EP2593151A1 - Implant médical et procédé de fabrication d'un tel implant - Google Patents

Implant médical et procédé de fabrication d'un tel implant

Info

Publication number
EP2593151A1
EP2593151A1 EP11741104.1A EP11741104A EP2593151A1 EP 2593151 A1 EP2593151 A1 EP 2593151A1 EP 11741104 A EP11741104 A EP 11741104A EP 2593151 A1 EP2593151 A1 EP 2593151A1
Authority
EP
European Patent Office
Prior art keywords
grain size
implant
different
layers
implant according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP11741104.1A
Other languages
German (de)
English (en)
Inventor
Giorgio Cattaneo
Eckhard Quandt
Rodrigo Lima Dr. DE MIRANDA
Christiane Dr. Zamponi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Acandis GmbH and Co KG
Original Assignee
Acandis GmbH and Co KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Acandis GmbH and Co KG filed Critical Acandis GmbH and Co KG
Publication of EP2593151A1 publication Critical patent/EP2593151A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
    • A61L31/02—Inorganic materials
    • A61L31/022—Metals or alloys
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/82—Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
    • A61L31/14—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
    • A61L31/148—Materials at least partially resorbable by the body
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
    • C23C14/14—Metallic material, boron or silicon
    • C23C14/16—Metallic material, boron or silicon on metallic substrates or on substrates of boron or silicon
    • C23C14/165—Metallic material, boron or silicon on metallic substrates or on substrates of boron or silicon by cathodic sputtering
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2210/00—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
    • A61F2210/0004—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof bioabsorbable
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2240/00—Manufacturing or designing of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
    • A61F2240/001—Designing or manufacturing processes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2250/00—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
    • A61F2250/0014—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof having different values of a given property or geometrical feature, e.g. mechanical property or material property, at different locations within the same prosthesis
    • A61F2250/003—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof having different values of a given property or geometrical feature, e.g. mechanical property or material property, at different locations within the same prosthesis differing in adsorbability or resorbability, i.e. in adsorption or resorption time

Definitions

  • the invention relates to a medical implant and a method for producing such an implant.
  • the preamble of claim 1 is described for example in WO 2007/027251 A2.
  • adhesion promoter layers must be used for this purpose. After degradation of the polymer occurs an uncontrolled absorption of the body or carrier, which can lead to the separation and detachment of stent areas. In addition, the polymer layers are sensitive to mechanical Damage when crimping or discharging from a catheter. To the
  • Damaged areas cause premature absorption of the body.
  • Certain polymer coatings can cause problems with the sterilization of the implant.
  • Endothelium impair. Therefore, it may in the decomposition of the implants to side effects such. As come to hyperacidity, which hinder the healing and can lead to inflammation.
  • the invention has for its object to provide a medical implant that allows improved control and slowing down the rate of absorption. Moreover, the formation of hydrogen in the degradation of the implant should be avoided or at least reduced.
  • the invention is also based on the object of specifying a method for producing such an implant.
  • the object is determined by the subject matter of the implant
  • the invention is based on the idea of addressing a medical implant for intravascular use comprising a body of lattice structure which is compressible and expansible and comprises a biodegradable magnesium alloy material.
  • the magnesium alloy is supersaturated with at least one alloying component, wherein the magnesium alloy is obtainable by sputtering one or more targets whose material contains the components of the magnesium alloy and depositing the gaseous phase-transferred target material onto a substrate to form a material structure such that the supersaturated alloying component in solid solution is present.
  • the invention has the advantage that the properties of the implant, in particular the dissolution behavior, can be influenced in a targeted manner by the supersaturation of the magnesium alloy with at least one alloy component.
  • the supersaturation with the alloying component zinc can prevent or at least reduce the formation of hydrogen.
  • achieving alloy by melt metallurgy leads to the problem that, as the melt cools, the alloying components concentrate at the grain boundaries, especially at the boundaries of the magnesium grains. As a result, the effect, in particular a homogeneous effect of the supersaturated alloy component is impaired.
  • the degree of saturation of zinc is, for example, about 2.4 at.% In the case of a magnesium alloy produced by fusion metallurgy.
  • the concentration of the supersaturated alloying component at the grain boundaries leads to a reduction of the mechanical stability by the occurrence of breakages. This accelerates the corrosion of the implant by creating preferential corrosion paths.
  • the alloying component zinc is distributed inhomogeneously by the fusion metallurgical production, so that the formation of hydrogen during the degradation of the implant is only insufficiently prevented.
  • the invention has the advantage that on the one hand miniaturized
  • Implants such as stents, from a supersaturated magnesium alloy, in particular with zinc-supersaturated magnesium alloy can be made at all.
  • the invention has the advantage that the at least one alloying component, in particular the alloying component zinc in the supersaturated state, is homogeneously incorporated in the magnesium matrix, ie. H. essentially completely in solid solution.
  • the invention provides that the magnesium alloy by sputtering one or more targets whose material the
  • Containing components of the magnesium alloy and deposition of the gas-phase-transferred target material on a substrate for forming the lattice structure is available, such that the alloy component, in particular zinc is in solid solution.
  • the material may be in the amorphous or crystalline state.
  • the supersaturation with an alloying component, in particular with zinc, can influence the structure formation and thus the corrosion behavior.
  • the supersaturated state of the alloying component can lead to the formation of an amorphous structure rather than a crystalline structure. With an amorphous structure, corrosion is slowed down because corrosion does not proceed over preferred corrosion trenches. Forming hydrogen is better degraded by the body, because the process is slower.
  • Sputter-deposited magnesium tends to form crystals.
  • the sputtered magnesium can form an amorphous structure.
  • An amorphous structure is advantageous for corrosion and has favorable mechanical properties, for example a good one
  • the invention therefore comprises amorphous structures.
  • crystalline lattice structures can be set in supersaturation with alloying elements, for example by a heat treatment. Also in this case, the dissolved alloying elements in the supersaturated state or the at least one alloying element in the supersaturated state to a
  • the invention therefore comprises crystalline structures.
  • the crystalline lattice structure can form directly by sputtering.
  • an amorphous lattice structure can be set, which can be converted by heat treatment into a crystalline lattice structure.
  • the mentioned advantages of supersaturation with additives or alloy components exist.
  • the at least one alloying component present in the supersaturated state may comprise zinc and / or calcium and / or elements from the group of rare earths.
  • the at least one alloy component may comprise yttrium or neodymium or gadolinium.
  • the alloying component zinc can be present at a level of about 2.4 at.% To 35 at.%.
  • the magnesium alloy comprises zinc as a compulsory component with a content of 28 at% to 35 at%.
  • Component calcium at a content of 1 at-% to 5 at-%, wherein the rest are magnesium and unavoidable impurities.
  • the content of the alloy components may change along the lattice structure such that different regions of the body have different dissolution rates, thereby affecting the dissolution behavior of the implant.
  • the rate of corrosion along the length of the stent or the implant length may change continuously, in particular gradually, or gradually, due to the changing composition.
  • the implant or stent breaks down faster in one direction than in the other.
  • the implant, in particular the stent can degrade so that the ends corrode faster than the center of the implant.
  • the central implant area which decouples the aneurysm from the blood flow, advantageously remains longer in time.
  • the edges or axial ends of the implant, which are already covered by endothelial tissue faster, are degraded faster. It is also possible that the
  • Corrosion rate changes in the circumferential direction.
  • the implant can be positioned so that a lateral area, which is positioned in the region of an aneurysm, stops longer than the radially opposite
  • the advantage of the method according to the invention is that the alloy composition and the material properties, in particular the microstructural properties of the implant, can be very finely adjusted by the PVD method, that is, by a method based on the physical gas deposition. Furthermore, the grain size of the crystalline material can be controlled well, so that a targeted grain-fine, in particular a targeted grain refining, can be adjusted. With the method according to the invention, a high grain refining, i.
  • the body has at least two components
  • the crystalline material of the first region has a different grain size, as the crystalline material of the second region.
  • Implant the properties of the implant can be controlled depending on the particular structure.
  • the setting of different grain sizes in different areas of the implant is particularly well by the use of PVD method, in particular by sputtering, feasible.
  • the at least one region of the implant forms a spatially extended material region which has substantially homogeneous physical properties, for example the dissolution properties of the material.
  • the at least one other region of the implant forms another spatially extended material region which has substantially different homogeneous physical properties, in particular a different dissolution rate of the material.
  • the different material areas are separated from each other in the sense that in one area a grain size and in the other area is a different grain size. They represent discrete regions, in contrast to a microstructure, in which different particle sizes, in particular different mean particle sizes, for example of different alloy components, are mixed in one and the same area.
  • a material area forms a coherent massive fabric area.
  • the fabric region forms, in particular macroscopically, the structure or a part of the structure of the implant, in particular of the implant body.
  • the material areas in particular form part of the implant wall. Specifically form the
  • the size, extent and shape of the respective region is not limited per se, but adapted such that a property set in the region, for example the dissolution rate, has an influence on the behavior of the implant.
  • the size of the respective area required for this purpose depends on the wall thickness and / or the dimension of the implant or a structural element of the implant formed by the area and can thus be determined by the person skilled in the art, depending on the application and need.
  • the material in particular by the grain size, which varies in different areas different.
  • the material can be single-phase or multi-phase.
  • different areas of the body of the implant can form layers which are arranged on top of each other.
  • the layers have different particle sizes; in concrete terms, the particle size present in one layer differs from the particle size present in another layer, so that different properties, for example different absorption rates, can be set in layers.
  • several layers are subsequently applied one above the other until the desired layer thickness has been reached.
  • the individual material layers of a layer have the same grain size, so that the overall result is a greater layer thickness with a uniform (average) grain size. In this case, a plurality of such multi-layer sputtered layers can be combined with each other, wherein a different grain size is set per layer.
  • the layers may comprise at least one outer layer and one inner layer, wherein the grain size of the material of the outer layer is smaller than the grain size of the material of the inner layer.
  • the outer layer of the implant comes in the body with the body fluid, in particular a vessel wall in
  • the inner layer in this case forms a middle layer or a core layer, so that the overall result is a sandwich-like structure.
  • the inner layer or middle layer is protected against bodily fluid on both sides by the outer layer, which is arranged radially inward and radially outward. It is also possible to reverse the above-described dissolution behavior in that the grain size of the material of the at least one outer layer is greater than the grain size of the material of the inner layer.
  • This embodiment is suitable for influencing structural elements or web elements that initially exert a relatively high initial force on the vessel wall during implantation in such a way that the high initial force drops relatively quickly due to the rapidly degradable outer layer. After removal of the outer layer, a relatively thin, less rapidly absorbable layer remains, which, in contrast to the expansion function of the original stake element, essentially only assumes a supporting function.
  • the body comprises more than two layers arranged on top of each other, wherein the grain size of the material of the respective layer increases with increasing distance from the outer layer. This ensures that the absorption rate gradually increases with increasing dissolution of the implant. Again, it is possible to reverse this behavior by the grain size of the material of the respective layer decreases with increasing distance from the outer layer.
  • the layers with the different grain sizes so that the layers on both sides of the middle or core layer have grain sizes which decrease or increase towards the core layer.
  • the properties change layer by layer with increasing resolution.
  • the changes in the absorption rate with increasing dissolution of the implant can be used as required and as a treatment objective and combined with one another by providing different regions of the implant with different absorption properties.
  • the body has a plurality of structural elements, in particular lattice webs.
  • the structural members may generally include stent members, such as the aforementioned grid bars, closed cells, connectors, end sheets, and the like, other functional elements.
  • at least one of the structural members may generally include stent members, such as the aforementioned grid bars, closed cells, connectors, end sheets, and the like, other functional elements.
  • Structural element at least two different areas with different grain sizes and / or each one structural element consists of one area with a grain size and each a further structural element of another area with a different grain size.
  • whole structural elements differ in terms of their grain size, each structural element in itself having a substantially uniform grain size.
  • there is an entire structural element for example a grid web from the first region with a first grain size.
  • Another structural element for example a further grid web, forms a second area with a different grain size.
  • the grain size of the first region or first structural element can be greater or smaller than the grain size of the second region or second structural element, depending on at which point of the implant a desired dissolution rate is to be set.
  • a single structural element it is also possible for a single structural element to have different regions with different particle sizes, so that different dissolution rates can be set within the same structural element. This makes it possible, for example, to cut through a structural element or a lattice web at a desired location in order to prevent the flow of force. In the region of the separation point, the grid web or the structural element has an area with a relatively large grain size, so that this area is degraded relatively quickly, whereas the remaining area of the structure element remains with a finer grain size.
  • first structural elements can be provided, which in the implanted state apply a greater supporting force than second structural elements, the material of the first structural elements having a smaller particle size than the material of the second structural elements. This means that the first structural elements
  • the second structural elements have a retention function such that the second structural elements expand the diameter of the stent or another Counteract implant.
  • the second structural elements therefore form bridges which limit an expansion movement of the implant, in particular of the stent.
  • the second structural elements or bridges are resolved with larger grain sizes quickly.
  • an increase in diameter occurs, so that the first structural elements can unfold their supporting force acting on the vessel wall.
  • an implant can be realized that increases the radial force on the vessel wall with increasing duration of treatment. This can be done, for example, in so-called remodeling, i. be advantageous in the reconstruction of the vessel inner wall.
  • the support force can be reduced by the first support elements are also degraded, but at a slower rate of dissolution than the second support elements.
  • the structural elements have layers with different grain sizes. This ensures that the dissolution behavior in the thickness direction, ie normal to the implant surface, changes.
  • the crystalline material may include corrosion trenches such that dissolution of the material in the implanted state occurs along the corrosion trenches, thereby enabling geometrically predetermined resolution of at least some areas of the implant or the complete implant.
  • the various regions may be web-shaped, with the grain size of at least one web-shaped region and the width of the web-shaped region in the ratio 1: 15 to 1: 100. This ensures that the
  • Grain size in each case is much smaller than the web width or generally the width of the areas or the structural elements.
  • the biodegradable crystalline material or as the biodegradable crystalline materials magnesium alloys and / or iron alloys may be used.
  • the transition between the regions is discontinuous, wherein the grain size changes abruptly.
  • the transition between the regions may be continuous, with the grain size continuously changing in a transition region between the two regions.
  • the continuous change of the grain size in the transition region between the two regions having the different grain sizes has the advantage that the physical properties, in particular the dissolution speed, between the regions gradually change.
  • the continuous transition also has a positive influence on the cohesion of the material. There is a particularly good adhesion between the layers when the material properties change continuously.
  • the outer layer envelops the inner layer.
  • the outer layer thus completely surrounds the inner layer or the inner region, that is to say also at the lateral edges of the inner layer or the inner layer
  • the inner layer enveloped by the outer layer forms a core that is shielded from bodily fluid by the outer layer in use.
  • This has the advantage that the dissolution behavior of the body or of the implant at the beginning of the dissolution of the structure of the outer layer and, after dissolution of the outer layer, only then from the structure of the inner layer or respectively of the corresponding grain size is determined.
  • the corrosion between the laminates in which a laminate side is freely accessible the corrosion between the
  • FIG. 1 shows the structure of a structural element, in particular a grid web according to the prior art.
  • Fig. La the microstructure of FIG. 1, in which an intercrystalline corrosion
  • Fig. 2 shows the structure of a structural element according to an inventive
  • Fig. 3 shows the structure of a structural element according to another
  • FIG. 3a the structure of FIG. 3, in which an intergranular corrosion
  • FIG. 4 shows the microstructure of a structural element comprising two layers according to an exemplary embodiment of the invention.
  • FIG. 5 is a view of a body of an implant after a
  • Embodiment according to the invention with different areas having different grain sizes.
  • the body 10 or the lattice structure forming the body 10 is made of a zinc-supersaturated one
  • Magnesium alloy produced The supersaturation with other alloy components is possible.
  • the alloying component zinc is present in solid solution, ie the alloying component zinc does not form a separate phase in the lattice structure of the magnesium.
  • the homogeneous distribution of the alloying component zinc in the magnesium matrix achieved in this way ensures that the formation of hydrogen during the degradation of the magnesium alloy is uniformly or substantially completely prevented.
  • the formation of a magnesium / zinc mixed crystal is achieved by the production of the magnesium alloy or the lattice structure achieved by a PVD process in which one or more targets are atomized and the gaseous phase-transferred target material is deposited on a substrate to form the lattice structure. It is possible to coat an existing support structure with the supersaturated magnesium alloy.
  • self-supporting lattice structures or a self-supporting lattice structure can be produced by the PVD method.
  • the self-supporting structure is dispensed with a support structure and applied the material of this structure completely by the PVD process.
  • layers are deposited on a substrate until the desired wall thickness of the grid structure is reached.
  • a method for producing self-supporting lattice structures for medical implants is disclosed, for example, in DE 10 2006 029 831 and in DE 10 2001 018 541, both of which are to the Applicant. The content of both registrations will be through
  • the implant properties may gradually change across the thickness of the structure.
  • the change can be continuous so that there are no discrete layer transitions. Rather, the composition of the layers changes gradually, resulting in an overall continuous change in the composition of the magnesium alloy over the lattice structure.
  • the gradual change in the composition is achieved by a continuous change of the sputtering parameters or, in general, the production parameters in the PVD process.
  • This is not possible with conventional melting processes.
  • the distance of the target of the structure to be produced can be continuously changed, in particular reduced or increased. This results in different compositions, even in targets with homogeneous target materials.
  • a plurality of targets, in particular movable targets can be used in the context of the method. It is possible to use the targets simultaneously or alternately. Due to the continuous changes of Sputtering parameters for both targets, the change in the target composition of the alloy can be achieved.
  • the zinc content of the magnesium alloy of the lattice structure can be continuously increased, so that the corrosion rate is gradually reduced in different material areas of the lattice structure.
  • the different material areas may extend in the direction of the wall thickness, i. H. in the radial direction and / or along the lattice structure, d. H. change in the axial direction.
  • Inner wall of the implant and / or the outer wall of the implant are present. It is also possible to have the innermost and / or outermost layer of the lattice structure, i. H. form the composition in the edge region of the wall as a zinc oxide layer, in particular partially or completely form. Such a zinc oxide layer significantly slows down the corrosion of the material.
  • the formation of the zinc oxide layer can be achieved for example by reaction sputtering with oxygen content.
  • the core of the webs thus consists of a material with lower zinc concentration and is surrounded by material with a higher zinc content, in particular completely enclosed.
  • the continuously varying compositions of the layered layers have the significant advantage over a discrete layer structure with a sudden change in the properties of the individual layers or the composition of the individual layers, that the layers adhere better to each other, when the properties of the layers continuously change, as provided in inventive method or its embodiments.
  • Magnesium alloys alloyed with aluminum, titanium or other alloying elements are possible. These alloys are disclosed in connection with a supersaturated zinc content.
  • the above-mentioned features are disclosed and claimed both in connection with the implant and in connection with the production method. Moreover, the above-mentioned features in. Connection with the embodiments described in more detail below, in particular with regard to the setting of different areas of the lattice structure with different grain sizes disclosed and claimed.
  • the method according to the invention or its embodiments offer an excellent alternative to the conventional techniques used for the production of biologically degradable implants, in particular stents.
  • the PVD methods according to the invention in particular the sputtering processes, allow the setting of very small particle sizes, whereby the absorption rate of the implant material is greatly reduced in comparison to known implant materials.
  • PVD methods or sputtering processes have the advantage that the material properties, in particular the grain size, can be varied in certain areas, so that the absorption rate in different implant areas
  • the resolution of the implant is well controlled.
  • the sputtering has the advantage that the distribution of the elements in the alloy can be finely adjusted. Precipitations are avoided in contrast to conventional melting technologies, since the magnesium or iron can be supersaturated with alloying elements, thus increasing the dissolution rates in further
  • Borders can be varied.
  • the second phases can be better distributed. Furthermore, it is possible to reduce the dissolution rate by the fine, targeted adjustment of the alloys.
  • Sputtering also has the advantage that larger amounts of additional elements or a plurality of different additional elements that slow down the resolution, for example, can be introduced into the material, as is possible with conventional melting technologies. In the case of the latter, precipitation processes often occur, which render the mechanical properties of the implant unfavorable
  • any thin layers can be formed, which have different properties, especially with regard to the resolution of the implant.
  • the production of bioabsorbable implants Sputtering also has the advantage that the material properties along the implant, ie in the axial, radial and circumferential direction can be changed.
  • the direction of dissolution from the inner diameter to the outer diameter from
  • Stegrand to the bridge core be influenced by the stent ends to the stent center or in each case vice versa.
  • intermediate layers can be introduced, which reduce the dissolution rate, so that the faster
  • dissolving core of the implant or the individual structural elements only begins to dissolve when the intermediate layer is completely degraded.
  • corrosion trenches can be introduced, so that the resolution is initially directed along predefined paths.
  • the sputtering process can be combined, for example, with a lithography process. It is also possible to integrate path-like areas in the implant wall with a relatively large grain size, so that these areas corrode before the surrounding material. It is also possible to subsequently introduce corrosion trenches by etching.
  • the resolution can be controlled by the length of these paths.
  • web geometries can be defined with which the resolution can be controlled.
  • the upper limit for the corrosion-slowing grain size can be set to 175 pm, 150 pm, 125 pm, 100 pm, 75 pm, 50 pm, 25 pm, 20 pm, 15 pm, 10 pm, 8 pm, 6 pm, 4 pm.
  • the lower limit depends on the process parameter and may be 2 pm or less, in particular at least 1.8 pm, in particular
  • one area may have a grain size of 2 pm and another area may have a grain size of 20 pm.
  • Other different regions with different grain sizes may be provided.
  • a third region may have a grain size of 100 pm. It is also possible that further additional regions have the grain sizes of 200 ⁇ m known and customary in the prior art, so that these regions have a particularly fast resolving power.
  • the method according to the invention is suitable for producing different medical implants which are at least partially biodegradable. Particularly preferred is the process for producing biodegradable stents. It is also possible to use the method of manufacturing filters which are removed after a predetermined time by dissolution. Such filters are used, for example, in the cerebral area to prevent blood particles from clogging cerebral vessels. A common reason for the formation of clots and subsequent particle detachment is the expansion of a stenosis in the carotid area or the implantation of a heart valve. In the first phase after appropriate
  • a filter along with anti-clotting therapy is beneficial.
  • anti-coagulant agents may be discontinued if the risk of particle detachment decreases.
  • Such a filter can be particularly advantageous with the aid of the invention
  • Process or an embodiment of the method can be produced.
  • occlusion devices or devices that minimize blood flow or lead to other collateral vessels are used. After completion of the treatment, this device or the occlusion device is to be absorbed in order not to impair the physiological flow in the long term.
  • Such occlusion devices or devices can advantageously be produced with an embodiment of the method according to the invention.
  • the method according to the invention is not restricted to the production on the above-mentioned medical implants, but can be further
  • At least one biodegradable crystalline material is coated on a base body, in particular by sputtering.
  • Suitable crystalline materials are metals and metal alloys which are biodegradable, for example magnesium or iron or magnesium alloys and / or iron alloys. It is also possible with the method to integrate different materials, in particular two, three or more than three materials, in regions in the implant. Thus, the method is also outstandingly suitable for connecting different materials in a materially bonded manner, so that an implant can be produced which is constructed in regions from different materials, in particular different biodegradable materials.
  • the grain size of the applied crystalline material is adjusted so that it is less than 200 pm.
  • the base body, on which the crystalline material is sputtered, may be made at least partially of a biodegradable material.
  • the basic body can be replaced by others
  • the base body can have a different microstructure, in particular other particle sizes, than the bioabsorbable crystalline material applied by sputtering to the base body.
  • the crystalline material forms a self-supporting body of the implant, which is produced by sputtering.
  • the support structure of the body is made by sputtering.
  • implants which are at least partially made of a biodegradable, crystalline material, in particular of a metallic material.
  • the grain boundaries 17 of the grains 18 are shown.
  • the grain size in known implants is substantially greater than the grain size of the implants according to FIGS. 2, 3, of the exemplary embodiments according to the invention.
  • the grain size is the mean grain size. This applies to the entire information in the application concerning the particle size.
  • various methods are available which are known to the person skilled in the art, for example the line cutting method, in which the grains which are visible in a flat cut are cut from a measuring line and counted. From the length of the measurement line and the number of grains, the grain size can be determined in a conventional manner.
  • Measurement of the cutting line can be done for example by laser interferometry.
  • the line cutting method is used.
  • the grain size is 200 pm or more. In the implants according to the embodiments of the invention, the grain size is less than 200 ⁇ .
  • FIGS. 1a and 3a The advantage of the invention associated with the smaller grain size or grain refining is illustrated by FIGS. 1a and 3a. There it is shown that the dissolution of the implant material by intergranular corrosion or
  • Implant forms a stent to greatly reduce the web width of the stent, without the grains come in the order of the dimensions of the bridge, in particular the web width.
  • the ratio between the grain size and the ridge width or generally the ratio between the grain size and the width or thickness of the structural element can be adjusted in a range from 1:15 to 1: 100.
  • the range limits can be varied as follows: On the one hand, range limits can be set starting from the limit 1:15, which is 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1 : 50, 1:55, 1:60, 1:65, 1:70, 1:75, 1: 80.
  • the above range limits may be combined with the other limit of 1: 100, respectively.
  • the other range limit may be varied as follows, starting from the ratio 1: 100: 1: 95, 1:90, 1: 85, 1: 80, 1: 75, 1: 70, 1: 65, 1: 60, 1: 55, 1:50, 1:45, 1:40, 1:35.
  • the range limits mentioned above can each be combined with the other range limit 1:15 and, if appropriate, with the restricted range limits emanating from the range limit 1:15.
  • FIG. 1 Another particular feature of the sputtered implant is shown in FIG. It can be seen there that the body 10 of the implant has at least two different first and second regions 11, 12.
  • a region generally refers to a spatial or layered portion of the Implant understood that has substantially homogeneous properties and thereby delimits from another second area. This takes place, as shown in FIG. 4, in the body 10 by the different grain sizes of the grains 18 of the first and second regions 11, 12.
  • the regions 11, 12 formed by sputtering are bonded together in a material-locking manner.
  • the various regions 11, 12 may form layers 13, 14, for example, which are arranged on top of each other, as shown in FIG. 4.
  • the individual layers differ by different grain sizes and / or by different materials.
  • two layers may be provided which are prepared by coating a base body or as a cantilever structure by sputtering or another PVD method.
  • the layer thickness of the individual layer 13, 14 is adjusted in a manner known per se by applying a suitable number of layers of material to one another during sputtering, until the desired layer thickness has been reached.
  • a substantially uniform average grain size is set per material layer, so that the resulting layer is distinguished by the grain size from another layer, which is also produced by sputtering and applying a suitable number of material layers.
  • the various layers 13, 14 form at least part of the wall of the implant or the complete wall of the implant.
  • the webs are constructed of such layers, which have different rates of dissolution.
  • the structure in layers is possible with the sputtering technique unlike conventionally produced pipes.
  • the stent can be
  • the implant in particular the stent, may comprise at least one layer or a basic structure of a material which is not bioabsorbable, so that a implant structure which is weaker in comparison to the implant prior to implantation, ie with a smaller wall thickness, remains in the body, if desired .
  • the complete implant especially the complete stent, can be made entirely from bioabsorbable materials consist of or consist of a fully bioabsorbable material, so that a complete dissolution of the stent is achieved after a predetermined time.
  • the layers may comprise an outer layer 13 and an inner layer 14 or a first layer and a second layer, wherein the grain size of the material of the outer layer 13 is smaller than the grain size of the material of the inner layer 14.
  • the outer layer is arranged so that these in the implanted state with the vessel wall or generally with
  • Body fluid comes into direct contact. It can be provided that the inner layer is coated on both sides with an outer layer, so that the inner layer does not come into direct contact with body fluid at least until the outer layers are dissolved. It can do more than one
  • Inner layer 14 may be provided which have different grain sizes.
  • the outer layer 13 has a fine-grained structure and thus forms a relatively slow-dissolving structure. It is also possible to reverse the dissolution behavior such that a layer having a coarse-grained texture is arranged as the outer layer, so that the
  • Dissolution rate is initially relatively fast, until the outer layer is dissolved, and then slows down when the finer-grained inner layer after dissolution of the outer layer comes into contact with the body fluid.
  • the inner layer it is possible to form the inner layer as a core layer with a fine-grained structure, which is coated on both sides with outer layers of a relatively coarse-grained microstructure. It can also be provided more than one inner layer.
  • the grain size of the material of the respective layer may increase with increasing distance from the outer layer.
  • the outer layer is relatively fine-grained
  • the first layer arranged further inside has a structure with a slightly larger grain size than the outer layer
  • a second layer arranged on the first layer has a structure whose grain size is greater than the grain size of the first layer is etc.
  • This layer structure can be reversed such that the grain size of the material of the respective layer decreases with increasing distance from the outer layer.
  • the dissolution rate increases as the resolution progresses.
  • the dissolution rate slows down with increasing resolution.
  • FIG. 5 shows a stent with a grid structure.
  • the stent has a body 10 with a plurality of structural elements 15, 16, which in the present case are designed as lattice webs. Different structural elements form different regions with different particle sizes, which are characterized by different line thicknesses.
  • the various regions 11, 12 so-called graded layers in which the grain size, in particular the average grain size between the layers changes continuously.
  • a transition layer or a transition region is arranged, in which the mean grain size changes continuously.
  • the continuously changing grain size of the transition region leads to a continuous transition of the two layers.
  • the physical properties between the two layers change continuously. This particularly concerns the dissolution rate.
  • the transition region is designed so that in the transition region there is at least one mean grain size that lies between the different average grain sizes of the two regions or layers that are connected by the transition region.
  • the larger the transition area is formed i. the greater the distance between the two layers of different grain sizes, the more gradual, i. the more uniform the change of the mean grain size in the transition region can be adjusted.
  • the distance between the layers can vary from
  • any measuring method may be used to determine the grain size, provided that the grain size is determined by a uniform method.
  • the per se known line-cutting method is used to determine the mean grain size.
  • the transition region with the continuously changing average grain size can be produced by a PVD process, in particular by sputtering, by using the process parameters of the sputtering process, which are the average particle size
  • a further preferred embodiment which can be combined with the graded layers and / or with the abruptly passing layers, relates to an implant in which the outer layer 13 encloses the inner layer 14,
  • the layers may for example be realized in the form of lattice structures, in particular in the form of webs of a
  • Stents having radially inward a first region having a first grain size and radially outward in the form of a cladding a second region having a second other grain size.
  • the radially outwardly disposed second area completely encloses the first area.
  • Layers have different particle sizes. Seen in cross-section, correspondingly embodied grid structures have a core area (first area) which is enveloped on the outside by a second area, the two areas having different grain sizes. It is also possible to arrange several outer layers around the core area, each having different grain sizes. All features of the other embodiments disclosed in this application, in particular all grain size features, are also disclosed and claimed in the context of this embodiment. In particular, the embodiment with the fully enclosed inner region of the web or the lattice structure can also be advantageous in combination with graded layers, that is, with continuous material transitions.
  • the cladding of a core layer or a core area has the advantage, in contrast to laminated layers in which the sides of the layers are accessible, that a uniform corrosion behavior and thus a controllable dissolution rate are established. For laminates that are open on one side (laminate), corrosion can take place between the layers.
  • the concept of the coated regions or layers having different particle sizes is generally applicable to latticed implants in which a part of the lattice structure or a part of the elements forming the lattice structure is designed as explained above.
  • the elements may include lands, connectors, bridges or other elongated, curved or straight elements of the grid structure.
  • the coated layers can be produced, for example, by the process for producing structured layers according to DE 10 2006 029 831, the contents of which are incorporated by reference in their entirety into this application.
  • a first layer having a first grain size is applied, inter alia, to a substrate or to a composite of sacrificial layers.
  • a second layer is applied with a different grain size, which is patterned for example by etching such that only the second layer is partially removed on both sides.
  • the first lower layer projects laterally beyond the second upper layer on both sides.
  • the corresponding method according to DE 10 2006 029 831 is shown in FIGS. 12 to 17.
  • crystalline material with different particle sizes in particular at least two biodegradable regions of crystalline material with different particle sizes, are provided for setting different dissolution rates of the different regions. There may be 3, 4, 5 or more areas, each having different dissolution rates.
  • the different areas in the radial direction of the elements i. generally in the thickness direction, and / or longitudinally arranged.
  • the different regions with the different grain sizes may consist of the same material, in particular magnesium or a magnesium alloy. Suitable magnesium alloys are known to the person skilled in the art. It is also possible to use different materials for the different areas. Both alternatives are disclosed in connection with all embodiments and in connection with the invention in general.
  • the implant may comprise stents or stent-like implants, filters, in particular filters with a stent-like holding section, flow dividers, occluders, coils, or devices which minimize the blood flow or guide it to other collateral vessels, eg.
  • the body of the implant may have a lattice structure.
  • the grid structure may comprise a laser-cut or a braided grid structure. In the latter case, wires form the body of the implant.
  • the body of the implant may have a lattice structure.
  • the grid structure may comprise a laser-cut or a braided grid structure. In the latter case, wires form the body of the implant.
  • Implant can also form a functional element of the implant, for example, a filter section.
  • the grid structure or the body can form a wall of the implant.
  • the implant wall can be curved and can in particular be adapted to at least partially come into contact with a vessel wall when the implant is inserted into a vessel.
  • the implant can also be a graft in which either the cover or the grid structure or both consist of the biodegradable material. It may also be that the cover and the grid structure have different grain sizes. However, it may also be that the different area both occur in the coverage area or in the grid structure.
  • the invention can be applied to the entire implant or to a part of the implant. For example. In the case of a stent combined with a filter, it is possible to control the dissolution rate such that only the filter, or in general only the functional element, dissolves after the end of the application.

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  • Health & Medical Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Veterinary Medicine (AREA)
  • General Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Vascular Medicine (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • Public Health (AREA)
  • Biomedical Technology (AREA)
  • Epidemiology (AREA)
  • Surgery (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Cardiology (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Prostheses (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials For Medical Uses (AREA)
  • Transplantation (AREA)

Abstract

L'invention concerne un implant médical pour une implantation endovasculaire, comprenant un corps (10) présentant une structure en réseau, compressible et extensible, qui comprend un matériau biodégradable à base d'un alliage de magnésium. L'invention est caractérisée en ce que l'alliage de magnésium est sursaturé d'au moins un composant d'alliage et qu'il est obtenu par pulvérisation d'une ou de plusieurs cibles, dont le matériau contient les composants de l'alliage de magnésium, et par dépôt sur un substrat du matériau cible transféré en phase gazeuse pour former une structure de matériau, de façon que le composant d'alliage sursaturé se présente sous forme de solution solide.
EP11741104.1A 2010-07-14 2011-07-14 Implant médical et procédé de fabrication d'un tel implant Withdrawn EP2593151A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102010027124A DE102010027124A1 (de) 2010-07-14 2010-07-14 Medizinisches Implantat und Verfahren zur Herstellung eines solchen Implantats
PCT/EP2011/003520 WO2012007169A1 (fr) 2010-07-14 2011-07-14 Implant médical et procédé de fabrication d'un tel implant

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EP2593151A1 true EP2593151A1 (fr) 2013-05-22

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DE102013004625A1 (de) * 2013-03-16 2014-09-18 Universitätsklinikum Freiburg Bioresorbierbarer Stent
CN115671399B (zh) * 2022-11-22 2024-01-30 同光(昆山)生物科技有限公司 一种具有双重保护层的医用含镁植入物及其制备方法
CN117448741B (zh) * 2023-12-26 2024-03-22 泓欣科创生物科技(北京)有限公司 一种控制生物医用材料镁合金降解速率的涂层的制备方法及生物医用材料镁合金

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Publication number Priority date Publication date Assignee Title
DE10118541A1 (de) 2001-04-14 2002-10-17 Alstom Switzerland Ltd Verfahren zur Abschätzung der Lebensdauer von Wärmedämmschichten
DE502005008226D1 (de) * 2004-09-07 2009-11-12 Biotronik Vi Patent Ag Endoprothese aus einer Magnesiumlegierung
DE102005003188A1 (de) * 2005-01-20 2006-07-27 Restate Patent Ag Medizinisches Implantat aus einer amorphen oder nanokristallinen Legierung
DE102005018356B4 (de) 2005-04-20 2010-02-25 Eurocor Gmbh Resorbierbare Implantate
US20070050009A1 (en) 2005-08-30 2007-03-01 Aiden Flanagan Bioabsorbable stent
DE102006029831A1 (de) 2006-06-27 2008-01-03 Acandis Gmbh & Co. Kg Verfahren zur Herstellung strukturierter Schichten aus Titan und Nickel
DE102008042576A1 (de) * 2008-10-02 2010-04-08 Biotronik Vi Patent Ag Biokorrodierbare Magnesiumlegierung
DE102008054920A1 (de) * 2008-12-18 2010-07-01 Biotronik Vi Patent Ag Implantat sowie Verfahren zur Herstellung einer Schichtstruktur
DE102009004188A1 (de) * 2009-01-09 2010-07-15 Acandis Gmbh & Co. Kg Medizinisches Implantat und Verfahren zur Herstellung eines solchen Implantats
US8435281B2 (en) * 2009-04-10 2013-05-07 Boston Scientific Scimed, Inc. Bioerodible, implantable medical devices incorporating supersaturated magnesium alloys
DE102009023371A1 (de) 2009-05-29 2010-12-02 Acandis Gmbh & Co. Kg Verfahren zur Herstellung eines medizinischen Funktionselements mit einer freitragenden Gitterstruktur

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WO2012007169A1 (fr) 2012-01-19

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