Device and method for producing spacers

Patent metadata

Field	Value
Publication number	US-11865006-B2
Application number	US-202117382958-A
Country	US
Kind code	B2
Filing date	Jul 22, 2021
Priority date	Aug 17, 2020
Publication date	Jan 9, 2024
Grant date	Jan 9, 2024

Abstract

The invention relates to a device for producing a spacer havinga stem mold (1) which has an inner space (2), wherein the inner space (2) is accessible via a proximal opening (3) and wherein the stem mold (1) has a proximal wall (4) which peripherally delimits the proximal opening (3) of the stem mold (1),a head mold (5) which has in the interior thereof a hollow space (6), wherein the hollow space (6) has a spherical surface-shaped inner surface (7) and is accessible via a distal opening (8), wherein the head mold (5) has a distal wall (9) which peripherally delimits the distal opening (8) of the head mold (5),a metal core (10) which has a stem part (12), a head part (14) and a flange (16), wherein the flange (16) projects out from the metal core (10), is arranged between the stem part (12) and the head part (14) and has a proximal surface (18) and a distal surface (20),wherein the stem mold (1) and the stem part (12) are shaped such that the stem part (12) is arranged in the inner space (2), when the proximal wall (4) is resting against the distal surface (20), and wherein the head mold (5) and the head part (14) are shaped such that the head part (14) is arranged in the hollow space (6), when the distal wall (9) is resting against the proximal surface (18).The invention also relates to a set with such a device and to a method for producing spacers with such a device.

First claim

The invention claimed is:

1. A device for producing a spacer by curing bone cement paste, wherein the spacer is provided in the medical field for temporarily replacing a joint or part of a joint comprising an articulating surface of a head of the joint, the device having:
a stem mold for shaping a stem of the spacer from bone cement paste, wherein the stem mold has in the interior thereof an inner space, wherein the inner space is accessible via a proximal opening on a proximal side of the stem mold and wherein the stem mold has a proximal wall which peripherally delimits the proximal opening of the stem mold,
a head mold for shaping a head and a neck of the spacer from bone cement paste, wherein the head mold has in the interior thereof a hollow space, wherein the hollow space has a spherical surface-shaped inner surface for shaping a sliding surface of the head of the spacer and the hollow space is accessible via a distal opening on a distal side of the head mold, wherein the head mold has a distal wall which peripherally delimits the distal opening of the head mold,
a metal core, wherein the metal core has a stem part, a head part and a flange, wherein the flange projects out from the metal core, wherein the flange is arranged between the stem part and the head part and wherein the flange has a proximal surface and a distal surface,
wherein the stem mold and the stem part of the metal core are shaped such that the stem part is arranged in the inner space of the stem mold, when the proximal wall of the stem mold is resting against the distal surface of the flange,
wherein the head mold and the head part of the metal core are shaped such that the head part is arranged in the hollow space of the head mold, when the distal wall of the head mold is resting against the proximal surface of the flange, and
wherein the head mold has a neck mold for shaping a neck of the spacer, which neck connects the head and the stem, from bone cement paste, wherein the neck mold is tubular or hollow-cylindrical, wherein the distal opening and the distal wall of the head mold are both parts of the neck mold and the spherical surface-shaped inner surface of the hollow space is not part of the neck mold,
wherein centering means are arranged on the head part to facilitate positioning and orientation of the head part in the head mold when the head part is pushed through the distal opening into the head mold,
wherein the centering means rest against the inner wall of the hollow space of the neck mold of the head mold when the head part is completely pushed into the head mold,
and, the head part is shaped on the proximal side thereof with a cone intended to facilitate its being pushed into the bone cement paste.

2. The device according to claim 1 , characterized in that the metal core consists of the stem part, the head part and the flange and/or the metal core is one-part.

3. The device according to claim 1 , characterized in that the stem mold and/or the head mold consists or consist of a plastics material, or of at least one plastics film or of an injection-molded plastics material.

4. The device according to claim 1 , characterized in that the stem part is spaced in the inner space of the stem mold from inner walls of the stem mold which delimit the inner space, when the proximal wall of the stem mold is resting against the distal surface of the flange, or is resting flush against the distal surface of the flange.

5. The device according to claim 1 , characterized in that the head part is spaced in the hollow space of the head mold from inner walls of the head mold which delimit the hollow space, when the distal wall of the head mold is resting against the proximal surface of the flange, or is resting flush against the proximal surface of the flange.

6. The device according to claim 1 , characterized in that the head mold and the head part of the metal core are shaped such that the head part protrudes beyond the neck mold into the hollow space of the head mold, when the distal wall is resting against the proximal surface of the flange.

7. The device according to claim 1 , characterized in that the length of the neck mold is adjustable by shortening the neck mold, wherein, predetermined cutting or tearing points are arranged on the neck mold and/or a scale is arranged externally on the neck mold.

8. The device according to claim 1 , characterized in that the proximal surface of the flange limits displacement of the metal core in the head mold, or in the neck mold, and/or the distal surface of the flange limits displacement of the metal core in the stem mold.

9. The device according to claim 1 , characterized in that centering means are arranged on the head part of the metal core, wherein the centering means project out from the surface of the head part, wherein the centering means space inner walls of the head mold from the head part, when the head part of the metal core is pushed into the hollow space of the head mold, or the neck mold of the head mold is spaced from the head part, when the head part of the metal core is pushed into the hollow space of the head mold.

10. The device according to claim 1 , characterized in that spacing pieces are arranged on the stem part of the metal core, wherein the spacing pieces project out from the surface of the stem part, wherein the spacing pieces space inner walls of the stem mold from the stem part of the metal core, when the stem part of the metal core is pushed into the inner space of the stem mold.

11. The device according to claim 1 , characterized in that the outer circumference of the flange is larger than at least one of the proximal opening of the stem mold and the distal opening of the head mold.

12. The device according to claim 1 , characterized in that at least one vent opening is arranged in at least one of the stem mold and the head mold, wherein the at least one vent opening gas-permeably connects at least one of the inner space of the stem mold and the hollow space of the head mold with the surroundings of the device, wherein the at least one vent opening is permeable to gases and impermeable to bone cement paste.

13. The device according claim 1 , characterized in that the device is intended to be used in a set with a cement powder packaged in at least one microbe-proof cement container and a monomer liquid packaged in at least one microbe-proof and liquid-tight monomer liquid container.

14. The device according to claim 13 , characterized in that the device is intended to be used in a set with at least one bone cement cartridge for mixing the cement powder with the monomer liquid and for delivering mixed bone cement paste from the bone cement cartridge, wherein the at least one bone cement cartridge has the at least one microbe-proof cement container and contains the at least one microbe-proof and liquid-tight monomer liquid container, wherein the at least one microbe-proof cement container and the at least one microbe-proof and liquid-tight monomer liquid container are arranged in mutually separate regions.

15. A set for producing different spacers by curing bone cement paste, wherein the spacers are provided in the medical field for temporarily replacing a joint or part of a joint comprising an articulating surface of a head of the joint, the set having at least one device according to claim 1 , wherein the set has at least two head molds with different diameters of the spherical surface-shaped inner surfaces and/or at least two stem molds with hollow spaces of different lengths in the distal direction or different internal diameters of the hollow spaces.

16. The set a

Assignees

• Heraeus Medical Gmbh

Inventors

• Vogt Sebastian
• Kluge Thomas

Classifications

• A61F2/30724 Primary

  Spacers for centering an implant in a bone cavity, e.g. in a cement-receiving cavity · CPC title

• A61F2/30942 Primary

  for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques · CPC title

• A61F2/4684

  Trial or dummy prostheses · CPC title

• B29B7/90

  Fillers or reinforcements {, e.g. fibres} · CPC title

• B29C45/34

  having venting means · CPC title