CN111329634B - Implant - Google Patents

Abstract

The invention discloses an implant, which comprises a tubular main body and a half release device connected to the outer surface of the tubular main body, wherein the half release device comprises a limiting rod and a plurality of binding units movably connected with the limiting rod, each binding unit comprises a binding line and a locking assembly, each binding line comprises a fixing part fixedly connected to the tubular main body, and two binding parts respectively extending from two sides of the fixing part, each locking assembly is respectively connected to two binding parts, and when the limiting rod is sleeved in each locking assembly, the binding line circumferentially constrains the tubular main body. The invention has the beneficial effects that: because the fixed part of constraint line fixed connection is in on the tubular main part, the fixed part does not have circumferential motion in the in-process of releasing the constraint for its regional more steady in the expansion, the circumference counterpoint error in this region of greatly reduced.

Description

Implants

Technical Field

The present invention relates to the technical field of interventional medical devices, and in particular to an implant.

Background technique

In the past decade, aortic stent graft endovascular exclusion has been widely used in thoracic and abdominal aortic aneurysms and arterial dissections. It has a definite effect, less trauma, quick recovery, and fewer complications, and has become a first-line treatment method. During the operation, under the monitoring of X-ray fluoroscopy, the stent graft is delivered to the lesion site through the corresponding delivery system. The stent graft isolates the blood flow from the lesion site and eliminates the influence of blood pressure on the lesion site, so as to achieve the purpose of cure.

In order to solve the problem of positioning the stent graft in the body, development marks are usually made at key positions of the stent, and the development marks are used to position the stent graft in the axial and circumferential directions. However, when the stent graft is compressed in the delivery sheath, it has compression wrinkles in the circumferential direction and is in an elongated state in the axial direction. If the stent graft is positioned by development marks at this time, there will be large circumferential and axial deviations.

Summary of the invention

The technical problem to be solved by the present invention is to provide an implant in view of the above-mentioned defects of the prior art.

The technical solution adopted by the present invention to solve the technical problem is:

An implant is provided, comprising a tubular body and a semi-release device connected to the outer surface of the tubular body, the semi-release device comprising a limit rod and a plurality of restraining units movably connected to the limit rod, the restraining unit comprising a restraining line and a locking assembly, the restraining line comprising a fixing portion fixedly connected to the tubular body, and two restraining portions respectively extending from both sides of the fixing portion, the locking assembly being respectively connected to the two restraining portions, and when the limit rod is sleeved in the locking assembly, the restraining line circumferentially restrains the tubular body.

In summary, an implant implementing the present invention has the following beneficial effects: since the restraining line has a fixing portion fixedly connected to the tubular body, the fixing portion does not move circumferentially during the process of releasing the restraint, so that the area where it is located is more stable during the deployment process, and the circumferential alignment error of the area where the fixing portion is located is greatly reduced. In addition, since the two restraining portions extend from both sides of the fixing portion respectively, when the restraint of the limit rod is released, the two restraining portions move circumferentially in opposite directions respectively, that is, the forces acting on the tubular body by the two restraining portions respectively can be at least partially offset, thereby ensuring that the tubular body is smoothly deployed during the process of releasing the restraint.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

FIG1 is a schematic diagram of a luminal stent provided by one embodiment of the present invention in a semi-released state;

FIG2 is a schematic diagram of the luminal stent shown in FIG1 when it is fully deployed;

FIG3 is a schematic diagram of a first locking buckle of the luminal stent shown in FIG1 as a ring-shaped structure;

FIG4 is a schematic diagram of a first locking buckle of the luminal stent shown in FIG1 being a non-annular structure;

FIG5 is a schematic diagram of the restraining line on the luminal stent shown in FIG1 crossing the trough;

FIG6 is a schematic diagram of a limiting ring buckle on the luminal stent shown in FIG1 ;

FIG7 is a schematic diagram of a case where the restraining line on the luminal stent shown in FIG1 does not cross the trough;

FIG8 is a schematic diagram of a positioning member provided on the restraining line of the luminal stent shown in FIG1 ;

FIG9 is a schematic diagram of the first locking buckle and the limiting ring buckle of the luminal stent shown in FIG1 when they are sleeved together;

FIG10 is a schematic diagram of a luminal stent provided in a second embodiment of the present invention in a semi-released state;

FIG11 is a schematic diagram of the luminal stent shown in FIG10 when it is fully deployed;

12 is a schematic diagram of a luminal stent provided in a semi-released state according to a third embodiment of the present invention;

FIG13 is a schematic diagram of the luminal stent shown in FIG12 when it is fully deployed;

FIG14 is a rear view of the endoluminal stent shown in FIG12;

15 is a schematic diagram of a luminal stent provided in a fourth embodiment of the present invention in a semi-released state;

FIG16 is a schematic diagram of the endoluminal stent shown in FIG15 when it is fully deployed;

FIG17 is a schematic diagram of the tubular body of the endoluminal stent shown in FIG16;

FIG18 is a schematic diagram of the luminal stent shown in FIG16 placed in the tumor cavity;

FIG19 is a schematic diagram showing that four windows on the tapered section of the endoluminal stent shown in FIG16 have the same area;

FIG20 is a schematic diagram showing that the inner branch window area on the tapered section of the luminal stent shown in FIG16 is larger than the outer branch window area;

FIG21 is a schematic diagram of a wave-shaped ring of a tapered section of the luminal stent shown in FIG16;

FIG22 is a schematic diagram of the closed connection between the distal end of the inner branch of the endoluminal stent shown in FIG16 and the tubular body;

FIG23 is a schematic diagram of a support rod provided on the inner branch of the luminal stent shown in FIG16;

FIG24 is a schematic diagram of the support rod shown in FIG23 extending to the distal end of the inner branch;

FIG25 is a schematic diagram of the inclined arrangement of the proximal end surface of the inner branch shown in FIG16;

FIG26 is a schematic diagram of a barb structure provided on the luminal stent shown in FIG16;

FIG27 is a schematic diagram of the distal end wave-shaped ring of the inner branch of the luminal stent shown in FIG16 being located above the proximal end wave-shaped ring of the outer branch;

FIG28 is a schematic diagram of the distal end of the inner branch of the endoluminal stent shown in FIG16 being located above the distal end of the outer branch;

FIG. 29 is a schematic diagram showing that the distal end of the inner branch of the luminal stent shown in FIG. 16 is located above the proximal end of the outer branch.

Detailed ways

In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and/or" used herein includes any and all combinations of one or more related listed items.

In the field of interventional medicine, the end of the implant that is closer to the heart after release is usually defined as the proximal end, and the end that is farther from the heart is defined as the distal end.

The present application provides an implant, which can be contained in a delivery sheath in a compressed state and can automatically return to a predetermined shape after being released from the delivery sheath. The implant can be a luminal stent, a valve, an occluder, a filter, and other products.

Referring to Fig. 1, one embodiment of the present application provides an implant, which is a luminal stent 100, comprising a bare stent 101 and a covering 102 connected to the bare stent 101. The luminal stent 100 is a hollow luminal structure, and the lumen of the luminal stent 100 constitutes a channel for blood flow.

Among them, the bare stent 101 is made of materials with good biocompatibility, such as nickel titanium, stainless steel and other materials. The coating 102 is made of polymer materials with good biocompatibility, such as PTFE, FEP, PET and the like. The bare stent 101 includes multiple circles of waveform rings 1011, each circle of waveform rings 1011 includes multiple crests, multiple troughs and multiple connecting rods respectively connecting adjacent crests and troughs, and multiple circles of waveform rings 1011 are arranged in sequence from the proximal end to the distal end, preferably arranged in parallel and spaced apart. The waveform ring 1011 is a closed cylindrical structure, and the multiple circles of waveform rings 1011 can have the same or similar waveform shape. It can be understood that this embodiment does not limit the specific structure of the waveform ring 1011, and the waveform of the waveform ring 1011 can be set as needed, and the number of waveforms in each circle of waveform ring 1011 and the waveform height can be set as needed.

Please refer to Figures 1 and 2. The luminal stent 100 includes a tubular body 11, and a semi-release device 200 connected to the outer surface of the tubular body 11 to circumferentially constrain the tubular body 11. The semi-release device 200 includes a limiting rod 21, and a plurality of restraining units 20 movably connected to the limiting rod 21. Among them, the restraining unit 20 includes a restraining line 22, a locking assembly 23 and at least one limiting ring 24, the locking assembly 23 is connected to the restraining line 22, the limiting ring 24 is fixed on the tubular body 11, and the restraining line 22 and/or the locking assembly 23 pass from one side of the limiting ring 24 to the other side. When the limiting rod 21 is sleeved in the locking assembly 23, the restraining line 22 constrains the luminal body 10 near it circumferentially. Specifically, the locking assembly 23 includes a first locking buckle 231 connected to the restraining line 22 and a second locking buckle 232 connected to the restraining line 22 and/or the tubular body 11 , and the limiting rod 21 is movably connected in the first locking buckle 231 and the second locking buckle 232 .

The present application sets a semi-release device 200 on the outer surface of the luminal stent 100. When the luminal stent 100 is completely released from the delivery sheath, under the constraint of the semi-release device 200, the luminal stent 100 is in a semi-release state. At this time, the luminal stent 100 does not fit the blood vessel wall. The operator can still adjust the axial and circumferential position of the luminal stent 100. After accurate positioning, the constraint of the semi-release device 200 is released to allow the luminal stent 100 to unfold and adhere to the wall. It can be understood that if the diameter of the circumscribed circle of the cross section of the luminal stent 100 is too large when the luminal stent 100 is in a semi-release state, the stent is easy to adhere to the wall, which is not conducive to axial and circumferential adjustment of the luminal stent; if the diameter of the circumscribed circle of the cross section of the luminal stent 100 is too small when the luminal stent 100 is in a semi-release state, the semi-release effect is not great, and there is still a large circumferential and axial positioning deviation. Therefore, in this embodiment, the ratio of the diameter of the circumscribed circle of the cross section of the luminal stent 100 in the semi-released state to the diameter of the circumscribed circle of the cross section of the luminal stent 100 when it is deployed is 0.6 to 0.8.

In the embodiment shown in FIG. 1 and FIG. 2 , a plurality of restraining units 20 are evenly distributed on the outer surface of the tubular body 11 along the axial direction, and each restraining unit 20 is distributed along the circumferential direction so that the tubular body 11 is evenly restrained. The restraining unit 20 includes a plurality of limiting ring buckles 24 evenly distributed along the circumferential direction, and the restraining line 22 is passed through each limiting ring buckle 24. The first lock buckle 231 and the second lock buckle 232 are both annular structures, and the first lock buckle 231 is arranged at one end of the restraining line 22, and the second lock buckle 232 is arranged at the other end of the restraining line 22. During assembly, the limiting rod 21 is respectively sleeved into the first lock buckle 231 and the second lock buckle 232. After accurate positioning, the limiting rod 21 is pulled out from the first lock buckle 231 and the second lock buckle 232 to release the restraint. It is understandable that the present embodiment does not limit the specific positions of the first lock buckle 231 and the second lock buckle 232 on the binding line 22. In other embodiments, the first lock buckle 231 or the second lock buckle 232 may also be located in other areas outside the end of the binding line 22. It is also understandable that the present embodiment does not limit the specific number of the second lock buckles 232. For example, the second lock buckles 232 may also include two, one of which is connected to the binding line 22 and the other is connected to the tubular body 11.

The present application provides a plurality of limiting ring buckles 24 on the outer surface of the tubular body 11, and allows the binding wire 22 and/or the locking assembly 23 to pass through the limiting ring buckle 24, so that the binding wire 22 can uniformly compress the tubular body 11, thereby improving the accuracy of the overall positioning of the stent. In addition, when the luminal stent 100 is compressed in the delivery sheath or the constraint of the binding wire 22 on the luminal stent 100 is released, the limiting ring buckle 24 can also prevent the binding wire 22 from axial displacement.

It can be understood that in other embodiments, the locking buckle assembly 23 passes from one side of the limiting ring buckle 24 to the other side. For example, in the embodiment shown in Figure 3, the first locking buckle 231 is an annular structure, which is connected to one end of the restraining line 22, and the first locking buckle 231 is hooked on the limiting ring buckle 24.

It can also be understood that the present embodiment does not limit the specific structure of the first lock buckle 231 and the second lock buckle 232, as long as the limiting rod 21 can be movably connected in the first lock buckle 231 and the second lock buckle 232. For example, in the embodiment shown in FIG4, the first lock buckle 231 is not a closed ring structure, and the first lock buckle 231 is hooked on the limiting ring buckle 24, that is, the first lock buckle 231 passes from one side of the limiting ring buckle 24 to the other side and then folds back, and at this time, the binding line 22 and the first lock buckle 231 are an integrated structure.

It can also be understood that if the number of the limiting ring buckles 24 is too small, the distance between two adjacent limiting ring buckles 24 will be too long. When the constraint of the semi-release device 200 is released, it is easy to cause the area between the two limiting ring buckles 24 of the luminal stent 100 to be sunken, so that the stent in this area cannot be deployed and attached to the wall. In addition, as shown in FIG5, if the distance between the two limiting ring buckles 24 is too long, when the luminal stent 100 is in a radially compressed state, the restraining line 22 between the two limiting ring buckles 24 will be axially displaced, and even cross the trough of the wave-shaped ring 101 and hook on the trough, so that the stent cannot be normally deployed.

Please refer to Figures 6 and 7. The straight-line distance between two adjacent limiting ring buckles 24 is e, and the vertical distance between the fixed point of the limiting ring buckle 24 and the trough located below the limiting ring buckle 24 and closest to the limiting ring buckle 24 is f, where e and f satisfy e≤2f, so as to avoid the restraining line 22 crossing the trough of the corrugated ring 101 when the luminal stent 100 is in a radial compression state. In this embodiment, the limiting ring buckles 24 are all arranged on the corrugated ring 1011, which is not only conducive to radial compression of the stent, but also reduces the risk of damage to the coating by the restraining line 22. Preferably, the limiting ring buckle 24 is located in the middle of the connecting rod of the corrugated ring 1011 to make the force on the corrugated ring 101 uniform.

Further, an anti-slip structure is provided between the lock assembly 23 and the limiting ring buckle 24 to prevent the lock assembly 23 from slipping off from the limiting ring buckle 24 after the constraint is released, causing the axial displacement of the binding line 22. In the embodiment shown in FIG8, the anti-slip structure is a positioning member 25 provided at the connection between the binding line 22 and the first lock buckle 231 or/and the second lock buckle 232, and the outer diameter of the positioning member 25 is greater than the inner diameter of the limiting ring buckle 24, so that the positioning member 25 cannot pass through the limiting ring buckle 24. It can be understood that this embodiment does not limit the specific position of the positioning member 25 on the binding line 22. For example, in other embodiments, the positioning member 25 is located between the two limiting ring buckles 24. It can also be understood that in other embodiments, the anti-slip structure may not be provided, and the lock assembly 23 and the limiting ring buckle 24 are prevented from slipping off by other means. For example, in the embodiment shown in FIG9, the first lock buckle 231 is hooked with the limiting ring buckle 24 to prevent the lock assembly 23 from slipping off from the limiting ring buckle 24.

It is understandable that if the size of the limiting ring buckle 24 is too large, the range of axial movement of the restraining line 22 is large, which affects the radial compression effect of the stent. However, if the size of the limiting ring buckle 24 is too small, the friction between the limiting ring buckle 24 and the restraining line 22 will increase, affecting the circumferential relative movement of the two, which is not conducive to the smooth deployment of the stent. Therefore, in this embodiment, the ratio of the area of the limiting ring buckle 24 to the cross-sectional area of the restraining line 22 is 1.1 to 2. It should be noted that when the limiting ring buckle 24 is annular, the "area of the limiting ring buckle 24" refers to the inner area of the ring of the limiting ring buckle; when the limiting ring buckle 24 is a line segment with both ends fixed on the tubular body 11, the "area of the limiting ring buckle 24" refers to the area enclosed by the limiting ring buckle 24 and the tubular body 11.

Please refer to FIG. 2 again, the binding wire 22 further includes at least one fixing portion 221, which can be fixed to the tubular body 11 by suturing or bonding, etc. When the binding wire 22 slips off all the limiting ring buckles 24, the fixing portion 221 can prevent the binding wire 22 from detaching from the stent and entering the downstream blood vessel. In the embodiment shown in FIG. 2, the fixing portion 221 is located at the end of the binding wire 22.

In this embodiment, the binding line 22 can be a flexible line with strong tensile resistance, such as polyester suture. The binding line 22 can be composed of a single flexible line or a plurality of flexible lines. The limiting ring buckle 24, the first lock buckle 231, and the second lock buckle 232 can all be polyester suture coils or nickel-titanium metal rings. The limiting rod 21 can be a metal guide wire with a small surface roughness and good biocompatibility with the human body, such as nickel-titanium wire. In order not to increase the overall outline size of the stent and avoid bending of the limiting rod 21 under force, the wire diameter of the limiting rod 21 is 0.2mm to 0.6mm. Furthermore, in order to reduce the resistance when the limiting rod 21 is withdrawn, the ratio of the area of the first lock buckle 231 or the second lock buckle 232 to the cross-sectional area of the limiting rod 21 is 1.5 to 3. It should be noted that, when the first lock buckle 231 or the second lock buckle 232 is annular, “the area of the first lock buckle 231 or the second lock buckle 232” refers to the inner area of the ring of the first lock buckle 231 or the second lock buckle 232; when the first lock buckle 231 or the second lock buckle 232 is a line segment with both ends fixed on the tubular body 11, then “the area of the first lock buckle 231 or the second lock buckle 232” refers to the area enclosed by the first lock buckle 231 or the second lock buckle 232 and the tubular body 11.

In the embodiments shown in FIG. 1 and FIG. 2 , when the limit rod 21 is sleeved in the locking assembly 23, the binding line 22 constrains the entire circumference of the luminal stent 100. It is understandable that in other embodiments, when the limit rod 21 is sleeved in the locking assembly 23, the binding line 22 can only constrain part of the luminal stent 100 in the circumferential direction. However, if the range of the constraint area where the binding line 22 is circumferentially constrained is too small, the compression degree of the stent in the constraint area in the radial direction will be large. During the deployment of the stent, the stent in the constraint area has not been fully deployed, and the stent in other areas has already been attached to the wall, resulting in a large groove in the constraint area, causing the stent to be poorly attached to the wall as a whole, increasing the risk of internal leakage. Therefore, in this embodiment, when the limit rod 21 is sleeved in the locking assembly 23, the angle of the constraint area where the binding line 22 is circumferentially constrained on the tubular body 11 is 180° to 360° along the circumferential direction.

A person of ordinary skill in the art should be aware that the luminal stent of this embodiment is used as an example only and does not limit the present application. The implant of the present application can be any coated luminal stent with a bare stent, including but not limited to a thoracic aortic stent, an abdominal aortic stent, a thoracoabdominal aortic stent, etc.

Referring to Figures 10 and 11, the second preferred embodiment of the present application provides a luminal stent 100, which is substantially the same as the luminal stent of the first embodiment, and the luminal stent 100 includes a tubular body 11, and a semi-release device 200 connected to the outer surface of the tubular body 11. The difference between the second embodiment and the first embodiment is that the tubular body 11 includes a first area 115 and a second area 116 along the circumferential direction, and the semi-release device 200 is arranged in the second area 116.

When the luminal stent 100 is released from the delivery sheath and is in a semi-released state, the first zone 115 of the luminal stent 100 has been fully expanded, and the operator can accurately position the first zone 115 at this time. In addition, when the constraint of the semi-release device 200 is released, the constrained part of the luminal stent 100 gradually expands, and there is no expansion movement in the first zone 115, which greatly reduces the circumferential alignment error of the first zone 115. Therefore, when components with high positioning requirements, such as branches, branch windows, keels, etc., are provided on the tubular body 11, these components with high positioning requirements can be provided in the first zone 115, and only the second zone 116 of the luminal stent 100 is circumferentially constrained, thereby improving the positioning accuracy. In the embodiments shown in Figures 10 and 11, a branch window 30 is provided in the first zone 115.

It is understandable that if the circumferential constraint area of the second zone 116 is too small, the degree of radial compression of the stent in the constraint area will be relatively large. During the deployment of the stent, the stent in the constraint area has not been fully deployed, but the stent in other areas has already adhered to the wall, resulting in large grooves in the constraint area, causing poor adhesion of the stent as a whole, and increasing the risk of internal leakage. However, if the axial constraint area of the second zone 116 is too large, it is not meaningful to locally constrain the luminal stent 100. Therefore, in this embodiment, when the luminal stent 100 is fully deployed, the circumferential angle covered by the second zone 116 is 180° to 340°.

In order to reduce circumferential and axial positioning deviations and avoid the stent sticking to the wall during positioning adjustment, the ratio of the circumscribed circle diameter of the cross section of the luminal stent 100 in a semi-released state to the circumscribed circle diameter of the cross section of the luminal stent 100 when it is deployed is also 0.6 to 0.8.

In the embodiment shown in FIG. 10 and FIG. 11 , the restraining unit 20 includes a plurality of limiting ring buckles 24 evenly distributed along the circumferential direction, and the restraining line 22 is passed through each limiting ring buckle 24. The first locking buckle 231 and the second locking buckle 232 are both annular structures, the first locking buckle 231 is arranged at one end of the restraining line 22, and the second locking buckle 232 is arranged on the tubular body 11. During assembly, the limiting rod 21 is respectively sleeved into the first locking buckle 231 and the second locking buckle 232, and after accurate positioning, the limiting rod 21 is pulled out from the first locking buckle 231 and the second locking buckle 232 to release the restraint.

Since the specific structure of the semi-release device 200 of the second embodiment is the same as that of the first embodiment, the specific structure of the semi-release device 200 will not be described in detail herein.

Please refer to Figures 12, 13 and 14. The third preferred embodiment of the present application provides a luminal stent 100, which is substantially the same as the luminal stent of the first embodiment. The luminal stent 100 includes a tubular body 11 and a semi-release device 200 connected to the outer surface of the tubular body 11. The semi-release device 200 includes a limiting rod 21 and a plurality of restraining units 20 movably connected to the limiting rod 21. The restraining unit 20 includes a restraining line 22 and a locking assembly 23. The locking assembly 23 includes a first locking buckle 231 connected to the restraining line 22, and a second locking buckle 232 connected to the restraining line 22 or/and the tubular body 11. The limiting rod 21 is movably connected to the first locking buckle 231 and the second locking buckle 232.

The third embodiment is different from the first embodiment in that the binding line 22 includes a fixing portion 221 and two binding portions 222 extending from both sides of the fixing portion 221, the fixing portion 221 can be fixed to the tubular body 11 by suturing or bonding, and the locking assembly 23 is respectively connected to the two binding portions 222. When the limiting rod 21 is sleeved in the locking assembly 23, the binding line 22 circumferentially constrains the tubular body 11 near it.

Since the two binding parts 222 of the binding line 22 extend from both sides of the fixed part 221 respectively, when the constraint of the limit rod 21 is released, the two binding parts 222 move circumferentially in opposite directions respectively, that is, the forces of the two binding parts 222 acting on the tubular body 11 respectively can be at least partially offset, thereby ensuring that the tubular body 11 is smoothly unfolded during the process of releasing the constraint. In addition, since the fixed part 221 is fixedly connected to the tubular body 11, there is no circumferential movement of the fixed part 221 during the process of releasing the constraint, making the area where it is located more stable during the unfolding, greatly reducing the circumferential alignment error of the area. Therefore, when the tubular body 11 is provided with components with high positioning requirements, such as branches, branch windows, keels, etc., these components with high positioning requirements can be set near the fixed part 221, thereby improving the positioning accuracy. In the embodiment shown in FIG. 14 , the tubular body 11 includes a first area 115 and a second area 116 along the circumferential direction, the fixing portion 221 is located in the first area 115, the locking assembly 23 is located in the second area 116, and a branch window 30 is provided in the first area 115. It can be understood that the circumferential angle covered by the first area 115 can be determined according to the specific size of the above-mentioned components with high positioning requirements, as long as it can ensure that the above-mentioned components with high positioning requirements can all be located in the first area 115.

It is understandable that, since the fixing portion 221 does not have circumferential movement during the process of releasing the constraint, the positioning effect of the branch window 30 is best when the line connecting the geometric center of the branch window 30 and the fixing portion 221 is parallel to the longitudinal center axis of the tubular body 11. It is also understandable that, when the lengths of the two restraining portions 222 are equal, the forces acting on the tubular body 11 by the two restraining portions 222 can be completely offset, ensuring that the tubular body 11 is smoothly unfolded during the process of releasing the constraint. It is also understandable that, since the fixing portion 221 is provided on the restraining line 22, when the restraining line 22 slips from all the limiting ring buckles 24, the fixing portion 221 can prevent the restraining line 22 from detaching from the stent and entering the downstream blood vessel.

Furthermore, the binding unit 20 also includes at least one limiting ring buckle 24, the limiting ring buckle 24 is fixed on the tubular body 11, and the binding line 22 and/or the locking assembly 23 pass from one side of the limiting ring buckle 24 to the other side. In the embodiment shown in Figure 11, a plurality of binding units 20 are evenly distributed on the outer surface of the tubular body 11, and each binding unit 20 is distributed along the circumferential direction. The binding unit 20 includes a plurality of limiting ring buckles 24 evenly distributed along the circumferential direction, and the binding line 22 passes through each limiting ring buckle 24. The locking assembly 23 includes a first locking buckle 231 connected to the end of one binding portion 222, and two second locking buckles 232 respectively connected to the end of the other binding portion 222 and the tubular body 11, and the first locking buckle 231 and the second locking buckle 232 are both annular structures. During assembly, the limiting rod 21 is respectively sleeved into the first lock buckle 231 and the two second lock buckles 232. After accurate positioning, the limiting rod 21 is pulled out from the first lock buckle 231 and the second lock buckle 232 to release the constraint. It can be understood that the present embodiment does not limit the specific positions of the first lock buckle 231 and the second lock buckle 232 on the restraining line 22. In other embodiments, the first lock buckle 231 or the second lock buckle 232 can also be located in other areas outside the end of the restraining line 22.

The present application provides a plurality of limiting ring buckles 24 on the outer surface of the tubular body 11, and allows the restraining wire 22 and/or the locking assembly 23 to pass through the limiting ring buckles 24. In addition, when the luminal stent 100 is compressed in the delivery sheath or the restraint of the luminal stent 100 by the restraining wire 22 is released, the limiting ring buckle 24 can also prevent the restraining wire 22 from axial displacement.

Similar to the first embodiment, the locking buckle assembly 23 can also be passed from one side of the limiting ring buckle 24 to the other side. For example, in the embodiment shown in FIG. 3 , the first locking buckle 231 is an annular structure connected to one end of the restraining line 22 , and the first locking buckle 231 is sleeved in the limiting ring buckle 24 .

As in the first embodiment, this embodiment does not limit the specific structure of the first lock buckle 231 and the second lock buckle 232, as long as the limiting rod 21 can be movably connected in the first lock buckle 231 and the second lock buckle 232. For example, in the embodiment shown in FIG4, the first lock buckle 231 is not an annular structure, and the first lock buckle 231 is hooked on the limiting ring buckle 24, that is, the first lock buckle 231 passes from one side of the limiting ring buckle 24 to the other side and then folds back. At this time, the binding line 22 and the first lock buckle 231 are an integrated structure.

Since the structure, quantity, fixed position of the limiting ring 24, the relationship between the limiting ring 24, the binding line 22 and the locking assembly 23, and the relationship between the limiting rod 21 and the locking assembly 23 are the same as those in the first embodiment, they will not be repeated here.

In the embodiments shown in FIG. 12, FIG. 13 and FIG. 14, when the limit rod 21 is sleeved in the lock assembly 23, the binding line 22 constrains the entire circumference of the luminal stent 100. It is understandable that in other embodiments, when the limit rod 21 is sleeved in the lock assembly 23, the binding line 22 can only constrain part of the luminal stent 100 in the circumferential direction. However, if the circumferential constraint area of the binding line 22 is too small, the compression degree of the stent in the constraint area in the radial direction will be large. During the deployment of the stent, the stent in the constraint area has not been fully deployed, and the stent in other areas has already adhered to the wall, resulting in a large groove in the constraint area, resulting in poor overall wall adhesion of the stent, and increasing the risk of internal leakage. Therefore, in this embodiment, when the limit rod 21 is sleeved in the lock assembly 23, the angle of the constraint area where the binding line 22 constrains the tubular body 11 in the circumferential direction is 180° to 360°.

Please refer to Figures 15 and 16. The fourth embodiment of the present application provides a luminal stent 100, which is substantially the same as the luminal stent of the first embodiment. The luminal stent 100 includes a tubular body 11, and a semi-release device 200 connected to the outer surface of the tubular body 11. The difference between the fourth embodiment and the first embodiment is that the luminal stent 100 also includes two inner branches 12 and two outer branches 13 connected to the tubular body 11. Please refer to Figure 17. The tubular body 11, the inner branches 12 and the outer branches 13 are all coated stents with a hollow lumen, and the hollow lumen constitutes a channel for blood flow. The above-mentioned coated stents all include a bare stent 101, and a coating 102 connected to the bare stent 101.

Since the structure of the semi-releasing device 200 of the fourth embodiment is the same as that of the first embodiment, its specific structure will not be described again.

The tubular body 11 includes a first main body section 111, a tapered section 112, and a second main body section 113 connected in sequence. The cross-sectional area of the first main body section 111 is larger than the cross-sectional area of the second main body section 113. The two inner branches 12 and the two outer branches 13 are connected to the tapered section 112. The distal end of the inner branch 12 is fixed to the tapered section 112, the proximal end is located inside the tubular body 11, and extends toward a side away from the second main body section 113; the proximal end of the outer branch 13 is fixed to the tapered section 112, the distal end is located outside the tubular body 11, and extends toward a side away from the first main body section 111.

Please refer to Figures 17 and 18. During the operation, the first main body section 111 is first attached to the healthy blood vessel wall upstream of the tumor cavity, and the tapered section 112 and the second main body section 113 are retained in the tumor cavity. Subsequently, a guide wire (not shown) is passed through the inner branch 12 or the outer branch 13 and introduced into the branch blood vessel near the tumor cavity to establish a track. Then, one end of the extension stent 14 is sleeved into the inner branch 12 or the outer branch 13, and the other end of the extension stent 14 is located in the branch blood vessel, and the blood flow passing through the tubular main body 11 is introduced into the branch blood vessel through the extension stent 14.

The present application connects two inner branches 12 and two outer branches 13 to the tapered section 112. Since the tapered section 112 is closer to the first main section 111 than the second main section 113, there is more operating space for the guide wire after it passes through the distal end of the inner branch 12 or the outer branch 13, which facilitates the accurate introduction of the guide wire into the branch blood vessel. In addition, by arranging two inner branches 12 and two outer branches 13 on the tapered section 112, the distal ends of the inner branches 12 and the outer branches 13 can be located in different planes, so that the extended stent 14 is arranged in a staggered manner in the tumor cavity, avoiding squeezing between the extended stents 14.

Since the tubular body 11 is provided with developing marks (not shown) for positioning the inner branch 12 and the outer branch 13 respectively, if the inner branch 12 and the outer branch 13 are too close to each other, the developing marks of the inner and outer branches will interfere with each other, which is not conducive to the guide wire being selected into the corresponding branch, affecting the surgical operation and prolonging the operation time. In addition, since the X-ray fluoroscopic image during surgery is a planar image, if the inner branch 12 and the outer branch 13 are too far apart, the outer branch 13 will be located on the opposite side of the inner branch 12. Under the monitoring of the planar image, the developing marks of the inner and outer branches will still interfere with each other, affecting the surgical operation. Therefore, it is necessary to reasonably design the position between the inner branch 12 and the outer branch 13 to avoid interference between the developing marks of the four branches, and to avoid the defects of the branches being too close to each other, resulting in squeezing between the extended brackets 14. In the present application, the two inner branches 12 are located between the two outer branches 13, the angle a between adjacent inner branches 12 and outer branches 13 along the circumferential direction is 60° to 80°, and the angle b between the two outer branches 13 along the circumferential direction is 170° to 180°.

Please refer to FIG. 19 . Four windows 110 are provided on the tubular body 11 . Two of them are inner branch windows 110a connected to the inner branch 12 . The other two are outer branch windows 110b connected to the outer branch 13 . The developing marks (not shown) are provided at or near the edges of the four windows 110 . It should be noted that the plane passing through the geometric center of the inner branch window 110a and the longitudinal center axis of the tapered section 112 is defined as the first plane m . The plane passing through the geometric center of the outer branch window 110b and the longitudinal center axis of the tapered section 112 is defined as the second plane n . Here, “the angle a between the inner branch 12 and the adjacent outer branch 13 along the circumferential direction” refers to the angle a between the first plane m and the adjacent second plane n . “The angle b between the two outer branches 13 along the circumferential direction” refers to the angle b between the two second planes n . It can be understood that the specific structure and connection position of the developing structure are not limited in this embodiment, as long as the positioning of the window 110 can be achieved, such as the developing structure is an elastic metal ring connected to the circumferential outer edge of the window 110 and having a developing function.

In the embodiment shown in FIG. 19 , the areas of the four windows 110 are the same. It is understandable that in other embodiments, the areas of the four windows 110 may be different. For example, in the embodiment shown in FIG. 20 , the area of the inner branch window 110a is larger than the area of the outer branch window 110b. When the inner branch 12 and the outer branch 13 of the luminal stent are released, since the distal end of the outer branch 13 is a free end, under the impact of the blood flow, the distal end of the outer branch 13 will tilt upward, and even touch the inner wall of the tumor cavity, irritating the blood vessels. Since the area of the inner branch window 110a is larger than the area of the outer branch window 110b, most of the blood flow can quickly pass through the inner branch 12, thereby reducing the blood flow pressure of the outer branch 13 and preventing the distal end of the outer branch 13 from tilting and touching the inner wall of the tumor cavity.

It is understandable that in order to prevent the distal end of the outer branch 13 from tilting up and touching the inner wall of the tumor cavity, and to prevent the operating space from becoming too small after the guide wire passes through the distal end of the outer branch 13, the middle part of the outer branch 13 can also be fixed to the tubular body 11 in a point connection manner.

Please refer to Fig. 21, a circle of wave-shaped ring 1011 is arranged on the tapered section, which includes a plurality of wave crests 1012, a plurality of wave troughs 1013 and a plurality of connecting rods 1014 respectively connecting adjacent wave crests 1012 and wave troughs 1013. The wave-shaped ring 1011 has a supporting effect on the surrounding structure. If the proximal end of the outer branch 13 is connected above the wave trough 1013, the wave trough 1013 will have an upward supporting force on the proximal end of the outer branch 13. Since the distal end of the outer branch 13 is a free end, the supporting force will cause the distal end of the outer branch 13 to tilt upward and even touch the inner wall of the tumor cavity; if the proximal end of the outer branch 13 is connected below the wave crest 1012, the wave crest 1012 will have a downward supporting force on the lower end of the outer branch 13, so that the longitudinal central axis of the outer branch 13 is roughly parallel to the longitudinal central axis of the tubular body 11, thereby preventing the distal end of the outer branch 13 from tilting outward and touching the inner wall of the tumor cavity. Therefore, in this embodiment, the proximal end of the outer branch 13 is connected below the crest 1012. Similarly, due to the support of the wave-shaped ring 1011, if the distal end of the inner branch 12 is connected below the crest 1012, the crest 1012 will limit the upward bending angle of the extension bracket 14 sleeved in the inner branch 12. When the upward bending angle of the extension bracket 14 is too large, the extension bracket 14 will be bent. Therefore, in this embodiment, the distal end of the inner branch 12 is connected above the trough 1013 to facilitate the connection of the extension bracket 14.

Further, at least one crest 1012 and one trough 1013 are provided between adjacent inner branch windows 110a and outer branch windows 110b, so as to ensure that the proximal end of the outer branch 13 is connected below the crest 1012, and the distal end of the inner branch 12 is connected above the trough 1013. Preferably, only one crest 1012 and one trough 1013 are provided between adjacent inner branch windows 110a and outer branch windows 110b, so as to reduce the overall sheathing volume of the endoluminal stent.

Please refer to Figure 18 again. Since there are many extension brackets 14, in order to avoid interference between the extension brackets 14, the extension brackets 14 on the adjacent inner branches 12 and outer branches 13 are usually bent to one side, and the extension brackets 14 on the other two adjacent inner branches 12 and outer branches 13 are bent to the other side. That is, the extension brackets 14 sleeved on the adjacent inner branches 12 and outer branches 13 are prone to interference, and the angle a of the adjacent inner and outer branches along the circumferential direction needs to be increased. It can be understood that, under the condition that the arrangement of the inner and outer branches meets the above-mentioned angle requirements, if the angle of the adjacent inner and outer branches along the circumferential direction is to be increased, the angle between the two inner branches 12 along the circumferential direction needs to be reduced.

In the embodiment shown in FIG. 21 , a crest 1012 is provided between two inner branch windows 110a. The crest 1012 can not only support the inner branch window 110a to prevent the inner branch distal end from being sunken, but also ensure that the two inner branch windows 110a are both located above the trough 1013. Further, in order to prevent the two inner branch windows 110a from being too far apart, the waveform angle α of the crest 1012 is 0 to 10°. It should be noted that the “waveform angle α” here refers to the angle between the connecting rods 1014 connected on both sides of the crest 1012. When the waveform angle is 0, the connecting rods 1014 on both sides of the crest 1012 are arranged in parallel. If the fillet radius r at the crest 1012 or the trough 1013 is too large, the stent is not easily compressed, which will affect the overall sheathing volume of the stent. However, if the fillet radius r is too small, the crest 1012 or the trough 1013 will cause greater stimulation to the blood vessel. Therefore, the fillet radius r of the wave crest 1012 and/or the wave trough 1013 of the wave-shaped ring 1011 on the tapered section 112 is 0.5 mm to 1.5 mm.

Please refer to Figure 22. The distal end of each inner branch 12 is fixed on the inner branch window 110a, and the proximal end extends toward the side away from the second main body segment 113. In order to prevent the inner branch 12 from swinging under the impact of blood flow, the inner branch 12 can be fixed on the tubular body 11 to facilitate the selection of the guide wire into the corresponding inner branch 12.

Since there is a certain distance between the two inner branch windows 110a, a gap will be formed between the outer walls of the two inner branches 12 and the inner wall of the tubular body 11, and the gap is prone to cause thrombus formation. Therefore, in order to prevent the thrombus from moving along the gap to the downstream blood vessel, the outer walls of the distal ends of the two inner branches 12 are closed and connected to the inner wall of the tubular body 11, that is, there is no gap between the outer walls of the distal ends of the two inner branches 12 and the inner wall of the tubular body 11. Specifically, the distal ends of the two inner branches 12 can be fixed together by suturing, and then the distal ends of the two inner branches 12 are fixed to the inner wall of the tubular body 11. Further, in order to prevent thrombus formation, the entire outer walls of the two inner branches 12 are closed and connected to the tubular body 11.

In the embodiment shown in FIG. 23 , the heights of the two inner branches 12 are different, and the wave-shaped rings 1011 on the two inner branches 12 are staggered to reduce the overall sheathing volume of the first main body section 111. In addition, at least one support rod 1015 is provided on the inner branch 12 to increase the axial support force of the inner branch 12. The two ends of the support rod 1015 can be respectively connected to two adjacent circles of wave-shaped rings 1011, and the support rod 1015 can be parallel to the longitudinal center axis of the inner branch 12, or can be inclined relative to the longitudinal center axis of the inner branch 12. Preferably, the support rod 1015, the longitudinal center axis of the inner branch 12, and the longitudinal center axis of the first main body section 111 are coplanar, and the axial support effect of the support rod 1015 is the best. In the embodiment shown in FIG. 24 , the support rod 1015 extends to the distal end of the inner branch 12, which can avoid the collapse of the coating area at the distal end of the inner branch 12, facilitate the selection of the guide wire into the inner branch 12, and facilitate the connection of the extended stent.

Please refer to Figure 25. In order to facilitate the selection of the guide wire into the inner branch 12, the proximal end face of the inner branch 12 is tilted relative to the longitudinal center axis of the inner branch 12. It can be understood that the smaller the angle β between the proximal end face of the inner branch 12 and its longitudinal center axis, the more conducive it is for the guide wire to be selected into the inner branch 12. However, if the angle β is too small, it will affect the connection strength between the extended stent and the inner branch 12. Therefore, in this embodiment, the angle β between the proximal end face of the inner branch 12 and the longitudinal center axis of the inner branch 12 is 30° to 60°. Preferably, the lowest point of the proximal end face of the inner branch 12 is located in the plane formed by the longitudinal center axis of the inner branch 12 and the longitudinal center axis of the first main body segment 111, which is most conducive to the selection of the guide wire.

Please refer to Fig. 26, the vertical distance j between the highest point of the proximal end surface of the inner branch 12 and the proximal end of the first main body segment 111 is not less than 20 mm. At this time, when the proximal end of the first main body segment 111 needs to be sleeved with other stents (not shown), the distance difference between the highest point of the proximal end surface of the inner branch 12 and the proximal end of the first main body segment 111 can provide sufficient anchoring area for the other sleeved stents to avoid interference between the other sleeved stents and the inner branch 12.

Furthermore, a barb structure 1016 is provided on the outer wall of the first main body section 111 to enhance the anchoring performance of the tubular stent as a whole. When the proximal outer sleeve of the first main body section 111 is connected with other stents, if the barb structure 1016 is too close to the proximal end of the first main body section 111, the barb structure 1016 is easy to puncture the other stents connected to form internal leakage. However, if the barb structure 1016 is too close to the inner branch 12, it will affect the overall flexibility of the luminal stent. Therefore, the barb structure 1016 is fixed on the outer wall of the first main body section 111 and is located between the proximal end of the inner branch 12 and the proximal end of the first main body section 111. In the embodiment shown in Figure 10, the barb structure 1016 is provided on the corrugated ring 1011 of the first main body section 111, and the vertical distance k between the highest point of the proximal end surface of the inner branch 12 and the barb structure 1016 is 5mm to 15mm.

Please refer to FIG. 27 , the proximal end of the outer branch 13 is fixed on the outer branch window, and the other end extends toward a side away from the first main body section 111. Since both the inner and outer branches are arranged on the tapered section 112, in order to reduce the sheathing volume of the tapered section 112, in this embodiment, the distal end waveform ring 1011b of the inner branch 12 is located above the proximal end waveform ring 1011a of the outer branch 13, that is, the vertical distance h between the wave crest of the proximal end waveform ring 1011a of the outer branch 13 and the wave trough of the distal end waveform ring 1011b of the inner branch 12 is greater than or equal to 0. However, when the above h value is too large, the distance between the distal end waveform ring 1011b and the distal end of the inner branch 12 will be too far, or the distance between the proximal end waveform ring 1011a and the proximal end of the outer branch 13 will be too far, which may easily cause the distal end of the inner branch 12 or the proximal end of the outer branch 13 to collapse. Therefore, the above h value is not greater than 15 mm.

In the embodiment shown in FIG. 28 , the distal end of the inner branch 12 is located above the distal end of the outer branch 13, that is, the vertical distance c between the highest point on the distal end surface of the outer branch 13 and the lowest point on the distal end surface of the inner branch 12 is greater than 0, so as to ensure that when the distal end of the inner branch 12 is just released from the delivery sheath, the outer branch 13 is still in the delivery sheath. Since the blood flow pressure on the stent is relatively large during the release of the stent, it is not conducive to accurately positioning the stent. When the distal end of the inner branch 12 is just released from the delivery sheath, and the outer branch 13 is still in the delivery sheath, the blood flow can quickly pass through the inner branch 12, thereby reducing the impact of the blood flow on the stent system, which is not only convenient for positioning the inner branch 12, but also can make the subsequent release process more stable. It can be understood that if the above c value is too small, it is easy to release the inner branch 12 and the outer branch 13 at the same time during the operation, which is not conducive to the positioning of the stent. Furthermore, if the c value is too large, the length of the outer branch 13 is too long, which will result in insufficient operating space for the guide wire after it passes through the distal end of the outer branch 13, and the guide wire cannot be accurately introduced into the branch blood vessel, thus increasing the operation time. Therefore, the c value is not less than 5 mm and not more than 12 mm.

Furthermore, the distal end face of the outer branch 13 is tilted relative to the longitudinal center axis of the outer branch 13. It can be understood that the smaller the angle between the distal end face of the outer branch 13 and its longitudinal center axis, the more operating space the guide wire has after passing through the distal end of the outer branch 13, so as to facilitate the accurate introduction of the guide wire into the branch blood vessel, but if the angle is too small, it will affect the connection strength between the extended stent and the outer branch 13. Therefore, in this embodiment, the angle between the distal end face of the outer branch 13 and the longitudinal center axis of the outer branch 13 is 30° to 60°.

In the embodiment shown in FIG. 29 , the distal end of the inner branch 12 is located above the proximal end of the outer branch 13, that is, the vertical distance d between the highest point on the proximal end face of the outer branch 13 and the lowest point on the distal end face of the inner branch 12 is greater than 0, so as to ensure that when the distal end of the inner branch 12 is just released from the delivery sheath, the outer branch 13 is still in the delivery sheath. Since the blood flow pressure on the stent is relatively large during the release of the stent, it is not conducive to accurately positioning the stent. When the distal end of the inner branch 12 is just released from the delivery sheath, and the outer branch 13 is still in the delivery sheath, the blood flow can quickly pass through the inner branch 12, thereby reducing the impact of the blood flow on the stent system, which is not only convenient for positioning the inner branch 12, but also can make the subsequent release process more stable. However, if the above d value is too large, the length of the outer branch 13 is too long, which will cause the guide wire to pass through the distal end of the outer branch 13. After the guide wire passes through, the operating space of the guide wire is insufficient, and the guide wire cannot be accurately introduced into the branch blood vessel, increasing the operation time. Therefore, the above d value is not greater than 10mm.

The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims (8)

1. An implant, comprising a tubular body and a semi-release device connected to the outer surface of the tubular body, characterized in that the tubular body comprises a first area and a second area along a circumferential direction, the semi-release device comprises a limit rod and a plurality of restraining units movably connected to the limit rod, the restraining unit comprises a restraining line and a locking assembly, the restraining line comprises a fixing portion fixedly connected to the tubular body, and two restraining portions extending from both sides of the fixing portion respectively, the locking assembly is connected to the two restraining portions respectively, and when the limit rod is passed through the locking assembly, the restraining line circumferentially constrains the tubular body; the restraining unit also comprises a limit ring buckle, the limit ring buckle is fixed to the tubular body, the restraining line is passed through the limit ring buckle; the two restraining portions are of equal length; The fixing portion is located in the first area, the locking assembly is located in the second area, components with high positioning requirements are arranged in the first area, and the components with high positioning requirements are arranged near the fixing portion. 2. The implant according to claim 1 is characterized in that the angle of the constraint area where the restraining line circumferentially constrains the tubular body along the circumferential direction is 180°~360°. 3. The implant according to claim 1 is characterized in that the ratio of the diameter of the circumscribed circle of the cross section of the tubular body when it is in a semi-released state to the diameter of the circumscribed circle of the cross section of the tubular body when it is fully expanded is 0.6~0.8. 4. The implant according to claim 1 is characterized in that the locking assembly includes a first locking buckle connected to one of the binding parts, and a second locking buckle connected to the other binding part, and the limiting rod is movably connected in the first locking buckle and the second locking buckle. 5. The implant according to claim 1, characterized in that an anti-slip structure is provided between the locking assembly and the limiting ring buckle. 6. The implant according to claim 1, characterized in that there are multiple limiting ring buckles, and the multiple limiting ring buckles are distributed along the circumferential direction. 7. The implant according to claim 1, characterized in that the tubular body comprises a plurality of wavy rings, and the limiting ring is buckled on the wavy rings. 8. The implant according to claim 7, characterized in that the wave-shaped ring includes a plurality of wave crests, a plurality of wave troughs and a plurality of connecting rods respectively connecting adjacent wave crests and wave troughs, and the limiting ring is buckled in the middle of the connecting rods.