WO2020084677A1 - Hollow coil, dilator, and guide wire - Google Patents

Abstract

This hollow coil has a taper section wherein the coil external diameter becomes smaller from one end to the other end of the hollow coil, the taper section being formed in such a manner that the degree by which the coil external diameter is reduced becomes smaller from the one end to the other end.

Description

Hollow coil, dilator, and guide wire

The present invention relates to a hollow coil, a dilator, and a guide wire.

Conventionally, a medical guide wire including a hollow coil formed by winding a metal wire is known. For example, Patent Document 1 discloses a guide wire in which a hollow coil is attached to the tip side of a core shaft.

Japanese Patent Publication No. 2003-505116

Such a guide wire is inserted into a blood vessel, for example, in the treatment of expanding the diameter of a blood vessel lesion, and is pushed into the blood vessel until the tip of the guide wire reaches the blood vessel lesion. At this time, a phenomenon called a kink in which the guide wire is bent may occur in a blood vessel having a tortuous and complicated path or in a branched blood vessel portion. In particular, when the hollow coil attached to the guide wire is provided with a taper part where the coil outer diameter changes, a rigidity gap where the bending rigidity of the hollow coil changes greatly near the taper part is apt to occur, and stress is applied to that part. However, there was a problem that kink was likely to occur due to concentration. It should be noted that such a problem is not limited to a guide wire having a hollow coil, and is the same in a medical device having a hollow coil such as a dilator, a catheter, or an endoscope which is inserted into a blood vessel or digestive organ of a human body. Occurs.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a technique for suppressing the occurrence of kinks in the vicinity of the tapered portion of a hollow coil attached to a medical device.

The present invention has been made to solve at least a part of the above problems, and can be realized as the following modes.

(1) According to one aspect of the present invention, a hollow coil is provided. The hollow coil has a taper portion whose coil outer diameter decreases from one end side of the hollow coil toward the other end side thereof, and the taper portion is provided from the one end side of the hollow coil. It is formed so that the degree of decrease in the outer diameter of the coil decreases toward the other end side.

According to this structure, the taper portion is formed so that the degree of decrease in the coil outer diameter decreases from one end side toward the other end side. Is less likely to occur. Therefore, in the medical device using this hollow coil, when it is inserted into a blood vessel or digestive organ of a human body, stress is less likely to be concentrated in the vicinity of the tapered portion of the hollow coil, and the occurrence of kinks can be suppressed.

(2) In the hollow coil of the above configuration, the degree of decrease of the coil outer diameter in the tapered portion may be set so that the bending rigidity linearly changes in at least a part of the tapered portion. With this configuration, it is possible to further reduce the occurrence of a bending gap of bending rigidity near the tapered portion. The medical device using this hollow coil can further suppress the occurrence of kinks when stress is concentrated in the vicinity of the tapered portion of the hollow coil when inserted into a blood vessel or digestive organ of the human body.

(3) The hollow coil of the above aspect may further have a constant diameter portion having a constant coil outer diameter between the tapered portion and the one end of the hollow coil. With this configuration, a rigid gap is unlikely to occur between the tapered portion and the other end of the hollow coil. Therefore, in the case of a medical device using this hollow coil, when it is inserted into a blood vessel or digestive organ of the human body, a kink occurs due to the concentration of stress between the tapered portion and the other end of the hollow coil. Can be suppressed.

(4) In the hollow coil of the above configuration, the tapered portion may be formed by a wire having a constant outer diameter. According to this configuration, since it is possible to suppress the change in bending rigidity due to the change in the wire diameter, it is possible to further reduce the occurrence of a bending gap in bending rigidity near the tapered portion. The medical device using this hollow coil can further suppress the occurrence of kinks when stress is concentrated in the vicinity of the tapered portion of the hollow coil when inserted into a blood vessel or digestive organ of the human body.

(5) According to another aspect of the present invention, a dilator is provided. This dilator includes the hollow coil of the above-described embodiment and a connector connected to the base end of the hollow coil. According to this configuration, the tapered portion of the hollow coil is formed so that the degree of decrease in the coil outer diameter decreases from one end side toward the other end side, so that the bending rigidity near the tapered portion Rigidity gap is unlikely to occur. Therefore, when the dilator is inserted into a blood vessel of a human body, stress is less likely to be concentrated in the vicinity of the tapered portion of the hollow coil, and the occurrence of kinks can be suppressed.

(6) According to another aspect of the present invention, a guide wire is provided. The guide wire includes a hollow coil of the above-described embodiment, a core shaft at least a part of which is arranged inside the hollow coil, a distal end of the core shaft, and a distal end joining portion at which a distal end of the hollow coil is joined. A core end and a base end joint part where the base end of the hollow coil is joined. According to this configuration, the tapered portion of the hollow coil is formed so that the degree of decrease in the coil outer diameter decreases from one end side toward the other end side, so that the bending rigidity near the tapered portion Rigidity gap is unlikely to occur. Therefore, when the guide wire is inserted into a blood vessel or digestive organ of a human body, stress is less likely to be concentrated in the vicinity of the tapered portion of the hollow coil, and the occurrence of kinks can be suppressed.

The present invention can be realized in various modes, for example, in the form of an endoscope including a hollow coil, a hollow coil manufacturing apparatus, a hollow coil manufacturing method, and the like.

It is explanatory drawing which illustrated the whole structure of the hollow coil of 1st Embodiment. It is the figure which illustrated the AA cross section of FIG. 1 in a hollow coil. It is explanatory drawing which illustrated the detailed structure of a taper part. It is a figure for demonstrating the shape of the hollow coil of a comparative example. It is a figure for demonstrating the coil pitch of the hollow coil of a comparative example, the strand length per pitch, and the reciprocal of the strand length per pitch. It is a figure for demonstrating the bending rigidity of the hollow coil of a comparative example. It is a figure for demonstrating the shape of the hollow coil of this embodiment. It is a figure for demonstrating the coil pitch of the hollow coil of this embodiment, the strand length per pitch, and the reciprocal of the strand length per pitch. It is a figure for demonstrating the bending rigidity of the hollow coil of this embodiment. It is explanatory drawing which illustrated the structure of the sample of the hollow coil used for the bending test. It is a figure for demonstrating the test method of a bending test. It is the figure which showed the relationship between the pitch expansion ratio and the measured bending rigidity. It is the figure which showed the relationship between the strand length per unit length, and the measured bending rigidity. It is explanatory drawing which illustrated the whole structure of the dilator of 2nd Embodiment. It is explanatory drawing which illustrated the whole structure of the dilator of 3rd Embodiment. It is explanatory drawing which illustrated the whole structure of the guide wire of 4th Embodiment. It is explanatory drawing which illustrated the whole structure of the guide wire of 5th Embodiment. It is explanatory drawing which illustrated the whole structure of the guide wire of 6th Embodiment. It is explanatory drawing which illustrated the partial structure of the hollow coil of 7th Embodiment. It is explanatory drawing which illustrated the partial structure of the hollow coil of 8th Embodiment.

<First Embodiment>
FIG. 1 is an explanatory diagram illustrating the overall configuration of the hollow coil 1 according to the first embodiment. FIG. 2 is a view exemplifying the AA cross section of the hollow coil 1 in FIG. The hollow coil 1 is, for example, a spiral structure used for a part of medical equipment such as a dilator, a guide wire, a catheter, and an endoscope, and has a hollow and substantially cylindrical outer shape. Hereinafter, the left side (the tip side opening 17 side) of FIG. 1 is called the “tip side” of the hollow coil 1, and the right side (the base end side opening 19 side) of FIG. 1 is the “base end side” of the hollow coil 1. Call.

As shown in FIG. 1, the hollow coil 1 has a tapered long outer diameter in which the proximal end side has a large diameter and the distal end side has a small diameter, and in order from the distal end side to the proximal end side, It has a small diameter portion 11, a taper portion 12, and a large diameter portion 13. As shown in FIGS. 1 and 2, the hollow coil 1 includes ten metal wires 15 (first wire 15a, second wire 15b, third wire 15c, fourth wire 15d, and fifth wire 15d). Hollow stranded wire coil in which a twisted wire formed by twisting the wire 15e, the sixth wire 15f, the seventh wire 15g, the eighth wire 15h, the ninth wire 15i, and the tenth wire 15j) is formed into a cylindrical shape. And a lumen 16 is formed inside. As shown in FIG. 1, a distal end side opening 17 communicating with the inner cavity 16 is formed at the distal end of the hollow coil 1, and a proximal end side opening communicating with the inner cavity 16 is formed at the proximal end of the hollow coil 1. 19 is formed. The length of the hollow coil 1 is not particularly limited, but for example, a range of 1 mm to 3000 mm can be exemplified.

The small-diameter portion 11 is a hollow cylindrical portion having the smallest coil outer diameter in the hollow coil 1, and the coil pitch and the coil outer diameter are constant from the distal end to the proximal end of the hollow coil 1. The coil pitch of the small-diameter portion 11 is not particularly limited, but here, the coil pitch is a dense winding in which the adjacent wires 15 are densely wound so as to come into contact with each other. The outer diameter of the coil of the small diameter portion 11 is not particularly limited, but may be, for example, in the range of 0.1 mm to 2.0 mm. The length of the small diameter portion 11 is also not particularly limited, but for example, a range of 0.1 mm to 500 mm can be exemplified.

The tapered portion 12 is a tapered hollow portion formed between the small-diameter portion 11 and the large-diameter portion 13, and the outer diameter of the coil decreases from the proximal end side to the distal end side. The tapered portion 12 is formed so that the degree of decrease in the coil outer diameter decreases from the base end side toward the tip end side. The taper portion 12 is formed so that the coil pitch increases from the base end side toward the tip end side. That is, the coil pitch of the tapered portion 12 increases as the coil outer diameter decreases. The taper portion 12 is closely wound so that the adjacent wires 15 are in close contact with each other. The coil pitch on the proximal end side of the tapered portion 12 is substantially equal to the coil pitch of the large diameter portion 13, and the coil pitch on the distal end side of the tapered portion 12 is substantially equal to the coil pitch of the small diameter portion 11. The length of the tapered portion 12 is not particularly limited, but for example, a range of 0.1 mm to 100 mm can be exemplified. The detailed configuration of the tapered portion 12 will be described later with reference to FIG.

The large-diameter portion 13 is a hollow cylindrical portion in which the coil outer diameter is maximum in the hollow coil 1, and the coil pitch and the coil outer diameter are constant from the base end of the hollow coil 1 toward the tip side. The coil pitch of the large diameter portion 13 is smaller than the coil pitch of the small diameter portion 11. The coil pitch of the large-diameter portion 13 is not particularly limited, but here, it is densely wound such that the adjacent wires 15 are densely wound so as to come into contact with each other. The outer diameter of the coil of the large-diameter portion 13 is not particularly limited, but may be, for example, a range of 0.2 mm to 3.0 mm. The length of the large-diameter portion 13 is also not particularly limited, but for example, a range of 1 mm to 3000 mm can be exemplified.

The wire 15 is a wire member having a solid circular cross section and is made of a metal material. As the metal material, for example, a stainless alloy (SUS304, SUS316, etc.) can be adopted. The outer diameter (strand diameter) of the strand 15 is constant in all of the small diameter portion 11, the tapered portion 12, and the large diameter portion 13. The wire diameter of the wire 15 is not particularly limited, but may be, for example, in the range of 0.01 mm to 3 mm.

FIG. 3 is an explanatory diagram illustrating the detailed configuration of the taper portion 12. Here, the tapered portion 12 is divided into five at equal intervals along the axial direction of the hollow coil 1, and the “first section N1”, the “second section N2”, and the “second section N2” are sequentially arranged from the base end side to the tip end side. These are referred to as "third section N3", "fourth section N4", and "fifth section N5". Further, the coil outer diameter of the tapered portion 12 at the base end (point P0) of the first section N1 is D0, the coil outer diameter at the boundary between the first section N1 and the second section N2 (point P1) is D1, the second section The coil outer diameter at the boundary (point P2) between N2 and the third section N3 is D2, the coil outer diameter at the boundary (point P3) between the third section N3 and the fourth section N4 is D3, and the fourth section N4 and the fifth. The coil outer diameter at the boundary with the section N5 (point P4) is called D4, and the coil outer diameter at the tip of the fifth section N5 (point P5) is called D5. FIG. 3 shows a virtual line IML connecting the upper ends and the lower ends of the coil outer diameters D0 to D5.

The tapered portion 12 of the hollow coil 1 of the present embodiment has a coil outer diameter that decreases in order from a side having a relatively large coil outer diameter (base end side) to a side having a relatively small coil outer diameter (tip end side). Has become. That is, the coil outer diameters D0 to D5 are configured to satisfy D0> D1> D2> D3> D4> D5. In the present embodiment, as an example for explaining the configuration of the taper portion 12, the taper portion 12 is divided into five at equal intervals, but the taper portion 12 is divided into a number other than 5 at equal intervals. Even if there is, the outer diameter of the coil in each section may be reduced from the base end side toward the tip end side.

Further, here, the decrease amount of the coil outer diameter (coil outer diameter D0-coil outer diameter D1) in the first section N1 (between the P0 point and the P1 point) is A1, and the second section N2 (P1 point to the P2 point). The coil outer diameter reduction amount (coil outer diameter D1-coil outer diameter D2) is A2, and the coil outer diameter reduction amount (coil outer diameter) in the third section N3 (between P2 point and P3 point) D2-coil outer diameter D3) is A3, and the reduction amount of coil outer diameter in the fourth section N4 (between points P3 and P4) (coil outer diameter D3-coil outer diameter D4) is A4 and fifth section N5 ( The amount of decrease in the coil outer diameter (between the points P4 and P5) (coil outer diameter D4−coil outer diameter D5) is A5.

The tapered portion 12 of the hollow coil 1 according to the present embodiment has a degree of decrease in the coil outer diameter from the side having a relatively large coil outer diameter (base end side) to the side having a relatively small coil outer diameter (tip end side). Is formed to be small. That is, the reduction amounts A1 to A5 of the outer diameter of the coil are configured such that A1> A2> A3> A4> A5. As described above, in the present embodiment, as an example for explaining the configuration of the tapered portion 12, the tapered portion 12 is divided into five at equal intervals, but the tapered portion 12 is divided into a number other than 5 at equal intervals. Even in such a case, the degree of decrease in the coil outer diameter in each section may be reduced from the base end side toward the tip end side.

In the tapered portion 12 of the present embodiment, the degree of decrease in the coil outer diameter decreases from the side having a relatively large coil outer diameter (base end side) to the side having a relatively small coil outer diameter (tip end side). Therefore, the amount of change in bending rigidity of the hollow coil 1 in the vicinity of the tapered portion 12 can be brought close to a constant value. The reason for this will be described below.

<Bending rigidity of hollow coil>
The hollow coil can be considered as a bundle of a plurality of wires. Therefore, the bending rigidity EI of the hollow coil is proportional to the number N of strands of the wire forming the hollow coil and the second moment of inertia I _w of the wire. The geometrical moment of inertia I _w of a wire having a round cross section can be expressed by the following equation (1).

^{_{I w = π · d 4/}} 64 ··· (1)
Here, d represents the wire diameter [mm].

The bending stiffness EI of the hollow coil is proportional to the number N of the strands of the coil as described above, and is further proportional to the fourth power of the strand diameter d from Equation (1). On the other hand, the inventors of the present invention have shown that the actually-measured bending rigidity EI of the hollow coil is inversely proportional to the strand length M [mm] per unit length of the hollow coil in the hollow coil bending test described later. I found it. That is, the present inventors have found that the bending rigidity EI of the hollow coil can be expressed by the following equation (2).

EI = α ・ d ⁴・ N / M (2)
Here, α represents a coefficient, d represents a strand diameter [mm], N represents the number of strands [pieces], and M represents a strand length per unit length of the coil.

The strand length M per unit length of the coil can be expressed by the following formula (3) using the coil pitch P [mm] and the strand length R [mm] per pitch.

M = R / P ... (3)

From equations (2) and (3), the bending rigidity EI of the hollow coil can be expressed by the following equation (4).

EI = β ・ d ⁴・ N ・ P / R ・ ・ ・ (4)
Here, β represents a coefficient, d represents a wire diameter, N represents the number of threads, P represents a coil pitch, and R represents a wire length per pitch.
The coil pitch P is the distance (the size of one pitch) between the same strands in the axial direction in the hollow coil composed of a plurality of strands. The strand length R per pitch is the length required for one strand forming the hollow coil to be wound along the circumferential direction of the hollow coil to form one pitch.

<Bending rigidity of taper part>
Bending rigidity of the tapered portion of the hollow coil will be described with reference to FIGS. Here, the relationship between the shape of the tapered portion and the bending rigidity will be described based on the difference in bending rigidity between the two types of hollow coils having different shapes of the tapered portion. One of the two types of hollow coils is the hollow coil of the present embodiment, and the other is the hollow coil as a comparative example.

One of the hollow coils (hollow coil of the present embodiment) has a plurality of wires made of a metal material, and is provided with a thin-diameter portion on the front end side, a large-diameter portion on the base end side, and between the small-diameter portion and the large-diameter portion. The hollow coil is formed by spirally winding the first cored bar having a tapered portion and then removing the cored bar. The other hollow coil (hollow coil of the comparative example) has a plurality of wires made of a metal material, which are formed by tapering a thin-diameter portion on the distal end side, a large-diameter portion on the proximal end side, and a thin-diameter portion and a large-diameter portion. A hollow coil formed by spirally winding a second cored bar having a portion by the same winding method as in the case of one hollow coil, and then removing the cored bar. The first cored bar and the second cored bar differ only in the shape of the tapered portion. In the tapered portion of the first core metal, the shape of the vertical cross section thereof becomes smaller in a curved shape that is convex toward the axis of the first core metal as it goes from the larger diameter portion to the smaller diameter portion. In other words, the degree of decrease of the outer diameter becomes smaller from the larger diameter portion toward the smaller diameter portion. In the tapered portion of the second core metal, the shape of the vertical cross section thereof decreases in a substantially linear shape from the large diameter portion toward the small diameter portion. In other words, the degree of decrease of the outer diameter becomes substantially constant from the large diameter portion to the small diameter portion.

The two hollow coils differ only in the shape of the taper part. That is, the two hollow coils consist of the material of the wire, the number of wires, the wire diameter, the coil outer diameter and inner diameter of the small diameter portion, the coil pitch of the thin diameter portion, and the coil outer diameter and inner diameter of the large diameter portion. , And the coil pitches of the large diameter portion are equal to each other. Both of these two hollow coils have a constant wire diameter from the base end to the tip, and in both of them, the coil pitch of the small diameter portion is larger than the coil pitch of the large diameter portion. The two hollow coils have a constant coil pitch in both the thin diameter portion and the large diameter portion, and in the tapered portion, both have a larger coil pitch from the base end side toward the tip end side. . The two hollow coils are densely wound from the base end to the tip so that adjacent wires are closely wound to each other. On the other hand, the two hollow coils differ from each other in the coil pitch of the tapered portion and the strand length per pitch in the tapered portion due to the different shapes of the tapered portions.

FIG. 4 is a diagram for explaining the shape of the hollow coil of the comparative example. The horizontal axis of FIG. 4 shows the position in the longitudinal direction of the hollow coil of the comparative example, and the vertical axis shows the coil outer diameter at that position. As shown in FIG. 4, the hollow coil of the comparative example has a thin portion having a relatively small coil outer diameter on the tip side, and a large diameter portion and a thin portion having a relatively large coil outer diameter on the base end side. And a large diameter portion, a taper portion having a coil outer diameter that decreases from the base end side toward the tip end side is provided. In the tapered portion of this comparative example, the coil outer diameter decreases from the base end side to the tip end side in a substantially linear shape. In other words, in the tapered portion of the comparative example, the degree of decrease in the coil outer diameter is substantially constant.

FIG. 5 illustrates the coil pitch P (solid line) of the hollow coil of the comparative example, the strand length R per pitch (dashed line), and the reciprocal 1 / R of the strand length per pitch (dotted line). FIG. The horizontal axis of FIG. 5 indicates the position in the longitudinal direction of the hollow coil of the comparative example, and the vertical axis indicates the coil pitch P at that position, the strand length R per pitch, and the strand length per pitch. The reciprocal of 1 / R is shown.

As shown in FIG. 5, in the hollow coil of the comparative example, the coil pitch P is constant in the small diameter portion on the tip side and the large diameter portion on the base end side, and the coil pitch P of the small diameter portion is larger. It is larger than the coil pitch P of the part. Further, in the taper portion between the small diameter portion and the large diameter portion, the coil pitch P increases in a downward convex curved shape from the base end side toward the tip end side. In other words, in the tapered portion, the degree of increase in the coil pitch P increases from the base end side toward the tip end side.

As shown in FIG. 5, in the hollow coil of the comparative example, the wire length R per pitch is constant in the small-diameter portion on the tip side and the large-diameter portion on the base end side, and one pitch of the small-diameter portion is used. The strand length R per area is shorter than the strand length R per pitch in the large diameter portion. Further, in the taper portion between the small diameter portion and the large diameter portion, the strand length R per pitch decreases in a substantially linear shape from the base end side toward the tip end side. This is because the influence of the coil outer diameter is larger (predominant) than the influence of the coil pitch P on the strand length R per pitch.

As shown in FIG. 5, in the hollow coil of the comparative example, the reciprocal 1 / R of the wire length per pitch is constant in the small-diameter portion on the tip side and the large-diameter portion on the base end side. The reciprocal 1 / R of the wire length per pitch of 1 is larger than the reciprocal 1 / R of the wire length per pitch of the large diameter portion. In the taper portion between the small diameter portion and the large diameter portion, the reciprocal 1 / R of the strand length per pitch increases in a downward convex curve shape from the base end side toward the tip end side. There is. In other words, in the tapered portion, the reciprocal 1 / R of the strand length per pitch increases with increasing distance from the base end side to the tip end side.

FIG. 6 is a diagram for explaining the bending rigidity of the hollow coil of the comparative example. The horizontal axis of FIG. 6 shows the position in the longitudinal direction of the hollow coil of the comparative example, and the vertical axis shows the bending rigidity at that position. As shown in FIG. 6, the bending rigidity of the small diameter part is higher than the bending rigidity of the large diameter part. Further, the bending rigidity of the tapered portion has an inversely proportional curved shape (curve shape on the positive side of the hyperbola). In other words, in the tapered portion of the comparative example, the degree of increase in bending rigidity increases from the base end side toward the tip end side. The reason why the bending rigidity of the hollow coil of the comparative example is as shown in FIG. 6 will be described later. In the hollow coil of the comparative example, since the bending rigidity of the tapered portion has an inversely proportional curved shape, there is a rigidity gap in which the bending rigidity changes rapidly near the boundary between the small diameter portion and the tapered portion. If a rigidity gap is generated in the bending rigidity of the hollow coil, when an external force is applied to the hollow coil, stress is concentrated on the portion where the rigidity gap is generated, and a kink is likely to occur.

The reason why the bending rigidity of the hollow coil of the comparative example becomes as shown in FIG. 6 will be described. As described above, the bending rigidity EI of the hollow coil can be calculated by the above equation (4). The wire diameter d and the number of threads N of the hollow coil of the comparative example are constant regardless of the longitudinal position of the coil. Therefore, the bending rigidity EI of the hollow coil is proportional to the product of the coil pitch P and the reciprocal 1 / R of the strand length per pitch. As shown in FIG. 5, the coil pitch P of the small diameter part of the hollow coil of the comparative example is larger than the coil pitch P of the large diameter part. Further, the coil pitch P of the taper portion increases in a downward convex curve shape from the base end side (large diameter portion side) toward the tip end side (small diameter portion side). In other words, in the taper portion, the degree of increase in the coil pitch P increases from the base end side toward the tip end side. In addition, the reciprocal 1 / R of the strand length per pitch in the small diameter portion of the hollow coil of the comparative example is larger than the reciprocal 1 / R of the strand length per pitch in the large diameter portion. In the taper part, the reciprocal 1 / R of the strand length per pitch becomes a convex curve downward from the base end side (large diameter part side) to the tip end side (small diameter part side). It has increased. In other words, in the tapered portion, the reciprocal 1 / R of the strand length per pitch increases with increasing distance from the base end side to the tip end side.
Therefore, as described above, the bending rigidity EI of the hollow coil is proportional to the product of the coil pitch P and the reciprocal 1 / R of the strand length per pitch. As shown, the bending rigidity EI of the small diameter portion and the large diameter portion is constant, and the bending rigidity EI of the small diameter portion is higher than the bending rigidity EI of the large diameter portion. Further, the bending rigidity EI of the taper portion increases in a downward convex curved shape from the base end side (large diameter portion side) toward the tip end side (small diameter portion side), that is, the inverse proportional positive side. It becomes the curved shape (the curved shape on the positive side of the hyperbola). In other words, in the taper portion, the degree of increase in bending rigidity EI becomes larger from the base end side toward the tip end side.

FIG. 7 is a diagram for explaining the shape of the hollow coil of this embodiment. The horizontal axis of FIG. 7 shows the longitudinal position of the hollow coil of the present embodiment, and the vertical axis shows the coil outer diameter at that position. As shown in FIG. 7, the hollow coil of the present embodiment is provided with a small-diameter portion having a relatively small coil outer diameter on the distal end side and a relatively small coil outer diameter on the proximal end side, like the hollow coil of the comparative example. The large diameter portion is provided with a relatively large diameter, and the tapered portion is provided between the small diameter portion and the large diameter portion so that the coil outer diameter decreases from the base end side toward the tip end side. In the tapered portion of the present embodiment, the outer shape of the coil decreases in a convex curved shape toward the axis of the hollow coil from the base end side toward the tip end side. In other words, in the taper portion of the present embodiment, the degree of decrease in the coil outer diameter becomes smaller from the base end side toward the tip end side.

FIG. 8 shows the coil pitch P (solid line) of the hollow coil of the present embodiment, the strand length R per pitch (broken line), and the reciprocal 1 / R of the strand length per pitch (dotted line). It is a figure for explaining. The horizontal axis of FIG. 8 represents the position in the longitudinal direction of the hollow coil of the present embodiment, and the vertical axis represents the coil pitch P at that position, the strand length R per pitch, and the strand per pitch. The magnitude of the reciprocal 1 / R of the length is shown.

As shown in FIG. 8, in the hollow coil of the present embodiment, the coil pitch P is constant in the small diameter portion on the tip side and the large diameter portion on the base end side, and the coil pitch P of the small diameter portion is larger. It is larger than the coil pitch P of the diameter portion. Further, in the taper portion between the small diameter portion and the large diameter portion, the coil pitch P increases in a substantially linear shape from the base end side toward the tip side, or the coil pitch P can be regarded as a substantially linear shape. It gradually increases in a downward convex curve. In other words, in the taper portion, the degree of increase in the coil pitch P becomes substantially constant as it goes from the base end side to the tip end side, or the degree of increase in the coil pitch P becomes gentle enough to be regarded as substantially constant. It is getting bigger.

As shown in FIG. 8, in the hollow coil of the present embodiment, the wire length R per pitch is constant in the small-diameter portion on the tip side and the large-diameter portion on the base end side. The strand length R per pitch is shorter than the strand length R per pitch of the large diameter portion. Further, in the taper portion between the small diameter portion and the large diameter portion, the strand length R per pitch decreases in a downward convex curve shape from the base end side toward the tip end side. In other words, the degree of decrease in the strand length R per pitch becomes smaller from the base end side toward the tip end side. This is similar to the case of the hollow coil of the comparative example, in which the effect of the coil outer diameter is greater than the effect of the coil pitch P on the strand length R per pitch (which is dominant). This is because.

As shown in FIG. 8, in the hollow coil of the present embodiment, the reciprocal 1 / R of the strand length per pitch is constant in the small diameter portion on the distal end side and the large diameter portion on the proximal end side. The reciprocal 1 / R of the strand length per pitch of the portion is larger than the reciprocal 1 / R of the strand length per pitch of the large diameter portion. In the taper portion between the small diameter portion and the large diameter portion, the reciprocal 1 / R of the strand length per pitch increases in a substantially straight line from the base end side toward the tip end side, or 1 pitch The reciprocal 1 / R of the length of the strand is gradually increased to a curved shape that is convex upward to the extent that it can be regarded as a substantially linear shape. In other words, in the taper portion, the reciprocal 1 / R of the strand length per pitch is substantially constant as it goes from the base end side to the tip end side, or The degree of increase of the reciprocal 1 / R of the line length is gradually decreased to such an extent that it can be regarded as substantially constant.

FIG. 9 is a diagram for explaining the bending rigidity of the hollow coil of the present embodiment. The horizontal axis of FIG. 9 indicates the longitudinal position of the hollow coil of the present embodiment, and the vertical axis indicates the bending rigidity at that position. Similar to the hollow coil of the comparative example, also in the hollow coil of this embodiment, the bending rigidity of the small diameter portion is higher than the bending rigidity of the large diameter portion. On the other hand, unlike the hollow coil of the comparative example, the bending rigidity of the tapered portion has a substantially linear shape (a substantially linear shape). In other words, in the tapered portion of the present embodiment, the degree of increase in bending rigidity is substantially constant from the base end side toward the tip end side. The reason why the bending rigidity of the hollow coil of this embodiment becomes as shown in FIG. 9 will be described later. In the hollow coil of the present embodiment, since the bending rigidity of the tapered portion has a substantially linear shape (because it changes linearly), a change in bending rigidity near the boundary between the small diameter portion and the tapered portion is a comparative example (FIG. 6). It has become looser than. That is, according to the hollow coil of the present embodiment, even if the hollow coil is provided, the generation of the rigid gap near the tapered portion is suppressed. As a result, stress concentration is less likely to occur when the hollow coil receives an external force, and kink can be reduced.

The reason why the bending rigidity of the hollow coil of this embodiment becomes as shown in FIG. 9 will be described. Similar to the hollow coil of the comparative example, the bending rigidity EI of the hollow coil of the present embodiment can be calculated by the above equation (4). The wire diameter d and the number of threads N of the hollow coil of the present embodiment are constant regardless of the longitudinal position of the coil. Therefore, the bending rigidity EI of the hollow coil is proportional to the product of the coil pitch P and the reciprocal 1 / R of the strand length per pitch. As shown in FIG. 8, in the hollow coil of the present embodiment, the coil pitch P of the small diameter portion is larger than the coil pitch P of the large diameter portion, similarly to the hollow coil of the comparative example. In addition, the coil pitch P of the taper portion increases substantially linearly from the base end side (large diameter portion side) toward the tip end side (small diameter portion side), or is moderate to such an extent that it can be regarded as a substantially linear shape. It increases in a downward convex curve. In other words, in the taper portion, the degree of increase in the coil pitch P becomes substantially constant as it goes from the base end side to the tip end side, or the degree of increase in the coil pitch P becomes gentle enough to be regarded as substantially constant. It is getting bigger. Further, the reciprocal 1 / R of the wire length per pitch of the hollow coil of the present embodiment is larger in the small diameter portion than in the large diameter portion, as in the hollow coil of the comparative example. On the other hand, in the taper portion, the reciprocal 1 / R of the strand length per pitch increases in a substantially linear shape from the base end side (large diameter part side) to the tip end side (small diameter part side). , Or gradually increasing in a curved shape that is convex upward so that it can be regarded as a substantially straight shape. In other words, in the taper portion, the reciprocal 1 / R of the strand length per pitch is substantially constant as it goes from the base end side to the tip end side, or The degree of increase of the reciprocal 1 / R of the line length is gradually decreased to such an extent that it can be regarded as substantially constant.
Therefore, in the hollow coil of the present embodiment, the product of the coil pitch P and the reciprocal 1 / R of the strand length per pitch is constant in the small-diameter portion and the large-diameter portion, and the thin-diameter portion has a larger diameter. It is larger than the diameter part. It is considered that the tapered portion increases in a substantially linear shape from the base end side (large diameter portion side) toward the tip end side (small diameter portion side). As a result, as described above, since the bending rigidity EI of the hollow coil is proportional to the product of the coil pitch P and the reciprocal 1 / R of the strand length per pitch, as shown in FIG. In the hollow coil of the embodiment, the bending rigidity EI of the small diameter portion and the large diameter portion is constant, and the bending rigidity EI of the small diameter portion is higher than the bending rigidity EI of the large diameter portion. The bending rigidity EI of the taper portion increases substantially linearly from the base end side toward the tip end side. As described above, according to the hollow coil of the present embodiment, the bending rigidity can be made substantially linear. Note that the bending rigidity of the tapered portion of the present embodiment only needs to have a substantially linear shape, and does not need to have a linear shape as a whole as shown in FIG. 9. Further, for example, in the present embodiment, the bending rigidity of the tapered portion may be a linear shape only in a part including the vicinity of the boundary between the tapered portion and the small diameter portion. Even in these cases, it is possible to suppress the generation of the rigid gap near the boundary between the tapered portion and the small diameter portion.

<Hollow coil bending test>
With reference to FIGS. 10 to 13, it will be described that the bending rigidity EI of the hollow coil is inversely proportional to the strand length M per unit length of the coil as in the above equation (2). Here, in order to clarify the relationship between the wire length M per unit length of the hollow coil and the bending rigidity EI of the hollow coil, bending was performed on five hollow coil samples 1 to 5 having different coil pitches. The test was done.

FIG. 10 is an explanatory view illustrating the configurations of hollow coil samples 1 to 5 used in the bending test. Hollow coil samples 1 to 5 are obtained by expanding the coil pitch at different expansion ratios [%] with respect to hollow coils having the same structure. That is, in the hollow coil samples 1 to 5, the number N of strands (here, N = 1), the strand diameter d, and the strand length R per pitch are equal to each other, but only the coil pitch P is different. ing.

In Sample 1, the pitch expansion ratio was set to 119% with respect to the standard coil pitch of the hollow coil, and the strand length per 1 mm coil was set to 8.755 mm. In Sample 2, the pitch expansion ratio was 152%, and the strand length per 1 mm of the coil was 6.856 mm. In Sample 3, the pitch expansion ratio was 206%, and the strand length per 1 mm of the coil was 5.058 mm. In Sample 4, the pitch expansion ratio was 305% and the strand length per 1 mm of the coil was 3.415 mm. In Sample 5, the pitch expansion ratio was 377%, and the strand length per 1 mm of the coil was 2.755 mm.

FIG. 11 is a diagram for explaining the bending test method. Hollow coils SA of Samples 1 to 5 were set in order above the two fulcrums ST1 and ST2, a concentrated load W was applied to the center of each sample, and the displacement σ of the center was measured. The broken line SB shows the states of Samples 1 to 5 before the concentrated load W is applied. Using the measured displacement σ, the concentrated load W, and the distance L between the two fulcrums ST1 and ST2 (distance between fulcrums) L, the bending rigidity (measured bending rigidity) EI [N · mm] of the samples 1 to 5 is calculated. It was calculated.

When the center of the both-end support beam is weighted as in this bending test, the displacement amount σ of the central portion of the sample can be expressed by the following formula (5) using the concentrated load W and the fulcrum distance L.

^{σ = W · L 3/48} · EI ··· (5)
Here, EI represents the bending rigidity of the sample hollow coil.

From the formula (5), the actually measured bending rigidity EI of the sample hollow coil can be calculated by the following formula (6) using the displacement amount σ, the concentrated load W, and the inter-fulcrum distance L. Using this formula (6), the measured bending rigidity of Samples 1 to 5 was calculated.

^{EI = W · L 3/48} · σ ··· (6)

FIG. 12 is an explanatory diagram showing the relationship between the pitch expansion ratio [%] of Samples 1 to 5 and the measured bending rigidity EI. The horizontal axis of FIG. 12 represents the pitch expansion ratio of each sample, and the vertical axis represents the bending rigidity of each sample. It can be seen from FIG. 12 that the bending rigidity of each sample is proportional to the pitch expansion ratio. The Young's modulus E of each sample is the same, and the second moment of area I is almost the same although it varies slightly depending on the difference in twist angle. Therefore, as a theoretical value, which is the product of Young's modulus E and moment of inertia of area I, EI is almost the same in all of Samples 1 to 5. On the other hand, the sample arranged between the two fulcrums ST1 and ST2 as shown in FIG. 11 is subjected to an evenly distributed load due to its own weight. At this time, if the pitch expansion ratio is small, the weight per unit length increases. In other words, the evenly distributed load on the sample increases. Therefore, it is considered that when the pitch expansion ratio is small, the displacement amount σ becomes large and the measured EI decreases. From the above, it is considered that the bending rigidity of each sample is proportional to the pitch expansion ratio.

FIG. 13 is an explanatory diagram showing the relationship between the strand length [mm] per 1 mm coil of Samples 1 to 5 and the measured bending rigidity EI. The horizontal axis of FIG. 13 represents the strand length per 1 mm of the coil of each sample, and the vertical axis represents the bending rigidity of each sample. As shown in FIG. 13, it can be seen that the bending rigidity is inversely proportional to the length of the wire per 1 mm of the coil. As described above, it is considered that when the wire length per 1 mm of the coil is long, the self-weight per unit length increases and the actually measured bending rigidity EI decreases. From the result of FIG. 13, it has been clarified that the bending rigidity EI of the hollow coil is inversely proportional to the strand length M per unit length of the coil as in the above-mentioned formula (2).

<Example of effect of the present embodiment>
According to the hollow coil 1 of the present embodiment described above, the taper portion 12 has a coil outer diameter that decreases from the base end side where the coil outer diameter is relatively large toward the tip end side where the coil outer diameter is relatively small. It is formed so that the degree is small (FIG. 3). As a result, the bending rigidity of the tapered portion can be made closer to a linear shape, and the bending rigidity rigidity gap can be less likely to occur near the boundary between the tapered portion 12 and the small diameter portion 11 (FIG. 9). Therefore, in the medical device using the hollow coil 1 of the present embodiment, when it is inserted into a blood vessel or a digestive organ of a human body, stress is less likely to be concentrated in the vicinity of the tapered portion 12 of the hollow coil 1 and kink is prevented. Can be suppressed.

Further, according to the hollow coil 1 of the present embodiment, the degree of decrease of the coil outer diameter in the tapered portion 12 is set so that the bending rigidity linearly changes in at least a part of the tapered portion 12 (FIG. 9). ). If the bending rigidity of the taper portion is made closer to a linear shape by adjusting the degree of decrease of the coil outer diameter in the taper portion 12, the rigidity gap of the bending rigidity is further increased near the boundary between the taper portion 12 and the small diameter portion 11. It can be made difficult to occur and the occurrence of kinks can be further suppressed.

Further, according to the hollow coil 1 of the present embodiment, since the tapered portion 12 and the proximal end of the hollow coil 1 have the large diameter portion 13 having a constant coil outer diameter, The bending rigidity between the hollow coil 1 and the base end can be made constant, and the occurrence of kinks in this section can be suppressed. Further, in the medical device using the hollow coil 1, since a step is less likely to occur on the proximal end side than the proximal end of the tapered portion 12, it is possible to prevent the medical device from being caught when it is inserted into a blood vessel or digestive organ of a human body. . Further, in the medical device using the hollow coil 1, the rotational force (torque) and the pushing force (pushability) from the procedure side can be transmitted to the taper portion 12 via the large diameter portion 13. As a result, even if the medical device is curved in the human body, it is possible to suppress deterioration of the transmission performance of these devices.

Further, according to the hollow coil 1 of the present embodiment, since the tapered portion 12 is formed by the wire 15 having a constant outer diameter, it is possible to suppress the occurrence of the rigidity gap due to the change in the wire diameter. Specifically, as shown in the above formula (2), the bending rigidity EI of the tapered portion 12 is proportional to the fourth power of the wire diameter. Therefore, if the strand diameter of the tapered portion 12 changes, the bending rigidity of the tapered portion 12 also changes, and a rigidity gap is likely to occur. According to the hollow coil 1 of the present embodiment, since the wire diameter of the tapered portion 12 is constant, it is possible to suppress the change in bending rigidity due to factors other than the change in coil outer diameter.

Conventionally, there is known a technique of changing rigidity by changing a tapered portion of a core shaft in a guide wire in a curved line (for example, Japanese Patent Publication No. 2003-505116). As can be seen from this conventional technique, it is generally considered that the tapered portion has a higher bending rigidity on the side having a larger outer diameter than on the side having a smaller outer diameter. However, the present inventors have found that in a hollow coil having a spiral structure, the taper portion has a smaller bending rigidity on the side having a larger coil outer diameter than on the side having a small outer diameter. Further, the inventors of the present invention have found that in the hollow coil, the taper portion has a smaller degree of decrease in the coil outer diameter from the base end side where the coil outer diameter is relatively large toward the tip end side where the coil outer diameter is relatively smaller. It was found that the bending rigidity of the taper portion approaches a linear shape by forming such a structure. Further, the inventors of the present invention have found that in the hollow coil, by making the bending rigidity of the tapered portion close to a linear shape, a rigidity gap of bending rigidity is less likely to occur near the tip end side of the tapered portion. For example, Japanese Patent Publication No. 2003-505116 does not describe anything about changing the outer diameter of the hollow coil, and therefore a person skilled in the art would not be able to conceive the configuration of the present application from the invention described in this publication. Rather, this publication describes that the tapered portion has higher bending rigidity on the side having a larger outer diameter than on the side having a smaller outer diameter, and therefore there is a technical impediment factor in arriving at the configuration of the present application. I can say.

<Second Embodiment>
FIG. 14 is an explanatory diagram illustrating the overall configuration of the dilator 2 of the second embodiment. Here, a dilator using the hollow coil 1 (FIG. 1) of the first embodiment will be described. The dilator 2 according to the second embodiment includes a hollow coil 20 and a connector 200. The hollow coil 20 has the same structure as the hollow coil 1 (FIG. 1) of the first embodiment. That is, the hollow coil 20 has a small-diameter portion 21, a taper portion 22, and a large-diameter portion 23 in order from the distal end side toward the proximal end side. The configurations of the small-diameter portion 21, the tapered portion 22, and the large-diameter portion 23 are similar to those of the small-diameter portion 11, the tapered portion 12, and the large-diameter portion 13 of the hollow coil 1 (FIG. 1) of the first embodiment. Therefore, the description is omitted.

The hollow coil 20 is a hollow stranded wire coil in which a stranded wire obtained by twisting 10 strands 25 (first strand 25a to 10th strand 25j) is formed into a cylindrical shape, and has an inner cavity inside. Has been formed. A distal end side opening portion 27 communicating with the inner cavity is formed at the distal end of the hollow coil 20, and a connector 200 is connected to the proximal end of the hollow coil 20. The connector 200 is a hollow member made of resin, and a base end side opening 209 communicating with the inner cavity is formed at the base end of the connector 200.

According to the dilator 2 of the present embodiment described above, the taper portion 22 has the taper portion 22 from the base end side (the large diameter portion 23 side) where the coil outer diameter is relatively large to the tip end side (thinner portion where the coil outer diameter is relatively small. It is formed so that the degree of decrease in the outer diameter of the coil becomes smaller toward the diameter portion 21 side (FIG. 14). As a result, the bending rigidity of the tapered portion 22 can be made closer to a linear shape, and a rigidity gap of bending rigidity can be less likely to occur near the boundary between the tapered portion 22 and the small diameter portion 21. Therefore, with the dilator 2 of the present embodiment, it is possible to suppress the occurrence of kinks due to stress concentration near the tapered portion 22 when the dilator 2 is inserted into a blood vessel or digestive organ of a human body.

❖ Conventionally, there is known a technique of expanding the diameter of a hole formed in the body of the patient or a part of the body surface by using a dilator. For example, when expanding the hole formed in a part of the patient's body using a dilator, first, the introduction needle is projected from the tip of the endoscope inserted through the patient's mouth or nose, and the stomach A puncture is made at a predetermined position on the wall of the digestive tract using an introduction needle, and a guide wire is inserted into the hole. Then, the distal end of the dilator is inserted into the proximal end of the guide wire, and the dilator is inserted into the wall of the digestive tract along the guide wire to expand the diameter of the hole formed in the wall of the digestive tract. Further, for example, in the case of expanding the diameter of the hole formed in a part of the body surface of the patient using a dilator, first, using a lead-in needle at a predetermined position on the skin of the patient, guide through the hole. Insert the wire into a body lumen such as a blood vessel. Then, the proximal end of the guide wire is inserted into the distal end of the sheath introducer having the sheath and the dilator inserted into the sheath, and the sheath introducer is inserted into the body lumen along the guide wire. At this time, the tip of the dilator expands the hole formed in the skin.

In dilators used for such procedures, for example, when expanding the diameter of a hole formed in the body of a patient or a part of the body surface, there may be a kink that causes the dilator to bend. In particular, when a hollow coil is provided in a part of the dilator and a taper portion is formed in the hollow coil, a rigidity gap in which the bending rigidity of the coil greatly changes is easily generated in the vicinity of the taper portion, and stress is generated in that portion. There was a problem that kink was likely to occur when concentrated. However, according to the dilator of the present embodiment, since the generation of the rigid gap can be reduced near the tapered portion of the hollow coil, the generation of kink near the tapered portion can be suppressed.

<Third Embodiment>
FIG. 15 is an explanatory diagram illustrating the overall configuration of the dilator 3 of the third embodiment. The dilator 3 of the third embodiment is different from the dilator 2 (FIG. 14) of the second embodiment in the shape of the hollow coil on the tip side. The dilator 3 according to the third embodiment includes a hollow coil 30, a connector 300, and a tip member 310. The hollow coil 30 has a tapered portion 32 and a large diameter portion 33, similarly to the hollow coil 1 (FIG. 1) of the first embodiment. On the other hand, the hollow coil 30 does not have a small diameter portion, unlike the hollow coil 1 (FIG. 1) of the first embodiment. The configurations of the tapered portion 32 and the large diameter portion 23 are the same as those of the tapered portion 12 and the large diameter portion 13 of the hollow coil 1 (FIG. 1) of the first embodiment, and therefore description thereof will be omitted.

The hollow coil 30 is a hollow stranded wire coil in which a stranded wire formed by twisting ten strands 35 (first strand 35a to tenth strand 35j) is formed into a cylindrical shape, and has an inner cavity inside. Has been formed. A tip member 310 is connected to the tip of the hollow coil 30, and a connector 300 is connected to the base end of the hollow coil 30. The tip member 310 is formed by pouring a brazing material (silver brazing, gold brazing, etc.) on the tip side of the hollow coil 30, and has a hollow and substantially cylindrical shape. A front end side opening 317 communicating with the inner cavity is formed at the front end of the front end member 310. The connector 300 is a hollow member made of resin, and a base end side opening 309 communicating with the inner cavity is formed at the base end of the connector 300.

According to the dilator 3 of the present embodiment described above, even if the hollow coil 30 does not have a small-diameter portion on the tip side of the tapered portion 32, the occurrence of kinks in the vicinity of the tapered portion 32 of the hollow coil 30. Can be suppressed. That is, also in the taper portion 32 of the present embodiment, the degree of decrease in the coil outer diameter decreases from the base end side where the coil outer diameter is relatively large toward the tip end side where the coil outer diameter is relatively small. (Fig. 15). As a result, the bending rigidity of the taper portion 32 can be made closer to a linear shape, and a rigidity gap of the bending rigidity near the taper portion 32 can be made less likely to occur. Therefore, with the dilator 3 of the present embodiment, it is possible to suppress the occurrence of kinks due to stress concentration near the tapered portion 32 when the dilator 3 is inserted into a blood vessel or digestive organ of a human body.

<Fourth Embodiment>
FIG. 16: is explanatory drawing which illustrated the whole structure of the guide wire 4 of 4th Embodiment. Here, a guide wire using the hollow coil 1 (FIG. 1) of the first embodiment will be described. The guide wire 4 of the fourth embodiment includes a hollow coil 40 and a core shaft 410.
The hollow coil 40 has the same structure as the hollow coil 1 (FIG. 1) of the first embodiment. That is, the hollow coil 40 has a tapered long outer diameter with a large diameter on the proximal end side and a small diameter on the distal end side. The hollow coil 40 has a small diameter portion 41 in order from the distal end side toward the proximal end side. , And a large diameter portion 43. The configurations of the small diameter portion 41, the tapered portion 42, and the large diameter portion 43 are similar to those of the small diameter portion 11, the tapered portion 12, and the large diameter portion 13 of the hollow coil 1 (FIG. 1) of the first embodiment. Therefore, the description is omitted.

The hollow coil 40 is a hollow stranded wire coil in which a stranded wire formed by twisting a plurality of strands is formed into a cylindrical shape, and an inner cavity is formed inside. The distal end side of the core shaft 410 is inserted into the inner cavity of the hollow coil 40. The tip end of the hollow coil 40 is fixed to the tip end of the core shaft 410 inserted into the hollow coil 40 by the tip joint portion 421. The base end of the hollow coil 40 is fixed to a part of the core shaft 410 by the base end joint 425.

According to the present embodiment described above, even in the guide wire 4 in which the hollow coil 40 covers a part of the core shaft 410, the bending rigidity of the tapered portion 42 can be made closer to a linear shape, and the distal end side of the tapered portion 42 It is possible to prevent a rigidity gap of bending rigidity from occurring in the vicinity. Therefore, with the guide wire 4 of the present embodiment, it is possible to suppress the occurrence of kinks when stress is concentrated near the tapered portion 42 of the hollow coil 40 when the guide wire 4 is inserted into a blood vessel or digestive organ of a human body.

<Fifth Embodiment>
FIG. 17: is explanatory drawing which illustrated the whole structure of the guide wire 5 of 5th Embodiment. The guide wire 5 of the fifth embodiment is different from the guide wire 4 of the fourth embodiment (FIG. 16) in the shape of the distal end side and the proximal end side of the hollow coil. The guide wire 5 of the fifth embodiment includes a hollow coil 50 and a core shaft 510. The hollow coil 50 has a tapered portion 52 as in the hollow coil 1 (FIG. 1) of the first embodiment. On the other hand, the hollow coil 50 does not have a small diameter part and a large diameter part, unlike the hollow coil 1 (FIG. 1) of the first embodiment. The configuration of the taper portion 42 is the same as that of the taper portion 12 of the hollow coil 1 (FIG. 1) of the first embodiment, and the description thereof will be omitted.

The hollow coil 50 is a hollow stranded wire coil in which a twisted wire formed by twisting a plurality of strands is formed into a cylindrical shape, and an inner cavity is formed inside. The distal end side of the core shaft 510 is inserted into the inner cavity of the hollow coil 50. The tip of the hollow coil 50 is fixed to the tip of the core shaft 510 inserted into the hollow coil 50 by the tip joint portion 521. The base end of the hollow coil 50 is fixed to a part of the core shaft 510 by the base end joint 525.

According to the guide wire 5 of the present embodiment described above, even if the hollow coil 50 does not have the small diameter portion and the large diameter portion on both sides of the tapered portion 52, the hollow coil 50 is close to the tapered portion 52. The occurrence of kinks can be suppressed. That is, also in the taper portion 52 of the present embodiment, the degree of decrease in the coil outer diameter decreases from the base end side where the coil outer diameter is relatively large toward the tip end side where the coil outer diameter is relatively small. (Fig. 17). As a result, the bending rigidity of the tapered portion 52 can be made closer to a linear shape, and a rigidity gap of bending rigidity can be less likely to occur in the vicinity of the tapered portion 52. Therefore, with the guide wire 5 of the present embodiment, it is possible to suppress the occurrence of kinks due to stress concentration near the tapered portion 52 when the guide wire 5 is inserted into a blood vessel or digestive organ of a human body.

<Sixth Embodiment>
FIG. 18: is explanatory drawing which illustrated the whole structure of the guide wire 6 of 6th Embodiment. The guide wire 6 of the sixth embodiment is different from the guide wire 4 of the fourth embodiment (FIG. 16) in the shape of the hollow coil, and the hollow coil covers the entire core shaft. The guide wire 6 of the sixth embodiment includes a hollow coil 60 and a core shaft 610. The hollow coil 60 has the same structure as the hollow coil 1 (FIG. 1) of the first embodiment. That is, the hollow coil 60 has a tapered long outer diameter in which the proximal end side has a large diameter and the distal end side has a small diameter, and the hollow coil 60 has a small diameter portion 61 in order from the distal end side to the proximal end side. , And a large diameter portion 63. The configurations of the small diameter portion 61, the tapered portion 62, and the large diameter portion 63 are similar to those of the small diameter portion 11, the tapered portion 12, and the large diameter portion 13 of the hollow coil 1 (FIG. 1) of the first embodiment. Therefore, the description is omitted.

The hollow coil 60 is a hollow twisted wire coil in which a twisted wire formed by twisting a plurality of strands is formed into a cylindrical shape, and an inner cavity is formed inside. A core shaft 610 is inserted into the inner cavity of the hollow coil 60. The tip of the hollow coil 40 is fixed to the tip of the core shaft 610 inserted into the hollow coil 60 by the tip joint portion 621. Further, the base end of the hollow coil 60 is fixed to the base end of the core shaft 610 by the base end joint portion 625.

According to the present embodiment described above, even in the guide wire 6 in which the hollow coil 60 covers the entire core shaft 610, the bending rigidity of the taper portion 62 can be made closer to a linear shape, and the vicinity of the tip end side of the taper portion 62 can be obtained. In, it is possible to make it difficult for a rigidity gap of bending rigidity to occur. Therefore, with the guide wire 6 of the present embodiment, it is possible to suppress the occurrence of kinks when stress is concentrated near the tapered portion 62 of the hollow coil 60 when the guide wire 6 is inserted into a human blood vessel or digestive organ.

<Seventh Embodiment>
FIG. 19: is explanatory drawing which illustrated the partial structure of the hollow coil 7 of 7th Embodiment. In FIG. 19, a part of the hollow coil 7 including the small diameter portion 71, the tapered portion 72, and the large diameter portion 73 is enlarged and displayed. The hollow coil 7 of the seventh embodiment is different from the hollow coil 1 of the first embodiment (FIG. 1) in the shape of the tapered portion. In the tapered portion 72 of the seventh embodiment, the coil outer shape does not decrease in a curved shape (parabolic shape) from the base end side (the large diameter portion 73 side) toward the tip end side (the small diameter portion 71 side), and the inclination It is reduced to two types of different straight lines.

Here, the taper portion 72 is divided into two at equal intervals along the axial direction of the hollow coil 7, and is referred to as “first section N1” and “second section N2” in order from the proximal end side to the distal end side. . The decrease amount of the coil outer diameter in the first section N1 (between the P0 point and the P1 point) is A11, and the decrease amount of the coil outer diameter in the second section N2 (between the P1 point and the P2 point) is A21. To do. FIG. 19 shows an imaginary line IML connecting the upper ends of the coil outer diameter at points P0 to P2.

At this time, the tapered portion 72 of the hollow coil 7 of the present embodiment is configured such that the reduction amount A11 to A12 of the coil outer diameter is A11> A12. That is, the coil outer diameter is formed so that the degree of decrease in the coil outer diameter decreases from the side having a relatively large coil outer diameter (base end side) to the side having a relatively small coil outer diameter (tip end side).

According to the present embodiment described above, the tapered outer shape of the tapered portion 72 does not decrease in a curved shape from the base end side (the large diameter portion 73 side) toward the tip end side (the small diameter portion 71 side). On the other hand, in the hollow coil 7 as well, the taper portion 72 has a smaller degree of decrease in coil outer diameter from the base end side where the coil outer diameter is relatively large toward the tip end side where the coil outer diameter is relatively smaller. As a result, the bending rigidity of the taper portion 72 can be approximated to a linear shape, and a rigidity gap of the bending rigidity can be less likely to occur near the tip side of the taper portion 72. Therefore, in the medical device using the hollow coil 7 of the present embodiment, when it is inserted into a blood vessel or digestive organ of a human body, stress is less likely to be concentrated in the vicinity of the taper portion 72 of the hollow coil 7, and a kink is not generated. Can be suppressed.

As described above, in the tapered portion of the present embodiment, the change in the coil outer diameter does not have to be a curved shape. The tapered portion is divided into two or more at equal intervals along the axial direction of the hollow coil to set a plurality of sections, and the degree of decrease in the coil outer diameter of each section is from the side where the coil outer diameter is relatively large to the outside of the coil. If the diameter decreases toward the relatively smaller side, it corresponds to the tapered portion of the present embodiment. Here, an example in which the tapered portion is divided into two sections is shown, but the number of divisions may be any number of 2 or more.

<Eighth Embodiment>
FIG. 20 is an explanatory diagram illustrating the partial configuration of the hollow coil 8 of the eighth embodiment. In FIG. 20, a part of the hollow coil 8 including the small diameter portion 81, the tapered portion 82, and the large diameter portion 83 is enlarged and displayed. The hollow coil 8 of the eighth embodiment is different from the hollow coil 1 of the first embodiment (FIG. 1) in the shape of the tapered portion. In the tapered portion 82 of the eighth embodiment, the coil outer shape does not decrease in a curved shape (parabolic shape) from the base end side (the large diameter portion 83 side) to the tip end side (the small diameter portion 81 side), and the taper gradually increases. Is decreasing.

Here, the taper portion 82 is divided into four at equal intervals along the axial direction of the hollow coil 8, and the “first section N1”, the “second section N2”, and the “second section N2” are sequentially arranged from the base end side toward the tip end side. These are referred to as the “third section N3” and the “fourth section N4”. The decrease amount of the coil outer diameter in the first section N1 (between the P0 point and the P1 point) is A21, and the decrease amount of the coil outer diameter in the second section N2 (between the P1 point and the P2 point) is A22. The decrease amount of the coil outer diameter in the third section N3 (between the point P2 and the point P3) is A23, and the decrease amount of the coil outer diameter in the fourth section N4 (between the point P3 and the point P4) is A24. FIG. 20 shows a virtual line IML connecting the upper ends of the coil outer diameter at points P0 to P4.

At this time, the tapered portion 82 of the hollow coil 8 of the present embodiment is configured such that the reduction amount A21 to A24 of the coil outer diameter is A21> A22> A23> A24. That is, the coil outer diameter is formed so that the degree of decrease in the coil outer diameter decreases from the side having a relatively large coil outer diameter (base end side) to the side having a relatively small coil outer diameter (tip end side).

According to the present embodiment described above, the tapered outer shape of the tapered portion 82 does not decrease in a curved shape from the base end side (the large diameter portion 83 side) to the tip end side (the small diameter portion 81 side). On the other hand, also in the hollow coil 8, the taper portion 82 has a smaller degree of decrease in the coil outer diameter from the base end side where the coil outer diameter is relatively large to the tip end side where the coil outer diameter is relatively smaller. As a result, the bending rigidity of the taper portion 82 can be approximated to a linear shape, and a rigidity gap of bending rigidity can be less likely to occur near the tip end side of the taper portion 82. Therefore, in the medical device using the hollow coil 8 of the present embodiment, when it is inserted into a blood vessel or a digestive organ of a human body, stress is less likely to be concentrated in the vicinity of the tapered portion 82 of the hollow coil 7, and a kink is not generated. Can be suppressed.

<Modification of this embodiment>
The present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the scope of the invention, and the following modifications are possible, for example.

[Modification 1]
The hollow coil 1 of the first embodiment has been described as the one in which the bending rigidity of the tapered portion 12 linearly changes from one end side toward the other end side (FIG. 9). However, the bending rigidity of the tapered portion 12 does not necessarily have to linearly change from the one end side toward the other end side. That is, if the taper portion 12 is formed so that the degree of decrease in the coil outer diameter decreases from the base end side toward the tip end side, the bending rigidity can be made to be linear, and the bending rigidity can be made to be linear. If it is possible to prevent the occurrence of a rigid gap. However, it is more preferable that the tapered portion 12 has a shape so that the bending rigidity linearly changes, because the rigidity gap can be further suppressed.

[Modification 2]
In the first embodiment, the taper portion 12 has been described as being formed so that the degree of decrease in the coil outer diameter inevitably decreases in order from the base end side to the tip end side. However, it suffices that the tapered portion 12 be formed so that the degree of decrease in the coil outer diameter decreases in order from the base end side to the tip end side, and the coil outer diameter decreases from the base end side to the tip end side. It may have a portion whose degree is not reduced.

[Modification 3]
In the first embodiment, it has been described that the coil outer diameters of the small diameter portion 11 and the large diameter portion 13 are constant. However, the coil outer diameters of the small diameter portion 11 and the large diameter portion 13 are not constant, and the coil outer diameter may partially change. Further, the small-diameter portion 11 does not need to have the smallest coil outer diameter in the hollow coil 1. The large-diameter portion 13 may not have the maximum coil outer diameter in the hollow coil 1. Further, the hollow coil 1 may not include at least one of the small diameter portion 11 and the large diameter portion 13.

[Modification 4]
In the first embodiment, the small diameter portion 11, the tapered portion 12, and the large diameter portion 13 each have a constant wire diameter, and the wire diameters are equal to each other. However, the wire diameters of the tapered portion 12 and the large-diameter portion 13 do not have to be constant, and their linear shapes may be different from each other. That is, the diameter of the strand 15 may partially change. Further, the wire 15 may be hollow or may have a cross-sectional shape other than circular.

[Modification 5]
In the first embodiment, the taper portion 12 is formed so that the coil pitch increases from the base end side toward the tip end side. However, the coil pitch of the tapered portion 12 may be constant throughout. Further, the coil pitch of the tapered portion 12 may be equal to the coil pitch of the small diameter portion 11 or the large diameter portion 13. The coil pitch of the large diameter portion 13 is smaller than the coil pitch of the small diameter portion 11. However, the coil pitch of the large diameter portion 13 may be equal to the coil pitch of the small diameter portion 11. With such a configuration, it is possible to suppress the occurrence of the rigid gap due to the change in the coil pitch. Specifically, as shown in the above formula (4), the bending rigidity EI of the tapered portion 12 is proportional to the coil pitch. Therefore, if the coil pitch of the taper portion 12 changes, the bending rigidity of the taper portion 12 also changes, and a rigidity gap is likely to occur. Therefore, according to this configuration, it is possible to further suppress changes in bending rigidity due to factors other than changes in the coil outer diameter.

[Modification 6]
The hollow coil 1 of the first embodiment has been described as being formed by 10 strands. However, the hollow coil 1 may be a hollow stranded wire coil in which 2 to 9 strands or more than 10 strands are twisted together, and one strand may be spirally wound into a cylindrical shape. It may be a single coil formed in a shape.

[Modification 7]
The strand 15 of the first embodiment may be made of a metal other than a stainless alloy. For example, the wire 15 includes, for example, a superelastic alloy such as a nickel-titanium alloy, a piano wire, a nickel-chromium alloy, a cobalt alloy, a radiation transmissive alloy such as tungsten, gold, platinum, tungsten, and these elements. It can be formed of a radiopaque alloy such as an alloy (eg, platinum-nickel alloy). Further, the wire 15 may be formed of a known material other than the above.

[Modification 8]
In the dilators of the second to third embodiments, the taper portion is formed so that the coil outer shape becomes smaller from the base end side to the tip end side of the dilator. However, the tapered portion may be formed in a direction in which the outer shape of the coil decreases from the tip end side of the dilator to the base end side. Similarly, in the guide wires of the fourth to sixth embodiments, the tapered portion may be formed in such a direction that the outer shape of the coil becomes smaller from the distal end side to the proximal end side of the guide wire.

The present aspect has been described above based on the embodiment and the modification, but the embodiment of the aspect described above is intended to facilitate understanding of the present aspect, and does not limit the present aspect. The present embodiment can be modified and improved without departing from the spirit and scope of the claims, and the present embodiment includes equivalents thereof. If the technical features are not described as essential in this specification, they can be deleted as appropriate.

1, 7, 8, 20, 30, 40, 50, 60 ... Hollow coil 2, 3 ... Dilator 4, 5, 6 ... Guide wire 11, 21, 41, 61, 71, 81 ... Thin portion 12, 22, 32, 42, 52, 62, 72, 82 ... Tapered portion 13, 23, 33, 43, 63, 73, 83 ... Large diameter portion 15, 25, 35 ... Element wire 16 ... Lumen 17, 27, 317, ... Tip- side opening 19, 209, 309 ... Base- end side opening 200, 300 ... Connector 310 ... Tip member 410, 510, 610 ... Core shaft 421, 521, 621 ... Tip-joining portion 425, 525, 625 ... Base-joining Department

Claims (6)

1. A hollow coil,
   The hollow coil has a taper portion whose outer diameter decreases from one end side toward the other end side,
   The hollow coil is characterized in that the taper portion is formed such that the degree of decrease in the coil outer diameter decreases from the one end side toward the other end side.
2. The hollow coil according to claim 1,
   The degree of decrease of the outer diameter of the coil in the tapered portion is set so that the bending rigidity linearly changes in at least a part of the tapered portion.
3. The hollow coil according to claim 1 or 2, further comprises:
   A hollow coil having a constant diameter portion having a constant coil outer diameter between the tapered portion and the one end of the hollow coil.
4. The hollow coil according to any one of claims 1 to 3,
   A hollow coil, wherein the tapered portion is formed of a wire having a constant outer diameter.
5. A hollow coil according to any one of claims 1 to 4,
   A connector connected to the base end of the hollow coil.
6. A hollow coil according to any one of claims 1 to 4,
   A core shaft at least a part of which is arranged inside the hollow coil;
   A tip joining portion where the tip of the core shaft and the tip of the hollow coil are joined;
   A guide wire, comprising: the core shaft; and a proximal end joint portion to which a proximal end of the hollow coil is joined.

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