CN217612407U - Adjustable bent sheath - Google Patents

Abstract

The utility model discloses an adjustable bending sheath tube, which comprises a far-end tube body and a main body tube body, wherein a first accommodating cavity and a first traction wire cavity are arranged in the far-end tube body at intervals, and the first accommodating cavity axially penetrates through the far-end tube body; the main body pipe body is connected to the near end of the far-end pipe body, a second accommodating cavity which axially penetrates through the main body pipe body is arranged in the main body pipe body, and an inner channel is arranged in the second accommodating cavity; the part of the traction wire positioned in the far-end tube body movably penetrates through the first traction wire cavity, and the part of the traction wire positioned in the main body tube body movably penetrates through the inner channel; wherein, the first chamber and the first wire chamber that draws all holds the chamber intercommunication with the second, and the first internal diameter that holds the chamber is less than the second and holds the internal diameter in chamber for the wire that draws is unsettled in main part shaft. According to the utility model discloses an adjustable curved sheath pipe, the traction wire is unsettled in the main part shaft, and the main part shaft is hardly stressed to avoid adjustable curved sheath pipe "humpback" phenomenon to appear.

Description

Adjustable bent sheath tube

Technical Field

The utility model belongs to the field of medical equipment, particularly, relate to an adjustable curved sheath pipe.

Background

With the continuous development of interventional therapy, the adjustable bending sheath tube with various structures is widely used in clinical diagnosis or treatment, and medicines or instruments for treatment are accurately delivered to the position of a lesion by adjusting the bending angle of the distal end of the adjustable bending delivery sheath tube.

The curved sheath pipe of current adjustable can draw the silk chamber and wholly hold the traction wire in the traction wire intracavity along the axial setting in the pipe wall of body usually, and the distal end at the body is fixed to the distal end of traction wire, and the proximal end of traction wire is connected to the handle of body proximal end, and the operator passes through operating handle, and the tractive traction wire drives the body of sheath pipe distal end and bends to different angles, realizes the "adjustable curved" function of body. However, in the bending process of the adjustable bending sheath catheter, the traction wire cavity is continuously penetrated and laid in the inner wall of one side of the sheath catheter body, when the traction wire is pulled, the traction wire cavity is subjected to the acting force of the traction wire, pressure is generated on the catheter wall to force the catheter body to be bent, so that all the catheter body sections containing the traction wire cavity can be bent, the whole catheter body can have a humpback phenomenon, namely the whole catheter body is not straight, and can be bent to different degrees, as shown in fig. 1, the normal use and the operation process of the adjustable bending catheter can be seriously influenced.

In view of the above problems, the prior art also discloses an adjustable bending sheath tube with gradually increasing hardness from the distal end to the proximal end of the tube body, which resists the bending through the proximal end tube body with higher hardness, but this will cause the acting force to be accumulated on the side where the traction wire is laid by the tube body, and because the cross section of the tube wall of the sheath tube is not completely regular, there is a part with uneven thickness, which is easy to interfere with the traction of the traction wire, and finally the force applied to the traction wire on the circumference is anisotropic, so that when an operator twists the proximal end tube body, the whole tube body cannot be twisted synchronously, which not only can not improve the "humpback" phenomenon of the tube body well, but also can cause the pulling force loss in the tube body, and reduce the sensitivity of the bending process.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problem that exists among the prior art, the utility model provides an adjustable curved sheath pipe, it includes:

the medical tube comprises a far-end tube body and a main tube body, wherein a first accommodating cavity and a first traction wire cavity are arranged in the far-end tube body at intervals, the first accommodating cavity axially penetrates through the far-end tube body, the main tube body is connected to the near end of the far-end tube body, a second accommodating cavity axially penetrates through the main tube body is arranged in the main tube body, and an internal channel is arranged in the second accommodating cavity;

the part of the traction wire positioned in the far-end tube body movably penetrates through the first traction wire cavity, and the part of the traction wire positioned in the main body tube body movably penetrates through the inner channel;

wherein, the first chamber and the first wire chamber that draws all holds the chamber intercommunication with the second, and the first internal diameter that holds the chamber is less than the second and holds the internal diameter in chamber for the wire that draws is unsettled in main part shaft.

Compared with the prior art, the utility model provides an adjustable bent sheath catheter, the pull wire in the main body tube body is suspended and not integrated with the main body tube body, when the distal end tube body is controlled to be bent through the pull wire, the acting force can not be transmitted and pressed to the main body tube body, the main body tube body is hardly stressed, so that the main body tube body is kept straight and has better bending resistance, and the phenomenon of humpback of the adjustable bent sheath catheter is avoided; meanwhile, the main pipe body does not need to be hardened gradually, so that the traction tension loss can be avoided, and the flexibility of the bending adjusting process is improved.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present invention and, together with the description, serve to explain the principles of the invention.

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive labor.

FIG. 1 illustrates the "humpback" phenomenon of an adjustable curved sheath in the prior art;

fig. 2 illustrates a perspective view of an adjustable bending sheath according to certain embodiments of the present invention;

FIG. 3 is an enlarged view at D of FIG. 2;

fig. 4 shows a schematic diagram of the bendable sheath according to some embodiments of the present invention in a bending state;

fig. 5 illustrates a perspective view of an adjustable bending sheath according to some embodiments of the present invention;

fig. 6 illustrates a cross-sectional view of an adjustable bend sheath according to certain embodiments of the present invention;

fig. 7 illustrates an exploded view of an adjustable bend sheath according to certain embodiments of the present invention;

fig. 8 illustrates a perspective view of an adjustable bend sheath according to certain embodiments of the present invention;

FIG. 9 isbase:Sub>A cross-sectional view taken at A-A of FIG. 8;

FIG. 10 is a cross-sectional view at B-B of FIG. 8;

fig. 11 illustrates an overall exploded view of an adjustable bend sheath according to certain embodiments of the present invention;

fig. 12 shows a schematic structural view of a bendable sheath according to some embodiments of the present invention;

fig. 13 is a schematic structural view of the channel tube and the first and second positioning rings of the bendable sheath according to some embodiments of the present invention;

fig. 14 is a schematic view of the inner liner tube, the passage tube, the first positioning ring and the second positioning ring of the sheath tube according to some embodiments of the present invention;

FIG. 15 is an enlarged view at E in FIG. 14;

fig. 16 illustrates an exploded view of an adjustable bend sheath according to some embodiments of the present invention.

Detailed Description

In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "inner", "outer", "axial", "radial", "circumferential", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.

As shown in fig. 2 to 3, the bendable sheath 1 according to some embodiments of the present invention includes a distal shaft 10, a main body shaft 20, and a pull wire 30. Optionally, the adjustable bending sheath 1 includes a handle assembly, the proximal end of the main body tube 20 is connected to the handle assembly, and an operator can operate the handle assembly to realize remote control of bending, twisting, axial movement and the like of the adjustable bending sheath 1 outside the patient body.

As shown in fig. 4, in some embodiments, the adjustable bending sheath 1 further includes a proximal shaft 40, and the proximal end of the proximal shaft 40 is connected to a handle assembly, so that an operator can remotely control the adjustable bending sheath 1 by operating the handle assembly to bend, twist, and move axially, etc. outside the patient.

Specifically, as shown in fig. 5-10, a first accommodating cavity 11 and a first traction wire cavity 12 are arranged at intervals in the distal tube body 10, and the first accommodating cavity 11 axially penetrates through the distal tube body 10; the main body tube body 20 is connected to the proximal end of the distal tube body 10, a second accommodating cavity 21 axially penetrating through the main body tube body 20 is arranged in a tube body 23 of the main body tube body 20, and an inner channel 22 is arranged in the second accommodating cavity 21; the portion of the pull wire 30 located in the distal shaft 10 is movably disposed through the first pull wire lumen 12, and the portion of the pull wire 30 located in the main body shaft 20 is movably disposed through the inner passage 22; wherein, first chamber 11 and the first wire chamber 12 that holds all holds 21 intercommunications with the second, and the internal diameter that the first internal diameter that holds 11 is less than the second internal diameter that holds 21 of chamber for pull wire 30 is unsettled in main part shaft 20 and is set up.

The flexibility of the far-end tube body 10 is high, and the tube body can be bent, so that bending adjustment is facilitated; the main body tube body 20 has a high hardness and a substantially flat state, and thus has a strong supporting property. The distal end of the pull wire 30 is fixedly connected to the distal shaft 10 and extends within the first pull wire lumen 12, and the pull wire 30 is used to adjust the distal shaft 10 to bend in different directions.

Because the part movably of haulage wire 30 that is located main part shaft 20 wears to locate in through passageway 22, interior through passageway 22 plays direction and spacing effect to haulage wire 30, make the haulage wire 30 of wearing the dress in main part shaft 20 unsettled, haulage wire 30 and main part shaft 20 looks mutual separation promptly, haulage wire 30 unsettled setting in main part shaft 20, when haulage wire 30 tractive distal end shaft 10, the effort can not transmit and oppress main part shaft 20, main part shaft 20 is hardly stressed, thereby improve main part shaft 20's anti bending property, avoid the body of adjustable curved sheath pipe 1 to appear "hunchback" phenomenon.

In addition, when the operator twists the proximal end of the adjustable bending sheath 1, the pulling force of the pulling wire 30 is mainly transmitted to the distal tube body 10, the pulling force of the pulling wire 30 is not lost in the main tube body 20, and the whole main tube body 20 can smoothly realize synchronous twisting, so that the bending sensitivity of the distal tube body 10 is improved, and the adjustable bending sheath 1 can be applied to a blood vessel with a larger bending angle, such as an aortic arch.

The first receiving cavity 11 and the second receiving cavity 21 are used for an interventional instrument to pass through. Optionally, the difference between the inner diameter of the first accommodating cavity 11 and the inner diameter of the second accommodating cavity 21 is larger than the wire diameter of the pull wire 30, so that the pull wire 30 is prevented from being extruded in the inner channel 22 and can freely slide, and a cutting effect on the pull wire 30 is avoided; the difference value of the inner diameter of the first accommodating cavity 11 and the inner diameter of the second accommodating cavity 21 is smaller than or equal to 2 times of the wire diameter of the traction wire 30, so that the traction wire 30 is limited and guided by the step generated by the difference of the inner diameters, the phenomenon that the transmission torque of the main body tube body 20 is affected due to the fact that the movable space of the traction wire 30 is too large is avoided, and the bending adjusting efficiency of the far-end tube body 10 is improved.

Optionally, the bending-adjustable sheath tube 1 further includes a fixing ring 63, the fixing ring 63 is embedded in the tube wall of the distal tube body 10, and the distal end of the traction wire 30 is fixedly connected to the fixing ring 63 through welding, fusing, bonding, and the like, so that the fixing ring 63 is pulled by controlling the traction wire 30 to drive the distal tube body 10 to bend in different directions.

Optionally, a proximal shaft 40 is attached to the proximal end of the main body 20, and a third receiving lumen 41 and a second pull wire lumen 42 are provided in the proximal shaft 40, the third receiving lumen 41 extending axially through the proximal shaft 40, and a portion of the pull wire 30 located within the proximal shaft 40 is movably disposed through the second pull wire lumen 42. Wherein, the third holds chamber 41 and the second and draws silk chamber 42 and all holds the chamber 21 intercommunication with the second, and the third holds the internal diameter that the chamber 41 is less than the second and holds the internal diameter of chamber 21 for the pull wire 30 is unsettled to be set up in main part shaft 20, makes the pull wire 30 when the tractive distal end shaft 10, and main part shaft 20 is the stress-free hardly, can avoid the body of adjustable curved sheath pipe 1 to appear "hunchback" phenomenon. It should be noted that, overall, the entire pull wire 30 threading path extends axially through the first pull wire lumen 12, the interior passage 22, and the second pull wire lumen 42 in that order until reaching the proximal end of the proximal shaft 40.

Optionally, the difference between the inner diameter of the third accommodating cavity 41 and the inner diameter of the second accommodating cavity 21 is larger than the wire diameter of the pull wire 30, so that the pull wire 30 is prevented from being extruded in the inner channel 22 and can freely slide, and a cutting effect on the pull wire 30 is avoided; the difference value of the inner diameter of the third accommodating cavity 41 and the inner diameter of the second accommodating cavity 21 is less than or equal to 2 times of the wire diameter of the traction wire 30, so that the traction wire 30 is limited and guided by the step generated by the difference of the inner diameters, the phenomenon that the transmission torque of the main body tube body 20 is influenced due to the fact that the movable space of the traction wire 30 is too large is avoided, and the bending adjusting efficiency of the far-end tube body 10 is improved.

Optionally, the first accommodating cavity 11, the second accommodating cavity 21 and the third accommodating cavity 41 are substantially coaxial, so as to facilitate smooth passage of the interventional instrument; the first traction wire cavity 12, the inner channel 22 and the second traction wire cavity 42 are substantially coaxial, so that the traction wire 30 penetrating through the main body tube body 20 can conform to the tube body, stress concentration is reduced, and the phenomenon that the traction wire 30 is displaced due to the fact that the main body tube body 20 is twisted in a skew mode in the bending adjusting process to influence the integral bending adjusting effect of the bending adjustable sheath tube 1 is avoided.

Optionally, as shown in fig. 11 and 12 in combination, the adjustable bending sheath 1 further includes a passage tube 50 at least partially accommodated in the inner through passage 22, and an outer diameter of the passage tube 50 is slightly smaller than an inner diameter of the inner through passage 22. The passage tube 50 is used for accommodating the traction wire 30, thereby protecting and isolating the traction wire 30, separating the traction wire 30 from the main body tube body 20, preventing the interventional instrument threaded in the second accommodating cavity 21 from being entangled with the traction wire 30, and simultaneously enabling the traction force of the traction wire 30 to be directly transmitted to the distal tube body 10.

Optionally, the access tube 50 extends from the distal shaft 10 to the proximal shaft 40, or only from the main body shaft 20 to the proximal shaft 40, with the access tube 50 remaining suspended within the main body shaft 20. The arrangement can ensure that the traction wire 30 is suspended in the main body pipe body 20, and meanwhile, the structural diversity of the channel pipe 50 is increased. Specifically, the passage tube 50 may extend from the distal end of the distal tube body 10 to the proximal end of the proximal tube body 40, or may extend only from the distal end of the main tube body 20 to the proximal end of the main tube body 20, and the passage tube 50 and the tube body of the adjustable bending sheath tube 1 are separated from each other, so that the pulling force of the pulling wire 30 is directly transmitted to the main tube body 20. The channel tube 50 may be made of a metal material such as stainless steel or nickel titanium, or a polymer material with high hardness such as polyimide or polyetheretherketone, so that the pull wire 30 is not easily deformed and kept straight, and the pull wire 30 has a sufficient suspension space.

Optionally, as shown in fig. 9 to 12, the adjustable bending sheath 1 further includes a lining tube 60, the lining tube 60 is inserted into the first accommodating cavity 11, the second accommodating cavity 21, and the third accommodating cavity 41, an outer wall of the lining tube 60 is closely attached to an inner wall of the first accommodating cavity 11 and an inner wall of the third accommodating cavity 41, respectively, and a gap is formed between the outer wall of the lining tube 60 and the inner wall of the second accommodating cavity 21, so that the pull wire 30 is suspended outside the lining tube 60 in the tube body 23 of the main body tube body 20. The inner lining tube 60 extends from the proximal end to the distal end of the adjustable bending sheath tube 1, so that the adjustable bending sheath tube 1 has an integral smooth and uniform inner channel, and the inner cavity of the inner lining tube 60 is the inner cavity of the whole adjustable bending sheath 1 for the interventional instrument to smoothly pass through. As shown in fig. 9, the outer wall of the lining tube 60 is closely attached to the inner wall of the first accommodating cavity 11, so that the portion of the pull wire 30 in the distal shaft 10 is integrally bonded to the distal shaft 10 and the lining tube 60, and similarly, the outer wall of the lining tube 60 is also closely attached to the inner wall of the third accommodating cavity 41, and the portion of the pull wire 30 in the proximal shaft 40 is integrally bonded to the proximal shaft 40 and the lining tube 60, so that the distal shaft 10, the lining tube 60 and the proximal shaft 40 can be tightly connected. As shown in fig. 10, a gap is formed between the outer wall of the inner liner tube 60 and the inner wall of the second accommodating cavity 21, so that the pull wire 30 is suspended in the main body tube 20 and disposed outside the inner liner tube 60, and the pull wire 30 is separated from the inner liner tube 60 and the tube body 23 of the main body tube 20, so that the pull wire 30 does not directly press the main body tube 20, and the suspended pull wire 30 in the main body tube 20 can flexibly control the bending of the distal tube 10 and can transmit torque well.

Alternatively, referring to fig. 11-16, the inner liner tube 60 is sleeved with a first positioning ring 61 and a second positioning ring 62, the first positioning ring 61 is connected with one end of the channel tube 50, the second positioning ring 62 is connected with the other end of the channel tube 50, and the channel tube 50 can be fixed on the inner liner tube 60 by the first positioning ring 61 and the second positioning ring 62. The fixing means of the first positioning ring 61 and the second positioning ring 62 to the passage pipe 50 include welding, fusion welding, and adhesion.

Alternatively, referring to fig. 6, 11 and 12, the tube body 23 of the main tube body 20 comprises a first inner layer 232, a first reinforcing layer 234 and a first outer layer 236 arranged from inside to outside, and the main tube body 20 is connected to the distal tube body 10 and/or the proximal tube body 40 through the first reinforcing layer 234. In order to ensure safe loading and release of the interventional device, the first inner layer 232 should be made of a biocompatible polymer material, such as e-PTFE, so as to ensure that the inner surface of the first inner layer 232 is smooth. The first reinforcing layer 234 is used to increase the strength of the main tube body 20, so that the main tube body 20 can penetrate into the living body with enough hardness, therefore, the first reinforcing layer 234 can be made of metal material, such as stainless steel or nickel-titanium alloy, and can be in the form of woven mesh or spring or cut mesh tube; the first outer layer 236 is directly contacted with the body fluid in the living body and partially needs to be bent, so the first outer layer 236 can be made of thermoplastic elastomer with better biocompatibility, such as Pebax.

Optionally, as shown in fig. 11 and 12, the tubular bodies of the distal tubular body 10 and/or the proximal tubular body 40 each include a second inner layer 132, a second reinforcing layer 134, and a second outer layer 136 that are sequentially disposed from inside to outside, and the second inner layer 132, the second reinforcing layer 134, and the second outer layer 136 of the distal tubular body 10 and/or the proximal tubular body 40 are the same as the corresponding layers of the main tubular body 20, and are not described herein again. Preferably, the second reinforcing layer 134 of the distal shaft 10 and/or the proximal shaft 40 and the first reinforcing layer 234 of the main body shaft 20 are integrally formed, so as to improve the connection strength between the sections of the flexible sheath 1 and to transmit torque more easily.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims (12)

1. An adjustable bend sheath, comprising:

the medical tube comprises a far-end tube body and a main tube body, wherein a first accommodating cavity and a first traction wire cavity are arranged in the far-end tube body at intervals, the first accommodating cavity axially penetrates through the far-end tube body, the main tube body is connected to the near end of the far-end tube body, a second accommodating cavity axially penetrates through the main tube body is arranged in the main tube body, and an internal channel is arranged in the second accommodating cavity;

the part of the traction wire positioned in the far-end tube body is movably arranged in the first traction wire cavity in a penetrating way, and the part of the traction wire positioned in the main tube body is movably arranged in the inner channel in a penetrating way;

the first containing cavity and the first traction wire cavity are communicated with the second containing cavity, and the inner diameter of the first containing cavity is smaller than that of the second containing cavity, so that the traction wire is arranged in the main body pipe body in a suspending mode.

2. The adjustable bending sheath of claim 1, wherein the difference between the inner diameter of the first containing cavity and the inner diameter of the second containing cavity is larger than the wire diameter of the traction wire and smaller than or equal to 2 times the wire diameter of the traction wire.

3. The adjustable bend sheath of claim 1, further comprising:

the proximal tube body is connected to the proximal end of the main tube body, a third accommodating cavity and a second traction wire cavity are arranged in the proximal tube body at intervals, the third accommodating cavity axially penetrates through the proximal tube body, and the part of the traction wire in the proximal tube body movably penetrates through the second traction wire cavity;

the third accommodating cavity and the second traction wire cavity are communicated with the second accommodating cavity, and the inner diameter of the third accommodating cavity is smaller than that of the second accommodating cavity, so that the traction wires are suspended in the main body pipe body.

4. The adjustable bending sheath tube of claim 3, wherein the difference between the inner diameter of the third accommodating cavity and the inner diameter of the second accommodating cavity is larger than the wire diameter of the traction wire and smaller than or equal to 2 times of the wire diameter of the traction wire.

5. The adjustable bend sheath of claim 3, wherein the first receiving lumen, the second receiving lumen, and the third receiving lumen are substantially coaxial; the first pull wire lumen, the internal channel, and the second pull wire lumen are substantially coaxial.

6. The adjustable bend sheath of claim 3, further comprising a passage tube at least partially received in said inner through passage, said passage tube for receiving said pull wire.

7. The adjustable bend sheath of claim 6, wherein the passage tube extends from the distal shaft to the proximal shaft, or only from the main body shaft to the proximal shaft, the passage tube remaining suspended within the main body shaft.

8. The sheath tube of claim 7, further comprising a lining tube, wherein the lining tube is inserted into the first accommodating cavity, the second accommodating cavity and the third accommodating cavity, an outer wall of the lining tube is closely attached to an inner wall of the first accommodating cavity and an inner wall of the third accommodating cavity, and a gap is formed between the outer wall of the lining tube and the inner wall of the second accommodating cavity, so that the pull wire is suspended outside the lining tube in the main body tube body.

9. The adjustable sheath of claim 8, wherein the inner liner tube is sleeved with a first positioning ring and a second positioning ring, the first positioning ring is connected to one end of the channel tube, and the second positioning ring is connected to the other end of the channel tube.

10. The adjustable bending sheath tube of claim 8, wherein the main body tube body comprises a first inner layer, a first reinforcing layer and a first outer layer which are sequentially arranged from inside to outside, and the main body tube body is connected with the distal end tube body and/or the proximal end tube body through the first reinforcing layer.

11. The adjustable bending sheath tube according to claim 10, wherein the distal tube body and/or the proximal tube body each comprise a second inner layer, a second reinforcing layer and a second outer layer, which are sequentially arranged from inside to outside, and the second reinforcing layer of the distal tube body and/or the proximal tube body and the first reinforcing layer of the main tube body are of an integral structure.

12. The sheath of any one of claims 1 to 11, further comprising a fixing ring embedded in the distal shaft, wherein the distal end of the pulling wire is connected to the fixing ring.

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