JP2021191355A - catheter - Google Patents

Abstract

To provide a catheter in which flexing resistance does not change according to a flexing direction even in a catheter provided with a reinforcement body.SOLUTION: A catheter A includes: an outer tube 10; an inner tube 15 inserted in the outer tube 10; and a member 20 housed between them. The reinforcement member 20 is three or more wires 21 arranged in parallel to an axis line P of the inner tube 15. The wires 21 are arranged annually around the axis line P of the inner tube 15 on a cross-section of the catheter A. Centers of the two adjacent wires 21 along a circumferential direction of the catheter A and an angle of the axis line P are almost the same.SELECTED DRAWING: Figure 2

Description

The present invention relates to a catheter.

Treatment using a catheter is widely used for treating a narrowed part of a blood vessel. In order for the catheter to reach the stenosis in the blood vessel, it is necessary to efficiently transmit the pushing force of the technician from the hand of the catheter to the tip of the catheter. As a method thereof, Patent Document 1 describes that a metal core wire (reinforcing body) is arranged in the longitudinal direction between the outer tube and the inner tube of the catheter.

International Publication No. 2006/126642

In Patent Document 1, one reinforcing body is arranged in the outer tube so as to be parallel to the inner tube in the longitudinal direction. The catheter is difficult to bend in the cross section toward the side with the reinforcing body, and easily bends in the direction with the inner tube, that is, the direction without the reinforcing body. There is a concern that the bending resistance will change depending on the bending direction of the catheter, which will interfere with the operator's procedure.

The present invention has been completed based on the above circumstances, and an object of the present invention is to provide a catheter in which bending resistance does not change depending on the bending direction even if the catheter is provided with a reinforcing body.

One aspect of the present invention is as follows.
(1) A catheter, an outer tube having a substantially circular cross section, an inner tube inserted into the outer tube and having a substantially circular cross section, and accommodated between the outer tube and the inner tube. The reinforcing member includes, and the reinforcing member is three or more wires arranged in parallel with the axis of the inner tube, and in the cross section of the catheter, the three or more wires are the inner tube. A catheter that is arranged in a ring shape around the axis of the catheter and has substantially the same angle formed by connecting the center of two adjacent wires along the circumferential direction of the catheter and the axis.
(2) The catheter according to (1), wherein the wire rod is fixed to the outer peripheral surface of the inner tube and / or the inner peripheral surface of the outer tube.
(3) A catheter, an outer tube having a substantially circular cross section, an inner tube inserted into the outer tube and having a substantially circular cross section, and accommodated between the outer tube and the inner tube. A catheter comprising a reinforcing member provided with the reinforcing member, wherein the reinforcing member is a wire rod spirally surrounding the inner tube.
(4) The catheter according to (3), wherein the spiral pitch of the wire rod is larger on the distal end side than on the proximal end side.
(5) The catheter according to any one of (1) to (4), wherein the reinforcing member has a flexural rigidity lower at the distal end than on the proximal end side.
(6) The inner tube has an inner layer made of synthetic resin and a metal outer layer fixed to the outer peripheral surface of the inner layer, and the reinforcing member is arranged along the outer periphery of the outer layer. The catheter according to any one of (1) to (5).

Side sectional view of the catheter of the first embodiment XX-ray cross-sectional view of FIG. XX-ray equivalent cross-sectional view of a catheter as a modification of the first embodiment of FIG. XX-ray equivalent cross-sectional view of a catheter that is a modified example different from FIG. Side sectional view of the catheter of the second embodiment YY line sectional view of FIG. Side sectional view of a catheter as a modification of the second embodiment of FIG.

The catheter according to the embodiment of the present invention includes an outer tube, an inner tube inserted in the outer tube, and a reinforcing member accommodated between them, and holds the inner tube concentrically with the outer tube. Reinforcing members are arranged so as to. Hereinafter, examples of embodiments of the present invention will be described with reference to the drawings. In the description described later, the anterior end and the distal end are used synonymously, and the posterior end and the proximal end are used synonymously.

<Embodiment 1>
First, the first embodiment will be described with reference to FIGS. 1 and 2. The catheter A of the first embodiment includes an outer tube 10, an inner tube 15 coaxially housed inside the outer tube 10, and a reinforcing member 20 housed between the outer tube 10 and the inner tube 15.

The outer tube 10 and the inner tube 15 are long circular tubes made of a flexible synthetic resin, and are deformable so that the axis P thereof can be bent. When the catheter A is in a straight line state, the axes P of the outer tube 10 and the inner tube 15 are aligned with each other.

As shown in FIG. 2, the inner tube 15 has a two-layer structure in which the inner layer 16 and the outer layer 17 are concentrically united. The inner layer 16 is a long circular tube made of a flexible synthetic resin, and is deformable so that the axis P can be curved.

The outer layer body 17 is a long cylindrical member made of metal. The outer layer body 17 can be deformed so that the axis P can be bent, but the outer layer body 17 has a higher bending rigidity than the outer tube 10 and the inner layer body 16.

The inner peripheral surface of the outer layer 17 is fixed to the outer peripheral surface of the inner layer 16 by welding or the like, so that the inner layer 16 and the outer layer 17 can move integrally. At least a part of the outer layer body 17 (inner tube 15) is connected to the inner peripheral surface of the outer tube 10 by a reinforcing body 21 or a connecting member (not shown). As shown in FIG. 1, a connector 11 is attached to the proximal end of the outer tube 10. By operating the connector 11, the outer tube 10 can be rotated, and the inner tube 15 can be rotated by the rotational force.

The reinforcing member 20 has four wire rods 21, and the wire rod 21 extends from the rear end to the front end of the catheter A. The four wire rods 21 are metal members having the same material, outer diameter, length, and shape. In the present embodiment, the outer diameter of the wire rod 21 is ½ of the dimensional difference between the inner diameter of the outer tube 10 and the outer diameter of the inner tube 15.

The four wire rods 21 are arranged in parallel with the axis P of the outer tube 10 and the inner tube 15, and are in line contact with the inner peripheral surface of the outer tube 10 and the outer peripheral surface of the inner tube 15. All of the four wire rods 21 are partially or fixed to the outer peripheral surface of the inner tube 15 over the entire length along the direction of the axis P by welding or the like.

The four wires 21 are arranged in parallel with the axis P, and in the cross section of the catheter A, the four wires 21 are arranged in an annular shape with the axis P as the center. Further, the four wire rods 21 are arranged so that the angles of the centers of the two adjacent wire rods 21 and the axis P are the same. That is, as shown in FIG. 2, the angle α formed by the two straight lines 18 and 19 obtained by connecting the centers of the four wire rods 21 and the axis P is 90 °. It can be said that the four wire rods 21 are arranged at positions that are rotationally symmetric with respect to the axis P (center in the cross section). The inner tube 15 is held concentrically with respect to the outer tube 10 by the reinforcing member 20 composed of the four wire rods 21 having this positional relationship.

Next, as shown in FIG. 3 described in Patent Document 1, the catheter is reinforced with one circular cross-section metal wire core wire I and the four circular cross-section wires 21 according to the first embodiment. Explain the difference between the case of reinforcement II and.

In Case I, as shown in the cross section of the catheter, one metal wire core wire exists between the outer tube and the inner tube (corresponding to the outer tube 10 and the inner tube 15 in the present embodiment). .. The bending rigidity of the catheter differs depending on whether the catheter is to be bent to the side where the metal wire core wire is present or to the opposite side. Furthermore, in order to increase the bending rigidity, it is necessary to make the metal wire core wire thicker, but then the difference in bending rigidity becomes larger.

On the other hand, in Case II, the four wire rods 21 are arranged in an annular shape at substantially equal angular intervals in the cross section of Catheter A, so that the bending rigidity generated by the bending direction of Catheter A is higher than that in Case I. The difference can be suppressed. Further, even if the wire rod 21 is made thicker in an attempt to increase the flexural rigidity, the wire rods 21 are arranged in an annular shape at substantially equal angular intervals along the circumferential direction, so that the difference in flexural rigidity does not change significantly, and the flexural rigidity does not change significantly. It is possible to suppress the difference between.

The catheter A includes an outer tube 10 having a substantially circular cross section, an inner tube 15 inserted into the outer tube 10, and a reinforcing member 20 accommodated between them. Further, in the cross section of the catheter A, the four wire rods 21 are arranged in an annular shape about the axis P of the inner tube 15, so that the reinforcing member 20 makes the inner tube 15 concentric with the outer tube 10. keeping. Further, since the angles of the centers of the two adjacent wires 21 adjacent to each other along the circumferential direction of the catheter A and the axis P are substantially the same, the wires 21 are evenly arranged along the circumferential direction, and the catheter It is possible to prevent the bending resistance from changing depending on the bending direction of A. As a result, the catheter A can prevent the procedure from being hindered.

The reinforcing member 20 is composed of four wire rods 21, and a lumen 14 is formed between the outer peripheral surface of the inner tube 15 and the outer tube 10 and the wire rod 21. Through this lumen 14, a therapeutic fluid such as a contrast medium or physiological saline can be sent from the hand side to the tip side of the catheter A.

The inner tube 15 has an inner layer 16 made of synthetic resin and an outer layer 17 made of metal, and has a two-layer structure in which the outer layer 17 is fixed to the outer peripheral surface of the inner layer 16. On the outer circumference of the outer layer 17, four wire rods 21 constituting the reinforcing member 20 are arranged along the outer circumference. With this configuration, the rigidity of the inner tube 15 can be increased.

Next, a modified example of the first embodiment will be described. The first modification will be described with reference to FIG. The shape of the reinforcing member of the catheter B is different from that of the first embodiment. In addition, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In the example shown in FIG. 2, the cross section of the four wires 21 constituting the reinforcing member 20 is circular, whereas in the first modification, as shown in FIG. 3, the cross section of the catheter B is traversed. In terms of the surface, the four wire rods 31 are arranged at a constant pitch in the circumferential direction of the catheter B, and the cross-sectional shape of the wire rod 31 is fan-shaped. Further, the inner peripheral surface 32 of the wire rod 31 has an arc shape having the same curvature as the outer peripheral surface of the inner tube 15, and the outer peripheral surface 33 of the wire rod 31 has an arc shape having the same curvature as the inner peripheral surface of the outer tube 10. Nasu. The inner peripheral surface 32 of the wire rod 31 is fixed to the outer peripheral surface of the inner tube 15 by surface contact or the like, and the outer peripheral surface 33 of the wire rod 31 is also in surface contact with the inner peripheral surface of the outer tube 10. With this configuration, it is easier to transmit the rotational force of the outer tube 10 generated by the operation of the connector 11 to the inner tube 15 than in the example of FIG.

The second modification will be described with reference to FIG. In the examples shown in FIGS. 2 and 3, the reinforcing member is composed of four wires, but in the present invention, the reinforcing member may be composed of three or more wires. Further, it is not necessary to strictly arrange three or more wire rods at equal angle intervals in the circumferential direction, and it is sufficient to arrange them at substantially equal angle intervals. In the second modification, an example in which the reinforcing member is composed of three wires is shown.

The reinforcing member 35 has three wire rods 36, and in the cross section of the catheter C, the wire rods 36 are arranged in an annular shape about the axis P of the inner tube and are adjacent to each other along the circumferential direction of the catheter C. The angles β, γ, and δ formed by the three straight lines 37 obtained by connecting the centers of the two wires and the axis P are the same. In this case, the angles β, γ, and δ are all 120 °. Even in the cross section of the catheter C, since the wire rods 36 are arranged in an annular shape at equal angle intervals, it is possible to suppress the difference in bending rigidity caused by the bending direction of the catheter C.

In the present invention, the angles formed by connecting the centers of two adjacent wires along the circumferential direction of the catheter and the axis of the inner tube do not necessarily have to be the same, but within a range that can be regarded as substantially the same. All you need is. The angles β, γ, and δ may be within a range that can suppress the difference in flexural rigidity caused by the bending direction of the catheter C to some extent. That is, in the present invention, in the cross section of the catheter, three or more wires are positioned at the vertices of a substantially regular n-sided polygon (n is an integer of 3 or more).

In the first embodiment, the wire rod of the reinforcing body is linear along the axial direction of the catheter, but may be in the form of a blade. When the wire rod is in the form of a blade, the wire rod may be arranged in an annular shape about the axis P of the inner tube in the cross section of the catheter.

<Embodiment 2>
The second embodiment will be described with reference to FIGS. 5 and 6. The catheter D of the second embodiment is different from the first embodiment in the form of the reinforcing member. Other configurations are the same as those in the first embodiment, and the same configurations are designated by the same reference numerals and the description thereof will be omitted.

The reinforcing member 22 of the catheter D is composed of one wire rod 23, and as shown in FIG. 5, the wire rod 23 is spirally wound around the entire length along the outer peripheral surface of the inner tube 15. The pitch of the spiral is constant over the entire length of the catheter D.

The wire rod 23 is fixed to the outer peripheral surface of the outer layer 17 of the inner tube 15 by welding or the like. In the axis P direction of the catheter D (inner tube 15), the region where the wire rod 23 is fixed to the outer peripheral surface of the inner tube 15 may extend over the entire length of the inner tube 15, or may be only a part in the axis P direction. good.

Since the reinforcing member 22 is composed of the wire rod 23, a lumen 24 is formed between the outer peripheral surface of the inner tube 15 and the peripheral surface of the wire rod 23. Since the wire rod 23 spirally surrounds the inner tube 15, the lumen 24 is also a spiral space, but like the catheter A, the therapeutic fluid is passed through the lumen 24 to the hand side of the catheter D. It is possible to send from to the tip side. The spirally wound wire 23 surrounds the entire circumference of the inner tube 15, and the bending rigidity of the catheter B does not change significantly regardless of which direction the catheter B is bent. Therefore, it can be said that the operability of the catheter D is good.

Next, a modified example of the second embodiment will be described with reference to FIG. 7. Catheter E has a different reinforcing member from the examples of FIGS. 5 and 6. In addition, the same components as those in the second embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Similar to the reinforcing member 22 of the second embodiment, the reinforcing member 25 is composed of one wire rod 26 spirally wound along the outer peripheral surface of the inner tube 15, but the wire rod 26 is in the axis P direction. The spiral pitch is not constant.

That is, in the region of the total length of the catheter C having a predetermined length on the distal end side, the spiral pitch in the axial P direction of the wire rod 26 gradually increases from the proximal end side to the distal end side. As the spiral pitch increases, the bending rigidity of the reinforcing member 25 decreases, so that the distal end side of the catheter C is easier to bend toward the distal end side. The region of the reinforcing member 25 on the distal end side where the spiral pitch changes is the low-rigidity portion 27. In most of the region of the total length of the catheter C on the proximal end side, the spiral pitch of the wire rod 26 is the same as the outer diameter of the wire rod 26, and the high-rigidity portion 28 formed by winding the wire rod 26 in close contact with the wire rod 26. It has become.

The wire rod 26 is fixed to the outer peripheral surface of the outer layer 17 of the inner tube 15 by means such as welding. The region for fixing the wire rod 26 to the outer peripheral surface of the inner tube 15 in the axis P direction of the catheter C may extend the entire length of the inner tube 15, and only a part in the axis P direction (for example, the height on the proximal end side). It may be only the rigid portion 28).

In the catheter C, the high rigidity of the high-rigidity portion 28 of the reinforcing member 25 facilitates the transmission of the pushing operation force at the proximal end to the entire catheter C. Further, in the low-rigidity portion 27 on the distal end side of the reinforcing member 25, there is an advantage that the tip portion of the catheter C can be easily bent.

Further, as a means for lowering the bending rigidity of the low-rigidity portion 27 to be lower than that of the high-rigidity portion 28, the reinforcing member 25 is configured by the wire rod 26 that spirally surrounds the inner tube 15, and the pitch of the spiral of the wire rod 26 is set to the proximal end. It is made larger on the distal end side (low rigidity portion 27) than on the side (high rigidity portion 28). According to this configuration, the bending rigidity of the distal end portion of the reinforcing member 25 can be made lower than the bending rigidity of the proximal end side of the reinforcing member 25 without changing the wire diameter dimension of the wire rod 26.

The present invention is not limited to the forms described above, and for example, the following forms are also included in the technical scope of the present invention.

The wire rod arranged between the inner tube and the outer tube does not necessarily have the same material, size and shape. For example, the cross-sectional shape of the wire rod is a non-circular shape such as an ellipse, an oval shape, a square shape, or a trapezoidal shape. It may be in the shape of. The reinforcing member may be fixed to the outer tube or may be fixed only to the outer tube.

The inner tube may have a single-layer structure having no metal outer layer, instead of a two-layer structure in which a metal outer layer is in close contact with the outer periphery of the synthetic resin inner layer. The inner layer body and the outer layer body may not be fixed to each other and may be relatively rotatable. The gap between the inner tube and the outer tube may be filled with another member.

In the second embodiment, the reinforcing member is composed of a single-row coil in which one wire is wound, but the reinforcing member may be a multi-row coil in which a plurality of wires are wound.

A catheter (Embodiment 1)
10 Outer tube 11 Connector 15 Inner tube 16 Inner layer 17 Outer layer 18 Straight line 19 Straight line 20 Reinforcing member 21 Wire rod B catheter (first modification of the first embodiment)
30 Reinforcing member 31 Wire rod 32 Inner peripheral surface 33 Outer peripheral surface C catheter (second modification of Embodiment 1)
35 Reinforcing member 36 Wire rod 37 Straight D catheter (Embodiment 2)
22 Reinforcing member 23 Wire rod 24 Lumen E catheter (Modified example of Embodiment 2)
25 Reinforcing member 26 Wire rod 27 Low rigidity part 28 High rigidity part

Claims (6)

It ’s a catheter,
The outer tube, which has a substantially circular cross section,
An inner tube inserted into the outer tube and having a substantially circular cross section,
A reinforcing member accommodated between the outer tube and the inner tube is provided.
The reinforcing member is three or more wires arranged in parallel with the axis of the inner tube.
In the cross section of the catheter, the three or more wires are arranged in an annular shape around the axis of the inner tube, and are formed by connecting the center of two adjacent wires and the axis along the circumferential direction of the catheter. Catheter with approximately the same angle. The catheter according to claim 1, wherein the wire rod is fixed to the outer peripheral surface of the inner tube and / or the inner peripheral surface of the outer tube. It ’s a catheter,
The outer tube, which has a substantially circular cross section,
An inner tube inserted into the outer tube and having a substantially circular cross section,
A reinforcing member accommodated between the outer tube and the inner tube is provided.
The reinforcing member is a catheter that is a wire rod that spirally surrounds the inner tube. The catheter according to claim 3, wherein the spiral pitch of the wire rod is larger on the distal end side than on the proximal end side. The catheter according to any one of claims 1 to 4, wherein the reinforcing member has a flexural rigidity lower at the distal end than on the proximal end side. The inner tube has an inner layer made of synthetic resin and a metal outer layer fixed to the outer peripheral surface of the inner layer.
The catheter according to any one of claims 1 to 5, wherein the reinforcing member is arranged along the outer periphery of the outer layer body.

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