Bone cement mixing system with improved monomer liquid transfer

Abstract

The present invention relates to a device for mixing bone cement, comprising: a cartridge 101 for receiving a bone cement powder; a container 102 for receiving a monomer liquid 118, wherein the container is fluidically connected to the cartridge; a cartridge head 104 which is arranged at a proximal end 103 of the cartridge, wherein the cartridge head has a feed-through 105; an inlet tube 106, wherein the inlet tube has a longitudinal axis 107; and a funnel-shaped outlet, wherein the funnel-shaped outlet has a funnel inner surface 109 which is arranged at least partly at an angle of no more than 60° relative to the longitudinal axis of the inlet tube; wherein the device is designed and configured to transfer a monomer liquid from the container into the cartridge by means of free gravitational flow via the funnel-shaped outlet and the inlet tube.

Description

[0001] DESCRIPTION

[0002] Bone cement mixing system with improved monomer fluid transfer

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to the field of medical technology, in particular to devices for producing a PMMA bone cement and for storing components thereof.

[0005] STATE OF THE ART

[0006] Polymethyl methacrylate bone cements are based on the fundamental work of Charnley. Polymethyl methacrylate bone cements typically consist of a liquid monomer component and a powder component. The monomer component can, for example, contain the monomer methyl methacrylate and an activator dissolved therein (e.g., N,N-dimethyl-p-toluidine). The powder component, also referred to as bone cement powder, can contain one or more polymers based on methyl methacrylate and comonomers such as styrene, methyl acrylate, or similar monomers, which can be produced by polymerization, preferably suspension polymerization. The powder component can also contain an X-ray opaque agent and an initiator such as dibenzoyl peroxide. When the powder component is mixed with the monomer component, swelling of the polymers of the powder component in the methyl methacrylate can produce a plastically deformable dough—the actual bone cement dough.When the powder component is mixed with the monomer component, the activator N,N-dimethyl-p-toluidine, for example, reacts with dibenzoyl peroxide to form radicals. The resulting radicals can initiate the radical polymerization of the methyl methacrylate. As the polymerization of the methyl methacrylate progresses, the viscosity of the cement paste increases until it solidifies.

[0007] Polymethyl methacrylate bone cements can be mixed in suitable mixing cups using spatulas by mixing the powder component with the monomer liquid. This may result in the inclusion of air bubbles in the bone cement mixture, which can negatively affect the mechanical properties of the cured bone cement.

[0008] To avoid air inclusions in the bone cement dough, a variety of vacuum cementing systems have been described, of which the following are examples: 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 1 020 167 A2, US 5,586,821 A, EP 1 016452 A2, DE 3640 279 A1, WO 94 / 26403 A1, EP 1 005 901 A2, US 5,344,232 A.

[0009] A further development in cementing technology is represented by cementing systems in which both the cement powder and the monomer liquid are already packaged in separate compartments of the mixing systems and are only mixed together in the cementing system immediately before the cement is applied. Such closed "fully prepacked mixing systems" are described in the patent documents EP0380867B1, EP0796653B1, EP0692229B1, US5997544A, US6709149B1 , DE69812726T2 and US5588745A, WO9416951A1, DE19718648A1 , EP1741413B1 , EP3054880B1 , DE102009031178B3, US8662736B2, EP2269718B1 , EP2281532B1 and EP3093067B1.

[0010] Fully prepackaged mixing systems present several challenges. Safe, reproducible transfer of the monomer liquid into the polymethyl methacrylate bone cement powder is desirable, as is avoiding uncontrolled mixing of the components during storage. It is advantageous if the cement powder cannot penetrate the monomer liquid transfer conduit during transport and storage of the mixing system. Otherwise, the conduit can become blocked during monomer transfer due to swelling and sticking. Blockage of the conduit by swollen, sticky bone cement could interrupt the monomer liquid transfer and prevent the cement components from mixing in the predetermined ratio.

[0011] In the fully prepacked mixing systems according to EP0796653, US6709149, EP1741413, EP3054880, EP2269718B1, and EP2281532B1, monomer transfer occurs by applying an external vacuum to the cartridge via a vacuum connection and a porous plate. This means that the monomer liquid is drawn into the cartridge by the applied vacuum. In the mixing system described in EP3093067B1, the monomer liquid can be transferred into the cartridge either by vacuum or, alternatively, by pressure transfer of the monomer liquid using a manually operated pump piston integrated into the mixing system.

[0012] According to EP2281532B1, the blockage of the conduit for transferring the monomer liquid is avoided by using a mesh or pore disc permeable to the monomer liquid to block the cement powder particles, wherein the mesh or pore disc is part of a special nozzle that generates a sharp monomer liquid jet during transfer, which displaces swollen cement particles, so that a complete monomer liquid transfer into the bone cement powder is possible.

[0013] The mixing system described in EP1741413B1 and EP3054880B1 uses rubber caps placed on hollow mandrels to prevent the migration of powder component particles. Before monomer transfer, these rubber caps are pierced by the hollow mandrels and are then opened for monomer liquid transfer.

[0014] PREFERRED EMBODIMENTS

[0015] An object of the present invention is to solve one or more of the above-described and other problems of the prior art. For example, the invention provides a device for storing and mixing bone cement that allows for simple and reliable mixing of a monomer liquid with a powder component of a PMMA bone cement by gravitational flow to produce a ready-to-use PMMA bone cement dough.

[0016] These objects are achieved by the methods, devices, kits and medical uses described herein, in particular those described in the patent claims.

[0017] Preferred embodiments of the invention are described below.

[0018] A first embodiment relates to a device for mixing bone cement, comprising a cartridge for receiving a PMMA bone cement powder; a container for receiving a monomer liquid, wherein the container is fluidly connected to the cartridge; a cartridge head arranged at a proximal end of the cartridge, wherein the cartridge head has a passage; an inlet tube, wherein the inlet tube has a longitudinal axis; and a funnel-shaped outlet, wherein the funnel-shaped outlet has a funnel inner surface that is at least partially arranged at an angle of no more than 60° to the longitudinal axis of the inlet tube; wherein the device is designed and configured to transfer a monomer liquid from the container into the cartridge by free gravitational flow via the funnel-shaped outlet and the inlet tube.

[0019] A second embodiment relates to a device according to the first embodiment, wherein the inlet pipe has an inner diameter i of 4.0 mm to 10.0 mm.

[0020] A third embodiment relates to a device according to one of the preceding embodiments, wherein the inlet pipe has a length L and an inner diameter i, and wherein the ratio L : i of length L to inner diameter i is in a range from "L : i = 1 : 10" to "L : i = 1 : 3.5".

[0021] A fourth embodiment relates to a device according to one of the preceding embodiments, wherein the funnel-shaped outlet is further designed and arranged to allow a PMMA bone cement powder to flow out into the cartridge by free gravitational flow.

[0022] A fifth embodiment relates to a device according to one of the preceding embodiments, which further comprises a means for eliminating PMMA bone cement powder bridges in the outlet, wherein the means for eliminating PMMA bone cement powder bridges is preferably a sphere, wherein the sphere is further preferably arranged movably in the funnel-shaped outlet.

[0023] A sixth embodiment relates to a device according to one of the preceding embodiments, wherein the funnel inner surface forms an angle of not more than 60°, preferably not more than 55°, more preferably an angle of 21° to 50°, to the longitudinal axis of the inlet pipe over at least 50% of its total area.

[0024] A seventh embodiment relates to a device according to one of the preceding embodiments, wherein the cartridge comprises a PMMA bone cement powder, and / or wherein the container comprises a monomer liquid. An eighth embodiment relates to a device according to one of the preceding embodiments, wherein the funnel-shaped outlet has a tapered end that is directly fluidically connected to the inlet tube.

[0025] A ninth embodiment relates to a device according to one of the preceding embodiments, wherein the container further comprises a filter permeable to a monomer liquid, wherein the filter is preferably arranged and configured to prevent the penetration of glass splinters from the container into the cartridge, and wherein the filter preferably has a surface area of ​​at least 5 cm on one side of the filter. 2 , further preferably at least 10 cm 2 , even more preferably 15 cm2 has.

[0026] A tenth embodiment relates to a device according to one of the preceding embodiments, wherein an interior of the funnel-shaped outlet and an interior of the cartridge together form a continuous cavity.

[0027] An eleventh embodiment relates to a device according to any one of the preceding embodiments, wherein the funnel-shaped outlet is designed and arranged to prevent the formation of a meniscus when a monomer liquid is transferred from the container into the cartridge by free gravitational flow via the funnel-shaped outlet.

[0028] A twelfth embodiment relates to a device according to one of the preceding embodiments, further comprising a piston for dispensing bone cement from the device, wherein the piston is arranged at least partially in the cartridge and delimits the cartridge to the outside, and wherein the piston preferably has a releasable lock.

[0029] A thirteenth embodiment relates to a device according to one of the preceding embodiments, further comprising a mixing rod, wherein the mixing rod preferably has a closable discharge tube, wherein the discharge tube is preferably designed and configured to discharge a bone cement dough mixed in the device from the device.

[0030] A fourteenth embodiment relates to a device according to any one of the preceding embodiments, wherein the container further comprises a carrier for receiving an ampoule. A fifteenth embodiment relates to a device according to any one of the preceding embodiments, wherein the container further comprises a means for opening a foil pouch or a glass ampoule within the device.

[0031] A sixteenth embodiment relates to a device according to any one of the preceding embodiments, wherein the device is designed and configured to allow venting of the cartridge through the funnel-shaped outlet while a monomer liquid is transferred from the container into the cartridge by free gravitational flow via the funnel-shaped outlet and the inlet tube.

[0032] A further aspect relates to a method for producing a bone cement dough, the method comprising the following steps,

[0033] Providing a device according to one of the preceding embodiments; optionally introducing a monomer liquid into the container; optionally introducing a PMMA bone cement powder into the cartridge; optionally allowing the PMMA bone cement powder to flow out of the funnel-shaped outlet and out of the inlet tube into the cartridge;

[0034] Arranging the device so that the monomer liquid can be transferred from the container into the cartridge by free gravitational flow via the funnel-shaped outlet and the inlet tube;

[0035] Transferring the monomer liquid from the container into the cartridge by free gravitational flow;

[0036] Mixing the monomer liquid with the PMMA bone cement powder in the cartridge to obtain a bone cement dough.

[0037] A further aspect relates to the use of a device according to one of the preceding embodiments or the above-mentioned method for producing bone cement dough, in particular PMMA bone cement dough.

[0038] BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 shows an embodiment of a device according to the invention.

[0040] Figure 2 shows a section of a device according to the invention. Figure 3 shows a device according to the invention containing a glass ampoule with monomer liquid and PMMA bone cement powder.

[0041] Figure 4 shows a device in which monomer liquid enters the cartridge of the device through a funnel-shaped outlet and an inlet tube.

[0042] Figure 5 shows a device in which a monomer liquid and a PMMA bone cement powder are mixed into a bone cement dough using a mixing rod.

[0043] Figure 6 shows a device in which bone cement dough is dispensed from the device through a dispensing tube using a threaded rod and a piston.

[0044] DETAILED DESCRIPTION

[0045] For the embodiments described herein, whose elements "have," "contain," or "comprise" a specific feature (e.g., a material), a further embodiment is always contemplated in which the element in question consists solely of the feature, i.e., does not comprise any further components. The word "comprise" or "comprising" is used herein synonymously with the word "contain," "containing," "have," or "having."

[0046] When an embodiment refers to an element in the singular, an embodiment in which multiple elements are present is also contemplated. The use of a plural term for an element generally encompasses an embodiment in which only a single corresponding element is included.

[0047] Unless otherwise stated or clearly excluded by the context, it is fundamentally possible and hereby clearly contemplated that features of different embodiments may also be present in the other embodiments described herein. Likewise, it is fundamentally contemplated that all features described herein in connection with a method are also applicable to the products, devices, kits, and uses described herein, and vice versa. Merely for the sake of conciseness, all of these contemplated combinations are not explicitly listed in all cases. Technical solutions that are known to be equivalent to the features described herein are also intended to be encompassed by the scope of the invention.

[0048] A first embodiment relates to a device for mixing bone cement, which device comprises a cartridge for receiving a PMMA bone cement powder; a container for receiving a monomer liquid, wherein the container is fluidly connected to the cartridge; an inlet tube; and a funnel-shaped outlet, wherein the device is designed and configured to transfer a monomer liquid from the container into the cartridge by free gravitational flow via the funnel-shaped outlet and the inlet tube.

[0049] A further embodiment relates to a device for mixing bone cement, comprising a cartridge for receiving a PMMA bone cement powder; a container for receiving a monomer liquid, wherein the container is fluidically connected to the cartridge; a cartridge head arranged at a proximal end of the cartridge, wherein the cartridge head has a passage; an inlet tube, wherein the inlet tube has a longitudinal axis; and a funnel-shaped outlet, wherein the funnel-shaped outlet has a funnel inner surface that is at least partially arranged at an angle of no more than 60° to the longitudinal axis of the inlet tube; wherein the device is designed and configured to transfer a monomer liquid from the container into the cartridge by free gravitational flow via the funnel-shaped outlet and the inlet tube.

[0050] The device contains a cartridge suitable for holding a PMMA bone cement powder. The cartridge can, for example, have a substantially cylindrical housing. The housing can, for example, comprise or consist of a plastic. The cartridge can contain a PMMA bone cement powder. A PMMA bone cement powder is a powdered component that can be used to produce a hardenable, i.e., polymerizable, bone cement dough. A PMMA bone cement powder is also referred to herein as the powder component of a bone cement. A PMMA bone cement powder can comprise one or more polymers. Such polymers can be produced by polymerization based on methyl methacrylate and comonomers, such as styrene or methyl acrylate.

[0051] By mixing a PMMA bone cement powder with a monomer liquid, a bone cement dough can be formed that can harden into a PMMA bone cement. A monomer liquid can, for example, comprise the monomer methyl methacrylate and an activator dissolved therein. An example of an activator is N,N-dimethyl-p-toluidine. Accordingly, a PMMA bone cement powder and a monomer liquid each represent components that can be mixed together to form a bone cement dough that can harden into a bone cement. A PMMA bone cement powder and a monomer liquid thus each represent precursor substances (i.e., components) for producing a bone cement, in particular a PMMA bone cement.

[0052] The cartridge has a proximal end at which a cartridge head is arranged. The cartridge head can be detachably connected to the cartridge, e.g., using a thread. The cartridge head can serve as a closure for the cartridge. The cartridge head can further comprise a passage. The passage can be configured to accommodate a mixing rod. Using a mixing rod, a PMMA bone cement powder and a monomer liquid can be mixed within the cartridge. The mixing rod can comprise vanes to facilitate the mixing of these two components.

[0053] The cartridge head can further comprise an opening for connecting a dispensing tube. Such a dispensing tube can be used to dispense bone cement paste from the device. An opening for connecting a dispensing tube can also be arranged at a different position on the cartridge. The opening can be reversibly closable, for example, by a threaded plug. The opening can comprise a thread configured to establish a reversible connection with a closure and / or a dispensing tube.

[0054] In one embodiment, the device has a closure that closes this opening, preferably closes it reversibly.

[0055] Alternatively or additionally, the cartridge head may have an opening to accommodate the inlet tube. The inlet tube may be insertable into the cartridge through the opening to establish a fluid-conducting connection between the container and the cartridge.

[0056] In one embodiment, the device comprises a means for securing, preferably releasably securing, the inlet tube to the cartridge. In one embodiment, the closure is configured to engage the securing means.

[0057] The opening for receiving the inlet pipe can be closed, for example, by a sliding closure. The sliding closure can be designed to engage a notch in the inlet pipe.

[0058] An opening in the cartridge head can be configured to selectively accommodate a discharge tube or the inlet tube. The device further comprises a container for holding a monomer liquid. The container can have a holder for a glass ampoule. A monomer liquid can be provided in a glass ampoule and can be accommodated in such a holder of the container. This can prevent undesirable chemical reactions of the monomer liquid during storage. The container can also have a holder for a foil bag. A monomer liquid can also be provided in a sealed foil bag.

[0059] The holder can preferably be arranged at an angle of 21° to 50° to the longitudinal axis of the cartridge or to the longitudinal axis of the funnel-shaped outlet. This can improve the transfer of the monomer liquid into the cartridge.

[0060] The device further comprises a funnel-shaped outlet and an inlet tube. Using the outlet and the inlet tube, a monomer liquid can be transferred from the container into the cartridge to enable mixing of the monomer liquid with the PMMA bone cement powder within the cartridge. The outlet can be configured, for example, as a funnel-shaped taper of the container, which taper can be directly connected to the inlet tube. The inlet tube can be connected to the cartridge on the side opposite the funnel-shaped outlet. Thus, a monomer liquid can enter the cartridge via the funnel-shaped outlet and the inlet tube by free gravitational flow. In some embodiments, the inlet tube can be reversibly detachably connected to the cartridge.

[0061] "Free gravity flow" herein means that a monomer liquid can flow from the container into the cartridge solely through the action of gravity, without, for example, a pressure difference between the container and the cartridge being required for the transfer of the monomer liquid. Preferably, the devices described herein allow complete transfer of the monomer liquid from the container into the cartridge by free gravity flow within 20 seconds.

[0062] The funnel-shaped outlet can, for example, have a shape defined by a linear or rotating extrusion of a triangle. The funnel-shaped outlet can thus, for example, have the shape of a cone or semicone. The outlet can also have the shape of a pyramid or a truncated pyramid. "Funnel-shaped" here therefore means that the interior of the outlet tapers uniformly, at least in sections, toward the inlet tube. The funnel-shaped outlet has a funnel-shaped inner surface. This funnel-shaped inner surface is arranged at an angle to a longitudinal axis of the inlet tube, which is preferably at most 60°. This ensures that the funnel-shaped outlet is sufficiently steep to ensure free flow of the monomer liquid into the cartridge.

[0063] The inlet pipe is preferably cylindrical. In one embodiment, the inner wall of the inlet pipe is cylindrical.

[0064] The funnel-shaped outlet may have a transparent area. This may allow a user of the device to visually verify the complete drainage of monomer fluid and / or PMMA bone cement powder from the outlet from the outside.

[0065] The inlet pipe preferably has an inner diameter i of 4.0 mm to 10.0 mm. More preferably, the inner diameter i of the inlet pipe can be 4.0 mm to 8.0 mm.

[0066] 5.0 mm to 8.0 mm; or 4.0 mm to 6.0 mm. For example, the inner diameter i is at least 4.0 mm. Diameters of less than 4 mm can lead to the formation of a meniscus in the monomer liquid, which can prevent the monomer liquid from flowing freely. In addition, diameters of less than 4 mm often result in powder bridges forming in the PMMA bone cement powder.

[0067] In one embodiment, the inlet tube has a length L and an inner diameter i. The length L is the shortest distance between the two ends of the inlet tube. The ends of the inlet tube can be defined as the points at which the inlet tube is connected to the funnel-shaped outlet or cartridge. Preferably, the ratio L:i of length L to inner diameter i of the inlet tube is in a range from "L:i = 1:10" to "L:i = 1:3.5." This range is favorable for ensuring the outflow of monomer liquid from the inlet tube and the simultaneous ascent of air into the inlet tube to allow pressure equalization in the device.

[0068] The length L of the inlet tube is preferably selected such that, during use of the device, the inlet tube has no contact with any PMMA bone cement powder in the cartridge. This can prevent the PMMA bone cement powder from sticking together during the transfer of monomer fluid. This particularly refers to an "upright" orientation of the device, which allows a free gravitational flow of monomer fluid "downward" (i.e., in the direction of gravity) into the cartridge. In such an orientation, the longitudinal axis of the inlet tube and its opening, which is arranged toward the cartridge, point "downward" (i.e., in the direction of gravity).

[0069] For example, the inlet tube extends only 10%, 20%, or at most 30% of the cartridge length into the cartridge. The cartridge length is defined as the length of the cartridge along the cartridge's longitudinal axis.

[0070] In one embodiment, the funnel-shaped outlet is designed and arranged to allow PMMA bone cement powder to flow into the cartridge by free gravitational flow. Even if the PMMA bone cement powder is arranged in the cartridge, some PMMA bone cement powder can, for example, pass through the inlet tube into the outlet during transport of the device. To prevent undesired mixing of the PMMA bone cement powder with monomer liquid, the outlet can be designed and arranged such that, in such a case, the PMMA bone cement powder can flow back into the cartridge automatically. For this purpose, a sufficiently steep design and arrangement of the funnel-shaped outlet can be particularly important, optionally in conjunction with the inlet tube, as described herein.This can prevent the PMMA bone cement powder from sticking in the outlet or inlet tube during the transfer of monomer liquid.

[0071] In one embodiment, the device further comprises a means for eliminating PMMA bone cement powder bridges in the outlet. The means for eliminating PMMA bone cement powder bridges can, for example, be a sphere. Preferably, the sphere can be movably arranged in the funnel-shaped outlet. The sphere can destabilize bone cement powder bridges by moving within the interior of the outlet, so that the PMMA bone cement powder becomes free-flowing and can be released from the outlet into the cartridge by gravitational flow. Similarly, other suitable means can be used to destabilize powder bridges of the PMMA bone cement powder or prevent their formation. For example, mesh-like or rod-like structures can be arranged in the funnel-shaped outlet, which act like a sieve or rake to prevent powder bridges.Preferred means for eliminating PMMA bone cement powder bridges are those that do not significantly slow the flow of PMMA bone cement powder or monomer liquid, such as a ball. The ball preferably has a diameter larger than the inner diameter of the inlet tube, for example, at least 1.5 times the inner diameter of the inlet tube. This prevents unwanted blockage of the inlet tube by the ball.

[0072] The sphere preferably has a density of at least 1.0 g / cm 3The ball may comprise a material selected from the group consisting of glass, ceramic, metal, metal oxide, plastic, and combinations thereof. Preferred ceramics are corundum (Al2O3) or porcelain. Porcelain is a ceramic composition comprising kaolin, quartz, and feldspar. Preferred metals are stainless steel or tantalum. Examples of stainless steel are alloys 316L, 301, and 304.

[0073] In some embodiments, the inner surface of the funnel-shaped outlet forms an angle of no more than 60° to the longitudinal axis of the inlet tube over at least 50% of its total area. This achieves a steep geometry that enables reliable drainage of monomer liquid or PMMA bone cement powder from the outlet and via the inlet tube into the cartridge by gravity flow.

[0074] In some embodiments, the funnel inner surface of the funnel-shaped outlet forms an angle of no more than 55°, more preferably an angle of 21° to 50°, to the longitudinal axis of the inlet pipe over at least 50% of its total area.

[0075] In some embodiments, the inner surface of the funnel-shaped outlet forms an angle of 21° to 60° to the longitudinal axis of the inlet pipe over at least 50% of its total area.

[0076] In some embodiments, the cartridge contains a PMMA bone cement powder. The PMMA bone cement powder is preferably arranged in an interior space of the cartridge.

[0077] In some embodiments, the container comprises a monomer liquid. The monomer liquid is preferably disposed within an interior space of the container. The monomer liquid can be disposed in a glass ampoule or in a sealed foil pouch within the container.

[0078] In some embodiments, the funnel-shaped outlet has a tapered end. The tapered end can be directly fluidically connectable to the inlet tube. The funnel-shaped outlet can directly merge into the inlet tube at a tapered end of the outlet. Such a direct transition allows unhindered flow of PMMA bone cement powder from the outlet via the inlet tube and into the cartridge.

[0079] In some embodiments, the container further comprises a filter permeable to a monomer liquid. The filter is preferably arranged and configured to prevent glass splinters from the container from penetrating the cartridge. The device can be configured to receive a glass ampoule containing monomer liquid. The device can further be configured to break open a glass ampoule containing monomer liquid. The glass ampoule can in particular be received and broken open within the container. For this purpose, the container can have a receptacle for a glass ampoule. The container can have a means for breaking open a glass ampoule. For example, the container can have a projection that is arranged and configured to break off the head of a glass ampoule.

[0080] The filter can be designed to retain fragments of a glass ampoule in the container. This can prevent glass fragments from entering the cartridge. This can prevent contamination of bone cement paste with glass fragments. Preferably, the filter can have a surface area of ​​at least 5 cm on one side. 2 , further preferably at least 10 cm 2 , even more preferably 15 cm 2 This area corresponds to the area that is geometrically derived directly from the "filter diameter" commonly used in the field.

[0081] The filter may preferably be arranged on a side of the outlet opposite the inlet pipe.

[0082] In some embodiments, an interior of the funnel-shaped outlet and an interior of the cartridge together form a continuous cavity. This means that the interiors of the outlet and cartridge are connected in such a way that PMMA bone cement powder can flow unhindered from the outlet into the cartridge.

[0083] In some embodiments, the funnel-shaped outlet is designed and arranged to prevent the formation of a meniscus when a monomer liquid is transferred from the container into the cartridge by free gravitational flow through the funnel-shaped outlet. As explained in more detail elsewhere herein, unobstructed drainage of monomer liquid can be achieved by appropriately selecting the parameters described herein, in particular the angle between the inner surface of the funnel and the longitudinal axis of the inlet tube, the inner diameter of the inlet tube, and the length of the inlet tube. The same parameters also ensure unobstructed drainage of PMMA bone cement powder.

[0084] In some embodiments, the device further comprises a piston for dispensing bone cement from the device. The piston is preferably arranged at least partially within the cartridge and delimits the cartridge to the outside. More preferably, the piston preferably has a releasable locking mechanism. This locking mechanism can be configured, for example, as a pin, tab, or snap-in hook. Other force-fitting or form-fitting connections are also possible. This allows the piston to be releasably connected to the cartridge. The piston can be movably arranged within the cartridge, enabling the discharge of bone cement paste from the cartridge. The feature "movably arranged within the cartridge" does not exclude the presence of a locking mechanism for the piston as described above.Thus, the expression "movably arranged in the cartridge" may also refer to a device in which the piston is only movable in a state of the device in which such a lock is released.

[0085] In some embodiments, the device comprises a mixing rod. The mixing rod is preferably configured for mixing monomer liquid and PMMA bone cement powder. The mixing rod may have blades. The blades may facilitate a homogeneous mixture of monomer liquid and PMMA bone cement powder. The blades are preferably arranged at one end of the mixing rod, which is arranged inside the cartridge. The mixing rod may have one, two, or more than two blades. The mixing rod may have a handle at one end of the mixing rod, which is preferably arranged outside the cartridge.

[0086] The mixing rod can have a dispensing tube. The dispensing tube can be designed and configured to dispense a bone cement paste mixed in the device (i.e., a bone cement paste composed of monomer liquid and PMMA bone cement powder). Preferably, the dispensing tube is closable. This can prevent bone cement paste from undesirably escaping from the cartridge during mixing. The dispensing tube can be configured as a cavity within the mixing rod. In some embodiments, the dispensing tube is closable by a detachable core. Accordingly, the mixing rod can have a detachable, rod-shaped core, for example, a metal core. The core can also improve the strength of the mixing rod.

[0087] The mixing rod can have a predetermined breaking point for breaking it off after the mixing process. The predetermined breaking point is preferably located outside the cartridge so that the mixing rod can be broken off from the outside without opening the cartridge.

[0088] In some embodiments, the container further comprises a carrier for receiving an ampoule. Such ampoule can, in particular, be glass ampoules in which monomer liquid is commercially available. The carrier is preferably arranged and configured to allow the ampoule to be broken open and the monomer liquid to flow out of the ampoule through the outlet and the inlet tube by free gravity flow.

[0089] In some embodiments, the container further comprises a means for opening a foil pouch or a glass ampoule within the device. An example of a means for opening a foil pouch is a spike suitable for piercing a foil pouch. Such a spike can be made, for example, from a rigid plastic or metal. An example of a means for opening a glass ampoule is a projection against which the head of a glass ampoule can be pressed to break it open. A means for opening a glass ampoule can also comprise a flexible housing part so that the glass ampoule can be broken from the outside by hand by deforming the flexible housing part. A means for opening a glass ampoule can also comprise a movably arranged element, such as a piston, which can press the glass ampoule against a hard housing part, e.g. a projection, and thereby break it open.Means for opening a foil bag or a glass ampoule are further disclosed in DE19532015A1, WÖ9718031A1, EP2404864B1 and WÖ2010012114A1.

[0090] In some embodiments, the device is designed and configured to allow venting of the cartridge through the funnel-shaped outlet, while monomer liquid is transferred from the container into the cartridge by free gravity flow via the funnel-shaped outlet and the inlet tube. This means that air can simultaneously flow from the cartridge into the container through the funnel-shaped outlet, while monomer liquid flows from the container into the cartridge.

[0091] This can be achieved in particular by the designs of the funnel-shaped outlet and the inlet tube described herein. Furthermore, the container can have a ventilation opening. The ventilation opening can be designed either as a simple opening or as a valve. The opening can be covered on the inside by a gas-permeable porous material so that the penetration of particles from outside into the container can be prevented, while at the same time an exchange of air through the porous material is possible. The valve can, for example, be designed to only allow air to pass towards the interior of the container. This can improve the transfer of the monomer liquid into the cartridge if the transfer occurs via a pressure difference. In some embodiments, the device can have a connection for a vacuum source to optionally allow a transfer of the monomer liquid via a pressure difference.Such a connection can be arranged, for example, on the cartridge head. In some embodiments, the device is configured to allow transfer of monomer liquid from the container into the cartridge either by free gravitational flow or by a pressure differential.

[0092] A further aspect relates to a kit containing several separate components of the devices described herein. The kit can, for example, have a first element for receiving a monomer liquid and a separate second element for receiving a PMMA bone cement powder. The first element preferably has a container for receiving a monomer liquid, a funnel-shaped outlet, and an inlet tube. The second element preferably has a cartridge for receiving a PMMA bone cement powder. The second element can have a cartridge head arranged at a proximal end of the cartridge. The cartridge head can have an opening to receive the inlet tube of the first element. The first element can be connectable to the second element, preferably detachably connectable. The opening can be reversibly closable, for example by a sliding closure.The sliding closure can be configured to engage a notch in the inlet tube. The kit can include a monomer liquid. The kit can include a PMMA bone cement powder. The kit can include a monomer liquid and a PMMA bone cement powder.

[0093] The first element may contain a monomer liquid. A monomer liquid may also be provided as part of the kit in a separate container, for example, in a foil pouch or a glass ampoule. The second element may contain a PMMA bone cement powder. A PMMA bone cement powder may also be provided as part of the kit in a separate container, for example, in a foil pouch or a plastic container. In some embodiments, the first element contains a monomer liquid, and the second element contains a PMMA bone cement powder. Such devices are also referred to as "fully prepackaged" systems. Preferably, the monomer liquid and PMMA bone cement powder are provided in sterile form. The device is also preferably provided in sterile form.

[0094] A further aspect relates to a method for producing a bone cement, the method comprising the following steps: providing a device according to one of the embodiments described herein; optionally introducing a monomer liquid into the container; optionally introducing a PMMA bone cement powder into the cartridge; optionally allowing the PMMA bone cement powder to flow out of the funnel-shaped outlet and / or from the inlet tube into the cartridge;

[0095] Arranging the device so that the monomer liquid can be transferred from the container into the cartridge by free gravitational flow via the funnel-shaped outlet and the inlet tube;

[0096] Transferring the monomer liquid from the container into the cartridge by free gravitational flow;

[0097] Mixing the monomer liquid with the PMMA bone cement powder in the cartridge to obtain a bone cement.

[0098] The method may, for example, comprise one, several, or all of the following steps: a) providing a device according to one of the embodiments described herein, wherein the device preferably comprises a container, a funnel-shaped outlet, a glass ampoule containing monomer liquid, an inlet tube, a cartridge, a PMMA bone cement powder, a cartridge head, a sliding closure, a mixing rod with a core, an opening in the cartridge head for connection to the inlet tube, a sliding closure, a piston, and a discharge tube; b) orienting the device so that free gravitational flow of the monomer liquid is enabled;c) allowing any PMMA bone cement powder present in the funnel-shaped outlet to flow into an interior of the cartridge, d) releasing monomer liquid in the container, for example by breaking open a glass ampoule containing monomer liquid, e) transferring the monomer liquid from the container into the cartridge by free gravitational flow, preferably with air flowing from the cartridge through the inlet tube into the funnel-shaped outlet at the same time, f) removing the inlet tube from the cartridge, g) closing the cartridge, for example closing the opening in the cartridge head by inserting a sliding closure, h) mixing the monomer liquid with the PMMA bone cement powder using the mixing rod, thereby obtaining a bone cement dough; i) pulling out the core of the mixing rod so that the mixing rod forms a discharge tube;j) squeezing out the bone cement paste by moving the piston towards the cartridge head, and k) expelling the bone cement paste from the device.;

[0099] A further aspect relates to the use of a device according to one of the preceding embodiments or the aforementioned method for producing bone cement, in particular PMMA bone cement. A monomer liquid can be mixed with a PMMA bone cement powder within the device to form a bone cement dough. Such a bone cement dough can be dispensed from the device and hardened into PMMA bone cement at a target location.

[0100] EXAMPLES

[0101] The invention is further illustrated below by examples, which, however, are not to be construed as limiting. It will be apparent to those skilled in the art that other equivalent means may be used in a similar manner instead of the features described here.

[0102] FIGURES

[0103] Figure 1 shows an example of an embodiment of a device 100 described herein. The device 100 has a cartridge 101 configured to hold a PMMA bone cement powder 119. At a proximal end of the cartridge 103, the cartridge has a cartridge head 104. In the example shown here, the cartridge head 104 is designed as a screw cap. The cartridge head 104 has a passage 105 configured to hold a mixing rod 114. The mixing rod 114 has blades 115 disposed within the cartridge 101. The mixing rod can be used to mix a monomer liquid 118 with PMMA bone cement powder 119 to form a bone cement dough 123. The cartridge 101 further comprises a piston 116 which is configured to dispense bone cement dough 123 from the device.The device further comprises a container 102 configured to hold a monomer liquid 118. The container 102 is configured to establish a fluid-conducting connection with the cartridge 103 via a funnel-shaped outlet 108 and an inlet tube 106. For this purpose, the inlet tube 106 can be inserted into an opening 124 of the cartridge head. The funnel-shaped outlet 108 has a funnel inner surface 109, which forms an angle a with a longitudinal axis of the inlet tube 107, which is at most 60°. This enables monomer liquid or PMMA bone cement powder to flow from the container 102 and the funnel-shaped outlet 108 through the inlet tube 106 into the cartridge 101 without the need for mechanical force or a pressure difference. Rather, the drainage of monomer liquid or PMMA bone cement powder can occur by free gravitational flow, ieby the sole effect of gravity. For this purpose, the device can be oriented with the container 102 facing upwards and with the cartridge 101 facing downwards, as shown here. The longitudinal axis of the inlet tube 107 runs in the direction of gravity. In the example shown here, the container 102 further comprises a filter 117 which is permeable to monomer liquid and is arranged at the transition from the container 102 to the funnel-shaped outlet 108. The filter 117 can be designed to prevent contaminants such as glass fragments from entering the cartridge 101. In the example shown here, the container 102 has a carrier for an ampoule 112, for example a glass ampoule. Furthermore, the container 102 here has a projection 111 for breaking open the ampoule 112 by pressing the ampoule head 113 of the ampoule 112 against the projection 111.Furthermore, a ball 110 is arranged in the funnel-shaped outlet 108, which is designed to eliminate PMMA bone cement powder bridges. By moving the ball 110 in the outlet 108, which can be achieved, for example, by gently shaking the device, PMMA bone cement powder bridges can be released, allowing the PMMA bone cement powder to flow from the outlet into the cartridge.

[0104] Figure 2 shows an example of a section of a device according to the invention. A funnel-shaped outlet 108 is directly connected to an inlet pipe 106. An inner surface 109 of the funnel forms an angle a with a longitudinal axis 107 of the inlet pipe, which angle is 60° or less. The inlet pipe 106 has a length L and a diameter i. The ratio L:i of length L to inner diameter i lies in a range from "L:i = 1:10" to "L:i = 1:3.5." The inner diameter i is 4.0 to 10.0 cm.

[0105] Figure 3 shows an example of an embodiment of a device according to the invention. In the example shown here, the container 102 has a carrier for a glass ampoule 112 containing a monomer liquid 118. A PMMA bone cement powder 119 is arranged in the cartridge 101. The inlet tube 106 projects only far enough into the cartridge 101 that it does not touch the PMMA bone cement powder 119 when the device is arranged upright as shown here. Figure 4 shows an example of a device according to Figure 3, wherein the monomer liquid 118 has been released from the glass ampoule. The monomer liquid 118 is transferred by free gravitational flow from the container 102 via the funnel-shaped outlet 108 and the inlet tube 106 into the cartridge 101. In the cartridge, the monomer liquid 118 comes into contact with PMMA bone cement powder 119.For mixing monomer liquid 118 and PMMA bone cement powder 119, the device has a mixing rod 114 that partially extends into the cartridge 101 and has vanes 115. The vanes 115 can enable homogeneous and effective mixing of monomer liquid 118 and PMMA bone cement powder 119. The mixing rod 114 also has a metal core that closes a cavity inside the mixing rod. By removing the metal core, the cavity can be exposed, so that the cavity of the mixing rod can be used to dispense bone cement dough from the device. Furthermore, the metal core can improve the stability of the mixing rod, thus achieving improved force transmission during movement of the mixing rod.

[0106] Figure 5 shows, by way of example, a device according to Figure 3 or Figure 4, wherein the container 102 is no longer fluidically connected to the cartridge 101. In the configuration shown here, the inlet tube 106 is pulled out of the opening 124 of the cartridge 101. The opening 124 can be closed by a closure 120. The closure 120 is designed here as a sliding closure that can be inserted laterally over the opening 124. In the example shown here, the sliding closure 124 is configured to engage in the cartridge head 104 when closed, such that the sliding closure cannot open automatically in the closed state. This can be achieved by a suitable locking mechanism on the cartridge head. By separating the cartridge 101 from the container 102, improved handling of the cartridge 101 can be achieved when mixing monomer liquid with PMMA bone cement powder.

[0107] Figure 6 shows an example of a device according to the invention containing a bone cement paste made of monomer liquid and PMMA bone cement powder. In this example, the device has a threaded rod 122, the thread of which engages the cartridge head 104. The threaded rod 122 is configured to move a piston 116 movably arranged in the cartridge 101 in order to dispense bone cement paste 123 from the device via a discharge tube 121. LIST OF REFERENCE SYMBOLS

[0108] 100 device

[0109] 101 cartridge

[0110] 102 containers

[0111] 103 Proximal end of the cartridge

[0112] 104 cartridge head

[0113] 105 Implementation

[0114] 106 Inlet pipe

[0115] 107 Longitudinal axis of the inlet pipe

[0116] 108 Funnel-shaped outlet

[0117] 109 Funnel inner surface

[0118] 110 Agents for the elimination of PMMA bone cement powder bridges

[0119] 111 lead

[0120] 112 ampoules

[0121] 113 Ampoule head

[0122] 114 mixing rod

[0123] 115 wings

[0124] 116 pistons

[0125] 117 filters

[0126] 118 Monomer liquid

[0127] 119 PMMA bone cement powder

[0128] 120 closure

[0129] 121 Discharge pipe

[0130] 122 threaded rod

[0131] 123 Bone cement dough

[0132] 124 Opening

Claims

CLAIMS 1. A device for mixing bone cement, comprising a cartridge (101) for holding a PMMA bone cement powder; a container (102) for holding a monomer liquid (118), the container being fluidly connected to the cartridge (101); a cartridge head (104) arranged at a proximal end (103) of the cartridge, the cartridge head having a passage (105); an inlet tube (106), the inlet tube having a longitudinal axis (107); and a funnel-shaped outlet (108), the funnel-shaped outlet having a funnel-shaped inner surface (109) which is at least partially arranged at an angle (α) of no more than 60° to the longitudinal axis (107) of the inlet tube (106); wherein the device is designed and arranged to transfer a monomer liquid from the container into the cartridge by free gravitational flow via the funnel-shaped outlet and the inlet tube.

2. Device according to claim 1, wherein the inlet pipe (106) has an inner diameter i of 4.0 mm to 10.0 mm.

3. Device according to one of the preceding claims, wherein the inlet pipe (106) has a length L and an inner diameter i, and wherein the ratio L : i of length L to inner diameter i is in a range from "L : i = 1 : 10" to "L : i = 1 : 3.5".

4. Device according to one of the preceding claims, wherein the funnel-shaped outlet (108) is further designed and arranged to allow a PMMA bone cement powder to flow out into the cartridge (101) by free gravitational flow.

5. Device according to one of the preceding claims, which further comprises a means (110) for eliminating PMMA bone cement powder bridges in the outlet (108), wherein the means for eliminating PMMA bone cement powder bridges is preferably a sphere, wherein the sphere is further preferably arranged to be movable in the funnel-shaped outlet.

6. Device according to one of the preceding claims, wherein the funnel inner surface (109) forms an angle a of not more than 60° over at least 50% of its total area, preferably not more than 55°, more preferably an angle of 21° to 50°, to the longitudinal axis (107) of the inlet pipe (106).

7. Device according to one of the preceding claims, wherein the cartridge comprises a PMMA bone cement powder, and / or wherein the container comprises a monomer liquid of a bone cement.

8. Device according to one of the preceding claims, wherein the funnel-shaped outlet (108) has a tapered end which is directly connected to the inlet pipe (106) in a fluid-conducting manner.

9. Device according to one of the preceding claims, wherein the container further comprises a filter (117) permeable to a monomer liquid, wherein the filter is preferably arranged and configured to prevent penetration of glass splinters from the container into the cartridge, and wherein the filter preferably has a surface area of ​​at least 5 cm on one side of the filter 2 , further preferably at least 10 cm 2 , even more preferably 15 cm 2 has.

10. Device according to one of the preceding claims, wherein an interior of the funnel-shaped outlet and an interior of the cartridge together form a continuous cavity.

11. Device according to one of the preceding claims, wherein the funnel-shaped outlet is designed and arranged to prevent the formation of a meniscus when a monomer liquid is transferred from the container by free gravitational flow via the funnel-shaped outlet into the cartridge.

12. Device according to one of the preceding claims, further comprising a piston (116) for dispensing bone cement from the device, wherein the piston is arranged at least partially in the cartridge and outwardly delimits the cartridge, and wherein the piston preferably has a releasable lock.

13. Device according to one of the preceding claims, further comprising a mixing rod (114), wherein the mixing rod preferably has a closable discharge tube, wherein the discharge tube is preferably designed and configured to discharge a bone cement dough mixed in the device from the device.

14. A device according to any one of the preceding claims, wherein the container further comprises a carrier for receiving an ampoule.

15. A device according to any one of the preceding claims, wherein the container further comprises means (111) for opening a foil bag or a glass ampoule within the device.

16. Device according to one of the preceding claims, wherein the device is designed and arranged to enable venting of the cartridge through the funnel-shaped outlet while a monomer liquid is transferred from the container into the cartridge by free gravitational flow via the funnel-shaped outlet and the inlet tube.

17. A method for producing a bone cement dough, the method comprising the following steps: Providing a device according to any one of the preceding claims; optionally introducing a monomer liquid into the container; optionally introducing a PMMA bone cement powder into the cartridge; optionally allowing the PMMA bone cement powder to flow out of the funnel-shaped outlet and out of the inlet tube into the cartridge; Arranging the device so that the monomer liquid can be transferred from the container into the cartridge by free gravitational flow via the funnel-shaped outlet and the inlet tube; Transferring the monomer liquid from the container into the cartridge by free gravitational flow; Mixing the monomer liquid with the PMMA bone cement powder in the cartridge to obtain a bone cement dough.

18. Use of a device according to any one of claims 1 to 16 or a method according to claim 17 for producing bone cement dough.

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