CN112971872B

CN112971872B - Propelling movement cable and propelling movement system

Info

Publication number: CN112971872B
Application number: CN201911303906.XA
Authority: CN
Inventors: 张翠茹; 何闵; 陈贤淼
Original assignee: Lifetech Scientific Shenzhen Co Ltd
Current assignee: Lifetech Scientific Shenzhen Co Ltd
Priority date: 2019-12-17
Filing date: 2019-12-17
Publication date: 2022-12-20
Anticipated expiration: 2039-12-17
Also published as: CN112971872A

Abstract

The invention relates to a push cable and a push system. The push cable comprises a first section of metal cable, a second section of metal cable and a connecting piece, wherein the connecting piece comprises a connecting rod, one end of the connecting rod is connected with the first section of metal cable, the other end of the connecting rod is connected with the second section of metal cable, the connecting rod is positioned on the same side of the first section of metal cable and the second section of metal cable, and the ratio of the rod diameter of the connecting rod to the diameter of a circumscribed circle of the second section of metal cable is 1 (8-15) so that the second section of metal cable can bend towards the other side opposite to the connecting rod. The push cable can realize natural bending without mechanical grinding processing.

Description

Propelling movement cable and propelling movement system

Technical Field

The invention relates to the field of interventional medical instruments, in particular to a pushing cable and a pushing system.

Background

This section provides background information related to the present disclosure only and is not necessarily prior art.

With the continuous development of interventional medical devices, catheter-mediated minimally invasive therapy is becoming an important method for treating congenital heart diseases such as Atrial Septal Defect (ASD), ventricular Septal Defect (VSD), patent Ductus Arteriosus (PDA) and Patent Foramen Ovale (PFO).

The interventional medical device is delivered to a human lesion site by a delivery system through catheter interventional minimally invasive therapy. Taking a ventricular septal defect occlusion as an example, a ventricular septal defect occluder is pushed to a desired position by a pushing steel cable during an interventional therapy. One end of the pushing steel cable is connected with the ventricular septal defect occluder, the other end of the pushing steel cable is connected with a handle of the conveying system, and the pushing steel cable plays a key role in the pushing process of the ventricular septal defect occluder.

The existing push cables are generally stainless steel spring tubes, such as 304 stainless steel tubes, 316L stainless steel tubes, etc. The existing stainless steel spring tube has higher hardness and bending rigidity. Due to the complexity of blood vessel diameter and lesion parts in a human body, for blood vessels with larger bending degree or parts which need to be bent to reach, such as ventricular septal defect parts, a conveying system is required to bear larger bending in the conveying process. Thus, it is desirable to have a sheath for use with a delivery system that can be bent at an angle at the head to pass through a curved vessel or to align a defect site, but this bending is particularly difficult due to the relatively high stiffness and bending stiffness characteristics of existing push cables. Especially for the delivery system used in the transcatheter ventricular septal defect occlusion, the operation using the existing stainless steel spring tube will be very challenging due to the greater bending degree of the sheath head, so that the transcatheter ventricular septal defect occlusion is difficult to implement.

Therefore, the head of the push wire rope needs to be softened. At present, a mechanical grinding processing mode is usually adopted for softening treatment, but the processing process consumes labor hour, and inconsistent performance and even poor performance are easily caused by processing errors. The degree of softening is also difficult to meet.

Disclosure of Invention

In view of this, there is a need for a push cable that does not require mechanical grinding operations.

The utility model provides a propelling movement cable, includes first section metal cable, second section metal cable and connecting piece, the connecting piece includes the connecting rod, the one end of connecting rod with first section metal cable links to each other, the other end with second section metal cable links to each other, the connecting rod is located first section metal cable with same one side of second section metal cable, just the pole footpath of connecting rod with the ratio of the diameter of the circumscribed circle of second section metal cable is 1 (1.575 ~ 22.2), makes second section metal cable can the orientation with the opposite side that the connecting rod is relative is crooked.

In one embodiment, the connecting member further comprises at least one wavy annular structure, the connecting rod is connected with the wavy annular structure, and the connecting rod is parallel to the longitudinal central axis of the wavy annular structure.

In one embodiment, when there is one corrugated ring structure, one end of the corrugated ring structure is connected to the first section of metal cable, and the other end of the corrugated ring structure is connected to the second section of metal cable;

when the waveform annular structures are multiple, the waveform annular structures are arranged along the axial direction, one waveform annular structure at one end is connected with the first section of metal cable, one waveform annular structure at the other end is connected with the second section of metal cable, and the connecting rod connects the plurality of waveform annular structures in the axial direction.

In one embodiment, the wave heights of any one of the wavy annular structures are different, and the connecting rod is located on the side of the wavy annular structure where the wave height is larger.

In one embodiment, when there are a plurality of the wavy annular structures, at least part of the wave crests and the wave troughs of any two adjacent wavy annular structures are abutted on the side with larger wave height.

In one embodiment, the wave height of the wavy annular structure gradually decreases from one side to the other side along the circumferential direction; or,

the wave ring structure comprises a first wave structure and a second wave structure connected with the first wave structure, the first wave structure is an equal wave height structure, the second wave structure is an equal wave height structure, and the wave height of the first wave structure is larger than that of the second wave structure.

In one embodiment, the push cable further comprises a protective film, and the protective film at least covers the connection part of the connecting rod and the first section of metal cable and the connection part of the connecting piece and the second section of metal cable.

In one embodiment, the wavy annular structure is directly connected with the first section of metal cable and the second section of metal cable;

or the pushing cable further comprises a protective film, and the first section of metal cable, the connecting piece and the second section of metal cable are sequentially connected along the axial direction through the protective film.

In one embodiment, the ratio of the axial lengths of the first section of metal cable, the connecting rod and the second section of metal cable is 200 (1-12): 24.

In one embodiment, the ratio of the diameters of the circumscribed circle of the first section of metal cable, the wavy annular structure and the second section of metal cable is 1.50 to 1.60.

A pushing system comprises a handle and the pushing cable, wherein one end of the first section of metal cable, which is far away from the second section of metal cable, is connected with the handle.

The first section metal cable and the second section metal cable of above-mentioned propelling movement cable pass through the connecting rod and link to each other, and the connecting rod is located same one side of first section metal cable and second section metal cable to the rod diameter of connecting rod is far less than the diameter of the circumscribed circle of second section metal cable, makes the constraint that receives when the propelling movement cable disappear the back, and second section metal cable can be crooked relatively first section metal cable nature, and it is comparatively easy to bend. Therefore, the push cable can realize natural bending without mechanical grinding processing.

Drawings

FIG. 1 is a schematic diagram of a push system according to an embodiment;

FIG. 2a is a schematic structural view of an embodiment of a push cable in an unbent state;

FIG. 2b is a schematic view of the push cable shown in FIG. 2a in a curved state;

FIG. 3 is a schematic diagram of a first segment of a metal cable according to one embodiment;

FIG. 4 is a schematic structural diagram of a first segment of a metal cable according to one embodiment;

FIG. 5a is a schematic perspective view of a connector according to an embodiment;

FIG. 5b is a schematic view of a partially expanded configuration of the connector shown in FIG. 5;

FIG. 6 is a schematic view of a portion of another embodiment push cable;

FIG. 7 is an enlarged view of a portion of FIG. 5 b;

FIG. 8 is a schematic view of an expanded configuration of a connector according to one embodiment;

fig. 9 is a schematic view showing a developed structure of a link according to another embodiment.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather should be construed as broadly as the present invention is capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

For purposes of more clearly describing the structure of the present invention, the terms "distal" and "proximal" are used as terms commonly used in the art of interventional medical devices, wherein "distal" refers to the end that is distal from the operator during a procedure and "proximal" refers to the end that is proximal to the operator during a procedure.

Referring to FIG. 1, one embodiment of a pusher system 100 includes a handle 20, a pusher cable 40, and an implantable device 60. One end (proximal end) of the push cable 40 is connected to the handle 20, and the implantable device 60 is detachably connected to the end (distal end) of the push cable 40 that is distal from the handle 20. After the implantable device 60 is pushed to the corresponding part in the living body through the handle 20 and the push cable 40, the connection between the push cable 40 and the implantable device 60 is disconnected, and the push cable 40 is withdrawn from the living body, thereby completing the implantation operation.

In one embodiment, the implantable device 60 is a cardiac occluder. It is understood that in other embodiments, the implantable device 60 is not limited to an occluder and may be other devices.

Referring to fig. 2a and 2b, the push cable 40 includes a first metal cable 42, a second metal cable 44 and a connecting member 46, wherein one end of the connecting member 46 is connected to the first metal cable 42, and the other end is connected to the second metal cable 44. With a first length of wire 42 at the proximal end and a second length of wire 44 at the distal end. Fig. 2a shows the push cable 40 in an unbent state, and fig. 2b shows the push cable 40 in a bent state.

In one embodiment, referring to fig. 3, the first length of metal wire 42 is a hollow metal wire formed by a plurality of metal wires 422 spirally wound around a cylindrical mandrel and shaped. In another embodiment, the first length of wire cable 42 is a solid metal cable formed by a plurality of wires 422 helically wound around a cylindrical mandrel and shaped. For example, the first length of metal wire 42 is a hollow or solid nitinol wire formed from a plurality of nitinol wires helically wound around a cylindrical mandrel and shaped.

Alternatively, referring to fig. 4, the first length of wire cable 42 is a hollow metal tube formed by a single wire 424 helically wound and shaped.

In one embodiment, the second length of wire cable 44 is a hollow or solid wire cable formed by helically winding a plurality of wires around a cylindrical mandrel and shaping, or a hollow metal tube formed by helically winding a single wire and shaping. For example, the second length of metal cable 44 is a hollow or solid nitinol cable formed by helically winding a plurality of nitinol wires around a cylindrical mandrel and shaping the nitinol wires.

The first and second lengths of

metal wire

42, 44 are helically wound in the manner described above such that the first and second lengths of

metal wire

42, 44 have sufficient push force to meet the push requirement. At the same time, the first and second lengths of

metal wire

42, 44 are sufficiently compliant to allow the push cable 40 to smoothly pass through a tortuous vascular passageway of a living being.

In one embodiment, the first metal cable 42 and the second metal cable 44 are both solid cables or both hollow cables. In one embodiment, one of the first and second lengths of

metal cable

42, 44 is a solid cable and the other is a hollow cable.

In an embodiment, the diameters of the circumscribed circles of the first section of metal cable 42 and the second section of metal cable 44 are both 1.0-4.5 mm, and the first section of metal cable 42 and the second section of metal cable 44 are both hollow nickel-titanium cables formed by winding 6-10 nickel-titanium wires with the wire diameter of 0.36-0.50 mm around a cylindrical mandrel with the diameter of 0.85mm, so as to ensure that the first section of metal cable 42 and the second section of metal cable 44 have sufficient pushing force and flexibility, and simultaneously avoid that the circumscribed circles of the first section of metal cable 42 and the second section of metal cable 44 are not too large, thereby avoiding the need to increase the size of the conveying sheath to adapt to the too large pushing cable 40, which results in difficulty in conveying.

In one embodiment, the equivalent bending stiffness of the first length of metal cable 42 is greater than the equivalent bending stiffness of the second length of metal cable 44, making the distal end of the pusher cable 40 softer to facilitate passage through a tortuous vascular pathway.

In one embodiment, the first and second lengths of

metal wire

42, 44 are the same material and have the same structure, and the diameter of the circumscribed circle of the first length of metal wire 42 is greater than the diameter of the circumscribed circle of the second length of metal wire 44, so that the equivalent bending stiffness of the first length of metal wire 42 is greater than the equivalent bending stiffness of the second length of metal wire 44.

Referring to fig. 5a and 5b, the connecting member 46 includes a corrugated loop structure 462. In the embodiment shown in fig. 5 and 5b, the wavy annular structure 462 is plural, and the plural wavy annular structures 462 are arranged in the axial direction. In one embodiment, two corrugated loops 462 at each end are connected to the first and second lengths of

wire

42 and 44, respectively, as shown in FIG. 6.

In one embodiment, the number of the wavy annular structures 462 is 2 to 4, so that the second metal cable 44 can be smoothly bent and the pushing cable 40 has a sufficient pushing force.

In one embodiment, there is one corrugated annular structure 462. Opposite ends of a corrugated loop structure 462 are connected to the first and second lengths of

wire

42 and 44, respectively.

Whether the number of the wavy annular structures 462 is one or more, the wave heights of the wavy annular structures 462 are different so that the second-segment metal cable 44 can be naturally bent toward the side of the wavy annular structures 462 (as shown in fig. 2 b) where the wave heights are smaller, and the bending is easy. Thus, the push cable 40 can achieve natural bending without mechanical grinding. The preparation efficiency is high, the reliability is high, the woven structure cannot be scattered and separated, and the problems of inconsistent product performance and even poor performance caused by machining errors can be solved.

In one embodiment, referring to fig. 7, the wave height of the wave-shaped annular structure 462 gradually decreases from one side to the other side along the circumferential direction (as indicated by four wave heights H1, H2, H3, and H4, H1> H2> H3> H4), so that the second section of the metal cable 44 can naturally bend toward the side of the wave height of the wave-shaped annular structure 462.

In one embodiment, referring to fig. 8, the wavy annular structure 462 includes a first wavy structure 462A and a second wavy structure 462B connected to the first wavy structure 462A. The first waved structure 462A is an equi-wave height structure, the second waved structure is also an equi-wave height structure, and the wave height of the first waved structure 462A is greater than the wave height of the second waved structure 462B (i.e., H5> H6), so that the second metal cable 44 can be naturally bent toward the side of the waved ring structure 462 with smaller wave height, i.e., toward the side where the second waved structure 462B is located.

In one embodiment, whether the wave height of the wave-shaped annular structure 462 gradually decreases from one side to the other side along the circumferential direction or the wave-shaped annular structure 462 has two unequal wave heights, at least a part of wave crests and wave troughs of any two adjacent wave-shaped annular structures 462 are in contact with each other on the side with the larger wave height (as shown in fig. 9), so that the connecting member 46 has better rigidity to meet the pushing requirement.

It can be understood that at least a part of the wave crests and wave troughs of the two wave-shaped ring structures 462 are abutted, that is, the wave crests and the wave troughs with larger wave heights are abutted to improve the rigidity, and the wave-shaped ring structures 462 are not influenced to bend to the side with smaller wave heights.

In one embodiment, referring back to fig. 5, the connector 46 further includes a connecting rod 464, the connecting rod 464 axially connecting the plurality of undulating annular structures 462. The connecting rod 464 is located on one side of the wavy annular structure 462, and the connecting rod 464 is parallel to the longitudinal central axis of the wavy annular structure 462. The connecting rod 464 is connected with the plurality of wave-shaped annular structures 462, so that the overall rigidity of the pushing cable 40 is improved, and the pushing is facilitated. The connecting rod 464 is located on the side of the wavy annular structure 462 where the wave height is large so as not to affect the second-stage metal cable 44 to be able to naturally bend toward the side of the wavy annular structure 462 where the wave height is small. The ratio of the rod diameter of the connecting rod 464 to the diameter of the circumscribed circle of the second section of metal cable 44 is 1 (1.575-22.2), so that the second section of metal cable 44 is easier to bend relative to the first section of metal cable 42.

In one embodiment, the connecting rods 464 are located on the outer surface of the undulating annular structure 462. In another embodiment, the connecting rods 464 are located in the lumen of the undulating annular structure 462.

In one embodiment, the connecting rods 464 are straight rod structures, with one connecting rod 464 extending from the distal end to the proximal end of the connector 46 and connecting a plurality of axially aligned undulating annular structures 462. In one embodiment, the connecting rod 464 extends from the distal end to the second length of metal cable 44 and is fixedly connected to the second length of metal cable 44. The connecting rod 464 extends from the proximal end to the first length of metal cable 42 and is fixedly connected to the first length of metal cable 42. This arrangement is advantageous in further improving the pushing force of the pushing cable 40.

In one embodiment, the ratio of the length of the portion of the connecting rod 464 extending to the second length of metal cable 44 to the length of the second length of metal cable 44 is 1:5-1 to provide both the overall pushing force and the compliance of the second length of metal cable 44. The ratio of the length of the portion of the connecting rod 464 extending to the first length of metal cable 42 to the length of the first length of metal cable 42 is 1:8-1, so as to take into account the overall pushing force and the flexibility of the first length of metal cable 44.

In one embodiment, when the wave bars of the wavy annular structure 462 are unequal, the connecting bar 464 is located on the side of the wavy annular structure 462 where the wave height is greater.

It should be noted that in one embodiment, the wavy annular structure 462 may be omitted, and the connecting rod 464 of the connecting member 46 has one end connected to the first metal wire 42 and the other end connected to the second metal wire 44. Omitting the undulating ring structure 462 allows the push cable 40 to be more flexible overall, facilitating smooth passage through tortuous vascular pathways. The wavy annular structure 462 can support the connecting rod 464 to a certain degree, and is beneficial to avoiding the connecting rod 464 from bending excessively.

In one embodiment, both the first length of metal cable 42 and the second length of metal cable 44 are hollow cables. Moreover, the portion of the connecting rod 464 extending to the first section of metal cable 42 is located in the inner cavity of the first section of metal cable 42, and the portion of the connecting rod 464 extending to the second section of metal cable 44 is located in the inner cavity of the second section of metal cable 44, so that the outer surface of the push cable 40 is relatively smooth, and the portion of the connecting rod 464 extending to the first section of metal cable 42 and the portion extending to the second section of metal cable 44 are prevented from scratching tissues in the surgical procedure.

It is understood that in other embodiments, the connecting rod 464 is not limited to a straight rod structure and may be any shape of rod-like structure. For example, in one embodiment, the connecting rod 464 is a wavy rod-like structure.

In one embodiment, the connecting rod 464 comprises a plurality of discrete segments, each segment connecting two adjacent undulating annular structures 462. Thus, the pushing force can be increased without affecting the bending of the second metal cable 44 toward the side of the wavy annular structure 462 with lower wave height.

In one embodiment, the two segments of the connecting rod 464 are located at two ends, one segment connecting the proximal wavy annular structure 462 and the first length of metal cable 42, and the other segment connecting the distal wavy annular structure 462 and the second length of metal cable 44.

In one embodiment, the first and second lengths of

metal wire

42 and 44 are both hollow wires, the proximal end corrugated loop 462 and the segment portion of the first length of metal wire 42 are received in the lumen of the first length of metal wire 42, and the segment portion connecting the distal corrugated loop 462 and the second length of metal wire 44 are received in the lumen of the second length of metal wire 44.

In one embodiment, referring again to FIG. 6, the push cable 40 further includes a spring module 48. The protective film 48 covers at least the connection surface of the connector 46 and the first metal wire 42 and the connection surface of the connector 46 and the second metal wire 44.

The protective film 48 is provided to make the connection portion between the first section of metal cable 42 and the connecting member 46 and the connection portion between the second section of metal cable 44 and the connecting member 46 smoother, so as to avoid scratching the tissue. The protective film 48 is made of a polymer material with good biocompatibility and high mechanical strength. In one embodiment, the material of the protective film 48 is silicon rubber, polyurethane material, or polytetrafluoroethylene material.

The protective film 48 may cover only the connection portion between the first metal wire 42 and the connector 46 and the connection portion between the second metal wire 44 and the connector 46, or may completely cover the first metal wire 42, the second metal wire 44, and the connector 46. Alternatively, in another embodiment, the protective film 48 completely covers the connection portion between the first metal cable 42 and the connector 46 and the connection portion between the second metal cable 44 and the connector 46, and completely covers the second metal cable 44.

During operation, for example, in the implantation operation of the ventricular septum heart occluder, at least a part of the second section of metal cable 44 enters the heart, and the protective film 48 completely covers the second section of metal cable 44, which is beneficial to avoiding damage to the heart tissue. The protective film 48 completely covers the first length of metal cable 42, the second length of metal cable 44, and the connector 46, which is beneficial for avoiding tissue damage, such as vascular tissue damage and cardiac tissue damage, during the entire delivery process.

In one embodiment, the thickness of the protective film 48 is 0.01 to 0.4 mm. The thickness of the protective film 48 is set within this range, on one hand, the influence on the conveying due to the overlarge radial size of the push cable 40 is avoided, and on the other hand, the protective film 48 provides a better protective effect and avoids tissue damage.

In one embodiment, the first length of metal cable 42 is not directly connected to the connector 46, the second length of metal cable 44 is not directly connected to the connector 46, and the first length of metal cable 42, the connector 46 and the second length of metal cable 44 are connected by the protective film 48.

In one embodiment, the protection film 48 is an elastic film, so that the protection film 48 can adapt to the bending of the connecting member 46 and can be bent along with the bending of the connecting member 46 without interfering with the bending of the connecting member 46, thereby facilitating the smooth operation.

In one embodiment, the ratio of the axial lengths of the first length of metal cable 42, the connecting rod 464, and the second length of metal cable 44 is 200 (1-12): 24 to account for push and compliance requirements.

In one embodiment, the diameter ratio of the circumscribed circle of the first, wave-shaped

annular structures

42, 462 and the second segment of metal wire 44 is 1.50-1.60, 1.0-1.60, and the wave-shaped annular structures 462 are formed from wire having a wire diameter of 0.05-0.2 mm to allow for push and compliance requirements and to provide a smaller delivery sheath size.

In one embodiment, the diameter of the circumscribed circle of the first length of wire 42 is 1.56 mm, the diameter of the circumscribed circle of the second length of wire 44 is 1.32 mm, and the diameter of the circumscribed circle of the undulating annular structure 462 is any number within the range of 1.32 to 1.56.

The first section of metal cable 42 and the second section of metal cable 44 of the above-mentioned propelling movement cable 40 are connected through the connecting rod 464, and the connecting rod 464 is located the same side of the first section of metal cable 42 and the second section of metal cable 44, and the rod diameter of the connecting rod 464 is far less than the diameter of the circumscribed circle of the second section of metal cable 44, so that after the constraint that the propelling movement cable 40 received disappears, the second section of metal cable 44 can be bent naturally relative to the first section of metal cable 42, and the bending is easy. The push cable 40 can be naturally bent without performing mechanical grinding. The operation of the pushing system 100 is convenient.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is specific and detailed, but not to be understood as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A push cable is characterized by comprising a first section of metal cable, a second section of metal cable and a connecting piece, wherein the connecting piece comprises a connecting rod, one end of the connecting rod is connected with the first section of metal cable, the other end of the connecting rod is connected with the second section of metal cable, the connecting rod is positioned on the same side of the first section of metal cable and the second section of metal cable, and the ratio of the rod diameter of the connecting rod to the diameter of a circumscribed circle of the second section of metal cable is 1 (1.575-22.2), so that the second section of metal cable can bend towards the other side opposite to the connecting rod;

the connecting piece still includes at least one wave form ring structure, the connecting rod with wave form ring structure connects, arbitrary one wave height of wave form ring structure varies, just the connecting rod is located the great one side of wave height of wave form ring structure.

2. Push cable according to claim 1, characterised in that said connecting rods are parallel to the longitudinal central axis of said wavy annular structure.

3. The push cable according to claim 2, wherein when said corrugated annular structures are one, said corrugated annular structures are connected at one end to said first length of metal wire and at the other end to said second length of metal wire;

4. Push cable according to claim 1, characterised in that when a plurality of said undulating annular structures are present, at least some of the peaks and troughs of any two adjacent undulating annular structures abut on the side of greater wave height.

5. Push cable according to claim 1, characterised in that the wave height of the wavy annular structure decreases progressively from one side to the other in the circumferential direction; or,

6. The push cable according to claim 1, further comprising a protective film covering at least a connection portion of the connection rod and the first section of metal cable and a connection portion of the connection member and the second section of metal cable.

7. The push cable of claim 2, wherein the wavy annular structure is directly connected to the first and second lengths of metal wire;

8. The push cable of claim 1, wherein the ratio of the axial lengths of the first length of metal cable, the connecting rod and the second length of metal cable is 200 (1-12): 24.

9. The push cable according to claim 2, wherein the ratio of the diameters of the circumscribed circles of said first section of metal cable, (1.50-1.60), (1.0-1.32) and said corrugated annular structure is formed by wires having a wire diameter of 0.05-0.2 mm.

10. A push system comprising a handle, and further comprising the push cable of any one of claims 1-9, wherein the end of the first length of metal cable distal from the second length of metal cable is attached to the handle.