WO2009048366A1

WO2009048366A1 - Mixing system and mixing method for medical purposes

Info

Publication number: WO2009048366A1
Application number: PCT/SE2008/000552
Authority: WO
Inventors: Erik Johansson; Niklas Axen; Staffan Bowald; Sven Olerud; Hans Jacobsen
Original assignee: Ortoviva Ab
Priority date: 2007-10-10
Filing date: 2008-10-10
Publication date: 2009-04-16
Also published as: AU2008311495B2; EP2207519A4; SE0702267L; JP2011500134A; EP2207519A1; AU2008311495A1; US8267571B2; CA2701174C; KR20100098598A; CA2701174A1; SE531600C2; US20090266420A1; EP2207519B1

Abstract

A system and a method for achieving an injectable mixture for medical purpose starting out from at least one first pulverulent component (2) and a second liquid component (13) with a first piston/cylinder arrangement (1) with a cylinder (22) with an axial extension and a piston (20), wherein the cylinder includes a measured amount of the pulverulent component (2), a separate reservoir (12) including a corresponding measured amount of the liquid component (13), and means for sealed transfer of said amount of the liquid component to the cylinder for subsequent mixing and injection of the completed mixture. The first piston/cylinder arrangement is a (first) injection syringe (1). A mixing element (4) being manoeuvrable of a user is positioned inside the cylinder. At least one gas transferring channel means leading to the cylinder is arranged at the cylinder. Engagement means (8',18) are arranged for connecting the first injection syringe (1) to the separate reservoir (12) during transfer of the liquid component.

Description

MIXING SYSTEM AND MIXING METHOD FOR MEDICAL PURPOSES

FIELD OF THE INVENTION

The invention concerns a system for achieving a mixture for medical purposes that can be injected in accordance with the preamble of claim 1 and a method according to the preamble of claim 16.

BACKGROUND OF THE INVENTION It is previously known to introduce different paste-like materials into the human body for medical and in particularly orthopaedic purposes. It is hereby usually materials often called bone cements and bone replacement materials or "bone grafts". These can be of different types, for example based on synthetic or ceramic material and be used for filling voids in bone tissue or for supporting fastening of implants on bone tissue .

A known bone replacement material or bone cement is based on settable synthetic material, in particular an acrylic plastic - polymethylmetacrylate (PMMA) , which is commonly used in different orthopaedic applications. Traditionally bone cement is used in hip joints and in knee joints but lately also for filling voids in vertebrae, in wrists and more applications. Characterizing for bone cement is that it is a two-component material wherein the starting materials are comprised of one pulverulent component and one liquid component, which have to be thoroughly mixed in accurately measured amounts for obtaining a good result.

It is known that the hardening is relatively fast and during heat release, which later escalates the hardening process, which is the reason that it is important that the process of mixing and application of the bone cement is relatively fast in order not to jeopardise quality of the result .

At present mixing is often undertaken by providing measured amounts of the two components into a mixing bowl wherein mixing is obtained through manual agitation. Thereupon the mixture is transferred over a funnel and a supply pipe to an injection device including a piston cylinder unit.

In respect of this technology, strict requirements for sterility of the bone cement can be difficult to withhold during such preparation. Toxic vapours resulting from the components also are a risk factor for a person handling the material .

In another common arrangement, pulverulent and liquid components are provided separately to a mixing device wherein a mechanical mixer provides the agitation.

As background art can be mentioned US 5 435 645 and WO 2005/053581.

CHARACTERIZING FEATURES AND MOST IMPORTANT AIMS OF THE INVENTION

It is an aim of the present invention to provide a system and a method as above which address above problems in the direction of at least mitigating them.

This is achieved in respect of the system according to above through the features of the characterizing portion of claim 1.

Hereby is achieved that a system is created which is simple to handle for a user, and which is suitable for larger as well as very small mixture amounts, for example very small amounts of bone cement, as example about 1 - 20 ml, for precision application in narrow cavities in connection with open surgery as well as minimal -invasive surgery. The system is, however, also suitable for use in respect of greater amounts of bone cement as well as other types of mixtures for medical purposes. By providing a mixing element ensures the possibility of adequate and thorough mixing and thereby high quality of the mixture. By providing a gas transferring channel means, a possibility is obtained on the one hand for de-aerating the completed mixture, on the other hand to supply a sterilizing gas to the pulverulent component. The first injection syringe and the separate reservoir can be connected or "be docked" in connection with the transfer of the liquid component. Hereby is guaranteed that the closed transfer is safe and according to high hygienic requirements at the same time as the different components, the first injection syringe and the second piston/cylinder arrangement, can be handled separately and be treated in such ways that are suitable for the different components.

Hereby can be mentioned that the two components of some bone cements, such as for example today's PMMA based cement, can not be sterilized with the same method, because one method which is suitable for the one component can be ineffective or harmful for the other component. For that reason it is important that a system that can be used for a plurality of different cements on the market has separate containers for the different component so that the system gives the possibility of applying different sterilizing methods when used for bone cements where it is necessary.

Concerning bone cements of the mentioned kind, the liquid component has generally one commercially and technically applied sterilizing method which is aseptic filling over a sterile filter. The pulverulent component can be gas sterilized (ETO) or be sterilized through radiation. During gas sterilization, a pulverulent component which is prefilled and inside a package for a packed syringe inside a package of a material which is permeable to the sterilizing gas but micro biologically tight is subjected to an atmosphere with this sterilizing gas. The gas can thus penetrate a package material, reach the syringe and subsequently reach and sterilize the pulverulent component through the gas transferring channel means. In practice, the packaged syringe is put inside a kind of a gas vessel, wherein for example is created an under-pressure, whereupon supplied sterilizing gas is sucked into the syringe and thereby the pulverulent component over said gas transferring channel means. After completed gas treatment, the gas is sucked out from the package over the same channel means and through the package material .

By the gas transferring channel means being displaceable arranged inside the cylinder and in particular a mouth of the gas transferring channel means being displaceable in the axial direction of the cylinder, very effective de-aerating of the mixture after completed mixing is possible. During mixing, air enclosures are created inside the mixture, which could seriously deteriorate the quality of the mixture/the bone cement or the like. Bone cement is namely often relatively highly viscous and air enclosures can therefore not simply be shaken or pressed out in an effective manner. Through this aspect of the invention, however, a gas transferring channel means can be brought to "search" for these air enclosures through its displacement inside the cylinder, normally during simultaneous activation of the first injection syringe, such that a minor over-pressure prevails therein. Considerably more effective de-aeration of the complete mixture body can therefore be achieved through the invention.

The invention is particularly suited for preparing paste- like mixtures, wherein it's usual that the air enclosures remain in the completed paste. The invention has, however, also its application for other mixtures wherein air bubbles easily become more permanently remaining after completed mixing procedure. It can be in respect of somewhat jelly-like or syrupy mixtures. By the separate reservoir being included in a second piston/cylinder arrangement and in particular in a second injection syringe, standard components can be used, which are easy to handle and economically advantageous. Through this arrangement it is possible to introduce a very precise amount of the liquid component into the cylinder such that high quality can be reached for the mixture.

By the second engagement means being releasable, the first injection syringe can be freed from the second piston cylinder arrangement after completed transfer of liquid component for further handling of the completed mixture. It is rational and preferred that a means for manoeuvring the mixing element also includes said gas transferring means. Hereby it is achieved in a simple manner that these functions are integrated and hereby the possibility of de-aerating according to the above is simplified.

It is preferred also that said gas transferring channel means is comprised of a transfer channel means for transferring the liquid component from the second piston/cylinder arrangement, whereby further integration of different functions into the system is achieved.

It is also preferred that a means for manoeuvring the mixing element includes said transfer channel means .

In the cases where the first and at occasions the second injection syringe are single use articles the problems with cleaning and reuse of these details are avoided and in case they are comprised of standard components, an economically advantageous solution is obtained. It is thus preferred that the system is adapted for use in connection with the application of bone cement into a patient, but also use within other medical applications are envisaged such as for medical mixtures with the property that they bind air enclosures and therefore should be de-aerated before being administered.

The corresponding advantages are obtained in respect of a method according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention shall now be described in more detail by way of embodiments and with reference to the annexed drawings, wherein :

Fig. la-c show different step for filling and sterilizing of a pulverulent component into a first injection syringe.

Fig. id shows a free holder means in the form a needle shaped element,

Fig. 2a and 2b show two steps in connection with filling of a liquid component into a second injection syringe, Fig. 3a-f show different steps in connection with mixing of components before application of the mixture,

Fig. 4a-c show a somewhat modified first injection syringe in different views,

Fig. 5a and b show filling of a somewhat modified second injection syringe,

Fig. 5c shows in an enlarged scale an adapter for filling,

Fig. 6 shows the modified first injection syringe docked to the modified second injection syringe, Fig. 7 shows a injection needle for use with a system according to the invention, and

Fig. 8 shows the modified first injection syringe in connection with associated components. DESCRIPTION OF EMBODIMENTS

Like and similar elements in the different embodiments have been given same reference numerals.

With reference to Fig. Ia - Ic the process of sterilizing a pulverulent component 2 inside the first injection syringe 1 is shown. In Fig. Ia is diagrammatically shown a first filling station, whereby a dosing and filling device 3 is arranged to deliver a measured amount of the pulverulent component 2, which falls down into a cylinder 2 of the first injection syringe 1.

This first injection syringe is in shown station also provided with a mixing element 4 which is connected to a manoeuvring means 7 - 8 for making it possible to rotate the mixing element and to make it possible to displace it in axial direction of the cylinder during a later mixing operation.

A tubular portion 7 of the manoeuvring means 7 - 8 having an inside channel extends from the mixing element 4 through a (not shown) passage in a connection portion 5, to a first engagement means in the form of an outside thread outermost on a rotation portion 8. The connection portion 5 has outermost a (not shown) outer male thread for later application of a chosen injection needle when the completed mixture is to be inj ected.

From Fig. Id is shown a free holding means 28 in the form of a needle-shaped element 30, which is rigidly connected to a fastening element in the form of a sleeve shaped element 29, which has means such as inside female threads 29' for cooperation with corresponding fastening means such as the above mentioned male threads on the connection portion 5. Also other fastening principals can be envisaged such as bayonet connection means.

The aim of the free holding means 28 is that after filling with pulverulent component and until the point where mixing of the two components is to be made, prevent that the pulverulent component penetrates into the channel inside the tubular portion 7, which otherwise could risk blocking the later for gas transfer and later transferring of a liquid component. In the embodiment shown in Fig. Id, the needle- shaped element 30 of the free holding means 28 is hollow all over its length and together with the sleeve shaped element 29, which has a recess 31, there is formed a gas penetrable connection through the free holding means 28 such that gas can penetrate from the outside to the inside of the first injection syringe for sterilizing purposes. Certain gas transfer can also be had between the envelop surface of the needle shaped element 30 and the channel wall of the tubular portion 7. In Fig. Ib is known in a second station that a piston 20 with a piston rod 21 for its manoeuvring is introduced into the free end of the cylinder of the injection syringe 1, which is filled with pulverulent component 2 for forming of a first piston/cylinder arrangement. In Fig. Ic is shown in a third station the first injection syringe 1, filled with pulverulent component, placed in a chamber 9, which is arranged from a gas container 10 over a gas conduit 11 to feed a sterilizing gas into the chamber enclosing a package with the first injection syringe 1. With reference to the above, sterilizing gas can thus penetrate into the inside of the first injection syringe 1 over, to start with, the recess 31. After completed sterilization, the first injection syringe is ready for delivery/use. It should be noted that other solutions for achieving gas transfer is within the scope of the invention such as for example that all gas transfer is between an envelope surface of a non hollow needle-shaped element 30 and the channel wall of the tubular portion 7. Also other per se known sterilizing methods for different uses of the invention are within the scope of the invention. It is thus possible to use radiation sterilization with ionizing radiation or for example certain electro magnetic radiation with sufficient power for the purpose. It is also possible to use heating in dry heat or dry heat atmosphere in certain instances.

In Fig. 2a is shown a first station for filling a liquid component 13 into a second injection syringe 12. Hereby is in a corresponding manner as during filling of the first injection syringe 1, the second injection syringe 12 arranged for receiving a measured amount of the liquid component 13 contained inside a supply 16 over a feed pump 15, which is arranged to provide the inside of the second injection syringe 12 with said measured amount of the liquid component over a liquid conduit 17 and a sterile filter 14.

On the lower part of the second injection syringe, as shown in Fig. 2a, is arranged a closure 19 with second engagement means 18 in the form of a (not shown) inner thread or the like.

In Fig. 2b is shown in a second station that the filled second injection syringe 12 has been provided with the piston 23 with associated piston rod 24 for manoeuvring of the piston. After completed sterilization outside with a sterilizing gas, possibly when being packaged inside a gas penetrable plastic bag (not shown) the second injection syringe is ready for delivery/use.

It should be mentioned that other sterilizing methods for the liquid component are within the scope of the invention. Thus, depending on the material to sterilize, other per se known methods can be used such as radiation, sterilization with ionizing radiation or for example certain electromagnetic radiation with sufficient power for the application. Also for example autoclaving in moist heat can be used for certain applications .

In Fig. 3a - f are shown a sequence for conducting the mixing of the two components for achieving of an injectable mixture of, in the shown example, bone cement.

Fig. 3a shows the first 1 and the second 12 injection syringe taken out from their sterile packages and prepared for being connected through the first and second engagement means 8' and 18, respectively. These are here in the form of an outside thread 8' outermost at the rotational portion 8 as concerns the first injection syringe 1 and said inner thread at 18 as concerns the second injection syringe 12. The free holding means 28 shown in Fig. Id has already been removed from the first injection syringe 1 and left the channel inside the manoeuvring means 7 - 8 open for introduction of the liquid component.

In Fig. 3b is shown the second injection syringe connected or docked to the first injection syringe. In Fig. 3c the process is illustrated with feeding of the liquid component from the second, 12, to the first, 1, injection syringe through pressing-in of the piston 23.

In Fig. 3d is shown the very mixing process, wherein the mixing element 4 is rotated at the same time as it is moved in axial direction of the cylinder 22 through actuation of the manoeuvring means 7 - 8. At the end of this process, the mixture is de-aerated by a minor pressure being applied to the piston 20 over the piston rod 21 in order to create a minor over-pressure inside the cylinder at the same time as the manoeuvring means 7 - 8 (with connected mixing element 4) is moved for movement in axial direction. During this important step of the method according to the invention, the completed mixture, which is put somewhat on over-pressure, is effectively de-aerated by gas enclosures in the mixture being "searched" by a mouth 24 to a de-aerating channel, which in this case is the said channel inside the tubular manoeuvring means 7 - 8. The de-aerating channel can also have more than one mouth 25, for example two on opposite sides of the tubular manoeuvring means. Since the second injection syringe 12 is still connected to the first injection syringe, captured, in many cases harmful gases, will be received inside the second injection syringe 12 such that they will not reach the operators respiratory organs. In Fig. 3e is shown that after completed mixing, the manoeuvring means 7, 8 for the mixing element 4 is released by simply pulling out the manoeuvring means 7 - 8 entirely axially from the first injection syringe.

It should been noted that in real life operation, the mixing element 4 can be invisible in some of the sequence steps above because of obscuring (bone cement) mixture. It is, however, for clarity shown throughout the Figures.

After that, as is shown on Fig. 3f, a. chosen injection needle 26 is applied on the first injection syringe 1, in this case with a connected finger grip 27, whereupon the first injection syringe is ready for application of bone cement.

In a second embodiment, which is shown in Figs. 4 - 8 the system is somewhat modified. The first injection syringe 1, which is shown in Fig. 4a, is provided with a mixing element 4 with a plurality of, here four, mixing wings 4' in the direction of the outlet of the syringe and, in the opposite direction, a plurality of, here four, pins 4" for providing a good mixing of the components. The detail 4"' is a ring-shaped stabilizing element, which defines axial through openings for allowing the mixing components easily to pass through the mixing element 4 during axial movements thereof. In the outlet end of the cylinder 22 is arranged a wiper plate 32, which tightly lies against the tubular portion of the manoeuvring means 7 for the purpose of wiping off in particular pulverulent component from this tubular portion when it is pulled in and out from the cylinder 22. Hereby is avoided that the pulverulent material will reach out into the area of the outlet of the injection syringe 1 and not being part of the mixing. Pulverulent material in this region would also unnecessarily increase friction between the tubular portion of the manoeuvring means and the syringe in this area.

In Fig. 4b is shown at the piston rod side of the first injection syringe, a first grip 44, which is rigidly fastenable to the syringe, and which has the function of facilitating handling, through a lock washer 46, which can be snapped into a recess in the first grip 44 with radially outside extending wings (shown with full lines on the Figure) , whereby the locking washer 46 lies in axial direction against an end flange 45 on the first injection syringe.

The first grip 44 has a portion at 50 for lying against a second side of this end flange 45. The locking washer 46 further has portions (not shown) which are radially extending inwardly inside the section of the cylinder 22, such that they act like a stop and prevent the piston of the first injection syringe 1 to come out from the cylinder. 8 indicates a rotational portion for a manoeuvring means for the mixing element 4. In Fig. 4c is shown the first injection syringe 1 with removed free holding means 28 corresponding to what is described above in respect of the first embodiment.

In Fig. 5a is shown an arrangement for filling the second injection syringe 12, wherein it is docked to a first side of an adapter 33, which on its other side, in a vial docking space, is arranged to receive a vial 34 with the liquid component. It is further shown on Fig. 5a a second grip 35 for the second injection syringe 12, which grip in an axial direction from an outlet end towards a piston rod end lies against an end flange 51 (Fig. 5b) . The second grip 35 has a stop 36, which outermost on the piston end side has a hook means 37 for engagement with an end side of a piston rod which is introducible into the second injection syringe 12. The purpose of the this stop 36 is to avoid that during later use of the second injection syringe 12, the piston contained therein is moved axially outwardly because of arising overpressure, which is explained below.

In Fig. 5b is shown a second through the arrangement in Fig. 5a, wherein the vial 34 is shown with an opening 39 after braking away of an enclosure end. With 38 is indicated a sealing/holding ring for ensuring holding of the vial sealingly in position inside the adapter 33. The adapter 33 further has a liquid filter 40 for filtering away of impurities such as for example glass particles resulting from breaking of the opening end of the vial. Further, the adapter 33 has a venting channel with a venting pipe 42, which is arranged to be introduced somewhat into the vial in its applied position. An air filter 41 is arranged in the venting channel for ensuring sterility of the air provided through the venting channel.

When using the adapter, the stop 36 is released such that the second injection syringe 12 can be filled by axial pulling out of the piston in per se known manner until a predetermined amount of the liquid component contained in the vial 34 has been drawn into the second injection syringe. Thereupon, the second injection syringe is released from the adapter 33 preferably by screwing out of a threaded connection there between. In Fig. 5c is further shown the adapter 33 more clearly, freed from the vial and from the second injection syringe. At the side of docking with a second injection syringe, is preferably arranged a thread (not shown) for secure mutual connection of these components. In Fig. 6 is shown the two injection syringes 1 and 12 docked to each other prior to feeding of the liquid component from the second injection syringe 12 to the first injection syringe 1. Hereby a piston rod of the second injection syringe 12 is thus pressed axially inwardly until it is locked by the axial stop 36 as is indicated above. During this inward pressure, an over-pressure will result in the connected unit, which would otherwise easily lead to a certain amount of liquid being fed back if the piston 23 would be allowed to move axially from the most inward position. This could give an erroneous mixing relation between the components and inferior properties of the mixture. In Fig. 7 is shown an injection needle unit with an injection needle 26 for driving into bone as for example a vertebra of a patient, into which bone cement is to be injected. The injection needle 26 is shown with an insert point, which has good properties for allowing driving- in of the unit. 27 indicate a finger grip for the unit and 49 a press portion, with the aid of which the unit is applied and guided. In connection with the driving- in, the unit could be subjected to minor strikes in a driving direction, which most simply is conducted by removing the press portion 49 and application of strikes against a particular strike receiving element which can be screwed- in to the upper end of the unit. In Fig. 8 is shown the first injection syringe 1 in connection with on the one hand the manoeuvring means 7, 8 for the mixing element 4 and the free holding means 28 which is introducible their inside, on the other hand with the injection needle unit with the injection needle 26 and removed insert point 48 as well as removed press portion 39. The manoeuvring means is shown with threads for engagement with the mixing element 4 but also other releasable connection can be used such as axial ridges in engagement with the grooves. The invention can be modified within the scope of the following claims. The filling of the pulverulent and the liquid component respectively can thus be made differently, even manually, even if automatic filling is preferred. Further, the docking means/engagement means can be constructed differently and gas transferring channels can be arranged differently from what is shown in Fig. Ia - c . The gas transferring channel means for de-aerating can be separated from the shown manoeuvring means 7 - 8 for the mixing element, but it is highly preferred that these elements are integrated for simple function and good economy.

The separate reservoir is preferably included, which is described above, in a second piston cylinder arrangement and preferably it is in form of an injection needle. It is, however, also within the scope of the invention, that the separate reservoir is of a different construction, for example a breakable ampoule or without means for pressurising the liquid component. In one embodiment the separate reservoir, which can be or include such an ampoule, is on one side possible to dock to the first injection syringe and on a second side connected or connectable to a piston cylinder device or any other pressure creating device for driving purposes, whereby can be created an over-pressure such that the liquid component can be introduced into the first cylinder of the first injection syringe. In a further embodiment can be provided an under-pressure in the cylinder of the first injection syringe, whereby can be initiated that the liquid component can be sucked into this cylinder.

The invention can be used in respect of other mixtures for medical purposes but is particular preferred in more highly viscous or paste-like mixtures such as bone replacement material - bone cement, even if it is not excluded that the invention is also applicable in more low viscous mixtures with the property of binding air enclosures and therefore should be de-aerated.

For other mixtures that can come into question for the using of a system according to the invention, other sterilizing methods than the above described can come into question. A pulverulent component can for example be sterilized in dry hot atmosphere and a liquid in moist hot atmosphere .

The invention can be modified further and one example of that is that it can be given an indication on when the mixture is completed and as an example also has reached a certain viscosity by using a coupling between the manoeuvring means and the mixing element, which releases from rotation at reaching a certain viscosity and corresponding rotational resistant of the mixture.

Claims

C L A I M S

1. System for achieving an injectable paste-like mixture for medical purpose starting out from at least one first pulverulent component (2) and a second liquid component (13) , wherein the system includes :

- a first piston/cylinder arrangement (1) with a cylinder (22) with an axial extension and a piston (20) , wherein the cylinder includes a measured amount of the pulverulent component (2) ,

- a separate reservoir (12) including a corresponding measured amount of the liquid component (13) , and

- means for sealed transfer of said amount of the liquid component to the cylinder for subsequent mixing and injection of the completed mixture, c h a r a c t e r i z e d in

- that the first piston/cylinder arrangement is a (first) injection syringe (1),

- that a mixing element (4) being manoeuvrable of a user is positioned inside the cylinder, - that at least one gas transferring channel means leading to the cylinder is arranged at the cylinder,

- that said gas transferring channel means is arranged displaceably in the cylinder, and

- that engagement means (8', 18) are arranged for connecting the first injection syringe (1) to the separate reservoir (12) during transfer of the liquid component.

2. System according to claim 1, c h a r a c t e r i z e d in that a mouth of said gas transferring channel means inside the cylinder is displaceable in the axial direction of the cylinder for the aerating purposes.

3. System according to claim I or 2, c h a r a c t e r i z - e d in that the separate reservoir is included in a second piston/cylinder arrangement (12) preferably in the form of a second injection syringe (12) .

4. System according to claim 3, c h a r a c t e r i z e d in that the second injection syringe (12) has a stop (36) for preventing of axial movement of an associated piston in the cylinder.

5. System according to claim 3 or 4, c h a r a c t e r i z e d by an adapter (33) with a first side for connection of the second injection syringe (12) and a second side for connection of a liquid containing vial for transfer of the liquid component from the vial over the adapter to the second injection syringe (12) .

6. System according to claim 5, c h a r a c t e r i z e d in that the adapter (33) is provided with a liquid filter (40) for filtering away of impurities during transfer of liquid component.

7. System according to claim 5 or 6, c h a r a c t e r i z e d in that the adapter (33) has a venting channel with an air filter (41) arranged in the venting channel for ensuring sterility of air brought in through the venting channel during transfer of liquid component.

8. System according to any one of the previous claims, c h a r a c t e r i z e d in that said engagement means (8', 18) are releasable.

9. System according to any one of the previous claims, c h a r a c t e r i z e d in that a means (7,8) for manoeuvring of the mixing element (4) includes said gas transferring channel means.

10. System according to any one of the previous claims, c h a r a c t e r i z e d in that said gas transferring channel means is comprised of transfer channel means for transferring the liquid component from the separate container.

11. System according to claim 9, c h a r a c t e r i z e d in that the means (7,8) for manoeuvring of the mixing element (4) includes said transfer channel means.

12. System according to any one of the previous claims, c h a r a c t e r i z e d in that the first injection syringe includes a wiping plate acting against the means (7,8) for manoeuvring the mixing element (4) .

13. System according to any one of the previous claims, c h a r a c t e r i z e d in that the first and at occurrences the second injection syringe is one or two of the group: single use article and standard component.

14. System according to any one of the previous claims, c h a r a c t e r i z e d in that the mixture is anyone from the group: a bone replacement material, a bone cement, a medical .

15. System according to any one of the previous claims, c h a r a c t e r i z e d in that the first injection syringe (1) has a stop (46) for preventing an associated piston to move out from the cylinder.

16. Method for achieving an injectable mixture for medical purposes starting out from at least one first pulverulent component and one liquid component (13) , wherein:

- a first piston/cylinder arrangement (1) with a cylinder with an axial extension and a piston is supplied with a measured amount of the pulverulent component,

- a separate reservoir is supplied with a corresponding measured amount of the liquid component (13), and

- said amount of the liquid component is sealingly transferred to the cylinder for subsequent mixing and injection of the completed mixture , c h a r a c t e r i z e d in

- that the pulverulent component (2) is supplied to the first piston/system arrangement which is a (first) injection syringe

(D, - that the liquid component (13) is supplied to the separate reservoir for introduction therefrom to the cylinder,

- that the components are mixed inside the cylinder by means of a mixing element (4) being manoeuvrable by a user,

- that the mixture is de-aerated through at least one gas transferring channel means which is leading to the cylinder and arranged at the cylinder,

- that said gas transferring channel means is displaced inside the cylinder during de-aeration, and

- that the first injection syringe and the separate reservoir through engagement means are interconnected for the transfer of the liquid component.

17. Method according to claim 15, c h a r a c t e r i z e d in that a mouth of said gas transferring channel means is displaced in the axial direction of the cylinder during de- aeration.

18. Method according to claim 16 or 17, c h a r a c t e r i z e d in that the liquid component (13) is supplied and pressed into the cylinder through a second piston/cylinder arrangement, preferably in the form of a second injection syringe (12).

19. Method according to any one of the claims 16 - 18, c h a r a c t e r i z e d in that the separate reservoir (12) and the first injection syringe (1) are realisably interconnected for transfer of the liquid component (13) .

20. Method according to any one of the claims 16 - 19, c h a r a c t e r i z e d in that the mixture is any one from the group: a bone replacement material, a bone cement, a medical .

21. Method according to any one of the claims 16 - 20, c h a r a c t e r i z e d in that the pulverulent component before mixing is sterilized through any one from the group: a sterilizing gas supplied through said gas transferring channel means, radiation, dry heat.

22. Method according to any one of the claims 16 - 21, c h a r a c t e r i z e d in that the liquid component before mixing is sterilized through any one from the group: aseptic filling over a sterile filter, autoclaving (moist heat) , radiation sterilization.

23. Method according to any one of the claims 16 - 21, c h a r a c t e r i z e d in that the liquid component over an adapter (33) is transferred from a vial to a second injection syringe (12) defining the separate reservoir.