Medical device, medical kit and manufacturing method for introduction into a hollow body organ

Abstract

The invention relates to a medical device, in particular a stent, for introduction into a hollow body organ, having a compressible and expandable mesh structure (10) consisting of mesh elements (11, 12, 13, 14), the mesh structure having at least one closed unit ring (34), the unit ring comprising at most 12, in particular at most 10, in particular at most 8, in particular at most 6 units (30) directly adjacent in the circumferential direction of the mesh structure (10). The invention is characterized in that the mesh structure (10) is at least partially provided with a covering (40) made of an electrospun fabric having pores (41) of irregular size, wherein the covering (40) has a diameter of 100,000 μm. 2 The area has a size of at least 15 μm 2 At least 10 pores.

Description

[0001] The invention relates to a medical device, in particular a stent, for introduction into a hollow body organ according to the preamble of claim 1. The invention also relates to a medical kit and a production method. A medical device of the type mentioned at the outset is known, for example, from WO 2014 / 177634 A1 from the applicant.

[0002] WO 2014 / 177634 A1 describes a highly flexible stent having a compressible and expandable lattice structure, wherein the lattice structure is formed in one piece. The lattice structure comprises closed cells, each of which is defined by four lattice elements. The lattice structure has at least one cell ring, which comprises three to six cells.

[0003] In addition, from the practice of the present applicant, stents with a mesh structure formed by a single wire are also known. The wire is interwoven with itself to form a tubular mesh. The wire is bent at the axial end of the tubular mesh to form a loop with a non-invasive effect. The axial end can be expanded in a funnel shape.

[0004] The known medical device is particularly suitable for treating aneurysms in small blood vessels of the brain. Such blood vessels have a very small cross-sectional diameter and are usually very tortuous. For this reason, the known stent is designed to be highly flexible so that on the one hand the stent can be compressed to a very small cross-sectional diameter, and on the other hand the stent has a high degree of bending flexibility that can be delivered into small blood vessels of the brain.

[0005] Advantageously, for the treatment of cerebral vascular aneurysms, a stent is used that spans the aneurysm and isolates the aneurysm from the blood flow in the blood vessel. In order to achieve this, known stents are provided with a covering that closes the stent unit, thereby preventing blood from flowing into the aneurysm. Such a covering is usually made of a textile material. However, in combination with the stent structure, the wall thickness of the stent is relatively large, which limits the compressibility of the stent. Moreover, the covering limits compression to a smaller cross-sectional diameter, which in turn hinders the delivery of the stent to the small blood vessels of the brain. Returning to the applicant's EP 2 946 750 B1, an attempt is made to utilize a textile covering to solve the compressibility of the stent by providing a fiber bundle of a textile material composed of loosely arranged monofilaments.

[0006] Textile-type structures are known from the prior art which are suitable for covering aneurysms. In particular, EP 2546 394 A1 shows such a covering, a so-called graft, which has an electrostatically spun structure. In order to achieve a particularly low porosity Multiple layers of this electrospun structure were stacked. However, this resulted in thicker walls, which hindered delivery into highly tortuous small blood vessels.

[0007] From WO 02 / 49536 A2, an electrospun structure is also known, which has two layers of electrospun fabric, wherein the two layers have different porosities. Here, too, the wall thickness is relatively large, thus limiting the compressibility of the electrospun structure.

[0008] EP 2 678 446 B1 relates to a stent for neurovascular applications covered with a nonwoven. The nonwoven is produced by electrospinning and comprises a plurality of layers, wherein the inner layer is impermeable to liquids and the outer layer is configured to be sponge-like. The nonwoven thus forms a membrane that is very difficult for liquids to penetrate and has an increased wall thickness due to the sponge-like layer, which affects the compressibility of the stent.

[0009] Against this background, the object of the present invention is to provide a medical device, in particular a stent, for introduction into a hollow body organ, which can be compressed to be very small and at the same time provides better isolation of the aneurysm. Another object of the present invention is to provide a production method.

[0010] According to the invention, the object with respect to the medical device is achieved by the subject matter of claim 1 , the object with respect to the medical set is achieved by the subject matter of claim 36 , and the object with respect to the production method is achieved by the subject matter of claim 37 .

[0011] The present invention is therefore based on the idea of ​​providing a medical device, in particular a stent, for introduction into a hollow body organ, which has a compressible and expandable mesh structure consisting of mesh elements. The mesh structure has at least one closed unit ring, which includes at most 12, in particular at most 10, in particular at most 8, in particular at most 6 units that are adjacent in the circumferential direction of the mesh structure. In particular, the unit ring may include at least 3 units that are directly adjacent in the circumferential direction of the mesh structure. The mesh structure is at least partially provided with a covering made of an electrospun fabric having pores of irregular size. The covering has a diameter of 100,000 μm. 2 The area includes a size of at least 15 μm 2 At least 10 pores.

[0012] Particularly preferably, the coating has a thickness of 100,000 μm. 2 The area includes a size of at least 30 μm 2 At least 10 pores.

[0013] In particular, it can be provided that the inscribed circle diameter of at least 10 pores is at least 4 μm, in particular at least 5 μm, in particular at least 6 μm, in particular at least 7 μm, in particular at least 8 μm, in particular at least 9 μm, in particular at least 10 μm, in particular at least 12 μm, in particular at least 15 μm, in particular at least 20 μm. The inscribed circle diameter is the diameter of the largest possible circle that can be inscribed in the pore. In other words, the inscribed circle diameter of a pore corresponds to the outer diameter of a cylinder that can be pushed just through this pore.

[0014] The invention combines a highly flexible lattice structure as a support structure with a cover that has a high permeability or porosity and is particularly thin and flexible due to its manufacturing process. In this respect, the medical device as a whole is highly compressible and can be introduced well into very small blood vessels.

[0015] In particular, the high flexibility of the support structure or grid structure is achieved in the following manner, that is, the grid structure has a closed unit ring, and the closed unit ring has at most 12 units directly adjacent in the circumferential direction of the grid unit. The closed unit ring also enables the grid structure to be retracted into the catheter after partial release, because the grid element cannot hook and protrude at the tip of the catheter due to the closed structure. In particular, all unit rings of the grid structure can have at most 12, in particular at most 10, in particular at most 8, in particular at most 6 units directly adjacent in the circumferential direction of the grid structure. All unit rings can include at least 3 units directly adjacent in the circumferential direction of the grid structure.

[0016] By limiting the cells to a cell ring in the circumferential direction, the grid elements and their connections or intersections are also limited. Due to the limited number of grid elements in the circumferential direction, the grid structure can be compressed to a small cross-sectional diameter, wherein the grid elements preferably lie directly against each other. In addition, limiting the cells in the circumferential direction can also achieve increased bending flexibility, so that the grid structure, especially also in the compressed state, can be guided through narrow and tortuous blood vessels with the help of a catheter.

[0017] Preferably, the mesh elements define closed cells of the mesh structure, wherein each closed cell is defined by four mesh elements each. The closed cells achieve a high stability of the mesh structure, which facilitates the function of the mesh structure as a carrier of the covering. In particular, a high stability is achieved in the axial direction, i.e. in the direction of the longitudinal axis of the mesh structure, which improves the delivery of the medical device through the catheter. In the radial direction, due to the closed cells, the mesh structure may have an increased flexibility, which results in an improved radial force.

[0018] In the expanded state, the medical device according to the present invention can achieve good isolation of the aneurysm, but at the same time allows nutrients to be supplied to the aneurysm. The medical device also achieves the supply of nutrients to the inner wall of the branch vessels and adjacent blood vessels. The covering made of electrospun fabric can achieve coverage of the aneurysm, but at the same time allows a certain degree of permeability of blood. This permeability is conducive to the supply of nutrients to the cells of the aneurysm wall. Thus, cell degeneration and possible aneurysm rupture caused by it are avoided.

[0019] In electrospun fabrics, the pores are usually designed to be irregular. In any case, the manufacturing method does not allow the establishment of a patterned arrangement or design of the pores. However, the pore size can be set at least to the extent that at least a portion of the pores has a certain minimum size according to the process parameters. According to the invention, in this respect, it is proposed that at least a portion of the pores have a certain minimum size. 2 There is a minimum number of pores in an area of ​​100,000 μm, and these pores have a minimum size. 2 At least 10 pores are arranged on an area of ​​at least 15 μm. 2 , in particular at least 30 μm 2 This combination of a certain minimum number of pores and a minimum size of these pores has been shown in practice to be particularly advantageous for sufficient blood permeability of the covering with a simultaneously good covering effect.

[0020] During the manufacture of the covering, the minimum size of the pores can be set in particular by the process duration of the electrospinning. In addition, the covering made of electrospun fabric is very thin and flexible, which supports the flexibility of the grid structure. In particular, unlike previously known coverings made of other textile materials, the covering hardly hinders the compression of the grid structure. Therefore, in general, the entire medical device according to the invention can be compressed to an extremely small cross-sectional diameter and can therefore be introduced into particularly small blood vessels through a small catheter.

[0021] Therefore, with the medical device according to the invention, vascular treatments that are not possible with current medical devices with a grid structure and a covering can also be achieved. Due to the high compressibility of the device according to the invention, very small delivery forces (Zuführkraft) are generated during delivery through the catheter. In addition, the material of the covering can also contribute to reducing the delivery forces. In particular, the delivery forces in the device with the covering can be the same or smaller than when the grid structure is delivered alone. In any case, the delivery forces in the device with the covering are at most 50%, in particular at most 25%, in particular at most 10% greater than when the grid structure is delivered alone.

[0022] The advantages of the present invention are further improved by the fact that the preferred coating is 100,000 μm 2 The area includes at least 15 pores, and the size of these pores is at least 30 μm 2 , in particular at least 50 μm 2 , in particular at least 70 μm 2 , in particular at least 90 μm 2 . It is also beneficial that the covering is 100,000 μm 2 The surface of the substrate comprises at least 15, in particular at least 20, in particular at least 25 pores having a size of at least 30 μm. 2 .

[0023] In order to ensure that the permeability of the covering is not too great, ie to achieve a medically meaningful separation of the aneurysm from the blood flow in the vessel, it is provided in a preferred embodiment of the invention that the size of the pores is a maximum of 750 μm. 2 , especially up to 500μm 2 , especially up to 300μm 2 .

[0024] The covering can be firmly, in particular materially connected to the grid structure. In particular, it can be provided that the covering is applied directly to the grid structure. For example, an electrospinning process can be carried out directly on the grid structure so that a connection to the grid structure is established while forming the covering. The covering can be materially connected to the grid structure. For example, the covering can be connected to the grid structure by an adhesive connection. The adhesive connection can be produced by an adhesive agent. For example, the adhesive agent can include or consist of polyurethane.

[0025] The strong connection between the cover and the grid structure prevents the cover from being detached from the grid structure during delivery of the medical device through the catheter. At the same time, this facilitates the positioning of the medical device under radiological control, since it is sufficient to apply corresponding radiological markers on the grid structure or the cover. Since the relative position between the cover and the grid structure is constant, no additional radiological markers are required that can identify the relative displacement between the cover and the grid structure. In summary, the number of radiological markers (e.g., radiological marker sleeves) can be reduced, which in turn has a positive effect on the compressibility of the medical device.

[0026] The grid elements of the grid structure can be coated with an adhesion promoter, in particular polyurethane. In particular, it can be provided that the adhesion promoter forms a material-fit connection between the cover and the grid structure. Preferably, the adhesion promoter surrounds the entire grid element, thereby forming a coating for the grid element.

[0027] In a preferred embodiment of the present invention, it is proposed that the grid structure at least partially forms a cylindrical and / or funnel-shaped hollow body. The substantially cylindrical hollow body enables the grid structure to be close to the vessel wall of the blood vessel. The funnel-shaped hollow body can be used, for example, to capture thrombi within a blood vessel or to treat blood vessels of different diameters. In this regard, it should be noted in the context that the medical device can preferably be configured as a permanent implant, in particular a permanent implant in the form of a stent that can be implanted durably, or can be configured as a thrombectomy device (Thrombektomiedevice), wherein the thrombectomy device preferably remains firmly connected to the delivery wire and is only temporarily released in the blood vessel.

[0028] In a preferred improvement of the lattice structure which is constructed as a hollow body, it is provided that the hollow body can be This configuration of the lattice structure enables the medical device to be used as a stent or flow diverter, which barely impedes blood flow through the vessel in the longitudinal direction, but blocks blood flow into the branch aneurysm by means of the covering or at least reduces the flow impact.

[0029] However, it is also conceivable in principle that the grid structure is provided with closed ends. In particular, at least one longitudinal end of the grid structure is closed. Both longitudinal ends of the grid structure can also be closed. Preferably, it is proposed that the closure at the longitudinal ends is achieved by a funnel-shaped gathering of the grid structure. In this case, the covering can also be arranged in the funnel-shaped region of the grid structure.

[0030] In a preferred embodiment of the invention, it is proposed that the covering is arranged on the outer side of the lattice structure. In this case, the lattice structure forms a support structure that exerts a radial force sufficient to fix the covering to the vessel wall. In this regard, the support structure supports the covering arranged on the outside. Alternatively, the covering can also be arranged on the inner side of the lattice structure.

[0031] Alternatively or additionally, the cover can be arranged on the inner side of the grid structure. In particular, the grid structure can be embedded between two covers, which are respectively formed by electrostatic spinning fabrics. In this regard, the grid cells of the grid structure can be completely covered with electrostatic spinning fabrics. Specifically, it can be proposed that the electrostatic spinning fabric on the inner side of the grid structure of the cover passes through the cells of the grid structure and is connected to the electrostatic spinning fabric on the outer side of the grid structure of the cover. Therefore, the grid elements defining the cells are covered with electrostatic spinning fabrics on all sides.

[0032] Preferably, it is proposed that the cover is formed from a plastic material, in particular a polyurethane, in particular Pellethane (brand name for polyurethane from the company Lubrizol). This material is particularly light and can be easily produced into fine threads by electrospinning. Plastic materials also make it possible, on the one hand, to produce particularly thin and fine-porous covers. On the other hand, the plastic material itself already has a high degree of flexibility, so that a high degree of compressibility of the medical device is achieved.

[0033] It is also advantageous if the covering is formed of threads arranged in an irregular mesh, the thread thickness of the threads being between 0.1 μm and 3 μm, in particular between 0.2 μm and 2 μm, in particular between 0.5 μm and 1.5 μm, in particular between 0.8 μm and 1.2 μm.

[0034] Particularly preferably, the medical device is a stent for treating aneurysms in arterial vessels, in particular in neurovascular vessels. Preferably, the cross-sectional diameter of the vessel can be between 1.5 mm and 5 mm, in particular between 2 mm and 3 mm. It is also possible to treat vessels with a cross-sectional diameter of 4 mm to 8 mm. For example, the carotid artery has such a cross-sectional diameter.

[0035] In general, the medical device can be a stent for treating saccular or fusiform aneurysms. In particular in the case of fusiform aneurysms, i.e. aneurysms extending over the entire circumference of a blood vessel, it is advantageous to use a structure with targeted fine pores to propagate endothelial cells. Thus, reconstruction of the missing vessel wall can be achieved. Specifically, the structure formed by the electrospun fabric with a specific pore size forms a stent for the propagation of endothelial cells, which can then form a new, closed vessel wall.

[0036] In contrast to conventional flow diverter structures, electrospun structures have openings defined by intersecting metal wires that vary in shape and size depending on vessel diameter and implant manipulation, and therefore do not provide reproducible conditions for cell proliferation.

[0037] With regard to the permeability and homogeneity of the covering, it is advantageous if at least 60%, in particular at least 70%, in particular at least 80% of the area of ​​the covering is formed by pores, the size of which is at least 5 μm. 2 , in particular at least 10 μm 2 In particular, at least 30% of the area of ​​the covering may be composed of particles having a size of at least 30 μm. 2 It is also possible that at least 40%, in particular at least 50%, in particular at least 60%, in particular at least 70%, in particular at least 80% of the area of ​​the covering consists of pores having a size of at least 30 μm. 2The above values ​​have proven to be advantageous in order to provide a covering with a certain minimum permeability, thereby achieving an adequate supply of nutrients to the cells in the aneurysm.

[0038] In order to make the covering sufficiently dense to isolate the aneurysm from the blood flow of the vessel to the extent that further expansion of the aneurysm is prevented, it has proven advantageous if a maximum of 20% of the area of ​​the covering consists of particles having a size of at least 500 μm. 2 Alternatively or additionally, a maximum of 50% of the area of ​​the covering may be formed by pores having a size of at least 300 μm. 2 of pore formation.

[0039] In principle, the mesh structure can be constructed as a one-piece mesh structure. The mesh structure can also be formed by wires that are interwoven with each other. In this regard, it is proposed in a preferred embodiment that the mesh elements form ribs (Steg), which are connected to each other into one piece (a one-piece mesh structure) by rib connectors. Alternatively, the mesh elements can form wires that are interwoven with each other (a woven mesh structure). The woven mesh structure is characterized by particularly high flexibility, in particular bending flexibility, while the one-piece mesh structure has a relatively thin wall thickness, so the mesh structure has little effect on the blood flow in the blood vessels.

[0040] It is particularly preferred that the braided mesh structure is formed from a single wire that is bent at the axial end of the tubular mesh structure and forms an atraumatic terminal loop. The wire can have a radiopaque core material and a sheath material made of a shape memory alloy. In particular, it is proposed that the volume ratio between the core material (preferably platinum) and the volume of the entire composite wire is between 20% and 40%, in particular between 25% and 35%.

[0041] At the axial ends, the mesh structure can expand radially, in particular in a funnel shape (flaring). The flaring angle is preferably between 50° and 70°, in particular between 55° and 65°. The units can be arranged in unit rings extending in the circumferential direction of the woven mesh structure, wherein the rings each have 6 to 12 units, in particular 6 to 10 units.

[0042] In general it is preferably provided that the mesh structure (single-piece or woven) is self-expandable.

[0043] The elongation of the covering according to ASTM 412 may be between 300% and 550%, in particular between 350% and 500%, in particular between 375% and 450%. According to ASTM 412, the elastic modulus (E-Modul) of the covering may be:

[0044] When the elongation is 50%: >15-21MPa(psi)

[0045] When the elongation is 100%: >18<26MPa(psi)

[0046] When the elongation is 300%, >32<41MPa(psi).

[0047] The Shore hardness of the covering according to ASTM D 2240 may be between 80A and 85D, in particular between 90A and 80D, more particularly between 55D and 75D.

[0048] To improve the repositionability, the covering may return to its original configuration, in particular its unfolded configuration, after compression and re-release of the grid structure.

[0049] The threads or individual threads of the fabric can be connected to each other in a materially fitting manner at their intersections in the fabric and prevented from sliding against each other. This ensures the initial pore size / porosity determined by the manufacturing process. After compression, delivery through a catheter and re-release of the implant in a vessel, a materially fitting connection is also provided and remains in place even when side branch flow passes through the fabric.

[0050] In addition to the pores formed by electrospinning, the fabric can be at least partially perforated with further pores, which are formed in the electrospun fabric by processing the fabric, in particular by laser cutting. Thus, after the electrospinning process, an increase in porosity or an increase in pores is achieved in a targeted (and if desired) manner. For example, laser-cut defined pores can be formed over the entire circumference or only on a portion thereof.

[0051] Preferably, the fabric is perforated with additional pores over at least 25%, in particular at least 40%, in particular at least 50% of the circumference of the mesh structure (10). Thus, for example, the area opposite the neck of an aneurysm can be perforated in a targeted manner.

[0052] The fabric may be free of additional pores at least 25%, in particular at least 40%, in particular at least 50% of the circumference of the grid structure. In other words, a portion of the fabric has not been post-treated or subsequently perforated. In this portion of the fabric, no additional pores are introduced into the fabric except for the pores formed by electrospinning. In this area, the fabric consists only of pores formed by electrospinning. In the implanted state, the area of ​​the fabric that is configured without additional pores can be arranged in the area of ​​the neck of the aneurysm. This may be desirable, for example, if the porosity of the electrospun fabric remains unchanged, which is beneficial for the treatment of aneurysms.

[0053] Combinations of regions consisting of unaltered electrospun fabric and regions consisting of subsequently perforated electrospun fabric are feasible.

[0054] Further pores may be formed in both axial directions starting from the axial center of the mesh structure.In another embodiment, additional pores may be arranged at the proximal side or the distal side within the covering or fabric.

[0055] The further apertures may be arranged distributed over a length corresponding to at least 25% of the axial length of the covering or fabric, in particular at least 30%, in particular at least 40%, in particular at least 50% of the axial length of the covering or fabric.

[0056] To facilitate the flow, the size of the further pores may be at least 50 μm, in particular at least 100 μm, in particular at least 200 μm, in particular at least 300 μm.

[0057] The spacing between the other pores can be at least 1 times the spacing, in particular at least 1.5 times the spacing, in particular at least 2 times the spacing, in particular at least 2.5 times the spacing relative to the diameter of the other pores. Therefore, in the case of 1 times the spacing, the spacing is equivalent to the diameter of the other pores.

[0058] If the fabric remains within the inner contour of the lattice structure by at least 0.25 mm, in particular at least 0.5 mm, in particular at least 1 mm when the lattice structure expands, i.e. protrudes as little as possible into the inner cavity of the lattice structure, the formation of wrinkles in the covering or fabric in the blood vessel is limited.

[0059] This is also achieved in that the fabric can extend into the entire inner cavity by a maximum of 10% of the entire inner cavity, in particular by a maximum of 5% of the entire inner cavity, in particular by a maximum of 5% of the entire inner cavity, when the grid structure is expanded.

[0060] In a particularly preferred embodiment, the circumferential contour of the covering is at least partially, in particular completely, marked by a radiopaque medium. This can be achieved, for example, by radiopaque wires, which are woven into a grid structure along the contour of the covering. The contour of the covering can also be obtained by arranging radiopaque sleeves, for example platinum-iridium sleeves or crimped carbon sleeves.

[0061] Thus, under radiographic exposure, the position of the covering or fabric is visible, so that the physician can reliably position the device, even in the correct rotational position.

[0062] The fabric itself may have a radiopaque agent. For example, the threads of the fabric may be filled with a radiopaque material, in particular at least 10% to a maximum of 25% of a radiopaque material, such as barium sulfate BaSO4. The basic color of the threads of the fabric may be transparent, but with the addition of barium sulfate BaSO4 they may appear white / yellow.

[0063] The present invention also includes a medical kit for treating aneurysms, comprising: a main catheter; a medical device according to the present invention, which can be moved through the main catheter to a treatment position to cover the aneurysm, wherein the device is connected or connectable to a delivery wire, wherein the grid structure of the device includes ribs that are connected to each other as a whole and define internal cells and edge cells, wherein the edge cells form closed edge cell rings at the longitudinal ends of the grid structure, and the edge cell rings are connected to the internal cells only on one side, wherein at least one internal cell of the grid structure is at least partially, in particular mostly, free of a covering.

[0064] A parallel aspect of the present invention relates to a method for manufacturing a medical device for introduction into a hollow body organ. In particular, a method for manufacturing a medical device having the above-mentioned features is disclosed and claimed within the scope of the present application. In general, the method according to the present invention comprises the following steps:

[0065] a. Providing a compressible and expandable grid structure, the grid structure consisting of grid elements, which define closed cells of the grid structure, wherein each closed cell is defined by four grid elements;

[0066] b. coating the grid structure with an adhesion promoter, in particular polyurethane; and

[0067] c. Applying the covering to the mesh structure via an electrospinning process.

[0068] In the method according to the invention, the covering is directly built on the grid structure. In order to achieve a firm connection between the grid structure and the covering, an adhesion promoter is used, which is preferably formed of a biocompatible plastic. The adhesion promoter acts as an adhesive and firmly connects the covering to the grid structure. Here, polyurethane has proven to be particularly advantageous as an adhesion promoter.

[0069] It is preferably provided that the grid structure is coated with the adhesion promoter by means of a dip coating process. This process can be carried out particularly simply and quickly and is characterized by a high degree of process safety. For this purpose, the grid structure is dipped into a container filled with the adhesion promoter so that the adhesion promoter adheres to the grid elements of the grid structure. The cells of the grid structure usually do not contain the adhesion promoter, i.e. are not enclosed by the adhesion promoter.

[0070] In a preferred variant of the method according to the invention, a particularly effective fixation of the covering on the grid structure is achieved by providing the adhesion promoter and the covering with respective plastic materials. The two plastics of the adhesion promoter and the covering are easily connected to each other and thus firmly joined to the grid structure. It is particularly effective if, as proposed in the preferred variant, the plastic materials come from the same material group. In particular, both the adhesion promoter and the covering can be formed from polyurethane. In particular, it can be proposed that the adhesion promoter, which is preferably applied to the grid structure by a dip coating process, adheres to the grid structure in a substantially form-fitting manner. The covering is then connected to the adhesion promoter in a material-fitting manner due to the plastic material of the material group. In summary, a firm connection is thus established between the grid structure and the covering.

[0071] Furthermore, the application of the covering to the grid structure by the electrospinning process can be followed by a laser cutting process. In particular, the pores of the covering can be post-processed by means of laser cutting. In particular, it is conceivable to individually adapt the pore shape and / or pore size by means of the laser cutting process. For example, the pore size of individual pores can be increased in a targeted manner.

[0072] Furthermore, the covering can be structured as a whole, in particular by means of a laser cutting process. Preferably, this structuring is carried out at the longitudinal ends of the grid structure. For example, the covering can be structured in such a way that it follows the grid elements at the longitudinal ends of the grid structure. It is also possible to introduce openings in the central region of the covering or the grid structure, in particular by means of laser cutting, in order to enable blood to flow into branch vessels, for example.

[0073] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings. In the accompanying drawings:

[0074] Figure 1 shows a side view of a medical device according to the present invention according to a preferred embodiment;

[0075] Figure 2 shows a scanning electron microscope photograph of a covering of a medical device according to the present invention according to a preferred embodiment;

[0076] Figure 3 shows a scanning electron microscope photograph of a covering of a medical device according to the present invention according to another embodiment;

[0077] Figure 4 A perspective view showing a lattice structure of a medical device according to the present invention according to another preferred embodiment;

[0078] Figure 5 shows a scanning electron microscope photograph of a covering of a medical device according to the present invention according to another embodiment magnified 500 times;

[0079] Figure 6 Shown is a 3500-fold magnification of Figure 5 Scanning electron micrograph of the covering;

[0080] Figure 7 A schematic diagram showing a medical device according to the present invention according to another preferred embodiment, wherein a partially applied fabric is in an implanted state; and

[0081] Figure 8 A schematic diagram of a medical device according to the invention is shown according to another preferred embodiment, wherein the partially perforated fabric is in an implanted state.

[0082] The accompanying drawings show a medical device suitable for introduction into a hollow body organ. In particular, the medical device has a compressible and expandable mesh structure 10. In other words, the mesh structure 10 can adopt a delivery state in which the mesh structure 10 has a relatively small cross-sectional diameter. Preferably, the mesh structure 10 is self-expandable, so that the mesh structure 10 automatically expands to a maximum cross-sectional diameter without the influence of external forces. The state in which the mesh structure 10 has a maximum cross-sectional diameter corresponds to the expanded state. In this state, the mesh structure 10 does not exert any radial force.

[0083] Preferably, the grid structure 10 is constructed in one piece. In particular, the grid structure 10 can be constructed at least partially cylindrical. Preferably, the grid structure 10 is made from a tubular blank by laser cutting. Here, the individual grid elements or ribs 11, 12, 13, 14 of the grid structure 10 are exposed by laser cutting. The area removed from the blank forms the unit 30 of the grid structure 10.

[0084] The units 30 have a substantially rhombus-shaped basic shape. In particular, the units 30 are each defined by four ribs 11, 12, 13, 14. In the embodiment shown, the ribs 11, 12, 13, 14 have at least partially a curved, in particular S-shaped, course. The ribs may also have other shapes.

[0085] The cells 30 have cell tips 31, 32, which determine the corner points of the rhombus basic shape. The cell tips 31, 32 are arranged on the rib beam connectors 20, which connect the four rib beams 11, 12, 13, 14 to each other. Four rib beams 11, 12, 13, 14 start from each rib beam connector 20, wherein each rib beam 11, 12, 13, 14 is associated with two cells 30. The rib beams 11, 12, 13, 14 define the cells 30.

[0086] Figure 1The lattice structure 10 is shown in an expanded state. It can be clearly seen that the rib-beam connections 20 are arranged substantially on a common circumferential line. Thus, in general, a plurality of cells 30 in the circumferential direction of the lattice structure 10 form a cell ring 34. A plurality of cell rings 34 connected to each other in the longitudinal direction form the entire lattice structure 10. In the embodiment shown, these cell rings 34 each include six cells 30.

[0087] In this context, it should be noted that the mesh structure 10 can only partially consist of interconnected unit rings having the same cross-sectional diameter. Conversely, the mesh structure 10 can also partially have a geometric shape different from a cylindrical shape. For example, the mesh structure can be configured as a funnel at least at the proximal end. This configuration is useful for use as a thrombus catcher. Or generally used as a thrombectomy device in medical devices. In this type of case, the mesh structure 10 can basically form a basket-like structure.

[0088] The completely cylindrically configured lattice structure 10 is used in particular in medical devices forming stents. Stents can be used to support blood vessels or in general to support hollow body organs and / or to cover aneurysms.

[0089] When the mesh structure 10 is discharged from the catheter or a general delivery system, the mesh structure 10 automatically expands radially. Here, the mesh structure 10 undergoes multiple expansion levels until the mesh structure 10 reaches an implanted state. In the implanted state, the mesh structure 10 preferably applies radial forces to the surrounding blood vessel wall. In the implanted state, the mesh structure 10 preferably has a cross-sectional diameter that is about 10%-30%, in particular about 20%, smaller than the cross-sectional diameter of the mesh structure 10 in the expanded state. The implanted state is also referred to as the "intended use configuration".

[0090] from Figure 1 As can be clearly seen in FIG. 1 , a radiographic marker 50 is provided in the medical device. The radiographic marker 50 is arranged at the cell tips 31, 32 of the cells 30 at the edge of the grid structure 10. Specifically, the radiographic marker 50 can be configured as a radiopaque sleeve, for example a sleeve made of platinum or gold, which is crimped onto the cell tips 31, 32 of the cells 30 at the edge. Figure 1 It can be seen in FIG. 1 that three radiation markers 50 are arranged at each longitudinal end of the grid structure 10 .

[0091] according to Figure 1The grid structure 10 can be divided into three parts. Two edge parts, each formed by two unit rings 34, are connected by a middle part including five unit rings 34. The units 30 of the middle part have a substantially rhombus-shaped geometry, wherein all the ribs 11, 12, 13, 14 of the units 30 of the middle part have substantially the same length. The unit rings 34 of the edge sides respectively include units 30 in which two ribs 11, 12, 13, 14 directly adjacent in the circumferential direction are respectively formed longer than the ribs 11, 12, 13, 14 of the same unit 30 adjacent in the axial direction. In this respect, the units 30 of the edge sides essentially form a kite-shaped basic shape.

[0092] according to Figure 1 The medical device also includes a cover 40, which is arranged on the outer side of the grid structure 10. The cover 40 spans the entire grid structure 10 and in particular covers the cells 30. The cover 40 is formed by an electrospun fabric and is therefore characterized by a particularly thin wall thickness. At the same time, the cover 40 is stable enough to follow the expansion of the grid structure 10. Preferably, the cover 40 is completely and firmly connected to the grid structure 10. Specifically, the cover 40 is preferably bonded to the ribs 11, 12, 13, 14, for example, by an adhesion promoter, which is applied to the grid structure 10 by a dip coating method.

[0093] like Figure 1 As shown, the covering 40 can extend over the entire mesh structure 10. Alternatively, the covering 40 can span only a portion of the mesh structure 10. For example, the edge cells on one axial end or both axial ends of the mesh structure 10 may have no covering. In this regard, the covering 40 may terminate before the last or second to last cell ring 34 of the mesh structure 10. The cell ring 34 without a covering enables good connection with the delivery wire. In addition to this, the edge cells hardly participate in the coverage of the aneurysm, but are intended to be anchored in the blood vessel, in such a way that high permeability is achieved, so that the inner wall of the blood vessel in this area is well supplied with nutrients. The area of ​​the medical device with the covering 40 can be characterized by a radiographic marker.

[0094] The design of the cover 40 is based on Figure 2 and Figure 3 It is clearly visible in the scanning electron microscope photo of the . It can be seen that the cover 40 has a plurality of pores 41 of irregular size, which are defined by wires 42 respectively. A plurality of wires 42 that are irregularly oriented to each other are formed by the electrospinning process. Here, the pores 41 are formed. Figure 2 It can also be seen that the pores 41 have a relatively small pore size, but some of the pores 41 are large enough to ensure blood permeability. Specifically, Figure 2The graphic highlights the size of the 2 Four pores 41. Size greater than 30 μm 2 The density of pores 41 indicates that the covering is 100,000 μm 2 There are at least 10 such pores 41 over an area of ​​.

[0095] Figure 3 Another embodiment of a cover 40 is shown, in which a generally larger pore size is provided. It can be seen that some pores 41 have a diameter greater than 30 μm. 2 The size of the pores does not exceed 300 μm. 2 .

[0096] The flow of the covered side branch (blood vessel) may be significantly affected by the duration of opening during establishment. For example, a stent opened for 1 minute causes the side branch flow to be reduced by about 10%-40%. For example, a stent opened for 2 minutes causes the side branch flow to be reduced by about 40%-70%. For example, a stent opened for 4 minutes causes the side branch flow to be reduced by about 70%-95%. When the fabric is applied to the mesh structure 10 by electrospinning, the longer the spinning process lasts, the denser the fabric becomes and the smaller the pores. As a result, the flow of the side branch (blood vessel) can be affected in a targeted manner.

[0097] exist Figure 2 and Figure 3 , respectively, that the threads 42 of the cover 40 cross many times. However, a special feature of the electrospinning method is that there are only two (i.e. no more than two) points where the threads 42 cross in the cover 40. It can be seen from this that the cover 40 has a very thin wall thickness as a whole and is therefore highly flexible.

[0098] The high flexibility of the covering 40 combined with the high flexibility of the mesh structure 10 makes it possible to provide a medical device (particularly a stent) that can be introduced into a blood vessel through a very small delivery catheter. In particular, delivery catheters of a size of 6 French, particularly a maximum of 5 French, particularly a maximum of 4 French, particularly a maximum of 3 French, particularly a maximum of 2 French can be used. In particular, the medical device according to the embodiments described herein can be used in catheters having an inner diameter of a maximum of 1.6 mm, particularly a maximum of 1.0 mm, particularly a maximum of 0.7 mm, particularly a maximum of 0.4 mm.

[0099] In a particularly preferred variant, the layer thickness of the cover 40 is a maximum of 10 μm, in particular a maximum of 8 μm, in particular a maximum of 6 μm, in particular a maximum of 4 μm. In this case, a maximum of 4, in particular a maximum of 3, in particular a maximum of 2 threads 42 cross. In general, the crossing points are arranged in the electrospun structure of the cover 40, in which only 2 threads 42 cross. Preferably, the cross-sectional diameter of the mesh structure 10 is between 2.5 mm and 8 mm, in particular between 4.5 mm and 6 mm.

[0100] Figure 4 A braided mesh structure 10 is shown which in a preferred embodiment may form a carrier for a covering 40. The braided mesh structure 10 is formed from individual wires 16 that are braided into a tubular shape. The wire ends are connected within the mesh structure 10 to connecting elements 18.

[0101] The wire 16 has a plurality of sections, which are referred to as mesh elements 11, 12, 13, 14. Each section of the wire 16 extending between two intersections 19 is referred to as an individual mesh element 11, 12, 13, 14. It can be seen that every four mesh elements 11, 12, 13, 14 define a cell or unit 30.

[0102] The braided mesh structure 10 has expanded axial ends, which are called flared portions 17. In each flared portion 17, the wire 16 is bent and forms a terminal loop 15. In general, in the embodiment shown, six terminal loops 15 are provided at each flared portion 17. Every two terminal loops 15 carry a radiation marker 50 in the form of a crimped sleeve. Therefore, there are three radiation markers 50 at each axial end of the mesh structure 10.

[0103] exist Figure 5 and Figure 6 , an embodiment of a device according to the invention is shown in different magnifications of scanning electron microscope photographs. The device comprises a Figure 4 The invention relates to a mesh structure 10, which is formed with a cover 40 made of an electrostatically spun fabric. The cover 40 is arranged on the outer side of the tubular mesh structure 10.

[0104] Figure 5 A 500-fold magnification of a region of the device including the cell tip 32 of the grid structure 10 is shown. The two grid elements or ribs 11, 13 of the cell 30 meet at the cell tip 32. A cover 40 covers the ribs 11, 12. It can be seen that the cover 40 has a plurality of pores 41 of different sizes, i.e. completely open through openings. The porosity is set in this case so that the cover 40 forms a good barrier to flow through, but at the same time allows nutrients to pass through.

[0105] according to Figure 6 The 3500 times magnified image shows in detail the Figure 5 A portion of a cover 40 of an electrospun fabric. The direction of the individual threads 42 of the electrospun fabric is clearly visible. The threads 42 define pores 41, wherein the pores 41 are irregularly formed. In any case, it can be seen that some pores 41 have a larger passage surface than other pores 41. The larger pores 41 allow nutrients to pass through the cover 40.

[0106] Figure 7 A mesh structure 10 according to an embodiment of the invention (stent) is shown in an implanted state, wherein a covering 40 is arranged on the mesh structure 10 in the region of the aneurysm neck and covers it. The covering 40 is arranged on a partial circumference or an angular segment of the mesh structure 10. In this example, the fabric or covering 40 covers approximately half of the circumference of the mesh structure 10 or stent. Different degrees of coverage, i.e. more or less than half of the circumference of the mesh structure 10 are possible. Figure 7 It can be seen that Figure 8 Unlike the pores formed by electrospinning, no additional pores are provided in the fabric. Therefore, the properties of the fabric are determined solely by the pores formed during the manufacturing process by electrospinning.

[0107] Figure 8 Another embodiment of the present invention is shown, wherein implantation of Figure 7 The mesh structure 10 is shown for use in treating aneurysms. Figure 7 In contrast, the covering 40, in particular a fabric, is applied completely to the mesh structure 10, in particular by electrospinning. A portion of the covering 40, in particular the portion of the covering 40 opposite the neck of the aneurysm, is perforated in addition to the pores formed during electrospinning. This is achieved by post-processing the fabric, for example by laser cutting. The additional pores 43 thus formed in the fabric are larger than the pores formed by electrospinning, such as Figure 8 As shown. Figure 8 In the example of , four additional pores 43 are formed per unit. The number of additional pores 43 can vary. Unlike the pores formed by electrospinning, the additional pores 43 are geometrically defined, for example circular. This can be achieved by laser cutting.

[0108] Additional perforations of the fabric can have a targeted influence on the permeability of the fabric, for example to improve the blood supply in the side branches, without affecting the treatment of the aneurysm.

[0109] Reference Mark List

[0110] 10 Grid structure

[0111] 11, 12, 13, 14 Beam or mesh element

[0112] 15 Terminal Loopback

[0113] 16 Wire

[0114] 17 Flared part

[0115] 18 Connecting elements

[0116] 19 Intersection

[0117] 20 Beam connector

[0118] 30 units

[0119] 31, 32 unit tip

[0120] 34 unit ring

[0121] 40 Cover

[0122] 41 Porosity

[0123] 42 Silk Thread

[0124] 43 Additional pores

[0125] 50 radiographic markers.

Claims

1. A medical device for introduction into a hollow body organ, comprising a compressible and expandable mesh structure (10) consisting of mesh elements (11, 12, 13, 14), the mesh structure having at least one closed cell ring (34), the cell ring comprising at most 12 cells (30) directly adjacent in the circumferential direction of the mesh structure (10), It is characterized in that The mesh structure (10) is at least partially provided with a covering (40) made of an electrospun fabric having pores (41) of irregular size, wherein the covering (40) has a diameter of 100,000 μm. 2 The area includes a size of at least 15 μm 2 at least 10 pores (41).

2. The medical device according to claim 1, characterized in that The unit ring includes at most 10 units (30) that are directly adjacent to each other in the circumferential direction of the grid structure (10).

3. The medical device according to claim 1, characterized in that The unit ring includes at most eight units (30) that are directly adjacent to each other in the circumferential direction of the grid structure (10).

4. The medical device according to claim 1, characterized in that The unit ring includes at most 6 units (30) directly adjacent to each other in the circumferential direction of the grid structure (10).

5. The medical device according to any one of claims 1 to 4, characterized in that: The cover (40) has a thickness of 100,000 μm. 2 The area includes a size of at least 30 μm 2 at least 10 pores (41).

6. The medical device according to any one of claims 1 to 5, characterized in that: The inscribed circle diameter of the at least 10 pores (41) is at least 4 μm.

7. The medical device according to claim 6, characterized in that The inscribed circle diameter of the at least 10 pores (41) is at least 5 μm.

8. The medical device according to claim 6, characterized in that The inscribed circle diameter of the at least 10 pores (41) is at least 6 μm.

9. The medical device according to claim 6, characterized in that: The inscribed circle diameter of the at least 10 pores (41) is at least 7 μm.

10. The medical device according to claim 6, characterized in that The inscribed circle diameter of the at least 10 pores (41) is at least 8 μm.

11. The medical device according to claim 6, characterized in that: The inscribed circle diameter of the at least 10 pores (41) is at least 9 μm.

12. The medical device according to claim 6, characterized in that The inscribed circle diameter of the at least 10 pores (41) is at least 10 μm.

13. The medical device according to claim 6, characterized in that The inscribed circle diameter of the at least 10 pores (41) is at least 12 μm.

14. The medical device according to claim 6, characterized in that The inscribed circle diameter of the at least 10 pores (41) is at least 15 μm.

15. The medical device according to claim 6, characterized in that The inscribed circle diameter of the at least 10 pores (41) is at least 20 μm.

16. The medical device according to any one of claims 1 to 15, characterized in that: The grid elements (11, 12, 13, 14) define closed cells (30) of the grid structure (10), wherein each closed cell (30) is defined by four grid elements (11, 12, 13, 14).

17. The medical device according to any one of claims 1 to 16, characterized in that: The cover (40) has a thickness of 100,000 μm. 2 The area includes a size of at least 30 μm 2 at least 15 pores (41).

18. The medical device according to claim 17, characterized in that The cover (40) has a thickness of 100,000 μm. 2 The area includes a size of at least 50 μm 2 at least 15 pores (41).

19. The medical device according to claim 17, characterized in that The cover (40) has a thickness of 100,000 μm. 2 The area includes a size of at least 70 μm 2 at least 15 pores (41).

20. The medical device according to claim 17, characterized in that The cover (40) has a thickness of 100,000 μm. 2 The area includes a size of at least 90 μm 2 at least 15 pores (41).

21. The medical device according to any one of claims 1 to 16, characterized in that: The cover (40) has a thickness of 100,000 μm. 2 The area includes a size of at least 30 μm 2 at least 20 pores (41).

22. The medical device according to claim 21, characterized in that The cover (40) has a thickness of 100,000 μm. 2 The area includes a size of at least 30 μm 2 at least 25 pores (41).

23. The medical device according to any one of claims 1 to 22, characterized in that The size of the pores (41) is a maximum of 750 μm 2 .

24. The medical device according to claim 23, characterized in that The size of the pores (41) is a maximum of 500 μm 2 .

25. The medical device according to claim 23, characterized in that The size of the pores (41) is at most 300 μm 2 .

26. The medical device according to any one of claims 1 to 25, characterized in that The covering (40) is firmly connected to the grid structure (10).

27. The medical device according to claim 26, characterized in that The covering (40) is connected to the grid structure (10) in a material-fitting manner.

28. The medical device according to any one of claims 1 to 27, characterized in that The grid elements (11, 12, 13, 14) are coated with an adhesion promoter.

29. The medical device according to claim 27, characterized in that The grid elements (11, 12, 13, 14) are coated with an adhesion promoter which forms a material-bonded connection between the cover (40) and the grid structure (10).

30. The medical device according to claim 28 or 29, characterized in that The adhesion promoter is polyurethane.

31. The medical device according to any one of claims 1 to 30, characterized in that The grid structure (10) at least partially forms a cylindrical and / or funnel-shaped hollow body.

32. The medical device according to claim 31, characterized in that The hollow body can be completely flowed through in the direction of the longitudinal axis.

33. The medical device according to any one of claims 1 to 32, characterized in that The cover (40) is arranged on the outer side of the grid structure (10).

34. The medical device according to claim 31 or 32, characterized in that The cover (40) is arranged on the outer side of the hollow body.

35. The medical device according to any one of claims 1 to 34, characterized in that The cover (40) is formed of a plastic material.

36. The medical device according to claim 35, characterized in that The cover (40) is formed of polyurethane.

37. The medical device according to any one of claims 1 to 36, characterized in that The covering (40) is formed of wires (42) arranged irregularly in a mesh shape, the wire thickness of the wires being between 0.1 μm and 3 μm.

38. The medical device according to claim 37, characterized in that The thread thickness of the thread is between 0.2 μm and 2 μm.

39. The medical device according to claim 37, characterized in that The thread thickness of the thread is between 0.5 μm and 1.5 μm.

40. The medical device according to claim 37, characterized in that The thread thickness of the thread is between 0.8 μm and 1.2 μm.

41. The medical device according to any one of claims 1 to 40, characterized in that The medical device is a stent.

42. The medical device according to any one of claims 1 to 41, characterized in that The medical device is a stent for treating an aneurysm in an arterial blood vessel.

43. The medical device according to any one of claims 1 to 41, characterized in that The medical device is a stent for treating aneurysms in a neurovascular vessel.

44. The medical device according to any one of claims 1 to 43, characterized in that At least 60% of the area of ​​the cover (40) is composed of 2 The pores (41) are formed.

45. The medical device according to claim 44, characterized in that At least 70% of the area of ​​the cover (40) is composed of 2 The pores (41) are formed.

46. ​​The medical device according to claim 44, characterized in that At least 80% of the area of ​​the cover (40) is composed of 2 The pores (41) are formed.

47. The medical device according to any one of claims 1 to 46, characterized in that At least 30% of the area of ​​the cover (40) is composed of a material having a size of at least 30 μm 2 The pores (41) are formed.

48. The medical device according to any one of claims 1 to 47, characterized in that At most 20% of the area of ​​the cover (40) consists of particles having a size of at least 500 μm 2 The pores (41) are formed.

49. The medical device according to any one of claims 1 to 48, characterized in that At most 50% of the area of ​​the cover (40) is composed of particles having a size of at least 300 μm 2 The pores (41) are formed.

50. The medical device according to any one of claims 1 to 49, characterized in that The grid elements (11, 12, 13, 14) form ribs or interwoven wires connected to each other as one body through rib connectors (20).

51. The medical device according to any one of claims 1 to 50, characterized in that The elongation of the cover (40) according to ASTM 412 is between 300% and 550%.

52. The medical device according to claim 51, characterized in that The elongation of the cover (40) according to ASTM 412 is between 350% and 500%.

53. The medical device according to claim 51, characterized in that The elongation of the cover (40) according to ASTM 412 is between 375% and 450%.

54. The medical device according to any one of claims 1 to 53, characterized in that The elastic modulus of the cover (40) according to ASTM 412 is as follows: When the elongation is 50%: >15-21MPa(psi); When the elongation is 100%: >18<26MPa(psi); When the elongation is 300%: >32<41MPa(psi).

55. The medical device according to any one of claims 1 to 54, characterized in that The cover (40) has a Shore hardness according to ASTM D 2240 between 80A and 85D.

56. The medical device according to any one of claims 1 to 54, characterized in that The cover (40) has a Shore hardness of between 90A and 80D according to ASTM D 2240.

57. The medical device according to any one of claims 1 to 54, characterized in that The cover (40) has a Shore hardness of between 55D and 75D according to ASTM D 2240.

58. The medical device according to any one of claims 1 to 57, characterized in that The covering (40) is capable of returning to its original configuration after compression and re-release of the lattice structure (10).

59. The medical device according to any one of claims 1 to 57, characterized in that The covering (40) is capable of returning to its unfolded configuration following compression and re-release of the lattice structure (10).

60. The medical device according to any one of claims 1 to 59, characterized in that The threads of the fabric are connected to one another in a materially bonded manner at the crossing points in the fabric.

61. The medical device according to any one of claims 1 to 60, characterized in that In addition to the pores formed by electrospinning, the fabric is at least partially perforated by further pores which are formed in the electrospun fabric by processing the fabric.

62. The medical device according to claim 61, characterized in that The additional pores are formed in the electrospun fabric by laser cutting.

63. The medical device according to claim 61 or 62, characterized in that The fabric is perforated with the further apertures over at least 25% of the circumference of the grid structure (10).

64. The medical device according to claim 63, characterized in that The fabric is perforated with the further apertures over at least 40% of the circumference of the grid structure (10).

65. The medical device according to claim 63, characterized in that The fabric is perforated with the further apertures over at least 50% of the circumference of the grid structure (10).

66. The medical device according to any one of claims 61-65, characterized in that The fabric has no additional pores over at least 25% of the circumference of the grid structure (10).

67. The medical device according to claim 66, characterized in that The fabric has no additional pores over at least 40% of the circumference of the grid structure (10).

68. The medical device according to claim 66, characterized in that The fabric has no additional pores over at least 50% of the circumference of the grid structure (10).

69. The medical device according to any one of claims 61-68, characterized in that The additional pores are formed in two axial directions starting from the axial center of the grid structure (10).

70. The medical device according to any one of claims 61-69, characterized in that The further pores have a size of at least 50 μm.

71. The medical device according to claim 70, characterized in that The further pores have a size of at least 100 μm.

72. The medical device according to claim 70, characterized in that The further pores have a size of at least 200 μm.

73. The medical device according to claim 70, characterized in that The further pores have a size of at least 300 μm.

74. The medical device according to any one of claims 61-73, characterized in that The further pores are spaced apart from one another by at least 1 times the diameter of the further pores.

75. The medical device according to claim 74, characterized in that The further pores are spaced apart from one another by at least 1.5 times the diameter of the further pores.

76. The medical device according to claim 74, characterized in that The further pores are spaced apart from one another by at least 2 times the diameter of the further pores.

77. The medical device according to claim 74, characterized in that The further pores are spaced apart from one another by at least 2.5 times the diameter of the further pores.

78. The medical device according to any one of claims 1-77, characterized in that The fabric remains within the inner contour of the mesh structure by at least 0.25 mm when the mesh structure is expanded.

79. The medical device according to claim 78, characterized in that The fabric remains within the inner contour of the mesh structure by at least 0.5 mm when the mesh structure is expanded.

80. The medical device according to claim 78, characterized in that The fabric remains within the inner contour of the mesh structure by at least 1 mm when the mesh structure is expanded.

81. The medical device according to any one of claims 1-80, characterized in that The fabric extends into the entire inner cavity and occupies at most 10% of the entire inner cavity when the grid structure is expanded.

82. The medical device according to claim 81, characterized in that The fabric extends into the entire inner cavity to a maximum of 5% of the entire inner cavity when the mesh structure is expanded.

83. The medical device according to claim 81, characterized in that The fabric extends into the entire inner cavity to a maximum of 2% of the entire inner cavity when the mesh structure is expanded.

84. The medical device according to any one of claims 1 to 83, characterized in that The circumferential contour of the covering (40) is at least partially marked by a radiopaque agent.

85. The medical device according to any one of claims 1-83, characterized in that The circumferential contour of the covering (40) is completely marked by a radiopaque medium.

86. The medical device according to any one of claims 1-85, characterized in that The fabric itself has a radiopaque agent.

87. A medical kit for treating an aneurysm, comprising: a main catheter; a medical device according to any one of claims 1-86, the medical device being capable of being moved through the main catheter to a treatment site for covering the aneurysm, wherein the device is connected or capable of being connected to a delivery wire, wherein the mesh structure (10) of the device comprises ribs (16), the ribs being connected to one another as a whole and defining internal cells (18) and edge cells (20), wherein the edge cells (20) form closed edge cell rings (24) at longitudinal ends (22) of the mesh structure (10), the edge cell rings being connected to the internal cells (18) only on one side, wherein at least one internal cell (18) of the mesh structure (10) is at least partially free of a covering.

88. A method of manufacturing a medical device for introduction into a hollow body organ, the medical device being a medical device according to any one of claims 1 to 86, wherein the method comprises the steps of: a. providing a compressible and expandable grid structure (10), the grid structure consisting of grid elements (11, 12, 13, 14), the grid elements defining closed cells (30) of the grid structure (10), wherein each closed cell (30) is defined by four grid elements (11, 12, 13, 14); b. coating the grid structure (10) with an adhesion promoter; as well as c. Applying a covering (40) to the mesh structure (10) by an electrospinning process.

89. The method according to claim 88, characterized in that The grid structure (10) is coated with the adhesion promoter by a dip coating process.

90. The method according to claim 88 or 89, characterized in that The adhesion promoter and the covering each comprise a plastic material.

91. The method according to claim 88 or 89, characterized in that The adhesion promoter and the covering each comprise a plastic material from the same material group.

92. The method according to claim 88 or 89, characterized in that The adhesion promoter and the covering each comprise polyurethane.

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