Medical implant for treating an aneurysm

Abstract

The invention relates to a medical implant for treating an aneurysm, having a support structure (1) with a compressible and expandable mesh structure (10) composed of mesh elements which define mesh openings, wherein the mesh structure (10) is at least partially covered with a membrane (2) composed of fibers, in particular an electrospun membrane, which comprises at least one intraluminal functional layer (4) and at least one extraluminal support layer (3), the layers having pores, respectively, wherein the porosity of the functional layer (4) is smaller than the porosity of the support layer (3). The invention is characterized in that the membrane (2) is configured such that the pores of at least the functional layer (4) open due to a pressure gradient occurring between the liquid pressure in the internal through passage of the support structure (1) and the liquid pressure outside the support layer (3) to increase the liquid flow through the membrane (2).

Description

[0001] This invention relates to medical implants for treating aneurysms. Such implants are known, for example, from EP 2 678 466 B1.

[0002] EP 2 678 466 B1 relates to a stent for neurovascular applications, the stent being covered with a nonwoven fabric. The nonwoven fabric is manufactured by electrospinning and comprises multiple layers, wherein an inner layer is configured to be impermeable to fluids and an outer layer is configured to be spongy. The inner layer is used to encapsulate the aneurysm, protecting it from blood flow within the vessel. The spongy outer layer should allow for the embedding of endothelial cells and / or drugs. A disadvantage of known implants is that they can only be used for aneurysms located away from branch vessels, arteries, or arterioles. For aneurysms near vascular branches, there is also a risk of isolating the branch vessels from blood flow when using known implants. As a result, significant inadequacy may occur in tissue areas that should be supplied with oxygen and nutrients by the branch vessels.

[0003] In this context, the objective of the present invention is to provide a medical implant for treating aneurysms that, on the one hand, effectively covers the aneurysm, and on the other hand, ensures that the blood supply to the branch vessels is still guaranteed.

[0004] This task is accomplished through the medical implants described below.

[0005] Therefore, the present invention is based on the concept of providing a medical implant for treating aneurysms, the implant having a support structure having a compressible and expandable mesh structure composed of mesh elements defining mesh openings. The mesh structure is at least partially covered by a membrane formed or composed of fibers. The membrane includes at least one intraluminal functional layer and at least one extraluminal support layer, each layer having pores. Here, the porosity of the functional layer is less than the porosity of the support layer. According to the invention, the membrane is configured such that the pores of at least the intraluminal functional layer of the membrane open due to a pressure gradient between the fluid pressure in the internal through-channels of the support structure and the fluid pressure outside the extraluminal support layer, thereby increasing the fluid flow rate through the membrane.

[0006] Therefore, this invention is based on the idea of ​​enabling the membrane to function intelligently, such that the membrane becomes more fluid-permeable when a pressure gradient exists between the fluid pressure in the internal permeable channels of the support structure and the fluid pressure outside the membrane. In the implanted state, when the membrane, inserted with the implant into the main blood vessel, crosses the branch vessels and thus creates a pressure gradient between the main blood vessel (particularly an artery) and the arteries or arterioles branching from the main blood vessel, the pores of the membrane, particularly those in the functional layer, open. Blood flowing into the branch vessels (particularly branch arteries or arterioles) through the main blood vessel has a fluid pressure that forces blood into the branch vessels or arterioles. Therefore, the intima is designed such that this fluid pressure is sufficient to locally open the pores of at least the functional layer of the membrane, such that the membrane becomes blood-permeable at the location where the vessel (particularly an artery or arteriole) branches. In particular, the membrane is adapted to become blood-permeable, thereby ensuring adequate oxygen and nutrients to the tissue regions connected by the branch vessels or arterioles.

[0007] However, in the area where the implant covers the aneurysm, this pressure gradient is absent, so the pores of the membrane remain closed, thereby effectively shielding the aneurysm from intravascular blood flow. In all cases, this shielding is proposed to be more effective than with currently known or conventional flow diverter implants.

[0008] Here, shielding does not necessarily refer to a complete fluid barrier. More precisely, it can greatly reduce fluid exchange between the blood within the aneurysm and the blood within the main blood vessel. However, shielding the aneurysm is sufficient to reduce blood flow within it, causing the blood to clot and form a thrombus within the aneurysm. In this respect, the aneurysm naturally shrinks, with the implanted membrane ensuring that the thrombus does not leave the aneurysm. The formation of the thrombus reduces pressure on the aneurysm wall, thereby reducing the risk of aneurysm rupture and the associated blood loss or hemorrhagic stroke.

[0009] The advantages of the implant according to the invention are obvious. When treating aneurysms (especially cerebral aneurysms) using the implant according to the invention, the surgeon does not necessarily need to precisely determine the implant's location. In particular, the surgeon does not need to carefully insert an implant of a specific length to avoid covering branch vessels. This is especially applicable to smaller branch vessels, namely so-called "perforating arteries" (which typically have a diameter between 300 µm and 850 µm) and branch arterioles (which typically have a diameter between 50 µm and 300 µm). More precisely, standard-length medical implants can be used for any type of aneurysm because even if the implant covers branch vessels (especially arteries and branch arterioles), the implant still allows blood flow into the branch vessels (especially arteries or arterioles). This greatly simplifies and speeds up the treatment of aneurysms.

[0010] Preferably, the membrane comprises an electrowoven fabric formed of fibers. Preferably, the fabric is multilayered and formed of fibers with different properties. In particular, the fabric may include a support layer and a functional layer, each formed of fibers with different properties, particularly different elasticities and / or fiber thicknesses. Preferably, the membrane has a relatively low porosity on the intraluminal side (i.e., the side facing the main vessel lumen), which increases under a pressure gradient (thus forming the actual function), and a relatively high porosity on the extraluminal side (i.e., the side facing the vessel wall), which provides support. In this respect, this application distinguishes between the intraluminal functional layer, which determines the function of the membrane, and the extraluminal support layer, which supports the functional layer. Under the influence of a pressure gradient generated by branch vessels or branch arterioles, the porosity of the support layer remains substantially unchanged or at least almost unchanged. Furthermore, the support layer may be designed to prevent the fibers of the functional layer from shifting in the radial direction.

[0011] Specifically, the functional layer and the support layer can differ depending on the type of fiber arrangement. Preferably, the support layer comprises or is composed of fibers that are primarily cross-linked (vernetzen) with each other, thus forming a stable layer. The degree of freedom of movement of the fibers in the support layer is restricted by the cross-linking. In contrast, the functional layer can be composed of or comprise fibers that are primarily loosely stacked with each other. This allows for greater degree of freedom of movement of the fibers, thus enabling the formation of larger pores through fiber displacement. Preferably, the fibers in the support layer have a relatively large diameter and relatively high strength or Shore hardness, while the fibers in the functional layer can have a relatively small diameter and relatively low strength or Shore hardness.

[0012] In principle, it can be proposed here that the functional layer and the support layer form clearly defined boundaries between each other. However, the functional layer and the support layer may also lack a clear boundary, with these regions of different porosities smoothly merging together. Preferably, the membrane strikes a trade-off between functionality (opening or closing pores through fiber movement or deformation) and support effects. Here, regions of different porosities (particularly the functional layer and the support layer) can be blurred together, making it impossible to distinguish the functional layer and the support layer from each other in the direction of the pressure gradient. More precisely, the membrane as a whole can have almost the same porosity in the direction of the pressure gradient. The above applies to the unloaded state of the membrane, i.e., without the effect of a pressure gradient. Conversely, under the influence of a pressure gradient, some fibers in the functional layer of the membrane will move or deform, thereby forming larger pores and thus making the membrane permeable to blood, allowing branch vessels to deliver sufficient oxygen and nutrients to downstream tissue areas. Deformation can be elastic or plastic. In any case, it is proposed that the formation of larger pores occurs without fiber cracking. More precisely, the enlargement of the pores can occur without damage and can also be reversed without damage, for example, when the pressure gradient between the liquid pressure in the internal through-channels of the support structure and the liquid pressure outside the support layer decreases without damage.

[0013] Preferably, the functional layer and the support layer are connected to each other by material determination. Specifically, the fibers of the functional layer and the support layer may cross above or below, thereby forming a uniform membrane. Preferably, the intraluminal functional layer and the extraluminal support layer differ by their porosity and associated functions. The extraluminal support layer should substantially stabilize the membrane as a whole and hold the fibers of the intraluminal functional layer in their predetermined positions, while the functional layer serves to effectively shield the aneurysm from blood flow. However, simultaneously, the functional layer can be opened to allow blood flow into branch vessels to ensure blood supply to downstream tissue areas.

[0014] Preferably, the membrane comprises a functional layer and a support layer. However, this does not preclude the membrane from having additional layers, such as two or more functional layers and / or two or more support layers and / or other additional layers. Furthermore, the membrane may have a coating, for example, with antithrombotic properties. This coating is configured such that each fiber of the membrane is individually coated.

[0015] To ensure the permeability of the functional layer at the location where the blood vessel branches into the main blood vessel from which the implant is inserted, a preferred variant of the invention proposes that the fibers of the membrane, particularly at least the fibers of the functional layer, are loosely arranged relative to each other at the intersections, allowing the crossing fibers at these intersections to move relative to each other. In other words, the crossing fibers of the intima can slide relative to each other, thereby enabling the pores defined by the fibers to open due to the pressure gradient explained above. Thus, a flow region can be created through which blood can be guided into the branch vessels.

[0016] Alternatively or additionally, the fibers of the membrane, particularly at least the fibers of the functional layer, may be elastically deformable and / or plastically deformable so that the fibers are displaced due to pressure gradients and form enlarged pores, thereby locally achieving sufficient blood flow into branch vessels, particularly arteries or branch arterioles, for blood supply to downstream tissue areas.

[0017] To achieve the advantageous function according to the invention, namely that the intracavitary functional layer can be opened segmentally or partially to allow blood or fluid passage, it is advantageous for the functional layer to have high flexibility. In particular, the fibers of the functional layer should be as flexible as possible to allow deformation that results in increased pore size. This pore enlargement preferably occurs without damage or the formation of fiber cracks. In this regard, it is preferred that the fibers of the functional layer have a particularly low fiber thickness. Specifically, the fiber thickness can be less than 500 nm, particularly a maximum of 400 nm, particularly a maximum of 300 nm, particularly a maximum of 200 nm, particularly a maximum of 100 nm. In contrast, the extracavitary support layer with stabilizing function should comprise more stable fibers. This can be achieved by ensuring that the fiber thickness of the support layer is at least 500 nm, particularly at least 750 nm, particularly at least 1000 nm, particularly at least 1250 nm, particularly at least 1500 nm.

[0018] The optimal design of the medical implant also contributes to the function of the functional layer (i.e., releasing blood flow into the branch vessels while still effectively shielding the aneurysm from the influence of blood flow in the main vessel), wherein the thickness of the functional layer is at most 10 µm, particularly less than 10 µm, particularly at most 8 µm, particularly at most 6 µm, particularly at most 4 µm, particularly at most 2 µm. Correspondingly, the thickness of the supporting layer is at least 3 µm, particularly at least 5 µm, particularly at least 6 µm, particularly at least 7 µm, particularly at least 8 µm, which contributes to the stable function of the supporting layer.

[0019] To effectively shield aneurysms, a particularly low porosity of the functional layer is advantageous. In this regard, a preferred variant of the invention proposes that the porosity of the functional layer is less than 50%, particularly a maximum of 40%, and particularly a maximum of 30%. In contrast, the porosity of the support layer, which should have permanent blood permeability, is at least 50%, particularly at least 60%, particularly at least 70%, particularly at least 80%, and particularly at least 90%. Within the scope of this application, porosity is understood as the ratio between the open area of ​​the fabric (i.e., the sum of the areas of all pores) and the total area of ​​the fabric.

[0020] Particularly preferred are variations of medical implants, wherein the functional layer is 100,000 µm 2 The area includes at least 10 holes, the inscribed circle diameter of which is at most 10 µm, particularly at most 8 µm, particularly at most 6 µm, particularly at most 4 µm, particularly at most 2 µm, and particularly at most 1 µm. Alternatively or additionally, the support layer is 100,000 µm. 2 The area may include at least 5 holes, particularly at least 10 holes, the diameter of the inscribed circle of the hole being at least 10 µm, particularly greater than 10 µm, particularly at least 15 µm, particularly at least 20 µm, particularly at least 25 µm, particularly at least 30 µm, particularly at least 40 µm, particularly at least 50 µm, particularly at least 60 µm.

[0021] Regarding the different functions of the functional layer and the support layer, the functional layer should have the flexibility to allow blood to flow under the corresponding pressure gradient, while the support layer should stabilize the functional layer so that it does not detach from the support structure. It is advantageous for the fibers of the functional layer to have a smaller fiber thickness than the fibers of the support layer.

[0022] In this respect, it is also preferable that the functional layer or its fibers have higher ductility than the support layer or its fibers.

[0023] The fibers of the functional layer can be formed of a material having a lower Shore hardness than the material of the fibers of the support layer. In particular, the Shore hardness of the fiber material of the functional layer can be a maximum of 90A, particularly a maximum of 80A, particularly a maximum of 70A, particularly a maximum of 60A, particularly a maximum of 50A, and / or the Shore hardness of the fiber material of the support layer can be at least 90A, particularly at least 100A, particularly at least 60D, particularly at least 70D, particularly at least 80D.

[0024] The membrane, particularly the functional layer and support layer, can be made of thermoplastic polyurethane. This does not preclude the functional layer and / or support layer from comprising other plastic materials, respectively. However, in a preferred variation, it is proposed that the functional layer and support layer be formed of thermoplastic polyurethane. The functional layer or support layer, particularly the functional layer and support layer, or the entire membrane, can also be formed of absorbable or reabsorbable materials. In this regard, it can be proposed that the functional layer and / or support layer dissolve due to contact with blood over a certain period of time, so that after that period, only the supporting structure remains in the blood vessel. Preferably, the absorbable or reabsorbable material is selected or adapted such that it dissolves after or during the period of aneurysm shrinkage shielded by the functional layer. In other words, the functional layer and / or support layer should not dissolve before the aneurysm shrinks.

[0025] The fibers of the functional layer can also be formed as concentric fibers. Such concentric fibers comprise a fiber core and a fiber outer layer. The fiber core is preferably formed of a material softer than the fiber outer layer, wherein the thickness of the fiber outer layer is smaller than that of the fiber core. The fiber outer layer can have a relatively stiff material. In this way, high flexibility of the individual fibers can be achieved through the fiber core, allowing the fibers to easily deform to open pores due to the pressure gradient acting on the membrane. In this respect, the Shore hardness of the fiber core material can be at most 90 A, particularly at most 80 A, particularly at most 70 A, particularly at most 60 A, particularly at most 50 A, and / or the Shore hardness of the fiber outer layer material can be greater than 90 A, particularly at least 100 A, particularly at least 60 D, particularly at least 70 D, particularly at least 80 D. In contrast, the relatively stiff material of the fiber outer layer is used to achieve good sliding between the fibers, thereby also achieving good pore enlargement through fiber displacement.

[0026] In a preferred variant of the invention, the membrane may extend completely around the periphery (Umfang) of the support structure. While it is also conceivable that the membrane may extend only partially around the periphery of the support structure, for example, to allow blood to flow from the supply vessel into the two branch vessels in the case of a bifurcation aneurysm, the preferred variant in which the membrane extends completely around the periphery of the support structure has particular advantages. On the one hand, the manufacture of medical implants with this variant is particularly easy in mass production. On the other hand, the circumferentially closed membrane itself is stable, thus ensuring that the membrane adheres to the support structure and does not detach from it. In particular, the support structure can perform its stabilizing function particularly effectively.

[0027] Regarding the support structure, different variations can be envisioned. On one hand, the support structure can be formed monolithically, where the mesh elements of the grid structure form connecting strips that define the mesh structure as the openings of the cells. In other words, the support structure can have a mesh structure cut from a tubular initial material. This can be achieved, for example, by laser cutting. Connecting strips are created by cutting the tubular initial material, and these connecting strips define the cells. On the other hand, the support structure can also have interwoven wires, where the wires form the mesh cells of the grid structure and define the mesh structure as the openings of the mesh. Thus, in this variation, the support structure has a braid composed of interwoven wires that form the mesh structure. Here, the wires cross each other above and below, where meshes are formed between the crossing wires. The support structure can also include or be formed from non-crossing wire elements. More precisely, the wire elements can be arranged on a common circumferential plane and connected to each other, for example, by welding points. Monolithic designs of support structures can also be fabricated through a combination of photolithography and sputtering methods (e.g., physical vapor deposition, PVD), particularly through magnetron sputtering.

[0028] Advantageous for the application of the medical implant according to the invention is that it possesses good bending flexibility and can expand well from the smallest possible compression state to the largest possible expansion state. This expansion is preferably achieved spontaneously by using a suitable hyperelastic material (e.g., shape memory alloy). In this regard, the support structure can be particularly self-expanding. The implant can also be made of or composed of shape memory plastic.

[0029] While the preferred embodiment of the invention proposes that the grid elements of the support structure comprise or are composed of self-expanding shape memory alloys (such as nitinol), it is also conceivable that the support structure be made of spherically expandable materials (such as stainless steel or CoCr alloys). A particularly short length and / or particularly high radial force is particularly advantageous for the support structure.

[0030] In terms of bending flexibility and expansion capability, good flexibility of the implant can be achieved by appropriately setting the ratio between the total thickness of the membrane and the height of the grid elements or the wall thickness of the supporting structure. In a particularly preferred variant, the membrane thickness is at most 40%, at most 30%, at most 20%, and at most 10% of the height of the grid elements, particularly the height of the connecting strips or wires.

[0031] In a monolithically formed support structure, the height of the grid element corresponds to the height of the connecting strip or the wall thickness of the support structure. In a support structure formed by interwoven wires, the height of the grid element corresponds to the wire thickness. The overall wall thickness of the support structure differs because the wires cross at the top in some places, therefore the wall thickness of the support structure is twice the height of the grid element (i.e., the wire diameter). In any case, the total layer thickness of the membrane is finite, thus ensuring that the membrane has high flexibility so that it can well follow the bending or expansion of the support structure.

[0032] Furthermore, it is beneficial for the overall flexibility of the implant that, as preferably proposed, the height of the mesh element, particularly the height of the connecting strip or wire, is between 40 µm and 160 µm, particularly between 40 µm and 150 µm, particularly between 40 µm and 130 µm, particularly between 40 µm and 110 µm, particularly between 40 µm and 100 µm, particularly between 50 µm and 90 µm, particularly between 50 µm and 80 µm.

[0033] Generally, for preferred variations of the implant according to the invention, the ratio between the thickness of the membrane and the height of the mesh elements (especially connecting strips or wires) is specified to be at most 1 / 3, particularly at most 1 / 4, particularly at most 1 / 5, particularly at most 1 / 8, particularly at most 1 / 10, particularly at most 1 / 12, particularly at most 1 / 15, particularly at most 1 / 20. In other words, the height of the mesh elements is preferably 2 to 10 times, particularly 3 to 8 times, particularly 4 to 6 times, the overall thickness of the membrane.

[0034] Furthermore, it is advantageous that the implant is clearly visible under radiographic examination. This makes it easy for surgeons to determine the implant's location within the blood vessel and to check whether the membrane is functioning properly (shielding the aneurysm while simultaneously providing adequate perfusion to branch vessels or arterioles). In this regard, it can be suggested that the implant is at least partially or locally made of a radiopaque material. This material can be gold, platinum, or tantalum, or their alloys.

[0035] For example, radiographic markers, such as loops, coils, or sleeves, can be arranged at the longitudinal ends of the support structure. In particular, it is advantageous to have three radiographic markers at each longitudinal end to make the implant identifiable. Such radiographic markers can also be additionally or alternatively arranged in the middle region of the support structure. Additional threads with improved radiopaque linearity can also be incorporated into the support structure. Specifically, such threads can be wound along a series of flush mesh elements. These threads can be formed from so-called DFT (drawn filled tube) wire.

[0036] Furthermore, it is conceivable that at least the individual grid elements of the support structure include a radiopaque core material covered by a shape memory material (DFT wire). Similarly, at least individual fibers of the membrane, preferably all fibers, are provided with a radiopaque core material and an overlay made of another material (e.g., polyurethane). To improve radiopaque linearity, the radiopaque material can also be arranged between the functional layer and the support layer. Thus, at least one radiopaque nonwoven fabric or at least one radiopaque strip can be arranged between the functional layer and the support layer, for example. Finally, the radiopaque material (especially tantalum, niobium, platinum, or gold) can also be applied to or integrated into the support structure by means of sputtering techniques (especially by magnetron sputtering). The fibers can also be formed from a plastic mixed with the radiopaque material. For example, the plastic can be mixed with at least 20% barium sulfate, such that the membrane is at least visible in still radiographic images.

[0037] In another embodiment of the invention, the implant is provided with an antithrombotic coating such that each fiber of the membrane is coated. The advantage of this coating is that the pores of the membrane formed by the movement of the membrane fibers remain open and are not closed by platelet accumulation.

[0038] Preferably, the coating thickness is at most 10 nm. The coating may include fibrin and / or heparin. In particular, the coating may have heparin covalently bound to fibrin. Such a coating is described in the applicant's DE 10 2018110 591 A1, which mentions the composition of the coating.

[0039] Generally speaking, the membrane described herein can be used not only (as part of the implant according to the invention) for the treatment of aneurysms, but also for other cerebrovascular disease applications. An example of this is the treatment of arteriovenous malformations (so-called AVMs) and arteriovenous fistulas. Here, the porosity and flexibility of the membrane can be set such that the arteriovenous shunt still supplies blood to the vein, but the pressure of the inflowing blood and thus accumulated in the vein no longer causes the vein to rupture.

[0040] The membrane as a whole can be manufactured using an electrospinning process. For example, the functional layer and the support layer can be manufactured independently through electrospinning and then combined on a support structure. The nonwoven (Vlies-artig) structure of the electrospinned functional layer and the electrospinned support layer binds these two layers together to form a uniform membrane, because the fibers of the support layer are applied directly to the fibers of the functional layer through electrospinning and are thus material-determined connected to them. The process parameters and / or materials used to manufacture the functional layer and the support layer differ to reflect their different functions. However, the functional layer and the support layer can also be produced in a common manufacturing step. For this purpose, an electrospinning process can be used, in which different materials are deposited simultaneously to directly generate a membrane that functions as both the functional layer and the support layer. It is generally desirable that the overall thickness of the membrane, as well as the thicknesses of the functional layer and the support layer, be substantially constant along the length of the membrane. However, it is also meaningful to vary the aforementioned thicknesses along the length of the membrane.

[0041] In a preferred embodiment of the invention, the functional layer is provided with perforations in the areas of the mesh openings. These perforations may specifically be lobes, straight sutures, curved sutures, and / or T-shaped sutures. The perforations create openings in the functional layer, which facilitate localized opening of the functional layer when there is a pressure difference between the fluid pressure in the internal through-channels of the support structure and the fluid pressure outside the support layer. A support layer disposed on the functional layer restricts the opening process, preventing the openings or perforations from expanding excessively. This ensures opening even under low pressure gradients. Here, the perforations are preferably designed to achieve localized opening of the functional layer in areas subject to pressure gradients typically present between the main vessel and branch vessels or perforators. Specifically, the perforations are configured such that the functional layer does not open in areas with low pressure gradients (e.g., pressure gradients typically formed between the main vessel and aneurysms). However, localized opening of the functional layer should be achieved to allow blood flow into the perforators.

[0042] Perforation can be created by laser processing of the membrane, especially the functional layer, and / or by solvent spraying.

[0043] In laser processing, the functional layer can be patterned with perforations using a UV laser or a femtosecond or picosecond infrared laser. Holes, straight sutures or incisions, kiemenartig-like bends and / or T-shaped sutures or incisions are specifically considered perforation patterns. A patterned distribution of perforations over a large area of ​​the membrane is generally preferred. Therefore, it is important to ensure that perforations are present before any covered collateral vessels during implantation, allowing fluid to pass through the membrane into the collateral vessels.

[0044] In solvent spraying, a mist is generated consisting of microdroplets of solvent or solvent-polymer mixture of a certain size. When the mist impacts the functional layer, the fibers of the functional layer are dissolved, thereby forming pores in the functional layer.

[0045] Furthermore, it is conceivable that perforations could be created during the fabrication of films, particularly functional layers, using masks. Thus, the functional layer could be masked, allowing perforation patterns to be created or left exposed during the formation of the functional layer via a spray coating process. This manufacturing variation is particularly well-suited for forming pores as perforation patterns.

[0046] Preferably, the medical implant according to the present invention can be manufactured by a method comprising the following steps: a. Provide supporting structure; b. Apply the functional layer to the supporting structure; c. Perforating the functional layer using laser cutting or solvent spraying; and d. Apply the support layer to the functional layer.

[0047] As an alternative to forming perforations using laser cutting or solvent spraying, functional layers can also have perforations created by leaving areas undefined during the application of the functional layer. This can be achieved, for example, by using a mask placed on a support structure before the functional layer is applied and then removed afterward.

[0048] The described method enables the simple and efficient manufacture of implants with smart membranes that can be locally opened due to a correspondingly high pressure gradient to allow fluid to pass through.

[0049] Furthermore, it can be proposed that an additional support layer be arranged between the supporting structure and the functional layer. The fiber thickness of the additional support layer can be greater than that of the functional layer. Moreover, the fiber density of the support layer can be less than that of the functional layer. Attached Figure Description

[0050] The invention will now be described in more detail based on embodiments and with reference to the accompanying schematic diagrams. In the drawings: Figure 1 A portion of a vascular system is shown, in which a medical implant according to the invention is inserted; Figure 2 It shows according to Figure 1 Details of the implant covering the aneurysm; Figure 3 It shows according to Figure 1 Details of the implant covering branch vessels; and Figures 4 to 7Side views of the medical implant according to the invention, based on a preferred embodiment, are shown, wherein the functional layers each have different perforations. Detailed Implementation

[0051] Figure 1 This diagram shows a portion of a vascular system with the main vessel MV and three collateral vessels BV1, BV2, and BV3 branching from the main vessel MV. The main vessel MV also has an aneurysm AN located between the second collateral vessel BV2 and the third collateral vessel BV3. In particular, the aneurysm is located near the third collateral vessel BV3.

[0052] The medical implant according to the invention is used to treat aneurysms (AN). The medical implant includes a support structure 1 formed of a mesh structure 10, which is composed of mesh elements. The mesh elements may be connecting strips 12 integrally connected to each other, thus forming the mesh structure 10. Here, the connecting strips 12 define units 13 of the mesh structure 10. Alternatively, the mesh structure 10 may also be formed of interwoven wires. To make the mesh structure 10 or the support structure 1 visible under radiographic examination when the implant is inserted into the vascular system or the main blood vessel (MV), radiographic markers 11 are provided at the longitudinal ends of the mesh structure 10. Preferably, a plurality of radiographic markers 11 are arranged at each longitudinal end of the mesh structure 10, and these radiographic markers 11 are positioned at regular intervals in the circumferential direction of the mesh structure 10.

[0053] The implant also has a membrane 2, which includes an intracavitary functional layer 4 and an extracavitary support layer 3. Preferably, the functional layer 4 and the support layer 3 completely overlap, so that they have the same length in the longitudinal direction of the mesh structure 10. However, preferably, the support layer 3 extends beyond the functional layer 4 at least at its longitudinal ends, preferably by several millimeters. Figure 1 As can be seen, the mesh structure 10 can be longer than the membrane 2.

[0054] The implant is positioned in the main blood vessel MV such that the implant (specifically membrane 2) completely covers the neck of the aneurysm AN. Furthermore, an embolization medium 30 may also be placed within the aneurysm AN. Specifically, the medical implant may be provided alone or as a kit with the embolization medium 30. The embolization medium 30 may be, for example, a gel. Alternatively, the embolization medium 30 may also be formed from a coil (i.e., a disordered winding of microwires). After the implant is inserted into the main blood vessel MV, the embolization medium 30 can be placed into the aneurysm AN. For example, the coil can be delivered into the aneurysm through membrane 2 via a microcatheter. Here, membrane 2 or its fibers are flexible, so the microcatheter can enlarge the pores of membrane 2, thereby opening a pathway into the aneurysm AN.

[0055] exist Figure 1It can also be seen that membrane 2 not only crosses the aneurysm AN, but also the second collateral vessel BV2 and the third collateral vessel BV3. This is the special function of membrane 2. Membrane 2 includes an extraluminal support layer 3, which has a greater porosity than the intraluminal functional layer 4. Here, the support layer 3 is porous, making it permanently permeable to blood. In contrast, the functional layer 4 has essentially lower blood permeability, particularly semi-permeability, and is mainly less permeable than the support layer 3. However, the functional layer 4 is also flexible, so that when a corresponding force is applied, the functional layer 4 becomes permeable to blood or more permeable to blood. This required force can be generated by the pressure gradient that appears between the blood pressure in the main vessel MV and the decreasing blood pressure in one of the collateral vessels BV1, BV2, and BV3.

[0056] Because the functional layer initially reduces blood flow into the collateral vessels BV1, BV2, and BV3, a pressure gradient, or a stronger one, is created between the blood pressure in the main vessel MV and the corresponding collateral vessels BV1, BV2, and BV3. This pressure gradient generates a force high enough to widen the pores of the functional layer 4. This is achieved by the elastic and / or plastic deformation and / or mutual sliding of the filaments of the functional layer 4, such that the functional layer 4 becomes blood-permeable or more permeable only in the regions of the branch vessels (i.e., locally in the regions where the openings into the corresponding collateral vessels BV1, BV2, and BV3 are located). In this respect, membrane 2 is "intelligent" because it provides blood flow only where the pressure gradient between the blood pressure in the main vessel MV and the pressure outside the adventitia 50 is sufficiently high. This threshold is frequently exceeded at the locations where membrane 2 locally covers the collateral vessels BV1, BV2, and BV3 branching from the main vessel MV. At the location where membrane 2 crosses the aneurysm AN opening from the main vessel MV, the pressure threshold is not exceeded; that is, the pressure gradient between the blood pressure in the main vessel MV and the pressure within the aneurysm AN is not large enough to enlarge the pores of functional layer 4. Therefore, the aneurysm AN remains shielded from blood flow, causing the blood remaining in the aneurysm AN to coagulate within a short time, thus causing the aneurysm AN to shrink.

[0057] If according to Figure 1 As proposed in the embodiments, the additional placement of the embolic medium 30 within the aneurysm also serves to retain the embolic medium 30 within the aneurysm AN, preventing it from migrating back into the main vessel MV. This further ensures rapid shrinkage of the aneurysm AN.

[0058] Figure 2 and Figure 3 A portion of an implant having a support structure 1 and a membrane 2 is shown. The support structure 1 is formed of a mesh structure 10, in which... Figure 2 and Figure 3 The diagram shows several connecting strips 12 of the mesh structure. These connecting strips 12 form the units 13 of the mesh structure 10. In the illustrated embodiment, the connecting strips 12 are integrally connected to each other. Therefore, the mesh structure 10 is formed monolithically. However, the mesh structure 10 can also be formed from interwoven or braided wires.

[0059] Membrane 2 spans across unit 13. Membrane 2 comprises at least two layers, each formed of electrospun yarns. The yarns in these layers have different thicknesses and densities.

[0060] Specifically, membrane 2 has a support layer 3 with a relatively low filament density and a relatively high filament thickness. Therefore, support layer 3 differs from functional layer 4, which has a smaller filament thickness. Furthermore, the filament density of functional layer 4 is higher than that of support layer 3. In other words, support layer 3 and functional layer 4 each have pores 5 defined by filaments, with the pores in support layer 3 being larger than those in functional layer 4. This applies in all cases to the resting state of the implant, i.e., without external force.

[0061] The function of the functional layer 4 is to impede or at least slow down the blood flow through the membrane 2. In this respect, the functional layer 4 acts as a deflector, i.e., to deflect the blood flow along its surface. Due to the relatively small thickness of the filaments, the functional layer is relatively flexible. The support layer 3 stabilizes the functional layer 4 and prevents it from bulging in the radial direction, or keeps the functional layer 4 in close contact with the support structure 1.

[0062] Figure 2 The principle of blood flow deflection is illustrated. A membrane 2 extending on unit 13 crosses the aneurysm AN. There is almost no significant pressure gradient between the aneurysm AN and the main vessel MV into which the implant is inserted, so the functional layer 4 remains essentially at rest. Therefore, the pore size of the functional layer 4 is small, so that blood flow is primarily guided along the functional layer 4 and essentially does not enter the aneurysm AN. Thus, the aneurysm AN is largely separated from the blood flow in the main vessel MV and can shrink by causing the blood remaining in the aneurysm AN to clot. However, a small amount of blood flow may flow into the aneurysm through the pores of the membrane, so the coagulation process and solid thrombus formation in the aneurysm are not interrupted.

[0063] Figure 3The function of functional layer 4 across a branch vessel (e.g., the second collateral vessel BV2) is illustrated. Due to the pressure difference between the main vessel MV and the second collateral vessel BV2, the filaments of functional layer 4 deflect or locally deform. Consequently, the pores of functional layer 4 enlarge in the ostial region of the second collateral vessel BV2. In contrast, the filaments of supporting layer 3 are more stable and largely remain in place. However, the pores of supporting layer 3 are already large enough to allow blood flow through it. Therefore, the expansion of the pores of functional layer 4 in the ostial region of the second collateral vessel BV2 is sufficient to allow adequate blood flow from the main vessel MV to the second collateral vessel BV2.

[0064] exist Figures 4 to 7 Various embodiments of a medical implant with a functional layer 4 equipped with perforations 14 are shown. For clarity, in Figures 4 to 7 Support layer 3 is not shown.

[0065] Specifically, Figures 4 to 7 A support structure 1 is shown, which has a support structure 1 configured as a grid structure 10. The grid structure 10 includes a plurality of integrally connected strips 12 defining units 13. Ray markers 11 are arranged at the longitudinal ends of the grid structure 10. In the middle region of the grid structure 10, a membrane 2 is provided with a functional layer 4. The membrane 2 extends over the entire periphery of the grid structure 10 and completely covers the units 13. The membrane 2 is connected to the connecting strips 12 of the grid structure 10.

[0066] Figures 4 to 7 The functional layer 4 shown has perforations 14. The perforations 14 are preferably arranged in a distributed pattern on the functional layer 4. Specifically, the perforations 14 are located in the areas of the grid openings or cells 13 of the support structure 1. Regarding the pattern arrangement of the perforations 14, according to... Figures 4 to 7 The embodiments shown have similarities. Therefore, in the illustrated embodiment, it is proposed that the density of perforations 14 in the units 13 arranged near the longitudinal ends of the functional layer 4 is higher than the density of perforations 14 in the units 13 in the middle region of the functional layer 4. When the implant is positioned in the region of the aneurysm AN, it should be ensured that blood flow into the aneurysm AN is interrupted to some extent. Therefore, local opening of the functional layer 4 in the region of the aneurysm AN is undesirable. Typically, the implant is positioned such that the middle region of the implant (especially the functional layer 4) is located in the region of the aneurysm AN. However, due to the presence of perforations 14 in this region (albeit at a lower density), the collateral vessels BV1, BV2, and BV3 of the branch opposite the aneurysm AN can still receive a good supply of nutrients because the perforations 14 allow the functional layer 4 to be open. In the edge region of the functional layer 4, the probability of covering the collateral vessels BV1, BV2, and BV3 is higher. The perforations 14 positioned here have greater permeability.

[0067] The difference between embodiments 4 to 7 lies in the type of perforation 14 in functional layer 4. Therefore, Figure 4 One embodiment is shown in which the functional layer 4 has perforations 14 formed by holes 14a. The holes 14a are substantially located in the areas of the covering mesh openings or cells 13 of the functional layer 4. The number of holes 14a in the cells 13 arranged at the longitudinal ends of the functional layer 4 is greater than the number of holes 14a in the middle region of the functional layer 4.

[0068] According to Figure 5 In one embodiment, the perforation 14 is formed by a straight slit 14b extending parallel to the longitudinal axis of the mesh structure 10. Other orientations of the straight slit 14b are possible. In particular, the straight slits 14b may be arranged at an angle between 0° and 180° relative to the longitudinal axis of the implant projected onto the wall plane of the implant.

[0069] According to Figure 5 In this embodiment, the length of the seam 14b is adapted to the available space between adjacent connecting strips 12 in the longitudinal direction of the mesh structure 10, thus the seams 14b have different lengths. The spacing of the seams 14b in the circumferential direction of the mesh structure 10 is also different, wherein the spacing provided in the edge region of the functional layer 4 is smaller than the spacing in the middle region of the functional layer 4.

[0070] according to Figure 6 The embodiment illustrates an implant having a functional layer 4 with perforations 14 formed by slits 14c. The slits 14c extend substantially in the circumferential direction of the mesh structure 10. Two slits 14c are arranged in each cell 13 in the edge region of the functional layer 4, while one slit 14c is assigned to each cell 13 in the middle region of the functional layer 4. Other numbers and distributions of the perforations 14 are feasible.

[0071] Preferably, the bends 14c are oriented in the same direction, particularly in the direction of blood flow. In other words, according to Figure 6 The implant is preferably placed in a blood vessel, such that blood flows from the longitudinal end of the bend 14c to the apex of its bend. Therefore, according to... Figure 6 In the illustration, blood flows from the left end of the mesh structure 10 to the right end of the mesh structure 10. In this respect, the slit 14c forms a gill-like opening in the functional layer 4.

[0072] Generally, in all embodiments with perforations 14, the support layer 3 has a constraint function for opening the perforations 14. Particularly in the open gill-like embodiments, the perforations open by deflection of a portion of the functional layer 4. This deflection is constrained by the support layer 3, which in this respect has a valve-like constraint function for opening the perforations 14. Therefore, the constraint function of the support layer 3 and the perforations 14 of the functional layer 4 are coordinated such that the perforations 14 open only when a predetermined pressure gradient exists between the inner and outer sides of the membrane 2.

[0073] Figure 7 The following embodiment is shown, wherein the perforations 14 of the functional layer 4 are formed by T-shaped sutures 14d. Similarly, in this embodiment, each unit 13 has more T-shaped sutures 14d in the edge region of the functional layer 4 than in the middle region of the functional layer 4. Preferably, the T-shaped sutures 14d are oriented in the same direction. Specifically, each T-shaped suture 14d includes a main suture 14d' and a transverse suture 14d'', wherein the main suture 14d' extends parallel to the longitudinal axis of the mesh structure 10, while the transverse suture 14d'' extends perpendicular to the longitudinal axis. The transverse suture 14d'' connects to the distal longitudinal end of the main suture 14d'. The implant is preferably placed in a blood vessel such that blood flows from the proximal end of the main suture 14d' to the transverse suture 14d''.

[0074] Reference tag list 1 Supporting Structure 2 membranes 3 Support Layers 4 functional layers 5 holes 10 grid structure 11-ray markers 12 connecting strips Unit 13 14 perforations 14a hole 14b straight seam 14c bend 14d T-shaped seam 14d' main seam 14d'' Horizontal seam 30 Embolizing Media AN aneurysm BV1 first collateral vessel BV2 second collateral vessel BV3 third collateral vessel MV main blood vessel.

Claims

1. A medical implant for treating aneurysms, the medical implant having a support structure (1) having a compressible and expandable mesh structure (10) composed of mesh elements, the mesh elements defining mesh openings, wherein, The mesh structure (10) is at least partially covered by a membrane (2) made of fibers, the membrane comprising at least one intracavitary functional layer (4) and at least one extracavitary support layer (3), the functional layer and the support layer each having pores, wherein the porosity of the functional layer (4) is less than the porosity of the support layer (3). Its features are, The membrane (2) is configured such that the pores of at least the functional layer (4) open due to the pressure gradient between the liquid pressure in the internal through-channel of the support structure (1) and the liquid pressure outside the support layer (3) to increase the liquid flow rate through the membrane (2).

2. The medical implant according to claim 1, characterized in that, The fibers of the membrane (2) are loosely arranged at the intersections such that the intersecting fibers at the intersections can move relative to each other, and / or at least the fibers of the functional layer (4) of the membrane (2) are elastically deformable and / or plastically deformable.

3. The medical implant according to claim 1, characterized in that, The fiber thickness of the fibers in the functional layer (4) of the membrane (2) is less than 500 nm, and / or the fiber thickness of the fibers in the support layer (3) of the membrane (2) is at least 500 nm.

4. The medical implant according to claim 2, characterized in that, The fiber thickness of the fibers in the functional layer (4) of the membrane (2) is less than 500 nm, and / or the fiber thickness of the fibers in the support layer (3) of the membrane (2) is at least 500 nm.

5. The medical implant according to any one of claims 1-4, characterized in that, The thickness of the functional layer (4) of the membrane (2) is at most 10 µm, and / or the thickness of the support layer (3) of the membrane (2) is at least 3 µm.

6. The medical implant according to any one of claims 1-4, characterized in that, The porosity of the functional layer (4) of the membrane (2) is less than 50%, and / or the porosity of the support layer (3) of the membrane (2) is at least 50%.

7. The medical implant according to claim 5, characterized in that, The porosity of the functional layer (4) of the membrane (2) is less than 50%, and / or the porosity of the support layer (3) of the membrane (2) is at least 50%.

8. The medical implant according to any one of claims 1-4 and 7, characterized in that, The functional layer (4) of the membrane (2) is at 100,000 µm 2 The area includes at least 10 holes, the inscribed circle diameter of the at least 10 holes being at most 10 µm, and / or, the support layer (3) of the membrane (2) is 100,000 µm. 2 The area includes at least 5 holes, the inscribed circle diameter of which is at least 10 µm.

9. The medical implant according to claim 5, characterized in that, The functional layer (4) of the membrane (2) is at 100,000 µm 2 The area includes at least 10 holes, the inscribed circle diameter of the at least 10 holes being at most 10 µm, and / or, the support layer (3) of the membrane (2) is 100,000 µm. 2 The area includes at least 5 holes, the inscribed circle diameter of which is at least 10 µm.

10. The medical implant according to claim 6, characterized in that, The functional layer (4) of the membrane (2) is at 100000µm 2 The area includes at least 10 holes, the inscribed circle diameter of the at least 10 holes being at most 10 µm, and / or, the support layer (3) of the membrane (2) is 100,000 µm. 2 The area includes at least 5 holes, the inscribed circle diameter of which is at least 10 µm.

11. The medical implant according to any one of claims 1-4, 7 and 9-10, characterized in that, The fibers of the functional layer (4) have a smaller fiber thickness than the fibers of the support layer (3), and / or the fibers of the functional layer (4) have higher extensibility than the fibers of the support layer (3).

12. The medical implant according to claim 5, characterized in that, The fibers of the functional layer (4) have a smaller fiber thickness than the fibers of the support layer (3), and / or the fibers of the functional layer (4) have higher extensibility than the fibers of the support layer (3).

13. The medical implant according to claim 6, characterized in that, The fibers of the functional layer (4) have a smaller fiber thickness than the fibers of the support layer (3), and / or the fibers of the functional layer (4) have higher extensibility than the fibers of the support layer (3).

14. The medical implant according to claim 8, characterized in that, The fibers of the functional layer (4) have a smaller fiber thickness than the fibers of the support layer (3), and / or the fibers of the functional layer (4) have higher extensibility than the fibers of the support layer (3).

15. The medical implant according to any one of claims 1-4, 7, 9-10 and 12-14, characterized in that, The fibers of the functional layer (4) are formed of a material having a lower Shore hardness than the material of the fibers of the support layer (3), wherein the Shore hardness of the material of the fibers of the functional layer (4) is at most 90A, and / or the Shore hardness of the material of the fibers of the support layer (3) is at least 90A.

16. The medical implant according to claim 5, characterized in that, The fibers of the functional layer (4) are formed of a material having a lower Shore hardness than the material of the fibers of the support layer (3), wherein the Shore hardness of the material of the fibers of the functional layer (4) is at most 90A, and / or the Shore hardness of the material of the fibers of the support layer (3) is at least 90A.

17. The medical implant according to claim 6, characterized in that, The fibers of the functional layer (4) are formed of a material having a lower Shore hardness than the material of the fibers of the support layer (3), wherein the Shore hardness of the material of the fibers of the functional layer (4) is at most 90A, and / or the Shore hardness of the material of the fibers of the support layer (3) is at least 90A.

18. The medical implant according to claim 8, characterized in that, The fibers of the functional layer (4) are formed of a material having a lower Shore hardness than the material of the fibers of the support layer (3), wherein the Shore hardness of the material of the fibers of the functional layer (4) is at most 90A, and / or the Shore hardness of the material of the fibers of the support layer (3) is at least 90A.

19. The medical implant according to claim 11, characterized in that, The fibers of the functional layer (4) are formed of a material having a lower Shore hardness than the material of the fibers of the support layer (3), wherein the Shore hardness of the material of the fibers of the functional layer (4) is at most 90A, and / or the Shore hardness of the material of the fibers of the support layer (3) is at least 90A.

20. The medical implant according to any one of claims 1-4, 7, 9-10, 12-14, and 16-19, characterized in that, The membrane (2) has thermoplastic polyurethane or is formed of thermoplastic polyurethane.

21. The medical implant according to claim 5, characterized in that, The membrane (2) has thermoplastic polyurethane or is formed of thermoplastic polyurethane.

22. The medical implant according to claim 6, characterized in that, The membrane (2) has thermoplastic polyurethane or is formed of thermoplastic polyurethane.

23. The medical implant according to claim 8, characterized in that, The membrane (2) has thermoplastic polyurethane or is formed of thermoplastic polyurethane.

24. The medical implant according to claim 11, characterized in that, The membrane (2) has thermoplastic polyurethane or is formed of thermoplastic polyurethane.

25. The medical implant according to claim 15, characterized in that, The membrane (2) has thermoplastic polyurethane or is formed of thermoplastic polyurethane.

26. The medical implant according to any one of claims 1-4, 7, 9-10, 12-14, 16-19 and 21-25, characterized in that, The membrane (2) extends completely around the periphery of the support structure (1).

27. The medical implant according to claim 5, characterized in that, The membrane (2) extends completely around the periphery of the support structure (1).

28. The medical implant according to claim 6, characterized in that, The membrane (2) extends completely around the periphery of the support structure (1).

29. The medical implant according to claim 8, characterized in that, The membrane (2) extends completely around the periphery of the support structure (1).

30. The medical implant according to claim 11, characterized in that, The membrane (2) extends completely around the periphery of the support structure (1).

31. The medical implant according to claim 15, characterized in that, The membrane (2) extends completely around the periphery of the support structure (1).

32. The medical implant according to claim 20, characterized in that, The membrane (2) extends completely around the periphery of the support structure (1).

33. The medical implant according to any one of claims 1-4, 7, 9-10, 12-14, 16-19, 21-25 and 27-32, characterized in that, The support structure (1) is integrally formed, wherein the grid cells of the grid structure (10) form connecting strips (12), and the connecting strips define the grid openings of the grid structure (10) as cells (13).

34. The medical implant according to claim 5, characterized in that, The support structure (1) is integrally formed, wherein the grid cells of the grid structure (10) form connecting strips (12), and the connecting strips define the grid openings of the grid structure (10) as cells (13).

35. The medical implant according to claim 6, characterized in that, The support structure (1) is integrally formed, wherein the grid cells of the grid structure (10) form connecting strips (12), and the connecting strips define the grid openings of the grid structure (10) as cells (13).

36. The medical implant according to claim 8, characterized in that, The support structure (1) is integrally formed, wherein the grid cells of the grid structure (10) form connecting strips (12), and the connecting strips define the grid openings of the grid structure (10) as cells (13).

37. The medical implant according to claim 11, characterized in that, The support structure (1) is integrally formed, wherein the grid cells of the grid structure (10) form connecting strips (12), and the connecting strips define the grid openings of the grid structure (10) as cells (13).

38. The medical implant according to claim 15, characterized in that, The support structure (1) is integrally formed, wherein the grid cells of the grid structure (10) form connecting strips (12), and the connecting strips define the grid openings of the grid structure (10) as cells (13).

39. The medical implant according to claim 20, characterized in that, The support structure (1) is integrally formed, wherein the grid cells of the grid structure (10) form connecting strips (12), and the connecting strips define the grid openings of the grid structure (10) as cells (13).

40. The medical implant according to claim 26, characterized in that, The support structure (1) is integrally formed, wherein the grid cells of the grid structure (10) form connecting strips (12), and the connecting strips define the grid openings of the grid structure (10) as cells (13).

41. The medical implant according to any one of claims 1-4, 7, 9-10, 12-14, 16-19, 21-25, 27-32 and 34-40, characterized in that, The support structure (1) has interwoven wires, wherein the wires form grid elements of the grid structure (10) and define grid openings in the grid structure (10) as meshes.

42. The medical implant according to claim 5, characterized in that, The support structure (1) has interwoven wires, wherein the wires form grid elements of the grid structure (10) and define grid openings in the grid structure (10) as meshes.

43. The medical implant according to claim 6, characterized in that, The support structure (1) has interwoven wires, wherein the wires form grid elements of the grid structure (10) and define grid openings in the grid structure (10) as meshes.

44. The medical implant according to claim 8, characterized in that, The support structure (1) has interwoven wires, wherein the wires form grid elements of the grid structure (10) and define grid openings in the grid structure (10) as meshes.

45. The medical implant according to claim 11, characterized in that, The support structure (1) has interwoven wires, wherein the wires form grid elements of the grid structure (10) and define grid openings in the grid structure (10) as meshes.

46. ​​The medical implant according to claim 15, characterized in that, The support structure (1) has interwoven wires, wherein the wires form grid elements of the grid structure (10) and define grid openings in the grid structure (10) as meshes.

47. The medical implant according to claim 20, characterized in that, The support structure (1) has interwoven wires, wherein the wires form grid elements of the grid structure (10) and define grid openings in the grid structure (10) as meshes.

48. The medical implant according to claim 26, characterized in that, The support structure (1) has interwoven wires, wherein the wires form grid elements of the grid structure (10) and define grid openings in the grid structure (10) as meshes.

49. The medical implant according to claim 33, characterized in that, The support structure (1) has interwoven wires, wherein the wires form grid elements of the grid structure (10) and define grid openings in the grid structure (10) as meshes.

50. The medical implant according to claim 49, characterized in that, The total thickness of the membrane (2) is a maximum of 40% of the height of the grid element.

51. The medical implant according to claim 49 or 50, characterized in that, The height of the grid element is between 40 µm and 160 µm.

52. The medical implant according to claim 49 or 50, characterized in that, The ratio between the thickness of the membrane (2) and the height of the grid element is at most 1 / 3.

53. The medical implant according to claim 51, characterized in that, The ratio between the thickness of the membrane (2) and the height of the grid element is at most 1 / 3.

54. The medical implant according to any one of claims 1-4, 7, 9-10, 12-14, 16-19, 21-25, 27-32, 34-40, 42-50 and 53, characterized in that, The functional layer (4) has perforations in the area of ​​the grid opening.

55. The medical implant according to claim 5, characterized in that, The functional layer (4) has perforations in the area of ​​the grid opening.

56. The medical implant according to claim 6, characterized in that, The functional layer (4) has perforations in the area of ​​the grid opening.

57. The medical implant according to claim 8, characterized in that, The functional layer (4) has perforations in the area of ​​the grid opening.

58. The medical implant according to claim 11, characterized in that, The functional layer (4) has perforations in the area of ​​the grid opening.

59. The medical implant according to claim 15, characterized in that, The functional layer (4) has perforations in the area of ​​the grid opening.

60. The medical implant according to claim 20, characterized in that, The functional layer (4) has perforations in the area of ​​the grid opening.

61. The medical implant according to claim 26, characterized in that, The functional layer (4) has perforations in the area of ​​the grid opening.

62. The medical implant according to claim 33, characterized in that, The functional layer (4) has perforations in the area of ​​the grid opening.

63. The medical implant according to claim 41, characterized in that, The functional layer (4) has perforations in the area of ​​the grid opening.

64. The medical implant according to claim 51, characterized in that, The functional layer (4) has perforations in the area of ​​the grid opening.

65. The medical implant according to claim 52, characterized in that, The functional layer (4) has perforations in the area of ​​the grid opening.

66. The medical implant according to claim 54, characterized in that, The perforation is formed by a hole (14a), a straight seam (14b), a curved seam (14c), and / or a T-shaped seam (14d).

67. The medical implant according to any one of claims 55-65, characterized in that, The perforation is formed by a hole (14a), a straight seam (14b), a curved seam (14c), and / or a T-shaped seam (14d).

68. The medical implant according to claim 1, characterized in that, The membrane (2) is an electrospun membrane.

69. The medical implant according to claim 2, characterized in that, The fibers of the intracavitary functional layer (4) are loosely arranged at their intersections.

70. The medical implant according to claim 3 or 4, characterized in that, The fiber thickness of the functional layer (4) of the membrane (2) is up to 400 nm.

71. The medical implant according to claim 70, characterized in that, The fiber thickness of the functional layer (4) of the membrane (2) is up to 300 nm.

72. The medical implant according to claim 71, characterized in that, The fiber thickness of the functional layer (4) of the membrane (2) is up to 200 nm.

73. The medical implant according to claim 72, characterized in that, The fiber thickness of the functional layer (4) of the membrane (2) is up to 100 nm.

74. The medical implant according to claim 3 or 4, characterized in that, The fiber thickness of the support layer (3) of the membrane (2) is at least 750 nm.

75. The medical implant according to claim 74, characterized in that, The fiber thickness of the support layer (3) of the membrane (2) is at least 1000 nm.

76. The medical implant according to claim 75, characterized in that, The fiber thickness of the support layer (3) of the membrane (2) is at least 1250 nm.

77. The medical implant according to claim 76, characterized in that, The fiber thickness of the fiber in the support layer (3) of the membrane (2) is at least 1500 nm.

78. The medical implant according to claim 5, characterized in that, The thickness of the functional layer (4) of the membrane (2) is less than 10 µm.

79. The medical implant according to claim 78, characterized in that, The maximum thickness of the functional layer (4) of the membrane (2) is 8 µm.

80. The medical implant according to claim 79, characterized in that, The maximum thickness of the functional layer (4) of the membrane (2) is 6 µm.

81. The medical implant according to claim 80, characterized in that, The maximum thickness of the functional layer (4) of the membrane (2) is 4 µm.

82. The medical implant according to claim 81, characterized in that, The maximum thickness of the functional layer (4) of the membrane (2) is 2 µm.

83. The medical implant according to claim 5, characterized in that, The thickness of the support layer (3) of the membrane (2) is at least 5 µm.

84. The medical implant according to claim 83, characterized in that, The thickness of the support layer (3) of the membrane (2) is at least 6 µm.

85. The medical implant according to claim 84, characterized in that, The thickness of the support layer (3) of the membrane (2) is at least 7 µm.

86. The medical implant according to claim 85, characterized in that, The thickness of the support layer (3) of the membrane (2) is at least 8µm.

87. The medical implant according to claim 6, characterized in that, The porosity of the functional layer (4) of the membrane (2) is up to 40%.

88. The medical implant according to claim 87, characterized in that, The porosity of the functional layer (4) of the membrane (2) is up to 30%.

89. The medical implant according to claim 6, characterized in that, The porosity of the support layer (3) of the membrane (2) is at least 60%.

90. The medical implant according to claim 89, characterized in that, The porosity of the support layer (3) of the membrane (2) is at least 70%.

91. The medical implant according to claim 90, characterized in that, The porosity of the support layer (3) of the membrane (2) is at least 80%.

92. The medical implant according to claim 91, characterized in that, The porosity of the support layer (3) of the membrane (2) is at least 90%.

93. The medical implant according to claim 8, characterized in that, The maximum diameter of the inscribed circle of the at least 10 holes is 8 µm.

94. The medical implant according to claim 93, characterized in that, The maximum diameter of the inscribed circle of the at least 10 holes is 6 µm.

95. The medical implant according to claim 94, characterized in that, The maximum diameter of the inscribed circle of the at least 10 holes is 4 µm.

96. The medical implant according to claim 95, characterized in that, The maximum diameter of the inscribed circle of the at least 10 holes is 2 µm.

97. The medical implant according to claim 96, characterized in that, The inscribed circle diameter of the at least 10 holes is at most 1 µm.

98. The medical implant according to claim 8, characterized in that, The inscribed circle diameter of the at least five holes is greater than 10 µm.

99. The medical implant according to claim 98, characterized in that, The inscribed circle of the at least five holes is at least 15 µm.

100. The medical implant according to claim 99, characterized in that, The inscribed circle of the at least five holes is at least 20 µm.

101. The medical implant according to claim 100, characterized in that, The inscribed circle of the at least five holes is at least 25 µm.

102. The medical implant according to claim 101, characterized in that, The inscribed circle of the at least five holes is at least 30 µm.

103. The medical implant according to claim 102, characterized in that, The inscribed circle of the at least five holes is at least 40 µm.

104. The medical implant according to claim 103, characterized in that, The inscribed circle of the at least five holes is at least 50 µm.

105. The medical implant according to claim 104, characterized in that, The inscribed circle of the at least five holes is at least 60 µm.

106. The medical implant according to claim 15, characterized in that, The maximum Shore hardness of the fiber material in the functional layer (4) is 80A.

107. The medical implant according to claim 106, characterized in that, The maximum Shore hardness of the fiber material in the functional layer (4) is 70A.

108. The medical implant according to claim 107, characterized in that, The maximum Shore hardness of the fiber material in the functional layer (4) is 60A.

109. The medical implant according to claim 108, characterized in that, The maximum Shore hardness of the fiber material in the functional layer (4) is 50A.

110. The medical implant according to claim 15, characterized in that, The material of the fiber in the support layer (3) has a Shore hardness of at least 100A.

111. The medical implant according to claim 110, characterized in that, The material of the fiber in the support layer (3) has a Shore hardness of at least 60D.

112. The medical implant according to claim 111, characterized in that, The material of the fiber in the support layer (3) has a Shore hardness of at least 70D.

113. The medical implant according to claim 112, characterized in that, The material of the fiber in the support layer (3) has a Shore hardness of at least 80D.

114. The medical implant according to claim 20, characterized in that, The functional layer (4) and the support layer (3) are respectively made of thermoplastic polyurethane or formed of thermoplastic polyurethane.

115. The medical implant according to claim 50, characterized in that, The total thickness of the membrane (2) is a maximum of 30% of the height of the grid element.

116. The medical implant according to claim 115, characterized in that, The total thickness of the membrane (2) is a maximum of 20% of the height of the grid element.

117. The medical implant according to claim 116, characterized in that, The total thickness of the membrane (2) is a maximum of 10% of the height of the grid element.

118. The medical implant according to claim 51, characterized in that, The height of the grid element is between 40 µm and 150 µm.

119. The medical implant according to claim 118, characterized in that, The height of the grid element is between 40 µm and 130 µm.

120. The medical implant according to claim 119, characterized in that, The height of the grid element is between 40 µm and 110 µm.

121. The medical implant according to claim 120, characterized in that, The height of the grid element is between 40 µm and 100 µm.

122. The medical implant according to claim 121, characterized in that, The height of the grid element is between 50 µm and 90 µm.

123. The medical implant according to claim 122, characterized in that, The height of the grid element is between 50 µm and 80 µm.

124. The medical implant according to claim 52, characterized in that, The ratio between the thickness of the membrane (2) and the height of the grid element is at most 1 / 4.

125. The medical implant according to claim 124, characterized in that, The ratio between the thickness of the membrane (2) and the height of the grid element is at most 1 / 5.

126. The medical implant according to claim 125, characterized in that, The ratio between the thickness of the membrane (2) and the height of the grid element is at most 1 / 8.

127. The medical implant according to claim 126, characterized in that, The ratio between the thickness of the membrane (2) and the height of the grid element is at most 1 / 10.

128. The medical implant according to claim 127, characterized in that, The maximum ratio between the thickness of the membrane (2) and the height of the grid element is 1 / 12.

129. The medical implant according to claim 128, characterized in that, The ratio between the thickness of the membrane (2) and the height of the grid element is at most 1 / 15.

130. The medical implant according to claim 129, characterized in that, The ratio between the thickness of the membrane (2) and the height of the grid element is at most 1 / 20.

131. The medical implant according to any one of claims 50 and 115-130, characterized in that, The height of the grid element is the height of the connecting strip (12) or the wire.

132. The medical implant according to claim 51, characterized in that, The height of the grid element is the height of the connecting strip (12) or the wire.

133. The medical implant according to claim 52, characterized in that, The height of the grid element is the height of the connecting strip (12) or the wire.

134. A method for manufacturing a medical implant according to any one of claims 1-133, the method comprising the following steps: a. Provide the support structure (1); b. Apply the functional layer (4) to the support structure; c. Perforating the functional layer (4) by laser cutting or solvent spraying; and d. Apply the support layer (3) to the functional layer (4).

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