A bracket

Abstract

The present application discloses a stent, wherein the stent is a self-expandable tubular grid structure, the two ends of the tubular grid structure are open, and the stent includes a plurality of connected first grid units, the first grid unit includes a plurality of side bars, and the cross-sectional area of ​​the side bars gradually increases in the direction from the middle of the side bars to the two ends of the side bars. By setting the side bars of the first grid unit in the direction from the middle to the two ends, the cross-sectional area of ​​the side bars gradually increases, so that the stiffness of the side bars gradually increases in the direction from the middle to the two ends, reducing the strain amount of the end of the side bar and the area near the end, so that the stress and strain distribution of the stent is uniform when deformed, avoiding the concentration of stress and strain in the local area, and avoiding the deformation of the stent that affects the size, thereby improving the resilience of the stent.

Description

Technical Field

[0001] The present application belongs to the technical field of medical devices, and specifically relates to a stent. Background Art

[0002] Interventional methods, such as using microcatheters to deliver stents, dilatation balloons, and embolic coils to reach the designated lesion site to treat vascular diseases, have become the standard approach. This approach is very effective in treating diseases in locations where traditional surgical methods would be extremely risky.

[0003] In the past 30 years, interventional treatment, mainly stent implantation, has developed rapidly and has become an important means of treating cardiovascular and cerebrovascular diseases. Stent implantation is based on percutaneous angioplasty. The stent is delivered to the lesion through a catheter to expand, support and clear the blood vessels. After continuous development, stents are now commonly used to treat vascular stenosis and aneurysms. When used to treat stenosis, its function is to support the narrowed blood vessels, keep the blood vessels unobstructed, and reduce the incidence of restenosis. When used to treat aneurysms, its function is to assist in supporting the embolization coil and / or provide blood flow guidance. The ultimate goal is to reduce blood flow in the aneurysm and gradually heal it. However, the stress and strain distribution of existing stents is uneven. Long-term exposure to large stress and strain will cause deformation, affecting size, and reducing resilience, which seriously affects product performance. Summary of the invention

[0004] The present application provides a stent to solve the technical problem that the existing stent thrombectomy stent is subjected to large stress and strain for a long time, which may cause deformation, affect the size and reduce the resilience.

[0005] In order to solve the above technical problems, a technical solution adopted in the present application is: a stent, which is a self-expandable tubular grid structure, both ends of the tubular grid structure are open, and the stent includes a plurality of connected first grid units, each of which includes a plurality of side rods, and the cross-sectional area of ​​the side rods gradually increases in the direction from the middle of the side rods to the two ends of the side rods.

[0006] According to one embodiment of the present application, the width of the side bar gradually increases in a direction from the middle of the side bar to both ends of the side bar.

[0007] According to one embodiment of the present application, the first grid unit includes two oppositely arranged first side rods and two oppositely arranged second side rods, a plurality of first side rods of the first grid units are connected to form a plurality of first line types spiraling along a first direction, a plurality of second side rods of the first grid units are connected to form a plurality of second line types spiraling along a second direction, the first direction is staggered with the second direction, and the length of the first side rod is greater than the length of the second side rod.

[0008] According to an embodiment of the present application, the maximum width at both ends of the first side bar is smaller than the maximum width at both ends of the second side bar.

[0009] According to an embodiment of the present application, the ratio of the maximum width at both ends of the second side bar to the minimum width in the middle of the second side bar is greater than or equal to 1.1 and less than or equal to 1.75.

[0010] According to an embodiment of the present application, a ratio of the maximum width at both ends of the first side bar to the minimum width in the middle of the first side bar is greater than or equal to 1.05 and less than or equal to 1.5.

[0011] According to one embodiment of the present application, the first side bar and the second side bar are wavy in shape.

[0012] According to an embodiment of the present application, a plurality of second side bars of the first grid units are connected to form four second line types of spirals along a second direction, and the four second line types of spirals are arranged at 90° intervals in the circumferential direction.

[0013] According to one embodiment of the present application, a developing structure is provided on the first grid units located at both ends of the tubular grid structure.

[0014] According to one embodiment of the present application, the stent is formed by cutting and shaping a shape memory alloy tube.

[0015] The beneficial effect of the present application is that by setting the side bars of the first grid unit in the direction from the middle to the two ends, the cross-sectional area of ​​the side bars gradually increases, so that the stiffness of the side bars gradually increases in the direction from the middle to the two ends, reducing the strain at the ends of the side bars and the areas near the ends, so that the stress and strain distribution of the bracket is uniform when deformed, avoiding stress and strain concentration in local areas, and avoiding deformation of the bracket that affects its size, thereby improving the resilience of the bracket. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0017] Figure 1 It is a schematic diagram of the overall structure of a bracket embodiment of the present application;

[0018] Figure 2 It is a schematic diagram of the overall unfolded structure of a stent embodiment of the present application;

[0019] Figure 3 It is a schematic diagram of a partial deployment structure of an embodiment of a stent of the present application;

[0020] Figure 4 It is a schematic diagram of the structure of an embodiment of the stent of the present application when it is bent, and is used to show the change in the distance between the inner and outer nodes;

[0021] Figure 5 is a schematic structural diagram of a stent according to an embodiment of the present application, and is used to show two second line shapes that are spiral along a second direction;

[0022] Figure 6 is a schematic diagram of the structure of an embodiment of the stent of the present application when bent, and is used to show the second line shape of two of the stents spiraling in the second direction;

[0023] Figure 7 It is a schematic diagram of the side bar width structure of the first grid unit of an embodiment of the bracket of the present application. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0025] See also Figures 1 to 3 , Figure 1 It is a schematic diagram of the overall structure of a bracket embodiment of the present application; Figure 2 It is a schematic diagram of the overall unfolded structure of a stent embodiment of the present application; Figure 3 It is a schematic diagram of the partial deployment structure of an embodiment of the stent of the present application.

[0026] An embodiment of the present application provides a bracket 100, such as Figure 1 and Figure 2 As shown, the stent 100 is a self-expandable tubular grid structure, the two ends of the tubular grid structure are open, and the stent 100 includes a plurality of connected first grid units 10. The first grid unit 10 includes a plurality of side bars 11, and the cross-sectional area of ​​the side bars 11 gradually increases in the direction from the middle of the side bars 11 to the two ends of the side bars 11.

[0027] Because the stent 100 needs to be stored in the introduction sheath before use, long-term exposure to large stress and strain will cause deformation that affects its size and reduces its resilience, which seriously affects product performance. In addition, the stress and strain of the side rod 11 of the grid unit are more concentrated at both ends. In the present application, the cross-sectional area of ​​the side rod 11 of the first grid unit 10 gradually increases in the direction from the middle to the two ends, so that the stiffness of the side rod 11 gradually increases in the direction from the middle to the two ends, reducing the strain at the end of the side rod 11 and the area near the end, so that the stress and strain distribution of the stent 100 is uniform when deformed, avoiding stress and strain concentration in local areas, and avoiding deformation of the stent 100 that affects its size, thereby improving the resilience of the stent 100.

[0028] In addition, the stent 100 in the present application is a closed-loop stent, which has appropriate radial force and recyclability. The appropriate radial force can enable the stent to resist the elastic retraction of the blood vessel, support the embolization coil in the aneurysm, and form sufficient friction with the blood vessel to prevent the stent from shifting. Recyclability can be recovered or adjusted and repositioned after the stent is released from the microcatheter, so that the surgical error tolerance rate is increased and the stent 100 can be adjusted to an ideal placement.

[0029] In one embodiment, the width of the side bar 11 gradually increases from the middle of the side bar 11 to the two ends of the side bar 11, so that the stiffness of the side bar 11 gradually increases from the middle to the two ends, reducing the strain at the end of the side bar 11 and the area near the end, so that the stress and strain distribution of the bracket 100 is uniform when deformed. By setting different widths at different positions of the side bar 11, the stress and strain distribution is redistributed, which can effectively reduce the adverse effects of stress and strain concentration in local areas, and at the same time does not affect other properties of the bracket 100, and improves the resilience of the bracket 100. The width change of the side bar 11 can be formed by cutting, which is convenient for processing.

[0030] In other embodiments, the thickness of the side bar 11 gradually increases in the direction from the middle of the side bar 11 to the two ends of the side bar 11, so that the stiffness of the side bar 11 gradually increases in the direction from the middle to the two ends, reducing the strain at the end of the side bar 11 and the area near the end, so that the stress and strain distribution of the bracket 100 is uniform when deformed. By setting different thicknesses at different positions of the side bar 11, the stress and strain distribution can also be redistributed, which can effectively reduce the adverse effects caused by the stress and strain concentration in the local area, and at the same time does not affect other properties of the bracket 100, and improves the resilience of the bracket 100. Of course, in other embodiments, the width and thickness of the side bar 11 can be gradually increased in the direction from the middle of the side bar 11 to the two ends of the side bar 11, so that the cross-sectional area of ​​the side bar 11 is gradually increased, and then the stiffness of the side bar 11 is gradually increased in the direction from the middle to the two ends, so that the stress and strain distribution of the bracket 100 is uniform when deformed, avoiding the stress and strain concentration in the local area.

[0031] The existing stent 100 system is designed with a closed-loop structure because of the need for recyclability. The stent units in the closed-loop structure are restrained by many factors, which results in poor bending flexibility and easier folding. Figure 2 and Figure 3 As shown, the first grid unit 10 includes two first side bars 111 and two second side bars 112 disposed opposite to each other, and the first grid unit 10 is similar to a quadrilateral. A plurality of first grid units 10 are connected by nodes, and the first side bars 111 of the plurality of first grid units 10 are connected to form a plurality of first line types spiraling along a first direction, and the second side bars 112 of the plurality of first grid units 10 are connected to form a plurality of second line types spiraling along a second direction, the first direction and the second direction are staggered, and the length of the first side bars 111 is greater than the length of the second side bars 112.

[0032] Since the first side bars 111 of the multiple first grid units 10 are connected, they can be regarded as multiple first line types spiraling along the first direction, and the second side bars 112 of the multiple first grid units 10 are connected, they can be regarded as multiple second line types spiraling along the second direction. The first line type formed by the first side bar 111 and the second line type formed by the second side bar 112 can be regarded as beams, respectively. In addition, the second side bar 112 is shorter, has greater rigidity, and is easier to maintain its own shape. Therefore, when the stent 100 is bent, the second line type formed by the second side bar 112 plays a dominant role in the shape of the stent 100, so that it basically maintains a spiral shape, similar to the effect of weaving. The first side bar 111 is longer, and acts as a flexible connection similar to a spring. When the stent 100 passes through a curved blood vessel where the length of the inner and outer paths changes, it can be deformed accordingly. Figure 4 As shown, Figure 4It is a schematic diagram of the structure of an embodiment of the stent of the present application when bent, which is used to show the change in the distance between the inner and outer nodes. The marked curve connects the node distances at different positions from the inside to the outside. When bending, the distance between the nodes connecting the two first grid units 10 on the inside can be greatly reduced, and the distance between the nodes connecting the two first grid units 10 on the outside can be greatly increased, which can adapt to the change in the length of the inner and outer paths. Through the above-mentioned structural design, the main shape of the stent 100 can be maintained, and the flexibility can be improved, the bending performance of the stent 100 can be effectively improved, and the length change of the inner and outer sides of the bend can be adapted. Because the stent 100 has good flexibility, the stent can fully fit the inner wall of the blood vessel at the bend to avoid the formation of stenotic thrombi and restenosis in the stent.

[0033] Specifically, Figure 5 and Figure 6 As shown, Figure 5 is a schematic structural diagram of a stent according to an embodiment of the present application, and is used to show two second line shapes that are spiral along a second direction; Figure 6 1 is a schematic diagram of the structure of a stent of the present application when bent, and is used to show two second linear shapes that are spiral along the second direction. The second side bars 112 of the plurality of first grid units 10 are connected to form four second linear shapes that are spiral along the second direction, that is, the main structure of the stent 100 forms four spiral second linear shapes, and the four second linear shapes are arranged at 90° intervals in the circumferential direction. Figure 5 and Figure 6 As shown, when the stent 100 is bent, two of the second line shapes shown in the figure are sometimes on the inside and sometimes on the outside, respectively, so that the change of the inner and outer path lengths will not have a great constraint on the structure.

[0034] Furthermore, if Figure 3 As shown, the first side bar 111 and the second side bar 112 are wavy, and compared with the straight line, the wavy first side bar 111 and the second side bar 112 further improve the resilience and flexibility of the bracket 100. In addition, in a specific embodiment, the second side bar 112 is in an S shape, and the first side bar 111 is connected in two S shapes, so that the first side bar 111 is more likely to deform accordingly when the length of the inner and outer paths changes.

[0035] like Figure 3 As shown, due to the different lengths of the first side bar 111 and the second side bar 112, the stress and strain distribution of the bracket 100 is uneven when deforming, resulting in a large concentration of stress and strain. The second side bar 112 is shorter and plays a role in maintaining the basic shape of the bracket 100. Therefore, the average width of the second side bar 112 needs to be greater than the average width of the first side bar 111 to improve its rigidity, so that it has better support force, and the stress and strain distribution is uniform during deformation to avoid stress and strain concentration in local areas. Specifically, Figure 7 As shown, Figure 7 Schematic diagram of the width structure of the side bar of the first grid unit of the bracket of the present application. The maximum width W2 of the two ends of the first side bar 111 is smaller than the maximum width W1 of the two ends of the second side bar 112, thereby improving the stiffness of the two ends of the second side bar 112, avoiding the stress and strain concentration of the second side bar 112 with higher force at both ends, effectively evenly distributing stress and strain, and improving the overall resilience of the bracket 100.

[0036] Specifically, the minimum width W0 of the middle of the first side bar 111 and the minimum width W0 of the middle of the second side bar 112 may be the same. The minimum width W0 of the middle of the first side bar 111 gradually increases and transitions to the maximum width W2 at both ends, and the ratio of the maximum width W2 at both ends of the first side bar 111 to the minimum width W0 of the middle of the first side bar 111 is greater than or equal to 1.05, and less than or equal to 1.5, such as 1.05, 1.25, 1.5, etc. Within this ratio range, the width of the first side bar 111 is reasonably designed, and the stress and strain distribution can be effectively uniform. The ratio of the maximum width W1 at both ends of the second side bar 112 to the minimum width W0 of the middle of the second side bar 112 is greater than or equal to 1.1, and less than or equal to 1.75, such as 1.1, 1.3, 1.5, 1.75, etc. Within this ratio range, the width of the second side bar 112 is reasonably designed, and the stress and strain distribution can be effectively uniform. By increasing the width of the first side bar 111 and the second side bar 112 of the first grid unit 10 where the force is greater, the rigidity is increased, the strain is reduced, the stress and strain distribution is effectively uniform, and the overall resilience of the bracket 100 is improved.

[0037] In one embodiment, the first grid units 10 at both ends of the tubular grid structure are provided with a developing structure 120. Specifically, the developing structure 120 is located on the first side bar 111 or the second side bar 112. Of course, the developing structure 120 can also be provided at the connection node between the first side bar 111 and the second side bar 112. The developing structure 120 is made of a material having a good developing effect under X-rays, including but not limited to platinum, tantalum, gold and alloys thereof.

[0038] In one embodiment, the stent 100 is cut and shaped from a shape memory alloy tube. The metal stent 100 made of the shape memory alloy tube has sufficient radial support force to ensure good wall adhesion. The shape memory alloy has the property of superelasticity, which can cause the stent 100 to undergo a large deformation after being subjected to an external circumferential constraint force, and the stent 100 can still fully restore its shape after the constraint force is removed. This performance can compress the outer diameter of the stent 100 so that it can fit into a microcatheter that functions as a delivery device. Specifically, the stent 100 is a metal stent made by laser engraving a shape memory alloy tube with a superelastic effect and undergoing a post-forming treatment. Preferably, the alloy material can be a nickel-titanium alloy with superelastic properties.

[0039] In summary, the stent 100 in the present application can simultaneously have suitable radial force, good flexibility and recyclability.

[0040] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A bracket, characterized in that: The stent is a self-expandable tubular grid structure, both ends of the tubular grid structure are open, and the stent includes a plurality of connected first grid units, each of the first grid units includes a plurality of side bars, and the cross-sectional area and width of the side bars gradually increase in the direction from the middle of the side bars to the two ends of the side bars; The first grid unit includes two first side bars arranged opposite to each other and two second side bars arranged opposite to each other, the length of the first side bar is greater than the length of the second side bar, and the widths at both ends of the first side bar are smaller than the widths at both ends of the second side bar; The first side bars of the first grid units are connected to form a plurality of first lines spiraling along a first direction, and the second side bars of the first grid units are connected to form a plurality of second lines spiraling along a second direction, wherein the first direction is staggered with the second direction.

2. The bracket according to claim 1, characterized in that: A ratio of a width at both ends of the second side bar to a width in a middle portion of the second side bar is greater than or equal to 1.1 and less than or equal to 1.

75.

3. The bracket according to claim 1, characterized in that: The ratio of the width at both ends of the first side bar to the width in the middle of the first side bar is greater than or equal to 1.05 and less than or equal to 1.

5.

4. The bracket according to claim 1, characterized in that: The first side bar and the second side bar are wavy in shape.

5. The bracket according to claim 1, characterized in that: The second side bars of a plurality of the first grid units are connected to form four second spiral lines along the second direction, and the four second spiral lines are arranged at 90° intervals in the circumferential direction.

6. The bracket according to any one of claims 1 to 5, characterized in that: The first grid units located at both ends of the tubular grid structure are provided with developing structures.

7. The bracket according to claim 1, characterized in that: The bracket is formed by cutting and shaping a shape memory alloy tube.

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