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Publication numberWO2007000061 A1
Publication typeApplication
Application numberPCT/CH2005/000354
Publication date4 Jan 2007
Filing date27 Jun 2005
Priority date27 Jun 2005
Publication numberPCT/2005/354, PCT/CH/2005/000354, PCT/CH/2005/00354, PCT/CH/5/000354, PCT/CH/5/00354, PCT/CH2005/000354, PCT/CH2005/00354, PCT/CH2005000354, PCT/CH200500354, PCT/CH5/000354, PCT/CH5/00354, PCT/CH5000354, PCT/CH500354, WO 2007/000061 A1, WO 2007000061 A1, WO 2007000061A1, WO-A1-2007000061, WO2007/000061A1, WO2007000061 A1, WO2007000061A1
InventorsArmin Studer
ApplicantSynthes Gmbh
Export CitationBiBTeX, EndNote, RefMan
External Links: Patentscope, Espacenet
Method for manufacturing a surgical implant
WO 2007000061 A1
Abstract
A method is provided for manufacturing a surgical implant (1) having a structured surface (2) for improving the growing on of bone tissue. A plurality of cavities (3) are mechanically produced on said surface (2). Said cavities (3) are provided with an undercut (5).
Claims  (OCR text may contain errors)
Claims
1. Method for manufacturing a surgical implant (1) having a structured surface (2) for improving the growing on of bone tissue characterized in that a plurality of cavities (3) are mechanically produced on the surface (2), said cavities (3) being provided with an undercut (5).
2. Method according to claim T, wherein the cavities (3) are produced by means of turning on a lathe or milling.
3. Method according to claim 1 or 2, wherein the cavities (3) have a spherical shape.
4. Method according to claim 3, wherein the radii of the cavities (3) are in the range of 1 ,0 to 2,0 mm.
5. Method according to one of the claims 1 to 4, wherein at least 50% of said cavities (3) have a periphery viewed in a cross-section perpendicular to the surface (2) with a central angle β in the range of 181 to 350.
6. Method according to one of the claims 1 to 5, wherein at least 50% of said cavities (3) have spherical surface portion located within said implant, said spherical surface portions having arcs of great circles with a central arc α in the range of 10 to 179.
7. Method according to one of the claims 1 to 6, wherein the cavities (3) are regularly placed on the surface (2) regarding their position.
8. Method according to one of the/claims 1 to 6, wherein the cavities (3) are irregularly arranged on the surface (2) regarding their position and are preferably placed non- linearly.
9. Method according to one of the claims 1 to 8, wherein portions of the surface (2) are free of cavities (3).
10. Method according to one of the claims 1 to 9, wherein the size of the cavities (3) is different with regard to their position on the surface (2).
11. Method according to one of the claims 1 to 10, wherein the shape of the individual cavities (3) varies.
12. Method according to one of the claims 1 to 1 , wherein the cavities (3) are mutually connected.
13. Implant (1) with a structured surface (2) for improving the growing on of bone tissue, being provided with a plurality of cavities (3) in the surface (2), whereby said cavities (3) are provided with an undercut (5) characterized in that said undercuts (5) have been obtained by mechanical processes only.
14. Implant (1) produced according to the method according to one of the claims 1 to 12.
15. Implant (1) according to claim 13 or 14, wherein said implant comprises a plastic material, preferably PEEK and preferably has a coating of titan.
16. Implant (1) according to one of the claims 13 to 15, wherein said implant is provided with a plastic coating in which the cavities (3) are placed.
17. Implant (1) according to according to one of the claims 13 to 16, wherein said implant is provided with a coating of titan, said coating being preferably deposited by means of cathodic evaporation.
18. Implant (1) according to one of the claims 13 to 17, for use as an intervertebral implant and having two appositional surfaces apt to bear against the end plates of two juxtaposed vertebral bodies and wherein at least the surfaces (2) of said two appositional surfaces are provided with a plurality of cavities (3).
Description  (OCR text may contain errors)

Method for manufacturing a surgical implant

The invention relates to a method for manufacturing a surgical implant according to the concept of claim 1 and to a surgical implant according to the concept of claim 13.

Methods by means of which the surface of a surgical implant is provided with a plurality of cavities, e.g. via chemistry through etching are already known. These known methods have the objective to increase growing on of bone tissue to a surface of the implant accordingly structured. This chemical method shows the disadvantage that location, shape and dimension of the cavities manufactured through etching may not be previously defined. A further disadvantage of this chemical method is that the surface of the implant is damaged through the strongly aggressive etchant.

Other methods use laser techniques in order to structure the surface, whereby no clearly defined cavities are achievable as well.

On this point, the invention intends to provide remedial measures. The invention is based on the objective of providing a method allowing to manufacture a plurality of cavities having an undercut on the surface of an implant, whereby location, shape and dimension of the cavities may be previously selected and determined. This allows to arbitrarily select the retention of the surface.

The invention solves the posed problem with a method including the features of claim 1 , as well as with an implant including the features of claim 13.

Additional advantageous embodiments of the invention are characterized in the subclaims.

The advantages achieved by the invention are essentially to be seen in the fact that thanks to the method according to the invention a clean surface structure for a surgical implant which may be previously manufactured and be provided with cavities in a second step. In a particular embodiment the cavities are manufactured through turning on a lathe or through milling.

The cavities may have a spherical shape, preferably in the form of a spherical layer, truncated spherical sector or spherical segment. The radius of the respective spherical zone or cap is preferably in the range of 1 ,0 to 2,0 mm. Preferably, at least 50% of said cavities have a periphery viewed in a cross-section perpendicular to the surface with a central angle β in the range of 181 to 350. Typically, at least 50% of said cavities have a spherical surface portion located within said implant, said spherical surface portions having arcs of great circles with central angles α in the range of 10 to 179.

In a further embodiment the cavities are arranged regularly with regard to their location on the surface. In another embodiment the cavities are arranged irregularly with regard to their location and are preferably placed non-linearly. The advantage of the non-linear arrangement of the cavities is to be seen in the fact that a perforation of the end plates of the adjacent vertebral bodies through the implant may be prevented.

Preferably, portions of the surface remain free of cavities. The areas without cavities of such implants have a higher mechanical strength. A further advantage is that the areas without cavities may be used for the acceptance of instruments, e.g. for manipulation of the implant.

In a particular embodiment the size of the cavities is different depending on the location of the cavity on the surface. This allows a better adaptation of the structured surface to different bone qualities. For example an intervertebral implant may be provided with larger cavities in the peripheral area, particularly in the lateral and anterior portions of the apposition surface and the central area of the apposition surface may be provided with smaller and preferably more grippy cavities.

In a further embodiment the shape of the individual cavities varies, therewith allowing a better matching to the bone structure.

The cavities may be mutually connected. The implant manufactured according to the method according to the invention may consist of a plastic material, preferably of PEEK. In one embodiment the implant is provided with a coating of titan, preferably manufactured by cathodic evaporation. The implant may also be provided with a synthetic coating at locations where the cavities are positioned.

In a preferred embodiment the implant is built as an intervertebral implant whereby at least the surfaces of the apposition surfaces of the implant that are determined for contacting the end plates of two intervertebral bodies are provided with a plurality of cavities.

The invention and additional configurations of the invention are explained in even more detail with reference to the partially schematic illustration of several embodiments. In the drawings:

Fig. 1 is a longitudinal section through the surface region of a surgical implant with cavities having spherical undercuts according to one embodiment of the invention;

Fig. 2 is a top view on the surface region of the surgical implant shown in fig. 1 ;

Fig. 3 is a longitudinal section through the surface region of a surgical implant with cavities having frusto-conical undercuts according to another embodiment of the invention;

Fig. 4 is a longitudinal section through the surface region of a surgical implant with cavities having undercuts that are shaped spherical/conical according to a further embodiment of the invention; and

Fig. 5 is a longitudinal section through the surface region of a surgical implant with a plurality of cavities having undercuts according to one embodiment of the invention.

The structured surfaces 2 shown in figs. 1 and 2 are related to the surface region of a surgical implant 1 , the surface region here being part of the apposition surface of an intervertebral implant. The smaller and larger cavities 3 are arranged in an irregular manner of the surface 2 and are provided with an undercut 5 as shown in fig. 1. The cavities 3 have been produced by milling in the example presented here and have a spherical shape. The manufacturing of the cavities 3 is effected in a first step via milling of cylindrical spaces and subsequently in a second step by means of a profiled or spherical cutter by means of which the size and the shape of the cavities 3 may be determined. The cavities 3 have the shape of a spherical layer having a spherical surface portion located within said implant, said spherical surface portions having arcs of great circles with central angles α in the range of 20 to 50. Furthermore, the cavities 3 have a periphery viewed in the cross-section perpendicular to the surface 2 with a central angle β in the range of 200 to 300.

Fig. 3 depicts an embodiment of the structured surface 2 wherein the cavities 3 have a conical undercut 5. Therefore the form of the cavities 3 is frusto-conical.

Fig. 4 depicts another embodiment of the structured surface 2 wherein the cavities 3 having a spherical/conical undercut 5. In the example here the general form of the cavities is frusto-conical whereby the edge adjacent the base of the conical frustrum is rounded.

Fig. 5 depicts a further embodiment of the structured surface wherein the cavities 3 have undercuts 5 in the form of a spherical layer, e.g. as shown in fig. 1. Furthermore, the fins 6 of material that are formed between the cavities 3 converge into edges at their free ends.

Patent Citations
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
EP2286767A1 *21 Aug 200923 Feb 2011Jossi Holding AGMethod for producing a structured surface on a workpiece from a metallic material and implant with such a surface
US81401074 Jan 200820 Mar 2012Sprint Spectrum L.P.Method and system for selective power control of wireless coverage areas
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