catheter

Abstract

To provide a catheter which includes an operation wire and a sub-lumen and is excellent in operability by the operation wire and durability of the sub-lumen.SOLUTION: A catheter 10 comprises: a tubular body 20 which has a main lumen 21a and a plurality of sub-lumens 25a disposed around the main lumen 21a and extending along a longitudinal direction of the main lumen 21a; and an operation wire 30 which is disposed in the sub-lumen 25a and has a distal end fixed to a distal end of the tubular body 20. The sub-lumen 25a is formed by a resin hollow tube 25 disposed along the main lumen 21a. A cross-sectional shape orthogonal to a longitudinal direction, of the sub-lumen 25a is of a flat annular shape in which dimension of a first direction D1 along a radial direction of the tubular body 20 is shorter than a dimension of a second direction D2 orthogonal to the first direction D1. Thickness t1 of a first portion 26 located in the first direction D1, of the hollow tube 25 is larger than thickness t2 of a second portion 27 located in the second direction D2, of the hollow tube 25.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a catheter.

Background Art

[0002] Conventionally, catheters have been provided that allow the direction of entry into a body cavity to be manipulated by bending the distal end. For example, Patent Document 1 discloses a catheter having a sheath in which sub-lumens are formed in parallel around a main lumen through which a medical solution or the like flows, and an operation wire is inserted through the sub-lumens. In this type of catheter, it is possible to perform an operation to bend the distal end of the sheath by pulling the operation wire on the proximal end side.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0004] In this type of catheter, at the portion where the sub-lumen of the sheath is arranged, the amount of resin in the radial direction of the sheath is smaller than that at portions other than the sub-lumen in the circumferential direction, and the strength of the sheath may decrease. Therefore, in order to suppress a decrease in the amount of resin in the radial direction of the sheath at the portion where the sub-lumen is arranged while ensuring the operability of the operation wire, a flat cross-sectional shape with a relatively short radial opening dimension is sometimes provided for the sub-lumen in the sheath.

[0005] However, when applying the sub-lumen with the above cross-sectional shape, an event in which the tubular body of the sub-lumen breaks at the portion facing the radial direction of the sheath is likely to occur when the sheath bends or when the internal pressure of the main lumen due to the supply of a medical solution or the like is applied to the sub-lumen.

[0006] Therefore, the present invention has been made in view of the above circumstances, and aims to provide a catheter with excellent operability via the operating wire and durability of the sub-lumen. [Means for solving the problem]

[0007] A catheter according to one aspect of the present invention comprises a tubular body having a main lumen, a plurality of sub-lumens arranged around the main lumen and extending along the longitudinal direction of the main lumen, and a control wire disposed within the sub-lumens and having its distal end fixed to the distal end of the tubular body. The sub-lumens are formed from hollow resin tubes arranged along the main lumen, and the cross-sectional shape of the sub-lumens perpendicular to the longitudinal direction is a flattened annular shape in which the dimension in a first direction along the radial direction of the tubular body is shorter than the dimension in a second direction perpendicular to the first direction. The thickness of a first portion located in the first direction of the hollow tube is greater than the thickness of a second portion located in the second direction of the hollow tube. [Effects of the Invention]

[0008] According to one aspect of the present invention, a catheter can be provided that offers excellent operability via the operating wire and durability of the sub-lumen. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side view showing an example of the catheter of this embodiment. [Figure 2] This is a magnified cross-sectional view of the AA line portion of the catheter. [Figure 3] Figure 2 is a cross-sectional view along line BB. [Figure 4] This is an enlarged view showing a cross-section of a hollow tube perpendicular to its longitudinal direction. [Figure 5] This figure shows an example of the manufacturing process for hollow tubes. [Figure 6] This diagram schematically shows the sheath in a bent state. [Figure 7] This figure shows an example of displacement of the hollow tube at the bend in the sheath. [Modes for carrying out the invention]

[0010] The following describes an example of the catheter configuration according to this embodiment, with reference to the drawings. Note that the shapes and dimensions of each part in the drawings are schematic and do not represent the actual shapes and dimensions. In the following description, the end of the catheter furthest from the operator will be referred to as the distal end, and the end closer to the operator will be referred to as the proximal end.

[0011] Figure 1 is a side view showing an example of the catheter 10 of this embodiment. Figure 2 is an enlarged cross-sectional view of the portion of the catheter 10 along line AA. Figure 3 is a cross-sectional view of Figure 2 along line BB.

[0012] The catheter 10 of this embodiment comprises a sheath 20, which is an example of a tubular body; a plurality of operating wires 30 inserted into the sheath 20 along its longitudinal direction; and an operating section 50 provided on the proximal side of the sheath 20, to which the operating wires 30 are connected. In the catheter 10 of the first embodiment, the distal side of the sheath 20 can be bent by individually pulling the operating wires 30 with the operating section 50.

[0013] The sheath 20 is a flexible, elongated tubular body that is inserted into a biological lumen either through an endoscope or directly. The outer diameter of the sheath 20 in this embodiment is such that it can be inserted into blood vessels such as the celiac artery, and peripheral blood vessels such as the hepatic artery and internal carotid artery branches.

[0014] As shown in Figures 2 and 3, the sheath 20 has an inner layer 21, a first reinforcing layer 22, an outer layer 23, an operating wire 30, and a marker 40.

[0015] The inner layer 21 of the sheath 20 is formed into a tubular shape from a biocompatible resin material. The inner layer 21 internally defines a hollow tubular main lumen 21a through which a drug solution, a contrast medium or the like flows. The inner layer 21 can be manufactured by forming a tubular film of the resin material on the surface of a columnar main core wire (not shown), and then pulling the main core wire out of the film. Although not particularly limited, the inner diameter of the sheath 20 (the diameter of the main lumen 21a) may be, for example, 0.5 mm or more and 1.0 mm or less.

[0016] For example, as shown in Figure 2, the cross-sectional shape of the inner layer 21 in the direction perpendicular to the longitudinal direction is circular, and has a substantially uniform thickness in the circumferential direction. The thickness of the inner layer 21 may be uniform over the longitudinal direction, or may vary depending on the position of the sheath 20 in the longitudinal direction. For example, the inner layer 21 may be formed such that the diameter of the main lumen 21a forms a tapered shape that continuously increases from the distal side toward the proximal side.

[0017] As an example, a fluorine-based thermoplastic polymer material can be used as the material of the inner layer 21. Specifically, as the material of the inner layer 21, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), perfluoroalkoxy fluororesin (PFA) or the like can be used. By using a fluorine-based resin for the inner layer 21, the delivery performance when supplying a contrast medium, a drug solution or the like to an affected area through the main lumen 21a of the catheter 10 is improved.

[0018] The first reinforcing layer 22 is disposed concentrically on the outer peripheral side of the inner layer 21, and has a function of reinforcing the inner layer 21 from the outside while maintaining the flexibility of the sheath 20. The first reinforcing layer 22 is formed into a tubular shape by, for example, winding a wire around the inner layer 21, or knitting a wire into a mesh shape.

[0019] As wires applicable to the first reinforcing layer 22, fine metal wires such as tungsten (W), stainless steel (SUS), nickel-titanium alloy, steel, titanium, copper, titanium alloy, or copper alloy can be used, as well as fine polymer fiber wires such as polyimide (PI), polyamide-imide (PAI), or polyethylene terephthalate (PET), which have higher shear strength than the inner layer 21 and outer layer 23. The cross-sectional shape of the wire applicable to the first reinforcing layer 22 is not particularly limited and may be round or flat.

[0020] The outer layer 23 is formed integrally with the inner layer 21 from a biocompatible resin material, forming a tubular shape on the outer circumference of the inner layer 21, and has a substantially uniform thickness in the circumferential direction. The outer layer 23 is radially thicker than the inner layer 21, encloses the first reinforcing layer 22, and constitutes the main wall thickness portion of the sheath 20. In addition, a hydrophilic coating 24 is formed on the outer circumference of the outer layer 23 from a material such as polyvinyl alcohol (PVA) or polyvinylpyrrolidone.

[0021] The outer layer 23 is formed from the same or a different resin material as the inner layer 21. While not particularly limited, a wide range of thermoplastic polymers can be used for the outer layer 23. For example, in addition to the above-mentioned PI, PAI, and PET, polyethylene (PE), polyamide (PA), nylon elastomer, polyurethane (PU), ethylene-vinyl acetate resin (EVA), polyvinyl chloride (PVA), or polypropylene (PP) can be used for the outer layer 23. Furthermore, inorganic fillers such as barium sulfate or bismuth subcarbonate may be mixed into the outer layer 23 to improve its X-ray contrast properties.

[0022] Furthermore, the outer layer 23 has multiple sub-blums 25a and a second reinforcing layer 29 located outside the inner layer 21 and the first reinforcing layer 22.

[0023] Sub-lumines 25a are tubular voids with a smaller diameter than the main lumen 21a, and multiple sub-lumines 25a are arranged around the main lumen 21a at predetermined intervals in the circumferential direction of the outer layer 23. For example, each sub-lumine 25a is arranged in parallel so that its longitudinal direction aligns with the longitudinal direction of the main lumen 21a. Figures 2 and 3 show an example in which two sub-lumines 25a are arranged circumferentially on the outer layer 23 at 180-degree intervals.

[0024] The number and arrangement of sub-lumines 25a within the outer layer 23 are not limited to the above example. For example, three or more sub-lumines 25a may be formed. Also, the sub-lumines 25a may extend at an inclination with respect to the main lumen 21a, including longitudinal and circumferential components.

[0025] Each sub-lumen 25a is formed by a hollow tube 25 embedded in the outer layer 23. The hollow tube 25 is positioned along the main lumen 21a, with its distal end facing the marker 40 and its proximal end introduced into the operating section 50, as shown in Figure 3. An operating wire 30 is slidably inserted inside the hollow tube 25 along the longitudinal direction of the sheath 20. Since the hollow tube 25 through which the operating wire 30 is inserted is positioned outside the first reinforcing layer 22, the main lumen 21a is protected by the first reinforcing layer 22 from the sliding of the operating wire 30.

[0026] The hollow tube 25 is made of the same or a different type of resin material as the inner layer 21, for example. As an example, from the viewpoint of sliding properties with the operating wire 30, the material of the hollow tube 25 can be a fluorine-based polymer material such as PTFE or PVDF, or polyether ether ketone (PEEK), polysulfone (PSF), high-density polyethylene (HDPE), or polyester.

[0027] Figure 4 is an enlarged view showing a cross-section of the hollow tube 25 in a direction perpendicular to the longitudinal direction. The sub-blumen 25a formed inside the hollow tube 25 has a roughly elliptical, flattened annular cross-sectional shape in the direction perpendicular to the longitudinal direction. In the cross-section of the sub-blumen 25a, the length L1 in the first direction D1 (up and down direction in Figure 4) along the radial direction of the sheath 20 is the shortest, and the length L2 in the second direction D2 (left and right direction in Figure 4) perpendicular to the first direction D1 is the longest. Therefore, the length L1 of the sub-blumen 25a in the first direction D1 is shorter than the length L2 of the sub-blumen 25a in the second direction D2 (L1 <L2)。

[0028] Here, if the length L1 of the sub-blum 25a in the first direction D1 is short, the proportion of voids in the radial direction of the outer layer 23 at the location where the sub-blum 25a is placed will decrease. As a result, the amount of resin in the radial direction of the outer layer 23 increases, which can improve the strength of the sheath 20 at the location where the sub-blum 25a is placed.

[0029] On the other hand, as the length L2 of the sub-flumen 25a in the second direction D2 increases, the shape of the sub-flumen 25a becomes flatter, and the end shape of the sub-flumen 25a in the second direction D2 approaches an acute angle, making it easier for fracture due to stress concentration to occur at the end of the sub-flumen 25a in the second direction D2. Also, as the length L2 of the sub-flumen 25a in the second direction D2 increases, shrinkage of the resin film is more likely to occur in the middle portion of the second direction D2 (near the first portion 26 described later) when forming the hollow tube 25.

[0030] As a parameter defining the cross-sectional shape of the sub-blumen 25a, the ratio of the length L2 in the second direction D2 to the length L1 in the first direction D1 of the sub-blumen 25a (L2 / L1) is adjusted within an appropriate range based on the above considerations. For example, it is preferable that the ratio of the length L2 in the second direction D2 to the length L1 in the first direction D1 of the sub-blumen 25a (L2 / L1) is greater than 1 and 4 or less. When the above conditions are met, the strength of the sheath 20 at the location where the sub-blumen 25a is placed is improved, and fracture at the end of the sub-blumen 25a in the second direction D2 can also be suppressed. Furthermore, when the above conditions are met, shrinkage of the resin film in the middle portion of the second direction D2 is less likely to occur, and the yield during the manufacture of the hollow tube 25 is also improved.

[0031] The length L1 of the sub-blumen 25a in the first direction D1 is greater than the outer diameter of the operating wire 30 in order to allow insertion of the operating wire 30 and sliding of the operating wire 30 in the longitudinal direction. Furthermore, even if the catheter 10 is bent and the sub-blumen 25a is deformed, it is necessary to ensure that the sub-blumen 25a is large enough to allow the operating wire 30 to slide in the longitudinal direction within the sub-blumen 25a. For example, if the catheter 10 is a microcatheter, the arithmetic mean of the length L1 of the sub-blumen 25a in the first direction D1 and the length L2 of the sub-blumen 25a in the second direction D2 is preferably between 60 μm and 120 μm. When the above conditions are met, in a microcatheter, it is possible to reduce the overall size of the sub-blumen 25a while suppressing the difficulty of sliding the operating wire 30 in the longitudinal direction within the sub-blumen 25a.

[0032] Furthermore, the hollow tube 25 has an outer circumference shape that is dissimilar to the inner circumference shape that defines the shape of the sub-blume 25a, and the wall thickness of the hollow tube 25 differs in the circumferential direction.

[0033] For example, the wall thickness of the hollow tube 25 is such that the thickness t1 of the first part 26 located in the first direction D1 is greater than the thickness t2 of the second part 27 located in the second direction D2 (t1 > t2).

[0034] The first portion 26 of the hollow tube 25 faces a point in the circumferential direction of the sheath 20 where the amount of resin in the radial direction is small. Therefore, when the sheath 20 is bent or when the internal pressure of the main lumen 21a increases due to the supply of chemicals, stress tends to concentrate in the first portion 26 of the hollow tube 25. Also, since the length L1 in the first direction D1 of the main lumen 21a is shorter than the length L2 in the second direction D2, the first portion 26 of the hollow tube 25 is more likely to come into contact with the operating wire 30 than the second portion 27, and is more likely to be rubbed by the operating wire 30 than the second portion 27. Therefore, by making the thickness t1 of the first portion 26 thicker than the thickness t2 of the second portion 27 as described above, the hollow tube 25 becomes less likely to break, and the strength of the hollow tube 25 and the sheath 20 can be improved.

[0035] If the thickness t1 of the first portion 26 is made too large, the reaction force of the hollow tube 25 against longitudinal compression and tension of the sheath 20 will increase, which may reduce the flexibility of the sheath 20. Therefore, it is preferable that the ratio of the thickness t1 of the first portion 26 to the thickness t2 of the second portion 27 of the hollow tube 25 (t1 / t2) is greater than 1 and 15 or less. When the above conditions are met, the first portion 26 of the hollow tube 25 can be reinforced while suppressing the increase in the reaction force of the hollow tube 25 against longitudinal compression and tension of the sheath 20. As an example, if the catheter 10 is a microcatheter, the thickness t2 of the second portion 27 may be 1 μm or more, and the thickness t1 of the first portion 26 may be 2 μm or more and 15 μm or less.

[0036] Furthermore, if the thickness t1 of the first portion 26 of the hollow tube 25 is too small relative to the inner diameter of the sheath 20, the strength of the first portion 26 of the hollow tube 25 may be insufficient. On the other hand, if the thickness t1 of the first portion 26 of the hollow tube 25 is too large relative to the inner diameter of the sheath 20, the amount of resin in the radial direction of the outer layer 23 may be insufficient in the area where the sub-blum 25a is placed. For this reason, it is preferable that the ratio of the thickness t1 of the first portion 26 to the inner diameter of the sheath 20 be between 0.002 and 0.030. When the above conditions are met, both the strength of the first portion 26 of the hollow tube 25 and the amount of resin in the radial direction of the outer layer 23 in the area where the sub-blum 25a is placed can be secured.

[0037] Furthermore, the hollow tube 25 has thickened sections 28 between the first section 26 and the second section 27 in the circumferential direction. The thickened sections 28 are arranged between the first section 26 and the second section 27 which are alternately formed on the outer circumference of the hollow tube 25, and a total of four thickened sections 28 are formed in the circumferential direction of the hollow tube 25. The cross-sectional shape (circumferential length, thickness distribution, etc.) of each thickened section 28 is substantially the same. Also, the thickness t3 of the thickened section 28 is greater than the thickness t1 of the first section 26.

[0038] Figure 5 shows an example of the manufacturing of the hollow tube 25. The hollow tube 25 of this embodiment can be formed, for example, by applying a solution of the material for the hollow tube 25 to a rounded rectangular core material (sub-core wire 60) for sub-lumines, which has curved ends. The upper and lower surfaces of the sub-core wire 60 each have small protrusions in the center. In Figure 5, the edge portion of the sub-core wire 60 is indicated by an arrow.

[0039] The solution coated onto the sub-core wire 60 spreads and wets the outer surface of the sub-core wire 60 due to surface tension. At this time, the surface tension γ of the sub-core wire 60 S Assuming that the Young-Dupre equation holds, the surface tension γ of the solution L The contact angle θ between the sub-core wire 60 and the solution, and the interfacial tension γ between the solution and the sub-core wire 60. LS Using this, it can be calculated as follows. γ S =γ L cosθ+γ LS

[0040] Here, both surface tension and interfacial tension are vector quantities. Between the flat portion and the edge portion of the sub-core wire 60, the magnitudes of the surface tension and interfacial tension do not change because their physical properties are the same. On the other hand, the contact angle θ between the sub-core wire 60 and the solution changes according to the direction of each tension vector. Therefore, at the edge portion of the sub-core wire 60, the contact angle at the edge portion is different from that at the flat portion, which disrupts the apparent balance of the tension vectors at the edge portion of the sub-core wire 60, causing shrinkage in the coated solution. On the upper and lower sides of the sub-core wire 60, the central part of the coating is concave and thinned, while thicker portions are formed on both sides. This forms the first portion 26 of the hollow tube 25 and the thicker portions 28 on both sides thereof.

[0041] Furthermore, on both sides of the sub-core wire 60, the solution is pulled towards the edge of the sub-core wire 60 by surface tension, forming a thin film on the curved surface that is convex outwards on both sides. Because the coating is stretched on the curved surface on both sides of the sub-core wire 60, the thickness of the coating becomes thinner compared to the central parts on the upper and lower sides. As a result, a second section 27 is formed in the hollow tube 25 that is thinner than the first section 26.

[0042] Then, after the coating dries from the state shown in Figure 5, the sub-core wire 60 is pulled out longitudinally from the hollow tube 25. In this way, a hollow tube 25 (Figure 4) having a sub-blumen 25a inside is formed.

[0043] The second reinforcing layer 29 is positioned outside the main lumen 21a and the multiple sub-lumens 25a, and covers the inner layer 21 and the multiple hollow tubes 25, which are covered by the first reinforcing layer 22, from the outside. The second reinforcing layer 29 prevents the operating wires 30, which are located in the sub-lumens 25a, from being exposed to the outside of the sheath 20, and also functions to position and hold the multiple hollow tubes 25 relative to the inner layer 21 during the manufacturing of the sheath 20.

[0044] The second reinforcing layer 29 is formed, for example, by reinforcing wires 29a that are spirally wound around the inner layer 21 covered by the first reinforcing layer 22 and the multiple hollow tubes 25, and is arranged along the longitudinal direction of the sheath 20. For example, the materials exemplified for the first reinforcing layer 22 can be used for the reinforcing wires 29a of the second reinforcing layer 29. As an example, in this embodiment, flat reinforcing wires 29a are shown, but the configuration of the wires of the first reinforcing layer 22 and the reinforcing wires 29a may be the same or different.

[0045] In the manufacturing process of the sheath 20, a main core wire with an inner layer 21 and a first reinforcing layer 22 formed on its outer circumference, and a sub-core wire 60 (Figure 5) with a hollow tube 25 coating formed on its outer circumference are prepared. The sub-core wires 60 are then arranged in parallel around the main core wire, and the reinforcing wire 29a is wound around it spirally from the outside. This positions the sub-lumen 25a around the main lumen 21a.

[0046] Here, since the cross-sectional shape of the sub-blumen 25a is a flattened annular shape, it is easier to stably position the sub-core wire 60 relative to the main core wire when fixing the sub-core wire 60 to the main core wire. Therefore, according to this embodiment, the sub-core wire 60 is less likely to meander relative to the main core wire during the manufacturing process, and the productivity of the sheath 20 is improved. Furthermore, in this embodiment, the first portion 26 of the hollow tube 25 along the radial direction of the sheath 20 is thick-walled. Therefore, when the reinforcing wire 29a is wound around the coated sub-core wire 60 in the above manufacturing process, the reinforcing wire 29a is buffered by the first portion 26 of the hollow tube 25, and the tightening of the reinforcing wire 29a onto the sub-core wire 60 is eased. This makes it easier to remove the sub-core wire 60 from the hollow tube 25 in a later process.

[0047] The control wires 30 are linear members extending in the longitudinal direction of the sheath 20, with one wire positioned in each sub-lumen 25a, separated by the main lumen 21a. The distal end of each control wire 30 is fixed to the marker 40, and the proximal end of each control wire 30 is connected to the operating unit 50. Furthermore, each control wire 30 is slidable in the longitudinal direction within the sub-lumen 25a by pulling from the operating unit 50.

[0048] The material for the operating wire 30 can be, for example, low-carbon steel (piano wire), stainless steel, corrosion-resistant coated steel wire, titanium or titanium alloy, or tungsten. The operating wire 30 may consist of a single metal wire or a stranded wire of multiple thin metal wires.

[0049] The marker 40 is a ring-shaped member provided at the distal end of the sheath 20 and functions as an indicator when observing the distal end of the sheath 20 from the outside using an X-ray image. The marker 40 is formed from an X-ray contrast-enhanced material such as platinum (Pr), platinum-iridium (PrIr), or tungsten.

[0050] As shown in Figure 3, the marker 40 is fixed to the outer circumference of the inner layer 21 and the first reinforcing layer 22 at the distal end of the sheath 20 and is covered from the outside by the outer layer 23. The distal end of each operating wire 30 is fixed to the marker 40. The manner in which the operating wires 30 are fixed to the marker 40 is not particularly limited, and any configuration such as soldering, heat fusion, adhesive bonding, or mechanical fastening of the operating wires 30 and the marker 40 may be used.

[0051] As shown in Figure 1, the operating unit 50 includes a main body 51 attached to the proximal side of the sheath 20, a hub connector 52, a dial 53, and a stopper 54.

[0052] The main body 51 is a housing that is grasped by the operator when manipulating the catheter 10. The proximal end of the sheath 20 is protected by a tubular protector 55 and then introduced into the main body 51.

[0053] The hub connector 52 is attached to the proximal side of the main body 51, and its tip communicates with the main lumen 21a of the sheath 20. A syringe (not shown) for injecting drug solution, etc., can also be connected to the hub connector 52. By injecting drug solution, etc., into the hub connector 52 from the syringe, the drug solution, etc., is supplied into the biological lumen via the main lumen 21a of the sheath 20.

[0054] The dial 53 is provided on the main body 51 and is a component that can rotate around a rotation axis perpendicular to the longitudinal direction of the sheath 20. The dial 53 has an engagement portion (not shown) with the operating wires 30 that are drawn out from the sheath 20 within the main body 51, and rotation allows for the application of traction force to each operating wire 30 individually.

[0055] In the operating section 50, the operating wire 30 is slid longitudinally by winding one of the operating wires 30 by rotating the dial 53. For example, as shown in Figure 1(b), when the dial 53 is rotated clockwise, one of the operating wires 30 of the sheath 20 slides and is pulled proximally, while the other operating wire 30 becomes slack. As a result, a tensile force is applied to the operating wire 30 that is eccentric to the axis of the sheath 20, and the distal end of the sheath 20 bends toward the side of the operating wire 30 (upper side in the figure).

[0056] Furthermore, for example, as shown in Figure 1(c), when the dial 53 is rotated counterclockwise, the other operating wire 30 of the sheath 20 slides and is pulled proximal, while the other operating wire 30 becomes slack. As a result, a tensile force is applied to the other operating wire 30, which is eccentric with respect to the axis of the sheath 20, and the distal end of the sheath 20 bends toward the other operating wire 30 (downward in the figure). In this way, the distal end of the sheath 20 can be bent in conjunction with the rotation of the dial 53 in the operating section 50.

[0057] The stopper 54 is an operating member provided on the main body 51 and is slidable toward and toward the dial 53. When the stopper 54 is slid toward the dial 53, it engages with the dial 53 and restricts the rotation of the dial 53. By locking the dial 53 in a state where its rotation is restricted by the stopper 54, the catheter 10 can maintain the bent state of the sheath 20.

[0058] Figure 6 schematically shows the sheath 20 in a bent state. Figures 7(a) and 7(b) show examples of displacement of the hollow tube 25 at the bent portion 20a of the sheath 20. In Figures 7(a) and 7(b), the outline of the sub-flumen 25a before displacement is shown by a dashed line.

[0059] When the sheath 20 is bent by the pulling of the operating wire 30, as shown in Figure 6, compression occurs in the longitudinal direction at the bent portion 20a of the sheath 20 on the inner circumference side of the bend (Y side in the figure) relative to the neutral axis Z. Also, tension occurs in the longitudinal direction at the bent portion 20a of the sheath 20 on the outer circumference side of the bend (X side in the figure) relative to the neutral axis Z.

[0060] On the outer circumference of a bend where tension occurs in the longitudinal direction, the outer layer 23 of the bent portion 20a is stretched, causing the hollow tube 25 to be displaced so as to collapse in the radial direction of the sheath 20. At this time, as shown in Figure 7(a), the hollow tube 25 deforms such that the distance between the second portions 27 on the long axis side widens, and the distance between the first portions 26 on the short axis side narrows. In Figure 7(a), the sub-blum 25a expands in a second direction perpendicular to the radial direction of the sheath 20, thereby securing a gap around the operating line 30 on the outer circumference of the bend.

[0061] On the other hand, on the outer circumference side of the bend where compression occurs in the longitudinal direction, the outer layer 23 of the bent portion 20a is also compressed in the circumferential direction, and as shown in Figure 7(b), the hollow tube 25 is displaced to expand in the radial direction of the sheath 20.

[0062] In the hollow tube 25, the thickness t1 of the first section 26 and the thickness t2 of the second section 27 are both smaller than the thickness t8. Therefore, when the outer layer 23 is compressed in the circumferential direction, the second section 27, which is thinner than the thickness 28 and the first section 26, bends first, followed by the first section 26, which is thinner than the thickness 28. On the other hand, the thickness 28 between the first section 26 and the second section 27 is less prone to bending than the first section 26 and the second section 27. As a result, the hollow tube 25 deforms so that the distance between the second sections 27 on the long axis side narrows and the distance between the first sections 26 on the short axis side widens, causing the sub-blumen 25a to deform closer to a circular cross-section.

[0063] As described above, on the inner circumference side of the bend where the operating wire 30 slides in the longitudinal direction, the sub-blume 25a expands in the radial direction (first direction) of the sheath 20, making it less likely for the operating wire 30 to rub against the hollow tube 25 and making it easier for the operating wire 30 to slide.

[0064] The effects of the catheter 10 of this embodiment will be described below. The catheter 10 of this embodiment comprises a sheath 20 (tubular body) having a main lumen 21a and a plurality of sub-lumens 25a arranged around the main lumen 21a and extending along the longitudinal direction of the main lumen 21a, and an operating wire 30 arranged within the sub-lumens 25a and having its distal end fixed to the distal end of the sheath 20. The sub-lumens 25a are formed from hollow resin tubes 25 arranged along the main lumen 21a. The cross-sectional shape of the sub-lumens 25a perpendicular to the longitudinal direction is a flattened annular shape in which the dimension in the first direction D1 along the radial direction of the sheath 20 is shorter than the dimension in the second direction D2 perpendicular to the first direction D1. The thickness t1 of the first portion 26 located in the first direction D1 of the hollow tube 25 is greater than the thickness t2 of the second portion 27 located in the second direction D2 of the hollow tube 25. In this embodiment, by using a sub-blumen 25a with a flattened cross-sectional shape and a short radial opening, it is possible to secure a gap for the operating wire 30 to slide through while suppressing a decrease in the amount of resin in the radial direction of the sheath at the location where the sub-blumen 25a is placed. Furthermore, by making the thickness t1 of the first part 26 thicker than the thickness t2 of the second part 27, the hollow tube 25 becomes less likely to rupture, improving the strength of the hollow tube 25 and the sheath 20. As a result, a catheter 10 with excellent durability of the operating wire 30 and the sub-blumen 25a can be realized.

[0065] Furthermore, in the catheter 10 of this embodiment, the durability of the sub-lumen 25a on which the operating wire 30 slides is improved, which enables the thinning of the sheath 20 or the enlargement of the main lumen 21a. As a result, the delivery of drug solutions and other substances in the catheter 10 can be improved compared to conventional catheters.

[0066] Furthermore, by setting the ratio (t1 / t2) of the thickness t1 of the first portion 26 of the hollow tube 25 to the thickness t2 of the second portion 27 of the hollow tube 25 to be greater than 1 and 15 or less, the first portion 26 of the hollow tube 25 can be reinforced while suppressing the increase in the reaction force of the hollow tube 25 to compression and tension in the longitudinal direction of the sheath 20.

[0067] Furthermore, if the ratio of the length of the sub-blum 25a in the first direction D1 to the length of the sub-blum 25a in the second direction D2 is greater than 1 and 4 or less, the strength of the sheath 20 at the location where the sub-blum 25a is placed will be improved, and fracture at the end of the sub-blum 25a in the second direction D2 will also be suppressed. In addition, shrinkage of the resin film will be less likely to occur in the middle portion of the second direction D2, and the yield during the manufacture of the hollow tube 25 will also be improved.

[0068] Furthermore, by setting the arithmetic mean of the length of the sub-blum 25a in the first direction D1 and the length of the sub-blum 25a in the second direction D2 to 60 μm or more and 120 μm or less, it is possible to reduce the overall size of the sub-blum 25a while suppressing the difficulty of the operating wire 30 within the sub-blum 25a sliding in the longitudinal direction.

[0069] Furthermore, if the ratio of the thickness t1 of the first portion 26 to the inner diameter of the sheath 20 is set to 0.002 or more and 0.030 or less, both the strength of the first portion 26 of the hollow tube 25 and the amount of resin in the radial direction of the outer layer 23 at the location where the sub-blum 25a is placed can be secured.

[0070] Furthermore, the hollow tube 25 of this embodiment has a thick-walled portion 28 between the first portion 26 and the second portion 27 in the circumferential direction, which is thicker than the first portion 26. As a result, on the inner circumference side of the bend of the sheath 20, the distance between the first portions 26 on the short axis side widens, causing the sub-blumen 25a to deform closer to a circular cross-section, making it easier for the operating wire 30 to slide.

[0071] The present invention is not limited to the embodiments described above, and various improvements and design modifications may be made without departing from the spirit of the invention.

[0072] Furthermore, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included.

[0073] Furthermore, the disclosure of the above embodiments encompasses the following technical concepts. (1) A catheter comprising a tubular body having a main lumen and a plurality of sub-lumens arranged around the main lumen and extending along the longitudinal direction of the main lumen, and an operating wire disposed within the sub-lumens and having its distal end fixed to the distal end of the tubular body, wherein the sub-lumens are formed of hollow tubes made of resin arranged along the main lumen, and the cross-sectional shape of the sub-lumens perpendicular to the longitudinal direction is a flattened annular shape in which the dimension in a first direction along the radial direction of the tubular body is shorter than the dimension in a second direction perpendicular to the first direction, and the thickness of a first portion of the hollow tube located in the first direction is greater than the thickness of a second portion of the hollow tube located in the second direction. (2) The catheter according to (1) above, wherein the ratio of the thickness of the first portion to the thickness of the second portion of the hollow tube is greater than 1 and 15 or less. (3) The catheter according to (1) or (2) above, wherein the ratio of the length of the sublumen in the first direction to the length in the second direction is greater than 1 and 4 or less. (4) The catheter according to any one of the above items (1) to (3), wherein the arithmetic mean of the length of the sub-blumen in the first direction and the length in the second direction is 60 μm or more and 120 μm or less. (5) The catheter according to any one of the above items (1) to (4), wherein the ratio of the thickness of the first portion to the inner diameter of the tubular body is 0.002 or more and 0.030 or less. (6) The catheter according to any one of the above items (1) to (5), wherein the hollow tube has a thick-walled portion between the first portion and the second portion in the circumferential direction that is thicker than the first portion. (7) The catheter according to any one of the above items (1) to (6), wherein the distal end of the tubular body is bent by pulling the operating wire proximal to it. (8) The catheter according to any one of (1) to (7) above, wherein the tubular body further comprises a reinforcing wire that is spirally wound radially outward from the hollow tube and arranged along the longitudinal direction. [Explanation of Symbols]

[0074] 10...Catheter, 20...Sheath (tubular body), 20a...Bend, 21...Inner layer, 21a...Main lumen, 22...First reinforcing layer, 23...Outer layer, 24...Hydrophilic coating, 25...Hollow tube, 25a...Sub-lumen, 26...First section, 27...Second section, 28...Thick-walled section, 29...Second reinforcing layer, 29a...Reinforcing wire, 30...Operating wire, 40...Marker, 50...Operating section, 51...Main body, 52...Hub connector, 53...Dial, 54...Stopper, 55...Protector, 60...Sub-core wire

Claims

1. A tubular body having a main lumen and a plurality of sub-lumens arranged around the main lumen and extending along the longitudinal direction of the main lumen, The system comprises an operating wire disposed within the sub-blumen, the distal end of which is fixed to the distal end of the tubular body, The sub-lumen is formed of a hollow resin tube arranged along the main lumen, The cross-sectional shape of the sub-blumen perpendicular to the longitudinal direction is a flattened annular shape in which the dimension in the first direction along the radial direction of the tubular body is shorter than the dimension in the second direction perpendicular to the first direction. The thickness of the first portion of the hollow tube located in the first direction is greater than the thickness of the second portion of the hollow tube located in the second direction. catheter.

2. The ratio of the thickness of the first portion to the thickness of the second portion of the hollow tube is greater than 1 and less than or equal to 15. The catheter according to claim 1.

3. The ratio of the length of the sub-flumen in the first direction to the length of the sub-flumen in the second direction is greater than 1 and less than or equal to 4. The catheter according to claim 1.

4. The arithmetic mean of the length of the sub-blumen in the first direction and the length in the second direction is 60 μm or more and 120 μm or less. The catheter according to claim 1.

5. The ratio of the thickness of the first portion to the inner diameter of the tubular body is 0.002 or more and 0.030 or less. The catheter according to claim 1.

6. The hollow tube has a thicker walled portion between the first portion and the second portion in the circumferential direction, which is thicker than the first portion. The catheter according to claim 1.

7. The distal end of the tubular body bends when the operating wire is pulled towards the proximal end. The catheter according to claim 1.

8. The tubular body further comprises reinforcing wires that are spirally wound radially outward from the hollow tube and arranged along the longitudinal direction. The catheter according to claim 1.

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