Arrangement for delivering a medical implant, wire and catheter

Abstract

1. Arrangement for delivering a medical implant into a hollow body organ, comprising a wire (10) and a compressible and expandable medical implant (11) which is tubular in shape, - wherein the implant (11) in the compressed state is detachably connected to the wire (10) by at least one engagement element (12) for transmitting force in the axial direction, wherein the engagement element (12) has at least one projection (13) which extends radially outwards and engages the implant (11), and - wherein the implant (11) in the at least partially expanded state can be released by a relative movement between the engagement element (12) and the implant (11) in a release direction, characterized in that the engagement element (12) has at least one sliding surface (14) which is inclined and / or curved in the release direction and cooperates with the projection (13) to release the implant (11).

Description

The invention relates to an arrangement for feeding a medical implant into a hollow body organ with a wire and a compressible and expandable medical implant which is configured in the form of a tube. The implant is releasably connected to the wire in the compressed state by at least one engagement element for transmitting force in the axial direction, wherein the engagement element has at least one projection which extends radially outwards and engages with the implant. The implant can be released in the at least partially expanded state by a relative movement between the engagement element and the implant in a release direction. The invention further relates to a wire for feeding a medical implant into a hollow body organ and a catheter.The arrangement mentioned at the beginning is known, for example, from WO 2013 / 107783 A1, which is assigned to the assignee of the present invention. A wire having the features of the preamble of claim 14 is also known from this prior art.This arrangement or this wire has proven to be extremely successful in practice and enables the safe supply of an implant, such as a stent or a flow diverter, through a catheter to the treatment site. Upon release from the catheter, the implant is uncoupled from the wire and remains at the treatment site. The wire is withdrawn through the catheter.The implant is released by a relative movement in the axial direction between catheter and implant at the treatment site. The implant emerging from the catheter unfolds or expands, wherein the expansion movement with increasing release successively proceeds in the proximal direction of the implant. When the implant expands in the region of the engagement element, the implant is released from the wire by the radially outward movement and the implant and the engagement element are separated. The implant is fully released and expanded in the vessel to be treated at the desired location.If the radial outward movement of the implant is restricted, for example, by patient-specific vessel properties in the region of the treatment site, such that the radial distance between implant and engagement element is small, the release of the implant can be made more difficult.The object of the invention is therefore to improve the known arrangement to the extent that the implant can be released as safely as possible even under difficult conditions. The invention is also based on the object of specifying a corresponding wire and a catheter.According to the invention, the object is achieved with regard to the arrangement by the subject matter of claim 1, with regard to the wire by the subject matter of claim 14 and with regard to the catheter by the subject matter of claim 15.Specifically, the object is achieved by an arrangement for feeding a medical implant into a hollow body organ with a wire and a compressible and expandable medical implant which is configured in the form of a tube. The implant is releasably connected to the wire in the compressed state by at least one engagement element for transmitting force in the axial direction. The engagement element has at least one protrusion that extends radially outward and engages the implant. The implant can be released in the at least partially expanded state by a relative movement between the engagement element and the implant in a release direction. According to the invention, the engagement element has at least one sliding surface which is inclined and / or curved in the release direction. The sliding surface interacts with the projection for releasing the implant.The invention has the advantage that the engaging element and the implant can be released securely 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, thereby assisting in decoupling the implant from the wire. Hooking of the implant to the engagement element is avoided and the wire can be safely withdrawn into the catheter. This is achieved by the inclined and / or curved sliding surface.The sliding surface interacts with the projection for releasing the implant. The sliding surface is therefore suitable or adapted to support the release of the implant. Advantageously, the sliding surface and the projection are formed in one 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 arranged axially directly behind one another, other embodiments being possible.The projection and the slide surface cooperate in that the slide surface acts or at least helps to bring the implant to the height required to overcome the projection. The elevation may, but need not be, the radially outer surface of the protrusion. The sliding surface and the projection are arranged in the axial direction of the implant or of the wire in such a way that a transition of movement of the implant is possible, for example if the sliding surface and the projection are connected or can be connected, so that the sliding surface directly merges into the projection. Other embodiments are possible.Due to the inclination and / or curvature, the sliding surface extends deviating from a perpendicular side of the projection. Since the inclination direction or curvature direction runs in the release direction, the release operation is supported by the sliding surface.The release direction is the direction in which the implant is released by the relative movement between the engagement element or wire and the implant. If, for example, the wire is pulled back into the catheter in the proximal direction when the implant is stationary, the release direction of the implant runs in the distal direction. The implant is proximal from the catheter tip prior to release and distal from the catheter tip after release. The sliding surface is then likewise oriented in the distal direction, so that the implant can slide on the sliding surface during a movement of the engagement element in the proximal direction.The releasing direction is not limited to the longitudinal direction of the implant.Rather, the disengagement direction generally refers to the relative movement between the engagement member and the implant that occurs in addition to the expansion movement of the implant to disengage the implant and the engagement member in the radial direction. The release 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 even allows the implant to be decoupled from the wire even in a partially expanded state, in which the implant and the engagement element overlap, i.e. are still in partial engagement. This is achieved in that the sliding surface is inclined and / or curved in the release direction. When the wire is retracted proximally into the catheter, the implant slides on the slide surface and is forced radially outward. The implant is thus released from the wire.The mechanism described above for the partially expanded partially engaged state applies equally to a partially expanded state in which the radial distance between the engaging element and the implant is so small that it can engage during release.The invention is suitable for self-expandable medical implants. The medical implant of the arrangement can therefore be self-expandable. Such implants are known and are usually made of a shape memory material.The implant can preferably have a lattice structure, in particular a tubular wall made of a lattice structure.The mesh structure may be a braid of braided filaments or wires or of a braided single filament or single wire. The braid forms meshes. The grating structure can also be a monolithic grating structure made of webs, for example a laser-cut grating structure. The monolithic lattice structure forms cells.The invention is not limited to a particular type of intervention. The wire may be connected to the implant in various ways. For example, the engagement element can engage in the grid structure. It is also possible for the engagement element to be detachably connected to end loops or end meshes or end diamonds of the implant. Releasable connections between the implant and the engagement element can also be provided by additional components, in particular X-ray markers. These can be, for example, crimped marker wires.The engagement element may have a plurality of projections. The projections each cooperate with a sliding surface for releasing the implant.The implant and wire assembly of the present invention is treated as an assembly disclosed and claimed independently of the catheter which transports the assembly to the treatment site. In addition, the combination of a catheter and the assembly of the invention is also disclosed and claimed. The invention further discloses and claims the wire for feeding the medical implant as such, i.e. without implant and without catheter. The wire is suitable for achieving the advantages explained above in connection with the delivery of an implant and for this purpose has an engagement element modified according to the invention, which is described above. Such a wire is also referred to as a transport wire.Preferred embodiments of the invention are claimed or indicated in the dependent claims.Thus, the sliding surface can 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 release direction runs parallel to the wire. Thus, during a relative movement between the axially moved wire and the stationary implant, the wire can be pulled back into the catheter. This corresponds to the usual loosening process when the implant is anchored in a fixed position at the treatment site and the wire is pulled back in the proximal direction. The inclination of the sliding surface in the distal longitudinal direction means that a spatial component of the sliding surface runs in the distal direction. This is not the case with a surface orthogonal to the longitudinal axis of the wire. When the wire with the engagement element is pulled in proximal direction, the sliding surface moves relative to the implant, so that a relative movement occurs between the engagement element and the implant, whereby the engagement element and the implant are released from each other or a renewed unintentional engagement does not occur.Preferably, the inclined sliding surface comprises a chamfer which is formed at least in the region of the outer edge of the projection. The chamfer can be produced easily since only the outer edge of the projection has to be machined. It is not necessary to machine the entire side of the protrusion. It is sufficient if a part of the projection is provided with the chamfer or chamfered, namely in the region of the outer edge of the projection, i.e. where it can become hooked with the implant, if the distance between the engagement element and the implant is not sufficiently large.In a further embodiment, the chamfer can be attached to the foot of the projection. The chamfer thus extends over the entire side of the projection. This has the advantage that a maximum length of sliding surface is formed. The safety against jamming is increased.The engagement element may have at least at one axial end a conical profile with the correspondingly inclined projection forming the inclined sliding surface. This embodiment has the advantage that the engagement element together with the projection is inclined, so that practically no edges are formed in the release direction, which could impede the decoupling. This minimizes the risk of jamming. The projection and thus the sliding surface are part of the conical jacket of the engagement element and therefore inclined in accordance with the conicity of the axial end of the engagement element.In a further preferred embodiment, the engagement element is curved in the axial direction of the implant, in particular in the distal direction of the implant, wherein the projection on the outer curvature of the engagement element is formed with a corresponding curvature and forms the curved sliding surface. This means that the entire engagement element together with the projection is curved and therefore likewise does not have any edges which could impede the release process. This minimizes the risk of jamming. The protrusion is part of the curved engagement element and therefore also correspondingly curved. The engagement element can be cut from a tube, for example, and can be profiled accordingly.In a further particularly preferred embodiment, the inclined and / or curved sliding surface comprises a hose which envelopes the engagement element. This embodiment has the advantage of particularly simple and flexible production. Mechanical machining of the engagement element is not necessary. The hose can be, for example, a flexible hose or a shrink hose.The sliding surface is thus produced by an additional element, namely the hose, which is arranged above an engagement profile core and surrounds the latter. The hose together with the engagement profile core forms the engagement element, specifically the projection or the projections with the sliding surface. The wrapped engagement profile core is the core of the hose and stabilizes it. The outer contour of the engagement element is determined by the shape of the hose.For the engagement profile core, it is possible to resort to engagement elements known per se, which are modified by the combination with the hose such that a projection or projections (depending on the engagement profile core) are produced, which have sliding surfaces inclined and / or curved by the hose. The production is therefore simple and can be carried out flexibly with known engagement elements.The hose surrounds the engagement element in a geometrically undefined manner. It is substantially adapted to the contour of the engagement element, i.e. it does not directly follow the contour and does not closely abut on the engagement element. Outer edges of the engagement element are covered by the hose, which forms a rounded sliding surface or a rounded sliding surface section there. In the radially outer region of the engagement element, the hose bears more closely against the contour than in the radially inner region. The hose thus images the coarse contour of the engagement element. The sliding surface forms a flowing or continuous transition from radially inside to radially outside.If a plurality of engagement elements are arranged on the circumference of the wire, the tube follows the height profile formed thereby in the circumferential direction in such a way that the engagement elements can engage in the implant, for example in the lattice structure.The hose forms the inclined and / or curved sliding surface in that the hose extends substantially obliquely deviating from the perpendicular relative to the tube shape of the implant or deviating from the perpendicular flank or side of the engagement profile core. In sections, the hose can be inclined and curved to different extents. In the overall extension in the release direction, the tube forms an oblique free-form surface for releasing the implant. The free-form surface acts as a sliding surface.In contrast thereto, the chamfer forms a geometrically defined, in particular straight, sliding surface which is inclined. The basic idea is the same as in the case of the chamfer or in the curved shape of the engagement element, namely to support the release process between the implant and the wire by the orientation of the sliding surface deviating from the perpendicular.The tube may be flexible or compliant, for example a polymeric tube. Due to the flexibility, the hose stretches over the engagement profile core. The flexible hose thus adapts to its coarse contour. Alternatively, the hose can be a shrink hose which stretches over the engagement profile core by a heat treatment or other treatment and thus adapts itself to its rough contour.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 release process is actively assisted by rotating the wire. The rotation of the wire results in a relative movement between the implant and the engagement element in the circumferential direction. The implant slides in the circumferential direction on the sliding surface and is pressed radially outwards by the latter due to the inclination or curvature. If the distance between the implant and the engagement element is too small due to an insufficient expansion movement and an overlap occurs, the physician can force the decoupling by rotating the wire. When the implant and wire are disengaged from the rotation, the wire can be retracted proximally into the catheter, as is usual.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. For example, the sliding surface can be arranged spirally with increasing diameter. This results in a screwing action in which the engagement element rotates and at the same time carries out a feed movement relative to the implant. The height position of the implant and simultaneously the relative position between the wire and the implant in the axial direction are changed.In a further embodiment, it is possible that a plurality of, in particular two, engagement elements are each arranged with at least one sliding surface axially spaced apart from one another in the longitudinal direction of the wire, wherein the sliding surfaces of the engagement elements are oriented in the same direction. This increases the safety when coupling the implant to the wire by the multiple connection. The dissolution functionality is retained in this case. For this purpose, the sliding surfaces are provided on both engagement elements and oriented in the same direction, so that these support the release process during a relative movement between the wire and the implant in the same direction.The engagement element can be assigned a proximal stop (also called a pushing sleeve), which is arranged at an axial distance from the engagement element in the longitudinal direction of the wire, forming a free space. This basic structure of the arrangement is designed to accommodate an additional component, for example an X-ray marker, and is described in the aforementioned prior art publication, with the difference, however, that the engagement element is modified in the present case 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 engagement element has a plurality of projections which are arranged distributed over the circumference of the engagement element, each have at least one sliding surface and form an engagement portion. This improves the safety of the connection and achieves a uniform transmission of force from the wire to the implant over the circumference of the engagement element. The sliding surfaces of the projections are each oriented in the same direction. This does not exclude the provision of further sliding surfaces which are oriented in other directions.The engagement element can have a plurality of engagement sections in the longitudinal direction of the wire, wherein the projections of the different engagement sections are arranged offset in the circumferential direction. As a result, both the coupling safety due to the increased number of projections and the uniform force transmission are improved because the projections of the different engagement sections are arranged offset in the circumferential direction.The projections of a first engagement section can have sliding surfaces at least in the proximal direction and the projections of a second engagement section can have sliding surfaces at least in the distal direction. The engagement element therefore enables a releasing operation in both axial directions. This can be advantageous if the decoupling of the implant is to be supported particularly strongly by an axial movement of the wire and thus of the engagement element.In general, each projection engages in its own mesh or cell of the grid structure.The invention is explained in more detail below on the basis of exemplary embodiments with reference to the attached drawings. These show FIG. 1 shows a perspective view of an arrangement according to an exemplary embodiment of the invention with two engagement elements (without implant); FIG. 2 is a perspective view of an engagement element for an arrangement according to FIG. 3 ; FIG. 3 shows a view of an arrangement according to a further exemplary embodiment of the invention with an engagement element and a stop (without implant); FIG. 4 is a side view of the engagement element according to FIG. 3 ; FIG. 5 shows a perspective view of an engagement element of an arrangement according to a further exemplary embodiment of the invention, having a plurality of engagement sections; FIG. 6 shows a perspective view of an engagement element of an arrangement according to a further exemplary embodiment of the invention, having two engagement portions; FIG. 7 shows a perspective view of an engagement element of an arrangement according to a further exemplary embodiment of the invention with rounded sliding surfaces; FIG. 8 shows a perspective view of an arrangement according to a further exemplary embodiment of the invention with a stocking tube (without implant); FIG. 9 is a side view of an assembly with the engagement element of claim 8 (without implant); FIG. 10 shows a front view of an arrangement according to a further exemplary embodiment of the invention, in which the release direction runs in the circumferential direction of the implant; FIG. 11 shows the arrangement according to FIG. 10 during the release of the implant; FIG. 12 is a perspective view of an engagement element for an arrangement according to FIG. 1 ; and FIG. 13 is a perspective view of an engagement element for an arrangement according to FIG. 3 with a greater curvature than FIG. 2.FIG. 1 shows an exemplary embodiment according to the invention of an arrangement for feeding a medical implant 11 into a hollow body organ, which is suitable in particular, but not exclusively, for the treatment of neurovascular diseases, such as, for example, for the treatment of stroke.The assembly comprises a wire 10, which may also be referred to as a transport wire or a retention wire, and the implant 11. The assembly is disclosed and claimed in the application, as is the wire 10 without the implant 11.The implant 11 is tubular and compressible and expandable in a manner 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 achieved by the implant 11 being produced from a shape memory material, such as nitinol. 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 lattice structure. The grid structure can be designed as a braid or as a monolithic grid structure. In this regard, reference is made to the statements in the introduction to the specification of the application. Examples of such implants are stents or flow diverters. Other implants 11 are possible which can be detachably connected to the wire 10.The wire 10 is configured in a manner known per se and has, for example, coils which are arranged on a core (cf. 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. For this purpose, in the arrangement according to FIG. 1, a plurality of, specifically two, engagement elements 12 are provided, which engage in the lattice structure of the implant 11 in order to thus bring about a force transmission in the axial direction from the wire 10 to the implant 11. The connection between the wire 10 and the implant 11 is releasable to disengage the implant 11 from the wire 10 when the implant 11 is released from the catheter at the treatment site. The implant 11 can be released in the at least partially expanded state by a relative movement between the engagement elements 12 and the implant 11 in a release direction.The relative movement between the engagement elements 12 and the implant 11 is to be distinguished from the radial expansion of the implant 11 in which the implant 11 moves radially outwards. The implant 11 is first released from the wire 10 and its engagement element 12 by the radial expansion and then finally decoupled by a further movement of the wire 10 relative to the implant 11. The relative movement thus occurs when the wire 10 is moved relative to the implant. The relative movement takes place in the longitudinal direction of the implant and / or in the circumferential direction of the implant 11. In the examples according to FIGS. 1 to 9, the relative movement takes place in the longitudinal direction of the implant 11. This is explained in more detail below.In the following, the engagement element 12 or the two engagement elements 12 which are modified for the secure detachment from the implant 11 will be described in more detail with reference to FIGS. 1, 12.In FIG. 1, both engagement elements 12 are of substantially identical construction. Deviations are due to manufacturing engineering. Other combinations are possible. The following explanations apply to both engagement elements 12.The engagement element 12 is sleeve-shaped. This also applies to the exemplary embodiments according to FIGS. 3 to 11. The engagement element 12 has a central opening through which the wire 10, specifically the core of the wire 10, extends in the installed state. This can be seen easily in FIGS. 1, 3. The engagement element 12 can be rotatably or rotationally fixedly connected to the wire 10.The engagement element 12 has a plurality of, specifically three, projections 13 which extend radially outwards. The function of these projections 13 is to engage the implant 11, specifically the lattice structure of the implant 11, when the implant 11 is arranged on the wire 10 in the compressed state. The projections 13 can also be referred to as serrations of a crown, as noses, wings or as teeth. A different number of projections 13, in particular more than three projections 13, is possible.The projections 13 each have a sliding surface 14 in the form of a chamfer 15 which is inclined in the release direction. In the example according to FIG. 1, the sliding surfaces 14 of the two engagement elements 12 are inclined in the same direction.The release direction results from the relative movement between the engagement element 12 or the wire 10 and the implant 11 when the implant 11 is released. With regard to the direction of release, reference is made to the explanations and definitions in the introduction to the description.In the example according to 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 run-on slopes on which the implant 11, specifically its lattice structure, can slide if an overlap of the implant 11 with the engagement elements 12 should occur during release. The wire 10 can thus be pulled further in proximal direction without the implant blocking the movement. Rather, the implant 10 is urged radially outwards by the inclined sliding surfaces 14 and is released from the engagement element 12.As can be seen in FIG. 12, the entire proximal end face of the engagement element 12, i.e. also the inner ring 20 on which the projections 13 are arranged, is inclined. The engagement element 12 thus has a conical profile at the proximal axial end with correspondingly inclined projections 13. The profile can also be referred to as frustoconical. The sliding surface 14 begins at the height of the wire 10 and continues as far as the outer edge of the respective projection 13 which is formed on the outer diameter of the conical profile. The engagement element 12 continues, following the conical profile, with a cylindrical body (inner ring 20) and the toothed outer profile, as in Figures 1 and 12.The sliding surface 14 has at least two sections, a first common sliding surface section 14 ain the region of the end face of the inner ring 20 and a second sliding surface section 14 bwhich forms the transition from the inner ring 20 to the projection 13. Both sections 14 a, 14 bcross into one another.The projections 13 and sliding surface 14 can be formed in one piece, as can be seen in FIGS. 1, 12. Alternatively, the engagement element 12 can be formed in two parts. The first common sliding surface section 14 acan be formed as a separate sleeve which abuts the end face of the inner ring 20. The transition of the two sections 14 a, 14 bcorresponds to FIG. 12.Alternatively, only the proximal end face of the projection 13 can be designed as a sliding surface 14. The sliding surface 14 abuts the base of the projection 13, i.e. the outer diameter of the inner ring 20. The end face of the inner ring 20 is perpendicular.It is also possible for the sliding surface 14 to end below the upper edge or radial outer edge of the projection 13.The exemplary embodiment according to FIGS. 2, 3 and 4 is constructed similarly to the exemplary embodiment according to FIGS. 1 and 2. The main difference is that the sliding surfaces 14 in the embodiment according to FIGS. 2, 3 and 4 are curved, thus also in FIG. 13 with a different curvature. With regard to the engagement element 12, the other features of the above exemplary embodiment according to FIGS. 1 and 2 can be transferred.Specifically, the entire engagement element 12 is curved in the axial direction of the implant 11. The proximal front side of the engagement element 12 is convexly curved.During production, the engagement element is cut laterally from a tube or hollow cylinder, in particular laser-cut. The convex curvature results from the outside diameter of the tube. The concave curvature of the engagement element on its distal side arranged opposite is obtained from the inner diameter of the tube. The engagement means or projections are likewise cut laterally from the tube or hollow cylinder.The convex curvature is clearly visible in FIG. 13.The production and orientation of the projections 13 or wings result in different large curvatures.The upper projection 13 in Fig. 13 is most curved. On the distal side, this has a sharp edge which is ablated to form a counter chamfer 21. The other two, less strongly curved projections 13 do not require a counter chamfer.Alternatively, the engaging member 12 may be formed as a convex disk or a hollow spherical segment smoothly curved around the center with a radius r. This results in a uniform external curvature of the engagement element 12 which forms the curved sliding surface 14. As in the preceding exemplary embodiments, the projections 13 are provided on the outer diameter of the engagement element 12 and form the engagement means required for anchoring the implant 11. The external curvature of the engagement element 12 continues uniformly in the region of the projections 13, so that the desired curved sliding surfaces 14 are also formed there.The embodiment according to FIG. 3 shows how the engagement element 12 can be used for different connection types. In the example according to FIG. 3, the engagement element 12 is combined with a stop 17 which is arranged proximally of the engagement element 12 and serves to push the implant 11 in the distal direction in the catheter or to hold the implant 11 stationary when the catheter is retracted. Between the engagement element 12 and the stop 17 a free space 18 is formed in which, for example, X-ray markers are arranged, which are provided at the proximal end of the implant 11 and are used as locking means in addition to the positioning of the implant.Other types of connections are possible. For example, the curved engagement element 12 according to FIGS. 2, 3, 4 and 13 can be used as in the example according to FIG. 1 as a double connection for a braid or generally a lattice structure of the implant 11.FIGS. 5, 6 and 7 show various exemplary embodiments of an engagement element 12, in particular a sleeve-shaped engagement element 12 having a plurality of projections 13, which each form an engagement portion 19, 19 a, 19 b, 19 c. The engagement sections 19, 19 a, 19 b, 19 cform contiguous rings which are arranged axially one behind the other along the longitudinal axis of the engagement element 12.The protrusions 13 of the respective engaging portions 19, 19a, 19b, 19c are arranged offset in the circumferential direction. This achieves a particularly secure locking and uniform force transmission to the implant 11.In the example according to FIG. 5, three engagement sections 19 a, 19 b, 19 care provided, which are arranged one behind the other in the longitudinal direction of the implant 11. The projections 13 of each engagement portion 19 a, 19 b, 19 care arranged offset with respect to the projections 13 of the two other engagement portions 19 a, 19 b, 19 cin the circumferential direction of the engagement element 12.It is common to the exemplary embodiments according to FIGS. 5, 6 and 7 that the projections 13 of the first engagement section 19 ain the proximal direction have sliding surfaces 14 and the projections 13 of the second engagement section 19 bin the distal direction have sliding surfaces 14. The first and second engaging portions 19a, 19b are disposed at the proximal and distal ends of the engaging member 12, respectively.The respective sliding surfaces 14 on the projections 13 of the first and second engagement sections 19 a, 19 bthus form the axially outer contact surfaces which come into contact with the implant, specifically with the lattice structure of the implant. This ensures that the implant can move in both axial directions, i.e. in proximal and distal directions, on the sliding surfaces 14. In other words, the wire 10 and together with it the engagement element 12 can be moved both in proximal and in distal direction in order to press the implant radially outwards on the sliding surfaces 14.In the example of FIG. 5, the inwardly facing end surfaces of the projections 13 which are opposite the sliding surfaces 14 are arranged perpendicular to the wire 10. This is unproblematic because the respectively opposite sliding surfaces 14 are inclined and thus make it possible to lift the implant from the engagement element 12.In the example according to FIG. 5, a third engagement portion 19 cis provided, which is arranged between the first and second engagement portions 19 a, 19 b. The projections 13 of the third engagement section 19c have perpendicular end faces, i.e. no sliding surfaces 14. In addition, the projections 13 of the third engagement portion 19 care shorter in the axial direction than the projections 13 of the first and second engagement portions 19 a, 19 b,specifically, are shorter approximately by the longitudinal component of the sliding surface 14. This provides the release function (with an approximately constant lattice structure of the implant 11), as explained above for the inner end faces.In the example according to FIG. 5, the sliding surfaces 14 are designed as straight chamfers 15.A similar embodiment is shown in Fig. 7. There too, three engagement sections 19 a, 19 b, 19 care provided, in which the projections 13 are offset with respect to one another. However, only the projections of the middle third engagement section 19 care offset there from the other two engagement sections 19 a, 19 b, which in turn are aligned with one another. Another difference is that the sliding surfaces 14 are formed as a combination of straight chamfers 15 and curved portions. The protrusions 13 are formed in the shape of hills having a straight plateau.The exemplary embodiment according to FIG. 6 has two engagement portions 19 a, 19 b, i.e. exactly two engagement portions 19 a, 19 b. In contrast to the example according to FIG. 5, each projection 13 has a sliding surface 14 on both end sides, i.e. both proximally and distally. The sliding surfaces 14 are designed in the form of chamfers 15. Here too, there is the advantage that the engagement element 12 can be moved in both axial directions for releasing the implant.The engagement elements 12 of FIGS. 5, 6 and 7 can be produced, for example, by mechanical machining, such as milling, laser material machining, or by additive manufacturing methods, such as 3-D printing.A further exemplary embodiment is shown in FIGS. 8 and 9, which can be produced in a particularly flexible manner.In this exemplary embodiment, the sliding surfaces 14 are formed by a shrink tube 16 which envelopes the engagement element 12 in the circumferential direction and in the axial direction. The engagement element 12 can have a ring known per se or a sleeve known per se with engagement means which have vertical end faces taken per se. The engagement means can be formed as in the prior art. The engagement means function as a core for the shrink tube 16 and together with this form the projections 13.The external contour of the engagement element 12 required for the desired effect is determined by the shape of the shrink tube 16. The engagement means or the engagement profile under the shrink sleeve 16 stabilizes the latter and is responsible for the rough contour of the engagement element 12. The shape of the outer contour in the axial direction of the implant 11 can be adjusted by the preconditioned shrink tube 16 and the heat treatment such that the sliding surfaces 14 have the desired inclination or curvature. This is illustrated in FIGS. 8 and 9.It is understood that the sliding surfaces 14 in the shrink tube 16 can be defined geometrically less exactly than, for example, in the case of a chamfer according to FIG. 1, a smooth transition from the wire 10 to the upper side of the projection 13 is formed in any case in contrast to the perpendicular end face by the shrink tube 16, which serves as the sliding surface 14. The sliding surface 14 of the shrink tube 16 can also be considered as inclined and / or curved, namely in the sense that no geometrically exact inclination or curvature is required, but rather a free-form surface which deviates from the vertical end face of the projection and which functionally serves as a run-on slope for the lattice structure of the implant 11.The shrink tube 16 is preferably adapted to the lateral contour of the engagement means or core, i.e. it lies somewhat more closely there than on the end faces where the sliding surfaces 14 are formed.As shown in FIG. 9, the shrink tube 16 can wrap around a plurality of engagement elements 12 or an engagement element 12 and a stop 17 (FIG. 3 ). In the latter example, a free space 18 is provided for the recording of X-ray markers. Other types of connections are also possible here.Instead of the shrink tube, a flexible tube, for example a polymer tube, can be used.It is common to the above-described exemplary embodiments according to FIGS. 1 to 9 that the release direction runs in the longitudinal direction of the implant 11. In contrast, the examples according to FIGS. 10 and 11 show another exemplary embodiment of the invention, in which the release direction takes place in the circumferential direction of the implant 11, at least the initial release direction. In the example according to FIGS. 10 and 11, the implant 11 is shown in cross section (highly schematic).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 takes place in the same circumferential direction, i.e. in or counter-clockwise direction. In the example according to FIGS. 10 and 11, the orientation of the sliding surfaces 14 takes place counterclockwise.The sliding surfaces 14 are designed as chamfers 15. Other shapes of the sliding surfaces 14, for example curved sliding surfaces 14 or spiral sliding surfaces 14, are possible.The engagement element 12 is connected to the wire 10 in a rotationally fixed manner. To actuate the engagement element 12, a torque is introduced via the wire 10 into the engagement element 12, which rotates with the wire 10, as shown in FIG. 11. The rotation of the engagement element 12 ensures that the sliding surfaces 14 move relative to the implant 11, specifically relative to the lattice structure. The implant 11 is thereby pushed and raised radially outwards, wherein the lattice structure results in the implant being raised overall.Once the implant 11 has been sufficiently lifted, the wire 10 is pulled out of the implant 11 in the proximal direction together with the engagement element 12.The arrangement according to the examples explained above is used with a catheter as follows.The implant 11 is released by an axial relative movement between catheter and implant. There are various possibilities for this. For example, the catheter at the treatment site can be retracted in proximal direction until the implant 11 exits the catheter. The wire 10 holds the implant 11 in a fixed position at the desired location. Alternatively, the catheter may be stationary and the implant is gently pushed with the wire distally out of the catheter.In this case, the implant 11 expands or expands successively in the proximal direction with increasing release. When the implant 11 expands in the region of the engagement element 12, the implant 11 is released from the wire 12 by the radial expansion and is separated from the engagement element 12. If the separation does not take place completely and the implant 11 and the engagement element 12 overlap, the implant 11 in the examples according to FIGS. 1 to 9 is pressed radially outwards by the sliding surfaces 14 by a movement of the wire 10 in proximal direction. The wire 10 is reliably released. In the examples of Figures 10 and 11, the wire 10 and the engagement member 12 are rotated to force the implant outwardly from the slide surfaces 14. The wire 10 can then also be retracted here.The implant is fully released and positioned in the vessel to be treated at the desired location.List of reference characters10 Wire (transport wire) 11 Implant 12 Engagement element (sleeve) 13 Projection 14 Sliding surface 14 afirst sliding surface section 14 bsecond sliding surface section 15 Chamfer 16 Shrink tube 17 Stop 18 Free space 19 Engagement section 19 afirst engagement section 19 bsecond engagement section 19 cthird engagement section 20 Inner ring 21 Counter chamferReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedWO 2013 / 107783 A1

[0002]

Claims

Arrangement for feeding a medical implant into a hollow body organ, comprising a wire (10) and a compressible and expandable medical implant (11) which is tube-shaped, - wherein the implant (11) in the compressed state is detachably connected to the wire (10) by at least one engagement element (12) for force transmission in the axial direction, wherein the engagement element (12) has at least one projection (13) which extends radially outwards and engages into the implant (11), and - wherein the implant (11) in the at least partially expanded state can be released by a relative movement between the engagement element (12) and the implant (11) in a release direction, characterized in that the engagement element (12) has at least one sliding surface (14) which is inclined and / or curved in the release direction and interacts with the projection (13) for releasing the implant (11).Arrangement according to claim 1 characterised 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.Arrangement according to claim 1 or 2, characterised in that the inclined sliding surface (14) comprises a chamfer (15) which is formed at least in the region of the outer edge () of the projection (13).Arrangement according to claim 3 characterised in that the chamfer (15) abuts the foot of the projection (13).Arrangement according to any of the preceding claims, characterized in that the engagement element (12) has, at least at one axial end, a conical profile with the correspondingly inclined projection (13) forming the inclined sliding surface (14).Arrangement according to claim 1 or 2, characterised in that the engagement element (12) is curved in the axial direction of the implant (11), wherein the protrusion (13) is formed on the outer curvature of the engagement element (12) with a corresponding curvature and forms the curved sliding surface (14).Arrangement according to claim 1 or 2, characterised in that the inclined and / or curved sliding surface (14) comprises a hose, in particular shrink hose (16), which envelopes the engagement element.Arrangement according to one of the preceding claims, characterized in that the sliding surface (14) is inclined and / or curved in the circumferential direction of the implant (11).Arrangement according to one of the preceding claims, characterized in that a plurality of, in particular two, engagement elements (12) are each arranged with at least one sliding surface (14) spaced apart axially from one another in the longitudinal direction of the wire (10), wherein the sliding surfaces (14) are oriented in the same direction.Arrangement according to one of Claims 1 to 9da, characterized in that the engagement element (12) is assigned a proximal stop (17), which is arranged at an axial distance from the engagement element (12) in the longitudinal direction of the wire (10), forming a free space (18).Arrangement according to one of the preceding claims, characterized in that the engagement element (12) has a plurality of projections (13) which are arranged distributed over the circumference of the engagement element (12), each have at least one sliding surface (14) and form an engagement portion (19).Arrangement according to claim 11 characterised in that the engagement element (12) has a plurality of engagement portions (19a, 19b, 19c) in the longitudinal direction of the wire (10), wherein the projections (13) of the different engagement portions (19a, 19b, 19c) are arranged offset in the circumferential direction.Arrangement according to claim 11 or 12 characterised in that the projections (13) of a first engagement section (19a) have sliding surfaces (14) at least in the proximal direction and the projections (13) of a second engagement section (19b) have sliding surfaces (14) at least in the distal direction.Wire for feeding a tubular, medical implant (11) into a hollow organ of the body, having at least one engagement element (12), wherein the implant (11) is compressible and expandable, - wherein the implant (11) in the compressed state can be connected to the wire (10) by the engagement element (12) for the transmission of force in the axial direction, wherein the engagement element (12) has at least one projection (13) which extends radially outwards and engages in the implant (11) during use, and - wherein the implant (11) in the at least partially expanded state can be released by a relative movement between the engagement element (12) and the implant (11) in a release direction, characterized in that the projection (13) has at least one sliding surface (14) for releasing the implant (11), which sliding surface is inclined and / or curved in the release direction.A catheter having an assembly according to claim 1.

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