Implant and covering for an implant

Abstract

The present invention relates to an implant comprising a body and a tubular cover, which may be made of a material that is only slightly stretchable. In this case, the cover (10, 20, 30, 40) is placed in a circumferential direction (U) of the tube in a first zigzag fold (11, 21, 31, 41) and at least one second zigzag fold (12, 22, 23, 24, 32, 42), which are arranged adjacent to one another in the circumferential direction (U) and are configured such that in each case, the first zigzag fold (11, 21, 31, 41) is folded in the circumferential direction (U) of the tube, and the second zigzag fold (12, 22, 23, 24, 32, 42) is folded in the circumferential direction (U) of the tube. Two adjacent zig-zag folds of the first zig-zag fold (11, 21, 31, 41) and the at least one second zig-zag fold (12, 22, 23, 24, 32, 42) are folded in mirror symmetry with respect to an imaginary mirror plane (17, 27), which extends between the respective two adjacent zig-zag folds and transversely with respect to the circumferential direction (U) in the longitudinal direction of the tube. The invention also relates to a corresponding cover and to a method for producing a cover and an implant.

Description

Technical Field

[0001] The present invention relates to an implant having a body that forms a circumferential and perforated lateral surface, wherein the body can assume a compressed state and a dilated state. The implant further includes a covering on the lateral surface, which is also referred to as a cap or skirt. The present invention also relates to a tubular covering for such an implant, as well as a method for manufacturing a cap and a method for manufacturing such an implant. Background Art

[0002] Implants having a body (main body, support body, frame) and a covering (cap, skirt) are known, which body forms a circumferential and perforated lateral surface. For example, such implants are used in the form of endovascular prostheses (endoprostheses, stents, stent-grafts), which can be used to treat stenosis (vasoconstriction). They typically have a hollow cylindrical or tubular body that is open at two longitudinal ends of the tube. Such a body is usually mainly formed by a plurality of interconnected struts, which can be at least partially zigzag or meandering. The implant is placed in the blood vessel to be treated and is used to support the blood vessel. In this case, the covering arranged on the body can prevent restenosis, since the material of the covering prevents tissue growth into the interior of the stent. In addition, when the blood vessel to be treated has a wall injury (dissection), such a stent (covered stent) is used. If the stent is immediately used as an emergency treatment for an anatomically relevant occlusion or vascular rupture, the procedure is also referred to as emergency stenting. Such implants are also used in bypass surgery. Implants such as prosthetic heart valves also have a stent-like body that is at least partially provided with a covering (skirt) in order to prevent regurgitation. The present invention can also be used for stents and similar implants in the neurovascular field.

[0003] The body of the implant has two states, namely a compressed state and a dilated state. In particular, the body has a compressed state or a dilated state, and the body is configured to be able to transition from the compressed state to the dilated state and vice versa. In the compressed state with a smaller outer diameter of the body, the implant can be delivered to the treatment site through the vascular system, for example, by means of a catheter. There, the implant is expanded, for example, by means of a balloon of the catheter, and is transferred to the dilated state, in which the implant has a larger outer diameter. A transition to the dilated state can also occur due to a transformation of a shape memory alloy caused by a temperature change. Then, the implant with the dilated body remains at the corresponding treatment site in the patient's body and continues to exert its desired effect there.

[0004] The transition from the compressed state to the dilated state (or vice versa) involves a rather large increase in the diameter of the body. When using a covering placed on the lateral surface of the body, the covering must allow this change in diameter such that the covering is not damaged or the compression or dilation of the body is not hindered. This places special requirements on the arrangement and configuration of the covering.

[0005] It is known to use electrostatic force to spin polyurethane fibers onto the lateral surface of the expansion stent, where they form a thin and highly elastic film. On the one hand, this produces an implant with a very small outer diameter under compression, and on the other hand, this implant can be easily compressed (e.g., by means of curling) because the material of the spun covering compresses and yields to the remaining gap between the pillars of the main body when the diameter is reduced. This spun covering has high production costs and is also limited to materials that allow spinning and stand upright when compressed. Alternatively, a sheath with an overlapping area formed under compression can be provided. In this modification, the covering is subjected to uneven stress during expansion, i.e., particularly in the area of ​​the overlapping portion. In addition, due to their folding structure, known sheaths show that they transmit torque to the expanded implant along the longitudinal axis of the implant during deployment. Such torque may cause the torsion of the implant and make it difficult or impossible for the implant to expand. Therefore, especially for non-expandable or low-expandable covering materials or non-upright materials, an implant solution that allows easy and uniform compression or expansion along the entire body is sought. Summary of the invention

[0006] The above-mentioned problem is solved by a tubular covering having the features of claim 1 , an implant having the features of claim 9 , a method for producing a covering having the features of claim 11 and a method for producing an implant having the features of claim 13 .

[0007] In particular, the above-mentioned problem is solved by a tubular covering for an implant, wherein the covering is laid along the circumferential direction of the tube with a first zigzag fold and at least one second zigzag fold, the first zigzag fold and the at least one second zigzag fold being arranged adjacent to each other in the circumferential direction and being configured so that in each case, two adjacent zigzag folds of the first zigzag fold and the at least one second zigzag fold in the circumferential direction are folded mirror-symmetrically with respect to an imaginary mirror plane, which extends transversely with respect to the circumferential direction between the corresponding two adjacent zigzag folds and in the longitudinal direction of the tube.

[0008] In an exemplary embodiment, the tubular covering has an even number of zigzag folds adjacent to one another in the circumferential direction, for example the covering has a first zigzag fold and a second zigzag fold or a first zigzag fold, a second zigzag fold, a third zigzag fold and a fourth zigzag fold or a number of 2×N zigzag folds, where N>=3, wherein all zigzag folds are arranged adjacent to one another in the circumferential direction and wherein in each case two zigzag folds that are adjacent in the circumferential direction are in each case folded mirror-symmetrically with respect to an imaginary mirror plane arranged between the corresponding two zigzag folds.

[0009] The covering according to the invention is made of a covering element which is shaped in tubular form and whose material has low plasticity and / or elastic deformability, but can be bent / folded. In an exemplary embodiment, the length of the tube in the longitudinal direction is chosen such that it corresponds to the length of the covering in the deployed state of the implant or body.

[0010] Zigzag folding, Z-folding or leporello folding are terms used to describe a folding where layers of a sheet-like element or, as in the present case, layers of a tubular element are formed by two folds in opposite directions to form three layers arranged one above the other, which, when observed in cross-section, form a shape comparable to the letter Z (see Figure 11 ), where, when applied to the covering, the central inclined plane of the "Z" tends to be parallel to the horizontal part of the "Z". In other words, the element is first folded in a first direction such that the material is then circumferentially again, and then folded in a second direction opposite to the circumferential direction of the first direction (i.e., zigzag folding). The result of a single zigzag fold is three circumferentially extending superimposed layers of the material of the covering and two folding edges oriented in opposite circumferential directions. In cross-section, the zigzag fold is shown in Figure 6 and described below. The zigzag fold is longitudinally folded along the entire length of the covering tube such that the material of the covering tube is three-ply in the region of a single zigzag fold along the entire length of the tube.

[0011] According to the invention, the covering has a first zigzag fold and at least one second zigzag fold, i.e., at least two zigzag folds. These folds are arranged side by side along the circumferential direction. This means that each zigzag fold is formed in a separate part of the covering along the circumferential direction such that in each case only three layers of the covering material are superimposed. Furthermore, two adjacent zigzag folds are arranged such that they are mirror-symmetrically folded with respect to a hypothetical mirror plane which lies between the respective two adjacent zigzag folds and extends transversely to the circumferential direction in the longitudinal direction of the tube. This means that, with respect to the radial direction, the folding edges of adjacent zigzag folds lying in the same plane point in opposite directions. The opposite folding edges of adjacent zigzag folds form an opening which facilitates the deployment of the covering during the transition to the expanded state. The folding edges of two adjacent zigzag folds extend in opposite directions, where the lower, middle and upper layers of the adjacent zigzag folds are each substantially in the same plane with respect to the radial direction. It should be noted here that the arrangement of the covering material of adjacent zigzag folds is not completely mirror-symmetric with respect to the virtual mirror plane, but can be described as similar (length of the fold, structure of the fold, etc.). The mirror symmetry of the adjacent zigzag folds defined above is understood with respect to the folding (i.e., flipping) of the covering material.

[0012] The covering folded as shown above is assembled with the compressed body before or after folding to complete the implant, i.e., the compressed body is placed in the internal free space created by folding and applying the fold in the circumferential direction of the covering. This results in an easily expandable implant with a relatively small outer diameter in the compressed state, where the covering can have low ductility. For example, a pericardial covering with a low thrombogenic tendency can be used. Due to the symmetric arrangement of the folds or the symmetric folding technique of the zigzag folding form, the pulling force applied when unfolding the covering at the treatment site during the expansion of the implant or the body is distributed over the zigzag folds arranged adjacent to each other, such that the pulling force is evenly distributed over the entire circumference of the implant or the covering. Thus, peak pulling forces are avoided. Therefore, a smaller force is required during expansion, which leads to better performability of the expansion. In particular, when using four or six zigzag folds along the circumference, the distribution of the force is uniform over the entire circumference of the covering.

[0013] In one exemplary embodiment, as described above, the first zigzag fold and at least one second zigzag fold are placed such that the covering forms an internal, substantially cylindrical free space. In this way, the folds of the covering are closely adjacent to each other along the circumferential direction and facilitate the insertion of the compressed body of the implant into the free space. This also prevents damage to the lid when the body is inserted into the free space.

[0014] In one exemplary embodiment, the covering has a connecting portion, where a first layer of the covering material and a second layer of the covering material are stacked and attached to each other along the longitudinal direction of the covering. Alternatively, the covering material can be manufactured as a tube and thus does not have a connecting portion, for example, in the corresponding forming process for plastic materials or by means of weaving, spinning or knitting processes. If the covering is made of a sheet-like or film-like material, the tubular covering element is made of this material, for example, such that two end portions having the length of the desired covering element are placed one on top of the other and joined or fastened to each other. The portions where the ends are located on top of each other are referred to as the connecting portion. The connecting portion extends along the entire length of the covering element here. The end portions located on top of each other can be fastened by means of one or more seams, adhesive joints or by means of seamless joining techniques with chemical crosslinking, which are described, for example, in WO 2022 / 090417A1. This enables simple manufacture of the covering element.

[0015] The covering material can be single-layered or can be multi-layered. The covering material can include or can consist of one or more materials from the group including biocompatible plastics, biodegradable materials, bioresorbable materials, biomaterials, or can be composed of one or more materials from the group, biocompatible plastics such as polymers from the group including cellulose, collagen, albumin, casein, polysaccharide (PSAC), polylactide (PLA), poly-L-lactide (PLLA), polyglycolic acid (PGA), poly-D,L-lactide-co-glycolide (PDLLA-PGA), polyhydroxybutyrate (PHB), polyhydroxyvalerate (PHV), polyalkyl carbonate, polyorthoester, polyethylene terephthalate (PET), polymalonic acid (PML), polyanhydride, polyphosphazene, polyamino acids and their copolymers, hyaluronic acid (in this case, depending on the desired properties, in pure form, in derivative form, in blend form or as a copolymer), biomaterials such as natural dried tissues, such as pericardium.

[0016] The body can consist of or contain a biocompatible material and / or a biodegradable material, wherein the material includes at least one material selected from the group including metallic biodegradable materials (especially based on magnesium or magnesium alloys, such as WE43, magnesium-zinc-aluminum, magnesium-aluminum or magnesium-zinc-calcium), shape memory alloys (such as nitinol) and the above-mentioned biodegradable plastics.

[0017] Biodegradation should be understood as the hydrolysis, enzymatic and other metabolic degradation processes in living organisms, which are mainly caused by the contact of body fluids with the implant and result in the gradual dissolution of at least most of the body or the implant. The term bio-corrosion is usually used synonymously with the term biodegradation. The term bioresorption includes the subsequent resorption of degradation products by living organisms. The purpose of using biodegradable implants is that they are degraded by the organism at the time point when they are no longer needed, for example, in terms of their supporting role, and thus no longer exist as foreign bodies in the organism for more than the necessary time.

[0018] In an exemplary embodiment of the covering having a connecting portion in the covering element, the connecting portion can be circumferentially adjacent to the folding portion of the covering including a first zigzag fold and at least one second zigzag fold, such that the connecting portion and the folding portion do not overlap. In the region of the connecting portion, only two superposed layers of the covering material are present, while in the region of the zigzag fold, three superposed layers of the covering material are arranged. This results in a relatively small outer diameter of the implant having the covering.

[0019] In another exemplary embodiment of the covering with the connecting part, the connecting part overlaps at least one fold formed by the first zigzag fold and / or at least one second zigzag fold. This means that the connecting part is part of a zigzag fold or two adjacent zigzag folds. However, in this case, the fold edges are not arranged in the region of the connecting part, but extend circumferentially next to the connecting part. Regarding this exemplary embodiment, the connecting part can be arranged at least partially below at least one fold formed by the first zigzag fold and / or at least one second zigzag fold with respect to the radial direction of the covering. This means that the connecting part is arranged on the inner side (with respect to the radial direction) of the fold of the first zigzag fold and / or the fold of the second zigzag fold. Alternatively, the connecting part can at least partially surround externally at least one fold formed by the first zigzag fold and / or at least one second zigzag fold with respect to the radial direction of the covering. In this exemplary embodiment, the connecting part can be arranged on the outer side (with respect to the radial direction) of the fold of the first zigzag fold and / or the fold of the second zigzag fold. In these exemplary embodiments, the connecting part is integrated into the fold such that during the expansion of the covering, the behavior of the connecting part is more evenly loaded. However, the arrangement of the connecting part in the region of the zigzag fold increases the number of superimposed layers of the covering material, such that the outer diameter of the implant increases compared to the variant in which the connecting part is arranged circumferentially next to the zigzag fold.

[0020] The above problem is additionally solved by an implant having a body forming a circumferential and perforated lateral surface, wherein the body has a compressed state and is configured to transition to an expanded state, and wherein the lateral surface in the compressed state of the body at least partially covers a covering as described above. Such an implant can be, for example, a stent, a stent graft, an emergency stent, the stent part of a prosthetic heart valve. In one exemplary embodiment, the body consists of a plurality of interconnected struts that form a substantially hollow cylindrical shape when compressed. In principle, such bodies have been described in detail in various variants and will therefore not be discussed in more detail below. For example, the struts can form an annular part consisting of units (meshes) formed by a plurality of struts (rods, strips), such as struts forming a zigzag or meandering structure. Here, two or more than two struts can meet at so-called nodes. The annular parts can be connected to each other by additional struts.

[0021] In particular, the body of the implant has two states, namely a compressed state and an expanded state. In particular, the body has a compressed state or an expanded state, and the body is configured to be able to transition from the compressed state to the expanded state and vice versa.

[0022] The body presents at least two states, namely a compressed state with a small outer diameter and an expanded state with a larger outer diameter. In particular, the body has a compressed state or an expanded state, and the body is configured to be able to transition from the compressed state to the expanded state and vice versa. In the compressed state, the catheter can be used to guide the implant through a stenotic vessel into a vessel to be treated and positioned at the treatment site. The transition from the compressed state to the expanded state is performed by expanding the structure of the body, for example with the aid of a balloon. The expansion of the support structure causes the stent to unfold. Alternatively, the transition to the expanded state occurs in the self-expanding body when a transition temperature is exceeded.

[0023] In the context of explaining the present invention, the term "vessel" is used to refer to all blood vessels, organs or other body cavities of a patient into which a universal implant may be inserted for treatment.

[0024] Furthermore, the above mentioned problem is solved by a method for producing the above mentioned covering, the method comprising the following steps:

[0025] ● providing an unfolded tubular covering element having a predetermined length in the longitudinal direction,

[0026] ● Folding a covering element for producing a covering so that the material is laid along the circumferential direction in a first zigzag fold and at least one second zigzag fold, the first zigzag fold and the at least one second zigzag fold being arranged adjacent to each other in the circumferential direction and configured so that in each case two adjacent zigzag folds of the first zigzag fold and of the at least one second zigzag fold in the circumferential direction are folded mirror-symmetrically about an imaginary mirror plane, which extends between the two adjacent zigzag folds and in the longitudinal direction of the tube transversely to the circumferential direction.

[0027] This is a particularly simple production process for the covering described in detail above. This has the advantages outlined above.

[0028] In an exemplary embodiment, the folded covering can be fixed by means of a fixing bath so that it is dimensionally stable and retains its shape and / or folding even when the implant is produced.

[0029] As already described above, in an exemplary embodiment, the unfolded tubular covering element can be produced by arranging the two end portions of the flat covering element one above the other and firmly connecting these superposed end portions in the longitudinal direction of the tube. Alternatively, the covering element is produced directly in tubular form.

[0030] Furthermore, the above mentioned problem is solved by a method for producing the above mentioned implant, wherein the above mentioned method is used for producing a covering. Furthermore, the following steps are carried out:

[0031] ● provide the subject in a compressed state,

[0032] ● Place the compressed body within the internal free space of the folded or unfolded covering element.

[0033] In an exemplary embodiment, after folding the covering element, the body can be placed within the free space of the element. These individually performed process steps (producing the folded covering and mounting it on the compressed, e.g., coiled body) can ensure that the properties of the balloon of the balloon catheter are not affected by the chemicals of the fixing bath, and then the implant is placed on the balloon catheter for transportation to the treatment site of the patient. Alternatively, when the compressed body is already within the internal free space of the tubular covering element, folding and, if necessary, fixing can be carried out.

[0034] The present invention will be explained below based on exemplary embodiments and with reference to the drawings. In this context, all features described and / or shown, individually or in any combination, form the subject matter of the present invention, and are independent of their recitation in the claims or the dependent reference of the claims. Description of the Drawings

[0035] The drawings schematically show:

[0036] Figure 1 A first exemplary embodiment of an implant according to the present invention in an expanded state in a perspective view from the side,

[0037] Figure 2 An exemplary embodiment of the body of the implant in an expanded state in a perspective view from the side,

[0038] Figure 3 In a perspective view from the side in a compressed state according to Figure 2 the body,

[0039] Figure 4 An exemplary embodiment of the covering element before folding in a perspective view from the side,

[0040] Figure 5 A first exemplary embodiment of a covering according to the present invention in a perspective view from the side,

[0041] Figure 6 In a view from the front according to Figure 5 a part of the covering,

[0042] Figure 7 A second exemplary embodiment of a covering according to the present invention in a view from the front,

[0043] Figure 8 In a perspective view from the side according to Figure 7Exemplary embodiments of the covering

[0044] Figure 9 In a perspective view from the side, a third exemplary embodiment of the covering according to the invention

[0045] Figure 10 In a view from the front, a fourth exemplary embodiment of the covering according to the invention, and

[0046] Figure 11 Z - fold from a perspective view from the side. Detailed Description

[0047] The present invention will be explained below based on a covered stent. It can also be used in the same or similar manner for the other implants mentioned above.

[0048] Figure 1 An implant according to the invention is shown, in the form of a covered hollow cylindrical stent, which has a body 5 consisting of a plurality of struts 7 and a covering 10 in the expanded state. The covering 10 is arranged on the perforated lateral surface of the body 5. The covering 10 has a length L in the longitudinal direction, which is slightly less than the length of the body 10.

[0049] By way of example, Figure 2 and Figure 3 shows another example of a hollow cylindrical body 55 in the expanded state ( Figure 2 ) and the compressed state ( Figure 3 ). It can be clearly seen from Figures 1 to 3 that the bodies 5, 55 are known to be composed of parts having struts 7, 57 arranged in a zig - zag or meandering shape.

[0050] The coverings explained below are suitable for being mounted on the bodies 5, 55 in the compressed state in the configurations shown in each case, especially in the folds shown. This configuration is particularly suitable for low - stretch covering materials (such as pericardium), which are used because of their good properties, such as with respect to biocompatibility. Due to the symmetric folding, an implant with a covering having the configuration shown and applied to the compressed body can be expanded with a small force, since the forces that occur are distributed over the symmetrically arranged and configured folded parts.

[0051] To manufacture the covering, first a Figure 4 shown unfolded covering element 10a is provided. The covering element 10a is, for example, a pericardial tube having a connecting part 16. The connecting part 16 is formed by superimposing and firmly connecting two end parts of a sheet - like pericardial piece, for example by means of cross - linking. The connecting part 16 extends along the entire length L of the covering element 10a.

[0052] Alternatively, the folding of the covering element 10a can also be performed during the manufacture of the covering element 10a, for example by an embossing process.

[0053] Subsequently, the covering element 10a is folded along the circumferential direction U so that two zigzag folds 11, 12 are formed, which are folded in the form of Figure 5 For each zigzag fold 11, 12, the wall of the covering element 10a is folded twice, first in one direction and then in the opposite direction (relative to the circumferential direction). The first zigzag fold 11 is arranged in Figure 5 In order to better illustrate the figure, it is marked with a dot-dash line 11a, and in Figure 6 In the figure, it is shown separately in a front view (also corresponding to a cross section). Each zigzag fold has two fold edges, which are marked as 11b and 11c relative to the first zigzag fold 11. The fold edges 11b, 11c are oriented in opposite directions along the circumferential direction U, that is, they are closed or opened in opposite directions. Each zigzag fold 11, 12 has three superimposed covering material layers in the corresponding folded portion. In practice, unlike what is shown in the figure, they are directly located on top of each other so that they are in contact with each other. The interval representation is provided here for better explanation.

[0054] The first zigzag fold 11 and the second zigzag fold 12 are arranged adjacent to each other in the covering 10 along the circumferential direction U and along the entire length L, and the folding of the second zigzag fold 12 is mirror-symmetrical to the folding of the first zigzag fold 11 relative to the imaginary mirror plane 17. The imaginary mirror plane extends transversely to the circumferential direction U, between the first zigzag fold 11 and the second zigzag fold 12 and along the entire length L of the covering 10. In the region of the mirror plane 17, an opening is formed between the folding edge 11c of the first zigzag fold 11 and the folding edge 12c of the second zigzag fold 12, which facilitates the unfolding of the covering 10.

[0055] The connecting portion 16 is also arranged so that it does not overlap the first zigzag fold 11 or the second zigzag fold 12 in the circumferential direction U. In this way, a particularly small outer diameter of the covering 10 can be achieved, since a maximum of three layers of covering material are placed on top of each other in the region of the zigzag folds 11, 12.

[0056] After the corresponding folding, the covering 10 can be fixed by means of a fixing bath. Subsequently, the compressed body 5, 55 is placed in the inner free space 18 of the covering 10, or the covering 10 is mounted on the perforated lateral surface of the compressed body 5, 55. The implant is thus prepared and ready for insertion into the patient's body. For insertion, the implant can be mounted on a catheter, for example on a balloon of a catheter. For the intended use, the stent graft with the covering 10 is delivered via a catheter to the site to be treated in the patient's blood vessel. There, for example by inflation of the balloon, the body 5, 55 of the stent is expanded / enlarged and thereby also the covering 10 is unfolded so that after completion of the expansion process it is as follows. Figure 1 As shown, it is arranged on the body 5. Due to the mirror-symmetrical arrangement of the first zigzag fold 11 and the second zigzag fold 12, only a small force is required to unfold the cover 10, and this force is also evenly distributed on the two zigzag folds 11, 12. Therefore, no pulling force occurs at a specific point, so that the unfolding is carried out evenly.

[0057] exist Figure 7 and 8 The second exemplary embodiment of a covering 20 according to the invention shown in FIG. 1 has a total of four zigzag folds 21, 22, 23 and 24, which are arranged adjacent to one another along the circumferential direction U. In each case, two adjacent zigzag folds 21, 22; 22, 24; 24, 23; 23, 21 are folded in a mirror-symmetrical manner similar to the zigzag folds 11, 12 of the first exemplary embodiment of the covering. Figure 7 In the embodiment of the present invention, two imaginary mirror planes 27 are shown by way of example. In addition, in this exemplary embodiment, the connecting portion 26 overlaps with two zigzag folds 23, 24, wherein the folded edges 23b, 24b of the zigzag folds 23, 24 are arranged to be circumferentially adjacent to the connecting portion 26. This is advantageous because the flexibility of the two-layer connecting portion 26 is lower than that of the (single-layer) covering material. The unfolding of the covering 20 can be even more symmetrical than in the first exemplary embodiment of the covering 10, because the tensile forces are even more evenly distributed over the entire circumference. However, this exemplary embodiment of the covering 20 has a larger circumference, because in the region of the zigzag folds 23, 24, the covering material has four layers. In addition, this exemplary embodiment is very suitable for the mechanization or automation of the installation of the covering 20.

[0058] Similar to the first exemplary embodiment, in Figure 9 and 10 The exemplary embodiments for coverings 30, 40 shown in FIG. 1 each have two zigzag folds 31, 32 or 41, 42 arranged adjacent to each other in the circumferential direction. The connecting portions 36, 46 overlap the two zigzag folds 31, 32 and 41, 42, respectively, wherein the connecting portions 36, 46 overlap the two zigzag folds 31, 32 and 41, 42, respectively. Figure 9In the third exemplary embodiment of the covering 30 shown, the connecting portion 36 forms the outer portions of the zigzag folds 31, 32 as viewed in the radial direction, while in Figure 10 In the fourth exemplary embodiment shown, the connecting portion 46 forms the inner portions of the zigzag folds 41, 42. In the third exemplary embodiment of the covering 30, the connecting portion 36 abuts against the zigzag folds 31, 32, thus forming protection for these folds, for example, during the mounting to the body. In contrast, the folds of the zigzag folds 41, 42 surround the connecting portion 46 like flower buds, which has the advantages of better feedability and better cross characteristics.

[0059] The fourth exemplary embodiment of the covering 40 is very similar to Figure 5 the first exemplary embodiment shown therein, because the folds in the circumferential direction U are longer in the Figure 10 exemplary embodiment compared to the latter.

[0060] In all exemplary embodiments of the coverings 20, 30, 40, the compression bodies 5, 55 are mounted in the corresponding free spaces inside the coverings 20, 30, 40 similar to the first exemplary embodiment and expand after being arranged at the treatment site. During this process, the coverings 20, 30, 40 unfold similar to the first exemplary embodiment.

[0061] The bodies 5, 55 of the implant can be composed of, for example, nitinol or cobalt-chromium alloy, which changes to an expanded state when the transition temperature is exceeded. The coverings 10, 20, 30, 40 are made of pericardium, for example.

Claims

1. A tubular covering (10, 20, 30, 40) for an implant, wherein, The coverings (10, 20, 30, 40) are arranged along the circumferential direction (U) of the tube with a first zigzag fold (11, 21, 31, 41) and at least one second zigzag fold (12, 22, 23, 24, 32, 42), the first zigzag fold (11, 21, 31, 41) and the at least one second zigzag fold (12, 22, 23, 24, 32, 42) being arranged adjacent to each other in the circumferential direction (U) and configured such that two adjacent zigzag folds in the circumferential direction (U) of the first zigzag fold (11, 21, 31, 41) and the at least one second zigzag fold (12, 22, 23, 24, 32, 42) are folded mirror-symmetrically with respect to an imaginary mirror plane (17, 27), the imaginary mirror plane (17, 27) being between the respective two adjacent zigzag folds and extending transversely to the circumferential direction (U) in the longitudinal direction of the tube.

2. The covering (10, 20, 30, 40) according to claim 1, characterized in that, The covering has a first zigzag fold (11, 21, 31, 41) and a second zigzag fold (12, 22, 23, 24, 32, 42) or a first zigzag fold (21), a second zigzag fold (22), a third zigzag fold (23) and a fourth zigzag fold (24) or a plurality of 2×N zigzag folds, where N >= 3, where all the zigzag folds are arranged adjacent to each other in the circumferential direction (U), and where, in each case, two adjacent zigzag folds in the circumferential direction (U) are folded mirror-symmetrically with respect to the imaginary mirror plane (17, 27), the imaginary mirror plane (17, 27) being arranged between the respective two zigzag folds.

3. The covering (10, 20, 30, 40) according to any one of the preceding claims, characterized in that, The first zigzag fold (11, 21, 31, 41) and the at least one second zigzag fold (12, 22, 23, 24, 32, 42) are arranged such that the covering forms an internal, substantially cylindrical free space (18, 28, 38, 48).

4. The covering (10, 20, 30, 40) according to any one of the preceding claims, characterized in that, The covering includes a connecting portion in which a first layer of the covering material and a second layer of the covering material are stacked on top of each other and attached to each other along the longitudinal direction of the covering.

5. The covering (10) according to claim 4, characterized in that, The connecting portion is arranged circumferentially adjacent to a folding portion of the covering including the first zigzag fold (11) and the at least one second zigzag fold (12) such that the connecting portion and the folding portion do not overlap.

6. The covering (20, 30, 40) according to claim 4, characterized in that, The connecting portion overlaps at least one fold formed by the first zigzag fold (21, 31, 41) and / or the at least one second zigzag fold (22, 23, 24, 32, 42).

7. The covering (40) according to any one of claims 4 and 6, characterized in that, The connecting portion is arranged at least partially below the at least one fold formed by the first zigzag fold (41) and / or the at least one second zigzag fold (42) with respect to the radial direction of the covering.

8. The covering (20, 30) according to any one of claims 4 and 6, characterized in that, The connecting portion at least partially surrounds externally the at least one fold formed by the first zigzag fold (21, 31) and / or the at least one second zigzag fold (22, 23, 24, 32) with respect to the radial direction of the cover.

9. An implant, comprising a body (5, 55) forming a circumferential and perforated lateral surface, wherein, The body (5, 55) has a compressed state and is configured to transition to an expanded state, wherein, in the compressed state of the body (5, 55), the lateral surface is at least partially covered by a cover (10, 20, 30, 40) according to any of the preceding claims.

10. The implant according to claim 9, wherein, The body (5, 55) is composed of a plurality of interconnected struts (7, 57) which, when compressed, form a substantially hollow cylindrical shape.

11. A method for manufacturing a covering (10, 20, 30, 40) according to any one of claims 1 to 8, the method comprising the following steps: providing an unfolded tubular covering element (10a) having a predetermined length (L) in said longitudinal direction, · Folding the covering element so that the material is placed along the circumferential direction (U) in the form of a first zigzag fold (11, 21, 31, 41) and at least one second zigzag fold (12, 22, 23, 24, 32, 42), the first zigzag fold and the at least one second zigzag fold being arranged adjacent to each other in the circumferential direction (U) and being configured so that in each case two adjacent zigzag folds of the first zigzag fold (11, 21, 31, 41) and of the at least one second zigzag fold (12, 22, 23, 24, 32, 42) are folded mirror-symmetrically with respect to an imaginary mirror plane (17, 27), the imaginary mirror plane being between two adjacent zigzag folds and extending transversely with respect to the circumferential direction (U) in the longitudinal direction of the tube.

12. The method according to claim 11, wherein The unfolded tubular covering element is produced by arranging two end sections of a flat covering element one above the other and firmly connecting these superposed end sections in the longitudinal direction of the tube.

13. A method for producing an implant according to any one of claims 9 to 10, comprising the steps of the method according to claims 11 and 12 and the following step: providing the body (5, 55) in said compressed state, • Arranging the compressed body (5, 55) within the inner free space (18, 28, 38, 48) of a folded cover (10, 20, 30, 40) or an unfolded covering element.

14. The method according to claim 13, wherein After folding the cover (10, 20, 30, 40), the body (5, 55) is located in the free space (18, 28, 38, 48) of the cover (10, 20, 30, 40).

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