Arrangement for feeding a medical implant, wire and catheter
Patent Information
- Application Number
- AU2024419904
- Authority / Receiving Office
- AU · AU
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-01-08
- Filing Date
- 2024-12-20
- Publication Date
- 2026-08-27
Smart Images
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Abstract
Description
The invention relates to an assembly for delivering a medical implant into a hollow organ of the body, with a wire and a compressible and expandable medical implant which is tubular in construction. In the compressed state, the implant is detachably connected to the wire by at least one engaging element for the transmission of force in the axial direction, wherein the engaging element has at least one projection which extends radially outwards and engages in the implant. In the at least partially expanded state, the implant can be released in a detachment direction by a relative movement between the engaging element and the implant. The invention further relates to a wire for delivering a medical implant into a hollow organ of the body, and to a catheter. The aforementioned assembly is known, for example, from the Applicant’s application WO 2013 / 107783 Al. A wire having the features of the preamble of claim 14 is also known from this prior art. This assembly or this wire has proved to be excellent in practice and enables the reliable delivery of an implant, such as a stent or a flow diverter, for example, through a catheter to the treatment site. When released from the catheter, the implant is uncoupled from the wire and remains at the treatment site. The wire is retracted through the catheter. The implant is released at the treatment site by a relative movement in the axial direction between the catheter and the implant. Upon exiting the catheter, the implant deploys or expands, wherein the expansion movement advances successively in the proximal direction of the implant as the release progresses. When the implant expands in the region of the engaging element, the implant is freed from the wire by the radially outward movement and the implant and the engaging element are separated. The implant is fully released and expands at the desired location within the vessel to be treated. If the radially outward movement of the implant is restricted, for example by patient-specific vascular characteristics in the region of the treatment site, so that the radial distance between the implant and the engaging element is small, the release of the implant can become more difficult. The invention is therefore based on the objective of improving the known assembly in a manner such that the implant can be released as reliably as possible even under difficult conditions. A further objective of the invention is to provide a suitable wire as well as a catheter. In accordance with the invention, with regard to the assembly, the objective is achieved by the subject matter of claim 1; with regard to the wire, the objective is achieved by the subject matter of claim 14; and with regard to the catheter, the objective is achieved by the subject matter of claim 15. Specifically, the objective is achieved by an assembly for delivering a medical implant into a hollow organ of the body, with a wire and a compressible and expandable medical implant which is tubular in construction. In the compressed state, the implant is detachably connected to the wire by at least one engaging element for the transmission of force in the axial direction. The engaging element has at least one projection which extends radially outwards and engages in the implant. In the at least partially expanded state, the implant can be released in a detachment direction by a relative movement between the engaging element and the implant. In accordance with the invention, the engaging element has at least one sliding surface which is inclined and / or curved in the detachment direction. The sliding surface cooperates with the projection in order to release the implant. The invention has the advantage that the engaging element and the implant itself can be reliably detached even if the distance between the engaging element and the implant is relatively small, because the implant can slide on the sliding surface during release, whereupon uncoupling of the implant from the wire is assisted. This prevents the implant from becoming entangled with the engaging element and the wire can be safely retracted into the catheter. This is achieved by means of the inclined and / or curved sliding surface. The sliding surface cooperates with the projection in order to release the implant. The sliding surface is therefore suitable for supporting or is adapted to support the release of the implant. Advantageously in this regard, the sliding surface and the projection are constructed as a single piece or as a monolithic component. It is also possible to form the sliding surface and the projection in two parts. In this case, the sliding surface and the projection are two separate components, for example two sleeves which are disposed axially immediately behind one another, whereas other embodiments are possible. The projection and the sliding surface cooperate in the sense that the sliding surface causes, or at least contributes to, bringing the implant to the height position required to surmount the projection. The height position can be, but does not have to be, the radially outer surface of the projection. The sliding surface and the projection are disposed in the axial direction of the implant or the wire in a manner such that a transitional movement of the implant is possible, for example when the sliding surface and the projection are connected or connectable, so that the sliding surface transitions directly into the projection. Other embodiments are possible . Because of the inclination and / or curvature, the sliding surface extends in a direction which differs from a vertical side of the projection. Because the direction of inclination or the direction of curvature extends in the detachment direction, the detachment procedure is supported by the sliding surface. The detachment direction is the direction in which the implant is released by the relative movement between the engaging element or wire and the implant. If, for example, the wire is retracted into the catheter in the proximal direction with the implant being stationary, the detachment direction of the implant extends in the distal direction. Prior to release, the implant is located proximally to the catheter tip and after release, it is distally to the catheter tip. The sliding surface is then also in the distal direction, so that the implant can slide on the sliding surface when the engaging element moves in the proximal direction. The detachment direction is not limited to the longitudinal direction of the implant. In fact, the detachment direction in general refers to the relative movement between the engaging element and the implant, which occurs in addition to the expansion movement of the implant, in order to disengage the implant and the engaging element in the radial direction. The detachment direction can extend in the longitudinal direction of the implant or in the circumferential direction of the implant. The two alternatives are the subject matter of preferred embodiments of the invention, which are described in more detail below. The sliding surface also enables the implant to be uncoupled from the wire even in a partially expanded state, in which the implant and the engaging element overlap, i.e., they are in partial engagement. This is accomplished by inclining and / or curving the sliding surface in the detachment direction. When the wire is retracted into the catheter in the proximal direction, the implant slides on the sliding surface and is pushed radially outwards. The implant is thus freed from the wire . The mechanism described above for the partially expanded state with partial engagement applies equally to a partially expanded state in which the radial distance between the engaging element and the implant is so small that engagement can occur during release. The invention is suitable for self-expanding medical implants. The medical implant of the assembly can therefore be self-expanding. Implants of this type are known and are usually manufactured from a shape memory material. The implant may preferably have a mesh structure, in particular a tubular wall formed from a mesh structure. The mesh structure may comprise a network of braided filaments or wires, or a single braided filament or single wire. The network forms meshes. The mesh structure may also be a monolithic mesh structure formed from webs, for example a laser-cut mesh structure . The monolithic mesh structure forms cells. The invention is not limited to a specific type of engagement. The wire may be connected to the implant in a different manner. As an example, the engaging element might engage in the mesh structure. It is also possible for the engaging element to be detachably connected to end loops or end meshes or end rhomboids of the implant. Detachable connections between the implant and the engaging element may also be provided by additional components, in particular radiographic markers. These could be crimped marker sleeves, for example. The engaging element may have a plurality of projections. The projections respectively interact with a sliding surface in order to release the implant. The implant and wire assembly in accordance with the invention is treated as a module which is disclosed and claimed independently of the catheter with which the assembly is transported to the treatment site. In addition, the combination of a catheter and the assembly in accordance with the invention is also disclosed and claimed. The wire for delivering the medical implant as such, i.e. with no implant and with no catheter, is also disclosed and claimed in the context of the invention. The wire is suitable for obtaining the advantages discussed hereinabove in connection with the delivery of an implant and to this end has a modified engaging element in accordance with the invention which is described hereinabove. A wire of this type is also known as a transport wire. Preferred embodiments of the invention are claimed or defined in the dependent claims. Thus, the sliding surface may be inclined and / or curved in the longitudinal direction of the implant, in particular in the distal longitudinal direction. This embodiment has the advantage that the detachment direction extends parallel to the wire. Thus, in the case of a relative movement between axially moved wire and stationary implant, the wire can be retracted into the catheter. This corresponds to the usual detachment procedure when the implant is anchored in place at the treatment site and the wire is retracted in the proximal direction. The inclination of the sliding surface in the distal longitudinal direction means that a spatial component of the sliding surface extends in the distal direction. This is not the case for a surface which is orthogonal to the longitudinal axis of the wire. When the wire with the engaging element is drawn in a proximal direction, the sliding surface moves with respect to the implant, resulting in a relative movement between the engaging element and the implant, whereupon the engaging element and the implant are separated from each other, or a further unwanted engagement does not occur. Preferably, the inclined sliding surface comprises a chamfer which is formed in at least the region of the outer edge of the projection. The chamfer can be produced easily, because only the outer edge of the projection needs to be processed. It is not necessary to process the entire side of the projection. It is sufficient for a portion of the projection to be provided with a chamfer or to be chamfered, in fact in the region of the outer edge of the projection, i.e., where it can become entangled with the implant if the distance between the engaging element and the implant is not sufficiently large . In a further embodiment, the chamfer starts at the base of the projection. The chamfer therefore extends across the entire side of the projection. This has the advantage that a sliding surface which is as long as possible is formed. Safeguarding against entanglement is enhanced. At least at one axial end, the engaging element may have a conical profile with the corresponding inclined projection, the axial end forming the inclined sliding surface. This embodiment has the advantage that the engaging element, along with the projection, is inclined, so that practically no edges which could hinder uncoupling are formed in the detachment direction. This minimizes the risk of entanglement. The projection, and thus the sliding surface, are part of the conical surface of the engaging element and are therefore inclined according to the conicity of the axial end of the engaging element. In a further preferred embodiment, the engaging element is curved in the axial direction of the implant, in particular in the distal direction of the implant, wherein the projection is formed with a corresponding curvature on the outer curve of the engaging element and forms the curved sliding surface. This means that the entire engaging element, along with the projection, is curved and therefore also has no edges which could hinder the detachment procedure. This minimizes the risk of entanglement. The projection is part of the curved engaging element and is therefore also correspondingly curved. The engaging element can, for example, be cut from a tube and be appropriately profiled. In a further particularly preferred embodiment, the inclined and / or curved sliding surface comprises a tube which encases the engaging element. This embodiment has the advantage of being particularly simple and versatile as regards manufacture. Mechanical processing of the engaging element is not required. The tube may, for example, be a flexible tube or a shrink tube. The sliding surface is therefore generated by an additional element, namely the tube, which is disposed over and encases an engaging profile core. The tube, together with the engaging profile core, forms the engaging element, specifically the projection or the projections with the sliding surface. The encased engaging profile core is the core of the tube and stabilizes it. The outer contour of the engaging element is determined by the shape of the tube. For the engaging profile core, engaging elements which are known per se can be used, which are modified by the combination with the tube in a manner such that a projection or projections (depending on the engaging profile core) are formed which have inclined and / or curved sliding surfaces because of the tube. Manufacture is therefore simple and can be carried out in a versatile manner using known engaging elements. The tube encases the engaging element in a geometrically undefined manner. It is substantially adapted to the contour of the engaging element, i.e., it does not directly follow the contour and does not lie close to the engaging element. Outer edges of the engaging element are covered by the tube, which here forms a rounded sliding surface or a rounded sliding surface section. In the radially outer region of the engaging element, the tube lies closer to the contour than in the radially inner region. The tube therefore forms the rough contour of the engaging element. The sliding surface forms a smooth or continuous transition from radially inner to radially outer . If a plurality of engaging elements are disposed on the circumference of the wire, the tube follows the resulting height profile in the circumferential direction in a manner such that the engaging elements can engage in the implant, for example in the mesh structure. The tube forms the inclined and / or curved sliding surface because the tube extends substantially obliquely, in contrast to the perpendicular extent with respect to the tubular shape of the implant or in contrast to the perpendicular flank or side of the engaging profile core . The tube may be inclined and curved differently in different sections. In its overall extent in the detachment direction, the tube forms an inclined freeform surface for releasing the implant. The freeform surface acts as the sliding surface. In contrast, the chamfer forms a geometrically defined, in particular straight, sliding surface which is inclined. The basic concept is the same as with the chamfer or with the curved shape of the engaging element, namely to support the detachment procedure between the implant and the wire by orientating the sliding surface differently from the vertical. The tube can be flexible or pliable, for example a polymer tube. Due to its flexibility, the tube stretches over the engaging profile core. The flexible tube therefore adapts itself to its rough contour. Alternatively, the tube may be a shrink tube which is stretched over the engaging profile core by means of a heat treatment or other treatment and is therefore adapted to its rough contour. The shrink tube can be brought from an initial state to a compressed state, in particular by heat treatment. The ratio between the outer diameter of the tube in its initial state and the outer diameter of the tube in the compressed state is preferably between 2:1 and 6:1, in particular between 3:1 and 6:1, in particular between 4:1 and 6:1, in particular between 5:1 and 6:1. Preferably, the outer diameter of the tube in the initial state is at least twice as large, in particular at least three times as large, in particular at least four times as large, as the outer diameter of the tube in the compressed state. The tube, in particular the shrink tube, is preferably produced from plastic, for example from PTFE, PE, PVC and / or FEP. Other materials are possible. In particular, the tube is produced from a material which provides a ratio between the outer diameter of the tube in its initial state and the outer diameter of the tube in the compressed state of 2:1 to 6:1. The thickness of the tube, in particular of the shrink tube, or the thickness of the tube in the radial direction, is preferably between 20 pm and 200 pm, in particular at least 50 pm, in particular at least 100 pm, in particular at least 150 pm. A different tube thickness is conceivable . Alternatively or in addition, the length of the projection in the radial direction of the engaging element may be at least 1.5 times, in particular at least 2 times, in particular at least 2.5 times, the thickness of the tube, in particular of the shrink tube, or of the thickness of the tube in the radial direction. It is possible for a plurality of engaging elements to be disposed spaced apart from each other on the transport wire. The engaging elements may have different outer diameters and / or be spaced apart from each other by intermediate elements which have a different outer diameter to the engaging elements. The inner diameter of the shrink tube is preferably constructed in a manner such that it can be adapted to the outer diameter of all engaging elements and / or intermediate elements which are disposed on the transport wire, or to the transport wire itself, even if the engaging elements, intermediate elements and the transport wire have different outer diameters . It is possible for a plurality of tubes, in particular a plurality of heat shrink tubes, to be disposed on the transport wire. The number of engaging elements and the number of shrink tubes may be the same or different. As an example, it is possible for one tube to extend over all the engaging elements. Alternatively, one tube may be provided per engaging element. The shrink tube is advantageously adaptable to the contour of the engaging element in a manner such that the shrink tube does not directly follow the contour and does not lie tightly against the engaging element. This should preferably be understood to mean that spaces are formed between the engaging element and the shrink tube. Such spaces can be filled using UV and / or heat-curing adhesive. In a further embodiment of the invention, the sliding surface is inclined and / or curved in the circumferential direction of the implant. This ensures that the detachment procedure is actively supported by rotation of the wire. Rotating the wire results in a relative movement between the implant and the engaging element in the circumferential direction. Here, the implant slides on the sliding surface in the circumferential direction and is pushed radially outwards by it because of the inclination or curvature. If the distance between the implant and the engaging element is too small due to an insufficient expansion movement and an overlap occurs, the doctor can force uncoupling by rotating the wire. When the implant and wire are out of engagement because of the rotation, the wire can be retracted into the catheter in a proximal direction in the usual manner. It is possible to combine embodiments in which the sliding surface is inclined and / or curved in the circumferential direction and in the longitudinal direction of the implant. As an example, the sliding surface may be disposed in a spiral shape of increasing diameter. This results in a screw action, in which the engaging element rotates and simultaneously executes a forward movement relative to the implant. The height position of the implant and at the same time the relative position between wire and implant in the axial direction are changed. In a further embodiment, it is possible for a plurality of, in particular two, engaging elements, each with at least one sliding surface, to be disposed in a manner which is axially spaced apart from each other in the longitudinal direction of the wire, wherein the sliding surfaces of the engaging elements are orientated in the same direction. This increases the reliability of the coupling of the implant and the wire by the multiple connection. In this regard, the detachment functionality is retained. For this purpose, the sliding surfaces are provided on both engaging elements and orientated in the same direction, so that they support the detachment procedure in the event of a relative movement between the wire and the implant in the same direction. The engaging element can be associated with a proximal stop (also known as a pushing sleeve) which is disposed in a manner which is axially spaced from the engaging element in the longitudinal direction of the wire, with the formation of a free space. This basic structure of the assembly is constructed in order to accommodate an additional component, for example a radiographic marker, and is described in the aforementioned prior art publication, but with the difference that the engaging element here is modified for easier detachment. This embodiment can be combined with all other embodiments or examples of this application and is also disclosed and claimed in this combination. Preferably, the engaging element has a plurality of projections which are disposed on the circumference of the engaging element in a distributed manner, each having at least one sliding surface and forming an engaging section. This improves the reliability of the connection and produces a uniform transmission of force from the wire to the implant over the circumference of the engaging element. The sliding surfaces of the projections are respectively orientated in the same direction. This does not preclude the possibility of further sliding surfaces being provided which are orientated in other directions . The engaging element may have a plurality of engaging sections in the longitudinal direction of the wire, wherein the projections of the different engaging sections are disposed in a manner which is offset in the circumferential direction. This improves both the reliability of coupling, because of the increased number of projections, as well as the uniformity of the transmission of force, because the projections of the different engaging sections are disposed in a manner which is offset in the circumferential direction. The projections of a first engaging section may have sliding surfaces in at least the proximal direction, and the projections of a second engaging section may have sliding surfaces in at least the distal direction. The engaging element therefore enables a detachment procedure in both axial directions. This may be advantageous if the uncoupling of the implant has to be supported particularly strongly by an axial movement of the wire and therefore of the engaging element. In general, each projection engages in a single mesh or a single cell of the mesh structure. The invention will now be described in more detail below with the aid of exemplary embodiments and with reference to the accompanying drawings, in which Fig . 1 shows a perspective view of an assembly according to an exemplary embodiment of the invention with two engaging elements (with no implant); Fig . 2 shows a perspective view of an engaging element for an assembly according to Fig. 1; Fig . 3 shows a view of an assembly according to a further exemplary embodiment of the invention with an engaging element and a stop (with no implant); Fig . 4 shows a side view of the engaging element according to Fig. 3; Fig . 5 shows a perspective view of of an assembly according to embodiment of the invention engaging sections; an engaging element a further exemplary with a plurality of Fig . 6 shows a perspective view of an engaging element of an assembly according to a further exemplary embodiment of the invention with two engaging sections; Fig . 7 shows a perspective view of of an assembly according to embodiment of the invention surfaces; an engaging element a further exemplary with rounded sliding Fig. 8 shows a perspective view of an assembly according to a further exemplary embodiment of the invention with a shrink tube (with no implant); Fig. 9 shows a side view of an assembly with the engaging element according to Fig. 8 (with no implant); Fig. 10 shows a front view of an assembly according to a further exemplary embodiment of the invention, in which the detachment direction extends in the circumferential direction of the implant; Fig. 11 shows the assembly according to Fig. 10 during release of the implant; Fig. 12 shows a perspective view of an engaging element for an assembly according to Fig. 1 and Fig. 13 shows a perspective view of an engaging element for an greater assembly according to curvature than Fig. 2. Fig. 3 with a Fig. 1 shows an exemplary embodiment in accordance with the invention of an assembly for delivering a medical implant 11 into a hollow organ of the body, which is particularly, but not exclusively, suitable for the treatment of neurovascular diseases, such as for stroke treatment, for example. The assembly comprises a wire 10, which can also be referred to as a transport wire or as a retaining wire, and the implant 11. The assembly of wire 10 and implant 11 forms a module which is preloaded in a catheter (not shown). The module is disclosed and claimed in the context of the application, as is the wire 10 with no implant 11. Furthermore, the combination of catheter and assembly or module is disclosed and claimed; this usually forms the commercially unit which is marketed. The implant 11 is tubular in shape and is compressible and expandable in a manner which is known per se in order to be transported through the catheter to the lesion to be treated. The implant 11 is preferably self-expandable. This can usually be accomplished by fabricating the implant 11 from a shape memory material such as nitinol, for example. The invention is not limited to specific implant materials. Other implant materials are possible. The tubular implant 11, specifically its wall, is formed from a mesh structure. The mesh structure may be constructed as a network or as a monolithic mesh structure. Reference in this regard should be made to the discussions in the introductory description of the application. Examples of such implants are stents or flow diverters. Other implants 11 which can be detachably connected to the wire 10 are possible. The wire 10 is configured in a manner which is known per se and, for example, has coils which are disposed on a core (see Fig. 3) . Other embodiments of the wire 10 are possible . In the preloaded state, i.e. in the catheter, the implant 11 is compressed and detachably connected to the wire 10. To this end, in the assembly according to Fig. 1, a plurality of, specifically two, engaging elements 12 are provided which engage in the mesh structure of the implant 11 in order to enable forces to be transmitted from the wire 10 to the implant 11 in the axial direction. The connection between the wire 10 and the implant 11 is detachable in order to uncouple the implant 11 from the wire 10 when the implant 11 is released from the catheter at the treatment site. In its at least partially expanded state, the implant 11 can be released in a detachment direction by a relative movement between the engaging elements 12 and the implant 11. The relative movement between the engaging elements 12 and the implant 11 should be distinguished from the radial expansion of the implant 11, in which the implant 11 moves radially outwards. The implant 11 is initially detached from the wire 10 and its engaging element 12 by the radial expansion and then finally uncoupled by a further movement of the wire 10 relative to the implant 11. The relative movement therefore occurs when the wire 10 is is moved relative to the implant 11. The relative movement occurs in the longitudinal direction of the implant 11 and / or in the circumferential direction of the implant 11. In the examples according to Figures 1 to 9, the relative movement occurs in the longitudinal direction of the implant 11. In the examples according to Figures 10 and 11, the relative movement at least initially occurs in the circumferential direction of the implant 11. A combination is possible. This will be discussed in more detail below. The engaging element 12, or the two engaging elements 12, will be discussed below in more detail with the aid of Figures 1 and 12; they have been modified for reliable detachment from the implant 11. In Fig. 1, both engaging elements 12 are substantially identical in construction. Deviations are due to manufacturing processes. Other combinations are possible. The discussions below apply to both engaging elements 12. The engaging element 12 is constructed to be in the shape of a sleeve. This is also the case for the exemplary embodiments shown in Figures 3 to 13. The engaging element 12 has a central opening through which, in the installed state, the wire 10 extends, specifically the core of the wire 10. This can clearly be seen in Figures 1 and 3. The engaging element 12 can be rotatably or non-rotatably connected to the wire 10. The engaging element 12 has a plurality of, specifically three, projections 13, which extend radially outwards. The function of these projections 13 is to engage in the implant 11, specifically into the mesh structure of the implant 11, when the implant 11 is disposed on the wire 10 in a compressed state. The projections 13 can also be described as the points of a crown, as lugs, vanes or as teeth. A different number of projections 13, in particular more than three projections 13, is possible. The projections 13 respectively have a sliding surface 14 in the form of a chamfer 15, which is inclined in the detachment direction. In the example shown in Fig. 1, the sliding surfaces 14 of the two engaging elements 12 are inclined in the same direction. The detachment direction results from the relative movement between the engaging element 12 or the wire 10 and the implant 11 when the implant 11 is released. For the detachment direction, reference should be made to the discussions and definitions in the introductory description . In the example shown in Fig. 1, the chamfers 15 are inclined in the distal direction (from right to left in Fig. 1) . In other words, the distance of the sliding surface 14 from the wire 10 increases in the distal direction. The chamfers 15 or the sliding surfaces 14 form substantially straight surfaces and act as start ramps on which the implant 11, specifically its mesh structure, can slide if an overlap of the implant 11 with the engaging elements 12 occurs during release. The wire 10 can therefore be drawn further in a proximal direction without the implant 11 blocking the movement. Furthermore, the implant 11 is pushed radially outwards by the inclined sliding surfaces 14 and is freed from the engaging element 12. As can be seen in Fig. 12, the entire proximal end face of the engaging element 12, i.e., including the inner ring 20 on which the projections 13 are disposed, is inclined. The engaging element 12 therefore has a conical profile at the proximal axial end with correspondingly inclined projections 13. The profile can also be described as being frustoconical. The sliding surface 14 here begins at the level of the wire 10 and continues to the outer edge of the respective projection 13, which is formed on the outer diameter of the conical profile. The engaging element 12 continues, connecting to the conical profile with a cylindrical body (inner ring 20) and to the toothed outer profile as can be seen in Figures 1 and 12. The sliding surface 14 has at least two sections, a first common sliding surface section 14a in the region of the end face of the inner ring 20 and a second sliding surface section 14b, which forms the transition from the inner ring 20 to the projection 13. Both sections 14a and 14b merge with each other. The projections 13 and sliding surface 14 can be constructed in one piece, as can be seen in Figured. 1 and 12. Alternatively, the engaging element 12 can be constructed in two parts. The first common sliding surface section 14a can be constructed as a separate sleeve which rests on the end face of the inner ring 20. The transition between the two sections 14a, 14b corresponds to Fig. 12. Alternatively, only the proximal end face of the projection 13 may be constructed as a sliding surface 14. The sliding surface 14 is located at the base of the projection 13, i.e., at the outer diameter of the inner ring 20. The end face of the inner ring 20 is vertical. It is also possible for the sliding surface 14 to end below the upper edge or radially outer edge of the projection 13. The exemplary embodiment shown in Figures 2, 3 and 4 is constructed in a similar manner to the exemplary embodiment shown in Figures 1 and 2. The main difference is that the sliding surfaces 14 in the exemplary embodiment according to Figures 2, 3 and 4 are curved, as is also the case in Fig. 13, but the curvature is different. The other features of the aforementioned exemplary embodiment according to Figures 1 and 2 are applicable to the engaging element 12. Specifically, the entire engaging element 12 is curved in the axial direction of the implant 11. The proximal front side of the engaging element 12 is convexly curved. During manufacture, the engaging element is cut laterally, in particular laser cut, from a tube or hollow cylinder. The convex curvature results from the outer diameter of the tube. The opposing concave curvature of the engaging element on its distal side results from the inner diameter of the tube. The engaging means or projections are also cut laterally from the tube or hollow cylinder. The convex curvature can clearly be seen in Fig. 13. The manufacture and orientation of the projections 13 or vanes give rise to different degrees of curvature. The upper projection 13 in Fig. 13 is the most curved. This has a sharp edge on the distal side, which is ablated in order to form a counter-chamfer 21. The other two, less strongly curved projections 13 do not require a counterchamfer . Alternatively, the engaging element 12 can be formed as a convex disk or a segment of a hollow sphere which is uniformly curved about the central point with a radius r. This results in a uniform outer curvature of the engaging element 12, which forms the curved sliding surface 14. The projections 13 are provided on the outer diameter of the engaging element 12, as in the preceding exemplary embodiments, and form the engaging means required for anchoring the implant 11. The outer curvature of the engaging element 12 continues smoothly in the region of the projections 13, so that here again, the desired curved sliding surfaces 14 are formed. The exemplary embodiment according to Fig. 3 shows how the engaging element 12 can be used for different types of connection. In the example shown in Fig. 3, the engaging element 12 is combined with a stop 17, which is disposed proximally to the engaging element 12 and serves to push the implant 11 in the distal direction in the catheter or to keep the implant 11 stationary when the catheter is retracted. A free space 18 is formed between the engaging element 12 and the stop 17, in which, for example, radiographic markers are disposed, which are provided at the proximal end of the implant 11 and are used as a locking means in addition to the positioning of the implant. Other types of connection are possible. As an example, the curved engaging element 12 according to Fig. 2, 3, 4 and 13 can be used as a double connection for a network or, in general, as a mesh structure for the implant 11, as in the example according to Fig. 1. Figures 5, 6 and 7 show various exemplary embodiments of an engaging element 12, in particular a sleeve-shaped engaging element 12 with a plurality of projections 13, which respectively form an engaging section 19, 19a, 19b, 19c. The engaging sections 19, 19a, 19b, 19c form contiguous rings which are disposed axially one behind the other along the longitudinal axis of the engaging element 12. The projections 13 of the respective engaging sections 19, 19a, 19b, 19c are disposed in a manner which is offset in the circumferential direction. This results in a particularly reliable lock and uniform transmission of forces to the implant 11. In the example according to Fig. 5, three engaging sections 19a, 19b, 19c are provided, which are disposed one behind the other in the longitudinal direction of the implant 11. The projections 13 of each engaging section 19a, 19b, 19c are disposed in a manner which is offset in the circumferential direction of the engaging element 12 with respect to the projections 13 of the other two engaging sections 19a, 19b, 19c. The exemplary embodiments shown in Figures 5, 6 and 7 have in common that the projections 13 of the first engaging section 19a have sliding surfaces 14 in the proximal direction and the projections 13 of the second engaging section 19b have sliding surfaces 14 in the distal direction. The first and second engaging sections 19a, 19b are disposed at the proximal or distal ends of the engaging element 12. The respective sliding surfaces 14 on the projections 13 of the first and second engaging sections 19a, 19b thus form the axially outer contact surfaces which come into contact with the implant, specifically with the mesh structure of the implant. This ensures that the implant can move in both axial directions on the gliding surfaces 14, i.e. in the proximal and distal directions. In other words, the wire 10 and, together with it, the engaging element 12 can be moved both in the proximal direction as well as in the distal direction in order to push the implant radially outwards on the gliding surfaces 14. In the example according to Fig. 5, the inwardly-facing end faces of the projections 13, which are opposite the sliding surfaces 14, are disposed perpendicular to the wire 10. This is not a problem, because the respective opposing sliding surfaces 14 are inclined and thus allow the implant to be lifted from the engaging element 12. In the example shown in Fig. 5, a third engaging section 19c is provided which is disposed between the first and second engaging sections 19a, 19b. The projections 13 of the third engaging section 19c have vertical end faces, i.e. no sliding surfaces 14. Furthermore, the projections 13 of the third engaging section 19c are shorter in the axial direction than the projections 13 of the first and second engaging sections 19a, 19b, specifically shorter by approximately the longitudinal component of the sliding surface 14. This ensures that the detachment function is provided (with an approximately constant mesh structure of the implant 11), as discussed hereinabove for the inner end faces. In the example shown in Fig. 5, the sliding surfaces 14 are constructed as straight chamfers 15. A similar exemplary embodiment is shown in Fig. 7. Here again, three engaging sections 19a, 19b, 19c are provided, in which the projections 13 are offset with respect to each other. However, in this case, only the projections of the central, third engaging section 19c are offset with respect to the other two engaging sections 19a, 19b, which in turn are aligned with each other. A further difference is that the sliding surfaces 14 are formed as a combination of straight chamfers 15 and curved sections. The projections 13 are formed in the shape of hills with a straight plateau. The exemplary embodiment according to Fig. 6 has two engaging sections 19a, 19b, i.e. exactly two engaging sections 19a, 19b. In contrast to the example according to Fig. 5, each projection 13 has a sliding surface 14 on both end faces, i.e., both proximally as well as distally. The sliding surfaces 14 are constructed in the shape of chamfers 15. Here again, the advantage is that the engaging element 12 can be moved in both axial directions in order to detach the implant. The engaging elements 12 of Figures 5, 6 and 7 can, for example, be manufactured by mechanical processing such as milling, laser material processing or by additive manufacturing processes such as 3D printing, for example. A further exemplary embodiment which can be manufactured in a particularly versatile manner is shown in Figures 8 and 9 . In this exemplary embodiment, the sliding surfaces 14 are formed by a shrink tube 16 which encases the engaging element 12 in the circumferential direction and in the axial direction. The engaging element 12 may have a ring which is known per se or a sleeve which is known per se, with engaging means which in themselves have vertical end faces. The engaging means can be constructed as described in the prior art. The engaging means function as a core for the shrink tube 16 and together with it form the projections 13. The engaging means can also be referred to as the engaging profile core. The outer contour of the engaging element 12 required for the desired effect is determined by the shape of the shrink tube 16. The engaging means or the engaging profile under the shrink tube 16 stabilizes the latter and is responsible for the rough contour of the engaging element 12. The shape of the outer contour in the axial direction of the implant 11 can be set by the preconditioned shrink tube 16 and the heat treatment in a manner such that the sliding surfaces 14 have the desired inclination or curvature. This is shown in Figures 8 and 9. It should be understood that the sliding surfaces 14 of the shrink tube 16 are less precisely geometrically definable than, for example, a chamfer according to Fig. 1. In contrast to the vertical end face, however, it forms a smooth transition from the wire 10 to the upper side of the projection 13 by means of the shrink tube 16, which serves as the sliding surface 14. The sliding surface 14 of the shrink tube 16 can also be considered to be inclined and / or curved in the sense that no geometrically exact inclination or curvature is required, but rather a freeform surface which deviates from the vertical end face of the projection, which functionally serves as a start ramp for the mesh structure of the implant 11. Preferably, the shrink tube 16 is adapted to the lateral contour of the engaging means or core, i.e. it lies somewhat tighter there than at the end faces where the sliding surfaces 14 are formed. As shown in Fig. 9, the shrink tube 16 may encase a plurality of engaging elements 12 or one engaging element 12 and one stop 17 (Fig. 3). In the latter example, a free space 18 is provided for the accommodation of radiographic markers. Other types of connection are also possible here. Instead of the heat shrink tube, a flexible tube, for example a polymer tube, may be used. The exemplary embodiments according to Figures 1 to 9 described above have in common that the detachment direction extends in the longitudinal direction of the implant 11. In contrast, the examples according to Figures 10 and 11 show another exemplary embodiment of the invention in which the detachment direction, at least the initial detachment direction, is in the circumferential direction of the implant 11. In the example shown in Figures 10 and 11, the implant 11 is shown in cross-section (highly diagrammatic). The sliding surface 14 is inclined and / or curved in the circumferential direction of the implant 11. In the case of a plurality of projections, as shown in Fig. 10, the sliding surface 14 of the respective projections 13 is inclined and / or curved in the circumferential direction of the implant 11. The orientation of the respective sliding surfaces 14 is in the same circumferential direction, i.e. clockwise or counterclockwise. In the example shown in Figures 10 and 11, the sliding surfaces 14 are orientated counterclockwise. The sliding surfaces 14 are constructed as chamfers 15. Other shapes for the sliding surfaces 14, for example curved sliding surfaces 14 or spirally-shaped sliding surfaces 14, are possible. The engaging element 12 is connected to the wire 10 in a manner which is fixed against rotation. To actuate the engaging element 12, a torque is introduced into the engaging element 12 via the wire 10, which engaging element rotating with the wire 10, as can be seen in Fig. 11. The rotation of the engaging element 12 causes the sliding surfaces 14 to move relative to the implant 11, specifically relative to the mesh structure. This causes the implant 11 to be pushed radially outwards and lifted wherein, because of the mesh structure, the implant as a whole is lifted. As soon as the implant 11 has lifted sufficiently, the wire 10, together with the engaging element 12, is drawn out of the implant 11 in the proximal direction. The assembly according to the examples discussed above is used with a catheter as follows. The implant 11 is released by an axial relative movement between the catheter and the implant. There are different ways to accomplish this. As an example, at the treatment site, the catheter can be retracted in the proximal direction until the implant 11 exits the catheter. The wire 10 keeps the implant 11 stationary at the desired position. Alternatively, the catheter can be stationary and the implant is gently pushed out of the catheter in the distal direction using the wire. Here, the implant 11 self-deploys or self-expands successively in a proximal direction as the release progresses. When the implant 11 expands in the region of the engaging element 12, the implant 11 is freed from the wire 12 by the radial expansion and is separated from the engaging element 12. If the separation is not complete and the implant 11 and the engaging element 12 overlap, in the examples shown in Figures 1 to 9, the implant 11 is pushed radially outwards by the sliding surfaces 14 by means of a movement of the wire 10 in the proximal direction. The wire 10 will be freed in a reliable manner. In the examples according to Figures 10 and 11, the wire 10 and the engaging element 12 are rotated so that the implant is pushed outwards from the sliding surfaces 14. Here again, then, the wire 10 can be retracted. The implant is completely released and positioned at the desired location within the vessel to be treated. List of reference symbols 10 wire (transport wire) 11 implant 12 engaging element (sleeve) 13 projection 14 sliding surface 14a first sliding surface section 14b second sliding surface section 15 chamfer 16 shrink tube 17 stop 18 free space 19 engaging section 19a first engaging section 19b second engaging section 19c third engaging section 20 inner ring 21 counter-chamfer
Claims
1. An assembly for delivering a medical implant into a hollow organ of the body, with a wire (10) and a compressible and expandable medical implant (11) which is tubular in construction, - wherein, in the compressed state, the implant(11) is detachably connected to the wire (10) by at least one engaging element (12) for the transmission of force in the axial direction, wherein the engaging element (12) has at least one projection (13) which extends radially outwards and engages in the implant (11), and- wherein, in the at least partially expandedstate, the implant (11) can be released in a detachment direction by a relative movement between the engaging element (12) and the implant (11) , characterized in thatthe engaging element (12) has at least one sliding surface (14) which is inclined and / or curved in the detachment direction and which cooperates with the projection (13) in order to release the implant (11).
2. The assembly as claimed in claim 1, characterized in that the sliding surface (14) is inclined and / or curved in the longitudinal direction of the implant (11), in particular in the distal longitudinal direction.
3. The assembly as claimed in claim 1 or claim 2, characterized in that the inclined sliding surface (14) comprises a chamfer (15) which is formed in at least the region of the outer edge of the projection (13) .
4. The assembly as claimed in claim 3,characterized in thatthe chamfer (15) starts at (13) .the base of the projection5. The assembly as claimed in one of the preceding claims , characterized in that at least at one axial end, the engaging element (12) has a conical profile with the corresponding inclined projection (13), the axial end forming the inclined sliding surface (14) .
6. The assembly as claimed in claim 1 or claim 2, characterized in that the engaging element (12) is curved in the axial direction of the implant (11), wherein the projection (13) is formed with a corresponding curvature on the outer curve of the engaging element (12) and forms the curved sliding surface (14) .
7. The assembly as claimed in claim 1 or claim 2, characterized in that the inclined and / or curved sliding surface (14) comprises a tube, in particular shrink tube (16), which encases the engaging element (12).
8. The assembly as claimed in one of the preceding claims , characterized in thatthe sliding surface (14) is inclined and / or curved in the circumferential direction of the implant (11).
9. The assembly as claimed in one of the preceding claims , characterized in thata plurality of, in particular two, engaging elements (12), each with at least one sliding surface (14),are disposed in a manner which is axially spaced apart from each other in the longitudinal direction of the wire (10), wherein the sliding surfaces (14) are orientated in the same direction.
10. The assembly as claimed in one of claims 1 to 9, characterized in that a proximal stop (17) is associated with the engaging element (12), which is disposed in a manner which is axially spaced from the engaging element (12) in the longitudinal direction of the wire (10), with the formation of a free space (18).
11. The assembly as claimed in one of the preceding claims , characterized in that the engaging element (12) has a plurality of projections (13) which are disposed on the circumference of the engaging element (12) in a distributed manner, each having at least one sliding surface (14) and forming an engaging section (19) .
12. The assembly as claimed in claim 11, characterized in that the engaging element (12) has a plurality of engaging sections (19a, 19b, 19c) in the longitudinaldirection of the wire (10), wherein the projections (13) of the different engaging sections (19a, 19b,19c) are disposed in a manner which is offset in the circumferential direction.
13. The assembly as claimed in claim 11 or claim 12 characterized in that the projections (13) of a first engaging section (19a) have sliding surfaces (14) in at least the proximal direction and the projections (13) of asecond engaging section (19b) have sliding surfaces (14) in at least the distal direction.
14. A wire for delivering a tubular medical implant (11) into a hollow organ of the body, with at least one engaging element (12), wherein the implant (11) is compressible and expandable, - wherein, in the compressed state, the implant(11) is connectable to the wire (10) by the engaging element (12) for the transmission of force in the axial direction, wherein the engaging element (12) has at least one projection (13) which extends radially outwards and engages in the implant (11) when in use, and- wherein, in the at least partially expandedstate, the implant (11) can be released in a detachment direction by a relative movement between the engaging element (12) and the implant (11) , characterized in thatthe projection (13) has at least one sliding surface (14) which is inclined and / or curved in the detachment direction for releasing the implant (11).
15. A catheter with an assembly as claimed in claim 1.