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 a catheter shaft and a catheter.

Background Art

[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

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventors have intensively studied a catheter shaft having a working channel through which a treatment tool such as forceps is passed, a sensor including a camera, and a plurality of lumens through which a pull wire or the like is passed. As a result, they conceived a shaft structure that can improve the ease of insertion and removal of the treatment tool into and from the working channel.

[0005] The present disclosure has been made in view of such circumstances, and an object thereof is to provide a technique for improving the ease of insertion and removal of a treatment tool into and from a working channel.

Means for Solving the Problems

[0006] One 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 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 part of a sensor is passed. The working channel 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, the shortest distance from the outer peripheral surface of the outer layer to the portion closest to the outer peripheral surface of the outer layer in the working channel is longer than the shortest distance from the outer peripheral surface of the outer layer to the portion closest to the outer peripheral surface of the outer layer in each pull wire lumen and the shortest distance from the outer peripheral surface of the outer layer to the portion closest to the outer peripheral surface of the outer layer in the sensor lumen.

[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 is provided with at least one working channel tube that forms a working channel through which a treatment tool is passed, at least four pull wire lumen tubes that form pull wire lumens through which pull wires are passed, and at least one sensor lumen tube that forms 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 the 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. The catheter includes the catheter shaft according to 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 those obtained by converting the expressions of the present disclosure among methods, devices, systems, etc. are also valid as aspects of the present disclosure.

Advantages of the Invention

[0010] According to the present disclosure, it is possible to improve the ease of insertion and removal of the treatment tool into and from the working channel.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0012] Hereinafter, the present disclosure will be described with reference to the drawings based on preferred embodiments. The embodiments are illustrative and not restrictive of the present disclosure, and not all features and combinations thereof described in the embodiments are necessarily essential to the present disclosure. The same or equivalent components, members, and processes shown in each drawing are denoted by the same reference numerals, and redundant descriptions are appropriately omitted. Also, the scales and shapes of the respective parts shown in each figure are set for convenience in order to facilitate the explanation, and are not to be construed restrictively unless otherwise specified. Further, when terms such as "first", "second", etc. are used in this specification or claims, unless otherwise specified, these terms do not represent any order or importance, but are for distinguishing one configuration from another. Also, in each drawing, some members that are not important in explaining the embodiments are omitted from the display.

[0013] (Embodiment 1) FIG. 1 is a plan view of a catheter 1 according to Embodiment 1. The catheter 1 can be used for treating biological organs such as bile ducts and pancreatic ducts. The catheter 1 includes a catheter shaft 2, a handle 4, and a 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 proximal end (base end) of the catheter shaft 2. A tip 6 is provided at the distal end (tip end) of the catheter shaft 2. Hereinafter, the tip 6 side of the catheter 1 and each member constituting the catheter 1 will be appropriately referred to as the "tip side", and the handle 4 side will be referred to as the "base end side". Also, the direction in which the axis of the catheter shaft 2 extends is referred to as the "axial direction", the direction orthogonal to the axis is referred to as the "radial direction", and the direction around the axis is 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 within a desired range by, for example, making the hardness (e.g., Shore D hardness) of the resin constituting the catheter shaft 2 different between the tip region 2A and the region on the base end 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 is operated by an operator such as a doctor. As an example, the handle 4 has a grip 8, two operation knobs 10, 12, a working channel port 14, a sensor port 16, and a fluid port (not shown).

[0018] The grip 8 is gripped by the operator. The proximal ends of the two pull wires 56 are attached to the operation knob 10. The proximal 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 proximal 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 proximal 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 proximal 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 proximal end. By pulling the four pull wires 56, the tip region 2A can be bent in multiple directions. Since the technique of bending the tip region 2A using the pull wires 56 is well-known, further detailed description is omitted.

[0019] The working channel port 14 communicates with the working channel 42. The operator can insert and remove the treatment instrument into and from the working channel 42 through the working channel port 14. The sensor port 16 communicates with the sensor lumen 46. The 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 communicates with the fluid lumen 48.

[0020] The tip chip 6 is inserted into the tip of the catheter shaft 2. By inserting the tip side of the catheter shaft 2 into the body, the tip chip 6 is fed into the treatment site in the body. FIGS. 2 and 3 are perspective views of the tip of the catheter 1. In FIGS. 2 and 3, a state in which a portion overlapping the tip chip 6 of the outer layer 38 is cut out is shown. Also, in FIG. 3, the pull wire 56 is not shown.

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

[0022] The tip chip 6 has a sensor groove 24 at the tip. A sensor lumen 46 communicates with the bottom of the sensor groove 24. The catheter 1 of the present 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 proximal side of the outer peripheral surface. Each pull wire groove 30 has a narrow portion 32 extending axially from the proximal 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 proximal end of the narrow portion 32 communicates with the pull wire lumen 44. A pull wire 56 is fitted into the pull wire groove 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 proximal side by the operation of the operation knobs 10 and 12, the large diameter portion 60 is caught by the step between the wide portion 34 and the narrow portion 32, and the displacement toward the proximal side is restricted. Thereby, the distal region 2A can 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 side to the proximal side. The proximal side of one of the second through holes 36 communicates with one of the fluid lumens 48. The proximal side of the other second through hole 36 communicates with the other fluid lumen 48. In addition, the proximal side portion of the second through hole 36 of the present embodiment is exposed on the outer peripheral surface of the distal tip 6. That is, the proximal side portion of the second through hole 36 is in a groove shape.

[0025] Subsequently, 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 Embodiment 1. FIG. 5(A) is a cross-sectional view taken along line A-A of FIG. 4. FIG. 5(B) is a cross-sectional view taken along line B-B of 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. In addition, in FIGS. 5(A) and 5(B), the illustration of the cable 18 and the pull wire 56 is omitted.

[0026] The catheter shaft 2 includes an outer layer 38 and an inner layer 40 covered by the outer layer 38. Further, the inner layer 40 is provided with one working channel 42, four pull wire lumens 44, one sensor lumen 46, and two fluid lumens 48. These channels and lumens are enclosed within the inner layer 40 and are separated from each other 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 within the outer layer 38. The tip of the inner layer 40 is located on the proximal end side of the catheter shaft 2 relative to the tip of the outer layer 38. The tip chip 6 is inserted into the recessed portion of the inner layer 40 at the tip of the catheter shaft 2.

[0028] Examples of the material for the outer layer 38 include synthetic resins having good lubricity, mechanical strength, flexibility, and biocompatibility such as polyether block amide (PEBAX). Examples of the material for the inner layer 40 include synthetic resins such as polyolefin, polyamide, polyether block amide, polyurethane, nylon, and polyester. Contrast agents, pigments, etc. may be kneaded into the constituent materials of the outer layer 38 and the inner layer 40. 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 there may be cases where the inner layer 40 has a higher hardness than the outer layer 38, and there may also be cases where the inner layer 40 and the outer layer 38 have the same hardness.

[0029] The outer layer 38 has a first reinforcing layer 50 on its inner peripheral surface. In the present 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 wire strands are wound in a spiral shape. Note that the first reinforcing layer 50 may be composed of a braid in which a plurality of wire strands are woven into a cylindrical shape. Examples of the material of the wire strands include biocompatible metals such as tungsten, stainless steel, and nickel-titanium, and biocompatible materials such as nylon, polyether ketone (PEEK), and liquid crystal polymer. By having the first reinforcing layer 50 in the outer layer 38, it is possible to easily maintain the shape of the channels and lumens enclosed in the inner layer 40. Note that FIG. 4 schematically shows the first reinforcing layer 50.

[0030] The working channel 42 is a tube extending from the proximal end to the distal end of the catheter shaft 2, and is a passage for a treatment instrument inserted or withdrawn from the working channel port 14. Examples of the treatment instrument include forceps, cannula, dilator, guide wire, snare, injection needle, high-frequency knife, stent, and the like. Note that there may be two or more working channels 42. The working channel 42 is formed by a working channel tube 52 embedded in the inner layer 40. That is, the inner surface of the working channel tube 52 partitions the working channel 42, and the internal space of the working channel tube 52 serves as the working channel 42.

[0031] The proximal end of the working channel tube 52 communicates with the working channel port 14. The distal end of the working channel tube 52 communicates with the first through hole 22. Examples of the material of the working channel tube 52 include synthetic resins having good lubricity such as polytetrafluoroethylene (PTFE) and perfluoroalkoxy alkane (PFA).

[0032] The inner layer 40 has a second reinforcing layer 54 that surrounds the working channel 42. The inner layer 40 of the present 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. That is, the inner layer 40 is interposed between the second reinforcing layer 54 and the outer layer 38. The second reinforcing layer 54 is composed of, for example, a coil or braid, similar to the first reinforcing layer 50. By having the inner layer 40 with the second reinforcing layer 54, it is possible to easily maintain the shape of the working channel 42. Note that in FIG. 4, the second reinforcing layer 54 is schematically shown.

[0033] The four pull wire lumens 44 are tubes that extend from the proximal end to the distal end of the catheter shaft 2, and the pull wires 56 are passed through and accommodated therein. Note that the number of pull wire lumens 44 should be at least four, but preferably four. Each pull wire lumen 44 is formed by a pull wire lumen tube 62 embedded in the inner layer 40. That is, the inner surface of the pull wire lumen tube 62 partitions the pull wire lumen 44, and the internal space of each pull wire lumen tube 62 serves as the pull wire lumen 44.

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

[0035] The sensor lumen 46 is a tube extending from the proximal end to the distal end of the catheter shaft 2, and at least a part of the sensor is passed through and accommodated therein. In the present embodiment, a cable 18 is passed through the sensor lumen 46 as a part of the sensor. Examples of the cable 18 include a power cable and a signal cable. Note that the sensor itself may be passed through the sensor lumen 46. Examples of the sensor mounted on the catheter 1 include a thermocouple, an ultrasonic sensor, an optical sensor, a pressure sensor, etc. in addition to the camera module 26. Note that there may be two or more sensor lumens 46. 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 proximal end of the sensor lumen tube 64 communicates with the sensor port 16. The distal end 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 proximal end to the distal end of the catheter shaft 2, and are passages through which fluid flows. Examples of the fluid flowing through the fluid lumen 48 include physiological saline supplied to the treatment site and body fluids (blood and tissue fluid) recovered from the treatment site. Note that there may be one, three or more fluid lumens 48, or they may be omitted. Each fluid lumen 48 is formed by a fluid lumen tube 66 embedded in the inner layer 40. That is, the inner surface of the fluid lumen tube 66 defines the fluid lumen 48, and the internal space of each fluid lumen tube 66 becomes the fluid lumen 48.

[0038] The proximal end of each fluid lumen tube 66 communicates with a fluid port. The distal end of each fluid lumen tube 66 communicates with the second through hole 36. By discharging the physiological saline sent to the distal end side of the catheter shaft 2 through the fluid lumen 48 from the second through hole 36, the treatment site can be washed. Also, by sucking the body fluid accumulated at the treatment site from the second through hole 36 and collecting it to the proximal end side of the catheter shaft 2 through the fluid lumen 48, the treatment site can be washed. Thus, the visual field of the camera module 26, and thus the visual field of the operator, can be ensured. The material of the fluid lumen tube 66 is the same as, for example, that of the working channel tube 52.

[0039] Subsequently, the arrangement of the channels and lumens enclosed 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. That is, the axis C2 of the working channel 42 and the working channel tube 52 is displaced with respect to the axis C1 of the catheter shaft 2. Note that the axis C1 of the catheter shaft 2 is substantially equal to the axis of the outer layer 38.

[0040] Also, 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 closest to the outer peripheral surface of the outer layer 38 in the working channel 42 is greater than the shortest distance from the outer peripheral surface of the outer layer 38 to the portion 44A closest to the outer peripheral surface of the outer layer 38 in each pull wire lumen 44, the shortest distance from the outer peripheral surface of the outer layer 38 to the portion 46A closest to the outer peripheral surface of the outer layer 38 in the sensor lumen 46, and the shortest distance from the outer peripheral surface of the outer layer 38 to the portion 48A closest to the outer peripheral surface of the outer layer 38 in the fluid lumen 48. That is, although the axis C2 of the working channel 42 is displaced with respect to the axis C1 of the catheter shaft 2, it is closer to the axis C1 than the axes of the pull wire lumen 44, the sensor lumen 46, and the fluid lumen 48. Even when there are two or more working channels 42, five or more pull wire lumens 44, two or more sensor lumens 46, or one, three or more fluid lumens 48, each channel and each lumen are arranged so that the above-described positional relationship is satisfied.

[0041] Also, in a cross-sectional view perpendicular to the axis of the catheter shaft 2, each pull wire lumen tube 62, sensor lumen tube 64, and fluid lumen tube 66 are in contact with the outer layer 38, and the working channel tube 52 is not in contact with the outer layer 38. Note that the outer layer 38 of the present embodiment has a first reinforcing layer 50 on the surface facing the inner layer 40 side. Therefore, each pull wire lumen tube 62, sensor lumen tube 64, and fluid lumen tube 66 are in contact with the first reinforcing layer 50, and the working channel tube 52 is not in contact with the first reinforcing layer 50. That is, although the axis C2 of the working channel tube 52 is displaced with respect to 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, sensor lumen tube 64, and 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 no inner layer 40 is interposed between the tube and the outer layer 38 or the first reinforcing layer 50. Further, "the tube is non-contact with the outer layer 38 or the first reinforcing layer 50" means that an inner layer 40 is interposed between the tube and the outer layer 38 or the first reinforcing layer 50. Note that in 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 together. In this embodiment, the portion where the resin components of both layers are mixed at the boundary between the outer layer 38 and the inner layer 40 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 with a thin thickness of the inner layer 40 interposed between the working channel 42 and the outer layer 38 is likely to be formed. As a result of intensive studies by the present inventors, it has been found that when there is a thin-walled portion, wrinkles may form on the side wall of the working channel 42 or the formed wrinkles may become larger when the catheter shaft 2 is bent or the like. In particular, when the thickness of the thin-walled portion is less than 0.28 mm, the tendency to form wrinkles is enhanced, and as the thickness becomes thinner, the formed wrinkles become larger, and it has been confirmed that the formed wrinkles become significantly larger when the thickness is 0.1 mm or less. When the wrinkles generated in the working channel 42 become large, it becomes difficult to insert and remove the treatment instrument, and the operability of the treatment instrument may be reduced. This problem was first discovered by the present inventors and should not be regarded as a general recognition of those skilled in the art.

[0044] As a countermeasure against such a problem, by arranging the working channel 42 as described above, it is possible to suppress the formation of a thin-walled portion around the working channel 42 and suppress the generation of wrinkles. Alternatively, it is possible to suppress the increase in the size of the formed wrinkles. As a result, the ease of insertion and removal of the treatment instrument with respect to the working channel 42 can be improved. Further, thereby, the workability of the procedure using the catheter 1 can be enhanced.

[0045] Further, 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 an installation space for the second reinforcing layer 54. And by providing the second reinforcing layer 54, the generation or enlargement of wrinkles can be further suppressed. Also, 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 instrument to enter the viewing angle of the camera module 26. Thereby, the treatment instrument can be made easier to operate. In the description regarding the generation or enlargement of the above-described wrinkles and the suppression of the generation or enlargement, the working channel 42 can also be read as the working channel tube 52.

[0046] In the present embodiment, the camera head 28 is fixed to the tip chip 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, for example, for the purpose of reusing the camera module 26 or the like, the diameter of the sensor lumen 46 can be made smaller compared to the case where the entire camera module 26 is inserted into the sensor lumen 46. Thereby, it becomes 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] Also, in a cross-sectional view orthogonal to the axis of the catheter shaft 2, the working channel 42, the pull wire lumen 44, and the sensor lumen 46 have an approximately circular shape, while the fluid lumen 48 has an elongated hole shape. Thereby, while suppressing the arrangement design of 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 from being inhibited by the fluid lumen 48, the cross-sectional area of the fluid lumen 48 can be increased to easily secure the flow rate of the fluid.

[0048] Also, by bringing the axial center C2 of the working channel 42 and the working channel tube 52 closer to the axial center C1 of the catheter shaft 2, it becomes easier to evenly arrange the four pull wire lumens 44 in the circumferential direction of the catheter shaft 2. FIG. 6 is a diagram for explaining the arrangement of the pull wire lumens 44. In FIG. 6, the illustration of the cable 18 and the pull wire 56 is omitted. In the present embodiment, when assuming four virtual lines connecting the axial center C1 of the catheter shaft 2 and the axial center C3 of each pull wire lumen in a cross-sectional view orthogonal to the axis of the catheter shaft 2, the angle formed by two adjacent virtual lines in the circumferential direction preferably has a difference of 35° or less, more preferably 30° or less, and even more preferably 25° or less from the other angles.

[0049] Specifically, a virtual line connecting the axial center C1 and the axial center C3 of the pull wire lumen 44 located in the upper left in FIG. 6 is defined as the virtual line L1. Also, a virtual line connecting the axial center C1 and the axial center C3 of the pull wire lumen 44 located in the upper right in FIG. 6 is defined as the virtual line L2. Also, a virtual line connecting the axial center C1 and the axial center C3 of the pull wire lumen 44 located in the lower right in FIG. 6 is defined as the virtual line L3. Also, a virtual line connecting the axial center C1 and the axial center C3 of the pull wire lumen 44 located in the lower left in FIG. 6 is defined as the virtual line L4. Also, the angle formed by the virtual line L1 and the virtual line L2 is defined as the angle θ1. Also, the angle formed by the virtual line L2 and the virtual line L3 is defined as the angle θ2. Also, the angle formed by the virtual line L3 and the virtual line L4 is defined as the angle θ3. Also, the angle formed by the virtual line L4 and the virtual line L1 is defined as the angle θ4. At this time, the differences between the angles θ1 to θ4 and the other angles are each 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 differences between the angles θ1 to θ4 can be made substantially zero. Also, 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 differences between the angles θ1 to θ4 can be made 15° or less.

[0051] With such an arrangement of the pull wire lumens 44, it is possible to suppress differences in the degree of bending of the tip region 2A and the operating feel of the operation knobs 10 and 12 depending on the direction of bending the tip region 2A. Thereby, the operability of the catheter 1 can be improved. The four pull wire lumens 44 are arranged at approximately equal distances from the axis C1 of the catheter shaft 2. For example, in a cross-sectional view orthogonal to the axis of the catheter shaft 2, the difference in the distance from the axis C1 to the axis C3 of each pull wire lumen 44 is 15% or less with respect to the radius of the catheter shaft 2.

[0052] The above-described arrangement of the channels and each lumen, as well as the arrangement of each tube, only needs to be satisfied in at least a part of the catheter shaft 2 in the axial direction of the catheter shaft 2, but it is preferably satisfied in at least a part of the tip region 2A, more preferably satisfied in a region including the apex of the curvature in the tip region 2A, and even more preferably 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 an example of the manufacturing method of the catheter shaft 2, first, a working channel tube 52, a pull wire lumen tube 62, a sensor lumen tube 64, and a fluid lumen tube 66, which are arranged on the outer periphery of a mandrel, are prepared. At this time, each tube prepared in advance may be put on the mandrel, or each tube may be formed on the outer periphery of the mandrel by extrusion molding.

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

[0055] (Embodiment 2) The catheter 1 according to the present embodiment is generally common in configuration with the catheter 1 according to Embodiment 1, except that the fluid lumen 48 has additional functions. Hereinafter, the catheter 1 according to Embodiment 2 will be described centering on the configuration different from that of Embodiment 1, and the common configuration will be briefly described or the description will be omitted.

[0056] FIG. 7 is a cross-sectional view of the catheter shaft 2 according to Embodiment 2. FIG. 7 shows a cross-section orthogonal to the axis of the catheter shaft 2. In FIG. 7, the illustration of the cable 18 and the pull wire 56 is omitted.

[0057] Also in the catheter shaft 2 according to the present embodiment, in a cross-sectional view orthogonal 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 closest to the outer peripheral surface of the outer layer 38 in the working channel 42 is the shortest distance from the outer peripheral surface of the outer layer 38 to the portion 44A closest to the outer peripheral surface of the outer layer 38 in each pull wire lumen 44, the shortest distance from the outer peripheral surface of the outer layer 38 to the portion 46A closest to the outer peripheral surface of the outer layer 38 in the sensor lumen 46, and the shortest distance from the outer peripheral surface of the outer layer 38 to the portion 48A closest to the outer peripheral surface of the outer layer 38 in the fluid lumen 48 (see FIG. 4).

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

[0059] Also, the fluid lumen 48 of the present embodiment also serves as a guide wire lumen through which the guide wire 68 passes. When the catheter shaft 2 does not have a guide wire lumen, the guide wire 68 will be passed through the working channel 42. However, if the guide wire 68 and the treatment instrument are simultaneously passed through the working channel 42, the guide wire 68 may interfere with the insertion, extraction, and operation of the treatment instrument, so it is desirable to avoid simultaneous insertion. For this reason, the guide wire 68 passed through the working channel 42 needs to be pulled out once to pass the treatment instrument, or vice versa. As a result, the workability of the procedure using the catheter 1 may be reduced.

[0060] On the other hand, for the fluid and the guide wire 68, even if they are simultaneously passed through the fluid lumen 48, they do not interfere with each other or the degree of interference is low. For this reason, the fluid lumen 48 can be used as a guide wire lumen. And by using the fluid lumen 48 as a guide wire lumen, the workability of the procedure using the catheter 1 can be improved.

[0061] The fluid lumen 48 of the present embodiment generally has an approximately circular shape in a cross-sectional view perpendicular to the axis of the catheter shaft 2. The guide wire 68 generally has an approximately circular cross-sectional shape. For this reason, by making the cross-section of the fluid lumen 48 approximately circular, it is easier to avoid the guide wire 68 contacting the side wall of the fluid lumen 48 compared to the case where the cross-section is a long hole shape as in Embodiment 1.

[0062] Even when the cross-section of the fluid lumen 48 is approximately circular, the difference between the angles θ1 to θ4 formed by the virtual lines L1 to L4 can be set to 35° or less. For example, when the diameter of the catheter shaft 2 is 3.8 mm, the diameter of the 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 the angles θ1 to θ4 can be set to 32° or less.

[0063] As described above, the embodiments of the present disclosure have been described in detail. The above-described embodiments are merely specific examples for implementing the present disclosure. The content of the embodiments does not limit the technical scope of the present disclosure, and many design changes such as component changes, additions, deletions, etc. are possible without departing from the idea of the present disclosure defined in the claims. The new embodiments to which design changes are applied have the combined effects of the combined embodiments and the modifications. In the above-described embodiments, with respect to the content in which such design changes are possible, notations such as "in the present embodiment" and "in the present embodiment" are added and emphasized, but design changes are also allowed for the content without such notations. Any combination of the components included in each embodiment is also valid as an aspect of the present disclosure. The hatching attached to the cross-section of the drawing does not limit the material of the object to which the hatching is attached.

[0064] The embodiment may be specified by the items described below. [Item 1] A catheter shaft (2), An outer layer (38), An inner layer (40) covered by the outer layer (38), and The inner layer (40) is provided with at least one working channel (42) through which a treatment instrument is passed, at least four pull wire lumens (44) through which a pull wire (56) is passed, and at least one sensor lumen (46) through which at least a part (18) of a sensor is passed. The working channel (42) is eccentric with respect to the axis (C1) of the catheter shaft (2). In at least a part 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 peripheral surface of the outer layer (38) to the portion (42A) closest to the outer peripheral surface of the outer layer (38) in the working channel (42) is longer than the shortest distance from the outer peripheral surface of the outer layer (38) to the portion (44A) closest to the outer peripheral surface of the outer layer (38) in each pull wire lumen (44) and the shortest distance from the outer peripheral surface of the outer layer (38) to the portion (46A) closest to the outer peripheral surface of the outer layer (38) in the sensor lumen (46). Catheter shaft (2). [Item 2] The inner layer (40) is provided with at least one fluid lumen (48) through which fluid flows. In at least a part, in a cross-sectional view, the shortest distance from the outer peripheral surface of the outer layer (38) to the portion (42A) closest to the outer peripheral surface of the outer layer (38) in the working channel (42) is longer than the shortest distance from the outer peripheral surface of the outer layer (38) to the portion (48A) closest to the outer peripheral surface of the outer layer (38) in the fluid lumen (48). The catheter shaft (2) according to Item 1. [Item 3] A catheter shaft, an outer layer (38), and an inner layer (40) covered by the outer layer (38), The inner layer (40) is provided with at least one working channel tube (52) that forms a working channel (42) through which a treatment tool is passed, at least four pull wire lumen tubes (62) that form a pull wire lumen (44) through which a pull wire (56) is passed, and at least one sensor lumen tube (64) that forms a sensor lumen (46) through which at least a part (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 part of the catheter shaft (2), in a cross-sectional view perpendicular to the axis of the catheter shaft (2), each pull wire lumen tube (62) and the sensor lumen tube (64) are 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). [Item 4] The outer layer (38) has a first reinforcing layer (50) on its inner peripheral surface. In at least a part, each pull wire lumen tube (62) and the sensor lumen tube (64) are in contact with the first reinforcing layer (50), and the working channel tube (52) is not in contact with the first reinforcing layer (50). The catheter shaft (2) according to Item 3. [Item 5] The inner layer (40) is provided with at least one fluid lumen tube (66) that forms a fluid lumen (48) through which fluid flows. In at least a part, in a cross-sectional view, the fluid lumen tube (66) is in contact with the outer layer (38). The catheter shaft (2) according to Item 3 or Item 4. [Item 6] The outer layer (38) has a first reinforcing layer (50) on its inner peripheral surface. In at least a part, the fluid lumen tube (66) is in contact with the first reinforcing layer (50). The catheter shaft (2) according to Item 5. [Item 7] The inner layer (40) has a second reinforcing layer (54) that surrounds the working channel (42). The catheter shaft (2) according to any one of Items 1 to 6. [Item 8] When assuming four virtual lines (L1 to L4) connecting the axis (C1) of the catheter shaft (2) and the axis (C3) of each pull wire lumen (44) in a cross-sectional view, the angles (θ1 to θ4) formed by two adjacent virtual lines (L1 to L4) in the circumferential direction each have a difference of 35° or less from the other angles. The catheter shaft (2) according to any one of Items 1 to 7. [Item 9] The fluid lumen (48) also serves as a guide wire lumen through which a guide wire (68) is passed. The catheter shaft (2) according to Item 2, Item 5 or Item 6. [Item 10] At least a part thereof includes at least a part of the distal region (2A) of the catheter shaft (2). The catheter shaft (2) according to any one of Items 1 to 9. [Item 11] The catheter shaft (2) according to any one of Items 1 to 10, a handle (4) located on the proximal side of the catheter shaft (2), and a catheter (1) comprising the same.

Description of Reference Numerals

[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 tube, 54 Second reinforcing layer, 62 Pull wire lumen tube, 64 Sensor lumen tube, 66 Fluid lumen tube.

Claims

1. It is a catheter shaft, The outer layer, The system comprises an inner layer covered by the outer layer, The inner layer is provided with at least one working channel through which a treatment instrument is passed, and at least four pull wire lumens through which a pull wire 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 surface of the outer layer to the portion of the working channel closest to the outer surface of the outer layer is longer than the shortest distance from the outer surface of the outer layer to the portion of each pull wire lumen closest to the outer surface of the outer layer, and when four imaginary lines are assumed to connect the axis of the catheter shaft and the axis of each pull wire lumen, the angle between two adjacent imaginary lines in the circumferential direction of the catheter shaft is 35° or less in difference from the other angles. Catheter shaft.

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

3. The outer layer has a first reinforcing layer on its inner circumferential surface. In at least a portion of the above, the pull wire lumen tubes forming each pull wire lumen are in contact with the first reinforcing layer, and the working channel tubes forming the working channel are not in contact with the first reinforcing layer. The catheter shaft according to claim 1.

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

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

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

7. The shortest distance from the outer surface of the outer layer to the portion of the working channel closest to the outer surface of the outer layer is 0.28 mm or more. A catheter shaft according to any one of claims 1 to 5.

8. The aforementioned fluid lumen also serves as the guide wire lumen through which the guide wire passes. The catheter shaft according to claim 2 or 4.

9. The aforementioned at least part includes at least a portion of the tip region of the catheter shaft, A 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 at the proximal end of the catheter shaft, A catheter equipped with [a specific feature / equipment].

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