Method for Producing a Biocompatible Implant, and Implant

Abstract

The present invention provides a method for producing a biocompatible implant and a corresponding biocompatible implant. The biocompatible implant (10) has an implant body (8) composed of a polyaryletherketone plastic, wherein the implant body (8) has at least one first porous section (12) and one second porous section (13), wherein the first porous section (12) and the second porous section differ with respect to their porosity.

Claims

1. A method for producing a biocompatible implant, comprising the following steps: providing a plastics powder composed of a polyaryletherketone; heating and pressing the plastics powder to form at least one intermediate piece; mechanically comminuting the at least one intermediate piece to form a granular material; and thermally bonding the granular material in a mold to form an implant, wherein the at least one granular material is exposed to a spatially inhomogeneous heat distribution during the thermal bonding, wherein the implant has an implant body having at least one first porous section and one second porous section, wherein the first porous section and the second porous section differ with respect to their porosity.

2. The method as claimed in claim 1, wherein the mold is heated with a plurality of heating devices which are each activated separately during the thermal bonding of the granular material in order to produce the inhomogeneous heat distribution.

3. The method as claimed in claim 1, wherein the polyaryletherketone is polyetheretherketone.

4. The method as claimed in claim 1, wherein the granular material comprises particles having a round, rounded, partially angular or polygonal cross section.

5. The method as claimed in claim 1, wherein the granular material comprises particles having a round cross section.

6. The method as claimed in claim 1, wherein, before the preparation of the granular material, the plastics powder is subjected to an antimicrobial treatment and/or a bioactive component is admixed in the plastics powder.

7. The method as claimed in claim 1, wherein the granular material has a particle size of between 1 ?m and 3000 ?m.

8. The method as claimed in claim 1, wherein the mold is filled with a plurality of granular materials differing with respect to their particle size and/or particle shape before the thermal bonding of the granular material.

9. The method as claimed in claim 1, wherein the mold exerts a specifiable pressure on the at least one granular material during the thermal bonding of the granular material.

10. The method as claimed in claim 1, wherein the mold comprises a shaping means which forms a cavity within the implant body during the thermal bonding of the granular material.

11-24. (canceled)

Description

[0042] In the figures:

[0043] FIG. 1 shows a schematic flow chart of one embodiment of the method according to the invention for producing the implant comprising the method steps S1 to S4;

[0044] FIG. 2 shows a cross-sectional view of an open mold that is being filled with granular material;

[0045] FIG. 3 shows a side view of the mold according to FIG. 2 in the closed state after the production of the implant body;

[0046] FIG. 4 shows a sectional side view of a first embodiment of an implant body having a plurality of layers and differently porous sections;

[0047] FIG. 5 shows a sectional side view of a further embodiment of an implant body having a solid outer layer;

[0048] FIG. 6 shows a sectional side view of a further embodiment of an implant body in the structure of which a cavity is formed;

[0049] FIG. 7 shows a sectional side view of a partial detail of the embodiment according to FIG. 6;

[0050] FIG. 8 shows a sectional side view of one embodiment of the implant body of the implant having a porous surface and porous sections composed of a hexagonal granular material with admixtures; and

[0051] FIG. 9 shows a sectional side view of one embodiment of the implant body of the implant having a porous surface and porous sections composed of a pentagonal granular material with admixtures.

[0052] In all the figures, identical or functionally identical elements and devices have been provided with the same reference signs, unless otherwise stated.

[0053] FIG. 1 shows a schematic flow chart of one embodiment of the method according to the invention for producing the implant comprising the method steps SI to S4.

[0054] According to FIG. 1, there is first provided a plastics powder 2 in the form of a PEEK powder 2 (step S1). The free-flowing plastics powder 2 is then pressed by means of a sintering-like process, as identified by step S2. This forms one or more one-piece/coherent intermediate pieces 4. In particular, the intermediate pieces 4 are achieved by pressing and simultaneously heating the plastics powder 2, the intermediate pieces 4 ultimately forming rectangular plates. The temperature of the intermediate pieces 4 during this sintering/primary shaping of the intermediate pieces 3 is always below the decomposition temperature of the plastics powder 2 used (or, in the case of multiple plastics materials, below the decomposition temperature of the material component of the plastics powder 2 used that has the lowest melting point). Preferably available for producing an intermediate piece 4 is a negative form, into which the plastics powder 2 is first filled and then heated up and also compressed with exposure to a pressing force, with the result that an intrinsically solid structure is formed in the form of the intermediate pieces 4.

[0055] Following the production of the intermediate pieces 4, each intermediate piece 4 is comminuted in a defined manner according to step S3. The intermediate pieces 3 are comminuted into particles to form a granular material G1. The particles of the granular material Gl have a substantially uniform shape, which is realized by the specific implementation of the mechanical comminution. In this exemplary embodiment, round particles, in the form of spherical particles or particles with an oval cross section, are produced.

[0056] According to step S4, what then follows is thermal bonding of the granular material 4 of set shape to form the individual, one-piece three-dimensional implant body 8. In this exemplary embodiment, the exposure to a spatially inhomogeneous heat distribution from a mold 20 serves for thermal bonding, with the result that two porous sections 12, 13 of differing porosity are formed on the implant body 8 (using a mold not depicted here).

[0057] In this method, after step S4 has been carried out, the implant body 8 has substantially the finished shape of the implant 10 to be produced. Here, the implant 10 is typically in the form of an implant 1 for osteosynthesis or fracture treatment. The thermal bonding is carried out in such a way that the implant 10/implant body 8 has a porous structure, preferably an open-pore structure. Alternatively, closed-pore structures are also realizable.

[0058] Furthermore, it can be seen in FIG. 1 that two heating devices 22a, 22b, which are operated by a controller 24, are arranged on the mold 20. The inhomogeneity of the heat distribution to which the granular material G1 is exposed is achieved by the two separately activated heating devices 22a, 22b, the heating device 22a emitting heat of a temperature T1 and the heating device 22b emitting heat of a temperature T2, with the result that sections 12, 13 having differing porosity are formed on the implant body 8.

[0059] FIG. 2 shows a cross-sectional view of an open mold that is being filled with granular material.

[0060] According to FIG. 2, the mold 20 is filled with two granular materials G1, G2 by a filler 26 in order to carry out the method according to the invention. The first granular material Gl having a round cross section is already arranged in the mold bed 23 arranged on the lower heating device 22b, and the filler 26 is now differentially filling the mold bed 23 with another granular material G2, the granular shape of which has a different cross section, namely a hexagonal cross section.

[0061] FIG. 3 shows a side view of the mold according to FIG. 2 in the closed state after the production of the implant body.

[0062] In FIG. 3, it can be seen that the mold 20 is closed and the implant body 8 of the implant 10 has been formed as a result of exposure to the inhomogeneous temperature distribution from the heating devices 22a, 22b, controlled by the controller 24, which implant body 8 can be demolded from the mold 20 after the latter has been opened.

[0063] FIG. 4 shows a sectional side view of a first embodiment of an implant body having a plurality of layers and differently porous sections.

[0064] In FIG. 4 is an implant body 8 having a plurality of layers L1, L2, L3, of which layer LI, which is lowermost for the observer, is solid and thus nonporous. In the present case, said layer LI forms an outer layer that at least partially delimits the implant body 8 and differs structurally from further, inner layers L2, L3. In the upward direction for the observer, there follow said further layers L2, L3 of differing porosity, layer L2 having a porosity in the range of 10-20% and layer L3 having a porosity in the range of 20-40%. As a result, layers L2 and L3 form porous sections 12, 13 of the implant body 8 of differing porosity and thus form a porosity gradient.

[0065] FIG. 5 shows a sectional side view of a further embodiment of an implant body having a solid outer layer.

[0066] The implant body 8 has a porous outer region as first section 13, which is formed with a lower porosity than that of a porous inner region as second section 12.

[0067] FIG. 6 shows a sectional side view of a further embodiment of an implant body in the structure of which a cavity is formed.

[0068] What can be seen in FIG. 6 is a cross section of an implant body 8, which again has a porous outer region as a section 13, which encloses another section 12 as an inner region of higher porosity. Within its structure, the implant body 8 is provided with a cavity 16 having an oval cross section. Accommodated in the cavity is a bioactive substance 18 in the form of a hydrogel which promotes tissue regeneration. The cavity 16 has a transverse extent of a few millimeters.

[0069] FIG. 7 shows a sectional side view of a partial detail of the embodiment according to FIG. 6.

[0070] The detail in FIG. 7 shows that the cavity 16 of the implant body 8 is provided with an interface section 17 which connects the cavity 16 to the exterior 19 of the implant 10. What is created as a result is access to the cavity 16, via which the bioactive substance 18 can be deposited in the cavity at a desired moment. Likewise shown is the arrangement on the interface section 17 of a guide means 17a which, as a flange-like cross-sectional constriction of the interface section, allows the application, accommodation or alignment of an injection means, such as a cannula or the like, that is not shown.

[0071] FIG. 8 shows a sectional side view of one embodiment of the implant body of the implant having a porous surface and porous sections composed of a hexagonal granular material with admixtures, and FIG. 9 shows a sectional side view of one embodiment of the implant body of the implant having a porous surface and porous sections composed of a pentagonal granular material with admixtures.

[0072] According to FIG. 8, a hexagonal polyetheretherketone (PEEK) granular material G2 was used, and according to FIG. 9, a pentagonal PEEK granular material G3 was used.

[0073] In addition, the granular materials have each been admixed with different additives before the thermal bonding, a ceramic component in the case of the implant body 8 in FIG. 8 and silver and copper as metals in the case of the implant body 8 in FIG. 9.

[0074] If the powders for producing the granular materials have each undergone a corresponding pretreatment, the resultant pore structures are each intrinsically bioactive, in the present case antimicrobially active. Both implant bodies 8 have a porous surface 30, i.e., they are, as already mentioned, open-pore structures. Their porous sections 12, 13 form interconnecting pore structures with pores in the order of magnitude of a few 100 ?m, which support the ingrowth of biological tissue and increase the strength of the implant 10. The implant 10 is primarily specifically fixed via its porous properties and via the macrostructural properties of its production process.

[0075] Although the present invention has been described above on the basis of preferred exemplary embodiments, it is not restricted thereto, but is modifiable in a variety of ways. In particular, the invention can be altered or modified in many ways without departing from the essence of the invention.