catheter

Abstract

Provided is a catheter that, when a distal portion of the catheter is to be bent, can easily achieve a desired bent shape by preventing twisting and kinking in the bending of the distal portion of the catheter, while preventing interference of a tubular member with a wire serving as a traction member and a plate spring serving as a bending member.　A catheter (1) has: a shaft (2); a coil (50); a plate spring (40) having a first connecting section (41) a proximal end of which is connected to a distal end of the coil (50); at least one wire (30); and a tubular member (60) that is disposed outside the coil (50) such that the wire (30), the plate spring (40), and the first connecting section (41) are arranged in a lumen. The tubular member (60) has a first section (S1) extending from the distal end of the coil (50) to a point -D of length d on a proximal side. In the first section (S1), a lumen wall of the tubular member (60) is not in contact with the outer side surface of the coil (50), and the length d is a length of at least one winding, and no more than thirty windings, of the coil (50).

Description

[Technical Field]

[0001] The present invention relates to a catheter whose distal portion is flexible. [Background technology]

[0002] In the examination and treatment of heart disease, catheters are used, which are inserted into the heart through an artery. To deliver the catheter tip to the desired location within the heart, the distal end of the catheter needs to be curved to follow the blood vessels within the heart. Therefore, catheters have been devised that allow the distal end to be bent by operating a handle located on the proximal end. Generally, these bendable catheters allow the distal end to be bent by pulling a wire fixed inside the catheter tip via a handle.

[0003] One proposed catheter features a design in which the distal end of a leaf spring, which is a component that bends the distal portion of the catheter, and the distal end of a wire are fixed to the distal end of the catheter, and the proximal end of the leaf spring is connected to a tube placed inside the lumen of the catheter.

[0004] Incidentally, in order to deliver the tip of the catheter to the desired site according to the size of the heart and the purpose, the distal portion of the catheter must have the ability to be freely bent in the desired direction by wire manipulation and to follow the winding blood vessels (trackability). Furthermore, in order to prevent the distal portion of the catheter from advancing in an undesirable direction and damaging the lumen wall of the body, and to improve the ability to transmit force from the proximal side to the distal portion of the catheter (pusherability), it is necessary to suppress problems such as twisting and kinking of the distal portion of the catheter when it bends. For this reason, various forms have been proposed for fixing the proximal side of the leaf spring, which is positioned at the distal portion of the catheter and is a component that bends the distal portion of the catheter.

[0005] In the catheters disclosed in Patent Documents 1 and 2, a wire is disposed within a wire tube, and a leaf spring is disposed within a catheter tube with its proximal end fixed to a coil tube. Among these, in the catheter disclosed in Patent Document 2, a wire tube is fixed to the surface of the leaf spring via an adhesive layer. Patent Document 3 discloses a catheter in which a leaf spring is fixed to a coil tube via a coil stopper. In the catheter disclosed in Patent Document 4, a wire and a leaf spring are disposed within a distal tube, and the proximal end of the leaf spring is fixed to a proximal tube. Further, a protective tube is disposed outside the proximal tube, and it is disclosed that the proximal end of the distal tube is more distal than the distal end of the protective tube.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in conventional catheters, if a coil is attached to the proximal end of a leaf spring to ensure rigidity at the base of the curve, the coil is compressed by the wire's tension, deforming to expand radially, causing the leaf spring connected to the coil to rotate, resulting in a problem where the distal end of the catheter twists and curves. To prevent this, the connection between the coil and the leaf spring can be fixed to the catheter tube, but since the rigidity of the fixed part increases, a rigidity step occurs in the longitudinal axis direction of the catheter tube, where the stiffness changes abruptly. As a result, when the distal end of the catheter is curved, a kink may occur where the distal end of the catheter breaks at the point where the rigidity step occurs, indicating room for improvement. Furthermore, there was room for improvement in the fact that the wire, which is the tensioning member, and the leaf spring, which is the bending member, are interfered with by other members, negatively affecting the curved shape of the distal end of the catheter.

[0008] Interference of other components with the traction member or bending member when bending the distal portion of the catheter, as well as twisting or kinking of the distal portion of the catheter, can lead to a decrease in pushability, potentially resulting in a catheter with reduced trackability because the desired curved shape cannot be obtained. The present invention has been made in view of the above, and its purpose is to provide a catheter that can easily achieve the desired curved shape by preventing interference of the cylindrical member with the wire, which is the traction member, and the leaf spring, which is the bending member, when bending the distal portion of the catheter, while also preventing twisting and kinking of the curved portion of the catheter. [Means for solving the problem]

[0009] A catheter that has solved the above problems comprises a shaft having a distal end and a proximal end in the longitudinal direction and a lumen extending in the longitudinal direction; a coil having a lumen extending in the longitudinal direction and positioned in the lumen of the shaft; a leaf spring extending in the lumen of the shaft, having a first connection part in which the proximal end of the leaf spring is directly or indirectly connected to the distal end of the coil, and a second connection part in which the distal end of the leaf spring is directly or indirectly fixed to the distal end of the shaft; and a component extending in the lumen of the coil, with its distal end directly or indirectly connected to the distal end of the shaft. The catheter comprises one or more wires indirectly connected, and a cylindrical member having a lumen extending in the longitudinal direction, wherein the wire, leaf spring, and first connection portion are arranged in the lumen of the cylindrical member and the cylindrical member is positioned outside the coil. In the longitudinal direction, the cylindrical member has a first section from the distal end of the coil to point D with length d proximally, and a second section from point D to the proximal end of the cylindrical member. In the first section, the lumen wall of the cylindrical member does not abut the outer surface of the coil, and the length d is between 1 turn and 30 turns of the coil. With this configuration, interference of the cylindrical member with the wire used to pull the distal end of the catheter and with the leaf spring that determines the curved shape of the distal end of the catheter can be prevented when the distal end of the catheter is curved. As a result, the force from the proximal side is easily transmitted to the wire located in the distal end of the catheter, and the curvature of the leaf spring accompanying the pulling of the wire is less affected by the cylindrical member, resulting in a catheter that is less prone to kinking. Furthermore, even if the coil is compressed due to wire traction, deformation that causes it to expand radially can be prevented, and twisting of the distal end of the catheter curve due to the rotation of the leaf spring connected to the coil can be suppressed. Since the ease with which the coil expands depends on the number of turns in the coil, the above effect can be achieved by ensuring that the length of the first section in the longitudinal axis direction is less than or equal to a predetermined number of turns in the coil. In addition, since it is possible to prevent the occurrence of rigidity steps in the longitudinal axis direction of the distal end of the catheter, kinking of the distal end of the catheter can be prevented. As a result, it becomes easier to achieve the desired curved shape of the distal end of the catheter.

[0010] In the second section, it is preferable that at least a portion of the inner wall of the cylindrical member is in contact with the outer surface of the coil.

[0011] In the longitudinal axis direction, it is preferable that the first connecting portion is located in the first section.

[0012] Preferably, the cylindrical member extends to the second connection point, and the leaf spring and wire are arranged inside the lumen of the cylindrical member at the distal end of the shaft.

[0013] In the longitudinal axis direction, the proximal end of the cylindrical member is preferably located distal to the proximal end of the coil, and the coil has a first fixing portion that is fixed to the shaft proximal to the proximal end of the cylindrical member. In this case, in the longitudinal axis direction, the length from the distal end of the first fixing portion to the proximal end of the cylindrical member is preferably 20 turns or less of the coil.

[0014] The cylindrical member preferably has a second fixing portion fixed to the shaft in the second section. In this case, in the longitudinal axis direction, the length from the distal end of the second fixing portion to the distal end of the coil is preferably twice the length of the leaf spring or less. Furthermore, in this case, in the longitudinal axis direction, the distal end of the second fixing portion is located proximal to the proximal end of the first connecting portion, and the length from the distal end of the second fixing portion to the proximal end of the first connecting portion is preferably 1 / 4 or more the length of the leaf spring. [Effects of the Invention]

[0015] According to the present invention, in a catheter with a bendable distal portion, interference of the tubular member with the wire or leaf spring can be prevented when bending the distal portion of the catheter. This allows force from the proximal end to be easily transmitted to the wire located in the distal portion of the catheter, and the bending of the leaf spring due to wire traction is less affected by the tubular member, resulting in a catheter. Furthermore, twisting and kinking of the distal portion of the catheter can be prevented. As a result, it is possible to provide a catheter in which the desired curved shape of the distal portion of the catheter can be achieved by wire manipulation, and the distal portion of the catheter can be easily delivered to a desired position. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 shows a plan view of a catheter according to one embodiment of the present invention. [Figure 2] Figure 2 shows a cross-sectional view (partially a plan view) of the distal portion of the catheter shown in Figure 1, along the longitudinal axis. [Figure 3] Figure 3 shows a cross-sectional view of the catheter along the line III-III in Figure 2. [Figure 4] Figure 4 shows a cross-sectional view of the catheter along the IV-IV line in Figure 2. [Figure 5] Figure 5 shows a cross-sectional view of the catheter along the VV line in Figure 2. [Figure 6] Figure 6 shows a cross-sectional view of the catheter along the line VI-VI in Figure 2. [Figure 7] Figure 7 shows a plan view of a coil according to one embodiment of the present invention. [Figure 8] Figure 8 shows a plan view of the coil shown in Figure 7 at its maximum compression. [Figure 9] Figure 9 shows a cross-sectional view (partially a plan view) of the distal portion of a catheter according to another embodiment of the present invention, in the longitudinal direction. [Figure 10] Figure 10 shows a cross-sectional view (partially a plan view) of the distal portion of a catheter according to yet another embodiment of the present invention, in the longitudinal direction. [Figure 11] Figure 11 shows a cross-sectional view of the catheter along the line XI-XI in Figure 10. [Figure 12] Figure 12 shows another example of the cross-sectional view shown in Figure 11. [Figure 13] Figure 13 shows a cross-sectional view (partially a plan view) of the distal portion of a catheter according to yet another embodiment of the present invention, in the longitudinal direction. [Figure 14] Figure 14 shows a cross-sectional view of the catheter along the line XIV-XIV in Figure 13. [Figure 15] Figure 15 shows another example of the cross-sectional view shown in Figure 14. [Modes for carrying out the invention]

[0017] The present invention will be described below based on embodiments, but the present invention is not limited by the embodiments described below, and it is certainly possible to implement it with appropriate modifications within the scope that is consistent with the spirit of the preceding and following descriptions, and all such modifications are included within the technical scope of the present invention. In addition, hatching and component reference numerals may be omitted in the drawings for convenience, in which case refer to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, as priority is given to helping to understand the features of the present invention.

[0018] A catheter according to an embodiment of the present invention comprises a shaft having a distal end and a proximal end in the longitudinal direction and a lumen extending in the longitudinal direction; a coil having a lumen extending in the longitudinal direction and disposed within the lumen of the shaft; a leaf spring extending within the lumen of the shaft, having a first connection portion in which the proximal end of the leaf spring is directly or indirectly connected to the distal end of the coil, and a second connection portion in which the distal end of the leaf spring is directly or indirectly fixed to the distal end of the shaft; and a component extending within the lumen of the coil, with its distal end directly connected to the distal end of the shaft. Alternatively, the coil comprises one or more wires indirectly connected, and a cylindrical member having a lumen extending in the longitudinal direction, wherein the wires, leaf springs, and the first connecting portion are arranged in the lumen of the cylindrical member and the cylindrical member is positioned outside the coil, and in the longitudinal direction, the cylindrical member has a first section from the distal end of the coil to a point D of length d proximally, and a second section from point D to the proximal end of the cylindrical member, the lumen wall of the cylindrical member not in contact with the outer surface of the coil in the first section, and the length d is between 1 turn and 30 turns of the coil.

[0019] Having the above configuration, the catheter according to the embodiment of the present invention can bend the distal portion of the catheter distal to the coil by bending a leaf spring connected to the distal end of the shaft through the tension of a wire, while ensuring rigidity at the proximal end of the distal end of the catheter with the coil. From the viewpoint of operation, the wire can be called the traction member and the leaf spring can be called the bending member. In the first section, since the inner wall of the cylindrical member does not come into contact with the outer surface of the coil, interference of the cylindrical member with the wire, which is the traction member, and the leaf spring, which is the bending member, can be prevented. As a result, the force from the proximal end is easily transmitted to the wire located in the distal portion of the catheter, and the bending of the leaf spring accompanying the traction of the wire is less affected by the cylindrical member, resulting in a catheter. Furthermore, since a cylindrical member is positioned on the outside of the coil, and the length in the longitudinal direction of the first section where the inner wall of the cylindrical member does not contact the outer surface of the coil is 30 turns or less of the coil, the cylindrical member may be brought into contact with the outer surface of the coil up to near the distal end of the coil, which is the base end of the curve. This prevents the coil from deforming by expanding radially even when compressed due to wire pulling, and prevents twisting of the curved distal portion of the catheter due to the rotation of the leaf spring connected to the coil. Since the ease with which the coil expands depends on the number of turns of the coil, the above effect can be achieved by making the length in the longitudinal direction of the first section 1 turn or less of a predetermined number of turns of the coil. Moreover, since the length in the longitudinal direction of the first section where the inner wall of the cylindrical member does not contact the outer surface of the coil is 1 turn or more of the coil, it is possible to make it less likely for a rigidity step to occur in the longitudinal direction of the distal portion of the catheter, thus preventing kinking when the distal portion of the catheter is curved. As a result, it is possible to create a catheter that achieves the desired curved shape of the distal portion and can be easily delivered to the desired position, thereby facilitating catheter-based examinations and treatments, and preventing accidents such as the distal portion of the catheter damaging the lumen wall of the body or advancing in an undesirable direction.

[0020] A catheter according to an embodiment of the present invention will be described with reference to Figures 1 to 8. Figure 1 is a plan view of a catheter according to one embodiment of the present invention, and the dotted line shows the case when the distal portion of the catheter is curved towards one side of the leaf spring in the radial direction of the shaft. Figure 2 is a cross-sectional view in the longitudinal direction when the distal portion of the catheter shown in Figure 1 is not curved, and only the coil is a plan view. Figures 3 to 6 each show cross-sectional views at different points in the longitudinal direction of the catheter shown in Figure 2, with Figure 3 being a cross-sectional view along line III-III in Figure 2, Figure 4 being a cross-sectional view along line IV-IV in Figure 2, Figure 5 being a cross-sectional view along line VV in Figure 2, and Figure 6 being a cross-sectional view along line VI-VI in Figure 2. Figure 7 is a plan view of a coil according to one embodiment of the present invention, and Figure 8 is a plan view of the coil shown in Figure 7 when it is at maximum compression.

[0021] In this invention, the proximal side refers to the direction toward the user's proximal side in the extending direction of the catheter 1, and the distal side refers to the opposite direction from the proximal side, i.e., the direction toward the person being treated. The extending direction of the catheter 1 is the longitudinal axis direction d of the shaft 2. L It is preferable that it be the same as the longitudinal axis d L In a cross-section perpendicular to the axis, the direction connecting the center of shaft 2 and a point on the circumscribed circle of shaft 2 is the radial direction d. R This is referred to as [the term]. In the figures in this specification, the lower side of the figure is the proximal side and the upper side of the figure is the distal side.

[0022] As shown in Figure 1, the catheter 1 is in the longitudinal direction d L It has a distal end and a proximal end, and its longitudinal axis d L The device has a shaft 2 with an internal lumen that extends to the body. The distal end of the shaft 2 is inserted into the body, and the distal end is delivered to the treatment site by manipulating the proximal end. Therefore, flexibility is preferable, and metal or resin can be used as the material. Since it is inserted into the body, it is preferable that the shaft 2 is made of a biocompatible material.

[0023] Examples of materials that make up shaft 2 include polyolefin resins such as polyethylene and polypropylene; polyamide resins such as nylon; polyester resins such as PET; polyimide resins; aromatic polyetherketone resins such as PEEK; polyether polyamide resins; polyurethane resins; fluororesins such as PTFE, PFA, and ETFE; vinyl chloride resins; synthetic resins such as silicone resins, and natural rubber. Shaft 2 may have a single-layer structure or a multi-layer structure. If shaft 2 has a multi-layer structure, for example, a metal braid made of stainless steel, carbon steel, nickel-titanium alloy, etc. can be used as the intermediate layer of the resin tubes that make up shaft 2.

[0024] The surface of shaft 2 can be used to arrange components for examination and treatment, such as electrodes and sensors. The lumen of shaft 2 can also accommodate internal structures for curving the distal end 1D of the catheter, as well as components such as wires for connecting electrodes and sensors. By connecting the distal end of the wire to an electrode on the surface of shaft 2 and the proximal end of the wire to a detector or power supply via the proximal end of catheter 1, electrical signals from the electrodes can be received and current can be supplied to the electrodes. With this configuration, catheter 1 can be used as an electrode catheter for measuring electrocardiograms or as an ablation catheter for cauterizing tissue. The longitudinal axis direction of shaft 2 is d. L The length, outer diameter, thickness, etc., can be selected to suit the intended use.

[0025] Preferably, a tip portion 20 is positioned at the distal end of the shaft 2. The tip portion 20 may be a separate component from the shaft 2, or it may be formed as part of the same component. If the tip portion 20 is a separate component from the shaft 2, it may include a portion that is inserted into the lumen of the shaft 2 and a portion that protrudes distal to the distal end of the shaft 2. If the tip portion 20 is formed as part of the shaft 2, the tip portion 20 may be formed by sealing the opening at the distal end of the shaft 2 by heat fusion or the like.

[0026] Preferably, the handle 7 is positioned on the proximal side of the shaft 2, and preferably the proximal end of the shaft 2 is fixed inside the handle 7. Preferably, the conductor extending from the lumen of the shaft 2 and the proximal end of the wire 30, described later, are positioned inside the handle 7. The handle 7 may be equipped with a wire operating section 70 to facilitate the manipulation of the wire 30. By fixing the proximal end of the wire 30 to the wire operating section 70, the wire operating section 70 can be operated to pull or release the wire 30, thereby bending or returning the distal portion 1D of the catheter to its original position.

[0027] As shown in Figure 2, the catheter 1 consists of a wire 30 extending into the lumen of the shaft 2, a leaf spring 40, and a longitudinal axis d L The device includes a coil 50 having a lumen extending to the end of the curve. The wire 30 is a pulling member, the leaf spring 40 is a bending member, and the coil 50 is a member positioned on the proximal end side of the curve. By pulling the wire 30, the leaf spring 40 bends, and the distal portion 1D of the catheter distal to the distal end of the coil 50 can be curved.

[0028] As shown in Figures 2, 5, and 6, the leaf spring 40 has a longitudinal axis direction d LIt is preferable that the leaf spring 40 extends in a plate-like shape and has one surface 40a and the other surface 40b. The plate-like shape of the leaf spring 40 can define the curvature direction of the distal portion 1D of the catheter, and the distal portion 1D of the catheter can be curved toward the one surface 40a side and / or the other surface 40b side of the leaf spring 40. The leaf spring 40 has a first connection portion 41 in which the proximal end of the leaf spring 40 is directly or indirectly connected to the distal end of the coil 50. The proximal end of the leaf spring 40 may be fixed to the distal end of the coil 50 by adhesive, solder, laser welding, etc., as shown in Figure 5, thereby forming the first connection portion 41. Alternatively, although not shown, the proximal end of the leaf spring 40 may abut against the distal end of the coil 50, thereby forming the first connection portion 41 without using any special fixing means. The first connecting portion 41, to which the proximal end of the leaf spring 40 and the distal end of the coil 50 are connected, may not be formed by the ends directly contacting or being fixed, but rather by the vicinity of each end contacting or being fixed indirectly.

[0029] The positional relationship between the leaf spring 40 and the coil 50 at the first connection portion 41 can be arbitrary. For example, the proximal end of the leaf spring 40 may be positioned inside the lumen of the coil 50, or it may be positioned outside the coil 50. Alternatively, the proximal end of the leaf spring 40 may be in contact with or fixed to the distal end of the coil 50. Among these positional relationships, it is particularly preferable that at the first connection portion 41, a part of the proximal end of the leaf spring 40 is positioned inside the lumen of the coil 50, and the coil 50 is in a state where it is receiving the proximal end of the leaf spring 40. This allows for a stable connection between the leaf spring 40 and the coil 50.

[0030] Furthermore, the leaf spring 40 has a second connecting portion 42 to which the distal end of the leaf spring 40 is directly or indirectly fixed to the distal end of the shaft 2. At the second connecting portion 42, the distal end of the leaf spring 40 may be directly fixed to the distal end of the shaft 2. Alternatively, the ends of the leaf spring 40 and the shaft 2 may not be directly fixed, but rather the vicinity of each end may be fixed. For example, the distal end of the leaf spring 40 may be indirectly fixed to the distal end of the shaft 2, such as when a tip portion 20 is provided at the distal end of the shaft 2 and the distal end of the leaf spring 40 is fixed to the tip portion 20. The method of fixing the distal end of the leaf spring 40 and the distal end of the shaft 2 is not particularly limited, but examples of fixing methods include adhesive, solder, and laser welding.

[0031] The leaf spring 40 is a spring made of plate material, and examples of materials that make up the leaf spring 40 include metals such as stainless steel, titanium, carbon steel, nickel-titanium alloy, cobalt-chromium alloy, and tungsten alloy. Alternatively, the material that makes up the leaf spring 40 may be a synthetic resin such as aromatic polyether ketone resin (e.g., PEEK), polycarbonate resin, or fiber-reinforced resin. Alternatively, the leaf spring 40 may be made of synthetic rubber or natural rubber such as butadiene rubber, isoprene rubber, styrene-butadiene rubber, ethylene propylene rubber, acrylic rubber, or silicone rubber. Among these, the material that makes up the leaf spring 40 is preferably metal, and more preferably stainless steel.

[0032] The wire 30 is a traction member for bending the distal portion 1D of the catheter. By pulling the wire 30 proximal, the leaf spring 40 bends toward one side 40a or the other side 40b, thereby bending the distal portion 1D of the catheter toward one side 40a or the other side 40b. The degree of bending of the leaf spring 40 can be adjusted by changing the force applied to pull the wire 30 proximal. When the traction on the wire 30 is released, the curvature of the leaf spring 40 returns to its original state, returning the distal portion 1D of the catheter to its original state before bending. For example, by positioning the wire 30 toward one side 40a of the leaf spring 40, the leaf spring 40 can be bent toward one side 40a, and by positioning the wire 30 toward the other side 40b of the leaf spring 40, the leaf spring 40 can be bent toward the other side 40b. Multiple wires 30 may be arranged; for example, by arranging wires 30 on one side 40a and the other side 40b of the leaf spring 40, it is possible to create a catheter 1 that can be bent on both the one side 40a and the other side 40b.

[0033] As shown in Figure 2, the wire 30 extends into the lumen of the coil 50. The distal end of the wire 30 is connected directly or indirectly to the distal end of the shaft 2 distal to the distal end of the coil 50. This allows the distal portion 1D of the catheter to be curved by pulling the wire 30. Preferably, the distal end of the wire 30 is connected to the distal end of the shaft 2, but it may also be connected to the distal end of the shaft 2. The distal end of the wire 30 may be connected by being directly fixed to the distal end of the shaft 2, or it may be connected indirectly by being fixed to the tip portion 20 or other members located at the distal end of the shaft 2, such as a leaf spring 40. Which part of the distal end of the wire 30 is connected to the distal end of the shaft 2, and which part of the distal end of the shaft 2 the wire 30 is connected to, can be appropriately selected depending on the desired curved shape of the distal portion 1D of the catheter.

[0034] As the wire 30, a metal wire such as stainless steel or a wire formed of a synthetic resin such as a fluororesin can be used. One wire 30 may be a single wire or may have a structure composed of a plurality of wires. The wire 30 and the shaft 2 may be connected by fixing them in the same manner as the fixing method described for fixing the leaf spring 40 and the shaft 2, or the distal end portion of the wire 30 may be abutted so as to stretch against the distal end portion of the shaft 2 or its periphery, whereby they may be connected without using a special fixing means.

[0035] Since the catheter 1 has the coil 50, the rigidity of the proximal side of the curvature of the distal portion 1D of the catheter is ensured, and the distal portion 1D of the catheter on the distal side can be curved from the distal end portion of the coil 50 in the longitudinal axis direction d. L In order to make the rigidity of the proximal side of the curvature of the distal portion 1D of the catheter be equal to or higher than a certain level, the coil 50 is preferably a non-compressible, so-called closely wound coil. If the coil 50 is non-compressible, it becomes easy for the distal portion 1D of the catheter to curve starting from the distal end portion of the coil 50. As shown in FIGS. 7 and 8, strictly speaking, a non-compressible coil is one in which the ratio L of the total length L of the coil in the natural state where no external force is applied to the coil to the total length L of the coil at the maximum compression is 1, but cases where L / L is 0.95 or more and 0.9 or more are also substantially included in non-compressible coils. If the coil 50 is such a non-compressible coil, the rigidity of the proximal side of the curvature of the distal portion 1D of the catheter can be easily ensured, and the distal portion 1D of the catheter on the distal side can be curved from the distal end portion of the coil 50. The coil 50 may extend to the proximal end of the shaft 2, the coil 50 may extend beyond the proximal end of the shaft 2, and the proximal end of the coil 50 may be arranged in the middle of the shaft 2. The coil 50 may be switched to a different tube in the middle of the shaft 2 in the longitudinal axis direction d. c and c / L is 1, but cases where L c / L is 0.95 or more and 0.9 or more are also substantially included in non-compressible coils. If the coil 50 is such a non-compressible coil, the rigidity of the proximal side of the curvature of the distal portion 1D of the catheter can be easily ensured, and the distal portion 1D of the catheter on the distal side can be curved from the distal end portion of the coil 50. The coil 50 may extend to the proximal end of the shaft 2, the coil 50 may extend beyond the proximal end of the shaft 2, and the proximal end of the coil 50 may be arranged in the middle of the shaft 2. The coil 50 may be switched to a different tube in the middle of the shaft 2 in the longitudinal axis direction d. L in

[0036] The coil 50 is preferably flexible and can be made of metal or resin. For example, it can be made of metal wire such as stainless steel or nickel-titanium alloy, or synthetic resin wire such as aromatic polyether ketone resin (e.g., PEEK) or polycarbonate resin. The cross-sectional shape of the coil wire 55 forming the coil 50 can be circular, square, or a combination thereof. In particular, the coil 50 is preferably a coil made by winding a metal wire, and it is more preferably a coil made by winding a stainless steel coil wire 55 with a circular cross-sectional shape. When the coil 50 is formed with a coil wire 55 with a circular cross-sectional shape, the diameter of the coil wire 55 is preferably 0.1 mm to 0.5 mm. When the coil 50 is formed with a coil wire 55 with a square cross-sectional shape, the side length of the square can be 0.05 mm to 1 mm. The catheter 1 according to the embodiment of the present invention has a longitudinal axis direction d L Since the internal structure changes at the distal end of the coil 50, it is preferable to select the material, size, and flexibility of the coil 50 so that the rigidity of the catheter 1 does not differ too greatly between the distal and proximal ends of the coil 50.

[0037] As shown in Figures 2 and 5, the catheter 1 is in the longitudinal direction d L A cylindrical member 60 having a lumen extending in a certain direction, the cylindrical member 60 being positioned outside the coil 50 such that a wire 30, a leaf spring 40, and a first connecting portion 41 are arranged inside the lumen of the cylindrical member 60. L In this configuration, the distal end of the cylindrical member 60 may be positioned near the distal end of the shaft 2 such that most of the leaf spring 40 is positioned inside the lumen of the cylindrical member 60, or it may be positioned midway between the first connecting portion 41 and the distal end of the shaft 2 such that a portion of the leaf spring 40 is positioned inside the lumen of the cylindrical member 60. The cylindrical member 60 may extend to the proximal end of the shaft 2, or it may extend beyond the proximal end of the shaft 2, and the proximal end of the cylindrical member 60 may be positioned in the middle of the shaft 2.

[0038] As for the material constituting the cylindrical member 60, you can refer to the description of synthetic resins among the materials constituting the shaft 2, but among them, elastomers made of polyolefin resins, polyimide resins, and polyamide resins are preferred.

[0039] As shown in Figure 2, the longitudinal axis d L In this configuration, the cylindrical member 60 has a first section S1 from the distal end of the coil 50 to point D of length d on the proximal side, and a second section S2 from point D to the proximal end of the cylindrical member 60. In the first section S1, the inner wall of the cylindrical member 60 does not contact the outer surface of the coil 50, and the length d is between 1 turn and 30 turns of the coil 50. That is, in the catheter 1 according to the embodiment of the present invention, as shown in Figure 3, the cylindrical member 60 is arranged on the outside of the coil 50, and in the first section S1, as shown in Figures 4 and 5, the inner wall of the cylindrical member 60 does not contact the outer surface of the coil 50, and distal to the distal end of the coil 50, as shown in Figure 6, a leaf spring 40 and a wire 30 are arranged in the lumen of the cylindrical member 60. This configuration prevents interference between the cylindrical member 60 and the wire 30, which is a traction member, and the leaf spring 40, which is a bending member. As a result, force from the proximal end is easily transmitted to the wire 30 located at the distal end 1D of the catheter, and the bending of the leaf spring 40 due to the pulling of the wire 30 is less affected by the cylindrical member 60, making it easier to achieve the desired curved shape of the distal end 1D of the catheter.

[0040] Longitudinal axis direction d L In this configuration, the cylindrical member 60 may extend to the proximal end of the coil 50, or the proximal end of the cylindrical member 60 may be located distal to the proximal end of the coil 50. The cylindrical member 60 may be composed of a single member from the distal end to the proximal end, or along the longitudinal axis d L The member may switch to another member at any of the following positions. The position at which the cylindrical member 60 switches to another member is not particularly limited; for example, it may switch at point D, or it may switch at any other position. Longitudinal axis direction d LIn this configuration, it is preferable that the cylindrical member 60 is positioned outside the coil 50 for a section of 50% or more of the length of the coil 50. The section in which the cylindrical member 60 is positioned outside the coil 50 is more preferably 60% or more of the length of the coil 50, even more preferably 75% or more, and may be 80% or more, 90% or more, or 100%. By positioning the cylindrical member 60 outside the coil 50 within the above range, the cylindrical member 60 provides radial support to the coil 50. R This makes it easier to prevent swelling.

[0041] As shown in Figures 2 to 5, the cylindrical member 60 is positioned outside the coil 50 such that the first connecting portion 41 is located inside its lumen. This ensures that even when the coil 50 is compressed by the pulling of the wire 30 when the distal portion 1D of the catheter is bent, the coil 50 does not move in the radial direction d R This prevents deformation that causes it to bulge, and suppresses the twisting of the leaf spring 40 due to the rotation of the first connection part 41. As a result, it becomes easier to bend the distal part 1D of the catheter into the desired shape.

[0042] Here, one turn of the coil 50 refers to the length of one turn of the coil wire 55 forming the coil 50 in a natural state without applying any external force to the coil 50, as shown in Figure 7, along the longitudinal axis d of the coil 50. L This is the length of the coil. Coil 50 is an uncompressible coil, and the total length L of the coil in its natural state and the total length L of the coil when it is fully compressed are shown. c Ratio L c When / L is 1, one turn of coil 50 corresponds to the wire diameter of the coil wire 55 that forms coil 50. When coil 50 is not a completely incompressible coil, as shown in Figure 7, one turn of coil 50 corresponds to the longitudinal axis d of coil 50. L In this case, the length S can be determined as the distance from one end of one turn of the coil wire 55 to one end of the next turn. When the coil 50 is not an incompressible coil, the length S is the sum of the wire diameter of the coil wire 55 and the length of the gap between the coil wires 55, and is the same as the pitch of the coil 50. For example, the length of 30 turns of the coil 50 is 30 times the length S.

[0043] The length d of the first section S1 of the cylindrical member 60 is at least one turn, preferably three turns or more, more preferably four turns or more, even more preferably five turns or more, and may be seven turns or more. In the first section S1 within the above range, the lower limit of length d is such that the inner wall of the cylindrical member 60 does not contact the outer surface of the coil 50, thereby preventing interference of the cylindrical member 60 with the wire, which is the traction member, and the leaf spring, which is the bending member. As a result, the force from the proximal side is easily transmitted to the wire 30 located in the distal part 1D of the catheter, and the bending of the leaf spring 40 due to the traction of the wire 30 is less affected by the cylindrical member 60, resulting in a catheter 1. Furthermore, at the distal end of the coil 50 where a rigidity step occurs, the lower limit of length d of the first section S1 where the inner wall of the cylindrical member 60 does not contact the outside of the coil 50 is within the above range, thus suppressing further rigidity steps caused by the cylindrical member 60, and preventing kinking when the distal part 1D of the catheter is bent.

[0044] The length d of the first section S1 of the cylindrical member 60 is 30 turns or less, preferably 25 turns or less, more preferably 20 turns or less, and may be 15 turns or less, 12 turns or less, or 10 turns or less. In the second section S2, which is proximal to the first section S1 within the above range, the cylindrical member 60 may be brought into contact with the outer surface of the coil 50 up to near the distal end of the coil 50, which is the base end of the curve. Therefore, even if the coil 50 is compressed due to the pulling of the wire 30, the radial direction d R This prevents deformation that causes the coil 50 to bulge, and prevents twisting of the distal portion 1D of the catheter due to the rotation of the leaf spring 40 connected to the coil 50. Since the ease with which the coil 50 bulges depends on the number of turns of the coil 50, the above effect can be achieved by keeping the length d of the first section S1 less than or equal to a predetermined number of turns of the coil 50.

[0045] In the second section S2, the inner wall of the cylindrical member 60 may or may not be in full or partial contact with the outer surface of the coil 50. As shown in Figures 13 to 15, when the inner wall of the cylindrical member 60 is not in contact with the outer surface of the coil 50, a gap may be formed between the inner wall of the cylindrical member 60 and the outer surface of the coil 50. However, if the inner wall of the cylindrical member 60 is not in contact with the outer surface of the coil 50 in the second section S2, the radial direction d R In the cross-section, it is preferable that the area s2 of the gap between the inner wall of the cylindrical member 60 and the outer surface of the coil 50 in the second section S2 is smaller than the area s1 of the gap between the inner wall of the cylindrical member 60 and the outer surface of the coil 50 in the first section S1. The above effect can be achieved by having the cylindrical member 60 with such a configuration. In the second section S2, if the inner wall of the cylindrical member 60 is not in contact with the outer surface of the coil 50, the position D at a length d from the distal end of the coil represents the position where the area s1 of the gap between the inner wall of the cylindrical member 60 and the outer surface of the coil 50 changes to area s2.

[0046] As shown in Figures 2 and 3, it is preferable that in the second section S2, at least a portion of the inner wall of the cylindrical member 60 is in contact with the outer surface of the coil 50. More preferably, in the second section S2, the entire inner wall of the cylindrical member 60 is in contact with the outer surface of the coil 50. This allows the coil 50 to move in the radial direction d R This makes it easier to suppress swelling.

[0047] In order to provide the cylindrical member 60 such that its inner wall abuts the outer surface of the coil 50 in the second section S2, for example, the coil 50 can be placed inside the cavity of a cylindrically molded resin, and the resin can be heat-shrinked on the outside of the coil 50. If the cylindrical member 60 is formed on the outer surface of the coil 50 in this way, the cylindrical member 60 will be in close contact with the outer surface of the coil 50 in the second section S2, and the radial direction d of the coil 50 RThis makes it even easier to suppress bulging. However, even when the cylindrical member 60 is formed to be in close contact with the outer surface of the coil 50, the cylindrical member 60 is not fixed to the outer surface of the coil 50, and the cylindrical member 60 and the coil 50 are separated by a longitudinal axis d L They may be slidable relative to each other. This prevents the coil 50 from being unnecessarily constrained by the cylindrical member 60, thereby improving the flexibility of the catheter 1. In this case, to form the first section S1, methods such as thinning the thickness of the portion of the cylindrical resin corresponding to the first section S1 and not allowing that portion to shrink by heat can be employed.

[0048] Longitudinal axis direction d L In this configuration, it is preferable that the first connecting portion 41 is located in the first section S1. As an example is shown in Figure 5, the first connecting portion 41 is the part where the leaf spring 40 is connected to the coil 50, and therefore is likely to have high rigidity. However, since this portion is located in the first section S1, that is, the inner wall of the cylindrical member 60 does not come into contact with the outer surface of the coil 50 in the portion where the first connecting portion 41 is located, it is possible to prevent further rigidity steps caused by the cylindrical member 60.

[0049] Next, with reference to Figure 9, a catheter according to another embodiment of the present invention will be described. As shown in Figure 9, the cylindrical member 60 extends to the second connection portion 42, and it is preferable that the leaf spring 40 and wire 30 are arranged in the lumen of the cylindrical member 60 at the distal end of the shaft 2. By extending the cylindrical member 60 to the second connection portion 42 in this way, it is preferable that the leaf spring 40 and wire 30 are not exposed in the lumen of the shaft 2. That is, it is preferable that the leaf spring 40 and wire 30 are arranged in the lumen of the cylindrical member 60. This allows the cylindrical member 60 to protect the leaf spring 40 and wire 30, which are prone to damage from repeated bending and traction during repeated use. Furthermore, if the catheter 1 has a conductor connected to an electrode or the like located at the distal end of the distal portion 1D of the catheter, interference between the conductor and the leaf spring 40 and wire 30 can be prevented by arranging the conductor inside the shaft 2 and outside the cylindrical member 60. The cylindrical member 60 extends to the second connecting portion 42, in the longitudinal axis direction d L This includes the fact that the cylindrical member 60 extends to the proximal end of the second connecting portion 42, and extends to the vicinity of the proximal end of the second connecting portion 42.

[0050] Next, with reference to Figure 10, a catheter according to yet another embodiment of the present invention will be described. As shown in Figure 10, the longitudinal axis direction d L In this configuration, the proximal end of the cylindrical member 60 is located distal to the proximal end of the coil 50, and the coil 50 preferably has a first fixing portion 51 that is fixed to the shaft 2 proximal to the proximal end of the cylindrical member 60. Having the first fixing portion 51 fixed to the shaft 2 makes it easier to suppress twisting of the coil 50, and allows the distal portion 1D of the catheter to be curved in a certain direction without twisting. It is preferable that the first fixing portion 51 is formed not by the coil 50 and the shaft 2 being in close contact, but by some fixing means such as bonding with an adhesive or brazing with solder.

[0051] Longitudinal axis direction d LIn this configuration, the length L1 from the distal end of the first fixing portion 51 to the proximal end of the cylindrical member 60 is preferably 20 turns or less of the coil 50. More preferably, the length L1 is 15 turns or less of the coil 50, even more preferably 12 turns or less, and may be 10 turns or less. Furthermore, since the first fixing portion 51 may be provided so as to be in contact with the proximal end of the cylindrical member 60, an configuration in which the length L1 is 0 (zero) and there is no separation between the distal end of the first fixing portion 51 and the proximal end of the cylindrical member 60 is also acceptable. Alternatively, the distal end of the first fixing portion 51 and the proximal end of the cylindrical member 60 may be separated, in which case the length L1 is preferably 3 turns or more of the coil 50, and more preferably 5 turns or more. Since the upper limit of length L1 is within the above range, the first fixing portion 51 can be provided near the proximal end of the cylindrical member 60, thereby making it easier to prevent twisting of the coil 50 and allowing the distal portion 1D of the catheter to be curved in a certain direction without twisting. Since the lower limit of length L1 is within the above range, the first fixing portion 51 can be provided from the proximal end of the cylindrical member 60 in the longitudinal axis direction d L Since it can be positioned a certain distance proximal to the catheter, the rigidity change due to the cylindrical member 60 and the rigidity change due to the first fixing part 51 can be prevented from overlapping, thereby improving the flexibility of the distal part 1D of the catheter and making it easier to achieve the desired curved shape.

[0052] Alternatively, although not shown in the diagram, the first fixing part 51 has a longitudinal axis direction d L In this configuration, the first fixing portion 51 may be provided so as to extend distally beyond the proximal end of the cylindrical member 60, and a part of the first fixing portion 51 may be used to fix the cylindrical member 60 and the shaft 2.

[0053] Longitudinal axis d of the first fixing part 51 L The length is preferably 50 turns or less of the coil 50, more preferably 30 turns or less, and even more preferably 10 turns or less. The longitudinal axis direction d of the first fixing part 51 L If the length is long, the rigidity of the distal portion 1D of the catheter where the first fixing part 51 is provided will increase, and there is a risk that problems such as kinking of the distal portion 1D of the catheter may occur due to the difference in rigidity, but the longitudinal axis d of the first fixing part 51 LIf the length is within the above range, the rigidity step caused by the first fixing part 51 can be reduced. Also, if the catheter 1 has a wire connected to an electrode or the like located at its tip, the wire is located inside the shaft 2 and outside the coil 50, so the longitudinal axis direction d of the first fixing part 51 L The length of the first fixing part 51 is within the above range, which suppresses the influence of the first fixing part 51 on the conductor, prevents the conductor from becoming distorted, and makes it possible to easily bend the distal part 1D of the catheter into the desired shape. L There is no particular lower limit to the length, but for example, it is preferably 3 turns or more of the coil 50, more preferably 5 turns or more, and even more preferably 7 turns or more. (Long axis direction d) L In this configuration, it is preferable that the length of the second section S2, the length of the first fixing part 51, and the length L1 from the distal end of the first fixing part 51 to the proximal end of the cylindrical member 60 decrease in that order. With such a configuration, deformation and twisting such as swelling of the coil 50 can be prevented by the cylindrical member 60 and the first fixing part 51, while the influence of rigidity differences between each member can be reduced, making it easier to give the distal part 1D of the catheter the desired curved shape.

[0054] The first fixing portion 51 may be provided in the entire 360° circumferential direction of the space outside the coil 50 and inside the shaft 2, as shown in Figure 11, or it may be provided in a part of the 360° circumferential direction of the space, as shown in Figure 12. If the first fixing portion 51 is provided in a part of the 360° circumferential direction of the space, there may be one or more first fixing portions 51. In this case, the sum of the angles in which the first fixing portion 51 is provided in the circumferential direction is preferably 60° or more, and more preferably 90° or more. If the first fixing portion 51 is provided within the above range, the fixing strength between the coil 50 and the shaft 2 can be ensured. Furthermore, the sum of the angles in which the first fixing portion 51 is provided in the circumferential direction is preferably 240° or less, and more preferably 180° or less. If the first fixing portion 51 is provided within the above range, the rigidity step caused by the first fixing portion 51 can be suppressed. Furthermore, if the catheter 1 has a wire connected to an electrode or the like located at its tip, the wire can be inserted into the space outside the coil 50 and inside the shaft 2 where the first fixing part 51 is not located. This allows the wire to be configured so that it is not fixed by the first fixing part 51, preventing the wire from becoming distorted and making it possible to easily bend the distal part 1D of the catheter into the desired shape.

[0055] In one embodiment of the present invention, in which the proximal end of the cylindrical member 60 is located distal to the proximal end of the coil 50 as described above, the longitudinal axis direction d L The length of the cylindrical member 60 is preferably 1 / 4 or more of the length of the leaf spring 40. This allows the coil 50 to function in the radial direction d R This improves the effect of preventing deformation such as bulging, and also improves the longitudinal axis direction d of the first fixing part 51. L Since the position at this point can be sufficiently far from the first connection part 41, the stiffness change due to the first connection part 41 and the stiffness change due to the first fixing part 51 can be prevented from overlapping, making it easier to improve the flexibility of the distal part 1D of the catheter and achieve the desired curved shape.

[0056] Next, with reference to Figure 13, a catheter according to yet another embodiment of the present invention will be described. As shown in Figure 13, it is preferable that the catheter 1 in yet another embodiment of the present invention has a second fixing portion 61 in which the cylindrical member 60 is fixed to the shaft 2 in the second section S2. By having a second fixing portion 61 in which the cylindrical member 60 is fixed to the shaft 2, it becomes easier to prevent twisting of the coil 50 and to bend the distal portion 1D of the catheter in a certain direction without twisting. It is preferable that the second fixing portion 61 is formed not by simply being in close contact with the cylindrical member 60 and the shaft 2, but by some fixing means such as bonding with an adhesive or brazing with solder. By fixing the cylindrical member 60 to the shaft 2 instead of the coil 50 which has a certain degree of rigidity or more, it is possible to improve the flexibility of the distal portion 1D of the catheter while preventing twisting of the distal portion 1D of the catheter. Also, the cylindrical member 60 and the coil 50 are in the longitudinal axis direction d L In an embodiment in which the cylindrical member 60 can slide against each other, even if the cylindrical member 60 is fixed to the shaft 2, a certain degree of freedom is ensured for the coil 50, so that the flexibility of the distal portion 1D of the catheter is not easily impaired.

[0057] In the above embodiment, the cylindrical member 60 has a longitudinal axis direction d L It may extend to the proximal end of the coil 50. Alternatively, the proximal end of the cylindrical member 60 is in the longitudinal axis direction d L The catheter 1 may further have a first fixing portion 51 located distal to the proximal end of the coil 50, to which the coil 50 is fixed to the shaft 2 proximal to the proximal end of the cylindrical member 60. In other words, the catheter 1 may have both the first fixing portion 51 and the second fixing portion 61.

[0058] The longitudinal axis direction d of the second fixing part 61 L The length is preferably 50 turns or less of the coil 50, more preferably 30 turns or less, and even more preferably 10 turns or less. The longitudinal axis direction d of the second fixing part 61 LIf the length is long, the rigidity of the distal portion 1D of the catheter where the second fixing part 61 is provided will increase, and there is a risk that problems such as kinking of the distal portion 1D of the catheter may occur due to the difference in rigidity, but the longitudinal axis d of the second fixing part 61 L If the length is within the above range, the rigidity step caused by the second fixing part 61 can be reduced. Also, if the catheter 1 has a conductor connected to an electrode or the like located at its tip, the conductor is located inside the shaft 2 and outside the coil 50 and the cylindrical member 60, so the longitudinal axis direction d of the second fixing part 61 L The length of the second fixing part 61 is within the above range, which suppresses the influence of the second fixing part 61 on the conductor, prevents the conductor from becoming distorted, and makes it possible to easily bend the distal part 1D of the catheter into the desired shape. L There is no particular lower limit to the length, but for example, it is preferably three turns or more of the coil 50, more preferably five turns or more, and even more preferably seven turns or more.

[0059] The second fixing portion 61 may be provided in the entire 360° circumferential direction of the space outside the cylindrical member 60 and inside the shaft 2, as shown in Figure 14, or it may be provided in a part of the 360° circumferential direction of the space, as shown in Figure 15. If the second fixing portion 61 is provided in a part of the 360° circumferential direction of the space, there may be one or more second fixing portions 61. In this case, the sum of the angles in which the second fixing portion 61 is provided in the circumferential direction is preferably 60° or more, and more preferably 90° or more. If the second fixing portion 61 is provided within the above range, the fixing strength between the cylindrical member 60 and the shaft 2 can be ensured. Furthermore, the sum of the angles in which the second fixing portion 61 is provided in the circumferential direction is preferably 240° or less, and more preferably 180° or less. If the second fixing portion 61 is provided within the above range, the rigidity step caused by the second fixing portion 61 can be suppressed. Furthermore, if the catheter 1 has a wire connected to an electrode or the like located at its tip, the wire can be inserted into the space outside the cylindrical member 60 and inside the shaft 2 where the second fixing part 61 is not located. This allows the wire to be configured not to be fixed by the second fixing part 61, preventing the wire from becoming distorted and making it possible to easily bend the distal part 1D of the catheter into the desired shape.

[0060] Longitudinal axis direction d L In this configuration, the length L2 from the distal end of the second fixing part 61 to the distal end of the coil 50 is preferably twice the length of the leaf spring 40 or less. More preferably, the length L2 is 1.5 times or less the length of the leaf spring 40, and even more preferably 1 time or less. Furthermore, the length L2 is preferably 1 / 3 or more of the length of the leaf spring 40, more preferably 1 / 2 or more, and even more preferably 3 / 4 or more. If the length L2 is within the above range, the longitudinal axis direction d L In this configuration, the cylindrical member 60 and the shaft 2 can be fixed within a predetermined position proximal to the distal end of the coil 50, which is the base end of the curve when the distal portion 1D of the catheter is curved. This makes it easier to prevent twisting of the coil 50, and allows the distal portion 1D of the catheter to be curved in a certain direction without twisting.

[0061] Longitudinal axis direction d LIn this configuration, the distal end of the second fixing portion 61 is located more proximal to the proximal end of the first connecting portion 41, and the length L3 from the distal end of the second fixing portion 61 to the proximal end of the first connecting portion 41 is preferably 1 / 4 or more of the length of the leaf spring 40. More preferably, the length L3 is 1 / 3 or more of the length of the leaf spring 40, and even more preferably 1 / 2 or more. The upper limit of the length L3 can be the same as the preferred range of the length L2 described above. If the length L3 is within the above range, the longitudinal axis direction d of the second fixing portion 61 L Since the position at the first connection part 41 can be sufficiently far away from the second fixing part 61, the stiffness change due to the first connection part 41 and the stiffness change due to the second fixing part 61 can not overlap, making it easier to improve the flexibility of the distal part 1D of the catheter and achieve the desired curved shape.

[0062] The catheter 1 according to yet another embodiment of the present invention shown in Figure 13 may have other fixing parts in which the coil 50 or cylindrical member 60 is fixed to the shaft 2 proximal to the proximal end of the second fixing part 61. While this has little effect on the change in the rigidity of the catheter 1 because it is sufficiently far from the distal end of the coil 50 and the first connection part 41 as it is proximal to the proximal end of the second fixing part 61, it is preferable that the number of fixing parts be kept to a minimum from the viewpoint of reducing the number of steps during manufacturing and ensuring smooth sliding of the wires if the catheter 1 has wires. (Longitudinal axis d) L The number of other fixing parts in this configuration is preferably 5 or less, more preferably 3 or less, and may be 2 or less, 1 or less, or 0.

[0063] The catheter 1 shown in Figure 13, according to yet another embodiment of the present invention, has a longitudinal axis d L In this configuration, it is preferable that the cylindrical member 60 and the shaft 2 are not fixed distal to the distal end of the second fixing portion 61. This prevents a portion of the coil 50 from becoming rigid due to the fixing portion near the distal end, thus preventing a rigidity step in the distal portion 1D of the catheter.

[0064] This application claims the benefit of priority based on Japanese Patent Application No. 2021-134329, filed on 19 August 2021. The entire specification of the above Japanese Patent Application No. 2021-134329 is incorporated herein by reference. [Explanation of Symbols]

[0065] 1: Catheter 1D: Distal part of the catheter 2: Shaft 7: Handle 20:Tip 30: Wire 40: Leaf spring 40a: One side 40b: Other side 41: First connection section 42: Second connection section 50: Coil 51: 1st fixed part 55: Coil wire 60: Cylindrical member 61:Second fixed part 70: Wire operation unit d: Length from the distal end of the coil to the distal end of the cylindrical member d L : Long axis direction d R :radial direction L: Length of the coil in its natural state L c : Length of the coil at maximum compression L1: Length from the distal end of the first fixing part to the proximal end of the cylindrical member L2: Length from the distal end of the second fixing part to the distal end of the coil L3: Length from the distal end of the second fixing part to the proximal end of the first connecting part S1: Section 1 S2: Section 2

Claims

1. A shaft having a distal end and a proximal end in the longitudinal direction and a lumen extending in the longitudinal direction, A coil having a lumen extending in the longitudinal direction and positioned within the lumen of the shaft, A leaf spring extending into the lumen of the shaft, having a first connection portion in which the proximal end of the leaf spring is directly or indirectly connected to the distal end of the coil, and a second connection portion in which the distal end of the leaf spring is directly or indirectly fixed to the distal end of the shaft, One or more wires extending into the lumen of the coil, with their distal ends directly or indirectly connected to the distal end of the shaft, The coil comprises a cylindrical member having a lumen extending in the longitudinal direction, wherein the wire, the leaf spring, and the first connecting portion are arranged in the lumen of the cylindrical member, and the cylindrical member is arranged outside the coil. In the longitudinal axis direction, the tubular member has a first section from the distal end of the coil to a point D of length d proximally, and a second section from point D to the proximal end of the tubular member, wherein in the first section the inner wall of the tubular member does not contact the outer surface of the coil, and the length d is between one turn and 30 turns of the coil.

2. The catheter according to claim 1, wherein at least a portion of the inner wall of the cylindrical member is in contact with the outer surface of the coil in the second section.

3. The catheter according to claim 1 or 2, wherein the first connecting portion is located in the first section in the longitudinal axis direction.

4. The catheter according to claim 1, wherein the cylindrical member extends to the second connecting portion, and the leaf spring and the wire are arranged in the lumen of the cylindrical member at the distal end of the shaft.

5. The catheter according to claim 1, wherein in the longitudinal axis direction, the proximal end of the cylindrical member is located distal to the proximal end of the coil, and the coil has a first fixing portion that is fixed to the shaft proximal to the proximal end of the cylindrical member.

6. The catheter according to claim 5, wherein, in the longitudinal axis direction, the length from the distal end of the first fixing portion to the proximal end of the cylindrical member is 20 turns or less of the coil.

7. The catheter according to claim 1, wherein the cylindrical member has a second fixing portion fixed to the shaft in the second section.

8. The catheter according to claim 7, wherein, in the longitudinal axis direction, the length from the distal end of the second fixing portion to the distal end of the coil is 2 times or less the length of the leaf spring.

9. The catheter according to claim 7 or 8, wherein, in the longitudinal axis direction, the distal end of the second fixing portion is located proximal to the proximal end of the first connecting portion, and the length from the distal end of the second fixing portion to the proximal end of the first connecting portion is 1 / 4 or more of the length of the leaf spring.

Images