EP2344087A1

EP2344087A1 - Implant for fusing spinal column segments

Info

Publication number: EP2344087A1
Application number: EP09763887A
Authority: EP
Inventors: Peter Weiland; Rudolf Wenzel
Original assignee: Advanced Medical Technologies GmbH
Current assignee: Advanced Medical Technologies GmbH
Priority date: 2008-11-07
Filing date: 2009-11-05
Publication date: 2011-07-20
Also published as: DE102009014184A1; MX2011004701A; CA2742890A1; IL212722A0; US20110224796A1; WO2010052283A1; JP2012508048A; BRPI0921345A2

Abstract

The invention relates to an optical lens shaped into the form of a shroud and having a light-permeable front side (11) and a side wall (12) adjacent thereto, wherein the side wall (12) and the front side (11) constitute different components of the optical lens (1) that are bound together through injection molding.

Description

Implant for fusion of spinal segments

description

The invention relates to a monolithic implant for fusion of spinal segments, according to the feature combination according to claim 1.

Spinal fusion implants are well known in the art.

WO 2006/079356 A1 discloses, for example, an implant for transforaminal interbody fusion of lumbar spinal segments, in which an attachment part is designed on or in the implant, which is designed as a swivel joint, so that the implantation process can be carried out more easily by means of an auxiliary device. In this case, the implant body is preferably formed from a bioelastic plastic, in particular polyether ether ketone (PEEK), the sickle-shaped implant body having at least one filling opening for large-volume uptake of bone substance between the sickle walls.

However, it is also known to produce such implants made of metal, in particular of titanium. Although this material basically allows coalescence with surrounding bone and tissue structures, it is not yet to such an extent that operators consider the properties of this implant material to be fully mature.

The production of a dental implant consisting of titanium is described, for example, in DE 103 15 563 A1. Here, the implant structure has a prefabricated basic body for connecting the implant structure to the dental implant and an individually adapted main body. The invention aims at forming the main body by sintering or melting layers of material present on the main body in powder form by means of laser sintering and / or laser melting. Preferably, titanium or a titanium-containing powder or a powder of a titanium alloy is used as the material in powder form. From the foregoing, it is the object of the present invention to provide an implant for fusion of spinal segments, which increases in an improved manner to the directly related to the surface of the implant bone and tissue material and at the same time is constructed so that a fast and cost-effective production of the implant can be done.

The object is achieved by a monolithic implant for fusion of spinal segments, according to the feature combination according to claim 1 and a method for producing the monolithic implant, according to claim 23, wherein the dependent claims represent at least expedient refinements and developments.

According to the invention, at least parts of the surface of the implant have a structure-forming porosity and the volume of the implant has a high density. Furthermore, the implant volume comprises a number of directionally oriented and / or randomly arranged, pointing in different directions passages, wherein the passages surrounded by, the strength of the implant increasing, stabilizing surfaces are limited and / or interrupted.

Due to the partially structure-forming porosity of the surface of the implant, surrounding bone, cartilage or tissue material can grow together more easily with the implant. Porosity in this context is to be understood not only as a simple presence of small channels in the millimeter or M ikrometerbereich on a basically smooth surface, but also as a non-uniform material arrangement, which is accompanied by the presence of a Rauheitsmaßes.

The porosity is formed only on the surface of the implant, so that the implant backbone also has a high density. The inner surfaces of the passages expediently likewise have the structure-forming porosity. The subareas of the implant volume which comprise directionally oriented and / or arbitrarily arranged passages pointing in different directions are expediently formed over as large a stability-harmless area as possible. This results in a relatively large implant surface area, which is provided with openings. Through these openings, the bone and tissue material can also form a connection with the implant.

The passages are expediently formed on both sides. Ie. Passages are provided on both the top and bottom of the implant. As the top and bottom of the implant, the surfaces of the implant are referred to, which point to the vertebral bodies adjacent in the implanted state.

A number of side-by-side directionally-oriented and / or randomly-spaced, multi-directional passageways are surrounded, bounded and / or interrupted by stabilizing surfaces so that the strength of the implant is guaranteed despite the presence of the passageways. In this case, for example, the edge of the implant can be completely formed as a stabilizing surface. Further embodiments further provide a stabilizing surface which divides the total area of the passages arranged with a number of adjacent direction-oriented or randomly arranged passageways into two partial areas.

Preferably, the described directionally oriented or randomly arranged passageways are formed as a honeycomb structure. These hexagonal cavities represent an optimum ratio of the area of the passageway created thereby and the strength of the cavity defining structure.

However, it is also conceivable to form the passages by nested web connections or to form the passages in the form of cylindrical channels, wherein the circular cylindrical shape represents a geometrically in this context, the simplest to be formed embodiment. Starting from the largest surface side of the monolithic implant, the passages expediently extend in the vertical direction. In a particularly preferred embodiment of the present invention, the passageways are interrupted in their directional course of at least one free space. This material-saving construction improves the elasticity of the implant when exposed to acting on the largest surface side forces.

The clearance may be provided in the region of the center of the implant thickness, wherein implant thickness is considered in this context as the measure which describes the distance between two vertebrae adjoining the implant from above and below.

In addition, it is conceivable that the passageways are interrupted in their directional course of at least one stabilizing surface.

But also an arbitrary arrangement of the passages, as already described, possible. That is, the passages do not have a predetermined direction in their entirety, but are apparently arranged completely randomly next to and above each other. Such passageway formation is most similar to the natural structure of cancellous bone. The arbitrarily arranged passages can also be interrupted in their course by a free space or a stabilizing surface.

The side surfaces and / or edges of the implant, which first come into contact with surrounding bone, tissue or cartilage material during the implantation process, preferably have a surface which is smoother compared to the surfaces of the implant having a structure-forming porosity. This greatly improves the implantation process, since the implant does not "rub" against surrounding bones and tissue parts and, on the one hand, does not injure them and, on the other hand, facilitates insertion into the space created by the removal of an intervertebral disc. Depending on the area of application and the surgical procedure used, the implant may have different basic shapes.

Thus, for example kidney-shaped, crescent-shaped, pin-shaped and cuboid basic shapes are conceivable, the kidney-shaped basic shape is used in the fusion of vertebral bodies in the lumbar vertebrae and the pin-shaped basic shape in the supply of the cervical vertebrae or lumbar vertebrae is suitable. The crescent-shaped basic shape is suitable in a special way in a so-called. TLIF surgical technique.

In addition, the monolithic implant preferably has a slightly indicated wedge-shaped profile in order, on the one hand, to facilitate the implantation procedure and, on the other hand, to do justice to the curved shape of the spinal column.

The surfaces of the implant which have a structure-forming porosity have a roughness of 150 μm to 400 μm. An average roughness of 200 μm was determined as a particularly preferred measure.

The monolithic implant also has at least one bore for fixation of surgical instruments, so that the implant can be conveniently inserted into the spine.

In addition, at least one opening in the implant is provided, which serves for the application of bone substitute material or pastes. The openings are mounted in such a way that in the implanted state access to the openings by means of cannulas, syringes or similar aids is given. Of particular importance is the addition of bone graft material, which provides improved implant growth to the surrounding spinal segments.

The illustrated monolithic implant for fusion of spinal segments is suitable for implantation by means of the Posterior Lumbar Intervertebral Fusion Surgical Technique (PLIF), depending on the size and selected basic shape, as well as for implantation by means of the anterior lumbar intervertebral fusion technique. Surgical Technique (ALIF) and implantation using the thoracolumbar intervertebral fusion surgical technique (TLIF). Thus, the great advantages of the present invention, namely, improved implant growth to the surrounding bone and tissue structures can be utilized with improved stability of the implant in full spine surgery.

In a particularly preferred embodiment, the monolithic implant is constructed in such a way that initially there is a basic body specified with respect to the geometric dimensions of the implant, so that the stability of the implant and adaptation to the general anatomical specifications of the subregion of the spinal column to be treated are always present. In addition, partial areas of the implant are referred to as so-called. Defines configuration segments, which are variably modifiable according to the different customer requirements, since these configuration segments are harmless in terms of stability and can be, for example, reduced or implanted in a modified geometric form. For example, the surgeon can determine the dimensions of the tip of an implant with a pin-shaped basic shape. The implant can thus be fabricated according to the surgical habits of the surgeon and any anatomical abnormalities of the patient.

The monolithic implant according to the invention is produced in the course of a sintering process and / or electron beam melting process, the sintering process and the electron beam melting process each comprising a plurality of steps. First, the geometry data of the implant must be present three dimensionally and processed as a cross-sectional data, so that a gradual fusion of sintered material applied to a base plate in the form of successive horizontal cross sections by means of energy deposition by a radiation source and appropriate cooling after the application of energy and the fusion of a powder layer. For each individual cross-sectional layer, a thin layer of powder is first applied to the base plate, the sintering powder being dispensed by a powder dispenser and smoothed out with the aid of a roller or a doctor blade. The powder layer is then by means of Energiebeaufschlagu ng fused by a radiation source according to the respective dimensions of the cross-sectional layer and cooled in the subsequent. The energy emitted by the radiation source only strikes the powder particles, which are to be solidified, ie represent a material particle of the later implant. Subsequently, the next cross-sectional layer is applied to the lowered base plate or the already fused material and in turn melted by applying energy. The processing is done layer by layer in the vertical direction.

The sinter powder used in the illustrated method is, for example, a titanium powder. This material is a standard material in the manufacture of implants and impresses above all by its biocompatibility and high stability.

However, it is also conceivable to use powdered titanium alloys, ceramic powder or polyetheretherketone powder.

The radiation source of the production method is preferably a laser source, but the use of an electron beam source is also conceivable. When using a laser source u. a. more precise structures than are produced with an electron beam source. The selection with regard to the radiation source to be used thus depends, for example, on the respective geometric shape of the monolithic implant.

The already mentioned side surfaces and / or edges of the implant with a smooth surface can be made after the sintering process by a post-processing by means of milling, polishing or lathes.

The stated production method is particularly suitable for the production of multiple implants with different dimensions in a sintering process. Unlike conventional production methods such. As the milling must be converted in the process according to the sintering method no tools according to the dimensions of the workpiece to be produced or unterschiedl iche programs are loaded in the CNC milling. Therefore always can only the implants are made, which are actually needed and it must not be produced in a workflow several implants with identical dimensions and then stored.

If a doctor wishes to order a monolithic implant with specific wishes with regard to the variably configurable configuration segments, another aspect of the invention provides that he enters these dimensions in a predefined mask on a website and transmits these data to the manufacturer by means of data transmission and there Data are converted into the required cross-layer data, which in turn are sent by data transmission to the sintering plant and there the implant is produced by means of sintering.

After just a few days, the customer receives the custom-made implant and does not have to accept long delivery times, as is usual practice with implants specially made to customer specifications.

The invention will be explained in more detail below with reference to several embodiments and with the aid of figures.

Hereby show:

1 shows a representation of a monolithic implant in kidney shape;

FIG. 2 is an illustration of a monolithic implant in stick form; FIG.

3 shows a representation of a monolithic implant in cuboid shape;

4 shows an illustration of a monolithic implant in sickle shape;

Fig. 5 is a vertical sectional view of a kidney-shaped monolithic implant and Fig. 6 is a vertical sectional view of a cuboid monolithic implant.

In Fig. 1, a substantially kidney-shaped monolithic implant for fusion of spinal segments is shown. Clearly visible are the directional passages 1, which are shown in the following representations in the form of a honeycomb structure.

The direction-oriented passages 1 are on the one hand surrounded by a stabilizing surface 2, wherein the total number of Richtu ngsorientierten passages 1 are also interrupted by a further stabilizing surface 2. In the figures, the structure-forming porosity of the surface is not shown, which is also on the inner surfaces of the honeycomb structure.

The stabilizing surfaces 2 have the purpose of giving the implant, despite the high number of directional passages 1 sufficient strength for permanent residence in the human body.

In the example shown, the directionally oriented passages 1 extend in the vertical direction starting from the largest surface side 3 of the monolithic implant.

The bore 4 or the openings 5 on the side surface of the implant are intended, on the one hand, for the fixation of surgical aids during the operation and, on the other hand, for the application of bone substitute material or pastes.

The illustrated kidney-shaped basic shape 6 is particularly suitable when using the so-called. ALIF surgical method.

2, a monolithic implant with a pin-shaped basic shape 7 is shown. Also in this embodiment, a large part of the implant volume is provided with directional passages 1. Conspicuous here are the side surfaces 2, which do not completely limit the number of directionally oriented passages 1 on the side region of the implant, but provide only in the middle of the implant thickness through a narrow web 8 for additional stability. For easier introduction during the implantation process, this monolithic implant has a tip 9. The tip 9 in this case has a smoother surface compared to the surfaces with structuring porosity, since the tip first comes into contact with surrounding bone, cartilage, and tissue materials during the implantation process. Due to the smooth surface, the implantation process can be additionally facilitated. This implant example can be used especially in the PLIF surgical method.

FIG. 3 shows an exemplary embodiment with a cuboidal basic shape 10, wherein, as already shown in FIG. 2, the directionally oriented passages 1 have stabilizing surfaces in the form of a web 8 only in the area of the center of the implant thickness.

A crescent-shaped basic shape 11 of the monolithic implant shows the illustration of FIG. 4 and can be implanted in the TLIF surgical method.

The sectional view (FIG. 5) of an implant with kidney-shaped basic shape 6 shows that the passageways 1 are interrupted in their directionally oriented course by a free space 12. The space 12 serves, on the one hand, to save material and, on the other hand, to increase the elasticity when a force acts on the surfaces of the implant.

As shown in Fig. 6, the directional passages 1 can be interrupted in its course not only by a free space 12, but also by a stabilizing web 8.

The illustrated monolithic implants for fusion of spinal segments have been produced in the illustrated embodiments by an electron beam melting method or a laser sintering method. Titanium powder was used as sinter powder. Due to the sintering process, surfaces with a structure-forming porosity achieved, this surface design also affects the inner surfaces of the passages. A surface roughness of 42 μm was achieved.

LIST OF REFERENCE NUMBERS

1 direction-oriented passages

2 stabilizing surface

3 largest surface side

4 hole

5 opening

6 kidney-shaped basic form

7 pencil-shaped basic shape

8 footbridge

9 tip

10 cuboid basic shape

11 crescent-shaped basic shape

12 free space

Claims

claims

1. A monolithic implant for fusion of spinal segments, wherein at least parts of the surface of the implant have a structure-forming porosity,

- The volume of the implant has a high density, continue

- The implant volume comprises a number of directionally oriented and / or arranged arbitrarily, pointing in different directions passages (1) and

- The passages (1), the strength of the implant increasing, stabilizing surfaces (2) are surrounded, limited and / or interrupted.

2. Monolithic implant according to claim 1, characterized in that the passages (1) are formed in the form of a honeycomb structure.

3. Monolithic implant according to claim 1 or 2, characterized in that the passages (1) are formed by nested web connections.

4. Monolithic implant according to one of claims 1, 2 or 3, characterized in that the passages (1) are formed in the form of cylindrical channels.

5. Monolithic implant according to one of the preceding claims, characterized in that the passages (1) extend from the largest surface side (3) of the monolithic implant in the vertical direction.

6. Monolithic implant according to one of the preceding claims, characterized in that the passages (1) are interrupted in their course of at least one free space (12).

7. Monolithic implant according to claim 6, characterized in that the free space (12) is provided in the region of the center of the implant thickness.

8. Monolithic implant according to one of the preceding claims, characterized in that the passages (1) are interrupted in their course of at least one stabilizing surface (2).

9. monolithic implant according to one of the preceding claims, characterized in that the side surfaces and / or edges of the implant, which come in the implantation process first with surrounding bone, tissue and cartilage material in contact, over a compared to the surfaces of the implant have a structure-forming porosity, smoother surface.

10. Monolithic implant according to one of the preceding claims, characterized in that the implant has a substantially kidney-shaped basic shape (6).

11. Monolithic implant according to one of claims 1 to 9, characterized in that the implant has a substantially pin-shaped basic shape (7).

12. Monolithic implant according to one of claims 1 to 9, characterized in that the implant has a substantially cuboidal basic shape (8).

13. Monolithic implant according to one of claims 1 to 9, characterized in that the implant has a substantially crescent-shaped basic shape (11).

14. Monolithic implant according to one of the preceding claims, characterized in that the implant has a wedge-shaped profile.

15. Monolithic implant according to one of the preceding claims, characterized in that the surfaces of the implant having a struktu rbildenden porosity have a roughness of 150 microns to 400 microns.

16. Monolithic implant according to one of the preceding claims, characterized in that the surfaces of the implant having a struktu rbildenden porosity have a roughness of 200 microns.

17. Monolithic implant according to one of the preceding claims, characterized in that the implant has at least one bore (4) for the fixation of surgical instruments.

18. Monolithic implant according to one of the preceding claims, characterized in that the implant has at least one opening (5) for application of bone substitute material or pastes.

19. Monolithic implant according to one of the preceding claims, characterized in that the implant is used in an implantation, which is performed by means of the posterior lumbar intervertebral fusion surgical technique is used.

20. Monolithic implant according to one of claims 1 to 18, characterized in that the implant in an implantation, which is performed by means of the anterior lumbar intervertebral fusion surgical technique, is used.

21. Monolithic implant according to one of claims 1 to 18, characterized in that the implant is used in an implantation, which is carried out by means of the thoracolumbar intervertebral fusion surgical technique.

22. Monolithic implant according to one of the preceding claims, characterized in that the implant consists of a specified with respect to the geometrical dimensions of the implant base body and according to customer requirements variably configurable configuration segments.

23. A method for producing a monolithic implant according to one of claims 1 to 22, characterized in that the implant is produced in the course of a sintering process, wherein the three-dimensional shape of the monolithic implant by stepwise fusion of deposited on a base plate sintered material in the form of successive horizontal cross sections takes place by energization by a radiation source and appropriate cooling after the application of energy and the fusion of a powder layer.

24. The method according to claim 23, characterized in that it is the sintered material is a titanium powder.

25. The method according to claim 23, characterized in that it is the sintered material is a powdered titanium alloy.

26. The method according to claim 23, characterized in that the sintered material is a ceramic powder or polyetheretherketone powder.

27. The method according to any one of claims 23 to 26, characterized in that it is at the radiation source is a laser.

28. The method according to any one of claims 23 to 26, characterized in that it is at the radiation source is an electron beam source.

29. The method according to any one of claims 23 to 28, characterized in that the side surfaces and / or edges of the implant are achieved with a smooth surface after the sintering process by a post-processing milling, polishing or turning operation.

30. The method according to any one of claims 23 to 29, characterized in that a plurality of implants are produced with different dimensions in a sintering charge.

31. The method according to any one of claims 23 to 30, characterized in that the three-dimensional dimensions of the implant to be produced, comprising the dimensions of the customizable customizable configuration segments, are entered into a mask on a website, transmitted by data transfer to a host and into individual Cross-section data are converted and sent by data transfer to the sintering plant and there the implant is produced by sintering.