body 10, the increase in bending rigidity of the medical device 1E is small. Therefore, in the medical device 1E, the bending rigidity of the medical device 1E proximal to the axial position of the tip 24 of the second coil body 20 increases sharply compared to the bending rigidity of the medical device 1E distal to the tip 24 of the second coil body 20. This makes it possible to prevent bending that occurs in the medical device 1E from expanding proximally beyond the tip 24 of the second coil body 20.
[0066] 12 is an explanatory diagram illustrating a first fixing portion 50F of a medical device 1F of a sixth embodiment. The medical device 1F differs from the medical device 1 of the first embodiment in that the distal end 24F of the second coil body 20F and the distal end 52F of the first fixing portion 50F are located closer to the proximal end than the distal end 44 of the tapered portion 42. Description of the configuration of the medical device 1F that is common to the medical device 1 of the first embodiment will be omitted.
[0067] In the medical device 1F of the sixth embodiment, the bending rigidity of the medical device 1F on the proximal side of the axial position of the tip 24F of the second coil body 20F also increases sharply compared to the bending rigidity of the medical device 1F on the distal side, thereby making it possible to prevent bending that occurs in the medical device 1F from expanding toward the proximal side of the tip 24F of the second coil body 20F.
[0068] 13 is an explanatory diagram illustrating the distal end of a medical device 1G according to a seventh embodiment. The medical device 1G differs from the medical device 1 according to the first embodiment in that it does not have a third coil 30. A description of the components of the medical device 1G that are common to the medical device 1 according to the first embodiment will be omitted.
[0069] In the medical device 1G of the seventh embodiment, the bending rigidity of the medical device 1G on the proximal side of the axial position of the tip 24 of the second coil body 20 also increases sharply compared to the bending rigidity of the medical device 1G on the distal side, thereby making it possible to prevent bending that occurs in the medical device 1G from expanding toward the proximal side of the tip 24 of the second coil body 20.
[0070] <Modifications> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the invention. For example, the following modifications are also possible.
[0071] <Modification 1> The axial lengths of the straight portion 41, the tapered portion 42, and the thick-diameter portion 43 can be determined arbitrarily. For example, in the first and seventh embodiments, the axial length of the straight portion 41 was smaller than the axial length of the tapered portion 42. However, the axial length of the straight portion 41 may be greater than the axial length of the tapered portion 42. Furthermore, the cross-sectional shapes of the straight portion 41, the tapered portion 42, and the thick-diameter portion 43 can be determined arbitrarily. For example, in the first embodiment, the cross-sections of the straight portion 41, the tapered portion 42, and the thick-diameter portion 43 were circular. However, the cross-sections of the straight portion 41, the tapered portion 42, and the thick-diameter portion 43 may be elliptical or polygonal, such as triangular or rectangular.
[0072] <Modification 2> The medical devices (1, 1B, 1C, 1D, 1E, 1F, 1G) of the first to seventh embodiments may further have a resin coating on the outer periphery of the third coil body 30 or the second coil body (20, 20F).
[0073] <Modification 3> The second fixing portion 60 may fix the first coil body 10, the second coil body (20, 20F), and the third coil body 30, but may not fix the core shaft 40. The second fixing portion 60 may fix the second coil body (20, 20F) and the third coil body 30, but may not fix the core shaft 40, and may not fix the first coil body 10.
[0074] REFERENCE SIGNS LIST 1... Medical device 10... First coil body 11... Wire of first coil body 20... Second coil body 21... Wire of second coil body 22... Inner circumference of second coil body 23... Outer circumference of second coil body 24... Tip of second coil body 30... Third coil body 31... Wire of third coil body 40... Core shaft 41... Straight portion 42... Tapered portion 43... Large diameter portion 44... Tip of tapered portion 50... First fixing portion 51... Specific portion 52... Tip of first fixing portion 60... Second fixing portion 70... Third fixing portion 80... Fourth fixing portion 100... Tip side fixing portion 110... Base end side fixing portion S... First winding direction Z... Second winding direction
Claims
1. It is a medical device, Core shaft and A first coil body is arranged surrounding the tip of the core shaft, A second coil body positioned radially outward from the first coil body, wherein, in the axial direction of the core shaft, the tip of the second coil body is located between the tip and base of the first coil body, A fixing portion for fixing the tip of the second coil body and the first coil body, wherein the axial position of the tip of the fixing portion in the portion located between the outer and inner circumferences of the second coil body is the same as the axial position of the tip of the second coil body, or is closer to the base end than the axial position of the tip of the second coil body, The core shaft has a straight section in which the outer diameter is substantially constant in the axial direction of the core shaft, It has a tapered portion provided closer to the base end than the straight portion, and the outer diameter of the core shaft increases from the tip end to the base end in the axial direction of the core shaft, A medical device in which the axial position of the tip of the second coil body is the same as the axial position of the tip of the tapered portion, or is closer to the proximal end than the axial position of the tip of the tapered portion.
2. A medical device according to claim 1, The fixing part is a medical device that fixes the core shaft and the first coil body.
3. A medical device according to claim 1 or claim 2, The aforementioned fixing part is the first fixing part, The aforementioned medical device further, A third coil body is positioned radially outward from the second coil body, A medical device comprising a second fixing portion that fixes the second coil body and the third coil body, located on the proximal end side of the first fixing portion.
4. A medical device according to claim 3, The second fixing part is a medical device that fixes the first coil body and the second coil body.
5. A medical device according to claim 4, The second fixing part is a medical device that fixes the core shaft and the first coil body.
6. A medical device according to claim 3, A medical device in which one or two of the first coil, the second coil, and the third coil are wound in a first winding direction, and the remaining coils are wound in a second winding direction different from the first winding direction.
7. A medical device according to claim 1 or claim 2, A medical device in which the bending rigidity of the second coil body is greater than that of the first coil body.
8. It is a medical device, Core shaft and A first coil body is arranged surrounding the tip of the core shaft, A second coil body positioned radially outward from the first coil body, wherein, in the axial direction of the core shaft, the tip of the second coil body is located between the tip and base of the first coil body, A fixing portion for fixing the tip of the second coil body and the first coil body, wherein the axial position of the tip of the fixing portion in the portion located between the outer and inner circumferences of the second coil body is the same as the axial position of the tip of the second coil body, or is closer to the base end than the axial position of the tip of the second coil body, The core shaft has a straight section in which the outer diameter is substantially constant in the axial direction of the core shaft, It has a tapered portion provided closer to the base end than the straight portion, and the outer diameter of the core shaft increases from the tip end to the base end in the axial direction, Of the fixing portion, the axial position of the tip of the fixing portion in the portion located between the outer and inner circumferences of the second coil body is the same as the axial position of the tip of the tapered portion, or is closer to the base end than the axial position of the tip of the tapered portion. A medical device in which the axial position of the tip of the second coil body is the same as the axial position of the tip of the tapered portion, or is closer to the proximal end than the axial position of the tip of the tapered portion.