Implants for treating aneurysms

Abstract

The invention relates to an implant (1) for treating arteriovenous malformations, in particular aneurysms (2), wherein the implant (1) can be brought to a target site in the patient's vascular system in a compressed state via a microcatheter (3), and the implant (1) is given a second structure by which it adopts an expanded state when released from the microcatheter (3), wherein the implant (1) is detachably connected to an insertion aid (5) via a detachment site (4), and wherein the implant (1) in the expanded state has a body (6), the body (6) having a proximal section (7) and a distal section (8), wherein the proximal section (7) and the distal section (8) have a dome-shaped configuration, wherein the convex side of the dome of the proximal section (7) faces in the proximal direction and the convex side of the dome of the distal section (8) faces in the distal direction, and wherein the proximal section (7) and the distal section (8) are connected to each other by a plurality of connecting struts (9). Alternatively, the implant (1) can have the shape of a closed tulip flower head. The implant (1) according to the invention can effectively adapt to the shape of a corresponding aneurysm (2).

Description

[0001] The present invention relates to an implant for treating arteriovenous malformations, particularly aneurysms, which implant can be navigated in a compressed state to a destination in a patient's vascular system through a microcatheter and is preset to a second configuration that causes the implant to assume an expanded state when released from the microcatheter, wherein the implant is detachably connected to an insertion aid via a cut or separation point.

[0002] Aneurysms are typically saccular or fusiform dilations of the blood vessel wall, primarily arising in structurally weak areas of the vessel wall due to the constant pressure of blood. Consequently, the inner vessel wall of an aneurysm is sensitive and easily damaged. Rupture of an aneurysm often leads to severe health consequences and, in the case of cerebral aneurysms, neurological impairment or even death.

[0003] In addition to surgical interventions, in which the aneurysm is clamped, for example, by means of a clip, endovascular methods are particularly known for treating aneurysms, which primarily employ two measures. One option involves filling the aneurysm with an occluding device, in particular using so-called coils (platinum spirals). The coils promote the formation of a thrombus, thereby ensuring the occlusion of the aneurysm. On the other hand, it is known to block the path to the aneurysm, for example the neck of a berry aneurysm, from the vessel side by using a stent-like implant and thereby disconnect it from the blood flow. Both methods serve to reduce the blood flow into the aneurysm and, in this way, to reduce, ideally even eliminate, the pressure acting on the aneurysm and thus reduce the risk of aneurysm rupture.

[0004] When filling an aneurysm with coils, it may happen that the aneurysm is not filled enough, allowing blood to flow into the aneurysm and thus causing the pressure on its inner wall to continue. The risk of the aneurysm continuing to expand and eventually rupturing remains, although in a weakened form. In addition, this treatment method is only suitable for aneurysms with a relatively narrow neck - so-called berry aneurysms - otherwise there is a risk that the coils will protrude from the wider aneurysm neck into the blood vessel (where they will cause a clot), which can lead to an occlusion in the blood vessel. In the worst case, the coils can be completely flushed out of the aneurysm and cause the blood vessel to be occluded at another location. In order to keep the coils in place in the aneurysm sac, the aneurysm neck is often additionally covered with a special stent.

[0005] Another type of endovascular treatment has focused on so-called flow diverters. These implants are similar in appearance to stents used to treat stenosis. However, because the purpose of flow diverters is not to maintain blood flow but to block the blood vessel proximal to the aneurysm, their mesh size is very narrow; alternatively, such implants are coated with a membrane. A drawback of these implants is the risk that outflow branches immediately adjacent to the treated aneurysm may also be covered and, therefore, closed in the medium to long term.

[0006] WO2012 / 034135A1 discloses an implant comprising first and second parts that are arranged one behind the other within a catheter but, upon release within an aneurysm, assume a three-dimensional, nearly spherical shape and thereby fill the aneurysm. The basic material of the three-dimensional implant is a mesh fabric, and the embodiments and figures are based on a tubular braid composed of shape-memory material. A disadvantage of this prior art example has been found to be its unfavorable stiffness. Since aneurysms are rarely perfectly round, the three-dimensional implant must be able to adapt to the aneurysm's morphology in the best possible manner. Furthermore, the implant is too bulky for low-caliber catheters.

[0007] Another implant for insertion into an aneurysm is disclosed in WO 2017 / 089451 A1. The implant described therein comprises several subunits, each with a framework of struts, with a covering arranged between them. However, the implant must first be formed into multiple coils within the aneurysm until sufficient coverage of the aneurysm surface is achieved.

[0008] WO 2009 / 135166 A2 discloses an implant for aneurysms. The implant has a barrel-like shape and is composed of multiple interwoven filaments that converge centrally at a point at both the proximal and distal ends. This implant allows for the occlusion of an aneurysm using a single implant. However, blood flow can cause the barrel-shaped structure to be compressed, reducing the overall volume of the implant. This can lead to incomplete filling of the aneurysm.

[0009] Generally speaking, the problem arises from the desire to have an implant that can fill an aneurysm individually. However, it must be kept in mind that aneurysms are often irregularly shaped and vary in size, so a single implant must be able to effectively adapt to these diverse shapes. Precisely because of this problem, conventional coils are still frequently used, as they largely fill the aneurysm's space independently and can become entangled during the process. The attending physician adjusts the number of coils inserted according to the size of the aneurysm.

[0010] Starting from the above-mentioned prior art, the object of the present invention is therefore to provide an implant which, as a single implant or in combination with other occluding devices, is able to fill an aneurysm while adapting to the shape and size of the aneurysm interior.

[0011] According to a first embodiment, the object is achieved by the proposed invention, which provides an implant for treating arteriovenous malformations, in particular aneurysms, wherein the implant can be brought to a target location in the patient's vascular system in a compressed state by a microcatheter, and the implant is preset to a second structure, which second structure causes the implant to assume an expanded state when released from the microcatheter, wherein the implant is detachably connected to an insertion aid at a separation point, and wherein the implant in the expanded state has a base comprising a proximal segment and a distal segment, the proximal segment and the distal segment being dome-shaped, the convex side of the dome of the proximal segment facing in the proximal direction, and the convex side of the dome of the distal segment facing in the distal direction, and wherein the proximal segment and the distal segment are connected to each other by a plurality of connecting struts.

[0012] Due to the fact that the implant has distal and proximal domes and connecting struts extending between them, it offers a high degree of flexibility. This is ensured in both the axial and radial directions, that is, the implant can adapt to the available space in the longitudinal direction and also in the rotational direction around the longitudinal axis. In the expanded state, the implant may be slightly larger than the interior of the aneurysm, but the flexibility created by the connecting struts extending longitudinally between the distal and proximal domes enables the implant to adapt effectively. For example, the connecting struts can be slightly compressed or twisted to achieve axial or radial adaptation, respectively. Since the implant is usually slightly oversized compared to the size of the aneurysm to be treated, the implant will anchor itself in the aneurysm. In this case, the connecting struts are used to achieve length compensation and adaptation to the aneurysm. Due to the spring effect, good anchoring is achieved.

[0013] The longitudinal direction is to be understood as a direction corresponding to or parallel to the axis extending from the proximal to the distal side, and connecting struts extending in the longitudinal direction are also to be understood to include those having a longitudinal component but not extending in a straight line in the longitudinal direction. In fact, it is advantageous if the connecting struts present between the proximal and distal segments are curved, as this ensures flexibility in terms of length. By adopting a straighter configuration, the connecting struts can stretch slightly, but they can also be compressed together if the curvature increases. In this way, the connecting struts exert a certain spring action in both the axial and radial directions. The spring effect improves the anchoring of the implant in the aneurysm. A curved extension is to be understood as a configuration of connecting struts having one or more curved sections.

[0014] In the longitudinal direction, the individual connecting struts extend substantially parallel, meaning they do not intersect and typically do not intertwine, allowing them to compress or stretch independently of one another. Similarly, rotational movement of the distal segment relative to the proximal segment about the longitudinal axis is possible, meaning the connecting struts also ensure radial flexibility. As proposed by the present invention, a substantially parallel configuration of the connecting struts in the longitudinal direction is also possible if the bending lines of the individual connecting struts extend differently.

[0015] The terms "proximal" and "distal" are to be understood in such a way that the part facing the attending physician when the implant is inserted is referred to as the proximal side, and the part facing away from the attending physician is referred to as the distal side. Typically, the implant is thus moved forward in the distal direction by the microcatheter. For example, the microcatheter can be a microcatheter with an inner diameter of 0.021", 0.027" or 0.033". The term "axial" refers to the longitudinal axis of the implant, which extends from the proximal side to the distal side when the implant is in the extended position, and "radial" refers to a direction orthogonal thereto.

[0016] The dome-shaped proximal and distal ends of the base body can also be described as plate-shaped. To better adapt to the shape of the aneurysm, the segments arranged in the end regions are typically slightly rounded toward their respective ends. Furthermore, a rounded shape is particularly atraumatic. The convex curvature of the dome or plate thus points toward the distal or proximal end of the base body, while the concave curvature points toward the interior of the base body. Depending on the situation, the proximal and distal segments can also be beveled rather than rounded, in which case the relatively flat ends are generally considered to be the convex sides. However, the proximal plate, in particular, need not be completely round; it typically has a rounded portion, but it also has a central extension in the proximal direction, where it terminates toward the separation point. The diameters of the distal and proximal segments in the expanded state are variable and can be adjusted to suit individual aneurysm sizes and neck dimensions. The implant is typically designed so that during free expansion, it assumes a larger diameter than the aneurysm's interior. This ensures that the implant secures itself within the aneurysm in a positively sealed manner.

[0017] Conveniently, the proximal segment and / or the distal segment are composed of framework struts that are at least partially connected to each other. These framework struts can form a mesh or ring structure in the proximal segment and / or the distal segment. The framework struts therefore intersect at certain intersections, thereby creating gaps between the framework struts. These gaps or meshes / rings can have different shapes, and for example, can be honeycomb, diamond or flower-shaped, with rounded edges. The advantage provided by circular shapes is that they are particularly non-traumatic. However, the gaps / voids do not have to be completely surrounded by struts; for example, these rings can rather be provided with an opening on one side, which will further increase the flexibility of the segment. Observed from the distal or proximal side, the implant can, for example, have 3 to 8 rings arranged in a circle.

[0018] In terms of its main structure, the implant's base is preferably composed essentially of framework struts forming the proximal and distal segments and connecting struts connecting the proximal and distal segments to each other. The design of the struts ensures that the implant can be easily folded and unfolded for placement in or release from the microcatheter.

[0019] Connecting struts connect the proximal and distal segments. The total number of connecting struts can be, for example, 3 to 10, in particular 6 to 8. The connection points between the connecting struts and the distal or proximal segments, which are usually composed of frame struts, can be arranged in various ways and, for example, can be arranged in one plane, but can also be offset from one another. The length and shape of the connecting struts can also be the same, but can also be different. For example, in the case of staggered connection points, it may also be necessary to arrange connecting struts of different lengths. Different cross-sections can also be selected for the connecting struts, depending on the desired use.

[0020] In particular, the struts of the implant (framework struts and connecting struts) can be produced by laser cutting technology. However, it is also feasible to provide the matrix with a braided structure in which the individual struts are interwoven or woven together. Other manufacturing processes, such as electroplating or photolithographic production, three-dimensional printing or rapid prototyping, can also be used. The struts provided can have a circular, oval, square or rectangular cross section, in the case of a square or rectangular cross section, the edges can have a rounded configuration. The individual struts can also consist of several individual filaments, which are twisted together or extend in parallel.

[0021] Conveniently, the distal segment can include an area without framework struts, which is expandable and compressible. This area is preferably located centrally in the distal segment so that it is roughly arranged at the distal end of the matrix. In the case of a preferred mesh / ring structure, an opening is therefore created in the distal segment between the meshes / rings. This area causes the size of the distal segment to be adapted to the requirements within the aneurysm, in particular with respect to the circumference. In order to meet specific application requirements, different sizes and different numbers of meshes / rings can be selected. As determined by the size and shape of the aneurysm, the distal segment can be expanded or compressed to a greater or lesser extent, achieving flexibility by the (central) area without framework struts. This area therefore produces a certain amount of elasticity or spring effect.

[0022] It is particularly preferred to provide the proximal segment with a membrane that at least partially covers the proximal segment, the membrane thus covering the aneurysm neck and largely preventing blood from flowing into the aneurysm. By isolating the aneurysm from the blood flow, it will eventually shrink / regress and the risk of aneurysm rupture is eliminated, wherein the membrane thus has a blood flow regulating effect.

[0023] The membrane need not be limited to the proximal segment; it can also be provided on the distal segment, and / or the connecting struts can also be provided with membranes. If there are areas in the distal segment where the framework struts are not arranged as described above, these areas should also be free of membranes. The placement of additional membranes enhances the blood flow-regulating effect of the membrane(s). Furthermore, the risk associated with endoleaks—i.e., blood inflow through leaks between the implant and the aneurysm sac—is further reduced.

[0024] According to a second embodiment, the present invention relates to an implant for treating arteriovenous malformations, in particular aneurysms, which, in a compressed state, can be navigated via a microcatheter to a destination in the patient's vascular system and which is pre-configured in a second configuration, which, upon release from the microcatheter, causes the implant to assume an expanded state. The implant is detachably connected to an insertion aid via a cut-off or separation point and, in the expanded state, comprises a base body consisting of struts that are at least partially interconnected at intersections, thereby creating interspaces between the struts. In the expanded state, the struts extend radially outward at the proximal end of the base body and, further in the distal direction, axially and radially inward, thereby creating a bulge in the base body. The base body has a region at the distal end in which the struts are not connected to one another. In the expanded state, the base body may, in particular, have an opening at the distal end.

[0025] According to this second embodiment, the expanded base has the shape of a closed tulip flower. The struts converge proximally at a separation point. From this separation point, the struts initially extend radially outward, then further distally while reapproaching the central longitudinal axis. In some cases, the struts may also extend proximally during their radially outward extension, resulting in an overall inward curvature of the base at the proximal end. The struts are at least partially interconnected, creating a space or mesh between the edges of the struts. This space or mesh can have various shapes, such as honeycomb, heart, leaf, or diamond, with the edges of the space / mesh typically being rounded. The interconnected struts can form segments similar to tulip petals: several petal-like segments emanate from the proximal end of the base and form the outer surface of the base, which abut the inner wall of the aneurysm. These segments converge at the proximal end of the base. In this way, a base is created in which the individual segments are flexible and movable, allowing them to adapt well to the shape of the aneurysm, thereby enabling atraumatic implantation. The elastic distal ends of the struts / segments serve as support to push the proximal end of the base into the aneurysm neck, thereby promoting a good seal of the aneurysm from the blood flow.

[0026] At the distal end, the struts are not connected to each other, so the matrix is ​​open here. However, the struts or segments formed by the struts can overlap at the distal end so that the opening is actually closed, but the opening at the distal end can remain if each strut / segment ends distally in front of the opening.

[0027] Typically, the matrix is ​​largely tailored to the shape of the aneurysm. That is, the struts initially extend radially outward toward the aneurysm wall and then continue distally along it, forming a radially inward curve. Therefore, the exact shape the matrix forms within the aneurysm also depends on the aneurysm's shape. Whether the opening remains at the distal end of the matrix or whether the struts overlap also depends on the aneurysm's shape. In the case of aneurysms that are relatively small relative to the body, the struts can, for example, be compressed to a point where their distal ends overlap and the opening disappears, while in larger aneurysms, the distal opening can be retained. In the expanded state, the implant may be slightly larger than the interior of the aneurysm, but the flexibility created by the struts allows the implant to effectively adapt. Because the implant is typically slightly oversized compared to the size of the aneurysm being treated, it secures itself within the aneurysm. The matrix's shape resembles a closed tulip flower, but can also be described as an upset spherical or ellipsoidal shape, although this is understood to mean not only a precise geometric shape but also a shape that at least approximates the relevant geometry. Typically, an expanded base that is flattened proximally or has a central inward indentation can be used to prevent portions of the implant from extending beyond the aneurysm and into the parent vessel.

[0028] With regard to the pillars of the second embodiment of the invention, what has been said with regard to the first embodiment applies, i.e. the pillars of the implant can be produced in particular by laser cutting technology, but it is also feasible for them to have a matrix in the form of a braided structure, comprising individual pillars that are braided or woven together. Other manufacturing processes can also be used, such as electroplating or photolithographic production, three-dimensional printing or rapid prototyping. The pillars provided can have a circular, oval, square or rectangular cross-section, in the case of a square or rectangular cross-section, the edges can have a rounded configuration. The individual pillars can also consist of several individual filaments that are twisted together or extend in parallel.

[0029] Similarly, according to a second embodiment, one or more membranes can be provided covering the substrate. It is particularly preferred to provide a membrane that at least partially covers the proximal region of the substrate. Consequently, the membrane covers the neck of the aneurysm and largely prevents blood from flowing into the aneurysm. Disconnecting the aneurysm from the blood flow leads to its eventual shrinkage / degeneration and eliminates the risk of aneurysm rupture, thereby providing a blood flow-regulating effect.

[0030] The membrane need not be limited to the proximal region of the base; the distal region can also be provided with a membrane. However, if the distal ends of the struts do not overlap significantly, the distal ends with openings are typically free of membrane. By providing the membrane in additional regions of the base, the blood flow regulating effect of the membrane(s) is enhanced. Furthermore, the risk associated with endoleaks—i.e., blood inflow through leaks between the implant and the aneurysm sac—is further reduced.

[0031] Regardless of the embodiment, the implant is preferably made at least partially of a shape-memory material. This allows the implant to be pre-programmed with a desired secondary configuration, which it automatically adopts upon exiting the microcatheter. Shape-memory metals are particularly well known in the field of medical engineering, with nickel-titanium alloys, such as those used under the name Nitinol, being particularly noteworthy in this regard. Typically, the secondary configuration arises upon exiting the microcatheter due to the removal of the external constraints imposed by the microcatheter; however, it is also possible that the secondary configuration is formed due to temperature changes that occur upon exiting the microcatheter.

[0032] The implant is detachably connected to an insertion aid via a separation / cut-off point. The insertion aid can be a conventional push wire for advancing the implant through the vascular system to the desired position. However, an insertion aid of tubular or hose-shaped design and having a lumen is particularly preferred. With the help of such an insertion aid, after the matrix has been inserted into the aneurysm and expanded there, further occluding devices can be inserted into the interior of the aneurysm and / or the matrix, whereby further occlusion of the aneurysm can be achieved. It is also conceivable to use the insertion aid to introduce other filling materials into the aneurysm, which are known from the prior art, such as adhesive embolic substances, for example onyx.

[0033] Additional filling with other occluding devices or materials is advantageous because it prevents compression (compaction) of the implant by external forces. In practice, an aneurysm may act from the outside on an inserted implant that is hollow inside, causing the implant to be compressed and no longer able to completely fill the aneurysm, or to partially squeeze out the aneurysm, which can lead to obstruction of blood flow in the parent vessel. This is prevented by additional filling of the implant interior with an occluding device or material introduced via a tubular or hose-shaped insertion aid.

[0034] Furthermore, an additionally inserted occluding device can fill the gap between the outside of the implant and the inner wall of the aneurysm. This is particularly important when treating aneurysms of irregular shape. In order to allow an additionally introduced occluding device, in particular a conventional occluding coil, to enter the space between the outside of the implant and the inner wall of the aneurysm, the distal segment or distal region of the base body should not be covered by a membrane; on the contrary, if a membrane is provided, it should be restricted to the proximal segment or proximal region. It is considered particularly advantageous that the tubular or hose-shaped insertion aid terminates approximately in the middle in the latter when the base body is expanded, which enables the occluding device introduced via the insertion aid to migrate outwards from there and pass through the gaps between the struts into the area between the implant and the aneurysm.

[0035] If the insertion aid has a lumen, the insertion of further occluding devices or occluding materials is significantly simplified. In the case of implants provided with a membrane, there is in fact the problem of exploratory ability, i.e. testing how further occluding devices or materials can be introduced into the aneurysm in order to achieve a seal that is as complete as possible to prevent blood from flowing into the parent vessel. If a subsequent insertion is performed, it may be necessary to introduce another catheter and pierce the membrane of the implant. As proposed by the present invention, this is significantly simplified because the insertion of the occluding device or material can already be completed during the implantation of the implant. Preferably, the implant is first expanded in the aneurysm, but not yet separated. The occluding device is then introduced by means of a tubular or hose-shaped insertion aid. Finally, separation and final release of the implant occur so that the insertion aid and the microcatheter can be withdrawn in the proximal direction.

[0036] An insertion aid provided with an internal cavity can be realized in a variety of ways, but of course sufficient flexibility should be provided to allow the insertion aid to navigate through narrow-lumen blood vessels, especially those present in the cranium. For example, the insertion aid can be a catheter-type design, i.e. it can consist of a braid of metal and / or plastic material. However, the insertion aid can also be designed as a tubular hypotube. For example, the tube can be made of a flexible polymer material or a metal helical structure, and in the case of a metal helical structure, multiple layers can be provided, typically up to 4 layers, preferably 2 layers. Thus, these layers form a hollow structure consisting of one or more spirals. In the case of a multilayer metal helical structure, the helical structure configurations of two adjacent layers are preferably opposite, i.e. the right helical structure is located above the left helical structure, and vice versa. The helical structures are therefore twisted in opposite directions. It is considered useful to provide several layers of opposite construction so that the tube can transmit torsional motion from the proximal side to the distal side.

[0037] Where the tube is manufactured from a polymeric material, slits may be provided in the tube to further increase the flexibility of the hose.

[0038] For linear and tubular or hose-shaped insertion aids, it is advantageous if their flexibility increases from proximal to distal. This ensures that, on the one hand, the insertion aid is sufficiently rigid in the proximal region to allow propulsion and the transmission of torsional forces, but, on the other hand, is sufficiently flexible in the distal region to enable navigation through narrow vessels. For example, the diameter can decrease from proximal to distal, and this decrease can occur gradually or in one or more steps.

[0039] The insertion aid can also be constructed from a plurality of components. In particular, in the case of a tubular or hose-shaped insertion aid, the proximal region can be designed as a tubular hypotube, and the distal region can be designed as a flexible catheter.

[0040] Regardless of the insertion aid's construction, it is brought to the target location via a microcatheter. This also applies if the insertion aid itself is designed like a catheter. Furthermore, an external friction-reducing coating of the insertion aid, for example using PTFE (polytetrafluoroethylene, Teflon), is considered advantageous.

[0041] The separation of the implant from the insertion aid is carried out electrolytically, thermally, mechanically or chemically. The electrolytic separation method provides that the separation point is electrolytically corroded by applying a voltage, resulting in the implant being disconnected from the insertion aid. To avoid anodic oxidation of the implant, it should be electrically isolated from the separation point and the insertion aid. The electrolytic separation of implants is a well-known practice in the prior art, in particular for coils for closing aneurysms. For example, relevant cut-off / separation points are described in the publication WO 2011 / 147567 A1. The principle is based on the fact that, when a voltage is applied, suitably designed separation points made of a suitable material, in particular a metal, are generally dissolved by anodic oxidation at least to such an extent that the region of the implant located distal to the respective separation point is released. The cut-off points can be made of, for example, stainless steel, magnesium, a magnesium alloy or a cobalt-chromium alloy. Particularly preferred magnesium alloys are It was developed by MeKo from Sarstedt / Germany (see WO 2013 / 024125 A1). It is an alloy consisting of magnesium and, in particular, lanthanides, especially dysprosium. Another advantage of using magnesium and magnesium alloys is that magnesium residues remaining in the body are physiologically harmless.

[0042] The dissolution of the separation point is induced by applying a voltage. This can be an alternating current or a direct current, with low current strengths (<3 mA) being sufficient. In this case, the separation point generally acts as an anode, its metal being oxidized and dissolved. It is important that the separation point is electrically connected to the voltage source, in particular via an insertion aid. For this purpose, the insertion aid itself must also be of electrically conductive design. Due to the fact that the corrosion-inducing current is influenced by the surface of the cathode, the cathode surface should be significantly larger than the surface of the anode. To a certain extent, the speed of the separation point dissolution can be controlled by appropriately determining the size of the cathode surface relative to the anode surface. Therefore, the present invention also relates to a device comprising a power source and, where applicable or appropriate, electrodes to be placed on the body surface.

[0043] In particular, the separation point can have the form of a separation element, which is arranged on the outside of the insertion aid and is connected to the proximal end of the base body. The application of voltage causes the connection between the separation element and the base body to corrode to such an extent that separation / cutting and release of the implant is achieved. Preferably, the separation element is arranged annularly around the insertion aid so that the element can form a disk with a central hole through which the insertion aid can be passed. One or more separation wires can be attached to the separation element, the wires advantageously having insulation so as to allow the voltage to be applied to the separation point in a manner that is as concentrated as possible. The separation wire(s) can be routed outside the insertion aid or through the interior of the insertion aid. If the insertion aid is made of metal, in particular in the case where it has a catheter-like design comprising a metal braid, the current can also be supplied through the metal braid.

[0044] As already mentioned, it is advantageous if the insertion aid projects into the base body in the expanded state. In particular, a tubular or hose-shaped insertion aid can extend distally beyond the separation point. In the embodiment described above in which a separation element is provided which surrounds the insertion aid in an annular manner, the separation element is therefore positioned closer to the distal side of the insertion aid. Thus, the base body can first be introduced into the aneurysm and expanded by withdrawing the microcatheter. Further occluding devices, in particular coils, can then be introduced into the interior of the base body via the insertion aid which projects into the base body. Once this process is complete, implant separation occurs and the microcatheter and insertion aid can finally be retrieved and removed from the vascular system.

[0045] In the case of mechanical separation / severance, there is usually a form-locked, force-locked or friction-fit connection, which is destroyed when the implant is released, resulting in separation of the implant from the insertion aid. One option is to provide a radial protrusion in the distal region outside the insertion aid, which protrudes into the implant. The microcatheter is positioned around the insertion aid. In this way, a friction-fit connection is established between the insertion aid, the proximal end of the implant and the microcatheter. When the microcatheter is retracted in the proximal direction relative to the implant and the insertion aid, the external contraction caused by the microcatheter is eliminated, causing the proximal end of the implant to expand radially and disengage from the protrusion, i.e., a friction-fit disengagement.

[0046] In this context, the distal region of the insertion aid is understood to be the region situated more distally that interacts with the implant, but it is not necessarily the distal end of the insertion aid, which typically extends even further into the implant to enable placement of an occluding device there. Radial projections are those that project outwards in the radial direction, i.e. perpendicularly to the longitudinal axis of the insertion aid.

[0047] The external constraint preventing proximal expansion cannot always be caused by the microcatheter; an additional sheath can also be provided around the distal end of the insertion aid, which presses the proximal end of the implant onto the insertion aid. To enable release, this sheath must of course also be retractable in the proximal direction relative to the insertion aid and the implant.

[0048] The radial projections can be made of an elastic material, in particular an elastomeric material. The proximal end of the implant is pressed against the insertion aid by the microcatheter or sheath and is virtually clamped in place, thereby achieving a friction-fit connection. In particular, the projections can be shaped as pads. These pads can be annularly surrounding the insertion aid, with several radially extending rings or spiral structures being provided for particularly secure fastening.

[0049] The proximal end of the implant can also be provided with a thickened portion, which is held, for example, between the radial projections of the insertion aid. For example, the thickened portion can be spherical or have a similar geometric form. In this case, the fixation of the implant to the insertion aid is a combination of a friction fit and a positive fit.

[0050] In order to allow the attending physician to visualize the separation, radiopaque markers located in the region where the implant is attached to the insertion aid are advantageous. For example, the proximal end of the insertion aid, the microcatheter, and / or the implant, or a sheath surrounding the insertion aid, may be provided with radiopaque markers in this region whose movement, in particular relative to one another, may be observed radiographically.

[0051] It is also possible to provide a purely form-locking fastening method. In this regard, a separation element can be arranged at the proximal end of the implant, which element engages in a form-locked manner in a recess provided for this purpose in a tubular or hose-shaped insertion aid. Due to the fact that the insertion aid is surrounded by the microcatheter or another sheath, the separation element is prevented from expanding radially and leaving the recess. As long as the microcatheter or sheath is not retracted in the proximal direction, this ensures that the separation element remains firmly in the recess. Only when the microcatheter / sheath moves toward the proximal end and no longer covers the recess can the separation element leave the recess, resulting in separation and ultimately releasing the implant. The recess in the insertion aid can surround the entire wall of the insertion aid, or simply be recessed into the wall as a depression.

[0052] According to another variant, one or more separation elements extend proximally at the proximal end of the implant and are held in place in a form-locked manner by one or more retaining elements arranged on the insertion aid. The retaining elements are made of a material with shape memory properties, wherein the retaining elements are pre-set to assume a second configuration that they strive to assume but are prevented from assuming as long as the microcatheter or a separate sheath surrounds the retaining element. External constraints can in particular prevent the retaining element from assuming the second configuration; however, after the microcatheter / sheath has been retracted, the retaining element may also experience temperature changes that cause it to assume its second configuration. When assuming its second configuration, the retaining elements open and release the separation elements, i.e., causing the implant to separate.

[0053] For example, in this embodiment, the separation element can be spherical, and the retaining element can surround the separation element in a shell-like manner. When the shell-shaped retaining element expands, the spherical separation element can be withdrawn. Separation can be achieved with a single separation element interacting with a single retaining element, but it is also possible to combine multiple retaining elements with the associated separation element, preferably along the circumference of the insertion aid, to ensure uniform release over the entire circumference.

[0054] Regardless of whether electrolytic or mechanical separation is involved, the proximal end of the implant retained at the separation point can be provided in particular in the form of a proximal wire, the connection of which to the separation element / separation point is released for the purpose of disconnecting the implant. In particular in the case of mechanical separation, a further separation element can be attached to the proximal wire secured by the insertion aid.

[0055] Another option is to design the separation point as a thermal separation point. In the case of a thermal separation point, the connection between longitudinally adjacent parts of the implant can be destroyed by heating the separation point, causing it to soften or melt, thereby achieving separation. Another option is to utilize chemical severance in such a way that the separation is caused by a chemical reaction occurring at the separation point.

[0056] Different types of separation can also be combined, for example electrolytic and mechanical separation. For this purpose, a mechanical connection, in particular a positive fit, is established between the elements and remains in place until the elements maintaining the mechanical connection are electrolytically corroded.

[0057] Regarding the combination of electrolytic and mechanical separation, one option is to provide an insertion aid end piece at the distal end of the insertion aid, said end piece having an electrolytically corrodible separation point, with the insertion aid end piece being connected to the implant end piece at the proximal end of the implant via an insulating element. In particular, a positive-locking connection can exist between the insertion aid end piece, the insulating element, and the implant end piece to ensure a secure attachment between the insertion aid and the implant during advancement through the microcatheter. Furthermore, the positive-locking connection can ensure that torsional movements are properly transmitted.

[0058] The insertion aid end piece is preferably made at least partially of a metal that ensures the electrical conductivity of the separation point, that is to say, an electric current can be applied to the insertion aid, which current is conducted to the separation point. In order to be able to apply an electric current to the separation point, it is also conceivable to provide a separate conductor that is insulated from the insertion aid itself. The separation point usually serves as an anode, so that the metal used for the separation point is oxidized and thus leads to dissolution of the separation point. The cathode is usually an electrode arranged on the surface of the patient's body; however, another electrical conductor can also be provided on or via the insertion aid to close the circuit acting on the separation point. Preferably, at least the separation point is made of a metal that dissolves well electrolytically or electroplatically, such as a cobalt-chromium alloy; however, other stainless steel metal alloys are also possible. Optionally, the separation point can be subjected to pre-corrosion to improve its dissolution properties.

[0059] In most cases, the implant endpieces are also made of metal. It is advantageous to manufacture the implant from a metal with shape memory properties, such as nickel-titanium alloys, or from a metal that dissolves relatively quickly in the body, such as magnesium. This allows the area of ​​the implant that is only needed for insertion, not permanently, to disappear over time. The more distal area of ​​the insertion aid endpiece, which remains in the body after detachment, can also be made of magnesium, for example. This allows unwanted foreign matter to dissolve.

[0060] An insulating element, arranged between the insertion aid and the implant end piece, insulates the implant from the applied voltage, thereby concentrating the current at the isolation point. The insulating element is made of an electrically insulating material. The form fit between the two end pieces is preferably achieved / transmitted via the insulating element.

[0061] According to a particularly preferred embodiment, both the insertion aid end piece and the implant end piece comprise a first short tubular element at which a narrow connecting web is arranged and which extends in the longitudinal direction towards a second short tubular element which is provided with an interruption / cutout on its circumference. Preferably, when viewed radially, the interruption / cutout is located opposite the connecting web. The insulating element is adapted to the two ends in such a way that the respective second tubular elements with their cutouts can each engage with a portion of the insulating element, the two portions of the insulating element being arranged one behind the other in the longitudinal direction. The two portions each provide space to accommodate the second tubular element. In this case, the longitudinal direction is understood to be a direction from the proximal side to the distal side and vice versa.

[0062] When the insertion aid end piece, the insulating end piece and the implant end piece are connected together, the second tubular element of the implant end piece is located proximal to the first tubular element, while the second tubular element of the insertion aid end piece is arranged distal to the first tubular element. The second tubular element of the implant end piece is engaged in the accommodation space of the portion of the insulating element that is positioned more proximally, while the second tubular element of the insertion aid end piece is engaged in the accommodation space of the portion of the insulating element that is arranged more distally. Therefore, the insertion aid end piece and the implant end piece are ultimately engaged with each other, but always through the interface layer formed by the insulating element. In the assembled structure, the second tubular element of the implant end piece is located proximal to the second tubular element of the insertion aid end piece. The interruption / cut in the second tubular element of the end piece is usually located in radially opposite positions.

[0063] The separation point is conveniently located in the region of a narrow connecting web of the insertion aid end piece, for example at the location where the connecting web of the insertion aid end piece is connected to the first continuous tubular element. The separation point can be easily corroded and dissolved by applying an electrical voltage, at least to such an extent that the region of the insertion aid end piece, i.e. the first tubular element, is separated from the rest of the separation element. In this case, the term separation element is to be understood as meaning the entirety of the insertion aid end piece, the insulating element and the implant end piece. The implant together with the implant end piece, the insulating element and the further distal region of the insertion aid end piece thus remains in the body, while the proximal region of the insertion aid end piece remains connected to the insertion aid and is removed from the body.

[0064] The described separation element—which combines a mechanical connection secured by form-locking with electrolytic detachability—is particularly advantageous in that the connection is mechanically secure, even when the insertion aid is proximally withdrawn. The mechanical connection persists even after the microcatheter has been pushed out or when it is withdrawn. Separation occurs only when a voltage is applied to the separation element, and in a well-controlled manner.

[0065] Basically, the separation element described above can also be used to insert any other implant. This is particularly true for the last-described embodiment, which involves a combination of electrolytic separation and mechanical connection and is therefore particularly safe to use. Therefore, the present invention includes a corresponding separation system even if the implant itself has a design that does not conform to the design and construction detailed in this patent application.

[0066] The separation point can be located proximal to the base body, but as described above, it is preferably provided within the base body or the implant, which results in the insertion aid extending into the implant in the expanded state. On the one hand, in the case of a tubular or hose-shaped design of the insertion aid, this makes it easier to insert further occluding devices, and on the other hand, the struts forming the proximal segment or proximal region can at least partially converge at the separation point, resulting in a slight inward inward bend in the proximal segment / region. Inward inward in the proximal and distal segments / regions is associated with the following advantages: traumatic support ends are excluded, or they cannot come into contact with the wall of the aneurysm because they are repositioned inside the base body.

[0067] Film-covered is understood to mean any arrangement of the respective struts or segments with a film, regardless of whether the film is applied to the outside or inside of the struts / segments, or whether the struts / segments are embedded in the film, the latter being preferred.

[0068] When the implant is provided with a membrane, it is able to isolate and occlude the aneurysm from the blood flow on its own, that is, no additional occluding device, such as a coil or the like, is required. The membrane provides sufficient elasticity so as not to hinder the folding and unfolding of the implant, and the membrane is not damaged in the process. A membrane arranged in the proximal section or region of the implant is particularly advantageous because, in this way, it forms a seal against the parent vessel. Usually, it is sufficient to insert only a single suitable implant into the aneurysm, but several implants proposed by the present invention can also be used. In addition, as mentioned above, an occluding device or occluding material can be placed in the implant. In this case, an insertion aid with a lumen is particularly advantageous. A stent or shunt can also be placed in the parent vessel.

[0069] However, embodiments of the invention are also conceivable in which it is provided that the matrix is ​​not equipped with a membrane. In this case, the implant generally serves as a support structure for holding other implants, such as coils, smaller-sized inventive implants with or without a membrane, or even other occlusive devices as described in the introduction. It is also conceivable to use the implant proposed by the invention in combination with other filling materials (as they are known in the prior art), such as adhesive embolic materials, such as onyx. Unless further occlusive devices or materials are already introduced when the implant is implanted, the implant is usually first inserted into the aneurysm, and then a microcatheter is inserted between the struts forming the implant and the occlusive or embolic agent is introduced into the aneurysm via the microcatheter.

[0070] When referring to membranes in the plural within the scope of the present invention, it is expressly noted that the individual membranes do not necessarily need to be separated from each other; rather, the individual membranes can be combined with one another to form a single membrane. Furthermore, a membrane, such as one covering the proximal segment or proximal region, can also consist of several individual membranes, each of which is designed, for example, to cover / fill a web / ring in the proximal segment.

[0071] Within the meaning of the present invention, a membrane is a thin structure with a flat surface, whether it is liquid-permeable, impermeable, or partially permeable. However, for the purpose of aneurysm treatment, a membrane that is completely or at least substantially impermeable to fluids such as blood is preferred. Furthermore, the membrane can also be designed to include an orifice through which an additional occluding device can be introduced. Another option is to design the membrane in such a way that it can be pierced by a microcatheter to introduce an additional occluding device, or even by the occluding device itself.

[0072] The membrane can be made of polymer fibers or films. Preferably, the membrane is produced using an electrospinning process. During this process, struts are typically embedded within the membrane. This can be achieved by spinning or weaving fibers around the struts, particularly the framework struts of the proximal and / or distal segments.

[0073] In electrostatic spinning, fibrils or fibers are separated from a polymer solution and deposited on a substrate by applying an electric current. The deposition causes the fibrils to condense into a nonwoven fabric. Typically, fibrils have a diameter in the range of 100 to 3000 nm. The membrane manufactured by electrostatic spinning has a very uniform texture. The membrane is tough and can withstand mechanical stress and can be mechanically pierced without an opening, thereby producing cracks propagated therefrom. Another advantage of electrospun membranes is that they can set up a large contact surface with blood. The thickness and porosity of the fibrils can be controlled by appropriately selecting process parameters. In the case of producing membranes and about materials suitable for this purpose, special attention is paid to the disclosure of WO 2008 / 049386 A1, DE 2806030 A1 and the literature referenced therein.

[0074] Instead of electrospinning, the membranes can also be produced by dipping or spraying processes such as spray coating. Regarding the material of the membranes, it is important that they are not damaged by the mechanical stresses generated when the implant is pulled into the microcatheter, deployed, unfolded, etc. To ensure this, the membranes should be sufficiently elastic.

[0075] The membrane can consist of a polymer material, such as polytetrafluoroethylene, polyester, polyamide, polyurethane or polyolefin. Particularly preferred are polycarbonate urethanes (PCU), in particular electrospun polycarbonate urethanes. In particular, an integral connection of the membrane to the pillars / segments is desirable. This integral connection can be achieved by providing covalent bonds between the membrane and the pillars / segments. The formation of covalent bonds is promoted by silanization of the pillars / segments, i.e. by chemical bonding of silicon, in particular silane, compounds to at least part of the surface of the pillars / segments. On the surface, silicon and silane compounds are attached, for example, to hydroxyl and carboxyl groups. Basically, in addition to silanization, other mediated adhesion methods between the pillars / segments and the membrane are also conceivable.

[0076] The silane compound in this case should be considered to follow the general formula R m SiX n All compounds in which m, n = 0-4, R represents an organic group, in particular an alkyl, alkenyl or aryl group, and X represents a hydrolyzable group, in particular OR, OH or halogen, in which R = alkyl, alkenyl or aryl group. In particular, silanes may have the general formula RSiX3. Furthermore, related compounds having multiple silicon atoms also belong to the group of silane compounds. In particular, silane derivatives in the form of organosilicon compounds are considered silane compounds in this context.

[0077] Other substances that promote thrombosis or endothelialization can be embedded in or deposited on the membrane. Substances that promote thrombosis are therefore advantageous because they support the formation of a thrombus or clot within the aneurysm, which ensures permanent occlusion of the aneurysm. An example in this regard is nylon filaments. Because aneurysms are caused by degenerative diseases of the blood vessel wall, particularly atherosclerosis, promoting endothelialization and correcting endothelial dysfunction may also have a beneficial effect. This is particularly applicable to areas where the aneurysm is in contact with the blood flow in the actual blood vessel (parent vessel). Preferably, substances that promote thrombosis are applied to the inside of the membrane, while substances that promote endothelialization are applied to the outside of the membrane, where the outside is understood to mean the side of the membrane facing the blood vessel wall in the implanted state, and the inside is understood to mean the side of the membrane facing the inside of the aneurysm. Examples of substances that promote thrombosis include collagen, while hyaluronic acid, statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) and other polymers can promote endothelial cell colonization. Polysaccharides that can mimic the glycocalyx, especially glycosaminoglycans, are particularly suitable polymers. Another material that can be used is POSS-PCU (polyhedral oligomeric silsesquioxane poly(carbonate-urea) urethane). It is a nanocomposite material that has been described as, among other applications, a scaffold for artificial organs and a coating for medical devices (Tan et al., Crit Rev. Biomed Eng. 2013; 41(6): 495-513). POSS-PCL (polyhedral oligomeric silsesquioxane poly(caprolactone-urea) urethane) can also be used. Suitable for both POSS-PCU and POSS-PCL, in particular functionalized derivatives of these nanocomposites can also be used. This is particularly applicable to those derivatives that can be obtained by linking with polyacrylic acid (poly-AA). Since POSS-PCU and / or POSS-PCL nanocomposite polymers are only less suitable for direct fixation on the implant surface, it has been found that it is advantageous to combine a polymer such as polyacrylic acid (poly-AA) with the nanocomposite material. This can be achieved, for example, by plasma polymerization of acrylic acid. The poly-AA-g-POSS-PCU surface obtained in this way promotes collagen binding (especially type 1 collagen) and thus promotes endothelial formation (see Solouk et al., Mater Sci Eng C Mater Biol Appl. 2015; 46: 400-408). Some additives, such as collagen or hyaluronic acid, are also advantageous because they can improve the friction against the inside of the catheter during advancement and the biocompatibility of the implant. Typically, a biofunctional or bioactive coating can be present on the membrane.

[0078] Preferably, the base body in the expanded state has an approximate spherical, ellipsoidal, oval, or cylindrical shape with an outwardly curved base. In particular, in the case of the second embodiment, the shape of the base body in the expanded state can also be described as a closed tulip flower. In this context, the geometric shape specified is understood to mean not only the exact shape, but also a shape that at least approximates the corresponding geometric shape. Basically, a spherical shape is well suited for filling regularly shaped aneurysms. However, when the implant is longitudinally compressed or stretched, the result is a shape that can be more accurately described as an ellipsoid or a cylinder with a convexly outwardly curved base region, depending on the degree of rounding / beveling of the proximal and distal domes and the longitudinal stretching / compression of the base body. In this case, the base region of the cylinder is considered to be the end face. Depending on the intended application, the diameter or length of the base body in the expanded state typically ranges from 4 to 25 mm. This diameter is sufficient to fill typical aneurysms, particularly those located in the intracranial region. The actual diameter created within the aneurysm can vary, allowing the implant to be used to treat aneurysms of varying sizes and aneurysms with varying sized aneurysm necks.

[0079] Conveniently, the implant is provided with one or more radiopaque markers, thereby allowing the attending physician to see the treatment. For example, these can include a spiral structure, a spiral or a rivet made of a radiopaque material, which is attached to the implant. As mentioned above, radiopaque markers on the microcatheter are also useful. The radiopaque markers can, for example, be composed of platinum, palladium, platinum-iridium, tantalum, gold, tungsten or other metals that do not transmit radiation. It is also feasible to provide the implant, in particular the struts of the substrate, with a coating consisting of a radiopaque material, such as a gold coating. For example, the coating can have a thickness of 1 to 6 μm. It is not necessary to apply a coating with a radiopaque material to the entire substrate. However, even when applying a radiopaque coating, it is considered useful to provide one or more radiopaque markers on the implant, in particular at the distal end of the implant.

[0080] Another measure for making the implant radiopaque could be to embed radiopaque substances in the membrane, for example heavy metal salts, such as barium sulfate. Such substances are known, for example, as contrast agents in X-ray technology.

[0081] Another option involves using struts made of a metal with shape memory properties, in particular a suitable nickel-titanium alloy that at least partially includes a platinum core. Such struts are known as DFT (Drawn Filled Tube) wires. Thus, the advantageous properties of nickel-titanium, namely imparting shape memory, are combined on the one hand with the advantageous properties provided by platinum, namely ensuring X-ray visibility, on the other.

[0082] The proposed invention provides an implant particularly suitable for the treatment of intracranial aneurysms, but its use in other types of aneurysms, such as aortic aneurysms or peripheral arterial aneurysms, is also contemplated, in which case the dimensions of the implant will be appropriately adjusted.

[0083] In addition to the implant itself, the present invention also relates to the use of the implant for treating arteriovenous malformations, in particular aneurysms. All statements made with respect to the implant itself also apply in an analogous manner to the use of the implant and the method for using the implant.

[0084] The present invention is further described by way of example with reference to the accompanying drawings. It should be noted that the drawings illustrate preferred embodiment variations of the present invention and that the present invention itself is not limited thereto. The present invention particularly includes any optional combination of the technical features described in the claims or in the specification as being relevant to the present invention, within the scope of technical convenience.

[0085] The invention is described in detail with reference to the following drawings, in which

[0086] Figure 1 shows a side view of the inventive implant in an aneurysm according to the first embodiment;

[0087] Figure 2 Shown in XX view from the far side Figure 1 The implant of the present invention;

[0088] Figure 3 is a side view of an inventive implant according to a first embodiment of the present invention, wherein the separation point is located near the base body;

[0089] Figure 4 is a side view of an inventive implant according to a first embodiment of the present invention, wherein the separation point is arranged inside the base body;

[0090] Figure 5 An implant according to a first embodiment is shown placed in an aneurysm, with a membrane covering the proximal segment;

[0091] Figure 6 An implant placed in an aneurysm according to a first embodiment is shown, wherein a membrane covers the proximal and distal segments;

[0092] Figure 7 The implant according to the first embodiment is shown without a membrane and placed in an aneurysm, wherein the separation point is arranged proximal to the base body;

[0093] Figure 8 An implant placed in an aneurysm without a membrane according to a first embodiment is shown, wherein the separation point is arranged within the base body;

[0094] Figure 9An implant placed in an aneurysm according to a first embodiment is shown, wherein the membrane covers the proximal segment and the separation point is arranged inside the base;

[0095] Figure 10 shows an implant according to a second embodiment during its deployment within an aneurysm;

[0096] Figure 11 Shows Figure 10 The implant shown is released at a more advanced stage;

[0097] Figure 12 An implant comprising a tulip-shaped base body according to a second embodiment is depicted.

[0098] Figure 13 Shows additional occlusive device inserted into Figure 12 In the implant shown;

[0099] Figure 14 An electrolytically corrodible separation point for severing the implant is shown;

[0100] Figure 15 Another electrolytically corrodible separation point for severing the implant is shown;

[0101] Figure 16 A mechanically releasable, friction-fit based separation point for releasing the implant is shown;

[0102] Figure 17 It is used to release Figure 16 An enlarged view of the mechanically releasable detachment point of the implant is shown in FIG.

[0103] Figure 18 A further example of a mechanically releasable separation point based on a friction fit attachment is shown;

[0104] Figure 19 An insertion aid in the form of a flexible tube is shown;

[0105] Figure 20 A mechanically releasable separation point for releasing the implant based on form closure is shown;

[0106] Figure 21 Another mechanically releasable separation point based on form closure for releasing the implant is shown;

[0107] Figure 22 An implant with a two-part insertion aid is shown;

[0108] Figure 23 Another implant with a two-part insertion aid is shown;

[0109] Figure 24 is an oblique view of another variant of a separation point for separating the implant in the closed state based on form closure.

[0110] Figure 25 Is the closed state from Figure 24 Side view of the separation point.

[0111] Figure 26 Is in the open state from Figure 24 Oblique view of the separation point.

[0112] Figure 27 A separating element with a positive connection between the insertion aid and the implant is shown, which allows electrolytic release;

[0113] Figure 28 Shows the Figure 27 A separate component of the separation element;

[0114] Figure 29 Shows Figure 27 Different perspective views of the separation elements depicted in FIG;

[0115] Figure 30 yes Figure 27 An exploded view of the interlocking members of the separating elements, and

[0116] Figure 31 Shows the use Figure 27 Implant separation performed by the separation element shown in .

[0117] Figure 1 FIG1 is a schematic diagram of the present invention according to a first embodiment, shown in a side view. An implant 1 has been placed in an aneurysm 2, which is indicated by a dotted line. The implant 1 has a base body 6 consisting of a proximal segment 7, a distal segment 8, and a connecting strut 9, by which the two segments are connected.

[0118] The proximal segment 7 is covered by a membrane 12. Both the proximal segment 7 and the distal segment 8 are made of framework struts 10, which form a separate mesh or ring 11. In the proximal segment 7, the framework struts 10 are embedded in the membrane 12. The connecting struts 9 have a curved shape, which ensures that the implant 1 can adapt well to the corresponding conditions of the aneurysm 2 both axially and radially. This flexibility is further enhanced by the region 14 in the distal segment 8 that is free of framework struts 10.

[0119] In the proximal region, the implant 1 is connected to an insertion aid 5 consisting of an insertion wire via a detachment point 4. The detachment point 4 can be designed to be electrolytically detachable, for example, which enables the implant 1 to be detached after it has been successfully placed in the aneurysm 2.

[0120] exist Figure 2 In the figure, the implant 1 is shown in cross section Figure XX Viewed from the distal side, the individual rings 11 formed by the framework struts 10 can be seen, which are covered by a membrane 12. The membrane 12 has a blood flow regulating effect and results in the aneurysm 2 being largely isolated from the blood flow.

[0121] Figure 3 This is a side view of a first embodiment of an implant 1 according to the present invention. Implant 1 also has a distal segment 8 and a proximal segment 7, which are connected to each other via a connecting strut 9. The connecting strut 9 extends in a curved shape. The proximal segment 7 is covered by a membrane 12. Further proximally, implant 1 is connected to an insertion aid 5 via a separation point 4.

[0122] Figure 4 The diagram in Figure 3 , but in this case the separation point 4 is arranged inside the base body 6. This ensures that no protruding ends of the wire remain at the proximal end of the implant 1 after separation of the implant 1.

[0123] exist Figure 5 , the implant 1 is shown in the fully released state. In the present case, the implant 1 is shown with the proximal section 7 covered by the membrane 12 and the distal section 8 uncovered. The separation point 4 is arranged close to the base body 6.

[0124] Figure 6 A corresponding implant 1 is shown, which is Figure 5 The implant 1 of WO 2012 / 051444 PCT / EP ... differs in that the distal section 8 in this illustration has also been provided with a membrane 13. The further covering of the implant 1 with a membrane 13 offers the advantage that the inflow of blood into the aneurysm 2 is largely prevented even in the event of an endoleak.

[0125] Figure 7 A corresponding implant 1 is shown placed in an aneurysm 2, here without providing a membrane. Firstly, an implant 1 of this design serves as a support structure to retain a further occluding device introduced into the aneurysm 2.

[0126] Figure 8 To a large extent corresponds to Figure 7 , but with Figure 7 In contrast, the separation point 4 is arranged inside the base body 6. Thus, a central inwardly curved portion of the base body 6 is produced, thereby preventing a portion of the implant 1 from protruding into the main vessel 15.

[0127] exist Figure 9 In FIG. 1 , another implant 1 is shown, which has a separation point 4 arranged in a base body 6, wherein the proximal section 7 is covered by a membrane 12. The implant 1 thus corresponds largely to Figure 5 The implant in FIG. 1 , but with a different arrangement of the separation points 4 .

[0128] exist Figure 10 FIGURE 2 shows a second embodiment of an inventive implant 1, which, after expansion, assumes the shape of a tulip flower. Implant 1 is introduced into aneurysm 2 via blood vessel 15 through microcatheter 3 and deployed by advancing implant 1 or retracting microcatheter 3. In the state shown here, only distal segment 8 of implant 1 has been deployed, while more proximal regions of implant 1 remain within microcatheter 3.

[0129] exist Figure 11 middle, Figure 10 The implant 1 is shown at a more advanced stage of release. The separation point 4 can be seen, but it is still located within the microcatheter 3.

[0130] Figure 12 A side view of an implant according to a second embodiment is shown. Implant 1 is composed of partially interconnected struts 16, forming a network of interspaces 11 between them. Implant 1 includes a plurality of petal-shaped segments 17 extending from the proximal end of implant 1, initially radially outward and slightly proximally, and then further distally and radially inward. In this manner, petal-shaped segments 17 adhere closely to the inner wall of aneurysm 2. A central region 14 at the distal end of implant 1 remains free of struts 16, resulting in an opening whose size can be larger or smaller, depending on the size of aneurysm 2.

[0131] At the proximal end, the individual struts 16 of the implant 1 are connected to a separation element 18, which is arranged in an annular form around the insertion aid 5. The insertion aid 5 is of tubular design and has a lumen through which further occluding devices can be introduced into the implant 1. Release of the implant 1 can be achieved by subjecting the annular separation element 18 to electrolytic corrosion. In particular, the implant 1 can initially be inserted into the aneurysm 2, causing it to expand there without any release occurring at the separation element 18. Further occluding devices can then be introduced via the insertion aid 5 to fill the interior space of the implant 1. Subsequently, when this process is complete, an electric current is applied to the annular separation element 18 to release the implant 1. Finally, the insertion aid 5 and the microcatheter 3, not shown here, are retracted proximally and removed from the vascular system.

[0132] Figure 13 It is shown how the additional occluding means 19 is introduced into the interior space of the implant 1 via the insertion aid 5. The implant 1 corresponds to Figure 12 By retracting the microcatheter 3, the implant 1 has expanded in the aneurysm 2, causing the struts 16 of the implant 1 to be placed in place against the inner wall of the aneurysm 2. However, detachment of the implant 1 has not yet occurred.

[0133] Figure 14 and15 Different ways of electrolytically separating the implant 1 are shown. In both cases, an annular separating element 18 is arranged around the tubular insertion aid 5, said element being connected to the proximal end of the implant 1, which is only hinted at here. The current can be passed through a ( Figure 14 ) or two ( Figure 15 ) An electrically conductive separation wire 20 is applied to the separation element 18, which enables electrolytic corrosion to occur, thereby leading to separation and ultimate release of the implant 1. The separation wire 20 is suitably insulated so that the current is applied to the separation point in a precisely targeted manner. Alternatively, the separation wire 20 can extend through the lumen of the insertion aid 5, or the metal mesh of the catheter-like insertion aid can serve as a suitable conductor.

[0134] exist Figure 16 and 17 , a detachable connection of an implant 1 and an insertion aid 5 based on frictional engagement is shown. Radial projections 21 in the form of elastic pads are arranged around the internally hollow insertion aid 5. The proximal end 23 of the implant 1, which in this case comprises a separate strut of the implant 1 protruding in the proximal direction, is provided with a spherical thickening 22 and is clamped between the microcatheter 3 and the insertion aid 5. The interaction of the microcatheter 3, the insertion aid 5, the proximal end 23 of the implant 1, and in particular the radial projections 21 and the thickening 22, establishes a frictional connection and prevents premature detachment of the implant 1.

[0135] Figure 17 This principle is shown in detail. Once the microcatheter 3 is retracted in the proximal direction (upper left in this illustration), the proximal end 23 of the implant 1 can be radially expanded, causing the implant 1 to detach. In order to enable the treating physician to check the detachment process, a radiopaque marker 24 is additionally provided on the microcatheter 3.

[0136] Figure 18 Figures a, b, and c show other mechanically separable separation points based on frictional locking, where a combination of frictional and form-locking locking is achieved by a suitable thickening 22 arranged at the proximal end 23 of the implant 1. The thickening 22 of the proximal end 23 of the implant 1 is arranged between the radial projections 21 of the insertion aid 5, and vice versa. In each case, a microcatheter 3 (not shown here) surrounds the device and prevents the proximal end 23 from expanding in the radial direction. Therefore, the implant 1 cannot be separated until the microcatheter 3 has been retracted in the proximal direction.

[0137] exist Figure 19 In FIG, a tubular insertion aid 5 is shown, on which radial protrusions 21 are arranged to produce a friction connection. In addition, various slits 25 are provided in the insertion aid 5, which increase flexibility and help the implant 1 to be advanced through the microcatheter 3, particularly in narrow blood vessels.

[0138] Figure 20 The proximal end 23 of the implant 1 is depicted as being securely fastened in a form-fitting manner. A form-fitting separation element 26 is arranged at the proximal end 23, which engages in a corresponding recess 27 in the insertion aid 5. When the microcatheter 3 is retracted in the proximal direction, the form-fitting separation element 26 can radially expand and exit the recess 27, leading to the release of the implant 1. To visualize the retraction process of the microcatheter 3, the catheter is also provided with a radiopaque marker 24.

[0139] Figure 21 , another example of a form-closed separation element 26 is shown, wherein the separation element 26 is shaped like a segment of a circle and is designed to fit into a corresponding recess 27 provided in the insertion aid 5. When the microcatheter 3 is retracted, the separation element 26 can leave the recess 27, as indicated by the arrow.

[0140] exist Figure 22 and 23 In FIG, it is shown that the insertion aid 5 can consist of two parts. Figure 22 and 23 Basically the same, but Figure 22 shows the separation of shape closure, while Figure 23 The frictional separation described above is shown. The insertion aid 5 with a lumen is formed more rigidly in the proximal portion 28 than in the more flexible distal portion 29. To this end, the distal portion 29 has a helical structure in the form of two layers of highly flexible hollow strands. To also be able to transmit torsional forces, the helical structures have opposite directions of rotation.

[0141] Figure 24 Another variant for fastening an implant 1 to an insertion aid 5 via a form-locking connection is depicted, in which at least one separation element 31 extends proximally from the proximal end of the implant 1 and is retained in a form-locking manner by a retaining element 30 provided on the insertion aid 5, which thus engages around the separation element 31. The separation element 31 has a spherical shape. The retaining element 30 is made of a material with shape memory properties. The microcatheter 3, not shown here, is arranged around the retaining element 30 in the closed state and prevents the latter from assuming the expanded second configuration and releasing the separation element 31. Figure 25 is a side view of the same situation.

[0142] Figure 26 The microcatheter 3 is shown after it has been retracted in the proximal direction. The retaining element 30 assumes a pre-set, open second configuration, so that the detachment element 31 can be withdrawn, which in turn leads to detachment of the implant 1 .

[0143] Figure 27Represents a separation element 46 based on a combination of mechanical form-closed locking and electrolytic separability. The separation element 46 is shown from the front (a), the side (b) and the back (c). The separation element 46 consists of three components: an insertion aid end piece 32, which is located at the distal end of the insertion aid not shown here; an implant end piece 33, which is located at the proximal end of the implant not shown here; and an insulating element 34, which electrically separates the insertion aid end piece 32 and the implant end piece 33 from each other, even when they are engaged with each other. The insertion aid end piece 32 and the implant end piece 33 overlap, i.e. the distal region of the insertion aid end piece 32 is located distal to the proximal region of the implant end piece 33.

[0144] exist Figure 28 , the individual components of the separation element 46 are shown from the front (a), from the side (b) and from the rear (c). The insertion aid end piece 32 comprises a first short tubular member 35 which is radially closed. This is connected to a second short tubular element 37 with a radial interruption 38 via a connecting web 36.

[0145] The implant end piece 33 has an almost identical structure, i.e. it comprises a radially closed first short tubular element 39, a radially provided second short tubular element 41 with interruptions 42 and a connecting web 40 arranged between the two. However, the positions of the insertion aid end piece 32 and the implant end piece 33 are reversed, i.e. the second tubular elements 37 and 41 provided with interruptions 38, 42 face each other, wherein the interruptions 38, 42 have an offset of 180°.

[0146] The insulating element 34 has a proximal portion 44 and a distal portion 45, with the second tubular element 37 of the insertion aid end piece 32 engaging with and surrounding the distal portion 45, while the second tubular element 41 of the implant end piece 33 engages with and surrounding the proximal portion 44. In this case, the recesses present in the proximal and distal sections 44, 45 are aligned with the second tubular elements 37, 41, i.e., the recesses are completely or largely filled by them. In this manner, the insertion aid end piece 32 and the implant end piece 33 are interlocked with each other, but the region of the insulating element 34 is always arranged between the two, so that the voltage applied to the insertion aid end piece 32 is not transmitted to the implant end piece 33, resulting in the two end pieces 32, 33 being insulated from each other.

[0147] Equally important is the electrolytically corrodible separation point 43, which dissolves upon application of an electric current, causing separation at this point. The implant is thus released along with the remaining attached portion of the separation element 46, while the proximal first tubular element 35 of the insertion aid endpiece 32 remains attached to the insertion aid and is retracted proximally with it. The separation point 43 is the narrow connection point between the first tubular element 35 and the connecting web 36.

[0148] Figure 29 The interconnected separation element 46 with the insertion aid end piece 32, the implant end piece 33, and the insulating element 34 is shown from different perspectives. It can be seen how the insertion aid end piece 32 and the implant end piece 33 engage one another in a form-fitting manner, while the area of ​​the insulating element 34 always prevents direct contact between the insertion aid end piece 32 and the implant end piece 33. Furthermore, it can be seen that the lumen of the separation element 46 is provided for connection to the lumen of a tubular or hose-shaped insertion aid. This thus enables the introduction of additional occluding devices, such as coils or embolic agents, into the aneurysm.

[0149] Figure 30 3 is an exploded view of the separating element 46, from which it can be seen that the second tubular elements 37 and 41 of the insertion end piece 32 and the implant end piece 33 - both of which are provided with interruptions - overlap each other with the insulating element 34 located therebetween. The interruptions 38, 42 in the end pieces 32, 33 and the recesses in the insulating element 34 designed to fit into the second tubular elements 37, 41 are both radially offset by 180°.

[0150] at last, Figure 31 The figure shows the separation of an implant at the separation element 46. An electric current is applied to the separation point 43 via the insertion aid and the metal insertion aid end piece 32, which is connected as an anode. This arrangement causes the corrodibly designed separation point 43 to dissolve, and the proximal region of the insertion aid end piece 32 to disconnect from the rest of the separation element 46. The latter is released along with the implant, while the proximal portion of the insertion aid end piece can be retracted proximally and removed from the vascular system. The metal portion of the separation element 46 that remains on the implant can, for example, be made of magnesium, which dissolves over time, resulting in the disappearance of the no longer needed foreign body. The separation element 46 ensures a secure, positive connection between the insertion aid and the implant, ensuring that the implant remains in place even if the surrounding microcatheter is retracted proximally, causing the separation element 46 to release. The implant is not released until a voltage is applied to the separation point 43. Furthermore, the positive connection between the insertion aid and the implant allows the transmission of torsional movements.

Claims

1. An implant for treating arteriovenous malformation, wherein: The implant can be brought to a target site in a patient's vascular system in a compressed state via a microcatheter, wherein the implant is preset to a second configuration that causes the implant to assume an expanded state when released from the microcatheter, wherein the implant is detachably connected to an insertion aid at a first separation point, wherein the implant in the expanded state has a base body, the base body comprising a proximal segment and a distal segment, the proximal segment and the distal segment being dome-shaped, the convex side of the dome of the proximal segment facing in a proximal direction, and the convex side of the dome of the distal segment facing in a distal direction, It is characterized by: The proximal segment and the distal segment are connected to one another by a plurality of connecting struts, wherein the connecting struts do not intersect and do not intertwine with one another so that they can be compressed or stretched independently of one another, wherein the connecting struts are designed in such a way that they enable adaptation to the aneurysm in the axial and radial directions.

2. The implant according to claim 1, wherein The arteriovenous malformation is an aneurysm.

3. The implant according to claim 1, wherein The connecting struts disposed between the proximal and distal segments are curvilinear in configuration.

4. The implant according to claim 1, wherein The proximal segment and / or the distal segment are composed of frame struts that are at least partially connected to one another.

5. The implant according to claim 4, characterized in that In the expanded state, the framework struts form a mesh or ring in the proximal and / or distal segments.

6. The implant according to claim 4, characterized in that The distal segment centrally includes a region devoid of framework struts, the region being expandable and compressible.

7. The implant according to claim 1, wherein The proximal section is provided with a membrane at least partially covering the proximal section.

8. The implant according to claim 7, characterized in that The distal segment is provided with a membrane at least partially covering the distal segment.

9. The implant according to claim 7, characterized in that The connecting struts are at least partially covered with a membrane.

10. The implant according to claim 1, wherein In the expanded state, the base body has approximately the shape of a sphere, an ellipsoid, an oval, a tulip or a cylinder with a convex, outwardly curved base surface.

11. The implant according to claim 1, wherein When the base body is in the expanded state, the distal end of the insertion aid is located inside the base body.

12. The implant according to claim 1, wherein The insertion aid has a tubular design and comprises a lumen.

13. The implant according to claim 12, characterized in that The insertion aid having the tubular design protrudes in the distal direction beyond the first separation point.

14. The implant according to claim 1, wherein A first decoupling element is arranged outside the insertion aid, which is connected to the proximal end of the implant, wherein release of the implant can be caused by applying a voltage to the first decoupling element.

15. The implant according to claim 14, characterized in that The first separating element is arranged annularly around the insertion aid.

16. The implant according to claim 1, wherein The insertion aid has a radial protrusion on the outside at its distal end and extends into the implant together with the distal end, so that a friction connection is provided between the insertion aid, the implant and the microcatheter or a sheath surrounding the distal end of the insertion aid, wherein the implant is released by moving the microcatheter or sheath in the proximal direction relative to the implant and the insertion aid.

17. The implant according to claim 16, characterized in that The radial protrusion is made of elastic material.

18. The implant according to claim 12, wherein A second separation element is arranged at the proximal end of the implant, which engages in a form-closed manner in a recess provided for this purpose in the insertion aid of tubular design, so that separation of the implant occurs by moving the microcatheter or the sheath around the distal end of the insertion aid relative to the implant and the insertion aid in the proximal direction.

19. The implant according to claim 1, wherein At least one third separation element extends in a proximal direction at the proximal end of the implant, and the at least one third separation element is fixed in a form-closed manner by a retaining element arranged on the insertion aid, wherein the retaining element is made of a material with shape memory properties and the retaining element is preset to a second structure, when the second structure is assumed, the at least one third separation element is released and separation of the implant occurs, wherein the retaining element is prevented from assuming the second structure by a surrounding microcatheter or another sheath surrounding the retaining element.

20. The implant according to claim 1, wherein An insertion aid end piece is arranged at the distal end of the insertion aid, and the insertion aid end piece has a second separation point that can be electrolytically corroded, wherein the insertion aid end piece is connected to the implant end piece arranged at the proximal end of the implant in a form-closed manner, and wherein an insulating element is arranged between the insertion aid end piece and the implant end piece in such a way as to avoid direct contact between the insertion aid end piece and the implant end piece.

21. The implant according to claim 20, characterized in that The insertion aid end piece and the implant end piece each have a first tubular element and a second tubular element, a connecting web is arranged between each first tubular element and the second tubular element, and the second tubular elements each have a radial interruption, wherein the insertion aid end piece and the implant end piece are connected together in such a way that the second tubular element of the implant end piece is arranged proximal to the second tubular element of the insertion aid end piece.

22. The implant according to claim 1, wherein The insertion aid has a hose-shaped design and comprises a lumen.

23. The implant according to claim 22, wherein The insertion aid having the hose-shaped design protrudes in the distal direction beyond the first separation point.

24. The implant according to claim 22, wherein A second separation element is arranged at the proximal end of the implant, which engages in a form-closed manner in a recess provided for this purpose in the insertion aid having the hose-shaped design, so that separation of the implant occurs by moving the microcatheter or the sheath around the distal end of the insertion aid relative to the implant and the insertion aid in the proximal direction.

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