KR20160113360A

KR20160113360A - Catheter and catheter system

Info

Publication number: KR20160113360A
Application number: KR1020150037467A
Authority: KR
Inventors: 박석호; 박종오; 고성영; 최현철; 정세미; 이청; 고광준
Original assignee: 전남대학교산학협력단
Priority date: 2015-03-18
Filing date: 2015-03-18
Publication date: 2016-09-29
Also published as: KR101740693B1

Abstract

The present invention relates to a catheter capable of steering and tunneling, comprising: a catheter body having a plurality of bodies capable of being attached; And a wire connected to the catheter body and adjusting the clearance between the plurality of bodies. The catheter according to the present invention has a simple structure that is easy to manufacture and has an advantage that it can be steered and tunneled without replacement of the wire.

Description

[0001] CATHETER AND CATHETER SYSTEM [0002]

The present invention relates to a catheter and a catheter system, and more particularly, to a catheter that is easy to steer and tunnel in a blood vessel, a catheter that can be monitored in real time during a procedure and easily enter the catheter to the target site without damaging the vessel wall. &Lt; / RTI >

Generally, a catheter is a flexible tube of a hollow shaft, and is a medical device used for delivering a drug to a local area or puncturing a lesion site by vascular diseases and specific lesions.

To reach the catheter, the catheter is inserted along the wire after reaching the desired site using a thin flexible wire called a guide wire. The insertion of the guidewire is performed by the doctor while viewing the X-ray screen while administering the contrast agent in the blood vessel in real time. In this process, it is difficult to steer the tip of the guide wire, which can take a lot of time, and the patient and the doctor are exposed to the X-ray for a long time and the X-ray exposure continues to increase. If the direction of the tip portion is not directed toward the center of the blood vessel, there is a problem that the inner wall of the blood vessel may be damaged and punctured during the procedure.

On the other hand, it has been reported from a paper related to the treatment of cardiovascular disease that chronic total occlusion (CTO) in which cardiovascular diseases are totally occluded by deposits and blood flow does not flow is found in 52% of patients with severe coronary artery disease have.

Generally, chronic complete stenosis occurs when lipid-rich cholesterol is deposited on the inner wall of the blood vessel and the lumen is occluded. The multilayered lipid and thrombotic complexes constituting the stenotic lesion thus formed are replaced with collagen as time passes, and these collagens form a multimolecular mass from a single molecule, and the collagenization and calcification ) To form a mechanically stable phosphorylated layer to prevent blood circulation.

As a method of treating such chronic stricture, a method of chemically decomposing and reperfusion the fibrin-collagen complex of the stenotic portion and a method of physically perforating the fibrin-collagen complex have been used.

Conventional examples for perforating a chronic stricture lesion include laser angioplasty (laser angioplasty), which uses a laser to instantaneously vaporize and remove materials at the site of stenosis, and high-speed rotating diamond burr, There is a rotational antherectomy. Generally, it is known that rotary cutting method is useful for hardened stricture lesions with calcification. In addition, typical instruments of conventional chronic stricture treatment use high sharpness wire with high stiffness.

As a conventional technique, Japanese Patent Application Laid-Open No. 10-2010-0095782 proposes a device for removing a chronic stricto-striction lesion in a blood vessel. The apparatus includes a potential adjusting unit having a lesion removing tool at a front end portion of a catheter that enters the lumen of a vessel and having a plurality of balloons and a posterior adjusting unit to adjust the position of the lesion removing tool to remove a chronic stricture lesion in the blood vessel I would like to.

As described above, the catheter for tunneling requires excellent operability so that the catheter can pass through a thin and complicated pattern of a blood vessel system, a built-in system, and the like and reach a target point. A catheter with a high-rigid, sharp end should not damage the vessel during its travel to the target site and should be able to push the wire strongly to puncture at the target site.

Conventional catheters have pierced lesions by inserting a flexible guidewire for steering to the target point in the chin and replacing it with a stiff-wire for tunneling upon reaching the target point. Thus, the wire of the catheter for tunneling needs a property of ductility for steering and rigidity required for tunneling so that the direction can be arbitrarily adjusted.

Korean Patent Publication No. 10-2010-0095782, Korean Patent Publication No. 10-2012-0124572

The present invention seeks to provide a catheter that is simple in structure and capable of steering and tunneling without a wire replacement process. More specifically, the present invention seeks to provide a catheter having a structure capable of steering from an externally applied magnetic field and maintaining the rigidity of the wire at the target point.

The present invention also provides a catheter system in which real-time monitoring is performed during a catheter procedure, and the catheter can easily enter the target site without damaging the vessel wall.

In order to achieve the above object, the present invention provides a catheter capable of steering and tunneling, comprising: a catheter body having a plurality of bodies capable of being attached; And a wire connected to the catheter body and adjusting the clearance between the plurality of bodies.

Preferably, the body according to the present invention comprises a magnetic body and can be steered by a magnetic field applied from the outside.

Preferably, the wire according to the present invention may be formed of a different material from a distal portion connected to the distal end of the catheter body and a proximal portion connected to the rear end of the catheter body.

Preferably, a catheter body according to the present invention comprises a first body fixedly connected to a distal portion of a wire; A second body provided between the first body and the third body and having a through hole through which the wire passes; And a third body fixedly connected to the proximal portion of the wire through the wire.

Preferably, the second body according to the invention may be more than one.

Preferably, the end of the first body according to the present invention is conical in shape with a sharp tip, and the end of the second body and the third body may be provided in a hemispherical shape.

Preferably, the wire according to the present invention comprises a rigid wire for pushing the catheter body; And a flexible wire which is inserted into the rigid wire and adjusts the clearance between the plurality of bodies.

Preferably, the flexible wire according to the present invention may be made of a material having higher flexibility than the rigid wire.

Preferably, the rigid wire according to the present invention is fixedly connected to the third body, and the flexible wire is fixedly connected to the first body through the second body.

In addition, the present invention provides a catheter system comprising: a rotary arm provided with a first C-arm and a second C-arm orthogonal to each other and pivotable about a horizontal axis with respect to a ground; An image capturing unit installed at each end of the first C arm to obtain a video image; A magnetic field generator having a pair of coils provided at respective ends of the second C arm so as to face each other and a power supply unit for supplying a magnetizing current for generating an induced magnetic field to the coil; A catheter provided with a magnetic body to perform steering driving by a magnetic field generated by a magnetic field generating unit; And a catheter feeding unit for controlling the catheter.

The catheter according to the present invention is capable of steering the catheter body by adjusting the flexibility of the flexible wires so that the plurality of bodies constituting the catheter body are spaced apart from each other. Further, the flexible wire can be converted into a structure in which rigidity is transmitted so that the rigid wire can press-fit the catheter body, by adjusting the plurality of bodies to be tied together while the catheter is inserted into the sachet. Thus, the catheter according to the present invention has a simple structure that is easy to manufacture, and has an advantage that steering and tunneling can be performed without replacing the wire.

In addition, the catheter system according to the present invention has an advantage that the image capturing means for obtaining the image in real time and the magnetic field generating unit for introducing the catheter to the lesion site using the induction magnetic field can be efficiently arranged without interference with each other.

In addition, the catheter system according to the present invention can change the induced magnetic field by using the detection signal of the F / T sensor part which can detect the reaction force due to contact with the blood vessel wall in the insertion process of the catheter, There is an advantage that it can be prevented. This is advantageous in that the catheter can be positioned efficiently to the target point of the blood vessel and lumen without requiring a high degree of proficiency of the practitioner as compared with the conventional catheter steering method using the guide wire.

Next, the catheter system according to the present invention can remotely control the catheter and insert the catheter to the lesion site in a short time. Therefore, the X-ray of the patient and the doctor by the X- There is an advantage of reducing the amount of exposure.

1 shows a schematic view of a catheter and catheter system according to an embodiment of the present invention.
FIG. 2 shows a state where the catheter according to the embodiment of the present invention is controlled so that the clearance between the bodies can be controlled by the operation of the wire to enable steering and tunneling. FIG. 2A is a longitudinal sectional view in which a flexible wire is converted into a structure in which a catheter body is steerable by adjusting a plurality of bodies constituting a catheter body so as to be spaced apart from each other, FIG. 2B is a cross-sectional view in which a flexible wire binds a plurality of bodies constituting a catheter body So that the stiffness of the rigid wire can be transmitted to the catheter body.
FIG. 3 is a perspective view illustrating a combined body and wire according to an embodiment of the present invention. Referring to FIG.
FIG. 4A is a perspective view of a body and a wire according to another embodiment of the present invention, and FIG. 4B shows a state in which the second body according to FIG. 4A is stitched by a flexible wire.
5 is a view showing a first embodiment of a catheter feeding unit in a catheter system according to the present invention.
6 (a), 6 (b), 6 (c) and 6 (d) illustrate operation examples of the catheter in the catheter system according to the present invention.
Figure 7 is a view of another embodiment of a catheter system in accordance with the present invention to be steered.
8 (a), 8 (b), 8 (c) and 8 (d) illustrate an example of wire operation using the catheter system according to the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to or limited by the exemplary embodiments. Like reference numerals in the drawings denote members performing substantially the same function.

The objects and effects of the present invention can be understood or clarified naturally by the following description, and the purpose and effect of the present invention are not limited by the following description.

The objects, features and advantages of the present invention will become more apparent from the following detailed description. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Figure 1 shows a schematic view of a catheter 10 and catheter system in accordance with an embodiment of the present invention. Referring to FIG. 1, the catheter system of the present invention comprises: a rotary arm 110 provided with a first C-arm 111 and a second C-arm 112 orthogonal to each other and rotatable about a horizontal axis with respect to the ground; An image capturing unit 121 (122) provided at each end of the first C arm 111 to obtain a video image; A pair of coils 131 and 132 provided at the respective ends of the second C arm 112 so as to face each other and a power supply unit 130 for supplying a magnetizing current for generating an induction magnetic field to the coils 131 and 132 133); A movable bed (140) disposed adjacent to the rotary arm (110) and capable of moving back and forth; A catheter 10 connected to the distal end of the catheter 10 so as to perform steering drive by a magnetic field generated by the magnetic field generator; And a catheter feeding unit (200) having a wire (105).

The rotary arm 110 is provided with two C arms 111 and 112 orthogonal to each other so as to be integrally rotated, and the base member 101 may be provided so that the rotary member 110 is rotated with a horizontal axis with respect to the ground surface. Each C arm has a "C" shape with a certain curvature and has opposite ends facing each other.

The rotary arm 110 is provided on the base member 101 with an electric drive unit, and thus the rotary arm 110 can be rotationally driven by an external electric power source or a drive signal.

The image capturing units 121 and 122 are provided at each tip of the first C arm to obtain an image image. Preferably, the image capturing units 121 and 122 include an X-ray source 121 and an X- Ray detector 122 provided opposite to the X-ray detector 121.

The magnetic field generation unit includes a pair of coils 131 and 132 provided at the respective ends of the second C arm so as to face each other and a power supply unit 132 for supplying a magnetizing current for generating an induction magnetic field to the coils 131 and 132 133).

The pair of coils 131 and 132 may be provided by a Helmholtz coil which generates a uniform magnetic field with the same circular coil.

The movable bed 140 is positioned above the support structure 141 and is rotatable about the longitudinal and longitudinal directions. Meanwhile, the movable bed 140 may be provided with a separate electric driving unit, and may be rotated forward or backward by the driving unit.

The catheter feeding unit 200 may control the catheter 10 with the magnetic body. The wire 105 is steered by a magnetic field generated by the pair of coils 131 and 132.

FIG. 2 shows a state in which the catheter 10 according to the embodiment of the present invention is controlled so that the clearance between the bodies 1011, 1013 and 1015 is adjusted by the operation of the wire 105 to enable steering and tunneling. 2A is a longitudinal sectional view in which the flexible wire 1051 is converted into a structure in which the catheter body 101 is steerable by adjusting the plurality of bodies 1011, 1013, and 1015 constituting the catheter body 101 to be spaced apart from each other.

2B shows a state in which the rigid wire 1053 presses the catheter body 101 so that the rigid wire 1053 can be inserted into the catheter body 101 by adjusting the flexible wires 1051 to bind the plurality of bodies 1011, Is a longitudinal cross-sectional view converted into a structure to be transferred.

2, a catheter 10 according to an embodiment of the present invention includes a catheter body 101 inserted into a barrel; And a wire 105 connected to the catheter body 101.

The catheter body 101 may have a plurality of bodies 1011, 1013, and 1015 that can be coupled. The catheter body 101 may be provided with a magnetic body and can be steered by a magnetic field applied from the outside. In this case, the bodies 1011, 1013 and 1015 constituting the catheter body 101 may be made of magnetic material separately or the bodies 1011, 1013 and 1015 themselves may be made of magnetic material.

In the present invention, the magnetic body is not particularly limited as long as it includes permanent magnets and is magnetized in a magnetic field. The process of controlling the direction to the magnetic field can be understood by the catheter system described later.

The wire 105 may be provided by a flexible metal or synthetic resin material in the form of a spring. In this case, the wire 105 may be made of a different material in some sections. The wire 105 may be provided with a proximal end material that is connected to the distal end of the catheter body 101 and a distal end that is connected to the lower end of the catheter body 101. Preferably, the distal portion can be made of a more flexible material compared to the proximal portion. For example, a metal material may be used for the proximal portion, and a synthetic resin material may be used for the distal portion.

The wire 105 may be provided with a structure in which a wire member having a relatively high degree of flexibility is intro- duced into a wire member having a relatively low degree of flexibility as an example in which a material having a different flexibility is provided in a certain section. More specifically, in this embodiment, the wire 105 includes a rigid wire 1053 that presses the catheter body 101; And a flexible wire 1051 which is inserted into the rigid wire 1053 to adjust the clearance between the plurality of bodies 1011, 1013 and 1015.

The flexible wire 1051 may be made of a material having higher flexibility than the rigid wire 1053. The flexible wire 1051 is pulled out of the rigid wire 1053 and connected to the distal end of the catheter body 101, which may correspond to the distal portion of the wire 105 described above. The rigid wire 1053 is connected to the rear end of the catheter body 101 and may correspond to the proximal portion of the wire 105 described above. The coupling relationship between the catheter body 101 and the wire 105 can be clearly understood through the following description.

The catheter body 101 includes a first body 1011 fixedly connected to a distal portion of the wire 105; A second body 1013 provided between the first body 1011 and the third body 1015 and having a through hole 1017 (FIG. 3) through which the wire 105 passes; And a third body 1015 through which the wire 105 penetrates and is fixedly connected to the proximal portion of the wire 105. [

The plurality of bodies 1011, 1013, and 1015 may have a shape that is resistant to external forces in the lateral direction at the time of binding. In this embodiment, the bodies 1011, 1013 and 1015 may be formed with conical tips at their ends. It is preferable that the tip of the first body 1011 is formed to be sharp. The bodies 1011, 1013, and 1015 may be provided in the shape of an arrowhead having a longitudinal section in which both ends of the ends are sloped inward.

The first body 1011 is provided at the distal end of the catheter body 101 and can be fixedly connected to the distal portion of the wire 105 on the underside. In the embodiment of the wire 105 described above, the flexible wire 1051 may be inserted into the lower surface or lower surface of the first body 1011 at a predetermined depth and fixedly coupled.

The second body 1013 is disposed between the first body 1011 and the third body 1015 so that the second body 1013 can be separated or bonded to the first body 1011 and the third body 1015. The flexible wire 1051 penetrates through the through hole 1017 of the second body 1013 and the end of the flexible wire 1051 is fixedly connected to the first body 1011. In this embodiment, the number of the second bodies 1013 may be one or more. The plurality of second bodies 1013 are spaced apart from each other so that the catheter body 101 can be bent when the direction of the vessel is changed. The number of the second bodies 1013 can be appropriately selected according to the curvature required for steering control of the catheter body 101. [

The third body 1015 has a through hole through which the flexible wire 1051 passes and the lower surface of the third body 1015 is fixedly connected to the rigid wire 1053. The flexible wire 1051 is drawn out of the rigid wire 1053 coupled with the third body 1015. The flexible wire 1051 may be fixedly connected to the first body 1011 through the third body 1015 and the second body 1013 sequentially.

Referring to FIG. 2A, the practitioner can adjust the clearance of the bodies 1011, 1013, and 1015 by operating the flexible wire 1051. When the practitioner fixes the rigid wire 1053 and presses the flexible wire 1051, the first body 1011 and the third body 1015 can be separated from each other. In this case, since the wire 105 in the first body 1011 and the second body 1013 has high flexibility, the steering angle of the catheter body 101 can be adjusted by an external magnetic field.

Referring to FIG. 2B, the practitioner can bind the first body 1011, the second body 1013, and the third body 1015 by fixing the rigid wire 1053 and pulling the flexible wire 1051 . According to the above-described embodiment, the bodies 1011, 1013, and 1015 which are in close contact with each other have a structure that is resistant to left and right external forces. 2A, external force is strongly transmitted from the third body 1015 to the first body 1011, and the catheter body 101 receives a strong stiffness for tunneling have.

FIG. 3 is a perspective view showing a combined perspective view of the bodies 1011, 1013, and 1015 and the wire 105 according to the embodiment of the present invention. Referring to FIG. 3, the outer surfaces of the bodies 1011, 1013, and 1015 may be provided in a cylindrical structure having a tapered shape. The end portions of the second body 1013 and the third body 1015 have a tapered structure in which the through hole 1017 is provided so that the flexible wire 1051 penetrates the first body 1013. The first body 1011 has a conical shape A tip may be formed. The flexible wire 1051 may be pulled out of the rigid wire 1053 and sequentially pass through the third body 1015 and the second body 1013 and then be coupled to the first body 1011. [

2 and 3, the flexible wire 1051 having a relatively high flexibility adjusts the plurality of bodies 1011, 1013 and 1015 constituting the catheter body 101 to be spaced apart from each other So that the catheter body can be steered. Further, the flexible wire 1051 adjusts the plurality of bodies 1011, 1013, and 1015 to bind with the catheter inserted into the bar. In this case, since the rigid wire 1053 can transmit rigidity to the catheter body 101, a structure capable of tunneling is provided. Thus, the catheter 10 according to the present invention is a simple structure that is easy to manufacture, and enables steering and tunneling of the catheter body 10 without replacement of the wire 105.

4A shows an assembled perspective view of the body 101 and the wire 105 according to another embodiment of the present invention. FIG. 4B shows a state where the second body 1013 according to FIG. .

Referring to FIG. 4, the body 101 may be provided in a warhead shape. It is preferable that the end of the first body 1011 is formed to be sharply formed for perforation. Unlike the body 101 according to the embodiment of FIG. 3, the second body 1013 and the third body 1015 may be provided in a hemispherical shape. The second bodies 1013 are formed so as to correspond to the hemispherical ends so as to be mutually adhered to each other.

The hemispherical end portions of the second body 1013 and the third body 1015 as in the present embodiment are formed so that when the bodies 1011, 1013, and 1015 are engaged with each other in a state of steering the body, The bodies 1011, 1013, and 1015 can be stuck together while maintaining the bent shape.

5 is a view showing a first embodiment of a catheter feeding unit in a catheter system according to the present invention.

5, the catheter feeding unit 200 includes an F / T sensor unit 220 for detecting a force and a torque applied to the wire 210, And a controller 230 that can vary the induced magnetic field generated by the magnetic field generator according to the signal.

For example, when the catheter 211 is inserted into the blood vessel and contacts the blood vessel wall, the F / T sensor unit 220 detects the reaction force and transmits the detected reaction force to the controller 230, According to the magnitude of the reaction force, the size of the induced magnetic field generated in the magnetic field generating unit is adjusted so that insertion can be performed without damaging the blood vessel wall when the catheter 211 is inserted.

On the other hand, in order to change the steering angle of the tip of the guide wire 210 from the force and torque detected by the F / T sensor unit 220 and the image image obtained by the image pickup unit 121 (122) The rotational angle of the rotary arm 110 can be changed and the direction of the induced magnetic field generated in the magnetic field generating portion can be changed. On the other hand, the control unit 230 may change the steering angle of the catheter 211 by changing the rotation angle of the movable bed 140 separately from the rotation driving of the rotary arm 110.

A wire connection part 221 may be provided between the F / T sensor part 220 and the wire 210, and the wire 210 may be press-fitted into the front end of the wire connection part 221. The reaction force generated by inserting the wire 210 into the human body is transmitted to the F / T sensor unit 220 through the wire connection unit 221 and the supporter 222 capable of supporting the wire connection unit 221 is provided .

The F / T sensor unit 220 is installed in the rotation driving unit 240 and can be rotated by the rotation driving unit 240 to rotate the wire 210. The rotary drive unit may be provided by an electric motor, or a known transmission such as a stepping motor.

The rotation driving unit 240 may include a linear driving unit 250 and may be operated in a forward and backward direction of the wire 210 by linear driving of the linear driving unit 250. The linear driving unit may be a linear motor, May be provided by an actuator.

Reference numeral 201 denotes a base plate on which the catheter feeding unit is installed. The base plate may be a structure provided on the movable bed, or may be a structure provided separately from the movable bed.

6 (a), 6 (b), 6 (c) and 6 (d) illustrate examples of operation of the catheter in a catheter system according to the present invention.

6 (a) and 6 (b), the magnitude of the induced magnetic field differs according to the magnitude of the magnetizing current I1 <I2 applied to the coils 131 and 132. At this time, the magnitude of the steering angle of the catheter corresponds to the magnitude . 5 (c) and 5 (d), the steering direction of the catheter can be changed in accordance with the direction of the magnetizing current applied to the coils 131 and 132.

Figure 7 is a view of another embodiment of a catheter system in accordance with the present invention to be steered. As illustrated in FIG. 6, the wire 210 is capable of steering the catheter body 211 at a large angle by using a material that is more flexible in the distal portion of the material as compared to the proximal portion.

8 (a), 8 (b), 8 (c) and 8 (d) are views for explaining an example of wire operation using the catheter system according to the present invention. The present invention can be performed while monitoring the video image obtained in the video image pickup units 121 and 122 in real time and can be performed in the video image obtained through the video image pickup units 121 and 122, The position of the catheter body and the like can be confirmed.

It is possible to position the guide wire end to the lesion position by appropriately steering the guide wire end along the blood vessel through intensity control and direction control of the magnetizing current applied to the coil while referring to the image of the image. After insertion of the guide wire into the lesion site, the catheter tube may enter the lesion along the guide wire.

The force and the torque detected by the F / T sensor unit 220 in the process of inserting the wire 210 are transmitted to the controller 230. The controller 230 detects the contact between the tip of the wire 210 and the blood vessel wall &Lt; / RTI > The control unit 230 controls the power supply unit 133 to adjust the induced magnetic field generated in the coils 131 and 132 to prevent damage to the blood vessel wall.

On the other hand, when the guide wire is inserted along the blood vessel of a relatively straight section at the time of inserting the wire 210 as shown in FIGS. 8A and 8C, an induction magnetic field does not need to be generated, An induction magnetic field is generated at a position where a direction change of the guide wire is required, so that the guide wire can be steered.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. will be. Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined by all changes or modifications derived from the scope of the appended claims and equivalents of the following claims.

10: catheter 101: catheter body
1011: first body 1013: second body
1015: third body 1017: through hole
105, 210, 310: wire 1051: flexible wire
1053: Rigid wire
110: rotating arm 111: first C arm
112: second C arm 121: X-ray source
122: X-ray detector 131, 132: coil
133: Power supply unit 140: Operation bed
200, 300: catheter feeding unit 211, 311: catheter
220, 320: F / T sensor unit 230, 330:
240: rotation driving part 340: linear-rotation driving part
341: rotation drive module 342: linear drive module
250, 350: linear driving part

Claims

In a catheter capable of steering and tunneling,
A catheter body having a plurality of bodies capable of being tied; And
And a wire connected to the catheter body for regulating the clearance between the plurality of bodies.

The method according to claim 1,
The body
Wherein the magnetic field is steered by a magnetic field externally applied with a magnetic body.

The method according to claim 1,
The wire
Wherein a material of a distal portion connected to a distal end of the catheter body is different from a material of a proximal portion connected to a rear end of the catheter body.

The method according to claim 1,
The catheter body includes:
A first body fixedly connected to the distal portion of the wire;
A second body provided between the first body and the third body and having a through hole through which the wire penetrates; And
Wherein the wire has a third body penetrating therethrough and being fixedly connected to the proximal portion of the wire.

5. The method of claim 4,
Wherein the second body is at least one catheter.

5. The method of claim 4,
The end of the first body is conical in shape with a sharp tip,
Wherein the ends of the second body and the third body are hemispherical.

5. The method of claim 4,
The wire
A rigid wire for pushing the catheter body; And
And a flexible wire inserted into the rigid wire to adjust the clearance between the plurality of bodies.

8. The method of claim 7,
Wherein the flexible wire is made of a material having higher flexibility than the rigid wire.

8. The method of claim 7,
Wherein the rigid wire is fixedly connected to the third body,
Wherein the flexible wire is fixedly connected to the first body through the second body.