A combined bracket and a processing method thereof

Abstract

The present invention provides a combined stent, which relates to the technical field of medical devices. The combined stent includes a first stent and a second stent connected axially, wherein the first stent is a dense mesh stent, and the second stent is a cutting stent including an open-loop structure. The first stent has a first connecting portion at the proximal end, and the second stent has a second connecting portion at the distal end, and the first connecting portion and the second connecting portion are buckled. The present invention adopts a scheme of arranging a cutting stent with an open-loop structure at the proximal end of the dense mesh stent, thereby reducing the mesh density at the proximal end of the blood flow guiding device, while not affecting the blood flow guiding effect of the dense mesh stent and the supporting effect at the proximal end. When applied to branch arterial blood vessels, the blood flow obstruction effect of the dense mesh stent on the branch blood vessels can be reduced after the dense mesh stent is implanted, thereby solving the problem of insufficient blood supply to the brain caused by the implantation of the dense mesh stent.

Description

Technical Field

[0001] The invention belongs to the technical field of medical devices, and in particular relates to a combined bracket and a processing method thereof. Background Art

[0002] In the treatment of cerebral vascular bleeding diseases, dense mesh stents are generally used to reconstruct blood flow guidance, or auxiliary stents are used to assist coil embolization. The usual surgical strategy is to first establish a pathway, then deliver dense mesh stents or auxiliary stents and coils and other devices to the lesion site, push out the stents or coils, block the diseased blood vessel aneurysm, and complete the operation.

[0003] In order to block the blood flow at the bleeding site, the mesh diameter of the dense mesh stent is relatively small. However, during the treatment process, if there is a vascular bifurcation near the lesion, it is often necessary to insert the proximal end of the dense mesh stent into the main blood vessel for fixation. Figure 1 As shown in the figure, when the blood from the main vessel flows to the other bifurcated vessel, it will be blocked by the dense mesh stent, resulting in a decrease in the blood flow of the other bifurcated vessel. Previous studies have shown that after blood flow guidance devices such as dense mesh stents are placed in branch arteries, they may cause stenosis or even occlusion of the branch arteries, leading to symptoms such as insufficient blood supply to the brain.

[0004] Reducing the braiding density of dense mesh stents is the most direct way to improve branch artery stenosis after implantation. However, this will reduce the blood flow guidance ability of dense mesh stents, thus affecting their therapeutic effect on bleeding diseases, making them difficult to use clinically. It is difficult to reduce the mesh density at the proximal end of dense mesh stents and maintain a higher mesh density at the distal end during the processing of dense mesh stents.

[0005] Therefore, it is necessary to provide an improved technical solution to address the above-mentioned deficiencies in the prior art. Summary of the invention

[0006] The purpose of the present invention is to provide a combined stent that can reduce the influence of a dense mesh stent on the blood flow of bifurcated vessels, so as to solve the problem that the existing dense mesh stent is prone to cause insufficient blood supply to the brain after intervention.

[0007] Another object of the present invention is to provide a method for processing the above-mentioned combined bracket.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] A combined stent comprises a first stent and a second stent that are axially connected, wherein the first stent is a dense mesh stent, and the second stent is a cutting stent comprising an open-loop structure.

[0010] Preferably, a first connecting portion is provided at a proximal end of the first bracket, and a second connecting portion is provided at a distal end of the second bracket, and the first connecting portion and the second connecting portion are buckled.

[0011] Preferably, the first connecting portion is C-shaped.

[0012] Preferably, the distal end of the second connecting portion passes through the first connecting portion and then bends toward the proximal direction.

[0013] Preferably, the distal end of the second stent is an open hole structure.

[0014] Preferably, the proximal end of the second stent is a closed-loop structure.

[0015] Preferably, a plurality of groups of first wave-shaped rings are provided in the middle portion of the second bracket, and the rod length of the first wave-shaped ring is greater than the rod length of the adjacent wave-shaped ring.

[0016] Preferably, the proximal diameter of the second stent is larger than the distal diameter.

[0017] Preferably, the first connection part and the second connection part are welded after being buckled; or, a ring is provided on the outer side of the second connection part.

[0018] Preferably, the center of the bending part of the second connecting portion is axially tangent to the cylindrical surface of the second bracket.

[0019] Preferably, the sleeve ring is a developing spring or a developing ring.

[0020] The present invention also provides a method for processing any of the above-mentioned combined brackets, the method comprising the following steps:

[0021] The second bracket is subjected to heat treatment for shaping, and during the heat treatment and shaping process, the bending part of the second connecting part is twisted until the central axis is tangent to the cylindrical surface of the second bracket.

[0022] Beneficial effects:

[0023] (1) The present invention adopts a scheme of arranging a cutting stent with an open-loop structure at the proximal end of the dense mesh stent, thereby reducing the mesh density at the proximal end of the blood flow guiding device, while not affecting the blood flow guiding effect of the dense mesh stent and the supporting effect at the proximal end. When applied to branch arterial vessels, the blood flow obstruction effect of the dense mesh stent on the branch vessels after implantation can be reduced, thereby avoiding the problem of insufficient cerebral blood supply caused by the implantation of the dense mesh stent;

[0024] (2) Due to its own structure, the traditional dense mesh stent has general support after opening, limited wall adhesion effect, and there is a risk of displacement under blood flow impact after implantation. The second stent of the present invention is a cutting stent, which can provide better support than the dense mesh stent, and has a better wall adhesion effect after opening, which can reduce the risk of displacement of the dense mesh stent after implantation;

[0025] (3) The second stent can adopt a structure with a small distal diameter and a large proximal diameter, which has better adaptability to blood vessels with large diameter changes;

[0026] (4) By providing a ring at the first connecting portion and the second connecting portion, a mechanical engagement effect can be achieved, which is beneficial to the thrust transmission during the pushing process and facilitates the delivery of the braided stent and the combined stent. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. Among them:

[0028] Figure 1 This is a schematic diagram of vascular stenosis and reduced blood flow in branch vessels caused by implantation of existing dense mesh stents.

[0029] Figure 2 An overall schematic diagram of a combined bracket provided in an embodiment of the present invention.

[0030] Figure 3 Schematic diagram of the first bracket in an embodiment of the present invention.

[0031] Figure 4 Schematic diagram of the second bracket in an embodiment of the present invention.

[0032] Figure 5 It is a schematic structural diagram of the second bracket deployed in a plane in an embodiment of the present invention.

[0033] Figure 6 Schematic diagram of a plan view of a second connecting portion in an embodiment of the present invention.

[0034] Figure 7 2 is a three-dimensional schematic diagram of the second connecting portion in an embodiment of the present invention.

[0035] Figure 8 It is a schematic diagram of the first connecting part and the second connecting part being buckled in an embodiment of the present invention.

[0036] Fig. 9 Schematic diagram of the connection between the first connection part and the second connection part in Example 3 of the present invention

[0037] In the figure: 100, first bracket; 101, first connecting portion; 200, second bracket; 201, second connecting portion; 202, developing rod; 203, sleeve ring. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0039] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0040] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more features.

[0042] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the term "connection" should be understood in a broad sense. For example, it can be a fixed connection or a movable connection, a detachable connection or a non-detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be internal connection between two elements, indirect connection, or an interactive relationship between two elements.

[0043] In the description of the present invention, "proximal end" refers to the end away from the operator, and "distal end" refers to the end close to the operator. Generally, the left side in the drawings of the present invention specification is the "distal end" and the right side is the "proximal end".

[0044] The present invention will be described in detail below in conjunction with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0045] The present invention aims at the problem that blood flow guiding devices such as dense mesh stents currently used in branch arteries may obstruct blood flow in branch vessels and easily cause cerebral blood supply insufficiency. The present invention provides a combined stent to reduce the influence of the dense mesh stent on the blood flow in bifurcated vessels.

[0046] Specifically, the present invention provides a combined bracket, such as Figure 2 As shown in ~~5, it includes an axially connected first bracket 100 and a second bracket 200, the first bracket 100 is a dense mesh bracket, which is woven using braided wires of polymer materials or metal materials; the second bracket 200 is a cutting bracket including an open-loop structure, which is made of metal materials through a cutting process (such as laser cutting), the proximal end of the first bracket 100 is a closed structure, and is provided with a first connecting portion 101, the distal end of the second bracket 200 does not have an open hole structure, and is provided with a second connecting portion 201, the first connecting portion 101 and the second connecting portion 201 are buckled to connect the first bracket 100 with the second bracket 200.

[0047] The present invention adopts a scheme of combining a dense mesh stent with a cutting stent, connects the cutting stent to the proximal end of the dense mesh stent, replaces the dense mesh stent to support the vascular wall of the main blood vessel, and utilizes the large mesh of the cutting stent. When applied to embolization treatment at the branch artery, it can reduce the stent's obstruction to the blood flow of the branch blood vessel, making the blood flow into the branch blood vessel smoother, thereby solving the problem of obstruction of the blood flow of the branch blood vessel when the dense mesh stent is supported on the main blood vessel, resulting in insufficient blood supply to the brain. In addition, the cutting stent also has the advantages of good expandability and strong supporting force. After the stent is released, it can fit closely with the vascular wall, and can effectively prevent the dense mesh stent from moving distally under the flushing of blood flow.

[0048] In a preferred embodiment of the present invention, the first connecting portion 101 is C-shaped, which is obtained by stretching the corner of the proximal braided wire of the first stent 100 in the proximal direction. If the first stent 100 is made of metal, the first connecting portion 101 can also be connected to the corner of the proximal braided wire of the first stent 100 by welding; by making the first connecting portion 101 protrude in the proximal direction, the second connecting portion 201 can be prevented from sliding along the braided wire of the first stent 100 to a certain extent. In some embodiments, the first connecting portion 101 can also be set to a closed ring.

[0049] The distal end of the second connection portion 201 passes through the first connection portion 101 and then bends toward the proximal direction, and the pulling force between the two is used to prevent the first bracket 100 from being separated from the second bracket 200.

[0050] In a preferred embodiment of the present invention, the proximal end of the second bracket 200 is a closed-loop structure, and a plurality (for example, 1, 2, 3, 4, 5, etc.) of developing rods 202 are connected to the proximal end of the second bracket 200 to facilitate determining the proximal position of the second bracket 200 by image during the process of pushing the combined bracket.

[0051] In a preferred embodiment of the present invention, a plurality of groups of first wave rings are provided in the middle of the second stent 200, and the rod length of the first wave ring is greater than the rod length of the adjacent wave ring, so that the first wave ring has a stronger supporting force and plays a major supporting role in the blood vessel, while the short-rod wave rings on both sides of the first wave ring have better adaptability to tortuous blood vessels and can play a role similar to a scaffold, so that the second stent 200 can be better opened and adhered to the wall in the tortuous blood vessel.

[0052] Generally, the diameter of the blood vessel at the site where the stent is implanted changes slightly, and the use of an equal-diameter stent can meet the requirements. However, there are also cases where the thickness of the blood vessel at the implantation site changes greatly. At this time, the equal-diameter stent may have a situation where the distal end is already attached to the wall, but the proximal end is fully expanded but still not completely attached to the blood vessel wall, thereby affecting the fixation of the stent. In order to adapt to blood vessels with large thickness changes, in a preferred embodiment of the present invention, the proximal diameter of the second stent 200 is larger than the distal diameter. In blood vessels with large diameter changes, the use of a second stent 200 with a thick proximal end and a thin distal end can better match the change in blood vessel diameter, thereby obtaining better wall adhesion, so as to avoid the situation where the proximal end is poorly attached to the wall or even a gap between the proximal end and the blood vessel wall. Furthermore, the diameter change of the second stent 200 from the proximal end to the distal end can be uniform or uneven.

[0053] When manufacturing the second bracket 200, the shape of the second connecting portion 201 can be directly cut out at its distal end by laser cutting, such as Figure 6 However, at this time, the central axis of the inscribed circle at the bending point of the second connecting portion 201 is parallel to the central axis of the inscribed circle of the first connecting portion 101, and it is difficult to pass the second connecting portion 201 through the first connecting portion 101. Therefore, in a preferred embodiment of the present invention, Figure 7 , 8 As shown, the bending part of the second connecting part 201 is twisted so that the center point of the inscribed circle of the bending part of the second connecting part 201 is axially tangent to the cylindrical surface of the second bracket 200, and is axially perpendicular to the center point of the inscribed circle of the first connecting part 101, so that the second connecting part 201 can be directly passed through the first connecting part 101 by a braiding machine without manual threading.

[0054] In a preferred embodiment of the present invention, the first connection part 101 and the second connection part 201 are welded after being buckled to prevent the first connection part 101 and the second connection part 201 from being separated during the push-pull process; or Fig. 9As shown, a ring 203 is provided on the outer side of the second connecting part 201. The ring 203 can be pre-mounted on the proximal end of the second connecting part 201. After the second connecting part 201 passes through the first connecting part 101, the ring 203 is pushed toward the distal direction so that the head end of the second connecting part 201 is inserted into the inside of the ring 203. The ring 203 is used to prevent the second connecting part 201 from being separated from the first connecting part 101.

[0055] In a preferred embodiment of the present invention, the ring 203 is made of a developing material, such as tungsten alloy, so that it can be developed on the image. More specifically, the ring 203 is a developing ring, and its inner diameter is slightly larger than the size of the second connecting part 201. After the cutting bracket is manufactured, the second connecting part 201 is passed through the ring 203; or, the ring 203 is a developing spring, which is formed by winding a developing wire at the connection after the second connecting part 201 is buckled with the first connecting part 101.

[0056] The present invention also provides a method for processing any of the above-mentioned combined brackets, the method comprising the following steps:

[0057] (1) Weaving the first stent 100 by a weaving machine, and manufacturing the second stent 200 by laser cutting, and pulling out the first connecting portion 101 at the proximal end of the first stent 100, and forming the second connecting portion 201 at the distal end of the second stent 200 by laser cutting;

[0058] (2) The second bracket 200 is heat treated and shaped. During the heat treatment and shaping process, the bending part of the second connecting portion 201 is twisted by 90° so that the center of the inscribed circle of the bending part is axially tangent to the cylindrical surface of the second bracket 200;

[0059] (3) The first connecting portion 101 and the second connecting portion 201 are buckled together and fixed by welding or by a collar 203 to complete the manufacture of the combined bracket.

[0060] The following is a detailed description of a combined bracket and a processing method thereof according to the present invention through specific embodiments.

[0061] Example 1

[0062] This embodiment provides a combined bracket, such as Figures 2 to 5 As shown, it includes a first stent 100 disposed at the distal end and a second stent 200 disposed at the proximal end, wherein the first stent 100 is a dense mesh stent obtained by weaving wires, and the second stent 200 is a cutting stent, as shown in FIG. Figures 3 to 8 As shown, a first connection portion 101 is disposed at a proximal end of the first bracket 100 , and a second connection portion 201 is disposed at a distal end of the second bracket 200 , and the first connection portion 101 and the second connection portion 201 are buckled.

[0063] The proximal end of the second stent 200 is a closed-loop structure composed of two groups of wavy rings with shorter rod lengths. Four developing rods 202 are arranged at the proximal end of the closed-loop structure. The proximal position of the second stent 200 can be confirmed by these developing rods 202 during surgery.

[0064] The distal end of the second bracket 200 is a closed-loop structure composed of two groups of wavy rings with shorter rod lengths. A plurality of second connecting parts 201 are provided at the distal end of the closed-loop structure for connecting to the first bracket 100 .

[0065] The portion between the proximal end and the distal end of the second stent 200 is provided with a plurality of first wave rings, the rod length of the first wave ring being greater than the rod length of the adjacent wave ring, and greater than the rod length of the proximal and distal closed-loop structure portions of the second stent 200. The first wave rings are arranged at intervals on the second stent 200, and adjacent first wave rings are separated by wave rings with shorter rod lengths.

[0066] In this embodiment, the first connecting portion 101 is a C-shaped protrusion formed by further bending the braided wire wave crest at the proximal end of the first stent 100 toward the proximal direction, and the second connecting portion 201 is obtained by bending the rod at the distal end of the second stent 200 toward the proximal direction. The bending part of the second connecting portion 201 is C-shaped, and its diameter is greater than twice the width of the rod constituting the second connecting portion 201, as shown in the figure, to avoid excessive stress concentration at the bending part and cause breakage.

[0067] The second connection part 201 is made of the same material as the second bracket 200. During the processing, after the second connection part 201 is bent, the axial direction of the center of the circle at the bending point is perpendicular to the cylindrical surface of the second bracket 200 and is consistent with the axial direction of the center of the circle of the first connection part 101, which makes it difficult for the head end of the second connection part 201 to pass through the first connection part 101 to form a buckle connection. To solve this problem, in the heat treatment and shaping process of the second bracket 200, the second connection part 201 is bent and then twisted once, so that the axial direction of the center of the circle at the bending point is tangent to the cylindrical surface of the second bracket 200. At this time, the axial direction of the center of the circle at the bending point of the second connection part 201 is perpendicular to the axial direction of the center of the circle of the first connection part 101, so that the threading direction is consistent with the braiding direction of the first bracket 100, so that the threading can be completed using a braiding machine.

[0068] In this embodiment, after the second connection part 201 and the first connection part 101 are buckled together, the slit formed by bending the second connection part 201 is sealed by laser welding to prevent the first connection part 101 from being separated from the second connection part 201 .

[0069] Taking the treatment of branch artery hemangioma as an example, during the operation, the combined stent is pushed to the first stent 100 to cover the lesion site of the hemangioma and then released. Thereafter, the first stent 100 expands and covers the lesion site to block the blood flow to the hemangioma. As the release process proceeds, the second stent 200 also gradually expands and adheres to the wall at the main blood vessel outlet of the branch artery to assist in fixing the first stent 100.

[0070] Example 2

[0071] The diameter of the brain artery varies greatly at the distal end. If a general equal-diameter stent is used, the distal lesion position often exerts a greater pressure on the vessel wall, and the proximal wall is insufficiently adhered. To solve this problem, this embodiment provides a combined stent, which is improved on the basis of embodiment 1. Specifically, the difference from embodiment 1 is that the diameter of the second stent 200 gradually increases toward the proximal direction, so that the second stent 200 has better wall adhesion at the blood vessel with a larger proximal diameter.

[0072] Example 3

[0073] This embodiment provides a combined bracket, which is improved on the basis of embodiment 1. Specifically, Fig. 9 As shown, the difference from Example 1 is that the second connection part 201 is not welded at a part of the connection between the first connection part 101 and the second connection part 201, but a ring 203 is used instead of welding.

[0074] By adopting the above solution, not only can the second connection part 201 be prevented from being separated from the first connection part 101, but the mechanical strength of the ring 203 is also higher, and the thrust is transmitted more directly during pushing, which can avoid desoldering when the welding point is subjected to excessive concentrated force.

[0075] Example 4

[0076] The present embodiment provides a combined bracket, which is improved on the basis of the embodiment 1. Specifically, the difference from the embodiment 1 is that the second connecting part 201 is not welded at a part of the connection between the first connecting part 101 and the second connecting part 201, but a ring 203 is used instead of welding. At the same time, the ring 203 is made of a developing material, such as tungsten alloy, which can show the position of the connection between the first bracket 100 and the second bracket 200 on the image, which helps to improve the accuracy of bracket placement.

[0077] In summary:

[0078] The present invention adopts a scheme of arranging a cutting stent with an open-loop structure at the proximal end of a dense mesh stent, thereby reducing the mesh density at the proximal end of a blood flow guiding device, while not affecting the blood flow guiding effect of the dense mesh stent and the supporting effect of the proximal end. When applied to branch arterial blood vessels, the blood flow obstruction effect of the dense mesh stent on the branch blood vessels after implantation can be reduced, thereby avoiding the problem of insufficient blood supply to the brain after implantation of the dense mesh stent.

[0079] In addition, in order to facilitate processing and assembly of the dense mesh bracket and the cutting bracket, the structure of the connection is specially designed, and a weaving machine can be used to directly thread the wire to complete the assembly connection of the dense mesh bracket and the cutting bracket, avoiding the need for manual threading and reducing the difficulty of processing.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A combined bracket, characterized in that: It comprises a first stent and a second stent connected axially, wherein the first stent is a dense mesh stent, and the second stent is a cutting stent including an open-loop structure; A first connecting portion is provided at the proximal end of the first bracket, and a second connecting portion is provided at the distal end of the second bracket. The first connecting portion and the second connecting portion are buckled and fixed by welding or a collar; The first connecting portion is C-shaped; The distal end of the second connecting portion passes through the first connecting portion and then bends toward the proximal direction; The bending part of the second connecting portion is twisted by 90 degrees, and the center of the inscribed circle at the bending part is axially tangent to the cylindrical surface of the second bracket.

2. A combined bracket according to claim 1, characterized in that: The distal end of the second stent is an open hole structure.

3. A combined bracket according to claim 1 or 2, characterized in that: The proximal end of the second stent is a closed-loop structure.

4. A combined bracket according to claim 1 or 2, characterized in that: A plurality of groups of first wave-shaped rings are arranged in the middle of the second bracket, and the rod length of the first wave-shaped ring is greater than the rod length of the adjacent wave-shaped ring.

5. A combined bracket according to claim 1 or 2, characterized in that: The proximal diameter of the second stent is larger than the distal diameter.

6. The combined bracket according to claim 1, characterized in that: The sleeve ring is a developing spring or a developing ring.

7. A method for processing a combined bracket as claimed in claim 1 or 2, characterized in that: The steps include: (1) Weaving the first stent by a braiding machine, manufacturing the second stent by laser cutting, pulling out a first connecting portion at the proximal end of the first stent, and forming a second connecting portion at the distal end of the second stent by laser cutting; (2) performing heat treatment to shape the second bracket, and during the heat treatment, twisting the bending part of the second connecting part by 90 degrees so that the center of the inscribed circle of the bending part is axially tangent to the cylindrical surface of the second bracket; (3) The first connecting part and the second connecting part are buckled together and fixed by welding or sleeve ring to complete the production of the combined bracket.

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