Catheter shaft and catheter

Abstract

To improve ease of insertion and withdrawal of a treatment instrument to a working channel.SOLUTION: A catheter shaft 2 comprises an outer layer 38 and an inner layer 40. The inner layer 40 has: at least one working channel 42; at least four pull wire lumens 44; and at least one sensor lumen 46. The working channel 42 is eccentric with respect to a shaft center C1 of the catheter shaft 2. In a cross section view orthogonal to the shaft of the catheter shaft 2, the shortest distance from an outer peripheral surface of an outer layer 38 of a part 42A closest to an outer peripheral surface of the outer layer 38 on the working channel 42, is longer than the shortest distances from the outer peripheral surface of the outer layer 38 of parts 44A, 46A closest to the outer peripheral surface of the outer layer 38 on each pull wire lumen 44 and the sensor lumen 46.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to catheter shafts and catheters. [Background technology]

[0002] Patent Document 1 discloses a catheter shaft including a camera channel through which a camera is inserted, a forceps channel through which forceps are inserted, and a plurality of pull wire lumens. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022 / 172321 Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors have conducted extensive research into a catheter shaft having a working channel through which a treatment tool such as forceps is passed, and multiple lumens through which sensors including a camera, pull wires, etc. are passed, and as a result, have come up with a shaft structure that can improve the ease of inserting and removing a treatment tool into and from the working channel.

[0005] The present disclosure has been made in light of these circumstances, and has as its objective to provide a technique for improving the ease of inserting and removing a treatment tool into and from a working channel. [Means for solving the problem]

[0006] An embodiment of the present disclosure is a catheter shaft. The catheter shaft includes an outer layer and an inner layer covered by the outer layer. The inner layer includes at least one working channel through which a treatment tool is passed, at least four pull wire lumens through which pull wires are passed, and at least one sensor lumen through which at least a portion of a sensor is passed. The working channel is eccentric with respect to the axis of the catheter shaft. In at least a portion of the catheter shaft, in a cross-sectional view perpendicular to the axis of the catheter shaft, the shortest distance from the outer circumferential surface of the outer layer to the part of the working channel closest to the outer circumferential surface of the outer layer is longer than the shortest distance from the outer circumferential surface of the outer layer to the part of each pull wire lumen closest to the outer circumferential surface of the outer layer and the shortest distance from the outer circumferential surface of the outer layer to the part of the sensor lumen closest to the outer circumferential surface of the outer layer.

[0007] Another aspect of the present disclosure is a catheter shaft. The catheter shaft includes an outer layer and an inner layer covered by the outer layer. The inner layer includes at least one working channel tube forming a working channel through which a treatment tool is passed, at least four pull wire lumen tubes forming pull wire lumens through which pull wires are passed, and at least one sensor lumen tube forming a sensor lumen through which at least a part of a sensor is passed. The working channel tube is eccentric with respect to the axis of the catheter shaft. In at least a part of the catheter shaft, in a cross-sectional view perpendicular to the axis of the catheter shaft, each pull wire lumen tube and sensor lumen tube are in contact with the outer layer, and the working channel tube is not in contact with the outer layer.

[0008] Another aspect of the present disclosure is a catheter, comprising the catheter shaft of any of the above aspects and a handle located on the proximal end side of the catheter shaft.

[0009] Any combination of the above components and any conversion of the expression of the present disclosure between a method, an apparatus, a system, etc. are also valid as aspects of the present disclosure. Effect of the Invention

[0010] According to the present disclosure, it is possible to improve the ease of inserting and removing a treatment tool into and from a working channel. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a plan view of a catheter according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view of the tip of the catheter. [Diagram 3] FIG. 2 is a perspective view of the tip of the catheter. [Figure 4] FIG. 1 is a cross-sectional view of a catheter shaft according to a first embodiment. [Diagram 5] Fig. 5(A) is a cross-sectional view taken along line AA in Fig. 4. Fig. 5(B) is a cross-sectional view taken along line BB in Fig. 4. [Figure 6] FIG. 13 is a diagram for explaining the arrangement of a pull wire lumen. [Figure 7] FIG. 11 is a cross-sectional view of a catheter shaft according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present disclosure will be described below with reference to the drawings based on preferred embodiments. The embodiments are illustrative and do not limit the present disclosure, and all features and combinations thereof described in the embodiments are not necessarily essential to the present disclosure. The same or equivalent components, members, and processes shown in each drawing are given the same reference numerals, and duplicated descriptions are omitted as appropriate. In addition, the scale and shape of each part shown in each drawing are set for convenience to facilitate explanation, and are not to be interpreted as being limiting unless otherwise specified. In addition, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not represent any order or importance, but are intended to distinguish one configuration from another. In addition, some of the members that are not important in explaining the embodiment in each drawing are omitted.

[0013] (Embodiment 1) 1 is a plan view of a catheter 1 according to embodiment 1. The catheter 1 can be used for treating organs of a living body, such as the bile duct or pancreatic duct. The catheter 1 includes a catheter shaft 2, a handle 4, and a distal tip 6.

[0014] The catheter shaft 2 is a long tubular member. Examples of the material of the catheter shaft 2 include flexible materials such as resin. The length of the catheter shaft 2 is, for example, 200 mm to 4800 mm. A handle 4 is provided at the base end (proximal end) of the catheter shaft 2. A distal tip 6 is provided at the tip (distal end) of the catheter shaft 2. In the following, the distal tip 6 side of the catheter 1 and each member constituting the catheter 1 will be referred to as the "distal side" and the handle 4 side will be referred to as the "base side". In addition, the direction in which the axis of the catheter shaft 2 extends will be referred to as the "axial direction", the direction perpendicular to the axis will be referred to as the "radial direction", and the direction around the axis will be referred to as the "circumferential direction".

[0015] Although details will be described later, the catheter shaft 2 has one working channel 42, four pull wire lumens 44, one sensor lumen 46, and two fluid lumens 48 (see FIG. 4). A pull wire 56 is passed through each pull wire lumen 44.

[0016] The catheter shaft 2 has a tip region 2A that can be intentionally curved by pulling the pull wire 56. The tip region 2A can be formed in a desired range by, for example, varying the hardness (e.g., Shore D hardness) of the resin constituting the catheter shaft 2 between the tip region 2A and a region on the proximal side of the tip region 2A. The tip region 2A is, for example, a region up to 50 mm from the tip of the catheter shaft 2.

[0017] The handle 4 is disposed outside the body and operated by a practitioner such as a doctor. The handle 4 includes, for example, a grip 8, two operation knobs 10 and 12, a working channel port 14, a sensor port 16, and a fluid port (not shown).

[0018] The grip 8 is held by the practitioner. The base ends of two pull wires 56 are attached to the operation knob 10. The base ends of the remaining two pull wires 56 are attached to the operation knob 12. When the operation knob 10 rotates in one direction, one of the pull wires 56 connected to the operation knob 10 is pulled toward the base end. When the operation knob 10 rotates in the other direction, the other pull wire 56 connected to the operation knob 10 is pulled toward the base end. When the operation knob 12 rotates in one direction, one of the pull wires 56 connected to the operation knob 12 is pulled toward the base end. When the operation knob 12 rotates in the other direction, the other pull wire 56 connected to the operation knob 12 is pulled toward the base end. By pulling the four pull wires 56, the distal end region 2A can be bent in multiple directions. The technique of bending the distal end region 2A using the pull wires 56 is known, so further detailed description will be omitted.

[0019] The working channel port 14 is connected to the working channel 42. A practitioner can insert and remove a treatment tool into and from the working channel 42 via the working channel port 14. The sensor port 16 is connected to a sensor lumen 46. A sensor cable 18 is passed through the sensor lumen 46 via the sensor port 16. As an example, a connector 20 is provided on the cable 18, and the cable 18 is fixed to the handle 4 by attaching the connector 20 to the sensor port 16. The fluid port is connected to the fluid lumen 48.

[0020] The distal tip 6 is fitted onto the distal end of the catheter shaft 2. When the distal end of the catheter shaft 2 is inserted into the body, the distal tip 6 is delivered to a treatment site within the body. Figures 2 and 3 are perspective views of the distal end of the catheter 1. Note that Figures 2 and 3 show a state in which the portion of the outer layer 38 that overlaps with the distal tip 6 has been cut away. Also, the pull wire 56 is not shown in Figure 3.

[0021] The distal tip 6 is a roughly cylindrical member extending in the axial direction of the catheter shaft 2. The material of the distal tip 6 is, for example, the same as that of the catheter shaft 2. The distal tip 6 has a first through hole 22 extending from the distal end to the proximal end. The proximal end side of the first through hole 22 communicates with the working channel 42.

[0022] The distal tip 6 has a sensor groove 24 at its distal end. A sensor lumen 46 is connected to the bottom of the sensor groove 24. The catheter 1 of this embodiment has a camera module 26 as a sensor. The camera module 26 is composed of a camera head 28 equipped with a CMOS image sensor, and a cable 18 extending from the camera head 28. The camera head 28 is fitted into the sensor groove 24. The cable 18 is passed through the sensor lumen 46.

[0023] The distal tip 6 has four pull wire grooves 30 on the base end side of the outer circumferential surface. Each pull wire groove 30 has a narrow portion 32 extending axially from the base end of the distal tip 6, and a wide portion 34 located at the tip of the narrow portion 32 and wider than the narrow portion 32. The base end of the narrow portion 32 is connected to the pull wire lumen 44. A pull wire 56 is fitted into the pull wire grooves 30. The pull wire 56 has a small diameter portion 58 and a large diameter portion 60. The small diameter portion 58 extends into the pull wire lumen 44, and the tip side protrudes from the pull wire lumen 44 and is fitted into the narrow portion 32. The large diameter portion 60 is located at the tip of the small diameter portion 58 and is fitted into the wide portion 34. When the pull wire 56 is pulled toward the base end by operating the operation knobs 10, 12, the large diameter portion 60 is caught on the step between the wide portion 34 and the narrow portion 32, and the displacement toward the base end is restricted. This allows the distal end region 2A to be bent by the pulling operation of the pull wire 56.

[0024] The distal tip 6 has two second through holes 36 extending from the distal end to the proximal end. The proximal end side of one of the second through holes 36 is connected to one of the fluid lumens 48. The proximal end side of the other of the second through holes 36 is connected to the other of the fluid lumens 48. In this embodiment, the proximal end portion of the second through hole 36 is exposed on the outer circumferential surface of the distal tip 6. In other words, the proximal end portion of the second through hole 36 is groove-shaped.

[0025] Next, the structure of the catheter shaft 2 will be described in detail. Fig. 4 is a cross-sectional view of the catheter shaft 2 according to the first embodiment. Fig. 5(A) is a cross-sectional view taken along line AA in Fig. 4. Fig. 5(B) is a cross-sectional view taken along line BB in Fig. 4. Fig. 4 shows a cross-section perpendicular to the axis of the catheter shaft 2, and Figs. 5(A) and 5(B) show cross-sections parallel to the axis. Note that the cable 18 and the pull wire 56 are omitted from Figs. 5(A) and 5(B).

[0026] The catheter shaft 2 includes an outer layer 38 and an inner layer 40 that is covered by the outer layer 38. The inner layer 40 also includes a working channel 42, four pullwire lumens 44, a sensor lumen 46, and two fluid lumens 48. These channels and lumens are contained within the inner layer 40 and are separated from one another within the inner layer 40.

[0027] The outer layer 38 is a tubular member having a single lumen structure. The inner layer 40 is a tubular member having a multi-lumen structure. The inner layer 40 is housed in the outer layer 38. The tip of the inner layer 40 is located closer to the base end of the catheter shaft 2 than the tip of the outer layer 38. The tip tip 6 is inserted into the recessed portion of the inner layer 40 at the tip of the catheter shaft 2.

[0028] The material of the outer layer 38 is exemplified by synthetic resins having good slip properties, mechanical strength, flexibility and biocompatibility, such as polyether block amide (PEBAX). The material of the inner layer 40 is exemplified by synthetic resins such as polyolefin, polyamide, polyether block amide, polyurethane, nylon, polyester, etc. The constituent materials of the outer layer 38 and the inner layer 40 may be mixed with a contrast agent, a pigment, etc. The hardness of the outer layer 38 and the inner layer 40 may be different. For example, the outer layer 38 has a higher hardness than the inner layer 40. Note that the inner layer 40 may have a higher hardness than the outer layer 38, or the inner layer 40 and the outer layer 38 may have the same hardness.

[0029] The outer layer 38 has a first reinforcing layer 50 on its inner circumferential surface. In this embodiment, the first reinforcing layer 50 is interpreted as a part of the outer layer 38. The first reinforcing layer 50 is, for example, composed of a coil in which a wire is wound in a spiral shape. The first reinforcing layer 50 may be composed of a braid in which a plurality of wires are woven into a cylindrical shape. Examples of materials for the wire include biocompatible metals such as tungsten, stainless steel, and nickel titanium, and biocompatible materials such as nylon, polyether ketone (PEEK), and liquid crystal polymer. The outer layer 38 has the first reinforcing layer 50, which makes it easier to maintain the shape of the channel or lumen contained in the inner layer 40. In addition, FIG. 4 shows the first reinforcing layer 50 in a schematic manner.

[0030] The working channel 42 is a tube extending from the base end to the tip end of the catheter shaft 2, and is a passage for a treatment tool inserted or removed from the working channel port 14. Examples of treatment tools include forceps, cannula, dilator, guide wire, snare, injection needle, high-frequency knife, stent, etc. The number of working channels 42 may be two or more. The working channel 42 is formed by a working channel tube 52 embedded in the inner layer 40. In other words, the inner surface of the working channel tube 52 defines the working channel 42, and the internal space of the working channel tube 52 forms the working channel 42.

[0031] The base end of the working channel tube 52 communicates with the working channel port 14. The tip of the working channel tube 52 communicates with the first through-hole 22. Examples of materials for the working channel tube 52 include synthetic resins with good slip properties, such as polytetrafluoroethylene (PTFE) and perfluoroalkoxyalkane (PFA).

[0032] The inner layer 40 has a second reinforcing layer 54 surrounding the working channel 42. The inner layer 40 of this embodiment has the second reinforcing layer 54 at the interface with the working channel tube 52. The second reinforcing layer 54 is not in contact with the outer layer 38. In other words, the inner layer 40 is interposed between the second reinforcing layer 54 and the outer layer 38. The second reinforcing layer 54 is made of a coil or braid, for example, like the first reinforcing layer 50. The inner layer 40 has the second reinforcing layer 54, which makes it easier to maintain the shape of the working channel 42. Note that the second reinforcing layer 54 is shown in FIG. 4 as a schematic diagram.

[0033] Each of the four pullwire lumens 44 is a tube extending from the base end to the tip end of the catheter shaft 2, through which a pullwire 56 is passed and accommodated. The number of pullwire lumens 44 may be at least four, but is preferably four. Each pullwire lumen 44 is formed by a pullwire lumen tube 62 embedded in the inner layer 40. In other words, the inner surface of the pullwire lumen tube 62 defines the pullwire lumen 44, and the internal space of each pullwire lumen tube 62 forms the pullwire lumen 44.

[0034] A proximal end of each pull wire lumen tube 62 communicates with the operation knob 10 or the operation knob 12. A distal end of each pull wire lumen tube 62 communicates with the pull wire groove 30. The material of the pull wire lumen tube 62 is the same as that of the working channel tube 52, for example.

[0035] The sensor lumen 46 is a tube extending from the base end to the tip end of the catheter shaft 2, through which at least a part of the sensor is passed and accommodated. In this embodiment, the cable 18 is passed through the sensor lumen 46 as part of the sensor. Examples of the cable 18 include a power cable and a signal cable. The sensor itself may be passed through the sensor lumen 46. Examples of sensors mounted on the catheter 1 include a thermocouple, an ultrasonic sensor, an optical sensor, a pressure sensor, and the like, in addition to the camera module 26. The number of sensor lumens 46 may be two or more. The sensor lumen 46 is formed by a sensor lumen tube 64 embedded in the inner layer 40. That is, the inner surface of the sensor lumen tube 64 defines the sensor lumen 46, and the internal space of the sensor lumen tube 64 becomes the sensor lumen 46.

[0036] The base end of the sensor lumen tube 64 communicates with the sensor port 16. The tip of the sensor lumen tube 64 communicates with the sensor groove 24. The material of the sensor lumen tube 64 is the same as that of the working channel tube 52, for example.

[0037] The two fluid lumens 48 are tubes extending from the base end to the tip end of the catheter shaft 2, and are passages through which a fluid flows. Examples of fluids that flow through the fluid lumens 48 include physiological saline supplied to the treatment site and body fluids (blood and tissue fluid) collected from the treatment site. The number of fluid lumens 48 may be one, three or more, or may be omitted. Each fluid lumen 48 is formed by a fluid lumen tube 66 embedded in the inner layer 40. In other words, the inner surface of the fluid lumen tube 66 partitions the fluid lumen 48, and the internal space of each fluid lumen tube 66 forms the fluid lumen 48.

[0038] The base end of each fluid lumen tube 66 is connected to a fluid port. The tip end of each fluid lumen tube 66 is connected to the second through-hole 36. The physiological saline solution sent to the tip end side of the catheter shaft 2 via the fluid lumen 48 is discharged from the second through-hole 36 to wash the treatment site. The treatment site can also be washed by sucking the body fluid accumulated in the treatment site from the second through-hole 36 and collecting it to the base end side of the catheter shaft 2 via the fluid lumen 48. This ensures the field of view of the camera module 26 and the field of view of the practitioner. The material of the fluid lumen tube 66 is the same as that of the working channel tube 52, for example.

[0039] Next, the arrangement of the channels and lumens contained in the inner layer 40 will be described. The working channel 42 and the working channel tube 52 are eccentric with respect to the axis C1 of the catheter shaft 2. In other words, the axis C2 of the working channel 42 and the working channel tube 52 is offset from the axis C1 of the catheter shaft 2. The axis C1 of the catheter shaft 2 is substantially the same as the axis of the outer layer 38.

[0040] In addition, in a cross section perpendicular to the axis of the catheter shaft 2, the shortest distance from the outer periphery of the outer layer 38 to the portion 42A of the working channel 42 closest to the outer periphery of the outer layer 38 is longer than the shortest distance from the outer periphery of the outer layer 38 to the portion 44A of each pullwire lumen 44, the shortest distance from the outer periphery of the outer layer 38 to the portion 46A of the sensor lumen 46 closest to the outer periphery of the outer layer 38, and the shortest distance from the outer periphery of the outer layer 38 to the portion 48A of the fluid lumen 48 closest to the outer periphery of the outer layer 38. In other words, although the axis C2 of the working channel 42 is offset from the axis C1 of the catheter shaft 2, it is closer to the axis C1 than the axes of the pullwire lumen 44, the sensor lumen 46, and the fluid lumen 48. Even if there are two or more working channels 42, five or more pullwire lumens 44, two or more sensor lumens 46, or one or three or more fluid lumens 48, each channel and lumen is positioned so as to satisfy the positional relationships described above.

[0041] In a cross-sectional view perpendicular to the axis of the catheter shaft 2, the pull wire lumen tubes 62, the sensor lumen tube 64, and the fluid lumen tube 66 are in contact with the outer layer 38, while the working channel tube 52 is not in contact with the outer layer 38. In this embodiment, the outer layer 38 has the first reinforcing layer 50 on the surface facing the inner layer 40. Therefore, the pull wire lumen tubes 62, the sensor lumen tube 64, and the fluid lumen tube 66 are in contact with the first reinforcing layer 50, while the working channel tube 52 is not in contact with the first reinforcing layer 50. In other words, although the axis C2 of the working channel tube 52 is offset from the axis C1 of the catheter shaft 2, it is closer to the axis C1 than the axes of the pull wire lumen tube 62, the sensor lumen tube 64, and the fluid lumen tube 66.

[0042] In this embodiment, "the tube is in contact with the outer layer 38 or the first reinforcing layer 50" means that the inner layer 40 is not interposed between the tube and the outer layer 38 or the first reinforcing layer 50. Moreover, "the tube is not in contact with the outer layer 38 or the first reinforcing layer 50" means that the inner layer 40 is interposed between the tube and the outer layer 38 or the first reinforcing layer 50. Note that, during the manufacturing process of the catheter shaft 2, the resin component constituting the outer layer 38 and the resin component constituting the inner layer 40 may melt and mix with each other. In this embodiment, the portion at the boundary between the outer layer 38 and the inner layer 40 where the resin components of both layers mix with each other is included in the outer layer 38.

[0043] When the working channel 42 is eccentric with respect to the axis C1 of the catheter shaft 2, a thin-walled portion is likely to be formed in the inner layer 40 interposed between the working channel 42 and the outer layer 38. As a result of intensive research, the present inventors have found that the presence of a thin-walled portion may cause wrinkles to form on the side wall of the working channel 42 or the wrinkles to become larger when the catheter shaft 2 is curved. In particular, it was confirmed that when the thickness of the thin-walled portion is less than 0.28 mm, the tendency for wrinkles to form is strong, and the wrinkles formed become larger as the thickness becomes thinner, and the wrinkles formed become significantly larger when the thickness is 0.1 mm or less. When the wrinkles formed in the working channel 42 become large, it becomes difficult to insert and remove the treatment tool, and the operability of the treatment tool may decrease. This problem was first discovered by the present inventors, and should not be taken as a general understanding of those skilled in the art.

[0044] To address this issue, the forceps channel 42 is arranged as described above, which can prevent a thin wall from being formed around the forceps channel 42 and prevent wrinkles from being generated. Alternatively, the wrinkles that are formed can be prevented from becoming large. As a result, the ease of inserting and removing a treatment tool into and from the forceps channel 42 can be improved. This also improves the operability of a procedure using the catheter 1.

[0045] In addition, by bringing the axis C2 of the working channel 42 closer to the axis C1 of the catheter shaft 2, it becomes easier to secure the installation space for the second reinforcing layer 54. Furthermore, by providing the second reinforcing layer 54, it becomes possible to further suppress the occurrence or enlargement of wrinkles. In addition, by bringing the axis C2 of the working channel 42 closer to the axis C1 of the catheter shaft 2, it becomes easier for the treatment tool to enter the angle of view of the camera module 26. This makes it easier to operate the treatment tool. In the above description of the occurrence or enlargement of wrinkles and the suppression of the occurrence or enlargement, the working channel 42 can also be read as the working channel tube 52.

[0046] In this embodiment, the camera head 28 is fixed to the distal tip 6 and is not inserted into the sensor lumen 46. Therefore, only the cable 18 is inserted into the sensor lumen 46. For this reason, the diameter of the sensor lumen 46 can be made smaller than when the entire camera module 26 is inserted into the sensor lumen 46, for example, for the purpose of reusing the camera module 26. This makes it easier to bring the axis C2 of the working channel 42 and the working channel tube 52 closer to the axis C1 of the catheter shaft 2.

[0047] In addition, in a cross-sectional view perpendicular to the axis of the catheter shaft 2, the working channel 42, the pullwire lumen 44, and the sensor lumen 46 have an approximately circular shape, while the fluid lumen 48 has an elongated hole shape. This makes it possible to increase the cross-sectional area of ​​the fluid lumen 48 and ensure a sufficient flow rate of the fluid while preventing the fluid lumen 48 from interfering with the layout design that brings the axis C2 of the working channel 42 and the working channel tube 52 closer to the axis C1 of the catheter shaft 2.

[0048] In addition, by bringing the axis C2 of the working channel 42 and the working channel tube 52 closer to the axis C1 of the catheter shaft 2, the four pull wire lumens 44 can be easily arranged evenly in the circumferential direction of the catheter shaft 2. FIG. 6 is a diagram for explaining the arrangement of the pull wire lumens 44. Note that the cable 18 and the pull wire 56 are not shown in FIG. 6. In this embodiment, when four imaginary lines are assumed to connect the axis C1 of the catheter shaft 2 and the axis C3 of each pull wire lumen in a cross section perpendicular to the axis of the catheter shaft 2, the difference between the angles formed by two adjacent imaginary lines in the circumferential direction and each of the other angles is preferably 35° or less, more preferably 30° or less, and even more preferably 25° or less.

[0049] Specifically, a virtual line connecting the axis C1 and the axis C3 of the pull wire lumen 44 located at the upper left in FIG. 6 is defined as a virtual line L1. A virtual line connecting the axis C1 and the axis C3 of the pull wire lumen 44 located at the upper right in FIG. 6 is defined as a virtual line L2. A virtual line connecting the axis C1 and the axis C3 of the pull wire lumen 44 located at the lower right in FIG. 6 is defined as a virtual line L3. A virtual line connecting the axis C1 and the axis C3 of the pull wire lumen 44 located at the lower left in FIG. 6 is defined as a virtual line L4. An angle between the virtual line L1 and the virtual line L2 is defined as an angle θ1. An angle between the virtual line L2 and the virtual line L3 is defined as an angle θ2. An angle between the virtual line L3 and the virtual line L4 is defined as an angle θ3. An angle between the virtual line L4 and the virtual line L1 is defined as an angle θ4. In this case, the difference between each of the angles θ1 to θ4 and the other angles is 35° or less.

[0050] For example, when the diameter of the catheter shaft 2 is 3.8 mm and the diameter of the working channel 42 is 2 mm, the difference between angles θ1 to θ4 can be made approximately 0. When the diameter of the catheter shaft 2 is 3.1 mm and the diameter of the working channel 42 is 1.2 mm, the difference between angles θ1 to θ4 can be made 15° or less.

[0051] Such an arrangement of the pull wire lumens 44 can suppress differences in the degree of bending of the tip region 2A and in the operability of the operation knobs 10, 12 depending on the direction in which the tip region 2A is bent. This improves the operability of the catheter 1. The four pull wire lumens 44 are disposed at approximately equal distances from the axis C1 of the catheter shaft 2. For example, in a cross-sectional view perpendicular to the axis of the catheter shaft 2, the difference in distance from the axis C1 to the axis C3 of each pull wire lumen 44 is 15% or less of the radius of the catheter shaft 2.

[0052] The above-mentioned arrangement of the channels and lumens, and the arrangement of the tubes may be satisfied in at least a part of the catheter shaft 2 in the axial direction of the catheter shaft 2, but it is preferable that they are satisfied in at least a part of the tip region 2A, more preferable that they are satisfied in the region including the apex of the curvature in the tip region 2A, and even more preferable that they are satisfied in the entire tip region 2A.

[0053] The catheter shaft 2 is configured as an integrally molded product. The molding method for obtaining this integrally molded product is not particularly limited. In one example of a manufacturing method for the catheter shaft 2, the working channel tube 52, the pull wire lumen tube 62, the sensor lumen tube 64, and the fluid lumen tube 66 are first prepared in a state of being arranged on the outer periphery of a mandrel. At this time, each tube prepared in advance may be placed on the mandrel, or each tube may be formed on the outer periphery of the mandrel by extrusion molding.

[0054] Next, the second reinforcing layer 54 is formed on the outer periphery of the working channel tube 52. For example, a wire is sent out from the braider and wound around the outer periphery of the working channel tube 52 to form the coil-shaped second reinforcing layer 54. Next, the molten resin constituting the inner layer 40 is extruded from the extruder to extrude the inner layer 40 so as to embed each tube. Next, the first reinforcing layer 50 is formed on the outer periphery of the inner layer 40. For example, a wire is sent out from the braider and wound around the outer periphery of the inner layer 40 to form the coil-shaped first reinforcing layer 50. Next, the molten resin constituting the outer layer 38 is extruded from the extruder to extrude the outer layer 38 so as to cover the inner layer 40. The catheter shaft 2 is obtained by the above steps.

[0055] (Embodiment 2) The catheter 1 according to the present embodiment has a configuration generally in common with the catheter 1 according to embodiment 1, except that the fluid lumen 48 has an additional function. Below, the catheter 1 according to embodiment 2 will be described, focusing on the configuration that differs from embodiment 1, and the common configuration will be described briefly or omitted.

[0056] Fig. 7 is a cross-sectional view of the catheter shaft 2 according to embodiment 2. Fig. 7 shows a cross section perpendicular to the axis of the catheter shaft 2. Note that in Fig. 7, the cable 18 and the pull wire 56 are omitted from illustration.

[0057] In the catheter shaft 2 of this embodiment, in a cross-sectional view perpendicular to the axis of the catheter shaft 2, the shortest distance from the outer peripheral surface of the outer layer 38 to the portion 42A of the working channel 42 closest to the outer peripheral surface of the outer layer 38 is longer than the shortest distance from the outer peripheral surface of the outer layer 38 to the portion 44A of each pullwire lumen 44, the shortest distance from the outer peripheral surface of the outer layer 38 to the portion 44A of the outer peripheral surface of the outer layer 38 closest to the outer peripheral surface of the outer layer 38 to the portion 46A of the sensor lumen 46, and the shortest distance from the outer peripheral surface of the outer layer 38 to the portion 48A of the fluid lumen 48 closest to the outer peripheral surface of the outer layer 38 (see FIG. 4).

[0058] In addition, in a cross-sectional view perpendicular to the axis of the catheter shaft 2, the pull wire lumen tubes 62, the sensor lumen tube 64, and the fluid lumen tube 66 are in contact with the outer layer 38, while the working channel tube 52 is not in contact with the outer layer 38. In addition, the pull wire lumen tubes 62, the sensor lumen tube 64, and the fluid lumen tube 66 are in contact with the first reinforcing layer 50, while the working channel tube 52 is not in contact with the first reinforcing layer 50.

[0059] In addition, the fluid lumen 48 in this embodiment also serves as a guidewire lumen through which the guidewire 68 is passed. If the catheter shaft 2 does not have a guidewire lumen, the guidewire 68 is passed through the working channel 42. However, if the guidewire 68 and the treatment tool are passed through the working channel 42 at the same time, the guidewire 68 may interfere with the insertion / removal and operation of the treatment tool, so it is desirable to avoid simultaneous insertion. For this reason, the guidewire 68 that is passed through the working channel 42 may be pulled out once to pass the treatment tool through, or vice versa. As a result, the operability of the procedure using the catheter 1 may be reduced.

[0060] In contrast, if a fluid and a guidewire 68 are passed through the fluid lumen 48 at the same time, they will not interfere with each other, or the degree of interference will be low. Therefore, the fluid lumen 48 can be used as a guidewire lumen. By using the fluid lumen 48 as a guidewire lumen, the operability of a procedure using the catheter 1 can be improved.

[0061] The fluid lumen 48 in this embodiment has an approximately perfect circular shape in a cross section perpendicular to the axis of the catheter shaft 2. The guidewire 68 generally has an approximately perfect circular cross section. Therefore, by making the cross section of the fluid lumen 48 approximately perfect circular, it is possible to more easily prevent the guidewire 68 from contacting the side wall of the fluid lumen 48 compared to the case where the cross section is an elongated hole shape as in the first embodiment.

[0062] Even if the cross section of fluid lumen 48 is made to be approximately a perfect circle, the difference between angles θ1 to θ4 formed by imaginary lines L1 to L4 can be made 35° or less. For example, when the diameter of catheter shaft 2 is 3.8 mm, the diameter of working channel 42 is 2 mm, the diameter of one fluid lumen 48 is 0.85 mm, and the diameter of the other fluid lumen 48 is 0.8 mm, the difference between angles θ1 to θ4 can be made 32° or less.

[0063] The above describes the embodiments of the present disclosure in detail. The above-mentioned embodiments merely show specific examples of implementing the present disclosure. The contents of the embodiments do not limit the technical scope of the present disclosure, and many design changes such as changes, additions, and deletions of components are possible within the scope of the idea of ​​the present disclosure defined in the claims. A new embodiment with a design change has the effects of each of the combined embodiments and modifications. In the above-mentioned embodiments, the contents for which such design changes are possible are emphasized by adding notations such as "in this embodiment" and "in this embodiment", but design changes are permitted even in contents without such notations. Any combination of components included in each embodiment is also valid as an aspect of the present disclosure. The hatching on the cross section of the drawing does not limit the material of the object to which the hatching is added.

[0064] The embodiment may be specified by the items described below. [1st item] A catheter shaft (2), An outer layer (38); an inner layer (40) covered with an outer layer (38); The inner layer (40) is provided with at least one working channel (42) through which a treatment tool is passed, at least four pull wire lumens (44) through which pull wires (56) are passed, and at least one sensor lumen (46) through which at least a portion of a sensor (18) is passed; The working channel (42) is eccentric with respect to the axis (C1) of the catheter shaft (2); in at least a portion of the catheter shaft (2), in a cross-sectional view perpendicular to the axis of the catheter shaft (2), the shortest distance from the outer circumferential surface of the outer layer (38) to a portion (42A) of the working channel (42) closest to the outer circumferential surface of the outer layer (38) is longer than the shortest distance from the outer circumferential surface of the outer layer (38) to a portion (44A) of the outer circumferential surface of the outer layer (38) closest to the outer circumferential surface of the outer layer (38) in each pullwire lumen (44) and the shortest distance from the outer circumferential surface of the outer layer (38) to a portion (46A) of the outer circumferential surface of the outer layer (38) closest to the outer circumferential surface of the outer layer (38); Catheter shaft (2). [Second item] The inner layer (40) has at least one fluid lumen (48) through which a fluid flows; in at least a portion of the working channel, a shortest distance from a portion (42A) of the outer circumferential surface of the outer layer (38) closest to the outer circumferential surface of the outer layer (38) is longer than a shortest distance from a portion (48A) of the outer circumferential surface of the outer layer (38) closest to the outer circumferential surface of the outer layer (38) in the fluid lumen (48); The catheter shaft (2) described in item 1. [3rd item] A catheter shaft comprising: An outer layer (38); an inner layer (40) covered with an outer layer (38); The inner layer (40) is provided with at least one working channel tube (52) forming a working channel (42) through which a treatment tool is passed, at least four pull wire lumen tubes (62) forming pull wire lumens (44) through which a pull wire (56) is passed, and at least one sensor lumen tube (64) forming a sensor lumen (46) through which at least a portion (18) of a sensor is passed, The working channel tube (52) is eccentric with respect to the axis (C1) of the catheter shaft (2); In at least a portion of the catheter shaft (2), in a cross-sectional view perpendicular to the axis of the catheter shaft (2), each of the pull wire lumen tubes (62) and the sensor lumen tube (64) is in contact with the outer layer (38), and the working channel tube (52) is not in contact with the outer layer (38). Catheter shaft (2). [4th item] The outer layer (38) has a first reinforcing layer (50) on its inner circumferential surface, At least in part, each of the pullwire lumen tubes (62) and the sensor lumen tube (64) contacts the first reinforcement layer (50), and the working channel tube (52) does not contact the first reinforcement layer (50). A catheter shaft (2) as described in item 3. [Item 5] The inner layer (40) is provided with at least one fluid lumen tube (66) that defines a fluid lumen (48) through which a fluid flows; At least in a portion, in cross section, the fluid lumen tube (66) abuts the outer layer (38). A catheter shaft (2) according to item 3 or 4. [Item 6] The outer layer (38) has a first reinforcing layer (50) on its inner circumferential surface, At least a portion of the fluid lumen tube (66) is in contact with the first reinforcing layer (50). A catheter shaft (2) as described in item 5. [Item 7] The inner layer (40) has a second reinforcing layer (54) surrounding the working channel (42). A catheter shaft (2) according to any one of items 1 to 6. [Item 8] When four imaginary lines (L1 to L4) are assumed to connect the axis (C1) of the catheter shaft (2) and the axis (C3) of each pullwire lumen (44) in a cross-sectional view, the difference between the angles (θ1 to θ4) formed by two adjacent imaginary lines (L1 to L4) in the circumferential direction and each of the other angles is 35° or less. A catheter shaft (2) according to any one of items 1 to 7. [Item 9] The fluid lumen (48) also serves as a guidewire lumen through which a guidewire (68) is passed. A catheter shaft (2) according to item 2, 5 or 6. [Item 10] At least a portion of the catheter shaft (2) includes at least a portion of the distal end region (2A); A catheter shaft (2) according to any one of items 1 to 9. [Item 11] A catheter shaft (2) according to any one of items 1 to 10, A handle (4) located on the proximal end side of the catheter shaft (2); A catheter (1) comprising: [Explanation of symbols]

[0065] 1 catheter, 2 catheter shaft, 4 handle, 38 outer layer, 40 inner layer, 42 working channel, 44 pull wire lumen, 46 sensor lumen, 48 fluid lumen, 50 first reinforcing layer, 52 working channel tubing, 54 second reinforcing layer, 62 pull wire lumen tubing, 64 sensor lumen tubing, 66 fluid lumen tubing.

Claims

1. A catheter shaft comprising: An outer layer; an inner layer covered by the outer layer; The inner layer is provided with at least one working channel through which a treatment tool is passed, at least four pull wire lumens through which pull wires are passed, and at least one sensor lumen through which at least a portion of a sensor is passed; the working channel is eccentric with respect to an axis of the catheter shaft; in at least a portion of the catheter shaft, in a cross-sectional view perpendicular to an axis of the catheter shaft, a shortest distance from an outer circumferential surface of the outer layer to a portion of the working channel closest to the outer circumferential surface of the outer layer is longer than a shortest distance from an outer circumferential surface of the outer layer to a portion of each pullwire lumen closest to the outer circumferential surface of the outer layer and a shortest distance from an outer circumferential surface of the outer layer to a portion of the sensor lumen closest to the outer circumferential surface of the outer layer; The inner layer is provided with a working channel tube forming the working channel, a pull wire lumen tube forming each pull wire lumen, and a sensor lumen tube forming the sensor lumen; the working channel tube is eccentric with respect to an axis of the catheter shaft; In at least a portion of the catheter shaft, in the cross-sectional view, each of the pull wire lumen tubes and the sensor lumen tube is in contact with the outer layer, and the working channel tube is not in contact with the outer layer. Catheter shaft.

2. The inner layer has at least one fluid lumen through which a fluid flows; In at least the portion, in the cross-sectional view, a shortest distance from a portion of the working channel closest to the outer circumferential surface of the outer layer to the outer circumferential surface of the outer layer is longer than a shortest distance from a portion of the fluid lumen closest to the outer circumferential surface of the outer layer to the outer circumferential surface of the outer layer. The catheter shaft of claim 1.

3. The outer layer has a first reinforcing layer on an inner circumferential surface, In at least one of the portions, each of the pull wire lumen tubes and the sensor lumen tube contacts the first reinforcement layer, and the working channel tube does not contact the first reinforcement layer. The catheter shaft of claim 1.

4. The inner layer is provided with a fluid lumen tube that forms the fluid lumen, In at least the portion, in the cross-sectional view, the fluid lumen tube is in contact with the outer layer. The catheter shaft of claim 2.

5. The outer layer has a first reinforcing layer on an inner circumferential surface, In at least a portion of the fluid lumen tube, the fluid lumen tube is in contact with the first reinforcing layer. The catheter shaft of claim 4.

6. The inner layer includes a second reinforcing layer surrounding the working channel. The catheter shaft according to any one of claims 1 to 5.

7. When four imaginary lines are assumed to connect the axis of the catheter shaft and the axis of each pull wire lumen in the cross-sectional view, the difference between each angle between two adjacent imaginary lines in the circumferential direction and each of the other angles is 35° or less. The catheter shaft according to any one of claims 1 to 5.

8. The fluid lumen also serves as a guidewire lumen through which a guidewire is passed. The catheter shaft according to claim 2 or 4.

9. the at least a portion including at least a portion of a distal region of the catheter shaft. The catheter shaft according to any one of claims 1 to 5.

10. A catheter shaft according to any one of claims 1 to 5; a handle located on a proximal end side of the catheter shaft; A catheter comprising:

Images