Patent Description:
In medical treatment such as endoscope inspection, a medical device used by being inserted to a body cavity is used. Patent Literature <NUM> discloses a medical device formed of a hollow twisted wire. This hollow twisted wire includes a first layer and a second layer and is configured such that a twisting direction of a wire in the first layer and a twisting direction of a wire in the second layer are opposite to each other.

[Patent Literature <NUM>] <CIT>; <CIT>; <CIT>.

A dilator that expands a hole formed in a wall of the alimentary canal or the like of a patient for treatment is known. A hole is expanded by inserting a distal end of the dilator to the hole formed in a wall and pushing a tapered portion to the hole. In a case where the hollow twisted wire including two layers disclosed in Patent Literature <NUM> is applied to a dilator, an inner layer contracts and an outer layer expands depending on a rotation direction of the dilator, so that the two layers do not contact with each other and sufficient torquability may not be obtained.

The present disclosure has an object to provide a dilator capable of obtaining high torquability irrespective of a rotation direction.

In order to achieve such an object, a dilator according to an aspect of the present disclosure includes: a distal end side coil part; and a proximal end side coil part located at a proximal end side of the distal end side coil part and having a distal end portion connected to a proximal end portion of the distal end side coil part, the distal end side coil part including a first coil formed by winding a wire in a first winding direction to have a hollow shape, and a second coil provided on an outer periphery of the first coil and formed by winding a wire in a second winding direction being an opposite winding direction to the first winding direction, the proximal end side coil part including a third coil formed by winding a wire in the second winding direction to have a hollow shape, and a fourth coil provided on an outer periphery of the third coil and formed by winding a wire in the first winding direction.

The first winding direction may be a direction of S-winding, and the second winding direction may be a direction of Z-winding.

A diameter of the wire of the third coil may be smaller than a diameter of the wire of the fourth coil.

An entire periphery of the proximal end portion of the distal end side coil part and an entire periphery of the distal end portion of the proximal end side coil part may be welded to each other.

The first coil and the third coil may be formed of different wires from each other, and the second coil and the fourth coil may be formed of different wires from each other.

The invention is defined in claim <NUM>; multiple embodiments are defined in the dependent claims.

According to the present disclosure, it is possible to provide a dilator capable of obtaining high torquability irrespective of a rotation direction.

The size of the dilator in each drawing is a size illustrated to facilitate understanding of the embodiments, and does not correspond to the actual size.

In this specification, the "distal end side" indicates a direction along the longitudinal direction of the dilator (a direction along an axial direction of the dilator), the direction being a direction in which a distal end side coil part is located with respect to a proximal end side coil part. The "proximal end side" indicates a direction along the longitudinal direction of the dilator, the direction being a direction opposite to the distal end side. Moreover, the "distal end" indicates an end part on the distal end side of an arbitrary member or portion, and the "proximal end" indicates an end part on the proximal end side of an arbitrary member or portion.

<FIG> is an overall configuration diagram of a dilator <NUM> according to an embodiment of the present disclosure. In <FIG>, the left side in the drawing is the distal end side (far side) inserted into a body, and the right side in the drawing is the proximal end side (hand side, near side) operated by a technician such as a doctor. <FIG> is a cross-sectional view of the dilator <NUM> of <FIG> cut in line IIA-IIA, <FIG> is a cross-sectional view of the dilator <NUM> of <FIG> cut in line IIB-IIB, and <FIG> is a cross-sectional view of the dilator <NUM> of <FIG> cut in line IIC-IIC.

The dilator <NUM> includes a distal end side coil part <NUM>, a proximal end side coil part <NUM>, and a connector <NUM>.

The distal end side coil part <NUM> is located at the most distal end side in the axial direction of the dilator <NUM>, and includes a first coil <NUM> and a second coil <NUM>. The second coil <NUM> is wound around an outer peripheral surface of the first coil <NUM>. The wire forming the first coil <NUM> and the second coil <NUM> is, for example, a metal wire of a superelastic alloy or the like such as a stainless steel and a nickel-titanium, or a resin wire.

As illustrated in <FIG>, and <FIG>, the first coil <NUM> is formed by winding a plurality of (for example, <NUM>) wires to have a hollow shape. The plurality of wires forming the first coil <NUM> are wound in a first winding direction. The first coil <NUM> has a lumen 11a penetrating from the proximal end to the distal end. The first coil <NUM> has a straight portion 11B and a tapered portion 11C.

The straight portion 11B is located at the proximal end side of the first coil <NUM>, and has a proximal end connected to the proximal end side coil part <NUM>. The straight portion 11B has an outer diameter that is substantially constant from a proximal end to a distal end of the straight portion 11B. The tapered portion 11C is located at the distal end side of the straight portion 11B, extends from the distal end of the straight portion 11B to the distal end side, and is configured such that an outer diameter thereof becomes small toward the distal end side.

The second coil <NUM> is formed by winding, for example, one wire around an outer peripheral surface 11D of the first coil <NUM> in a second winding direction opposite to the first winding direction. In the present embodiment, the first winding direction is a direction of S-winding, and the second winding direction is a direction of Z-winding. The wire forming the second coil <NUM> is wound with a space. As a result, the outer peripheral surface 11D of the first coil <NUM> is provided with a spirally-arranged protruding portion projecting to the outside (the most outer surface, the most outside portion of the dilator <NUM>). This spirally-arranged protruding portion has a gap in portions adjacent to each other (metal wires adjacent to each other) along the axis of the first coil <NUM>. Due to a screw action of the spirally-arranged protruding portion, the dilator <NUM> can move forward also by rotation operation of the dilator <NUM>.

As illustrated in <FIG>, the proximal end side coil part <NUM> is located at the proximal end side of the distal end side coil part <NUM>, and includes a third coil <NUM> and a fourth coil <NUM>. The fourth coil <NUM> is wound around an outer peripheral surface of the third coil <NUM>. The proximal end of the proximal end side coil part <NUM> is connected with the connector <NUM>. The wire forming the third coil <NUM> and the fourth coil <NUM> is, for example, a metal wire of a superelastic alloy such as a stainless steel and a nickel-titanium, or a resin wire.

As illustrated in <FIG> and <FIG>, the third coil <NUM> is formed by winding a plurality of (for example, <NUM>) metal wires to have a hollow shape. The plurality of wires forming the third coil <NUM> are wound in the second winding direction. The third coil <NUM> has a lumen 21a penetrating from a proximal end to a distal end, and has an outer diameter that is substantially constant from the proximal end to the distal end. The lumen 11a of the first coil <NUM> and the lumen 21a of the third coil <NUM> communicate with each other.

The fourth coil <NUM> is formed by winding a plurality of (for example, <NUM>) wires around an outer peripheral surface 21B of the third coil <NUM> in the first winding direction. The diameter of the wire forming the fourth coil <NUM> is larger than the diameter of the wire forming the third coil. The outer diameter of the fourth coil <NUM> is almost equal to or slightly larger than the outer diameter of the second coil <NUM>.

A plurality of wires forming the distal end portions and the proximal end portions of the first coil <NUM>, the third coil <NUM>, and the fourth coil <NUM> are welded over the entire peripheral direction of the first coil <NUM>, the third coil <NUM>, and the fourth coil <NUM> so as not to separate from each other. The second coil <NUM> is welded to the first coil <NUM> in the distal end and the proximal end of the second coil <NUM>, for example. The first coil <NUM> and the third coil <NUM> are formed of different wires from each other, and the second coil <NUM> and the fourth coil <NUM> are formed of different wires from each other.

The entire periphery of the proximal end portion 10A of the distal end side coil part <NUM> and the entire periphery of the distal end portion 20A of the proximal end side coil part <NUM> are welded to each other. As a result, a welded portion <NUM> is formed in a connection portion between the distal end side coil part <NUM> and the distal end side coil part <NUM>. The welded portion <NUM> has a tapered shape such that it tapers to the distal end side.

A length of the dilator <NUM> in the present embodiment and other embodiments described hereinafter is, for example, <NUM>, and may be <NUM> to <NUM>. A length of the distal end side coil part <NUM> is, for example, <NUM>, and may be <NUM> to <NUM>. A length of the proximal end side coil part <NUM> is, for example, <NUM>, and may be <NUM> to <NUM>. An inner diameter of the distal end of the first coil <NUM> is, for example, <NUM>, and may be <NUM> to <NUM>. An inner diameter of the proximal end of the first coil <NUM> and an inner diameter of the distal end of the third coil <NUM> are for example, <NUM>, and may be <NUM> to <NUM>. An outer diameter of the distal end of the second coil <NUM> is, for example, <NUM>, and may be <NUM> to <NUM>. An outer diameter of the proximal end of the second coil <NUM> is, for example, <NUM>, and may be <NUM> to <NUM>. A diameter of the metal wire of the first coil <NUM> and a diameter of the metal wire of the third coil <NUM> are for example, <NUM>, and may be <NUM> to <NUM>. A diameter of the metal wire of the second coil <NUM> and a diameter of the metal wire of the fourth coil <NUM> are for example, <NUM>, and may be <NUM> to <NUM>.

The connector <NUM> is a portion used by a technician for rotation operation such as pushing the dilator <NUM> into a body or pulling the dilator <NUM> from the body. The distal end of the connector <NUM> is connected to the proximal end of the proximal end side coil part <NUM>. The connector <NUM> is formed of, for example, a resin, and has a hollow shape having a lumen that communicates with the lumen 21a of the third coil <NUM>.

Next, an example of the use mode of the dilator <NUM> is described as follows.

First, an object is punctured with an introducer needle to form a hole. Next, after insertion of a guide wire into a lumen of the introducer needle, the introducer needle is pulled out.

Next, a proximal end of the guide wire is inserted to the inner cavity of the dilator <NUM> to insert the dilator <NUM>. Next, the dilator <NUM> is pushed to advance while rotating a shaft (distal end side coil part <NUM> and the proximal end side coil part <NUM>) in the clockwise direction, to expand the hole of the punctured portion. At this time, since the tapered portion 11C moves forward due to a screw action or the like of the spirally-arranged protruding portion caused by the rotation operation of the shaft, the hole can be smoothly expanded by the tapered portion 11C. In order to move the dilator <NUM> rearward, the shaft is rotated in the counterclockwise direction.

In the dilator <NUM> of the present embodiment, the distal end side coil part <NUM> includes the first coil <NUM> formed by winding a wire in the first winding direction to have a hollow shape, and the second coil <NUM> provided on an outer periphery of the first coil <NUM> and formed by winding a wire in the second winding direction being an opposite winding direction to the first winding direction, and the proximal end side coil part <NUM> includes the third coil <NUM> formed by winding a wire in the second winding direction to have a hollow shape, and the fourth coil <NUM> provided on an outer periphery of the third coil <NUM> and formed by winding a wire in the first winding direction. The first winding direction is a direction of S-winding, and the second winding direction is a direction of Z-winding.

According to this configuration, when the dilator <NUM> is rotated in a direction of moving forward (clockwise: R direction in the drawing) due to a screw action of the first coil <NUM>, in the distal end side coil part <NUM>, a pitch of the first coil <NUM> decreases and the outer diameter of the first coil <NUM> decreases. In addition, a pitch of the second coil <NUM> increases and the outer diameter of the second coil <NUM> increases. As a result, when the dilator <NUM> is caused to advance in a constricted part while rotating in the clockwise direction, the second coil <NUM> expands in the radial direction and pushes and widens the constricted part, so that a performance of the dilator <NUM> of expanding the constricted part can be enhanced. On the contrary, in the proximal end side coil part <NUM>, a pitch of the third coil <NUM> increases and the outer diameter of the third coil <NUM> increases. In addition, a pitch of the fourth coil <NUM> decreases and the inner diameter of the fourth coil <NUM> decreases. As a result, a force of the third coil <NUM> expanding in the radial direction and a force of the fourth coil <NUM> contracting in the radial direction interact with each other, and the wire of the third coil <NUM> and the wire of the fourth coil <NUM> closely contact with each other. Accordingly, torquability in the proximal end side coil part <NUM> can be enhanced. As described above, when the dilator <NUM> is rotated in the clockwise direction, by pushing and widening the constricted part in the radial direction by the distal end portion of the dilator <NUM>, the expansion force for the constricted part can be increased, and entirely relatively high torquability can be obtained.

On the contrary, when the dilator <NUM> is rotated in a direction of moving rearward (counterclockwise direction), in the proximal end side coil <NUM>, a pitch of the third coil <NUM> decreases and the outer diameter of the third coil <NUM> decreases. In addition, a pitch of the fourth coil <NUM> increases and the outer diameter of the fourth coil <NUM> increases. On the contrary, in the distal end side coil part <NUM>, a pitch of the first coil <NUM> increases and the outer diameter of the first coil <NUM> increases. In addition, a pitch of the second coil <NUM> decreases and the inner diameter of the second coil <NUM> decreases. As a result, a force of the first coil <NUM> expanding in the radial direction and a force of the second coil <NUM> contracting in the radial direction interact with each other, and the wire of the first coil <NUM> and the wire of the second coil <NUM> closely contact with each other. Accordingly, torquability in the distal end side coil part <NUM> can be enhanced, and in addition, by increasing the rigidity of the distal end side coil part <NUM>, the performance of the dilator <NUM> of expanding the constricted part can be enhanced. As described above, when the dilator <NUM> is rotated in the counterclockwise direction, by increasing the rigidity of the distal end side, the performance of expanding the constricted part can be enhanced, and entirely relatively high torquability can be obtained.

As described above, according to the dilator <NUM> of the present embodiment, the performance of expanding the constricted part can be enhanced irrespective of the rotation direction of the dilator <NUM>, and relatively high torquability can be obtained. The first winding direction is a direction of S-winding and the second winding direction is a direction of Z-winding, so that high torquability can be obtained in a normal use mode of the dilator <NUM>.

The diameter of the wire forming the fourth coil <NUM> is larger than the diameter of the wire forming the third coil. As a result, the torque force of the proximal end side coil part <NUM> can be increased, and further, the torque force of the dilator <NUM> can be increased.

The entire periphery of the proximal end portion 10A of the distal end side coil part <NUM> and the entire periphery of the distal end portion 20A of the proximal end side coil part <NUM> are welded to each other. As a result, the force applied to the connector <NUM> of the dilator <NUM> can be reliably transmitted to the distal end side coil part <NUM>.

The first coil <NUM> and the third coil <NUM> are formed of different wires from each other, and the second coil <NUM> and the fourth coil <NUM> are formed of different wires from each other. As a result, the distal end side coil part <NUM> and the proximal end side coil part <NUM> are separately formed and connected to each other, so that the dilator <NUM> can be easily manufactured.

Embodiments of the present disclosure has been described above. The present disclosure is not limited to these embodiments, and various modifications may be performed.

For example, as a dilator <NUM> illustrated in <FIG>, the wire forming the fourth coil <NUM> may be wound such that the wire is not in close contact so as to have a space in the distal end side, the spacing amount is gradually reduced toward the proximal end side, and the wire is in close contact in the proximal end side. As a result, the rigidity of the dilator <NUM> can be gradually changed from the proximal end to the distal end. The welded portion <NUM> may not have a tapered shape, and may be configured such that the outer peripheral surface of the welded portion <NUM> is substantially parallel in the axial direction.

The first coil <NUM> and the third coil <NUM> are formed of different wires from each other and the second coil <NUM> and the fourth coil <NUM> are formed of different wires from each other. However, the third coil <NUM> and the first coil <NUM> may be formed of the same wire and the fourth coil <NUM> and the second coil <NUM> may be formed of the same wire.

The diameter of the metal wire forming the fourth coil <NUM> is larger than the diameter of the metal wire forming the third coil. However, the diameter of the metal wire forming the fourth coil <NUM> may be equal to or smaller than the diameter of the metal wire forming the third coil.

The entire periphery of the proximal end portion 10A of the distal end side coil part <NUM> and the entire periphery of the distal end portion 20A of the proximal end side coil part <NUM> are welded to each other. However, the welding may be performed only at some positions (for example, four positions) in the outer periphery.

The distal end side coil part <NUM> includes the straight portion 11B and the tapered portion 11C. However, the distal end side coil part <NUM> may not include the straight portion 11B. In addition, the distal end side coil part <NUM> may include a distal end portion in the distal end side of the tapered portion 11C, the distal end portion having an outer diameter that is substantially constant from the proximal end to the distal end.

The first coil <NUM> and the fourth coil <NUM> are wound in the first winding direction (S-winding) and the second coil <NUM> and the third coil <NUM> are wound in the second winding direction (Z-winding). However, the first coil <NUM> and the fourth coil <NUM> may be wound in the second winding direction (Z-winding) and the second coil <NUM> and the third coil <NUM> may be wound in the first winding direction (S-winding).

According to this configuration, when the dilator <NUM> is rotated in a direction of moving forward (counterclockwise direction) due to a screw action of the first coil <NUM>, in the distal end side coil part <NUM>, a pitch of the first coil <NUM> decreases and the outer diameter of the first coil <NUM> decreases. In addition, a pitch of the second coil <NUM> increases and the outer diameter of the second coil <NUM> increases. As a result, when the dilator <NUM> is caused to advance in a constricted part while rotating in the counterclockwise direction, the second coil <NUM> expands in the radial direction and pushes and widens the constricted part, so that a performance of the dilator <NUM> of expanding the constricted part can be enhanced. On the contrary, in the proximal end side coil part <NUM>, a pitch of the third coil <NUM> increases and the outer diameter of the third coil <NUM> increases. In addition, a pitch of the fourth coil <NUM> decreases and the inner diameter of the fourth coil <NUM> decreases. As a result, a force of the third coil <NUM> expanding in the radial direction and a force of the fourth coil <NUM> contracting in the radial direction act to each other, and the wire of the third coil <NUM> and the wire of the fourth coil <NUM> closely contact with each other. Accordingly, torquability in the proximal end side coil part <NUM> can be enhanced. As described above, when the dilator <NUM> is rotated in the counterclockwise direction, by pushing and widening the constricted part in the radial direction by the distal end portion of the dilator <NUM>, the expansion force in the constricted part can be increased, and entirely relatively high torquability can be obtained.

On the contrary, when the dilator <NUM> is rotated in a direction of moving rearward (clockwise direction), in the proximal end side coil <NUM>, a pitch of the third coil <NUM> decreases and the outer diameter of the third coil <NUM> decreases. In addition, a pitch of the fourth coil <NUM> increases and the outer diameter of the fourth coil <NUM> increases. On the contrary, in the distal end side coil part <NUM>, a pitch of the first coil <NUM> increases and the outer diameter of the first coil <NUM> increases. In addition, a pitch of the second coil <NUM> decreases and the inner diameter of the second coil <NUM> decreases. As a result, a force of the first coil <NUM> expanding in the radial direction and a force of the second coil <NUM> contracting in the radial direction interact with each other, and the wire of the first coil <NUM> and the wire of the second coil <NUM> closely contact with each other. Accordingly, torquability in the distal end side coil part <NUM> can be enhanced, and in addition, by increasing the rigidity of the distal end side coil part <NUM>, the performance of the dilator <NUM> of expanding the constricted part can be enhanced. As described above, when the dilator <NUM> is rotated in the clockwise direction, by increasing the rigidity of the distal end side, the performance of expanding the constricted part can be enhanced, and entirely relatively high torquability can be obtained.

Claim 1:
A dilator comprising:
a distal end side coil part (<NUM>); and
a proximal end side coil part (<NUM>) located at a proximal end side of the distal end side coil part (<NUM>) and having a distal end portion (20A) connected to a proximal end portion (10A) of the distal end side coil part (<NUM>);
wherein the distal end side coil part (<NUM>) includes:
a first coil (<NUM>) formed by winding a wire in a first winding direction to have a hollow shape, and
a second coil (<NUM>) provided on an outer periphery of the first coil and formed by winding a wire in a second winding direction being an opposite winding direction to the first winding direction, and
the proximal end side coil part (<NUM>) includes:
a third coil (<NUM>) formed by winding a wire in the second winding direction to have a hollow shape, and
a fourth coil (<NUM>) provided on an outer periphery of the third coil and formed by winding a wire in the first winding direction.