Method for installing X-ray markers in a stent

Abstract

The present invention relates to a method for connecting an X-ray marker (1) to a base (20) of a support (2), comprising the following steps: providing a base (20) of the support (2), wherein the base (20) comprises a through hole (21) for receiving the X-ray marker (1); providing a flexible film (3) and the X-ray marker (1), so that at least a portion (30) of the film (3) is located between the base (20) comprising a receiving portion and the X-ray marker (1); and pressing the X-ray marker (1) into the through hole (21) of the base (20) while inserting the film (3), so that the X-ray marker (1) is plastically deformed and fixed in the through hole (21) together with the film (3) in a press-fit manner, wherein the film (3) prevents contact between the X-ray marker (1) and the base (20).

Description

Technical Field

[0001] The present invention relates to a method for connecting an X-ray marker to a substrate of an implant, in particular a stent. The invention will be described mainly based on the example of an X-ray marker for a stent, but is not limited thereto. The invention is used to connect a marker to any, in particular biodegradable implant, such as a stent, an occluder, a filter, a heart valve prosthesis (in particular a stent-based aortic valve prosthesis) or other vascular support devices. Background Art

[0002] In this method, the X-ray markers are already attached to the stent by means of, for example, gluing or pressing.

[0003] In the case of adhesive bonding, the problem arises that, on the one hand, it is difficult to precisely meter relatively small amounts of adhesive, and on the other hand, the exact positioning of the amount of adhesive presents another challenge. In principle, adhesive bonding also has the problem of having a limited processing duration (pot life). Furthermore, when using solvent-based adhesives, it must be ensured that these adhesives do not adversely affect the implant or stent.

[0004] Furthermore, the problem in the case of extrusion is that X-ray markers made of noble metals (e.g. gold or platinum, etc.) are often used, which in combination with the base body of the stent made of base metals produce contact corrosion. In particular in the case of biodegradable stents, this can lead to an undesirable acceleration of degradation. In addition, the X-ray markers can penetrate through the stent, so direct contact between the X-ray marker and the base body must be prevented. This applies to all joining methods with direct contact (e.g. by screwing, riveting, etc.).

[0005] US Patent 2016 / 0228267 discloses a method of pressing an X-ray marker into a stent, wherein when the stent is coated, the space between the X-ray marker and the stent can be filled with a polymer.

[0006] Starting from this, the object of the present invention is to connect an X-ray marker to an implant, in particular a stent, in a simple and reliable manner, wherein potential contact corrosion is to be avoided right from the outset. In particular, adhesive bonding is omitted in the process. Summary of the invention

[0007] This object is achieved by a method having the features of claim 1. Advantageous embodiments of the method are provided in the respective dependent claims and will be described below.

[0008] According to claim 1, a method for attaching an X-ray marker to a base body of an implant, in particular a stent, is disclosed, comprising the following steps:

[0009] - providing a base body of the implant, the base body comprising a receiving portion, in particular a through hole, for receiving the X-ray marker;

[0010] - providing the flexible film and the X-ray marker such that at least a portion of the film is located between the substrate comprising the receiving portion, in particular the through hole, and the X-ray marker; and

[0011] - While inserting the film, the X-ray marker is pressed into the receiving part of the substrate, in particular the through hole of the substrate, so that the X-ray marker is plastically deformed and fixed in the receiving part, in particular the through hole, together with the film in a press-fit manner, wherein the film prevents contact between the X-ray marker and the substrate.

[0012] The connection between the X-ray marker and the implant matrix thus achieved has sufficient elasticity in the process, thereby being able to compensate for slight deformations of the implant matrix. In addition, the pressing operation can advantageously be configured such that the wall thickness of the matrix does not increase due to the pressed X-ray marker.

[0013] The receptacle is preferably designed as a cavity or particularly preferably as a through-hole.

[0014] The matrix may comprise a plurality of interconnected struts forming a circumferential grid structure. Such a matrix may be provided by cutting individual regions from a tubular blank, for example by laser cutting. According to a particularly preferred embodiment, the matrix is ​​made of a magnesium alloy, in particular a magnesium-zinc-calcium, magnesium-zinc-aluminum or magnesium-aluminum alloy.

[0015] According to one embodiment of the method, it is provided that, while inserting the film, the X-ray marker is pressed into the cavity or the through hole, so that the X-ray marker contacts the film with the circumferential outer side, and the film abuts against the circumferential inner side of the cavity or the through hole, so that the circumferential part of the film is arranged between the X-ray marker and the substrate.

[0016] In the context of this application, a cavity is understood to be any at least one-sided opening in the basic body of an implant.

[0017] According to one embodiment of the method, it is further provided that, after being pressed into the cavity / through hole, the X-ray marker has a surface extending along the opening plane of the cavity / through hole and this surface is covered by a portion of the film which is connected to the circumferential portion of the film pressed into the through hole. In other words, the X-ray marker is thus embedded in the film after being pressed in, wherein only the other surface of the X-ray marker facing away from the surface covered by the film is exposed.

[0018] According to an embodiment of the method, it is further provided that a portion of the film protruding from the cavity / through hole is cut away so that a circumferential portion of the film on one side of the base body preferably ends at or is arranged flush with the surface of the base body.

[0019] According to another embodiment of the method, it is provided that the protruding portion of the film is removed or cut off by a punching operation during the pressing operation. According to an alternative embodiment of the method, it is provided that the protruding portion of the film is removed or cut off, for example by trimming, and then used for the pressing operation.

[0020] According to an alternative embodiment of the method according to the invention, a film is provided which is dimensioned such that after the X-ray marker has been pressed into the substrate, the film on one side of the substrate does not protrude from the cavity / through-hole.

[0021] According to one embodiment of the method, it is further provided that before being pressed into the through hole, the X-ray marker is spherical or cylindrical. According to one embodiment of the method, it is further provided that after having been pressed into the cavity / through hole, due to its plastic deformation, the X-ray marker is half-shell / disc-shaped and its two surfaces facing away from each other are preferably designed to be flush with the adjoining surfaces of the base body.

[0022] Two pressing jaws can be used to press in the X-ray marker, wherein the X-ray marker and the film are arranged together between the pressing jaws and the pressing jaws are moved towards each other for pressing the X-ray marker and the film into the cavity / through-hole, so that at least one X-ray marker is plastically deformed by the pressing jaws engaged on both sides thereof and, in the process, is fixed in the cavity / through-hole in a press-fit manner. According to one embodiment, the movement of the pressing jaws towards each other can be controlled in such a way that the final thickness of the at least one X-ray marker in the extrusion direction corresponds to the wall thickness of the substrate (see above).

[0023] The film used is preferably designed to be elastically or plastically deformable, so that it can absorb the forces that occur when the X-ray marker is pressed in without tearing.

[0024] According to an embodiment of the method, the provided film comprises or is made of one of the following materials: a plastic material, a polymer, a polyurethane, an electrospun plastic, an electrospun polyurethane, PTFE or silicone.

[0025] According to one embodiment of the invention, it is further provided that the X-ray marker is made of a metal material that is more noble than the metal material from which the substrate is made. According to one embodiment, the X-ray marker may be made of one of the following materials, or may include one of the following materials: a radiopaque metal material, gold, a gold alloy, platinum or a platinum alloy.

[0026] According to a further embodiment of the method, it is provided that the film is fused after the at least one X-ray marker has been pressed in, for example in order to round off the cut edges of the film or in order to evenly distribute the material of the film in an annular gap around the at least one X-ray marker.

[0027] According to one embodiment of the invention, it is further provided that the film is fused when the at least one X-ray marker and the film are pressed into the cavity / through hole. For this purpose, for example, the pressing jaws, by which the at least one X-ray marker and the film are pressed into the through hole, can be heated.

[0028] According to a further embodiment of the method, it is provided that one or more X-ray markers and the film are prefabricated.

[0029] According to one embodiment of the method, in this regard, before being pressed in, a flexible film and an X-ray marker are provided, wherein the X-ray marker is arranged on the film together with further X-ray markers and appropriately fixed there. Thereafter, the individual X-ray markers can be pressed in.

[0030] According to one embodiment, in this regard, before being pressed in, a flexible film and an X-ray marker are provided, wherein the film is arranged on a porous plate comprising a plurality of holes, wherein the X-ray marker and a further X-ray marker are arranged on corresponding film portions covering the holes and are fixed there, wherein a bend is imparted to the corresponding film portion due to the holes of the porous plate being arranged thereunder, wherein before the X-ray marker is pressed into the cavity / through-hole of the substrate, the bend of the film including the X-ray marker fixed thereto is arranged in at least one through-hole.

[0031] According to another alternative embodiment of the method, it is provided that before being pressed in, a flexible film and an X-ray marker are provided, wherein the X-ray marker and the further X-ray marker are arranged adjacent to each other and are coated with a plastic material, preferably polyurethane, using an electrospinning method to form a film.

[0032] Electrospinning is understood to be the production of thin plastic or polymer fibers from a plastic or polymer solution in an electric field. For this purpose, a solution can be accelerated between an electrode and a counterelectrode, wherein the solution is processed in a complex process into tiny fibers, which are ultimately deposited on the counterelectrode. In this process, the X-ray markers can serve as counterelectrode, so that these markers can be directly coated with thin film materials using electrospinning.

[0033] According to another alternative embodiment of the method, it is provided that, before being pressed in, a flexible film and an X-ray marker are provided, wherein the X-ray marker and the further X-ray marker are arranged between two layers of film forming the film and are fixed to the film.

[0034] Another aspect of the invention relates to an implant, in particular a stent, comprising a base body and an X-ray marker which is arranged in a receiving portion of the base body, in particular a through hole, and is connected to the base body by the method according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Embodiments and further features and advantages of the present invention will be described below based on the accompanying drawings. In the accompanying drawings:

[0036] Figure 1A A schematic cross-sectional view of a portion of a base of a stent is shown, the base comprising a through hole, a spherical X-ray marker arranged above the through hole, and a film arranged between the marker and the base, the film to be pressed into the through hole together with the marker;

[0037] Figure 1B Shown according to Figure 1A A schematic cross-sectional view of an X-ray marker arranged together with a portion of the film in a through hole of a substrate;

[0038] Figure 2 A schematic cross-sectional view of an X-ray marker, a film and a substrate is shown, with two pressing jaws moving toward each other for pressing the X-ray marker and the film together into the through hole;

[0039] Figure 3-4 Shown according to Figure 2 The X-ray markers are deformed by the plasticity of the jaws;

[0040] Figure 5 An X-ray marker is shown pressed into a through hole of a substrate, after which a portion of the film protrudes from the through hole;

[0041] Figure 6 shows a schematic cross-sectional view of an X-ray marker, a film and a substrate after the X-ray marker has been pressed into a through hole of the substrate, the portion of the film protruding from the through hole having been removed;

[0042] Fig. 7A shows an SEM image of an indented X-ray marker made of gold in a film made of electrospun polyurethane;

[0043] Figure 7B shows an SEM image of an indented X-ray marker in molten polyurethane viewed from outside the matrix;

[0044] Figure 7C shows an SEM image of an indented X-ray marker in molten polyurethane viewed from inside the matrix;

[0045] Figures 8A-8CA schematic cross-sectional view showing pre-installation of X-ray markers on a thin film on a porous plate; and

[0046] Figures 9A-9B Shown according to Figures 8A-8C Schematic diagram of the X-ray markers inserted into the through-holes of the substrate. DETAILED DESCRIPTION

[0047] Combination Figures 2 to 6 , Figure 1A and 1B An embodiment of a method for connecting an X-ray marker 1 to a base 20 of a bracket 2 according to the present invention is shown, wherein a base 20 of a bracket 2 is provided, wherein the base 20 includes a through hole 21 for receiving the X-ray marker 1, and wherein a flexible film and an X-ray marker 1 are provided, so that at least a portion 30 of the film 3 is located between the base 20 including the through hole 21 and the X-ray marker 1, and wherein the X-ray marker 1 is eventually pressed into the through hole 21 of the base 20 while inserting the film 3, so that the X-ray marker 1 is plastically deformed and fixed in the through hole 21 together with the film 3 in a press-fit manner, wherein the film 3 prevents contact between the X-ray marker 1 and the base 20, thereby preventing contact corrosion.

[0048] The present invention thus describes an alternative mounting option for an X-ray marker 1 in a support 2. Traditionally, these are bonded using adhesive dosing. At the same time, the present invention allows a plastic or polymer connection to be established between the marker 1 and the substrate 20 without dosing adhesive.

[0049] The film 3 used is therefore preferably elastically deformable and designed to absorb the forces generated when the marker 1 is pressed in without tearing. For example, electrospun polyurethane is a film material with these properties. In principle, all electrospinnable plastic materials can be used, or single-layer or multi-layer PTFE or silicone films.

[0050] according to Figure 1A , such a film 3 is placed on a substrate 20 of a support 2. The substrate 20, in particular the prefabricated one or more through holes 21, also called marker holes or eyelets, are aligned in such a way that the marker 1 can be positioned in a blind manner from above, which means that the relevant through hole 21 does not need to be visible through the film 3. Films made of electrospun polyurethane are usually not very transparent. As an alternative, for example, a light source can be placed below the through hole 21. The position of the specific through hole 21 then becomes visible from the corresponding shadow projected. In addition, a counter plunger can be pushed through the specific through hole and then guide the marker 1 during the extrusion operation. Figure 1B It shows that Figures 2 to 4 The X-ray marker 1 and the film 3 are shown arranged in the through hole 21 before the pressing operation.

[0051] Thereafter, the X-ray marker 1, which initially preferably has a spherical shape and can be made, for example, of gold (or another highly radiopaque and soft metal, such as platinum), is pressed into the through hole 21 together with the film 3 by means of the pressure jaws 4. Control is performed using the displacement-controlled movement of the pressure jaws to ensure that the final thickness D of the marker disk 1 corresponds to the wall thickness W of the base body 20 of the support 2. In this way, it can be ensured that the base body is not damaged by the pressing movement and that one or more X-ray markers 1 do not protrude beyond the edge of the base body.

[0052] The film 3 may be of suitable dimensions so that no protruding film portion 33 is present after the pressing operation. Otherwise, the protruding remaining portion 33 of the film 3 is removed. This can be achieved by a punching action during the pressing or after the pressing operation, for example by cutting off the protruding portion 33 of the film 3 (see Figure 5 and 6 ).

[0053] according to Figure 6 While inserting the film 3, the X-ray marker is finally preferably pressed into the through hole 21, so that the X-ray marker 1 contacts the film 3 with the circumferential outer side 1a, and the film 3 abuts against the circumferential inner side 21a of the through hole 21, so that the circumferential portion 31 of the film is arranged between the X-ray marker 1 and the substrate 20, or fills the corresponding annular gap between the marker 1 and the substrate 20.

[0054] according to Figure 6 It is further provided that, after having been pressed into the through hole 21, the X-ray marker 1 has a surface 1b extending along the opening plane of the through hole 21 and the surface 1b is covered by a portion 32 of the film 3 which is connected to the circumferential portion 31 of the film 3 pressed into the through hole 21.

[0055] Furthermore, the pressed film 3 can also be subsequently fused. This can be done, for example, to round the cut edges of the film 3 or to evenly distribute the film material (e.g. polyurethane) in the annular gap. The fusion can be incorporated into the pressing movement, for example by using heatable pressing jaws 4.

[0056] For example, flat-nosed pliers can be used as pressing jaws, with a mechanically limited pressing movement so that further pressing beyond the stent wall thickness is not possible.

[0057] The squeezing motion can also be incorporated into an existing crimping process step. Within the scope of the present application, crimping is understood to mean a process step in which the stent is arranged around an expansion device, such as an expandable balloon of a balloon catheter, and the diameter of the stent is reduced to a diameter for insertion into a substrate. The stent is pressed onto the balloon.

[0058] exist Fig. 8A In an alternative embodiment shown by way of example in FIG. 9 , for example, before the actual mounting step, or before the step of pressing the marker 1 into the associated through-hole 21 of the substrate 20 , an assembly is produced in which the marker 1 is pre-positioned on the film 3 , specifically fixed there.

[0059] For example, a plurality of X-ray markers 1 are pre-mounted on a film 3 on a porous plate (e.g. in the form of a porous metal plate), for example in the form of film strips 3 (see Fig. 8A ), so that the corresponding X-ray marker 1 is arranged on the film section 34 covering a hole 50 of the perforated plate 5 and is pressed into it, thereby producing in each case a curved section 35 of the film 3 which accommodates the marker 1 (see Figure 8B and 8C ).

[0060] according to Fig. 9A and 9B , these bends 35 can then be positioned particularly easily together with the corresponding X-ray markers 1 arranged therein in the associated through-holes 21 of the base body 20 . Figures 2 to 6 (see above) Perform an extrusion operation.

[0061] Furthermore, such an assembly comprising the marker 1 and the film 3 can be produced by directly coating a plurality of X-ray markers 1 with a suitable plastic material / polymer (e.g. polyurethane) by means of electrospinning. As an alternative thereto, there is the option of covering a plurality of X-ray markers 1 on both sides with a film layer (e.g. polyurethane), so that the marker 1 is wrapped in a film 3 consisting of at least two film layers.

[0062] Figures 7A to 7C An SEM image of an X-ray marker pressed into the stent shown using the present invention is shown.

[0063] An advantage of the invention is that the dosing of adhesive (and the attendant disadvantages, see above) can be completely omitted. Cost-effective X-ray markers in their original state (spherical) can be used, since these do not need to have narrow tolerances. The mounting step can also be incorporated into the crimping process.

Claims

1. A method for attaching an X-ray marker (1) to a base (20) of an implant, comprising the following steps: - providing a substrate (20), said substrate (20) comprising a receiving portion for receiving the X-ray marker (1); - providing the flexible film (3) and the X-ray marker (1) such that at least a portion (30) of the film (3) is located between the substrate (20) comprising the receiving portion and the X-ray marker (1); as well as - While inserting the film (3), the X-ray marker (1) is pressed into the receiving part of the substrate (20), so that the X-ray marker (1) is plastically deformed and fixed in the receiving part together with the film (3) in a press-fit manner, and the film (3) prevents contact between the X-ray marker (1) and the substrate (20).

2. The method according to claim 1, wherein: The implant is a stent (2).

3. The method according to claim 1, wherein: The receiving portion is designed as a cavity or a through hole (21).

4. The method according to claim 3, wherein: While inserting the film (3), the X-ray marker (1) is pressed into the cavity or through hole (21), so that the X-ray marker (1) contacts the film (3) with its circumferential outer side (1a), and the film (3) abuts against the circumferential inner side (21a) of the cavity or through hole (21), so that the circumferential portion (31) of the film is arranged between the X-ray marker (1) and the substrate (20).

5. The method according to claim 4, wherein: After having been pressed into the cavity or through hole (21), the X-ray marker (1) has a surface (1b) extending along the opening plane of the cavity or through hole (21), and the surface (1b) is covered by a portion (32) of the film (3), which is connected to the circumferential portion (31) of the film (3) pressed into the cavity or through hole (21).

6. The method according to claim 3, wherein: The portion (33) of the film (3) protruding from the cavity or through hole (21) is removed so that the circumferential portion (31) of the film (3) ends flush with the surface (20a) of the substrate (20) on one side of the substrate (20).

7. The method according to any one of claims 1 to 4, wherein: The film (3) is dimensioned so that after the pressing operation, the film (3) on one side of the base body (20) does not protrude from the cavity or through hole (21) of the base body (20).

8. The method according to claim 4, wherein: The X-ray marker (1) is spherical or cylindrical before being pressed into the through hole (21), and / or after being pressed into the cavity or through hole (21), the X-ray marker (1) is half-shell or disc-shaped due to its plastic deformation.

9. The method according to claim 4, wherein: The X-ray marker (1) is pressed into the cavity or through-hole (21) together with the film (3) by two pressing claws (4); the X-ray marker (1) is arranged together with the film (3) between the pressing claws (4), and the pressing claws (4) are moved toward each other to press the X-ray marker (1) and the film (3) into the cavity / through-hole (21), so that at least one X-ray marker (1) is plastically deformed by the pressing claws (4) engaged on both sides, and in the process, the at least one X-ray marker (1) is fixed in the cavity / through-hole (21) in a press-fit manner.

10. The method according to claim 9, wherein: The movement of the pressure jaws (4) towards each other is controlled so that the final thickness (D) of the at least one X-ray marker (1) corresponds to the wall thickness (W) of the base body (20).

11. The method according to claim 1, wherein: The film (3) comprises a plastic material or is made of a plastic material.

12. The method according to claim 1, wherein: The film (3) comprises a polymer or is made of a polymer.

13. The method according to claim 1, wherein: The film (3) comprises polyurethane or is made of polyurethane.

14. The method according to claim 1, wherein: The film (3) comprises or is made of electrospun plastic.

15. The method according to claim 1, wherein: The film (3) comprises or is made of electrospun polyurethane.

16. The method according to claim 1, wherein: The film (3) comprises or is made of one of the following materials: PTFE or silicone.

17. The method according to claim 1, wherein: The X-ray marker (1) is made of a metal material that is more noble than the metal material of which the base body (20) is made.

18. The method according to claim 1, wherein: The X-ray marker (1) is made of a radiopaque metal material, or includes a radiopaque metal material.

19. The method according to claim 1, wherein: The X-ray marker (1) is made of one of the following materials, or includes one of the following materials: gold, gold alloy, platinum or platinum alloy.

20. The method according to claim 3, wherein: The film (3) is fused after the at least one X-ray marker (1) has been pressed in.

21. The method according to claim 20, wherein: When the at least one X-ray marker (1) and the film (3) are pressed into the cavity or through hole (21), the film (3) is fused.

22. The method according to claim 3, wherein the flexible film (3) and the X-ray marker (1) are provided as: - the film (3) is arranged on a porous plate (5) comprising a plurality of holes (50), the X-ray marker (1) and the further X-ray marker are each arranged on a film portion (34) covering the holes (50) and fixed there, since the holes (50) of the porous plate (5) are arranged thereunder, a bend (35) is given to the respective film portion (34), and before the X-ray marker (1) is pressed into a cavity or through hole (21) of a substrate (20), the bend (35) of the film portion (34) including the X-ray marker (1) fixed thereon is arranged in the cavity or through hole (21), or is provided as - the X-ray marker (1) and the further X-ray marker (1) are arranged adjacent to each other and coated with a plastic material using an electrospinning method to form a film, or is provided as The X-ray marker (1) and the further X-ray marker (1) are arranged between two films (3) forming the film (3).

23. The method according to claim 22, wherein: The plastic material is polyurethane.

24. An implant comprising a base body (20) and an X-ray marker (1), the X-ray marker (1) being arranged in a receiving portion of the base body (20) and being connected to the base body (20) by a method according to any of the preceding claims.

25. Implant according to claim 24, which is a stent (2).

26. Implant according to claim 24, the receiving portion being a through hole (21).

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