WO2010097235A1

WO2010097235A1 - Medical implant having a grid structure, medical device, method for the production thereof and method for introducing the medical implant into a delivery system

Info

Publication number: WO2010097235A1
Application number: PCT/EP2010/001213
Authority: WO
Inventors: Giorgio Cattaneo
Original assignee: Acandis Gmbh & Co.Kg
Priority date: 2009-02-26
Filing date: 2010-02-26
Publication date: 2010-09-02
Also published as: DE102009010825A1; DE102009010825B4; WO2010097235A9

Abstract

The invention relates to a medical implant having a grid structure (10), which comprises grid webs (11) and can be transferred into a compressed state I for introducing it into a delivery system and into an expanded state II for implanting it, wherein the grid webs (11) each have a longitudinal extension (11a) and a transverse extension (11b). The invention is characterized in that the grid webs (11) can be folded along the longitudinal extensions (11a) thereof such that they are folded in the compressed state I and deployed in the expanded state II, wherein the transverse extension (11b) of the deployed grid webs (11) in the expanded state II is larger than the transverse extension (11b) of the folded grid webs (11) in the compressed state I and the deployed grid webs (11) form a covering surface (12) in the expanded state II.

Description

Medical implant with a grid structure, medical device, method for its production and method for introducing the medical implant into a delivery system

description

The invention relates to a medical implant with a lattice structure, a medical device and a method for the production thereof as well as a method for introducing a medical implant into a delivery system.

A generic implant having the features of the preamble of claim 1 is known for example from US 6,843,802 Bl. The implant according to US Pat. No. 6,843,802 B1 is a self-expanding stent whose wall is formed from a lattice structure. The grid structure comprises closed grid cells whose geometry determines the flexibility of the stent. Good flexibility is important to be able to implant the stent in tortuous vessels with small radii of curvature.

In the stent according to US Pat. No. 6,843,802 B1, the geometry responsible for the flexibility in the implanted state is achieved by the elongated shape of the grid cells, which lead to an extension of the stent when deformed. The geometry of the grid cells of the stent according to US Pat. No. 6,843,802 B1 has the disadvantage that compressing during crimping and introduction into a delivery system, for example a catheter, can distort the lattice structure. This makes it difficult to accommodate the stent in the delivery system.

The distortion of the lattice structure is particularly noticeable in the region of the connection between two lattice webs, ie in the region of a tip of a lattice cell (Tip) noticeable. In this area, when the deformation of the stent is accompanied by a reduction in the opening angle of the grid cell, the outer area of the grid web expands particularly strongly. The stretching of the grid web at its outer edge is greater, the wider the grid web is. The overstretching is particularly pronounced when the angle of the grating is large. However, a great angle is for flexibility decisive. This increases the force required for the deformation of the lattice structure while reducing the opening angle of the individual lattice cells, and the crimping process is made more difficult. This applies not only in the connection region of two grid bars, but everywhere where the grid web undergoes a deformation.

An improved deformability of the grating structure for crimping can be achieved by reducing the width of the grating webs. However, thin grid webs have the disadvantage that they are difficult to produce with conventional processes, for example by laser cutting. In addition, the radial force of such lattice structures, which acts in the implanted state on the vessel wall, so that it may lead to insufficient expansion of the vessel, e.g. comes in a stenosis or in the expansion of a thrombus. The same applies to the stabilization of coils in an aneurysm. Thin grid bars also lead to a low coverage of the vessel wall. The narrower the grid bars are, the larger the unprotected, uncovered area of the vessel wall. Particles may detach from the stenosis or thrombus and coils may migrate into the vessel. Very thin grid bars can cut into the vessel wall. In addition, the forces acting on the vessel wall are concentrated on a small bridge surface, which promotes inflammatory reactions.

The invention is based on the object to improve a medical implant of the type mentioned so that the implant is easy to insert into a delivery system and has good mechanical properties in the implanted state. The invention is further based on the object to provide a method for producing such an implant and a method for introducing a medical implant into a delivery system.

According to the invention, this object with regard to the medical implant by the subject-matter of claim 1, with regard to the medical device by the subject-matter of claim 22, with regard to the method for producing such an implant by the subject-matter of claim 18 and with respect to the Method for introducing an implant into a delivery system by the subject-matter of claim 21.

The invention is based on the idea to provide a medical implant with a lattice structure comprising lattice webs and for insertion into a delivery system in a compressed state and implanted in a expanded state is convertible. The lattice webs each have a longitudinal extent and a transverse extent and are foldable along their longitudinal extent such that the lattice webs are folded in the compressed state and unfolded in the expanded state. The transverse extent of the unfolded grid bars in the expanded state is greater than the transverse extent of the folded grid bars in the compressed state. The unfolded grid bars in the expanded state form a covering surface.

The foldable grid bars are thus adapted such that they assume a folded or folded configuration in the feed system. When implanted, the foldable lattice webs assume an expanded, wide configuration that results in good coverage of the vessel wall. The foldable grid bars thus fold in the implanted state, i. in the at least partially expanded state in the vessel other than in the compressed state or during crimping for insertion into a delivery system such as a microcatheter.

When crimping, so when compressing the implant or the grid structure, the entire grid web folds along its longitudinal extent. This causes the crimp diameter or, in general, the dimension of the implant to be reduced in the compressed state despite a large number of grid webs with a cover area which is wide in the expanded state. In contrast to the prior art, this makes it possible to achieve small crimp diameters without reducing the number or the width of the grating webs in the implanted state.

Thus, the invention combines both the advantage of good crimpability and the small crimp dimensions with the advantage of the large coverage area in the implanted state by wide grid webs. This is made possible by the longitudinal foldability of the grid webs according to the invention.

The improved crimpability of the implant according to the invention is also favored by the nature of the expansion of the implant from the crimped to the expanded state, which occurs in other ways than in conventional stents. In the invention, the transition between the crimped and expanded state not only leads to a deformation of the web in the longitudinal direction, but also to a change or deformation of the grid web in cross section. This is an overstretching of the grid bars in the outer area during crimping and the associated Longitudinal deformation avoided or at least reduces the risk of such overstretching.

In addition, the invention allows a greater deformation of the grid structure or the grid webs, which is facilitated by a simultaneous deformation, or tapering of the cross-sectional profile of the webs. On the one hand, the web thus fulfills the requirements of a broad bridge in terms of coverage, force distribution and vessel protection. On the other hand, in crimping and deformation, the invention makes use of the advantages of a thin structure.

This can be adjusted and availed by the Faltbarkeit of the web and the corresponding restoring force an additional radial force. The webs tend to retire and unfold. The folded webs therefore tend to expand. The expansion leads to an opening of the entire structure. It is therefore possible to create new mechanisms for adjusting the desired force in the vessel, which are not based solely on a pure lattice deformation.

A further advantage of the invention is that the longitudinally foldable grid webs in the deployed state of the expanded implant have a flat or at least approximately flat cross-sectional profile and do not or only slightly protrude into the lumen or into the flow cross-section. This has a positive effect on the flow conditions. Thick webs, on the other hand, disturb the blood flow and swirls or dust areas can form behind the web. With conventional webs, the web thickness can only be reduced to a limited extent, otherwise the stability required for crimping will not be achieved and the webs distorted or twisted. Since the flexibility required for the crimping is achieved by the folding mechanism in the folding webs, the folding webs can be formed with a small thickness or wall thickness, ie with a low radial extension, which improves the flow properties, without the crimping stability is impaired. When crimping the cross-sectional profile in the radial direction and thus the stability is increased by the folding of the webs.

In comparison with conventional thin webs, the folding web can increase the radial force acting on the vessel wall in the implanted state by virtue of the fact that the folding mechanism generates an additional restoring force in the cross-sectional plane. In a preferred embodiment, the grid webs at least in sections each have at least two folding sections, which are at least partially connected in the longitudinal direction of the respective grid web and movable relative to each other for folding the grid web. The formation of the lattice webs with two folding sections offers a possibility of changing the width of the lattice webs by a relative movement of the folding sections relative to one another such that the lattice webs have a reduced transverse extent in the folded state and an increased transverse extent in the expanded state.

The grid bars can be profiled at least in sections. In particular, the grid webs may at least partially have a V-shaped cross-sectional profile. The profiling of the grid webs acts as a folding means, which initiates the folding process of the grid bars in a deformation of the grid structures, so that the transverse extent of the grid bars during crimping or during expansion is variable. The at least partially provided V-profile is particularly easy to manufacture and allows a simple and reliable functioning folding movement through the folding sections.

In a further embodiment, the grid webs have a folded edge arranged in the longitudinal direction of the respective grid web. The folding edge represents a possibility to set a predetermined folding structure of the grid bars.

The fold edge may connect the fold sections, the fold edge forming the bridge base about which the fold sections are pivotable. The folding edge and the folding sections have different opening angles at least in the expanded state. This ensures that the folding sections are movable in a large area relative to each other, so that in the implanted state, a large coverage area and in the compressed state, a small crimp dimension is achieved.

The distance of the folding sections of a grid web can be smaller in the compressed state than in the expanded state, wherein the folding sections are close to each other, so that a compact shape in the compressed state of the implant is achieved. The folding sections of a GitL bar can abut each other in the compressed state, whereby particularly small crimp dimensions are achieved.

In the implanted state, ie in the vessel, the folding sections can be arranged at least in sections in the circumferential direction of the grid structure and the Cover form. This ensures that the folding sections create a flat surface against the vessel wall and fulfill the support function in the implanted state.

It is not necessary but also not excluded that the folding sections in the expanded state of rest have the shape of the vessel. The lattice structure is oversized relative to the vessel diameter. Due to the residual radial force, the folding sections can bear against the vessel wall under deformation. It is advantageous in that the folding sections, or at least one outer region of the folding sections is flexible and can adapt to the profile of the vessel.

The folding sections can be connected in the implanted state by the folding edge, which interrupts the covering surface formed by the folding sections. The folding edge is thus formed so that it is present in the partially expanded state and forms a cavity to the vessel wall out, which can be used for example for the storage of drugs.

Alternatively, the folding sections can be stretched in the implanted state such that the folding sections form a continuous covering surface. Thus, a particularly large coverage of the vessel wall, a broad application of force and a small extension of the web is achieved in the vessel lumen.

The grid webs may be formed in their longitudinal extent at least partially rectilinear and / or curved, in particular multiple curved with the same and / or different radii. This makes it clear that the foldability of the grid bars is applicable to different configurations of the grid structure, so that the underlying principle of the foldability of the invention is flexible in different implant types or grid structures used.

The grid bars may include tips and / or connectors connecting two or more adjacent longitudinal bars. The foldability of the grid webs is not limited to the longitudinal webs, but also in the region of the connections between the Längsstεgcn, ie in the range of tips and / or connectors applicable, whereby the flexibility of the grid structure during crimping is further improved.

In a preferred disclosed embodiment of the invention, the grid bars are partially interrupted and form Faltausgleichsstellen. The Faltausgleichsstellen allow a relative movement of the folded portions of the grid bars, in particular in Longitudinal direction of the grid webs, so that the folding sections can dodge in the region of Faltausgleichsstellen. As a result, the longitudinal foldability of the grid webs is further improved.

The Querersteckung the grid bars may be different sizes in the expanded state sections. This also further improves the foldability of the grid bars, since the folding function can be limited, for example, to the areas of the grid bars or the grid structure in which a large covering area is particularly effective. Other areas of the lattice structure that are more difficult to fold on the other hand can be left out.

The transverse hemming of the grid bars in the area of the tips and / or the connectors can be smaller than in the area of the longitudinal bars. Thus, the foldability is improved, since due to the geometry of the tips and / connectors in these areas, the folding is more difficult than in the region of the longitudinal webs and due to the relatively smaller coverage area, the effect of covering the vessel wall is less than in the region of the longitudinal webs.

In another embodiment, the grid webs can be reinforced in the middle region between two adjacent covering surfaces, in particular in the region of the folded edges. As a result, the material safety is improved during the folding process, since the deformation caused by the folding of the grid bars occurs particularly strong in the central region between two adjacent covering surfaces, in particular in the region of the fold edges. The area at the lateral edge of the web, which serves as a folding section and cover (outside), may be thin-walled in such a way that an adaptation to the vessel wall is achieved.

To improve the endothelialization, the lattice webs may have a surface structuring, in particular in the region of the covering surface.

The invention is further based on the idea of specifying a method for producing an implant, in which a grid structure is produced with grid bars, which have a longitudinal extent and a transverse extent. The lattice structure is adapted in such a way that it can be converted into a compressed state for insertion into a delivery system and into an expanded state for implantation. During production, the grid webs are adapted such that they are foldable along their longitudinal extent such that the grid webs in the compressed state folded and unfolded in the expanded state. The transverse extent of the unfolded grid bars in the expanded state is greater than the transverse extent of the folded grid bars in the compressed state and the folded grid bars in the expanded state a covering surface.

In a preferred embodiment, the grid bars are deposited on a profiled substrate by a PVD method, in particular by sputtering. The use of PVD methods in connection with profiled substrates makes it possible in a simple manner to realize the foldability of the grid webs, since the profiled cross section of the substrate is imaged during the deposition of the material for the grid webs in the geometry of the grid webs and forms the folding profile. In addition, PVD processes make it possible to produce very thin webs, which is particularly advantageous in the area of folding sections.

Preferably, a continuous layer is deposited on the profiled substrate, etched into the formation of the grid bars, or the grid structure, in particular lithographically etched. In this way, the manufacturing process is further simplified because the PVD process is decoupled from the actual structuring of the layer.

The invention is further based on the idea of specifying a method for introducing an implant into a delivery system, wherein the implant has a lattice structure comprising lattice webs with a longitudinal extent and a transverse extent. In this case, the grid structure is converted from an expanded state into a compressed state and introduced into the feed system. When transferring the grid bars in the compressed state they are folded along their longitudinal extent.

According to a secondary aspect, the invention relates to a medical device, in particular for removing concretions from hollow organs of the body or for recanalizing hollow organs of the body, with a lattice structure comprising lattice webs. The medical device is for introduction into a delivery system in a compressed state I and for treatment in a hollow body organ in an expanded state II convertible. The lattice webs each have a longitudinal extent and a transverse extent, wherein the lattice webs are foldable along their longitudinal extent such that the lattice webs are folded in the compressed state I and unfolded in the expanded state II. The transverse extent the unfolded grid bars in the expanded state II is greater than the transverse extent of the folded grid bars in the compressed state I. The unfolded grid bars form a covering area in the expanded state II.

The embodiments explained in connection with the medical implant described at the outset also apply analogously to the medical device. Specifically, therefore, any combination of the medical device with the features of the subclaims 2 to 17 in the context of this application as claimed and disclosed.

In particular, devices for removing concrements, for example thrombus removal systems or thrombectomy devices, baskets, in particular suction baskets, for catching or catching thrombi or, in general, concrements, are disclosed as medical devices. Moreover, the medical device may include systems for recanalizing hollow organs of the body, such as recanalization systems, filters, for example for the treatment of carotid stenosis, and / or occlusion systems.

It is further pointed out that the manufacturing or working methods disclosed in connection with the implant described above are suitable analogously to the production or use of the medical device and are also disclosed and claimed in connection with the medical device.

The invention will be explained below with reference to embodiments with reference to the accompanying schematic drawings with further details. In these show:

Fig. Ia a cross section through a foldable grid web in the expanded

Status;

Fig. Ib is a cross section through the web of FIG. I a in the compressed

Status;

Fig. 2a shows a cross section through three foldable grid bars in the implanted

Status; Fig. 2b shows a cross section through the grid bars according to Fig. 2a in the compressed

Condition in a delivery system;

FIG. 3a shows a cross section through a substrate with a layer deposited thereon for producing the grid webs; FIG.

FIG. 3b shows the substrate according to FIG. 3a with a structured layer from which the

Grid bars are etched out;

3c, 3d further process examples for the production of the grid webs;

4a shows a cross section through a deposited layer substrate for the alternative production of the lattice webs;

FIG. 4b shows a cross-section through a substrate with a layer deposited thereon, which is reinforced in the region of the fold edge; FIG.

5a shows a cross section through a foldable grid web after another

Embodiment;

FIG. 5b shows a cross section through the grid web according to FIG. 5a in a vessel with a large diameter; FIG.

5c shows a cross section through the grid web according to FIG. 5a in a vessel with a relatively smaller diameter;

Fig. 6 is a perspective view of a section of a foldable

Grid web in the region of the connecting webs between two longitudinal webs;

Fig. 7 is a perspective view of a section of a foldable

Grid web in the region of the connecting webs between two longitudinal webs according to a further embodiment;

Fig. 8a, 8b, a comparison of the grid web of Figure 6 in the unfolded and in the folded state. Fig. 9a, 9b, a comparison of the grid web of Figure 7 in the unfolded and in the folded state.

10 is a perspective view of a section of a grid web with a curved geometry.

11 shows a perspective view of a detail of a grid web with folding sections arranged in sections;

12 is a perspective view of a section of a grid web with surface-structured folding sections;

13 shows a cross section through a foldable grid web after another

Embodiment;

Fig. 14a, 14b, a comparison of two grid structures with wide and narrow grid bars;

15 is a schematic representation of a stent according to an embodiment of the invention in the implanted state.

16a, 16b show an arrangement of four diamond-shaped grid cells for explaining the flexibility that can be generated by the grid structure;

17a, 17b show two different states of deformation of the arrangement according to FIGS. 12a, 12b and

18a, 18b an arrangement of four diamond-shaped grid cells with different diamond angles.

In Fig. Ia, the cross section through a grid web in the unfolded position and in Fig. Ib, the cross section through the grid web 11 in the folded position. The grid web 11 forms part of a lattice structure 10 of an implant for medical purposes. For example, the implant may be a stent used to treat stenosis, thrombosis, or aneurysms. The invention is preferably suitable for use in stents, without being limited thereto. The invention is also applicable to other medical implants having a grid structure comprising grid bars suitable, for example thrombosis scavengers, filters and the like. Implants are therefore also devices and instruments that are used temporarily within the body, such as thrombus.

The grid structure may include open or closed grid cells that allow flexibility of the grid structure to conform to the vessel shape. The lattice structure may include, for example, diamond-shaped cells, without being limited thereto. An example of such closed cells is given in FIGS. 16a, 16b.

In general, the invention is applicable to all grid structures in which the flexibility is based on a deformation mechanism of the grid cells. The deformation mechanism can be, for example, that the grid cells are elongated during deformation. An example of this is shown in FIGS. 16a, 16b. It can be seen that the individual grid cells of the grid structure deform, i. during the transition from the configuration according to FIG. 16 a into the configuration according to FIG. 16 b in the longitudinal direction of the implant, in particular of the stent. The flexibility that can be achieved in this way is used, as shown in FIG. 15, to insert the stent or, in general, the implant into vessels which have a high curvature, for example in the region of a bifurcation. It comes on the outside 22a of the stent 21 to a greater extension than on the inside 22b, or on the outside to an extension and on the inside to a shortening. This is achieved by the deformation mechanism as shown in Figs. 16a, 16b. The deformation also serves to adapt the grid structure to the vessel wall / or to the wall of the cavity. Beyond lengthening / shortening, the grid cell undergoes a reduction / increase in circumferential extent so that the entire perimeter of the grid can change and adapt to the wall.

For a good flexibility in the implanted state, the largest possible opening angle α is advantageous, since a comparatively large elongation is then achieved with a relatively small change in the angle of the opening angle of the grid cell. As a comparison of FIGS. 17a, 17b with FIGS. 18a, 18b shows, the elongation of the grid cell is achieved by 40% at a large opening angle α in the undeformed state by a smaller angle change (FIG. 17b) than in a grid structure with one smaller opening angle α in the undeformed state (Fig. 18b). In the latter case, a larger angle change is required to achieve the desired elongation of 40%. In addition, with smaller opening angles the possibility of Extension limited, because small deformations already lead to the maximum extension of the grid cell, in which the opening angle approaches a value of 0 °.

Therefore, a large opening angle α in the undeformed state is advantageous for the flexibility in the vessel. This applies if, as shown in FIGS. 17 a, 17 b, a limited angle change for the vessel flexibility is realized and the opening angle β in the implanted state is relatively large. When crimping into a delivery system, for example into a microcatheter, a very small opening angle β is set in the deformed state, which is required to bring the stent or generally the implant into a compressed state, wherein the crimp diameter is sufficiently small to be in the feeding system to be introduced. When crimping, the grid cell undergoes a relatively large change in angle when the opening angle α in the undeformed state is large. This can lead to a strong distortion of the lattice structure during crimping. To avoid this distortion, the material of the webs can be reduced, so that the web width is lowered. However, this leads to the problems mentioned in the introduction of thin webs.

The invention therefore takes a different approach and suggests, as exemplified by the embodiment of FIG. Ia, Ib, 2a, 2b, to design the grid bars 11 foldable. The strong deformation of the grid cells during crimping is compensated by the folding movement of the grid bars 11, whereby a distortion of the grid structure 10 during crimping is reduced. This means that the large opening angle of the grid cell, which is favorable for the good flexibility of the stent in the vessel, can be retained, without this impairing the flexibility of the stent for crimping. At the same time, the foldability of the lattice webs 11 ensures that they form a broad covering surface 12 for the vessel wall G in the implanted state.

The lattice webs 11 illustrated in FIGS. 1, 2 are elements of the lattice structure of a medical implant, which have a transverse extent Hb and a longitudinal extent I Ia. The transverse extent Ib is designated in the cross-sectional view according to FIG. 1 and the longitudinal extent Ha in FIG. 6 in each case with the double arrow. The longitudinal extent Ha describes the extent of the web in the longitudinal direction, ie the web length, which may be straight or curved. The transverse extension Hb describes the extension of the web in the transverse direction, so the web width. In the grid bars 11 are generally elongated elements which are distributed over the circumference of the implant and in places to form the Grid structure 10 are interconnected. In this case, the connection points between the grid bars 11, for example, tips 15 or connector associated with the grid bars 11, or referred to as such. An example of grid webs 11 in the region of a connection point is shown in FIG. 6. It can be seen that a tip 15 (tip) connects two longitudinal webs 16. The tip 15 is curved and the longitudinal webs 16 are formed in a straight line. The invention is not restricted to curved or straight lattice webs 11, that is to say encompasses all possible geometries of the webs, that is to say multi-lattice webs, as shown in FIG.

As shown in FIGS. 2 a, 2 b, the individual lattice webs 11 have an outer side 20 and an inner side 21. The outer side 20 is in the implanted state in direct contact with the vessel wall G and supports it. The inside 21 of the lattice web 11 is oriented radially inwards and limits the lumen of the implant or the stent.

The transverse Hb corresponds to the width of the grid webs on the one hand in the expanded state (Fig. Ia) and on the other hand in the compressed state (Fig. Ib) and is variable between the two states. For this purpose, the grid webs 11 as shown in FIG. 1, 2 along its longitudinal extent I Ia foldable. For this purpose, the grid webs 11 each have at least two folding sections 12a, 12b which extend in the longitudinal direction L of the respective grid web 11 (FIG. 6). The two folding portions 12a, 12b are formed so that they are movable relative to each other for folding. Moreover, the folding sections 12a, 12b are connected to one another in the longitudinal direction L of the respective grid web 11, in particular in sections, the connection point between the folding sections 12a, 12b acting as a type of joint about which the folding sections 12a, 12b are pivotable. The connection between the two folding sections 12a, 12b can be effected, for example, by a folding edge 14, which is arranged substantially centrally between the two folding sections 12a, 12b. As shown in Fig. 6, the folding edge 14 extends in the longitudinal direction L of the respective grid web 11. The folding edge 14 acts as a folding means and is in the expanded state II before such that the folding edge 14 during compression of the stent triggers the folding process of the individual grid bars. In the expanded state II, the folding edge 14 and the folding portions 12a, 12b have different opening angles αl, α2, wherein the opening angle α2 between the folding portions 12a, 12b is greater than the opening angle αl of the folding edge 14. This ensures that a bias voltage is generated , which acts in the implanted state III (Fig. 2a) on the vessel wall G and supports the radial force. The angle of the folding sections and the folding edge can be the same size. The folding sections and the legs of the folding edge are then each arranged in a plane. Also in this case, an additional radial force, caused by the elastic deformation of the folding sections is exerted on the vessel wall in the implanted state. In general, the folding sections can be connected, the folding edge forming a contact point, for example, in the form of a rounded profile between the two folding sections.

In the implanted state I according to FIG. 2a, the folding sections 12a, 12b are arranged in the circumferential direction U of the lattice structure 10 and form the covering surface 12. The folding edge 14 connecting the folding sections 12a, 12b interrupts the covering surface 12 formed by the folding sections 12a, 12b , This results in cavities 22 between the unfolded grid bars 11 and the vessel wall G, which can be used for example for the storage of drugs. It is also possible to stretch the folding sections 12a, 12b in the implanted state III in such a way that the folding sections 12a, 12b form a continuous covering surface 12, which is thus enlarged in comparison to the embodiment according to FIG. 2a.

In the compressed state I, as shown in Fig. Ib and 2b, the grid bars 11 are folded such that the transverse extent Hb of the folded grid bars 11 is smaller than the transverse extent Hb of the unfolded grid bars 11 in the expanded state II. Thus, the space requirement of Grid webs 11 reduced during crimping, so that, as shown in Fig. 2b, the system can be brought to a relatively small crimp diameter.

Overall, the grid webs 11 are at least partially profiled such that they are foldable. In the embodiment of FIGS. 1, 2, this profiling is achieved by a V-shaped cross-sectional profile, wherein the two outwardly directed legs of the V-shaped profile form the folding portions 12a, 12b. The base or bottom of the V-shaped profile between the two folding sections 12a, 12b forms the folding edge 14, about the longitudinal axis of which the folding sections 12a, 12b are pivotable.

As is apparent from FIGS. 5a, 5b, 5c, an exact separation between the web base body and the cover is not required. Rather, the exemplary embodiments shown are lattice webs formed in one piece or in one piece, in which the cover, that is to say the folding sections 12a, 12b, merges continuously into the base of the lattice web 11 or into the folded edge 14. It is also possible to replace the Ia, the Profϊlierung form with a single opening angle such that a simple V-shape of the lattice web 11 is formed in contrast to the double-V shape of FIG. Ia. Angles between the embodiment of FIG. Ia with different opening angles and the above embodiment with only one opening angle (simple V-shape) are possible, as shown with reference to FIG. 5a, which represents a lattice tegprofil with flatter outer areas or flatter folding sections 12a , 12b as the folding sections 12a, 12b shown in Fig. Ia.

Several areas with different angles are possible. It is also possible that a portion of the folding portion, e.g. the outer edge, in the expanded state has a shallow angle (α2 = 180 °). It is possible that the angle is even greater than 180 °, so that the folding sections adapt particularly gently to the curvature or the radius of the vessel wall.

In general, the angle between the folding means 12 and one of the folding sections 12a, 12b and / or along the folding section 12a, 12b can change from the inside to the outside. Viewed in the direction of the transverse extent, different areas with different angles can be provided.

As shown in Fig. 5a, a continuous change of the angle in the region of the folding means 12 and / or the folding portion 12a, 12b may be formed. The continuous change in angle can lead to a rounded shape of the web profile, in particular in the region of the folding means 12.

As can be seen in FIGS. 5b, 5c, the shape of the grid webs automatically adapts to the vessel diameter. The shape of the ridge in a large diameter vessel resulting in a relatively small radial force is shown in Fig. 5b. For small diameter vessels, the folding sections 12a, 12b are stretched and the folding edge 14 is flatter than for large diameter vessels, so that a greater radial force acts on the vessel wall (Figure 5c). As a result of the V-shaped profiling of the lattice webs 11 in their longitudinal direction L, not only is the foldability of the lattice webs achieved, but also their adaptation to different vessel diameters or vessel wall shapes.

The dimensions of the grid bars are in principle freely selectable. Thicknesses have proved particularly favorable _. 25, < _. 20, < _. 15, < _. 12, < _. 10, < _. 7, <5 μm proved. The values mentioned above can be found over the entire web, in particular the mentioned Transverse cover I Ib present or at least in the region of the folding sections 12a, 12b. In the area of the fold edge, the web thickness can alternatively < _. 100, < _. 80, <70, <60, <50, < _. 40, ≤ 30 microns. The web thickness can be variable over the transverse extent Hb and / or over the longitudinal extent I Ia. In one variant, the wall thickness in the region of the folding edge is greater than in the region of the folding sections, (FIG. 4 b), which is advantageous for the stability of the structure. The wall thickness can also be greater in the area of the folding sections than in the area of the folding edge. This leads to an improved foldability of the fold edge with smaller forces.

The remaining dimensions of the profiled, foldable lattice webs 11 are explained with reference to FIG. 13 and, in the context of this application, taken individually, as well as in combination with one another, are disclosed in the associations that are meaningful to the person skilled in the art. The length of the folding sections 12a, 12b is designated A in FIG. 13 and may be ≥ 20, ≥ 30, ≥ 40, ≥ 50, ≥ 60, ≥ 70 μm, in particular for grid diameters of less than or equal to 5 mm. In particular for grating diameters less than or equal to 12 mm, A> _ 50 μm> _. 100 μm:> 150 μm ≥ 200 μm ≥ 250 μm ≥ 300 μm. In the case of symmetrically foldable grid bars, the lengths A apply to both folding sections 12a, 12b.

The folding edge 14 forms, as shown in Fig. 13, a base of the web with two legs V-shaped arranged. This applies to all of the embodiments disclosed in the context of this application, that is also independent of the dimensions given below. It has proven to be expedient if the length S of a leg of the web base or of the folded edge is 14> 5,> 10,> 20,> 30 μm.

The width B of the grid web 11 in the idle state, ie in the fully expanded state II can>40,>50,>60,>80,>100,>125,>150,> _. 175,> 200, in particular for diameter <= 5 mm, or> _. 100 μm> _. 200 μm> _ 300 μm> _. 400 μm> _ 500 μm> _ 600 μm, in particular for diameters <= 12 mm. The ratio of the transverse extent Ha or the web width B according to FIG. 13 in the crimped state, ie in the compressed state I and in the expanded state II, ie at rest, can be <50%, <40%, <30%, <20%, <10 %.

Further exemplary embodiments, which differ in the geometry of the grid webs, are shown in FIGS. 6 and 10 to 12.

In the embodiment of FIG. 6 is the basic shape of the grid webs 11, in which two rectilinear longitudinal webs 16 with a tip 15th are connected. The tip or tip 15 is curved and has two folding sections 12a, 12b, which are likewise curved. The folding sections 12a, 12b of the individual web sections 15, 16 are connected to one another and form a continuous folding section, which is arranged laterally on both sides of the grid web 11 and forms its outer regions. Between the folding sections 12a, 12b of the section of the grid web 11 shown in FIG. 6 in the expanded state of rest, the folding edge is shown

14 arranged in the form of a web base. The folding edge 14 is continuous in the interconnected web portions, i. the longitudinal webs 16 and the connection point 15 is formed. In the case of the rectilinear longitudinal webs 16, the folding edge 14 is likewise rectilinear, as are the folding sections 12a, 12b, which extend in the longitudinal direction of the longitudinal webs 16. In the area of the connection tip 15 (tip), the folded edge 14 follows the curvature of the connection tip

15 between the two longitudinal webs 16, as well as the curved folding sections 12a, 12b. The tip 15 may also represent the connection to the longitudinally arranged cell. In this case, e.g. the folding sections 12a, 12b, or the outer folding section of the respective cell on the tip 15, represent a continuous folding section with the outer folding section of the longitudinally adjacent cell.

The embodiment of FIG. 7 has all the features of the embodiment of FIG. 6 and additionally includes Faltausgleichs make 17 in the region of the connection tip 15. The Faltausgleichs make 17 interrupt the folding sections 12a, 12b in the region of the junction 15 and each form a wedge-shaped recess the inner radius and / or outer radius of the connection tip 15th

In the embodiment of FIG. 10, the longitudinal webs 16 are repeatedly curved, in particular S-shaped curved. It is clear that the invention is not only applicable to straight grid bars, but the shape of the grid bars or their longitudinal extent is arbitrary selectable.

In the embodiment according to FIG. 11, the transverse extent Hb of the lattice webs 11 in the expanded state II is in sections of different sizes. Specifically, the transverse extent Hb of the grid webs 11 in the region of the tips 15 is smaller than in the region of the longitudinal webs 16.

In the embodiment according to FIG. 11, the cover formed by the unfolded folding sections 12a, 12b is limited to the straight web areas, in particular on the longitudinal webs 16. In the curved web areas, for example in the region of the connection point or connecting tip 15 no folding sections 12a, 12b are provided. It follows in general that the covering surface 12 formed in the unfolded or expanded state II is wider at the points where the deformation of the web during crimping is small, in particular in straight web sections. At the locations where the deformation of the grid web during crimping is particularly great, in particular in curved or curved web sections, the covering surface 12 is narrower or completely omitted in the expanded state II. As a result, the mechanical stress on the cover surface or the web cover is reduced. In general, the width or transverse extent Hb of the lattice webs, which determines the size of the covering surface 12, can be designed so variable along the longitudinal direction of the lattice web that optimum interaction between high radial force (broad web portions) and great flexibility and crimpability (thin web portions) is achieved. The covering surface 12 may be selectively provided with complex profiles in some places. As a further example, it is conceivable that the tip represents a connection between cells arranged in the longitudinal direction of the implant and in this region the width of the continuous folding section is reduced or the folding section is omitted in this area.

In the embodiment according to FIG. 12, the covering surface 12 has a surface structuring, for example in the form of openings or perforations. Other surface structures, including closed structures, suitable for improved endothelialization may be provided. The geometry of the surface structures, in particular the openings, is arbitrary. For example, structures or openings with dimensions between 5 and 100 μm, in particular between 10 and 60 μm, in particular between 20 and 30 μm, are suitable for good cell growth. In the region of the longitudinal webs 16 slots 19 may be provided. In the region of the curved connection tip 15 circular openings 19 may be provided. The perforations also ensure better circulation of lateral vessels.

Hereinafter, the operation of the foldable grid bars will be explained with reference to FIGS. 8, 9.

The profiled grid bars 11 behave differently in the vessel as well as during crimping than conventional stents. When crimping, the entire web folds along its longitudinal extension Ha, as shown in Figs. 8a, 8b and Fig. 9a, 9b. It happens to a relative movement between the folding portions 12a, 12b, which are moved towards each other during crimping. As a result, the width of the grid webs or their transverse extent Hb is reduced, as shown clearly in FIGS. 8b, 9b. In this way, the crimp diameter is reduced despite a high number of webs with wide covering surface 12.

The expansion of the stent from the crimped to the expanded state I, II is carried out in a different manner than in conventional stents. In the embodiments shown in FIGS. 8, 9, the deformation that occurs at the transition between the crimped and expanded configuration, not only by the deformation of the grid web in the longitudinal direction, but also by an effect on the transverse extent deformation of the grid web in Cross-section. In the V-shaped profiling of the lattice webs associated with the deformation elongation of the lattice webs 11 is transferred in a different manner than before to the cross section. Due to the shape of the V-profile, a high force can be generated despite low deformation. The deformation of the V-profile can also be done with a large diamond deformation or deformation of the grid cell without overstretching. The deformation of the V-profile takes place along the entire length of the web and is not concentrated on specific areas, as in a conventional design at the junction between two webs (connecting tip). As a result, webs of smaller wall thickness can be made without overstretching the deformation of the V-profile.

With regard to the method for producing the foldable grid webs, reference is made to FIGS. 3a, 3b, 3c, 3d and FIGS. 4a, 4b.

Therein, a method is shown, in which the profiled grid webs, in particular the V-shaped profiled grid webs are produced by a PVD method, in particular by sputtering. For this purpose, a substrate S, for example made of a sacrificial material, is provided, which images the negative profile of the implant to be produced, in particular of the stent. The production of the profile of the sacrificial material can be done for example by a galvanic, a lithographic, impression or LIGA method. In a following process step, a layer is deposited on the substrate S to form a thin-walled, V-shaped grid web. The layer thickness can be set as thin as desired, in particular by sputtering. By a subsequent process step, the individual grid bars are separated. A suitable method for structuring the grid bars is lithographic etching. In a further process example (FIGS. 3c, 3d), after sputtering, the coated surface of the substrate S is mechanically polished. The areas that connect the bars are thereby removed on one level.

In the case of the substrate S according to FIGS. 3a, 3b, the negative profile is formed in the form of substrate recesses. As can be seen in FIG. 4a, the negative profile of the substrate can also be formed by elevations. In this case, it is possible to deposit additional material at a limited location by suitably setting the parameters in the sputtering process. As shown in FIG. 4b, a web profile can thereby be produced in which the base has a thicker wall thickness in the region of the folding edge 14 than the covering surface 12 or the folding sections 12a, 12b. This design of the grid bars leads to an increased radial force and stabilization of the web.

The web can be made in a diameter and subsequently brought by deformation and possibly heat treatment to the target diameter. The stent may be made of nitinol, a chromium-cobalt alloy, a bioabsorbable material, e.g. Be magnesium. The grid structure can be produced in a preferred variant as a flat structure. A subsequent winding follows, in which the structure assumes a cylindrical or round profile. This is suitable e.g. especially for the manufacturing method according to FIGS. 4a, 4b, in which the cover, which later faces the vessel wall, is oriented inwards. The connection to a round profile after winding can be done by melting techniques, by laser, soldering, mechanical connection (crimping) also by additional elements, or gluing.

When producing an implant from a flat material, the material or the film may remain open. So it is possible to form by heat treatment, the film without connecting them. There are further possibilities in which the final shape is not a completely closed cylinder, but has a laterally open structure. It could, for example, be advantageous if the system covers, for example, an aneurysm on one side and leaves a vessel open on the other side. The film could be planar during manufacture and crimping in the delivery system and only conform to the shape of the vessel or lumen after implantation in the vessel.

Overall, the invention and the embodiments embodying the invention have the advantage that the grid bars are variable in their width, without the need for additional elements are required. The change in the web width is achieved by the foldability of the grid webs in the longitudinal direction. This allows the Grid webs in the deployed or expanded state of the implant form a relatively large coverage area, which supports the expansion of the vessel and allows better coverage and a finer force distribution. In the compressed state or in the crimped state, the grid webs are folded together, so that the web width is reduced and the grid webs require comparatively little space. In this way, very small crimp diameters are possible. The invention thus combines the good mechanical properties of the implant with the good crimpability in small delivery systems.

All features of

mentioned embodiments are also in connection with the medical device, in particular in connection with temporarily insertable into the body devices, such as devices for removing concrements, especially thrombus removal systems or thrombectomy devices, baskets, especially suction baskets, for gripping or catching thrombi or generally concretions, as well as systems and devices for recanalizing hollow organs of the body, in particular recanalization systems, filters, for example for the treatment of carotid stenosis, and / or occlusion systems disclosed and claimed.

LIST OF REFERENCE NUMBERS

10 lattice structure

11 grid bars

I I a longitudinal extension

I Ib transverse extension

12 covering area

12a, 12b folding sections

13 Cross section profile

14 folding edge

15 tips or connection tips

16 longitudinal bars

17 folding compensation points

18 middle area

19 Surface structuring

20 outside

21 inside 22 cavities

G vessel wall

L longitudinal direction

U circumferential direction

S substrate

Claims

claims

1. A medical implant with a lattice structure (10), the lattice webs (11) and can be converted for insertion into a delivery system in a compressed state I and for implanting in an expanded state II, wherein the lattice webs (11) each have a longitudinal extent (Ha ) and a transverse extension (Hb), since they are characterized by the fact that the lattice webs (11) are foldable along their longitudinal extent (IIa) such that the lattice webs (11) fold in the compressed state I and unfold in the expanded state II are, wherein the transverse extent (Hb) of the unfolded grid bars (11) in the expanded state II is greater than the transverse extent (Hb) of the folded grid bars (H) in the compressed state I and the unfolded grid bars (11) in the expanded state II, a covering surface ( 12) form.

2. Implant according to claim 1, da chgekennz egg chn characterized in that the lattice webs (H) at least partially each have at least two folding sections (12a, 12b) connected in the longitudinal direction L of the respective grid web (H) at least in sections and for folding the Grid web (H) are movable relative to each other.

3. Implant according to claim 1 or 2, characterized in that the grid webs (11) are profiled at least in sections, in particular at least in sections, have a V-shaped cross-sectional profile (13).

4. The implant according to claim 1, wherein the lattice webs (11) have a folding edge (14) arranged in the longitudinal direction L of the respective lattice web (11).

5. Implant according to claim 4, characterized in that a chn egg chnet that the folding edge (14), the folding portions (12a, 12b) (12a, 12b) connects.

6. Implant according to claim 4 or 5, characterized marked eichne t, that the folding edge (14) and the folding portions (12a, 12b) at least in the expanded state II different opening angle αl, α2.

7. Implant according to at least one of claims 2 to 6, characterized in that the distance of the folding sections (12a, 12b) of a grid web (11) in the compressed state I is smaller than in the expanded state II or the folding sections (12a, 12b ) of a grid web (11) in the compressed state I abut each other.

8. Implant according to at least one of claims 2 to 7, characterized in that the folding sections (12a, 12b) are arranged in the implanted state III at least in sections in the circumferential direction U of the grid structure (10) and form the covering surface (12).

9. Implant according to claim 8, characterized in that the folding sections (12a, 12b) in the implanted state III are connected by the folding edge (14), which interrupts the covering surface (12) formed by the folding sections (12a, 12b).

10. Implant according to claim 8, characterized in that the folding sections (12a, 12b) are stretched in the implanted state III such that the folding sections (12a, 12b) form a continuous cover surface (12).

11. The implant according to at least one of claims 1 to 10, characterized eichnet that the grid webs (11) in their longitudinal extent (IIa) at least partially rectilinear and / or curved, in particular multiple curved with the same and / or different radii are formed.

12. An implant according to at least one of claims 1 to 11, characterized in that the lattice webs (11) comprise tips (15) and / or connectors, each connecting two or more adjacent longitudinal webs (16).

13. Implant according to at least one of claims 1 to 12, as characterized by gekennz eichne t, that the grid webs (11) are partially interrupted and form Faltausgleichsstellen (17).

14. Implant according to at least one of claims 1 to 13, characterized marked eichne t, that the transverse extent (Hb) of the grid webs (11) in the expanded state II sections is different in size.

15. Implant according to claim 14, characterized in that the transverse extension (Hb) of the lattice webs (11) in the region of the tips (15) and / or connectors is smaller than in the region of the longitudinal webs (16).

16. Implant according to at least one of claims 1 to 15, characterized in that the lattice webs (11) are reinforced in the middle region (18) between two adjacent covering surfaces (12), in particular in the region of the folding edges (14).

17. Implant according to claim 1, characterized in that the lattice webs (11) have a surface structuring (19), in particular in the region of the covering surface (12).

18. A method for producing an implant, in which a lattice structure (10) with lattice webs (H), which have a longitudinal extent (IIa) and a transverse extent (Hb), is manufactured, wherein the grid structure is adapted such that these for introduction into a delivery system can be converted into a compressed state I and into an expanded state II for implantation, characterized in that the lattice webs (11) are adapted during manufacture in such a way that they extend along their longitudinal extent (Ha) are foldable such that the grid webs (11) are folded in the compressed state I and unfolded in the expanded state II, wherein the transverse extent (Hb) of the unfolded grid webs (11) in the expanded state II is greater than the transverse extent ( Hb) of the folded lattice webs in the compressed state I and the unfolded lattice webs (11) in the expanded state II form a covering surface (12).

19. Method according to claim 18, characterized in that the lattice webs (11) are deposited by a PVD method, in particular by sputtering on a profiled substrate.

20. Method according to claim 19, characterized in that a continuous layer is deposited on the profiled substrate into which the grid structure (10) is etched, in particular lithographically etched, to form the grid bars (11).

21. A method for introducing an implant with a lattice structure (10), the lattice webs (11) having a longitudinal extent (IIa) and a transverse extent (Hb), in a feed system in which the lattice structure (10) from an expanded state II is converted into a compressed state I and introduced into the feed system, characterized in that the grid webs (H) are folded along their longitudinal extent (Ha) when transferred to the compressed state I.

22. A medical device, in particular for removing concretions from hollow organs of the body or for recanalizing hollow organs of the body, with a lattice structure (10) comprising lattice webs (11) and for insertion into a delivery system in a compressed state I and for treatment in a hollow body organ in a expanded state II can be transferred, wherein the grid webs (11) each have a longitudinal extent (Ha) and a transverse extent (Hb), wherein the grid webs (H) along its longitudinal extent (Ha) are foldable such that the grid webs (11) in the compressed State I folded and unfolded in the expanded state II, wherein the transverse extent (Hb) of the unfolded grid webs (H) in the expanded state II is greater than that Transverse extension (Hb) of the folded grid webs (11) in the compressed state I and the unfolded grid webs (11) in the expanded state II form a covering surface (12).