Trial Implants

Abstract

The present invention relates to a trial implant (10), in particular for spinal surgery, total knee or hip endoprosthesis or shoulder prosthesis, having at least one head (12), at least one reinforcing core (16) and at least one handle (18), the head (12) being manufactured by 3D printing and the head (12) and the handle (18) being made from plastic.

Description

[Technical field]

[0001] The present invention relates to trial implants, for example for spinal surgery, for total knee or hip endoprostheses, or for shoulder prostheses. [Background technology]

[0002] In the case of degenerative lumbar and lumbosacral diseases such as degenerative disc disease, spinal instability, or spondylolisthesis, the spinal segment is surgically strengthened by removing the disc in the affected segment and then inserting an implant, also known as a cage, into the resulting intervertebral space. To insert the cage, it is first necessary to determine the patient-specific dimensions between the two affected vertebral bodies. This is because, for stability reasons, the largest possible cage is preferably implanted to fuse the two vertebral bodies. A trial implant, which is inserted into the intervertebral space during surgery, is used to determine the implant dimensions required. Thus, several different trial implants can be used in succession to determine the best possible dimensions of the cage to be used. The trial implant itself must have a certain strength and shape to ensure that the two adjacent affected vertebral bodies are not (further) injured during insertion into the intervertebral space, alignment within the intervertebral space, and final removal from the intervertebral space. To safely handle the trial implant during sizing of the intervertebral space, the trial implant is typically provided with an elongated handling portion or shank, which must have sufficient tensile, shear, bending, and torsional stiffness. The entire trial implant, i.e., including the shank, is typically manufactured as one piece using an ablation manufacturing process. The ablation manufacturing of trial implants from solid material is known to be costly in terms of manufacturing time and manufacturing manpower, and is not very resource efficient.

[0003] Such trial implants are known, for example, from DE 112021001452 (T5) or EP 1648351 (B1).

[0004] Also known from DE 10 2008030260 A1 is a modular trial implant system, according to which the trial implant system is of modular design, in which at least one trial implant comprises at least one first trial implant part and at least one second trial implant part, the at least one first trial implant part and the at least one second trial implant part being capable of being connected to one another in different connection positions relative to one another. Summary of the Invention

[0005] It is therefore an object of the present invention to further develop a trial implant of the above-mentioned type in a useful manner, in particular in such a way that the trial implant can be more quickly and easily adapted to an individual and can be produced more cost-effectively.

[0006] This problem is solved according to the invention by a trial implant having the features of claim 1, according to which a trial implant, in particular for spinal surgery, total knee or hip endoprostheses or shoulder prostheses, is provided, which has at least one head, at least one reinforcing core and at least one stem, the head being manufactured by 3D printing and the head and the stem being made from plastic.

[0007] The present invention is based on the basic idea that an easily fabricable trial implant is provided, consisting of only the elements head, stem and reinforcing core, where at least the head of the trial implant, which is inserted into the intervertebral space to determine the appropriate cage, is manufactured by 3D printing. 3D printing of the head allows for a cost-effective and rapid production of personalized trial implants, where the individual anatomical conditions of the affected vertebral body can be easily taken into account. The head can thus be personalized using 3D printing, which means that the dimensions of the head can be adapted to the patient's individual situation. The trial implant can be available in standardized sizes such as "small" (S), "medium" (M) or "large" (L) or can be made directly using rapid prototyping, based on the evaluation of a prior imaging procedure. The reinforcing core of the trial implant is completely located in the head-shank composite, ensuring at least sufficient bending and torsional stiffness of the trial implant. The head preferably has an elongated stepped portion for connecting with the stem and receiving the reinforcing core. This multi-part design also allows the shank and the reinforcing core to be combined with various heads. The shank may also be manufactured using 3D printing or conventional methods such as lathe, injection molding, etc. The material of the head and shank may be polypropylene (PP) if the trial implant is a single use, or polyphenylsulfone (PPSU) if the trial implant is desirably a multiple use, for the latter use polyetheretherketone (PEEK), polyetherketoneketone (PEKK), or another polyetherketone are also contemplated.

[0008] In one possible exemplary embodiment, the reinforcing core consists of a reinforced and / or composite material. This means that the choice of material for the reinforcing core can already achieve a favorable stiffness for the reinforcing core. The reinforcement, for example by fibers in the material, can also have an orientation, such as a longitudinal orientation, so that the reinforcement is more pronounced in certain directions, such as the longitudinal direction of the reinforcing core, than in other directions.

[0009] Possible reinforcing core materials can be metallic materials such as titanium alloys or stainless steel, but also carbon fiber reinforced plastics (CFRP) such as carbon fiber reinforced polyetheretherketone (CF / PEEK) can be used. Composite materials such as metal matrix composites are also contemplated.

[0010] In another possible exemplary embodiment, the material of the reinforcing core is at least partially made of CFRP and / or at least partially made of metal, which allows a good to very good stiffness, which is particularly suitable and adapted for use as a spinal implant, even with low material usage and small installation space.

[0011] In another possible exemplary embodiment, a recess is provided in both the head and the shank so that the reinforcing core is fully housed by both the head and the shank when the trial implant is fitted, which prevents the reinforcing core from coming into direct contact with, for example, patient tissue, and both the head and the shank can comprise or consist of a biocompatible material, at least on their outer (entire) or surfaces in contact with tissue, without, for example, a textile reinforcement.

[0012] The head and the shank can be pressed against the reinforcing core through the recesses, which are preferably provided in their cross-sections that are offset, and the combined longitudinal extent of the recesses in the head and the shank corresponds to the longitudinal extent of the reinforcing core, so that the reinforcing core is accommodated without play in the trial implant when the latter is fitted, i.e. when the head and the shank are connected.

[0013] Both the head recess and the shank recess can have at least a small cross-sectional taper with respect to their longitudinal extension, thereby securing the head and shank against slipping off the reinforcing core regardless of their actual connection.

[0014] In another possible exemplary embodiment, when worn, the head and shank completely house and cover the reinforcing core, thereby completely concealing the reinforcing core.

[0015] In the assembled state, the reinforcing core is disposed entirely within the head and shaft composite such that the reinforcing core does not contact the patient's tissue.

[0016] In another possible exemplary embodiment, the head and the shank are joined to each other by a gluing and / or bonding process.

[0017] In addition to the possibility of gluing the head and the shank to one another at their contact surfaces after insertion of the reinforcing core or after being placed on the reinforcing core, it is also conceivable to join the two parts by plastic welding. Furthermore, it is also conceivable that either the head or the shank has a stepped sleeve in the connecting area, i.e. a sleeve having a smaller circumference than the stepped part of the head or the shank, which sleeve is dimensioned in such a way that it is pressed into the opposite recess between the reinforcing core and the head or the shank when the head and the shank are pressed together along the reinforcing core.

[0018] In a further possible exemplary embodiment, the reinforcing core has a geometry that prevents rotation relative to the head and / or shank.

[0019] A polygonal shape, such as a triangular or square shape, about the periphery of the reinforcing core or the periphery of the recesses in the head and shaft prevents the head and shaft from twisting relative to each other after being pressed onto the reinforcing core, allowing the trial implant to be aligned without interference within the intervertebral space.

[0020] It is also contemplated that one or more ridges, protrusions or the like may be provided.

[0021] In a further possible exemplary embodiment, at least one of the elements of the head and / or the reinforcing core and / or the stem contains a contrast agent. This contrast agent allows the corresponding element to be better visualized in an imaging procedure, such as X-ray diagnosis, magnetic resonance imaging or ultrasound examination, thereby allowing the treating surgeon to optimally align the trial implant in the affected intervertebral space and to determine the necessary dimensions of the cage to be used. The elements with the contrast agent can also be better visualized for use in other surgical areas, for example when using this trial implant as a total knee or hip endoprosthesis or shoulder prosthesis. The contrast agent is confined within the corresponding element.

[0022] In a further possible exemplary embodiment, the contrast medium consists at least partially of barium sulfate, a non-toxic barium compound which, due to its opacity to X-rays, is preferably used as an X-ray positive contrast agent in X-ray diagnostics.

[0023] In another possible exemplary embodiment, the trial implant has a color coding, which allows the dimensions of the trial implant or other characteristics, such as the material of the trial implant or the hardness of the trial implant, to be quickly visually determined during surgery.

[0024] It is also conceivable that the head and the stem have different color coding. Thus, the color coding of the head can indicate its height, which is to be understood as its extension from vertebral body to vertebral body, while the color coding of the stem can indicate its length. Similarly, color coding can be assigned to different dimensions and / or geometries of the head, for example for total knee or hip endoprostheses or for shoulder prostheses.

[0025] The embodiments of the present invention will now be described below with reference to the drawings. They are not necessarily intended to show the embodiments in actual scale, and when useful for the explanation, the drawings are shown in a schematic and / or slightly distorted form. For additions to the teachings that can be directly recognized from the drawings, reference is made to the relevant state of the art. It should be noted that various modifications and changes can be made in the form and details of the embodiments without departing from the general idea of ​​the present invention. The features of the present invention disclosed in the detailed description, the drawings, and the claims may be essential for the further development of the present invention, individually or in any combination. In addition, any combination of at least two of the features disclosed in the detailed description, the drawings, and / or the claims falls within the scope of the present invention. The general idea of ​​the present invention is not limited to the exact form or details of the preferred embodiments shown and described below, nor to the subject matter that would be limited compared to the subject matter claimed in the claims. In the case of the stated design ranges, values ​​that are within the stated limits shall also be disclosed as limit values, and may be used and claimed as necessary. For the sake of simplicity, in the following, the same reference signs are used for identical or similar parts or parts with identical or similar functions.

[0026] Further advantages, features and details of the present invention will become apparent from the following description of the preferred embodiments and the drawings. [Brief description of the drawings]

[0027] [Figure 1] 1A-1D show an exemplary embodiment of a trial implant according to the present invention in a pre-assembled state. [Diagram 2] FIG. 2 shows the exemplary embodiment of a trial implant according to the invention from FIG. 1 in an assembled state. [Diagram 3] 13A-13D show a further exemplary embodiment of a trial implant according to the present invention in a pre-assembled state. [Figure 4] FIG. 4 is a view of the exemplary embodiment from FIG. 3 in a further pre-assembled state. [Diagram 5] FIG. 4 is a view of the exemplary embodiment from FIG. 3 in an assembled state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] FIG. 1 illustrates an exemplary embodiment of a trial implant 10 for spinal surgery according to the present invention in a pre-assembled state.

[0029] The trial implant 10 includes at least one head 12 , at least one reinforcing core 16 , and at least one stem 18 .

[0030] The head 12 includes a stepped portion 14 and a first recess 20a.

[0031] The stepped portion 14 and shank portion 18 of the head 12 have a circular cross-section (ie, the cross-section is perpendicular to the longitudinal axis of the implant).

[0032] The outer periphery of the head 12 is rounded.

[0033] The shaft portion 18 includes a second recess 20 b and a connecting portion 22 .

[0034] The recesses 20a, 20b are located entirely inside the head 12 or shank 18, so that only the input side is shown in FIG.

[0035] The reinforcing core 16 has a square shape, specifically, a cross section perpendicular to the longitudinal axis of the reinforcing core 16 is square.

[0036] The circumferential shape of the recesses 20 a , 20 b corresponds to the circumferential shape of the reinforcing core 16 .

[0037] The common length of the recesses 20 a , 20 b in the head 12 and shank 18 corresponds to the longitudinal extension of the reinforcing core 16 .

[0038] As a result, in the assembled condition, the reinforcing core 16 is completely received by and covered by the head 12 and shank 18 as shown in FIG.

[0039] The square shape of the reinforcing core 16 prevents the head 12 and shank 18 from rotating about their longitudinal axes, and thus relative to each other.

[0040] At least the head 12 is personalized using 3D printing, i.e. adapted to the conditions of the affected intervertebral space of the patient to be treated.

[0041] The shaft 18 may also be manufactured using 3D printing, but it is also contemplated that it is manufactured from solid material using a machining manufacturing process such as a lathe.

[0042] The head 12 and shank 18 are made from plastic.

[0043] The rounded shape of the stepped portion 14 and shaft portion 18 of the head 12 as well as the rounded periphery of the head 12 ensure that tissue and / or vertebral bodies are not scratched or damaged during insertion and removal of the trial implant 10.

[0044] The head 12 is used to measure the patient's intervertebral space for sizing the cage to be inserted. The stem 18 allows for insertion, positioning, and removal.

[0045] Additional instruments for holding and / or guiding the trial implant 10 may be placed or attached to the connection portion 22 of the stem 18 .

[0046] The head 12 and shank 18 can be made of the same or different materials, which can be polypropylene (PP) if the trial implant 10 is a single use, or polyphenylsulfone (PPSU) if the trial implant 10 is a multiple use, in which case various polyetherketones are contemplated.

[0047] Metallic materials such as titanium alloys and stainless steel as well as carbon fiber reinforced plastics (CFRP) can be used for the reinforcing core 16, as well as composite materials such as metal matrix composites.

[0048] In FIG. 2, when the trial implant is installed, the stepped portion 14 and the shank portion 18 of the head 12 are coupled to each other.

[0049] The contact surfaces of the stepped portion 14 and the shank portion 18 may be glued together, however, it is possible for the stepped portion 14 and the shank portion 18 to be joined together by a plastic weld.

[0050] Both the head 12 and / or the stem 18 contain a contrast agent, in this case barium sulfate. The contrast agent allows the corresponding elements to be better visualized in imaging procedures such as X-ray diagnostics, magnetic resonance imaging or ultrasound examination, thereby enabling the treating surgeon to optimally align the trial implant in the affected intervertebral space and to determine the necessary dimensions of the cage to be inserted. The contrast agent is suitably mixed into the material of the head 12 and the stem 18, respectively, during manufacture. This is particularly easy since the head 12 and possibly also the stem 18 are manufactured using 3D printing.

[0051] The trial implants also have a color coding, here the head of the "large" version is white. Other sizes can be visualized in further colors, such as red for the medium size and blue for the small size. In principle it is possible to define the color coding and the associated sizes as required. The color coding of the trial implants can also be used for a quick visual recording of the trial implant dimensions or other properties such as the trial implant material or the trial implant hardness during the procedure.

[0052] It is also contemplated that the head and shank may each have a different color coding, such that the color coding of the head may indicate its height, which is to be understood as its extension from vertebral body to vertebral body, while the color coding of the shank may indicate its length.

[0053] FIG. 3 shows an exemplary embodiment of a trial implant 10 for a total knee endoprosthesis according to the present invention in a pre-assembled state.

[0054] The trial implant 10 is essentially similar to the exemplary embodiment described above with reference to Figures 1 and 2. Therefore, only the differences will be described in more detail below.

[0055] Compared to the exemplary embodiment described above with reference to FIG. 1, the shape of the head 12 is adapted for use as a total knee endoprosthesis.

[0056] In this exemplary embodiment, the trial implant 10 again includes at least one head 12 , at least one reinforcing core 16 , and at least one stem 18 .

[0057] The head 12 has a stepped portion 14 .

[0058] In FIG. 3 as well, the recesses 20a, 20b of the head 12 or shank 18 are disposed entirely inside the head 12 or shank 18, so that only the input side is shown.

[0059] 4, the reinforcing core 16 is not yet fully received by the head 12 and shank 18. Instead, a gap can be seen between the head 12 and shank 18.

[0060] However, in the assembled condition shown in FIG. 5, the reinforcing core 16 is completely contained by the head 12 and the shank 18 , with the shank 18 being in direct contact with the head 12 .

[0061] In the exemplary embodiment of Figures 3-5, again at least the head 12 is personalized using 3D printing, i.e. adapted to the condition of the affected part of the patient's body to be treated.

[0062] The shaft 18 may also be manufactured using 3D printing, but it is also contemplated that it may be manufactured from a solid material using a machining manufacturing process such as a lathe.

[0063] The head 12 and shank 18 are made from plastic.

[0064] In particular, head 12 is used to measure spaces within the patient's anatomy for sizing the implant to be inserted. Shank 18 allows for insertion, positioning, and removal.

[0065] Metallic materials such as titanium, titanium alloys, or stainless steel as well as carbon fiber reinforced plastics (CFRP) can be used for the reinforcing core 16, as well as composite materials such as metal matrix composites. [Explanation of symbols]

[0066] 10 Trial Implants for Spinal Surgery 12 Head 14 Stepped part of head 16 Reinforcement core 18 Shank 20a, 20b Recess 22 Connection

Claims

1. A trial implant (10) especially for spinal surgery, total knee or hip endoprostheses or shoulder prostheses, having at least one head (12), at least one reinforcement core (16) and at least one shaft (18), wherein said head (12) is manufactured by 3D printing and said head (12) and said shaft (18) are made of plastic.

2. The trial implant (10) according to claim 1, wherein said reinforcement core (16) consists of a reinforced material and / or a composite material.

3. The trial implant (10) according to claim 2, wherein the material of said reinforcement core (16) consists at least partly of CFRP and / or at least partly of metal.

4. The trial implant (10) according to any one of claims 1 to 3, wherein recesses (20a, 20b) are provided in both said head (12) and said shaft (18) such that when the trial implant (10) is implanted, said reinforcement core (16) is completely received by both said head (12) and said shaft (18).

5. The trial implant (10) according to claim 4, wherein when assembled, the head (12) and the shaft (18) completely cover the reinforcement core (16), thereby completely hiding the reinforcement core (16).

6. The trial implant (10) according to any one of claims 1 to 3, wherein the head (12) and the shaft (18) are joined to each other by an adhesive treatment and / or a bonding treatment.

7. The trial implant (10) according to any one of claims 1 to 3, wherein said reinforcement core (16) has a geometry that prevents rotation relative to said head (12) and / or said shaft (18).

8. The trial implant (10) according to any one of claims 1 to 3, wherein at least one of the elements of said head (12) and / or reinforcement core (16) and / or shaft (18) contains a contrast agent.

9. The trial implant (10) according to any one of claims 1 to 3, wherein said contrast agent consists at least partly of barium sulfate.

10. The trial implant (10) according to any one of claims 1 to 3, wherein the trial implant (10) has color coding.

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