Device and method for providing a bone cement dough
Patent Information
- Application Number
- AU2025235325
- Authority / Receiving Office
- AU · AU
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-03-15
- Filing Date
- 2025-03-10
- Publication Date
- 2026-09-17
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
Device and method for preparing a bone cement paste The invention relates to a device for preparing a bone cement paste from two starting components, the device comprising a mixing unit comprising an interior space in which a bone cement powder as a first starting component is or can be stored, a reservoir comprising a reservoir container in which at least one fluidically closed monomer liquid container filled with a monomer liquid as a second starting component is or can be stored, a transfer unit comprising a hollow cylinder and a conveying piston that is axially displaceable in the hollow cylinder, wherein the mixing unit and the reservoir are or can be fluidically connected to each other via the hollow cylinder, wherein the monomer liquid container in the device is to be opened in such a way that the monomer liquid can flow from the reservoir into the hollow cylinder via a passage and can be conveyed from the hollow cylinder into the interior space by an axial displacement of the conveying piston in the hollow cylinder. The invention also relates to a method for preparing a bone cement paste from two starting components by means of such a device. Background of the invention Significant efforts are being made to identify devices and methods for preparing bone cement that enable bone cement paste to be prepared easily, reliably, and quickly. One important aspect when preparing bone cement paste is to avoid air inclusions, such as gas bubbles, in the bone cement. To avoid these, a plurality of vacuum cementing systems have been described, of which the following are mentioned by way of example: US 6,033,105 A, US 5,624,184 A, US 4,671,263 A, US 4,973,168 A, US 5,100,241 A, WO 99 / 67015 A1, EP 1020167 A2, US 5,586,821 A, EP 1016452 A2, DE 3640279 A1, WO 94 / 26403 A1, EP 1005901 A2, EP 1886647 A1, US 5,344,232 A. There is a desire in the market to simplify the preparation of bone cement paste. One further development consists in developing cementing systems in which the two starting components are stored in separate areas of the mixing systems and are not mixed together in the cementing system until just before the cementing application. Such closed, so-called full-prepacked systems are mentioned, for example, in the following documents: EP 0 692 229 A1, DE 10 2009 031 178 B3, US 5,997,544 A, US 6,709,149 B1, DE 698 12 726 T2, EP 0 796 653 A2, US 5,588,745 A. In the aforementioned full-prepacked systems, a monomer liquid is mixed with a bone cement powder by mechanical mixing, for example by means of a mixing rod. Patent application EP 3 093 067 A1 describes a further device for preparing a bone cement paste. The device comprises a mixing unit, in which a bone cement powder as a first starting component is stored, and a reservoir, in which a monomer liquid as a second starting component is stored in an ampule. The mixing unit is fluidically connected to the reservoir via a hollow cylinder of a transfer unit. Once the ampule has been fluidically opened by the reservoir being snapped off, the monomer liquid can flow into the hollow cylinder, from where it can be conveyed into the mixing unit by an axial displacement of a conveying piston of the transfer unit in the hollow cylinder. One disadvantage of such a system is that the steps of fluidically opening and conveying the monomer liquid from the hollow cylinder into the mixing unit may take place simultaneously. The result of this is, for example, that the conveying is initiated before all the monomer liquid has flowed from the reservoir into the hollow cylinder, which leads to undesired compositions of the bone cement paste, for example due to incomplete conveying of the monomer liquid. The device is therefore prone to operator error. There is therefore a desire in the market to further simplify devices for preparing bone cement paste, and in particular a desire for safe-to-use devices that minimize operator errors. Objects One object of the present invention is to overcome, at least in part, one or more of the disadvantages found in the prior art. Specifically, the aim of the invention is to provide a device which enables easy and safe preparation of a bone cement paste. In particular, the device is intended to make it possible to convey a desired amount of a monomer liquid into a bone cement powder as safely as possible, so that a bone cement paste can be prepared with a desired mixing ratio of these two starting components. In particular, a monomer liquid container filled with the monomer liquid should be opened with as little effort as possible, while avoiding the use of additional, separate tools. In addition, the monomer liquid container should be able to be opened using as few components as possible. In addition, the monomer liquid should be made available quickly, and with as little loss as possible, for preparing the bone cement paste. The conveying of the monomer liquid into a bone cement powder in order to prepare the bone cement paste should be able to be done using the lowest possible amount of force. The device should be able to be operated with the simplest possible work steps and with the greatest possible user safety. Another object of the invention is to provide a method by which bone cement can be prepared from two starting components, by means of which method at least some of the above-described objects are achieved, at least in part. Preferred embodiments of the invention A contribution to the at least partial fulfillment of at least one of the aforementioned objects is made by the features of the independent claims. The dependent claims provide preferred embodiments that contribute to the at least partial fulfillment of at least one of the objects. A first embodiment of the invention is a device for preparing a bone cement paste from two starting components, the device comprising a mixing unit comprising an interior space in which a bone cement powder as a first starting component is or can be stored, preferably is stored, a reservoir comprising a reservoir container in which at least one fluidically closed monomer liquid container filled with a monomer liquid as a second starting component is or can be stored, preferably is stored, a transfer unit comprising a hollow cylinder and a conveying piston that is axially displaceable in the hollow cylinder, wherein the mixing unit and the reservoir are or can be fluidically connected to each other via the hollow cylinder, wherein the monomer liquid container in the device is to be opened in such a way that the monomer liquid can flow from the reservoir into the hollow cylinder via a passage and can be conveyed from the hollow cylinder into the interior space by an axial displacement of the conveying piston in the hollow cylinder, characterized in that in a first configuration of the device the conveying piston is connected to an opening means such that an axial displacement of the conveying piston from a first position to a second position pushes the opening means against the monomer liquid container such that the monomer liquid container can be fluidically opened by the opening means and the monomer liquid can flow from the reservoir into the hollow cylinder via the passage, and in that in a second configuration of the device the conveying piston is separated from the opening means such that the monomer liquid can be conveyed from the hollow cylinder into the interior space by a further axial displacement of the conveying piston from the second position toward a third position. In one embodiment of the device, in the first configuration the conveying piston is displaceable only between the first position and the second position. This embodiment is a second embodiment of the invention, which is preferably dependent on the first embodiment of the invention. In one embodiment of the device, in the first configuration the opening means bears against a stop in the second position of the conveying piston such that further axial displacement of the conveying piston from the second position toward the third position is prevented. This embodiment is a third embodiment of the invention, which is preferably dependent on the second embodiment of the invention. In one embodiment of the device, the opening means is a wedge. This embodiment is a fourth embodiment of the invention, which is preferably dependent on any of the preceding embodiments of the invention. In one embodiment of the device, the wedge comprises at least one through-opening such that the monomer liquid can flow from the reservoir into the hollow cylinder through the through-opening and the passage. This embodiment is a fifth embodiment of the invention, which is preferably dependent on the fourth embodiment of the invention. In one embodiment of the device, wherein the monomer liquid container is an ampule, preferably a glass ampule, and is stored in the reservoir container, wherein the opening means is arranged axially above an ampule head of the ampule such that, when the conveying piston is displaced from the first position to the second position in the first configuration of the device, the opening means can be pressed or pushed against the ampule head and thus the ampule can be fluidically opened. This embodiment is a sixth embodiment of the device, which is preferably dependent on any of the preceding embodiments of the invention. In one embodiment of the device, the conveying piston and the opening means are connected to each other via a driver in the first configuration. This embodiment is a seventh embodiment of the device, which is preferably dependent on any of the preceding embodiments of the invention. In one embodiment of the device, the driver is separated from the opening means when the device is moved from the first configuration to the second configuration. This embodiment is an eighth embodiment of the device, which is preferably dependent on the seventh embodiment of the invention. In one embodiment of the device, the preferably reversible movement of the device from the first configuration to the second configuration can be achieved by rotating the conveying piston about a conveying piston longitudinal axis. This embodiment is a ninth embodiment of the invention, which is preferably dependent on the eighth embodiment of the invention. In one embodiment of the device, the driver is arranged on a ring around the conveying piston such that the movement of the device from the first configuration to the second configuration can be achieved by rotating the ring around the conveying piston. This embodiment is a tenth embodiment of the invention, which is preferably dependent on the eighth embodiment of the invention. In one embodiment of the device, the device comprises a transport lock which prevents unintentional displacement of the opening means. This embodiment is an eleventh embodiment of the invention, which is preferably dependent on any of the preceding embodiments of the invention. In one embodiment of the device, the conveying piston comprises at least one detachable, preferably reversibly detachable, control element which limits the displacement of the conveying piston between the second position and the third position to an intermediate position, in particular to an intermediate position spatially between the second position and the third position. This embodiment is a twelfth embodiment of the invention, which is preferably dependent on any of the preceding embodiments of the invention. In one embodiment of the device, the conveying piston fluidically closes the passage when axially displaced from the second position toward the third position. This embodiment is a thirteenth embodiment of the invention, which is preferably dependent on any of the preceding embodiments of the invention. A fourteenth embodiment of the invention is a method for preparing a bone cement paste from two starting components by means of a device according to any of embodiments one to thirteen of the invention, wherein a bone cement powder as a first starting component is stored in the interior space and a fluidically closed monomer liquid container filled with a monomer liquid as a second starting component is stored in the reservoir container, the method comprising the method steps of: a. providing the device in the first configuration; b. axially displacing the conveying piston from the first position to the second position, thereby fluidically opening the monomer liquid container; c. allowing the monomer liquid to flow from the reservoir into the hollow cylinder; d. moving the device from the first configuration to the second configuration; e. axially displacing the conveying piston from the second position toward the third position, thereby conveying the monomer liquid from the hollow cylinder into the interior space; f. mixing the bone cement powder and the monomer liquid in the mixing unit to prepare the bone cement paste. In one embodiment of the method, the movement of the device from the first configuration to the second configuration takes place by way of a rotational movement. This embodiment is a fifteenth embodiment of the invention, which is preferably dependent on the fourteenth embodiment of the invention. General matters In the present description, specified ranges also include the values stated as limits. Therefore, a specification of the type “in the range from X to Y” regarding a parameter A means that A can assume the values X, Y, and values between X and Y. Ranges that are limited at one end, of the type “up to Y” for a parameter A, accordingly mean a value Y and less than Y. Some of the features described are associated with the term “substantially.” The term “substantially” is to be understood in such a way that, under real conditions and manufacturing techniques, a mathematically exact interpretation of terms such as “superimposition,” “perpendicular,” “diameter,” or “parallelism” can never be given exactly, but only within certain manufacturing error tolerances. For example, “substantially perpendicular axes” enclose an angle of 85 degrees to 95 degrees with each other, and “substantially equal volumes” comprise a deviation of up to 5 vol.%. A “device made substantially of plastic” comprises, for example, a plastic content of >95 to <100 wt.%. A “substantially complete filling of a volume B” comprises, for example, a filling of >95 to <100 vol.% of the total volume of B. The terms “proximal” and “distal” merely serve to designate the spatially opposite ends of the device or other structural units of the device and do not enable any conclusions to be drawn about the orientation in relation to a human body, for example a user of the device. “Distal to ...” and “proximal to ...” or similar formulations merely express the spatial arrangement of two structural units of the device in relation to each other. Detailed description A first subject matter of the invention relates to a device for preparing a bone cement paste from two starting components, the device comprising a mixing unit comprising an interior space in which a bone cement powder as a first starting component is or can be stored, a reservoir comprising a reservoir container in which at least one fluidically closed monomer liquid container filled with a monomer liquid as a second starting component is or can be stored, a transfer unit comprising a hollow cylinder and a conveying piston that is axially displaceable in the hollow cylinder, wherein the mixing unit and the reservoir are or can be fluidically connected to each other via the hollow cylinder, wherein the monomer liquid container in the device is to be opened in such a way that the monomer liquid can flow from the reservoir into the hollow cylinder via a passage and can be conveyed from the hollow cylinder into the interior space by an axial displacement of the conveying piston in the hollow cylinder, characterized in that in a first configuration of the device the conveying piston is connected to an opening means such that an axial displacement of the conveying piston from a first position to a second position pushes the opening means against the monomer liquid container such that the monomer liquid container can be fluidically opened by the opening means and the monomer liquid can flow from the reservoir into the hollow cylinder via the passage, and in that in a second configuration of the device the conveying piston is separated from the opening means such that the monomer liquid can be conveyed from the hollow cylinder into the interior space by a further axial displacement of the conveying piston from the second position toward a third position. Preferably, both the bone cement powder and at least one monomer liquid container are stored in the device. The device is used to mix a bone cement paste from a bone cement powder and a monomer liquid, wherein, prior to the mixing, the bone cement powder can be or preferably is stored in a mixing unit of the device and the monomer liquid can be or preferably is stored in a reservoir of the device. Preferably, the monomer liquid is located in the reservoir, in particular in a reservoir container of the reservoir, inside one or more monomer liquid containers. The reservoir container is designed to store this or these monomer liquid container(s) in a safe and sterile manner. A monomer liquid container is a vessel for the monomer liquid, in which the latter can be stored in a safe and in particular sterile manner until it is used. Various monomer liquid containers are known to a person skilled in the art. For example, the monomer liquid container may be a pouch. Preferred pouches are multilayer composite films with an EVOH (ethylene vinyl alcohol) barrier layer, optionally comprising a metal coating, in particular comprising an aluminum coating. Preferably, the monomer liquid container is an ampule, preferably a glass ampule. Preference is given to ampules since these can be opened with greater control and it is easier for all the monomer liquid to flow out of fluidically open ampules. The mixing unit is used to mix the bone cement paste from the bone cement powder and the monomer liquid after the monomer liquid has been conveyed into the mixing unit, in particular after the monomer liquid has been conveyed into an interior space of the mixing unit in which preferably the bone cement powder is stored. The mixing unit preferably comprises a hollow-cylindrical cartridge. A hollow-cylindrical cartridge is to be understood as a tubular container which comprises an interior space and a cartridge wall surrounding the interior space. The cross-section of the cartridge may take any desired shape. For reasons of easy manufacture and more reliable use of the device, the cross-section thereof, and preferably also the cross-section of the interior space, is circular. This enables easy handling for the user and, due to an absence of edges, reduces the risk of moving parts becoming wedged within the device. According to the invention, the cartridge may be made of a wide variety of materials or combinations of materials. For example, the device may be made of a polymer. The polymer is preferably a transparent polymer, since in this way the user can visually monitor the proper functioning of the device during use. In order to mix the bone cement paste from the two starting materials in the mixing unit, preferably a mixing element that is reversibly axially displaceable in the interior space is arranged in the interior space. A reversible back-and-forth movement of the mixing element in the interior space leads to the most homogeneous possible mixing of the bone cement powder and the monomer liquid to prepare the bone cement paste. By way of example, the mixing element may be a mixing rod, with rotor-like mixing blades being arranged at an end of the mixing rod arranged in the interior space. Preferably, the mixing rod is mounted in the interior space in such a way as to also be rotatable about its longitudinal axis, so that such rotation of the mixing blades can aid the process of mixing the two starting components. The mixing unit preferably comprises a discharge opening, from which the bone cement paste prepared in the mixing unit can be discharged. Preferably, the mixing unit is fluidically connected to the transfer unit via the discharge opening, preferably via a connecting line, such as a hose. To discharge the bone cement paste from the mixing unit, it is therefore preferred to detach the mixing unit from the rest of the device, in particular the transfer unit and also the hose between the mixing unit and the transfer unit, so that the bone cement paste can be discharged through the discharge opening. To discharge the bone cement paste, the mixing unit preferably comprises a conveying piston that is axially movable in the interior space. The transfer unit is fluidically arranged between the reservoir and the mixing unit. The transfer unit comprises a hollow cylinder and a conveying piston that is axially displaceable in the hollow cylinder. The hollow cylinder is fluidically connected to the reservoir, in particular the reservoir container, via a passage, so that the monomer liquid from a fluidically opened monomer liquid container in the reservoir can flow into the hollow cylinder via the passage. The hollow cylinder is designed to receive all of the monomer liquid stored in the reservoir when the device is in use. A fluidic connection also exists between the hollow cylinder and the mixing unit, so that the monomer liquid located in the hollow cylinder can be transferred into the mixing unit. Preferably, the hollow cylinder is fluidically connected to the mixing unit via a connecting line, preferably a hose. Preferably, the connecting line between the transfer unit and the mixing unit is arranged in a loop with a high apex to prevent the monomer liquid from flowing in an uncontrolled manner through the connecting line into the mixing unit, in particular the interior space. The monomer liquid located in the hollow cylinder thus preferably remains within the hollow cylinder until a user of the device actively intervenes to convey the monomer liquid into the mixing unit, in particular the interior space. To convey the monomer liquid from the hollow cylinder into the mixing unit, in particular the interior space, the transfer unit comprises a conveying piston. The conveying piston is axially displaceable in the hollow cylinder and forms with the hollow cylinder a piston-cylinder system for conveying the monomer liquid. Preferably, the connecting line is located at an axial end of the hollow cylinder, so that a displacement of the conveying piston toward the connecting line can bring about substantially complete conveying of the monomer liquid from the hollow cylinder into the mixing unit. The reservoir, in particular the reservoir container, serves to store the monomer liquid container filled with the monomer liquid, the monomer liquid container remaining fluidically closed until use. The device comprises an opening means for fluidically opening the fluidically closed monomer liquid container. The opening means is configured for the type and nature of the monomer liquid container, but is designed in such a way that pushing, or in other words “pressing,” the opening means against the monomer liquid container overcomes the structural integrity of the latter and thus fluidically opens it. To this end, the opening means preferably comprises a pointed or sharp-edged side or face which is mounted to push against the monomer liquid container. Preferably, the opening means is arranged within the reservoir such that it can be displaced into contact with the monomer liquid container. In a first configuration of the device, the conveying piston is connected to the opening means such that an axial displacement of the conveying piston from a first position, in particular from a first spatial position within the hollow cylinder, to a second position, in particular to a second spatial position within the hollow cylinder, pushes the opening means against the monomer liquid container and thus can fluidically open the latter. This means that, in the first configuration, a movement of the conveying piston is transmitted to the conveying piston. In other words, in the first configuration, the opening means can be operated via the conveying piston. Preferably, an axial displacement of the conveying piston within the hollow cylinder leads to an identical displacement of the opening means within the reservoir, preferably by the same distance. In a second configuration of the device, the conveying piston is separated from the opening means. Therefore, in contrast to the first configuration, a movement, in particular an axial displacement, of the conveying piston within the hollow cylinder does not lead to a displacement of the opening means. In the second configuration, a further axial displacement, i.e. a displacement in the same direction, of the conveying piston from the second position toward a third position, in particular toward a third spatial position within the hollow cylinder, leads to the monomer liquid located in the hollow cylinder being conveyed into the mixing unit, in particular into the interior space of the mixing unit. The device therefore has two different configurations. The first configuration serves to fluidically open the monomer liquid container and thus allow the monomer liquid to flow from the reservoir into the hollow cylinder of the transfer unit, while the second configuration serves to convey the monomer liquid from the transfer unit into the mixing unit. The two configurations of the device thus separate, functionally and temporally, due to the time delay caused by the configuration change, the two method steps in preparing the bone cement paste, which increases the user safety of the device. In particular, this reduces the risk that conveying of the monomer liquid will be initiated by the user before substantially all the monomer liquid has flowed from the reservoir into the transfer unit. One embodiment of the device is characterized in that, in the first configuration, the conveying piston is displaceable only between the first position and the second position. In this embodiment, in order to convey the monomer liquid from the transfer unit into the mixing unit, the device must be in the second configuration, which further increases the safety of use. In contrast, in the first configuration, only fluidic opening of the monomer liquid container is possible, but not conveying of the monomer liquid from the transfer unit into the mixing unit. The device may be configured in different ways such that the conveying of the monomer liquid from the transfer unit into the mixing unit is only possible in the second configuration, but not in the first configuration. One embodiment of the device is characterized in that, in the first configuration, the opening means bears against a stop in the second position of the conveying piston such that further axial displacement from the second position toward the third position is prevented. The stop prevents further displacement of the opening means. Since the opening means is connected to the conveying piston in the first configuration, the blocked opening means ensures that the conveying piston also cannot be displaced from the second position toward the third position. Since the conveying of the monomer liquid only begins when the conveying piston is displaced from the second position toward the third position, the stop ensures that conveying is not possible in the first configuration of the device. This increases the safety of use of the device since active switching from the first configuration to the second configuration is necessary in order to initiate the conveying of the monomer liquid into the mixing unit. The stop may be positioned at different points on the opening means in the second position of the conveying piston in order to block the conveying piston in the direction of the third position. By way of example, the stop may be a wall inside the reservoir, against which there butts in the second position of the conveying piston an end of the opening means that faces toward the monomer liquid container and that was used to fluidically open the latter. The stop may also be a protrusion inside or outside the reservoir, against which a protuberance on the opening means butts in the second position of the conveying piston and thus blocks the latter. This protuberance may also be arranged at an end of the opening means remote from the monomer liquid container. The opening means may be configured in different ways to fluidically open the monomer liquid container. In particular, the embodiment of the opening means depends on the type of monomer liquid container. By way of example, the opening means may be a spike, which is particularly preferred when using a pouch as the monomer liquid container. One embodiment of the device is characterized in that the opening means is a wedge. The wedge comprises at least one edge, preferably a sharp edge, at least in the direction of the monomer liquid container, in this case preferably an ampule, which facilitates opening of the monomer liquid container. One embodiment of the device is characterized in that the wedge comprises at least one through-opening, in particular a fluidic through-opening, such that the monomer liquid can flow from the reservoir into the hollow cylinder through the through-opening and the passage. Depending on the embodiment of the device, the opening means in the form of a wedge may make it more difficult for the monomer liquid to flow out of the monomer liquid container, preferably in the form of an ampule, after the monomer liquid container has been opened, since the wedge is located in the natural flow path of the monomer liquid toward the passage, and thus toward the transfer unit. In such an embodiment, the at least one through-opening ensures improved flowability of the monomer liquid. By way of example, the through-opening is formed as a hole in the wedge. In another embodiment, the through-opening divides an edge of the wedge into two edge portions, so that the monomer liquid can flow between these edge portions. One embodiment of the device is characterized in that the monomer liquid container is an ampule, preferably a glass ampule, and is stored in the reservoir container, and in that the opening means is arranged axially above an ampule head of the ampule such that, when the conveying piston is displaced from the first position to the second position in the first configuration of the device, the opening means can be pressed against the ampule head and thus the ampule can be fluidically opened. In this embodiment, the ampule and the opening means are oriented relative to each other such that, when used correctly, the opening means presses against the ampule head of the ampule and fluidically opens the ampule in the region of the ampule head, preferably at an ampule neck of the ampule. In ampules known to a person skilled in the art for monomer liquids, in particular glass ampules, an ampule body that can hold the majority of the monomer liquid is connected to the ampule head via a narrower ampule neck. The ampule neck constitutes a predetermined breaking point of the ampule, at which the latter can be fluidically opened easily and controllably. To this end, usually pressure is exerted on the ampule head, which causes it to break off at the ampule neck. In the first configuration of the device, the conveying piston and the opening means can be connected to each other in different ways such that a displacement of the conveying piston brings about a displacement of the opening means. One embodiment of the device is characterized in that the conveying piston and the opening means are connected to each other via a driver in the first configuration. A driver is a structural unit of the device that establishes a direct connection between the conveying piston and the opening means. The driver thus leads to a synchronous, parallel displacement of the conveying piston and the opening means by the same distance. In this embodiment, a change from the first configuration to the second configuration can take place in different ways. By way of example, the driver can be detached from both the conveying piston and the opening means such that the conveying piston and the opening means are no longer connected to each other. Alternatively, the driver is detached from the conveying piston, but not from the opening means. This also leads to the conveying piston and the opening means no longer being connected to each other, and a displacement of the conveying piston has no effect on the opening means. One embodiment of the device is characterized in that the driver is separated, or in other words detached, from the opening means when the device is moved from the first configuration to the second configuration. In this embodiment, the driver preferably remains connected to the conveying piston in the second configuration. Separating the driver from the opening means when changing from the first configuration to the second configuration can be achieved in different ways. By way of example, the driver may be designed to be removable from the opening means, or the driver is designed with a releasable mount which is closed in the first configuration and opened in the second configuration. One embodiment of the device is characterized in that the movement of the device from the first configuration to the second configuration can be achieved by rotating the conveying piston about a conveying piston longitudinal axis. Rotation about the conveying piston longitudinal axis thus ensures that the driver is detached from the opening means, with the driver remaining connected to the conveying piston and rotating with the conveying piston. In this embodiment, the driver is preferably in engagement with the opening means in the first configuration such that an axial displacement of the conveying piston, and thus also of the driver, is transmitted to the opening means, but this engagement is released by rotating the conveying piston, and thus also the driver. By way of example, the driver comprises a pin at an end facing toward the opening means, which pin in the first configuration of the device engages in a pin-shaped recess on the opening means and thus connects the two elements. By rotating the conveying piston, the pin slides out of the recess and the driver and the opening means are no longer connected to each other, so that the device is in the second configuration. One embodiment of the device is characterized in that the driver is arranged on a ring around the conveying piston, in particular around a conveying piston circumference of the conveying piston, such that the movement of the device from the first configuration to the second configuration can be achieved by rotating the ring around the conveying piston. This embodiment is similar to the preceding embodiment, except that, instead of rotating the conveying piston, rotating the ring causes the driver to detach from the opening means. Although the driver remains attached to the conveying piston in this embodiment as well, the driver is rotatable independently of any rotational movement of the conveying piston. The ring, via which the driver is arranged on the conveying piston, may extend around all or just part of a conveying piston circumference. By way of example, the ring may be a type of clamp which rotatably fastens the driver to the conveying piston. Regardless of the exact embodiment of the ring, it always ensures that an axial displacement of the conveying piston leads to an identical displacement of the driver. One embodiment of the device is characterized in that the device comprises a transport lock which prevents unintentional displacement of the opening means, in particular also in the first configuration of the device. The transport lock thus ensures, in particular, safe transport of the device, especially if the monomer liquid container is already located in the reservoir container. To convey the monomer liquid from the hollow cylinder into the interior space of the mixing unit, the conveying piston is displaceable from the second position toward the third position in the second configuration of the device. The conveying of the monomer liquid may begin immediately upon starting to displace the conveying piston from the second position toward the third position. The conveying of the monomer liquid may also begin only after the conveying piston has already traveled a portion of the distance between the second position and the third position. For example, if this portion, prior to the displacement of the conveying piston, is filled not with monomer liquid but instead with gas, for example air or a protective gas, such as nitrogen. This is usually due to the volume of the hollow cylinder, depending on the amount of monomer liquid used. The third position can be regarded as the position of the conveying piston that enables substantially all the monomer liquid to be conveyed out of the hollow cylinder. Displacing the conveying piston from the second position toward the third position and ultimately into the third position thus enables some, or upon reaching the third position substantially all, of the monomer liquid to be conveyed. By way of example, in order to obtain a specific mixing ratio of bone cement powder to monomer liquid, it may be desirable that not all of the monomer liquid present in the monomer liquid container is to be conveyed into the mixing unit. Under these circumstances, the conveying piston is only to be displaced a corresponding portion of the distance from the second position to the third position, but not the entire distance to the third position. One embodiment of the device is characterized in that the conveying piston comprises at least one detachable control element which limits the displacement of the conveying piston between the second position and the third position to an intermediate position. The control element thus enables a user of the device to set the position to which the conveying piston is to be able to be displaced in the second configuration, which has a direct effect on the amount of monomer liquid conveyed from the hollow cylinder into the interior space. By way of example, the control element may be set such that the conveying piston can only be pushed into the hollow cylinder as far as an intermediate position that allows half the amount of monomer liquid present in the hollow cylinder to be conveyed. The control element may be, for example, a clamp, a cuff, a chuck or a clip, which can be detachably fastened to an outside of the conveying piston and thus limits the displacement of the conveying piston toward the third position to an intermediate position. A further subject matter of the invention relates to a method for preparing a bone cement paste from two starting components by means of a device according to any of the preceding embodiments, wherein a bone cement powder as a first starting component is stored in the interior space and a fluidically closed monomer liquid container filled with a monomer liquid as a second starting component is stored in the reservoir container, the method comprising the method steps of: a. providing the device in the first configuration; b. axially displacing the conveying piston from the first position to the second position, thereby fluidically opening the monomer liquid container; c. allowing the monomer liquid to flow from the reservoir into the hollow cylinder; d. moving the device from the first configuration to the second configuration; e. axially displacing the conveying piston from the second position toward the third position, thereby conveying the monomer liquid from the hollow cylinder into the interior space; f. mixing the bone cement powder and the monomer liquid in the mixing unit to prepare the bone cement paste. The device may already be in the first configuration at the beginning of the method; for example, the device may already be in the first configuration when purchased by the user, or the user may move the device into the first configuration at the beginning of the method. If the device comprises a transport lock, this should be removed at the beginning of the method. To fluidically open the monomer liquid container, in method step b. the conveying piston is displaced from the first position, which can be regarded as the starting position of the conveying piston, to the second position while the device is in the first configuration. Since in the first configuration the conveying piston is connected to the opening means, preferably via a driver, the displacement of the conveying piston leads to a displacement of the opening means, which fluidically opens the monomer liquid container. Once the monomer liquid container has been opened, substantially all the monomer liquid flows from the reservoir into the hollow cylinder of the transfer unit in method step c. To convey the monomer liquid from the transfer unit, in particular the hollow cylinder of the transfer unit, into the interior space of the mixing unit, the device is moved from the first configuration to the second configuration. The actual conveying of the monomer liquid takes place in method step e. by axial displacement the conveying piston from the second position toward the third position. The further it is displaced toward the third position, the more monomer liquid located in the hollow cylinder is conveyed into the mixing unit. Therefore, depending on the wishes of the user, the displacement may take place to the third position, or only to an intermediate position between the second position and the third position. The device, in particular the conveying piston, preferably comprises a detachable control element which makes it easier for the user to precisely displace the conveying piston in the hollow cylinder. The control element enables the conveying piston to be displaced to a user-defined intermediate position between the second position and the third position such that a predetermined amount of monomer liquid can be conveyed into the mixing unit, while a remainder of the monomer liquid remains in the transfer unit and is not available for mixing the bone cement paste. By conveying the monomer liquid into the mixing unit, the monomer liquid comes into contact with the bone cement powder in the interior space. By mixing these two starting components, bone cement paste is prepared in the mixing system. Mixing may for example take place using a mixing rod which is reversibly axially displaced in the interior space. One embodiment of the method is characterized in that the movement of the device from the first configuration to the second configuration takes place by way of a rotational movement. In one embodiment, the configuration is changed by rotating the conveying piston. In another embodiment, the configuration is changed by rotating a ring. Both possibilities are described in more detail in the preceding embodiments of the device. The device is characterized in that it prepares a bone cement paste from two starting components. A bone cement paste is understood to mean a substance which is suitable in the field of medical technology for establishing a stable bond between artificial joints, such as hip and knee joints, and bone material. Curing turns bone cement paste into bone cement. These bone cements are preferably polymethyl methacrylate bone cements (PMMA bone cements). PMMA bone cements have been used in medical applications for a long time, and go back to the work of Sir Charnley (cf. Charnley, J., Anchorage of the femoral head prosthesis of the shaft of the femur. J. Bone Joint Surg. 1960; 42, 28-30.). PMMA bone cements can be produced from a bone cement powder as a first starting component and a monomer liquid as a second starting component. Given a suitable composition, the two starting components can be stably stored separately from each other. When the two starting components are brought into contact, the swelling of the polymer components of the bone cement powder produces a plastically deformable bone cement paste. A polymerization of the monomer is initiated by radicals. As the polymerization of the monomer progresses, the viscosity of the bone cement paste increases until it cures completely. A bone cement powder is understood to mean a powder that comprises at least one particulate polymethyl methacrylate and / or a particulate polymethyl methacrylate copolymer. Examples of copolymers are styrene and / or methyl acrylate. In one embodiment, the bone cement powder may additionally comprise a hydrophilic additive which aids the distribution of the monomer liquid within the bone cement powder. In another embodiment, the bone cement powder may additionally comprise an initiator which initiates the polymerization. In another embodiment, the bone cement powder may additionally comprise a radiopaque. In yet another embodiment, the bone cement powder may additionally comprise pharmaceutically active substances, such as antibiotics. Preferably, the bone cement powder comprises, as a hydrophilic additive, at least one particulate polymethyl methacrylate and / or a particulate polymethyl methacrylate copolymer, an initiator, and a radiopaque, or consists of these components. More preferably, the bone cement powder comprises at least one particulate polymethyl methacrylate and / or a particulate polymethyl methacrylate copolymer, an initiator, a radiopaque, and a hydrophilic additive, or consists of these components. Most preferably, the bone cement powder comprises at least one particulate polymethyl methacrylate and / or a particulate polymethyl methacrylate copolymer, an initiator, a radiopaque, a hydrophilic additive, and an antibiotic, or consists of these components. According to the invention, the particle size of the particulate polymethyl methacrylate and / or of the particulate polymethyl methacrylate copolymer of the bone cement powder may correspond to the sieve fraction of less than 150 pm, preferably less than 100 pm. According to the invention, the hydrophilic additive may be particulate and / or fibrous. In another embodiment, the hydrophilic additive may be sparingly soluble, preferably insoluble, in methyl methacrylate. In another embodiment, the hydrophilic additive may have an absorption capacity of at least 0.6 g of methyl methacrylate per gram of hydrophilic additive. In another embodiment, the hydrophilic additive may comprise a chemical substance comprising at least one OH group. It may preferably be provided that the hydrophilic additive has covalently bonded OH groups on its surface. Examples of such preferred hydrophilic additives may be additives selected from the group comprising cellulose, oxycellulose, starch, titanium dioxide, and silicon dioxide, with particular preference being given to fumed silica. In one embodiment, the particle size of the hydrophilic additive may correspond to the sieve fraction of less than 100 pm, preferably less than 50 pm, and most preferably less than 10 pm. The hydrophilic additive may be present in an amount of 0.1 to 2.5 wt.% relative to the total weight of the bone cement powder. According to the invention, the initiator may contain dibenzoyl peroxide or consist of dibenzoyl peroxide. According to the invention, a radiopaque is understood to mean a substance which makes it possible to make the bone cement visible on X-ray diagnostic images. Examples of radiopaques may comprise barium sulfate, zirconium dioxide, and calcium carbonate. According to the invention, the pharmaceutically active substance may comprise one or more antibiotics and optionally added co-factors for the one or more antibiotics. Preferably, the pharmaceutically active substance consists of one or more antibiotics and optionally added co-factors for the one or more antibiotics. Examples of antibiotics include, inter alia, gentamicin, clindamycin, and vancomycin. According to the invention, the monomer liquid may comprise the monomer methyl methacrylate or may consist of methyl methacrylate. In one embodiment, the monomer liquid comprises, in addition to the monomer, an activator dissolved therein, such as N,N-dimethyl-p-toluidine, or consists of methyl methacrylate and N,N-dimethyl-p-toluidine. The features disclosed for the device are also disclosed for the method, and vice versa. Figures The invention is further illustrated by way of example below by means of figures. The invention is not limited to the figures. In the figures: Fig. 1 shows a schematic longitudinal section through one example of a device for preparing a bone cement paste, the device comprising a mixing unit, a reservoir containing a monomer liquid, and a transfer unit, the device being in a first configuration, and a conveying piston being arranged in a first position, Fig. 2 shows the device of Fig. 1 in a second position of the conveying piston, Fig. 3 shows the device of Fig. 1 and 2 in a second configuration and as the monomer liquid is being conveyed from the transfer unit into the mixing unit, Fig. 4 shows the device of Fig. 1 to 3 as the bone cement powder and the monomer liquid are being mixed to prepare the bone cement paste, Fig. 5 shows a schematic longitudinal section through another example of a device for preparing a bone cement paste, the device comprising a mixing unit, a reservoir containing a monomer liquid, and a transfer unit, the device being in a first configuration, and a conveying piston being arranged in a first position, Fig. 6 shows the device of Fig. 5 in a second configuration, Fig. 7 shows the device of Fig. 5 and 6 in an intermediate position of the conveying piston, and Fig. 8 shows a flowchart of a method for preparing a bone cement paste. Description of the figures Fig. 1 shows a schematic longitudinal section through one exemplary embodiment of a device 100 for preparing a bone cement paste from two starting components, in a starting state. The device 100 comprises a mixing unit 200, a reservoir 300, and a transfer unit 400 via which the mixing unit 200 and the reservoir 300 are or can be fluidically connected. The mixing unit 200 serves to mix the starting components of the bone cement paste and comprises an interior space 210, in which a bone cement powder 510 is stored as a first starting component of the bone cement paste to be prepared, and a mixing element 220 in the form of a mixing rod. The mixing element 220 is reversibly displaceable within the interior space 210 and is mounted in such a way as to be rotatable about a longitudinal axis such that mixing blades 225 can ensure homogeneous mixing of the starting components. The mixing unit 200 is reversibly detachably connected to the rest of the device 100 via a thread 230 such that, once the mixing unit 200 has been separated, the bone cement paste prepared therein can be applied from the mixing unit 200 to a desired site. The reservoir 300 comprises a reservoir container 310, in which there is stored a fluidically closed monomer liquid container 320 in the form of an ampule, in particular a glass ampule. Stored within the monomer liquid container 320 is a monomer liquid 520 as a second starting component of the bone cement paste. The transfer unit 200 is arranged spatially between the mixing unit 200 and the reservoir 300. The transfer unit 200 comprises a hollow cylinder 410 and a conveying piston that is axially displaceable in the hollow cylinder 410, which interact as a piston-cylinder system to convey the monomer liquid 520 from the hollow cylinder 410 into the interior space 210. To this end, the hollow cylinder 410 is fluidically connected to the interior space 210 via a connecting line 430 and, at least in the illustrated arrangement of the conveying piston 420 within the hollow cylinder 410, is fluidically connected to the reservoir 300 via a passage 330. The connecting line 460 between the transfer unit 400 and the mixing unit 200 is arranged in a loop with a high apex 465 so as to prevent the monomer liquid 520 from flowing in an uncontrolled manner through the connecting line 460 into the mixing unit 200, in particular into the interior space 210. To ensure that as far as possible the entirety of the monomer liquid 520 is conveyed from the hollow cylinder 410 into the interior space 210, the hollow cylinder 410 and the conveying piston 420 are convex in shape and the connecting element 460 is arranged at the lowest point of the hollow cylinder 410. The device 100 comprises an opening means 430 in the form of a wedge for fluidically opening the monomer liquid container 320. The opening means 430 is axially displaceable above an ampule head 325 of the monomer liquid container 320 such that an axial displacement of the opening means 430 can cause the ampule head 325 to break off, thereby fluidically opening the monomer liquid container 320. In order to displace the opening means 430 in this way, the latter is connected to the conveying piston 420 via a driver 440 in Fig. 1. This means that an axial displacement of the conveying piston 420 within the hollow cylinder 410 is transmitted directly to the opening means 430 by way of the driver 440. The device 100 is thus arranged in a first configuration in Fig. 1, with the conveying piston 420 being in a first position, its starting position. Fig. 2 shows the device of Fig. 1, with the device 100 still being in the first configuration, but with the conveying piston 420 having been displaced axially in the hollow cylinder 410 from its first position shown in Fig. 1 to a second position. In the first configuration, as already described, a displacement of the conveying piston 420 is transmitted directly to the opening means 430 by way of the driver 440. By the displacement of the conveying piston 420 to the second position, the opening means 430 has been pressed against the ampule head 325 of the monomer liquid container 320, which has thus broken off and thereby fluidically opened the monomer liquid container 320. At the moment shown, the monomer liquid 520 is flowing from the fluidically opened monomer liquid container 320, through the passage 330, into the hollow cylinder 410 of the transfer unit 400. In the second position of the conveying piston 420, the opening means 430 bears against a stop 435. The stop 435 blocks any further axial displacement of the opening means 430 in the direction traveled to fluidically open the monomer liquid container 320. Thus, in the first configuration of the device 100, further displacement of the conveying piston 420 from the second position toward a third position is also prevented. By the device 100 remaining in the first configuration, this prevents any conveying, in particular unintentional conveying, of the monomer liquid 520 from the hollow cylinder 410 into the mixing unit 200. To prevent the bone cement paste that is to be prepared from being contaminated with fragments, in particular glass shards, of the fluidically opened monomer liquid container 320, a filter element 340 is located within the reservoir 300 and retains the fragments in the reservoir 300. In particular, the ampule head 325 is retained by the filter element within the reservoir 300 in this embodiment. Fig. 3 shows the device 100 of Fig. 1 and 2, with the device 100 being in a second configuration. In the second configuration, the conveying piston 420 is no longer connected to the opening means 430 by way of the driver 440, so that the conveying piston 420 is also no longer limited, in terms of its freedom of movement within the hollow cylinder 410, by the opening means 430 bearing against the stop 435. The device 100 has been moved from the first configuration to the second configuration by way of a rotational movement 470 (indicated by an arrow) of the conveying piston 420. As a result of the rotational movement 470, the driver 440 is no longer in engagement with the opening means 430. At the moment shown, the conveying piston has been axially displaced in the hollow cylinder 410 from its second position toward a third position, which on the one hand has fluidically closed the passage 330 and on the other hand has initiated the conveying of the monomer liquid 520 from the transfer unit 400 into the mixing unit 200 via the connecting line 460. Fig. 4 shows the device 100 of Fig. 1 to 3 during the preparation of the bone cement paste 500. The device 100 is still in the second configuration, as shown in Fig. 3, with the conveying piston 420 having been displaced to the third position. This has resulted in substantially all the monomer liquid 520 (only residues remain in the connecting line 460) having been conveyed into the mixing unit 200, where the two starting components have been mixed by repeatedly displacing and rotating the mixing element 220 to prepare the bone cement paste 500. Therefore, once the mixing unit 200 has been separated from the rest of the device 100, the bone cement paste 500 is ready to be discharged at a desired site. Fig. 5 shows a schematic longitudinal section through another exemplary embodiment of a device 100' for preparing a bone cement paste from two starting components, in a starting state. The embodiment shown in accordance with Fig. 5 largely corresponds to the embodiment described above and shown in the preceding figures, as well as to the use thereof, and therefore reference is made to the above description in order to avoid repetitions. Any structure that is repeated from the description of the preceding figures has the same reference sign with an apostrophe. In a manner analogous to the device 100 in Fig. 1, the device 100' is in a first configuration and the conveying piston 420' is in the first position. The device 100' comprises a detachable transport lock 110 on the opening means 430', which prevents unintentional displacement of the opening means 430' and thus fluidic opening of the monomer liquid container 320'. Furthermore, in contrast to the device 100 of Fig. 1 to 4, the device 100' comprises a plurality of, in particular 4, control elements 450 that can be detached from the conveying piston 420'. The control elements 450 allow a user of the device 100' to displace the conveying piston 420' only to an intermediate position, predetermined by the individual control element 450, between the second position and the third position of the conveying piston 420' in the hollow cylinder 410' and thus to convey only a predetermined proportion of the monomer liquid 520' located therein into the mixing unit 200'. In the illustrated embodiment of the device 100', the driver 440' is arranged on a ring that is rotatable around the conveying piston 420', in particular a cap-like ring. Moving the device 100' from the first configuration to a second configuration is thus made possible by rotating the ring 445, and not by rotating the conveying piston 420 itself as in the case of the device 100 of Fig. 1 to 4. Fig. 6 shows the device 100' of Fig. 5 after the monomer liquid container 320' has been fluidically opened. To this end, the transport lock 110 has been removed and the conveying piston 420' has been axially displaced within the hollow cylinder 410' from the first position to a second position. At the moment shown, substantially all the monomer liquid 520' is already in the hollow cylinder 410', and the conveying piston 420' has been separated from the opening means 430 by a rotational movement 470' (indicated by an arrow) of the ring 445, which has moved the device 100' from the first configuration to a second configuration. Fig. 7 shows the device 100' of Fig. 5 and 6, with the device 100' still being in the second configuration and the conveying piston 420' having been displaced from the second position in Fig. 6 to an intermediate position between the second position and a third position. In the embodiment shown, the intermediate position is determined by the presence of one of the control elements 450, which prevents further insertion of the conveying piston 420' into the hollow cylinder 410' to the third position. To this end, the two lower control elements 450 (see Fig. 5 or 6) have been removed, and the control element formerly third from the bottom defines the intermediate position. This enables predetermined conveying of only a portion of the monomer liquid 520' from the transfer unit 200' into the mixing unit, while the remainder of the monomer liquid 520' remains in the hollow cylinder 410', at least until the remaining control element 450 has been removed from the conveying piston 420' and the conveying piston 420' has been further displaced to the third position. A specific mixing ratio of the starting components can thus be achieved in the bone cement paste. The bone cement paste can be mixed and prepared in a manner analogous to the embodiment of the device 100 of Fig. 1 to 4. Fig. 8 shows a method 600 for preparing a bone cement paste 520 from two starting components by means of the above-described devices 100, 100' of Fig. 1 to 4 and 5 to 7, the method comprising method steps 610 to 660. A bone cement powder 510, 510' as a first starting component is stored in the interior space 210, 210' of the mixing unit 200, 200', and a monomer liquid container 320, 320' filled with a monomer liquid 520, 520' as a second starting component is stored in the reservoir container 310, 310' of the reservoir 300, 300'. In a method step 610, the device 100, 100' is provided in the first configuration. The first configuration may for example be installed by a user of the device 100, 100', or the user of the device 100, 100' may for example have purchased it already in the first configuration. If the device 100, 100' comprises a transport lock 110, this should preferably be removed prior to the subsequent method steps. In a method step 620, the conveying piston 420, 420' is axially displaced from the first position, which is preferably the starting position of the conveying piston 420, 420', to the second position, thereby fluidically opening the monomer liquid container 320, 320'. For clarification, it should be pointed out once again that the device 100, 100' is in the first configuration for this method step, so that the displacement of the conveying piston 420, 420' is transmitted to the opening means 430, 430'. Preferably, the displacement of the conveying piston 420, 420' takes place as a result of force being exerted on the conveying piston 420, 420’ by the user of the device 100, 100'. As an alternative or in addition, the displacement of the conveying piston 420, 420' may also be initiated by a vacuum applied to the device 100, 100', in particular to the interior space 210, 210'. This also applies to any further displacement of the conveying piston 420, 420' in the course of the method 600. In a method step 630, the monomer liquid 520, 520' flows from the reservoir 300, 300' into the hollow cylinder 410, 410'. Preferably, the monomer liquid 520, 520' flows under the effect of gravity. For this to happen, the device 100, 100' must be spatially oriented accordingly. In a method step 640, the device 100, 100' is moved from the first configuration to the second configuration. This preferably takes place by way of a rotational movement 470, 470', preferably of the conveying piston 420 or the ring 445. In a method step 650, the conveying piston 420, 420’ is axially displaced from the second position toward the third position, thereby conveying the monomer liquid 520, 520' from the hollow cylinder 410, 410' into the interior space 210, 210'. The further the conveying piston 420, 420' is displaced toward the third position, the more monomer liquid 520, 520' located in the hollow cylinder 410, 410' is conveyed into the interior space 210, 210', until, upon reaching the third position, substantially all the monomer liquid 520, 520' would be or is conveyed. The amount of monomer liquid 520, 520' conveyed can thus be determined by the user of the device 100, 100'. The user can be assisted in this by using control elements 450. In a method step 660, the bone cement powder 510, 510' and the monomer liquid 520, 520' are mixed to prepare the bone cement paste 500. The bone cement paste 500 can then be discharged from the mixing unit 200, 200’ to the site desired by the user. To this end, the mixing unit 200, 200' can preferably be separated from the rest of the device 100, 100', and discharging from the interior space 210, 210' can take place by means of a discharge device, preferably by means of a discharge piston that is displaceable inside the interior space 210, 210'. Reference signs 100, 100' device 110 transport lock 200, 200' mixing unit 210, 210' interior space 220, 220' mixing element 225, 225' mixing blade 230, 230' thread 300, 300' reservoir 310, 310' reservoir container 320, 320' monomer liquid container 325, 325' ampule head 330, 330' passage 340, 340' filter element 350 transport lock 400, 400' transfer unit 410, 410' hollow cylinder 420, 420' conveying piston 430, 430' opening means 435, 435' stop 440, 440' driver 445 ring 450 control element 460, 460' connecting line 465, 465' apex 470, 470' rotational movement 500 bone cement paste 510, 510' bone cement powder 520, 520' monomer liquid 600 method 610 provide 620 displace 630 flow 640 move 650 displace 660 mix
Claims
1. A device (100, 100’) for preparing a bone cement paste (500) from two starting components, the device comprisinga mixing unit (200, 200') comprising an interior space (210, 210') in which a bone cement powder (510, 510') as a first starting component is or can be stored,a reservoir (300, 300') comprising a reservoir container (310, 310') in which at least one fluidically closed monomer liquid container (320, 320') filled with a monomer liquid (520, 520') as a second starting component is or can be stored,a transfer unit (400, 400') comprising a hollow cylinder (410, 410') and a conveying piston (420, 420') that is axially displaceable in the hollow cylinder (410, 410'),wherein the mixing unit (200, 200') and the reservoir (300, 300') are or can be fluidically connected to each other via the hollow cylinder (410, 410'),wherein the monomer liquid container (320, 320') in the device (100, 100') is to be opened in such a way that the monomer liquid (520, 520') can flow from the reservoir (300, 300') into the hollow cylinder (410, 410') via a passage (330, 330') and can be conveyed from the hollow cylinder (410, 410') into the interior space (210, 210') by axial displacement of the conveying piston (420, 420') in the hollow cylinder (410, 410'), characterized in thatin a first configuration of the device (100, 100') the conveying piston (420, 420') is connected to an opening means (430, 430') such that an axial displacement of the conveying piston (420, 420') from a first position to a second position pushes the opening means (430, 430') against the monomer liquid container (320, 320') such that the monomer liquid container (320, 320') can be fluidically opened by the opening means (430, 430') and the monomer liquid (520, 520') can flow from the reservoir (300, 300') into the hollow cylinder (410, 410') via the passage (330, 330'), and in thatin a second configuration of the device (100, 100') the conveying piston (420, 420') is separated from the opening means (430, 430') such that the monomer liquid (520, 520') can be conveyed from the hollow cylinder (410, 410') into the interior space (210, 210') by a further axial displacement of the conveying piston (420, 420') from the second position toward a third position.
2. The device (100, 100') according to claim 1, wherein in the first configuration the conveying piston (420, 420') is displaceable only between the first position and the second position.
3. The device (100, 100') according to claim 2, wherein in the first configuration the opening means (430, 430') bears against a stop (435, 435') in the second position of the conveying piston (420, 420') such that further axial displacement from the second position toward the third position is prevented.
4. The device (100, 100') according to any of the preceding claims, wherein the opening means (430, 430') is a wedge.
5. The device (100, 100') according to claim 4, wherein the wedge comprises at least one through-opening such that the monomer liquid (520, 520') can flow from the reservoir (300, 300') into the hollow cylinder (410, 410') through the through-opening and the passage (330, 330').
6. The device (100, 100') according to any of the preceding claims, wherein the monomer liquid container (320, 320') is an ampule and is stored in the reservoir container (310, 310'), wherein the opening means (430, 430') is arranged axially above an ampule head (325, 325') of the ampule such that, when the conveying piston (420, 420') is displaced from the first position to the second position in the first configuration of the device (100, 100'), the opening means (430, 430') can be pressed against the ampule head (325, 325') and thus the ampule can be fluidically opened.
7. The device (100, 100') according to any of the preceding claims, wherein the conveying piston (420, 420') and the opening means (430, 430') are connected to each other via a driver (440, 440') in the first configuration.
8. The device (100, 100') according to claim 7, wherein the driver (440, 440') is separated from the opening means (430, 430') when the device (100, 100') is moved from the first configuration to the second configuration.
9. The device (100) according to claim 8, wherein the movement of the device (100) from the first configuration to the second configuration can be achieved by rotating the conveying piston (420) about a conveying piston longitudinal axis.
10. The device (100') according to claim 8, wherein the driver (440') is arranged on a ring (445) around the conveying piston (420') such that the movement of the device (100') from the first configuration to the second configuration can be achieved by rotating the ring (445) around the conveying piston (420').
11. The device (100') according to any of the preceding claims, wherein the device (100') comprises a transport lock (110) which prevents unintentional displacement of the opening means (430').
12. The device (100') according to any of the preceding claims, wherein the conveying piston (420') comprises at least one detachable control element (450) which limits the displacement of the conveying piston (420') between the second position and the third position to an intermediate position.
13. The device (100, 100') according to any of the preceding claims, wherein the conveying piston (420, 420') fluidically closes the passage (330, 330') when axially displaced from the second position toward the third position.
14. A method (600) for preparing a bone cement paste (500) from two starting components by means of a device (100, 100') according to any of claims 1 to 13, wherein a bone cement powder (510, 510') as a first starting component is stored in the interior space (210, 210') and a fluidically closed monomer liquid container (320, 320') filled with a monomer liquid (520, 520') as a second starting component is stored in the reservoir container (310, 310'), the method comprising the method steps of:a. providing (610) the device (100, 100') in the first configuration;b. axially displacing (620) the conveying piston (420, 420') from the first position to the second position, thereby fluidically opening the monomer liquid container (320, 320');c. allowing the monomer liquid (520, 520') to flow (630) from the reservoir (300, 300') into the hollow cylinder (410, 410');d. moving (640) the device (100, 100') from the first configuration to the second configuration;e. axially displacing (650) the conveying piston (420, 420') from the second position toward the third position, thereby conveying the monomer liquid (520, 520') from the hollow cylinder (410, 410') into the interior space (210, 210');f. mixing (660) the bone cement powder (510, 510') and the monomer liquid (520, 520') in the mixing unit (200, 200') to prepare the bone cement paste (500).
15. The method (600) according to claim 14, wherein the movement (640) of the device (100, 100') from the first configuration to the second configuration takes place by way of a rotational movement (470, 470').