System and method for mixing bone cement

Abstract

An apparatus for mixing bone cement in a vacuum includes a container for mixing first and second components of a bone cement in a vacuum, the container having a sealed body defining an interior space and a selected quantity of the first component disposed in the interior space. The container is provided with an injection port for admitting the second component into the interior space vacuum source. A mixing paddle is disposed in the interior space and connected to a handle therefor extending out of the container. A plurality of indirect pathways extend between the interior space and the exhaust port which permit gas to pass therethrough out of the interior space, but prevent the bone cement first and second components from passing therethrough.

What is claimed is:  
     
         1 . Apparatus for mixing bone cement in a vacuum, said apparatus comprising: 
 a container for mixing first and second components of a bone cement in a vacuum, said container comprising: 
 a sealed body defining an interior space;  
 a selected quantity of said bone cement first component disposed in said interior space of said sealed body;  
 an injection port formed in said sealed body and communicating with said interior space, said injection port being adapted for interconnection with a holder containing a selected quantity of the bone cement second component, whereby the second component can be introduced into said interior space of said sealed body;  
 an exhaust port formed in said sealed body and communicating with said interior space, said exhaust port being adapted for interconnection with a vacuum source whereby a vacuum can be pulled inside said interior space of said sealed body;  
 an agitator comprising a mixing paddle disposed in said interior space of said sealed body and an actuating handle therefor disposed outside said sealed body; and  
 a plurality of indirect pathways extending between said interior space of said sealed body and said exhaust port, said plurality of indirect pathways being adapted to permit gas to pass out of said interior space of said sealed body via said exhaust port but to prevent said bone first component and the bone cement second component from passing out of said interior space of said sealed body via said exhaust port.  
   
     
     
         2 . Apparatus according to  claim 1  wherein said plurality of indirect pathways are formed at least in part by barrier means disposed between said interior space of said sealed body and said exhaust port, said barrier means comprising an element formed out of non-porous material, with said element having a plurality of passageways extending through said element.  
     
     
         3 . Apparatus according to  claim 2  wherein said element is positioned against an interior surface of said sealed body, and further wherein said interior surface of said sealed body includes a plurality of surface passageways formed therein, said passageways in said barrier means and said surface passageways in said sealed body together forming said indirect pathways.  
     
     
         4 . Apparatus according to  claim 1  wherein said container further comprises an absorbent filter disposed in said exhaust port so that said absorbent filter is located downstream from said indirect pathways but upstream from any vacuum source interconnected with said exhaust port, said absorbent filter being adapted to trap non-gaseous materials exiting the interior of said sealed body via said exhaust port.  
     
     
         5 . Apparatus according to  claim 1  wherein said container comprises a sealed cartridge adapted for use in a cement dispenser.  
     
     
         6 . Apparatus according to  claim 1  wherein said container comprises a sealed mixing bowl.  
     
     
         7 . Apparatus according to  claim 1  wherein said agitator comprises a reciprocal agitator adapted to move said mixing paddle reciprocally within said interior space of said sealed body when said actuating handle is moved reciprocally outside said sealed body.  
     
     
         8 . Apparatus according to  claim 1  wherein said apparatus further comprises: 
 a vacuum line interconnecting said exhaust port with a vacuum source;  
 a check valve disposed in said vacuum line for maintaining a vacuum pulled in the interior of said sealed body by said vacuum source;  
 a vacuum indicator disposed in said vacuum line for indicating when a predetermined level of vacuum has been attained in the interior of said sealed body; and  
 a filter disposed in said vacuum line for trapping selected materials passing through said vacuum line.  
 
     
     
         9 . Apparatus according to  claim 8  wherein said filter is disposed between said vacuum indicator and said check valve.  
     
     
         10 . Apparatus for mixing bone cement in a vacuum, said apparatus comprising: 
 a container for mixing first and second components of a bone cement in a vacuum, said apparatus comprising: 
 a sealed body defining an interior space;  
 a selected quantity of said first bone cement component disposed in said interior space of said sealed body;  
 an exhaust port formed in said sealed body and communicating with said interior space, said exhaust port being adapted for interconnection with a vacuum source whereby a vacuum can be pulled inside said interior space of said sealed body;  
 an agitator comprising a mixing paddle disposed in said interior space of said sealed body and an actuating handle disposed outside said sealed body, with said mixing paddle being connected to said actuating handle by a hollow shaft extending through said sealed body;  
 said hollow shaft comprising a thin-walled exterior tube and a resilient interior tube, with said thin-walled exterior tube being connected to said mixing paddle, and with said thin-walled exterior tube being provided with a breakaway notch adjacent to where said thin-walled exterior tube is connected to said mixing paddle, and with a porous plug being disposed in the central passageway of said resilient interior tube adjacent to where said shaft is connected to said mixing paddle, said porous plug being connected to said resilient interior tube and being adapted to permit gas and the bone cement second component to pass through said porous plug but to prevent said bone first component from passing through said porous plug; and  
 an injection port formed in said actuating handle and communicating with the interior of said resilient interior tube, said injection port being adapted for interconnection with a holder containing a selected quantity of said bone cement second component, whereby said bone cement second component can be introduced into said interior space of said sealed body for mixing with said bone cement first component.  
   
     
     
         11 . Apparatus according to  claim 10  wherein said sealed body comprises a sealed cartridge adapted for use in a cement dispenser.  
     
     
         12 . An ampoule breaker/injector assembly for use in releasing a fluid from an ampoule having a frangible neck, and for guiding the fluid released from the ampoule into a sealed vessel, said assembly comprising: 
 a body having an interior space for receiving the neck of the ampoule and at least a portion of a remainder of the ampoule;    injector means formed in said body and communicating with said interior space, said injector means being adapted for interconnection with the sealed vessel whereby when a vacuum is drawn in the sealed vessel, the vacuum will be extended into said interior space of said body;    first means for causing said ampoule to move longitudinally within said interior space when said ampoule is disposed in said interior space and a vacuum is extended into said interior space; and    second means for causing said frangible neck of said ampoule to break when said ampoule is moved longitudinally within said interior space.    
     
     
         13 . An ampoule breaker/injector assembly according to  claim 12  wherein said second means comprise a wedge disposed in said interior space.  
     
     
         14 . An ampoule breaker/injector assembly according to  claim 12  wherein said first means comprise an O-ring disposed in said interior space.  
     
     
         15 . An ampoule breaker/injector assembly according to  claim 14  wherein said O-ring is in engagement with said ampoule.  
     
     
         16 . An ampoule breaker/injector assembly according to  claim 12  wherein said first means comprise a piston, said piston being adapted to drive said ampoule longitudinally when a vacuum is extended into said interior space.  
     
     
         17 . Apparatus for mixing bone cement in a vacuum, said apparatus comprising: 
 a container for mixing first and second components of a bone cement in a vacuum, said container comprising: 
 a sealed body defining an interior space;  
 a selected quantity of said bone cement first component disposed in said interior space of said sealed body;  
 an injection port formed in said sealed body and communicating with said interior space, said injection port being adapted for interconnection with a holder containing a selected quantity of the bone cement second component, whereby the second component can be introduced into said interior space of said sealed body;  
 an exhaust port formed in said sealed body and communicating with said interior space, said exhaust port being adapted for interconnection with a vacuum source whereby a vacuum can be pulled inside said interior space of said sealed body;  
 an agitator comprising a mixing paddle disposed in said interior space of said sealed body and an actuating handle therefor disposed outside said sealed body; and  
   an ampoule breaker/injector assembly for use in releasing the bone cement second component from an ampoule having a frangible neck, and for guiding the bone cement second component released from the ampoule into said sealed body, said assembly comprising: 
 a housing having defined space for receiving the neck of the ampoule and at least a portion of a remainder of the ampoule;  
 injector means formed in said housing and communicating with said defined space, said injector means being adapted for interconnection with said sealed body, whereby when a vacuum is drawn in said sealed body, said vacuum will be extended into said defined space of said housing;  
 first means for causing the ampoule to move longitudinally within said defined space when the ampoule is disposed in said defined space and a vacuum is extended into said defined space; and  
 second means for causing the frangible neck of the ampoule to break when the ampoule is moved longitudinally within said defined space;  
   whereby bone cement second component released from the ampoule into said defined space in said housing can be introduced into said interior space of said sealed body.    
     
     
         18 . Apparatus according to  claim 17  wherein said apparatus is configured so that longitudinal motion of said actuating handle is transferred to the ampoule.  
     
     
         19 . Apparatus according to  claim 18  wherein a portion of said actuating handle engages a portion of the ampoule.  
     
     
         20 . Apparatus according to  claim 18  wherein said first means comprise a piston disposed in said housing and engageable with a portion of the ampoule, and a portion of said actuating handle engages a portion of said piston.  
     
     
         21 . Apparatus comprising: 
 a substantially rigid vessel defining an interior region;    a frangible neck formed on said vessel and communicating with said interior region of said vessel;    a selected quantity of a liquid bone cement disposed in said interior region of said vessel; and    a gas column disposed in said interior region of said vessel.    
     
     
         22 . A method for mixing first and second components of a bone cement, said method comprising the steps of: 
 providing a sealed body defining an interior space and having therein a selected quantity of said first component, and having therein an injection port, an exhaust port, an agitator means disposed in said interior space and connected to a handle disposed at least in part outside of said interior space, and having indirect pathways extending between said interior space and said exhaust port but prevent said first and second components from passing out of said interior space via said exhaust port;    placing a holder having said second component therein in communication with said injection port to place said holder in communication with said interior space;    placing a vacuum source in communication with said exhaust port to draw a vacuum in said interior space, to thereby draw said second component into said interior space; and    operating said handle to move said agitator means in said interior space to mix said first and second components while continuing said drawing of said vacuum in said interior space, said pathways permitting passage of gas therethrough from said interior space but preventing passages of said first and second components therethrough.    
     
     
         23 . A method for mixing first and second components of a bone cement, said method comprising the steps of: 
 providing a sealed body defining an interior space and having therein a selected quantity of said first component, and having therein an exhaust port, an agitator means disposed in said interior space and connected to a handle connected to said agitator means and extending outside of said interior space, and having barrier means in said interior space adjacent said exhaust port, said barrier means being adapted to permit gas to pass therethrough and out of said interior space via said exhaust port but prevent passage therethrough of said first and second components, said handle having an injection port therein outside of said interior space and a channel extending through said handle to proximate said agitator means;    placing a vacuum source in communication with said exhaust port to draw a vacuum in said interior space and said channel;    introducing said second component via said injection port and said channel into said interior space; and    operating said handle to move said agitator means in said interior space to mix said first and second components to form bone cement, while continuing said drawing of said vacuum in said interior space, said barrier means permitting passage of gas therethrough from said interior space but preventing passage therethrough of said first and second components.    
     
     
         24 . Apparatus comprising: 
 a substantially rigid vessel defining an interior region;    an egress port formed on said rigid vessel and communicating with said interior region;    a piston movably disposed in said interior region of said vessel and making a close sliding fit therewith so as to define a volume of variable size; and    a selected quantity of a liquid bone cement component disposed in said volume.    
     
     
         25 . Apparatus comprising: 
 a substantially flexible vessel defining an interior region;    an egress port formed on said flexible vessel and communicating with said interior region; and    a selected quantity of a liquid bone cement component disposed in said interior region of said flexible vessel.    
     
     
         26 . Apparatus comprising: 
 a substantially rigid vessel defining an interior region;    a frangible neck formed on said vessel and communicating with said interior region of said vessel;    a selected quantity of a liquid bone cement disposed in said interior region of said vessel;    a gas column disposed in said interior region of said vessel; and    an injector element for receiving the neck of said vessel and at least a portion of the remainder of said vessel and for making an airtight seal with said at least a portion of the remainder of said vessel, said injector device including an egress port.