Abstract:
A device for the impregnation of a porous bone replacement material with an impregnation agent includes a container with a central axis and a cavity with a lid. The container has two sealable openings and elastic means. The elastic means are arranged in the cavity allowing a clamping force to be exerted on a bone replacement material inserted in the cavity. A single size container is sufficient for housing variously sized implants, where the implant placed in the cavity of the container is held, centered and protected against damage or breakage, for example, by shaking back and forth or during transportation of the container.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application is a continuation of International Patent Application No. PCT/CH2004/000335, filed on Jun. 3, 2004, the entire contents of which is expressly incorporated herein by reference. 
     
    
     TECHNICAL FIELD  
       [0002]     The invention refers to a device for impregnating a porous bone replacement material.  
       BACKGROUND OF THE INVENTION  
       [0003]     A device for impregnating a porous, biocompatible bone replacement material is already known from U.S. Pat. No. 6,049,026 to MUSCHLER. This known device comprises a chamber for receiving the bone replacement body as well as a first container above the chamber, for storing an impregnation agent and a second container below the chamber for receiving the impregnation agent flowing through the chamber with the bone replacement body. When opening a first valve set between the first container and the chamber, the impregnation agent flows into the chamber with the bone replacement body. As soon as the chamber is filled, a second valve set between the chamber and the second container opens, so that the impregnation agent can flow into the second container through a membrane arranged below the bone replacement body. A disadvantage of this known device is that the bone replacement body in the chamber cannot be clamped down in the chamber, so that the bone replacement material or implant can, for instance by shaking back and forth during transport, be damaged or broken.  
       SUMMARY OF THE INVENTION  
       [0004]     The present invention provides a remedy for the above-discussed disadvantage. It is an object of the invention to produce or create a device for impregnating a porous bone replacement material whereby an implant, for example, a body made of bone replacement material, can be secured against damage by shaking back and forth, for instance during transport.  
         [0005]     In a preferred embodiment the device for impregnating a porous bone replacement material has a container, having a central axis, including a cavity and a lid. The container is included with two openings fitted with a lock, and comprises elastic means arranged inside the cavity, whereby a bone replacement material introduced into the cavity is subjected to a clamping force. Advantages gained by the device acc are: 
        a single container size suffices for receiving variously sized implants in the same, and     an implant inserted into the cavity of the container is firmly held, centered and protected, for instance against shaking back and forth or while transporting the container.        
 
         [0008]     The elastic means may preferably be conformed like a bellows or a spring. The elastic means may also comprise a spring element set up coaxially to the central axis encompassing elastic webs set up in a helical or coaxial form with respect to the central axis. The configuration of the spring element fitted with such webs allows an application of large through opening passages for the impregnation agent, so as to generate a low resistance while flowing through the spring element. Further advantages are in the fact that the holding force on the implant is uniform and centers the implant. The webs may exhibit upper ends turned toward the cover, which open out in a central plate set up concentrically to the central axis and fitted with perforations, whose diameter measured in a direction orthogonal to the central axis d may measure between about 0.001% and 99.999% and preferably between about 0.1% and 99.9% of the cavity diameter D measured orthogonally to the central axis. The diameter d may be between about 1% and 99%, and preferably between about 5% and 95% of the diameter D. The diameter d is typically between about 10% and 90%, and preferably between about 20% and 80% of the diameter D. The diameter d is advantageously between about 25% and 75%, and preferably between about 30% and 40% of the diameter D. The small diameter of the central plate with respect to that of the cavity allows only a small portion of the implant surface not to be exposed to the impregnation agent. A further advantage is that the holding force on the implant is uniform and that the implant is also centered.  
         [0009]     In another embodiment, the webs may have lower ends opening out into an outer ring of the spring element. The outer ring may in this case be seated in the cavity. After the cover is screwed tight, the elastic means are thus fastened by the spring element pressing against the cover and by being seated in the cavity. Other advantages are based on the fact that the shape of the seal may prevent it from tilting off from the axis and that the dead space of the lower external ring is reduced, so that less blood is needed for a perfusion.  
         [0010]     In an additional embodiment, a gasket may be provided between the container and the lid. This allows the container to shut tightly even under a vacuum condition. In another embodiment, the spring element and the gasket may be formed in a single piece. This results in a simple assembly of the device and prevents a loss of the gasket.  
         [0011]     In a further embodiment, the cavity height H is measured parallel to the central axis is defined by the external ring and the gasket height is measured parallel to the central axis. This makes it possible to apply for instance gaskets or spring elements of different size to define the height of the cavity. A further advantage lies in the reduced production and packing costs, because only a single container may be employed for a multiple number of variously sized implants.  
         [0012]     The height measured parallel to the central axis may alternatively be defined by inner parts of different height, preferably through the lid.  
         [0013]     In still another embodiment, the elastic means exhibit—if measured parallel to the central axis and in an unloaded condition—a height h and are axially compressible by a measure Δh, where the ratio Δh:h lies between about 0.001% and 99.999%, and preferably between about 0.01% and 99.99%. The ratio of Δh: h may typically be between about 0.1% and 99.9%, and preferably between about 1% and 99%. The ratio of Δh:h is advantageously between about 5% and 95%, and preferably between about 10% and 90%. The elastic means are thus compressible to a high degree, so that variously sized implants can be accommodated.  
         [0014]     In a further embodiment, the container is shaped like a cylinder and presents a coaxially arranged inner thread, while the lid comprises an outer thread complementary to the inner thread.  
         [0015]     The container advantageously contains a porous bone replacement material, whose overall volume v is smaller than the volume V of the cavity. The bone replacement material may be available in the form of a block, preferably in the form of a cube, cylinder, hollow cylinder, disc, wedge, cone, truncated cone or a ball. The bone replacement material may be fitted inside an implant so as to communicate at least partially with the surface of the implant itself.  
         [0016]     The implant may be chosen from one or more of the following groups of materials: metal, synthetic material, non-metal, preferably glass, ceramics of different density, and composite ceramics.  
         [0017]     The elastic means may be set up symmetrically or asymmetrically to the central axis. Depending on the configuration or form of the implant, an either symmetrical or asymmetrical construction may offer a better support for the implant.  
         [0018]     The container bottom may be fitted with a centrally or de-centrally perforated connecting piece forming one of the two openings. A centrally or de-centrally perforated connecting piece can also be set up on the lid cover over one of the two opening.  
         [0019]     An impregnation agent may comprise osteoinductive and/or osteogenic substances, in particular bone cells, bone marrow or bone marrow components, blood or blood components or a combination thereof.  
         [0020]     A method for impregnating a porous bone replacement material with an impregnation agent comprising the steps of injecting the impregnation agent using a syringe having a piston. Preferably the syringe is connected to at least one of a lower opening and upper opening of a container so that a block made of porous bone replacement material is surrounded by the impregnation agent and is at least partially submerged in the same. Both openings may be formed as Luer openings with a conically perforated connecting piece connected to the container. Withdrawing the piston of the syringe, so as to create a vacuum in the container, causes the air present in the pores of the bone replacement material to expand so as to move out of the pores and into the surrounding impregnation agent. Because of the closed system the piston motion aspirates the impregnation agent only partially. Pressing the piston of the syringe again into the original position eliminates the vacuum in the container. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     The device is explained in even greater detail in the following exemplary drawings. The device may be better understood by reference to the following drawings, wherein like reference numerals represent like elements. The drawings are merely exemplary to illustrate structure, operation and method of use of the device and certain features that may be used singularly or in combination with other features, and the invention should not be limited to the embodiments shown.  
         [0022]      FIG. 1  is a cross-section of an embodiment of the device according to the invention;  
         [0023]      FIG. 2  is a topside view of the device shown in  FIG. 1 ;  
         [0024]      FIG. 3  is a perspective view of an elastic means as part of the device shown in  FIG. 1  and  2 ;  
         [0025]      FIG. 4  is a sectional view of the elastic means shown in  FIG. 3 ;  
         [0026]      FIG. 5  is a view of the connecting piece marked off by the circle A in  FIG. 1 ;  
         [0027]      FIG. 6  is a topside view of the connecting piece shown in  FIG. 5 ; and  
         [0028]      FIG. 7  is a perspective view of an embodiment of the device and of a syringe. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0029]      FIG. 1  shows an embodiment of the device  14  which comprises a cylindrical container  6  set up coaxially to the central axis  10  and fitted with a lid  8  that is fastenable onto container  6 . The container  6  may have a cavity  13 , an inner thread  7  set up coaxially to the central axis  10  so that the lid  8 , which has on its outer mantle surface  27  an outer thread  9  complementary to the inner thread  7 , may be connected to the container  6  in a detachable manner. The inner thread  7  may extend over the entire axial length of the cavity  13  in the container  6 . Alternatively, a multiple thread extending only up to half of the container  6  may be employed. The outer thread  9  on the lateral mantle surface  27  of the lid  8  may extend over the entire axial length of the lid  8 . The elastic means  19 , which may comprise in one embodiment an axial elastic spring element  30  and a hollow cylinder gasket  31  which may be formed in a single unit, is arranged inside the cavity  13 .  
         [0030]     The hollow cylinder gasket  31  may extend parallel to the central axis  10  between upper end  38  of outer ring  37  which is part of the spring element  30  and lower end  17  of the lid  8 . The lower end  39  of the outer ring  37  rests on bottom  16  of the container  6 , while the upper end  38  of the outer ring  37  is connected to lower end  35  of the gasket  31 . The outer ring  37  may be formed with an outer diameter adapted to the inner diameter of the container  6 , so as to secure the elastic means  19  against shifting in a direction transverse to the central axis  10 .  
         [0031]     The lid  8  may be threaded into the cavity  13  of the container  6 , until the lower end  17  of the lid  8  rests on the upper end  36  of the gasket  31 . The inner thread  7  as well as the outer thread  9  may be formed as multiple threads. The bottom  16  of the container  6  is fitted with a depression  20  concentric to a central axis  10 , where a centrally perforated connecting piece  21  is set up concentric to the central axis  10 . Central perforation  24  of the connecting piece  21  forms opening  4 . Analogous to this, a second connecting piece  25  perforated concentrically to the central axis  10  is set up outside the cover plate  18  of the lid  8 . The connecting pieces  21  and  25  may be formed in an identical manner. The two connecting pieces  21  and  25  alternatively may be formed in a different manner.  
         [0032]     When screwing the lid  8  into the container  6 , a piece of bone replacement material  1  inserted into the cavity  13  of the container  6  is pressed against the upper end  29  of the spring element  30  so that the spring element  30  is compressed by a measure Δh. Owing to the elasticity of the spring element  30 , the body of the bone replacement material  1  is clamped between the upper end  29  of the spring element  30  and cover plate  18  of the lid  8 . The bone replacement material is accommodated inside an implant in such a way that it communicates with the surface of the implant at least in part.  
         [0033]      FIGS. 3 and 4  represent an embodiment of the elastic means  19 , which may consist of a spring element  30  with an outer ring  37  and a truncated-cone type segment arranged at the upper end  38  of the outer ring  37 . This truncated cone type segment  40  comprises webs  34 , whose upper ends  42  open up into a central plate  41  which is arranged concentrically to the central axis  10  at the upper end  29  of the spring element  30  and fitted with perforations  44 , and whose lower ends  43  are connected to the outer ring  37  at element  33 . The truncated cone type segment  40  is conformed in a tapered manner toward the upper end  29  of the spring element  30 , while the webs  34  are spirally arranged around the central axis  10 .  
         [0034]      FIGS. 5 and 6  illustrate the connecting pieces  21 ,  25 , which are identically confirmed as male Luer connecting pieces. Each of the connecting pieces  21 ,  25  comprises at its free end  22  two radially projecting cams  23 , which are formed by two pairs of diametrically opposed segments of a thread  28 , respectively. A standard injector  15  ( FIG. 7 ) conformed as a complementary female Luer connecting piece at its opening toward the connecting piece  21  may be screwed on over each of the connecting pieces  21 ,  25  (Luer connecting piece). The connecting pieces can be chosen so that different adapters may be connected to the same in an airtight fashion. Arranging ( FIG. 1 ) the connecting piece  21  in depression  20  so that the connecting piece  21  cannot project above the bottom  16  of the container  20 , the container  6  can be laid on the floor without tilting over. To facilitate threading the lid  8  into or onto the container, two axially projecting rises  11  are provided on the outer side of the cover plate  18  on the lid  8 , and two axially running grooves  26  are provided on the outer mantle surface of the container  6  ( FIG. 2 ).  
         [0035]     The elastic means  19  may preferably be configured like bellows or a spring. The elastic means  19  may also comprise a spring element set up coaxially to the central axis  10  encompassing elastic webs set up in a helical or coaxial form with respect to the central axis. The configuration of the spring element fitted with such webs allows an application of large through opening passages for the impregnation agent  5 , so as to generate a low resistance while flowing through the spring element. Further advantages are in the fact that the holding force on the implant is uniform and centers the implant. The webs may exhibit upper ends turned toward the cover, which open out in a central plate set up concentrically to the central axis and fitted with perforations, whose diameter measured in a direction orthogonal to the central axis d may measure between about 0.001% and 99.999% and preferably between about 0.1% and 99.9% of the cavity diameter D measured orthogonally to the central axis. The diameter d may be between about 1% and 99%, and preferably between about 5% and 95% of the diameter D. The diameter d is typically between about 10% and 90%, and preferably between about 20% and 80% of the diameter D. The diameter d is advantageously between about 25% and 75%, and preferably between about 30% and 40% of the diameter D. The small diameter of the central plate with respect to that of the cavity allows only a small portion of the implant surface not to be exposed to the impregnation agent. A further advantage is that the holding force on the implant is uniform and that the implant is also centered.  
         [0036]     In another embodiment, the webs  34  may have lower ends opening out into an outer ring of the spring element. The outer ring  37  may in this case be seated in the cavity free of play. After the cover is screwed tight, the elastic means are thus fastened by the spring element pressing against the cover and free from any play in the cavity. Other advantages are based on the fact that the shape of the seal will prevent it from tilting off of the axis and that the dead space of the lower external ring is reduced, so that less blood is needed for the perfusion.  
         [0037]     In an additional embodiment, a gasket  31  may be provided between the container  6  and the lid  8 . This allows the container  6  to shut tightly even under a vacuum condition. In another embodiment, the spring element  30  and the gasket  31  may be formed in a single piece. This results in a simple assembly of the device and prevents a loss of the gasket.  
         [0038]     In a further embodiment, the cavity  13  height H is measured parallel to the central axis defined by the external ring and the gasket height is measured parallel to the central axis  10 . This makes it possible to apply for instance gaskets or spring elements of different size to define the height of the cavity.  
         [0039]     The height measured parallel to the central axis may alternatively be defined by inner parts of different height, preferably through the lid.  
         [0040]     In still another embodiment, the elastic means  19  exhibit—if measured parallel to the central axis  10  and in an unloaded condition—a height h and are axially compressible by a measure Δh, where the ratio Δh:h lies between about 0.001% and 99.999%, and preferably between about 0.01% and 99.99%. The ratio of Δh:h may typically be between about 0.1% and 99.9%, and preferably between about 1% and 99%. The ratio of Δh:h is advantageously between about 5% and 95%, and preferably between about 10% and 90%. The elastic means are thus compressible to a high degree, so that variously sized implants can be accommodated.  
         [0041]     In a further embodiment, the container  6  is shaped like a cylinder and presents a coaxially arranged inner thread, while the lid comprises an outer thread complementary to the inner thread.  
         [0042]     The container  6  advantageously contains a porous bone replacement material, whose overall volume v is smaller than the volume V of the cavity. The bone replacement material may be available in the form of a block, preferably in the form of a cube, cylinder, hollow cylinder, disc, wedge, cone, truncated cone or a ball. The bone replacement material may be fitted inside an implant so as to communicate at least partially with the surface of the implant itself.  
         [0043]     The implant may be chosen from one or more of the following groups of materials: metal, synthetic material, non-metal, preferably glass, ceramics of different density, and composite ceramics.  
         [0044]     The elastic means may be set up symmetrically or asymmetrically to the central axis. Depending on the configuration or form of the implant, an either symmetrical or asymmetrical construction offers a better support for the implant.  
         [0045]     The container bottom may be fitted with a centrally or de-centrally perforated connecting piece forming one of the two openings. A centrally or de-centrally perforated connecting piece can also be set up on the lid cover over one of the two opening.  
         [0046]     The impregnation agent  5  may comprise osteoinductive and/or osteogenic substances, in particular bone cells, bone marrow or bone marrow components, blood or blood components or a combination thereof.  
         [0047]      FIG. 7  shows a container  6  with a body composed of a bone replacement material  1  enclosed in the cavity surrounded by outer wall  2 . The container  6  has two openings  3 ,  4 , which may be airtight connected by a syringe  15 . The syringe may in its cavity contain osteoinductive and/or osteogenic substances, in particular body cells, bone marrow and/or bone marrow elements, blood and/or other blood elements as an impregnation agent  5 . The container  6  illustrated in this case, together with the syringe  15 , serves to perform the following process:  
         [0048]     A) A syringe  15  filled with impregnation agent  5  is preferably connected to the lower opening or both openings  4  of the container  6 . The upper opening  3  remains open. Both openings  3 ,  4  are configured as Luer openings with a conically perforated connecting piece  21 ,  25  connected to the container  6  ( FIGS. 5 and 6 ). The impregnation agent  5  is injected by the piston  12  through the opening  4  into the container  6 , so that the block made of porous bone replacement material  1  is surrounded by the impregnation agent  5  and is partially or preferably wholly submerged in the same;  
         [0049]     B) The upper opening  3  is now closed;  
         [0050]     C) The piston  12  of the syringe  5  is then again withdrawn, so as to create a negative pressure or vacuum in the container  6 . Because of the vacuum, the air present in the pores of the bone replacement material  1  is induced to expand, so as to move out of the pores and into the surrounding impregnation agent  5 . Because this is a closed system, the piston motion aspirates the impregnation agent  5  only partially. This is also possible only if the container  6  still contains air. In addition, a large volume of impregnation agent  5  also exhibits adhering characteristics and thus adheres to the surface of the bone replacement material  1 , without being aspirated by the piston motion;  
         [0051]     D) In a next step, the piston  12  of the syringe  5  is pressed again into the original position, so as to eliminate the vacuum in the container  6 . The block of bone replacement material  1  surrounded by the impregnation agent  5  now absorbs into its pores only impregnation agent  5 , and not air, so that an impregnation of the bone replacement material  1  will occur. The evacuation/elimination of the vacuum drawn with the syringe  5  in the container can be repeated several times to boost the degree of impregnation. Because of its adhesion property and the capillary effect of the structure of the porous bone replacement material  1 , the impregnation agent  5  typically is better absorbed into its interior than air.  
         [0052]     Another embodiment of the process lies in the fact that after coupling the first syringe  15  filled with impregnation agent  5  to one of the two openings  3 ,  4 , the second, unfilled syringe (not shown) is coupled to the other opening  3 ,  4 , and the cavity of the container  6  is evacuated by withdrawing the piston and at the same time aspirating the impregnation agent  5 , through the resulting negative pressure, from the cavity in the syringe  15  into the cavity of the container  6 . The air in the pores of the bone replacement material  1  escapes from the pores. By pressing in the piston of the second syringe, the air is subsequently moved again into the container  6 , so that the vacuum in the cavity of the container  6  is again eliminated and the impregnation agent  5  can penetrate into the pores of the bone replacement material.  
         [0053]     If necessary the piston of one of the syringes can be withdrawn and the container can be evacuated again. The process steps of evacuating and eliminating the vacuum can be simply repeated in this manner, until the pores in the bone replacement material  1  are adequately de-aerated and filled with impregnation agent  5 .  
         [0054]     Another embodiment of the process consists in the fact that the second syringe (not shown) is applied to increase the vacuum. This second syringe can—because it is not filled with impregnation agent  5 —present a considerably greater volume than the first syringe  15  filled with impregnation agent  5 .  
         [0055]     Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.