Patent Publication Number: US-11653963-B2

Title: Dispensing system and methods of use

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/668,918, filed on Aug. 4, 2017, which is hereby expressly incorporated herein by reference, in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure generally relates to medical devices, and more particularly to devices, systems and methods for dispensing a material, such as, for example, bone cement. 
     BACKGROUND 
     Many medical procedures employ medical grade bone cement in connection with the restoration and strengthening of bone structures. For example, surgeons commonly use bone cement in order to fill voids in bone. It is desirable to use bone cement, such as an adhesive bone cement, to hold small bone fragments in place to allow for healing, when methods such as traditional plate and screw methods of reattachment are not feasible. Only a small amount of bone cement may be required to fill small gaps between the bone fragments in order to glue the fragments together. For example, volumes of cement under one cubic centimeter may be used. In such applications, cement is typically dispensed to a bone to fill in voids or spaces in the bone or between medical devices or implants attached to or embedded within the bone. These dispensing devices may include systems as simple as syringes and as complex as electronically controlled valves. 
     The bone cement may be a mixture of different ingredients, and, before applying the bone cement to a repair site, the cement may be prepared by mixing a liquid monomer with a powder in a mixing device. The prepared bone cement can have various viscosities, and some may have quite a high viscosity, with a consistency like a tacky paste. For example, a typical adhesive bone cement may have a viscosity greater than 80 Pascal-seconds. Due to the high viscosity of the bone cement, it is often difficult to load the prepared cement into a syringe or other device. Indeed, the high viscosity of the bone cement requires a great amount of force to transfer the prepared bone cement from the mixing device to the syringe or other device. This disclosure describes improvements over these prior art technologies. 
     SUMMARY 
     In one embodiment, in accordance with the principles of the present disclosure, a dispensing system is provided that comprises a main body including a base and an extension extending from the base. The extension comprises an inner surface defining a passageway. The main body comprises an opening that extends through the extension. The opening is in communication with the passageway. A first plunger is configured to be positioned within the passageway. The first plunger comprises a lumen extending through and between opposite proximal and distal end surfaces of the first plunger. A second plunger is configured to be positioned within the lumen. 
     In one embodiment, in accordance with the principles of the present disclosure, a dispensing system is provided that includes a main body comprising a base and an extension extending from the base. The extension comprises an inner surface defining a passageway. The main body comprises an opening that extends through the extension. The opening is in communication with the passageway. The extension comprises a fitting. The opening extends through the fitting. The main body comprises a valve that is coupled to the fitting. The valve comprises a channel. The valve is movable between a first orientation in which the channel is offset from the opening and a second orientation in which the channel is aligned with the opening. A first plunger is movably positioned within the passageway. The first plunger comprises a lumen extending through and between opposite proximal and distal end surfaces of the first plunger. A distal end of the first plunger comprises an enlarged portion that forms a seal with the inner surface when the first plunger is inserted into the passageway. A second plunger is movably positioned within the lumen. An outer surface of the second plunger forms a seal with an inner surface of the first plunger that defines the lumen when the second plunger is inserted into the lumen. Bone cement is positioned within the lumen between the base and the plungers. A syringe is coupled to the fitting. A proximal end of the first plunger comprises a flange that engages a flange of the extension when the first plunger is fully inserted into the passageway. The flange of the first plunger engages a flange of the second plunger when the second plunger is fully inserted into the lumen. 
     In one embodiment, in accordance with the principles of the present disclosure, a method of dispensing a material is provided. The method comprises positioning a material in a passageway of a main body. The main body comprises a base and an extension extending from the base. The extension comprises an inner surface defining the passageway. The main body comprises an opening that extends through the extension. The opening is in communication with the passageway. A second plunger is inserted into a lumen of a first plunger. The first plunger is inserted into the passageway such that the material moves into the lumen. The second plunger is translated axially within the lumen such that the material moves through the opening. 
     Additional features and advantages of various embodiments will be set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practice of various embodiments. The objectives and other advantages of various embodiments will be realized and attained by means of the elements and combinations particularly pointed out in the description and appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will become more readily apparent from the specific description accompanied by the following drawings, in which: 
         FIG.  1    is a side, perspective view of one embodiment of components of a dispensing system in accordance with the principles of the present disclosure; 
         FIG.  2    is a side, perspective view, in part phantom, of components of the system shown in  FIG.  1   ; 
         FIG.  3    is a side, perspective view, in part phantom, of components of the system shown in  FIG.  1   ; 
         FIG.  4    is a side, cross sectional view of components of the system shown in  FIG.  1   ; 
         FIG.  5    is a side, perspective view, in part phantom, of components of the system shown in  FIG.  1   ; 
         FIG.  6    is a side, perspective view, in part phantom, of components of the system shown in  FIG.  1   ; 
         FIG.  7    is a side, perspective view of components of the system shown in  FIG.  1   ; 
         FIG.  8    is a side, perspective view of components of the system shown in  FIG.  1   ; 
         FIG.  9    is a side, cross sectional view of components of the system shown in  FIG.  1   ; 
         FIG.  10    is a side, cross sectional view of components of the system shown in  FIG.  1   ; 
         FIG.  11    is a bottom, perspective view of components of the system shown in  FIG.  1   ; 
         FIG.  12    is a side, perspective view of one embodiment of components of the system shown in  FIG.  1   ; 
         FIG.  13    is a side, cross sectional view of portions of components of the system shown in  FIG.  1   ; 
         FIG.  14    is a side, perspective view of a portion of a component of the system shown in  FIG.  1   ; 
         FIG.  15    is a side, cross sectional view of portions of components of the system shown in  FIG.  1   ; and 
         FIG.  16    is a side, cross sectional view of portions of components of the system shown in  FIG.  1   . 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure generally relates to medical devices, and more particularly to devices, systems and methods for dispensing a material. To minimize the amount of force required to transfer and/or dispense bone cement from bone filler devices, multi-tap, or CDS cartridges, a dispensing system including a two stage plunger is provided in accordance with the principles of the present disclosure. In some embodiments, the dispensing system is similar to a telescoping hydraulic cylinder and utilizes a first stage plunger, such as, for example, an outer plunger that is hollow in the center. A second stage plunger, such as for example, an inner plunger includes a valve, such as, for example, a check valve or a vent valve. The inner plunger is inserted into the hollow portion of the outer chamber to form a plunger assembly. After bone cement is mixed within a mixer, the plunger assembly is inserted into a mixing chamber of the mixer and is advanced until the plunger assembly touches the bone cement in the mixing chamber. Air in the mixing chamber can exit the mixing chamber through the valve in the inner plunger as the plunger assembly is inserted into the mixing chamber. The outer plunger is advanced all the way down into the mixing chamber while the inner plunger is allowed to move freely. By advancing the outer plunger, the bone cement is forced into the outer plunger, which is smaller in diameter than the mixing chamber. The outer plunger is connected to the mixer by a twist lock or clips, for example, to fix the outer plunger relative to the mixer. The bone cement is then dispensed from the mixer by opening an outlet valve on the mixer and pressing the inner plunger down. Advancing the inner plunger forces the cement out through the outlet valve and into a bone filler device, multi-tap, or CDS cartridge. In some embodiments, the bone filler device is a syringe. In some embodiments, the mixing chamber has an inner diameter that is larger than the inner diameter of the outer plunger. This benefits the user as the smaller surface area of the inner plunger concentrates the force applied by the user, thus increasing the pressure they are able to generate. A change from a larger diameter to a smaller diameter increases the pressure generated with the same input force. For example, a change from a diameter of about 1.25 inches to about 0.75 inches increases the pressure generated by about 2.5 times. As such, the user can apply less force to dispense the same amount of bone cement from the mixer. 
     The dispensing system disclosed herein is configured to provide a plurality of benefits including, among other things, reducing the amount of force needed to dispense a material, such as, for example, bone cement. In some embodiments, the dispensing system is configured to reduce the amount of force needed to dispense the material by 2.5 times or more with the same input force. In some embodiments, the dispensing system is configured to reduce the amount of force needed to dispense the material by less than 2.5 times with the same input force. The dispensing system disclosed herein is configured to be used with known products used to mix and/or dispense materials, such as, for example syringes and other devices so as to have minimal impact on existing product validations. The dispensing system disclosed herein is configured to be low in cost. In some embodiments, one or more of the components of the dispensing system disclosed herein may be disposable. The dispensing system disclosed herein is configured to be used as a single or dual stage plunger. 
     In some embodiments, the dispensing system disclosed herein includes a mixer, a first stage plunger and a second stage plunger. The dispensing system disclosed herein may be used to mix and/or dispense a material, such as, for example, bone cement. In some embodiments, the bone cement may be mixed within the mixer using mixing paddles. The mixing paddles are removed after the bone cement is mixed and the two stage plunger is inserted into a mixing chamber of the mixer as an assembly. Air in the mixing chamber can escape through a vent in one of the plungers. In some embodiments, the assembly is inserted only part way into the mixing chamber. The first stage plunger is moved relative to the mixer and the second stage plunger until the first stage plunger is fully seated within the mixing chamber. By plunging the first stage plunger into the mixer, the mixed bone cement is forced into an inner cavity of the first stage plunger. The first stage plunger is connected to the mixer by a twist lock or clips, for example, such that the first stage plunger is fixed to the mixer to prevent the first stage plunger from moving axially relative to the mixer. The inner cavity of the first stage plunger has a smaller inner diameter than the mixing chamber to allow the same input force to create more pressure on the bone cement. This amplification in pressure means that less effort is needed for dispensing the bone cement from the mixer. A valve of the mixer is opened by moving one or more extensions of the valve into a delivery position. The second stage plunger is then plunged as needed until the bone cement exits the mixer and fills a cartridge, such as, for example a CDS cartridge or another device, such as, for example, a bone filler device. 
     As shown below, reducing the diameter of mixing chamber by allowing the bone cement to enter the inner cavity of the first stage plunger and then expelling the bone cement from the first stage plunger using the second stage plunger reduces the amount of force needed to dispense the bone cement from the mixer. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                   
               
               
                   
                   
                   
                   
                   
                   
                 % 
               
               
                   
                 Surface 
                   
                   
                   
                   
                 increase 
               
               
                 Diameter 
                 Area 
                 Lbf 
                 Pressure 
                 Volume 
                 Length 
                 from 
               
               
                 (in) 
                 (in 2 ) 
                 (est.) 
                 (psi) 
                 (cc) 
                 (in) 
                 current 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 1.23 (current) 
                 1.19 
                 25 
                 21.0 
                 20 
                 1.03 
                 N/A 
               
               
                 1 
                 0.79 
                 25 
                 31.8 
                 20 
                 1.55 
                 151% 
               
               
                 0.75 
                 0.44 
                 25 
                 56.6 
                 20 
                 2.76 
                 269% 
               
               
                 0.625 
                 0.31 
                 25 
                 81.5 
                 20 
                 3.98 
                 387% 
               
               
                 0.5 
                 0.20 
                 25 
                 127.3 
                 20 
                 6.22 
                 605% 
               
               
                 0.375 
                 0.11 
                 25 
                 226.4 
                 20 
                 11.05 
                 1076%  
               
               
                   
               
            
           
         
       
     
     For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing quantities of ingredients, percentages or proportions of materials, reaction conditions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. 
     Notwithstanding the numerical ranges and parameters set forth herein, the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a range of “1 to 10” includes any and all subranges between (and including) the minimum value of 1 and the maximum value of 10, that is, any and all subranges having a minimum value of equal to or greater than 1 and a maximum value of equal to or less than 10, e.g., 5.5 to 10. 
     Reference will now be made in detail to certain embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the illustrated embodiments, it will be understood that they are not intended to limit the invention to those embodiments. On the contrary, the invention is intended to cover all alternatives, modifications, and equivalents that may be included within the invention as defined by the appended claims. 
     The headings below are not meant to limit the disclosure in any way; embodiments under any one heading may be used in conjunction with embodiments under any other heading. 
     It is noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the,” include plural referents unless expressly and unequivocally limited to one referent. Thus, for example, reference to “a chemical denervation agent” or a “device” includes one, two, three or more chemical denervation agents or one, two, three or more devices. 
     This disclosure is directed to a dispensing system  10 . In some embodiments, the components of dispensing system  10  can be fabricated from biologically acceptable materials suitable for medical applications, including metals, synthetic polymers, ceramics and bone material and/or their composites, depending on the particular application and/or preference of a medical practitioner. For example, the components of dispensing system  10 , individually or collectively, can be fabricated from materials such as stainless steel alloys, commercially pure titanium, titanium alloys, Grade 5 titanium, super-elastic titanium alloys, cobalt-chrome alloys, stainless steel alloys, superelastic metallic alloys (e.g., Nitinol, super elasto-plastic metals, such as GUM METAL® manufactured by Toyota Material Incorporated of Japan), ceramics and composites thereof such as calcium phosphate (e.g., SKELITE™ manufactured by Biologix Inc.), thermoplastics such as polyaryletherketone (PAEK) including polyetheretherketone (PEEK), polyetherketoneketone (PEKK) and polyetherketone (PEK), carbon-PEEK composites, PEEK-BaSO 4  polymeric rubbers, polyethylene terephthalate (PET), fabric, silicone, polyurethane, silicone-polyurethane copolymers, polymeric rubbers, polyolefin rubbers, hydrogels, semi-rigid and rigid materials, elastomers, rubbers, thermoplastic elastomers, thermoset elastomers, elastomeric composites, rigid polymers including polyphenylene, polyamide, polyimide, polyetherimide, polyethylene, epoxy, bone material including autograft, allograft, xenograft or transgenic cortical and/or corticocancellous bone, and tissue growth or differentiation factors, partially resorbable materials, such as, for example, composites of metals and calcium-based ceramics, composites of PEEK and calcium based ceramics, composites of PEEK with resorbable polymers, totally resorbable materials, such as, for example, calcium based ceramics such as calcium phosphate, tri-calcium phosphate (TCP), hydroxyapatite (HA)-TCP, calcium sulfate, or other resorbable polymers such as polyaetide, polyglycolide, polytyrosine carbonate, polycaroplaetohe and their combinations. 
     Various components of dispensing system  10  may have material composites, including the above materials, to achieve various desired characteristics such as strength, rigidity, elasticity, compliance, biomechanical performance, durability and radiolucency or imaging preference. The components of dispensing system  10 , individually or collectively, may also be fabricated from a heterogeneous material such as a combination of two or more of the above-described materials. The components of dispensing system  10  may be monolithically formed, integrally connected or comprise fastening elements and/or instruments, as described herein. 
     Dispensing system  10  includes a mixer, such as, for example, a main body  12  comprising a base  14  and an extension  16  extending from base  14 . Base  14  is dome-shaped and includes opposite end surfaces  18 ,  20 . Extension  16  extends from an end  22  that is coupled to end surface  20  and an opposite end  24 . In some embodiments, end  22  is monolithically and/or integrally formed with end surface  20  such that extension  16  cannot be removed from base  14  without breaking base  14  and/or extension  16 . In some embodiments, extension  16  is removably coupled to base  14 . In some embodiments, extension  16  can be variously connected with base  14 , such as, for example, frictional engagement, threaded engagement, mutual grooves, screws, adhesive, nails, barbs and/or raised element. 
     In some embodiments, end surfaces  18 ,  20  are each planar and extend parallel to one another. In some embodiments, end surface  20  may be disposed at alternate orientations, relative to end surface  18 , such as, for example, transverse, and/or other angular orientations such as acute or obtuse, co-axial and/or may be offset or staggered. An outer surface of base  14  is convexly curved from end surface  18  to end surface  20 . In some embodiments, the outer surface of base  14  is continuously curved from end surface  18  to end surface  20 . In some embodiments, the outer surface of base  14  has a continuously radius of curvature from end surface  18  to end surface  20 . Base  14  has a maximum height that is defined by the distance from end surface  18  to end surface  20 . In some embodiments, base  14  is hollow to reduce the material used to form base  14 . In some embodiments, base  14  is substantially hollow and includes one or a plurality of support structures, such as, for example, ribs  26 , as shown in  FIGS.  2 ,  3 ,  5 ,  6  and  11   , to provide strength and/or rigidity to base  14 . In some embodiments, base  14  includes a plurality of ribs  26  that define a grid pattern, with each of ribs  26  having opposite ends that each engage an inner surface of base  14 . 
     Extension  16  is substantially cylindrical. End  24  of extension  16  includes a flange  28  that extends outwardly from an outer surface of extension  16  such that flange  28  defines a maximum width of extension  16 . In some embodiments, flange  28  has an oblong cross sectional configuration such that flange  28  has a maximum diameter along a transverse axis T 1 , as shown in  FIG.  1   . Extension  16  comprises an inner surface  30  that defines a mixer chamber, such as, for example, a passageway  32  that extends through flange  28 . End surface  20  of base  14  defines a distal limit of passageway  32 , as shown in  FIG.  9   , for example. Passageway extends through flange  28 . Passageway  32  has a uniform diameter along the entire length of passageway  32 . Passageway  32  has a circular cross sectional configuration. In some embodiments, flange  28  and/or passageway  32  may have various cross section configurations, such as, for example, circular, oval, oblong, triangular, rectangular, square, polygonal, irregular, uniform, non-uniform, variable, tubular and/or tapered. In some embodiments, the outer surface of extension  16  includes markings, such as, for example, graduated lines  34  and indicia  36  that indicate the volume of a material M positioned within passageway  32 . 
     Extension  16  comprises a single opening  38  that extends through and between surface  30  and the outer surface of extension  16 , as best shown in  FIG.  4   . Opening  38  is in communication with passageway  32  and extends perpendicular to surface  30  and the outer surface of extension  16 . In some embodiments, opening  38  may be disposed at alternate orientations, relative to surface  30  and the outer surface of extension  16 , such as, for example, transverse and/or other angular orientations such as acute or obtuse, co-axial and/or may be offset or staggered. 
     Main body  12  includes a fitting  40  that is coupled to extension  16 . Fitting  40  includes a hub  42  that is configured to couple main body  12  to another component of dispensing system  10 , such as, for example, a syringe  44  ( FIG.  6   ), via a threaded configuration or a Luer lock, as discussed herein. For example, in one embodiment, hub  42  may include an internal thread  46  ( FIG.  4   ) that mates with an external thread on one end of syringe  44  to couple syringe  44  to hub  42 . Hub  42  includes a duct  48  and a cavity  50  that extends perpendicular to duct  48 , as best shown in  FIG.  4   . Fitting  40  includes a valve  52  having a valve body  54  that is rotatably positioned in cavity  50 . In some embodiments, cavity  50  has a circular cross sectional configuration and valve body  54  is cylindrical to facilitate rotation of valve body  54  within cavity  50 . A channel  56  extends through the width of valve body  54 , as best shown in  FIG.  4   . In some embodiments, valve  52  includes ears or tabs  58  at opposite ends of valve body  54  body to facilitate rotation of valve body  54  within cavity  50  to move valve  52  between a first orientation, shown in  FIGS.  1 - 3 ,  7 ,  8  and  12   , in which valve body  54  blocks channel  56  and a second orientation, shown in  FIGS.  4 - 6   , in which channel  56  is aligned with opening  38  and duct  48 , as discussed herein. That is, channel  56  is not aligned with opening  38  or duct  48  when valve  52  is in the first orientation. 
     An outer or first stage plunger, such as, for example, plunger  60  is configured for movable disposal in passageway  32 . Plunger  60  extends from an end surface  62  to an opposite end surface  64 . Plunger  60  includes a wall  66  comprising opposite inner and outer surfaces  68 ,  70 . Surface  68  defines a lumen  72  that extends between and through end surfaces  62 ,  64 . Lumen  72  has a uniform diameter along the entire length of lumen  72 . Lumen  72  has a circular cross sectional configuration. In some embodiments, lumen  72  may have various cross section configurations, such as, for example, oval, oblong, triangular, rectangular, square, polygonal, irregular, uniform, non-uniform, variable, tubular and/or tapered. Mien material M is positioned within passageway  32 , material M may enter lumen  72  when plunger  60  is positioned within passageway  32 , as discussed herein. 
     A distal end of plunger  60  includes an enlarged portion comprising a pair of spaced apart circumferential lips  74   a ,  74   b  that each extend outwardly from surface  70 . Lips  74   a ,  74   b  define a groove  75  therebetween, as shown in  FIGS.  1  and  12   , for example. In some embodiments, a gasket, such as, for example, an O-ring  76  is positioned in groove  75  such that outer surfaces of lips  74   a ,  74   b  and/or O-ring  76  form an air tight and/or water tight seal with surface  30  when plunger  60  is positioned within passageway  32  of extension  16 . Lips  74   a ,  74   b  and/or O-ring  76  maintain the seal as plunger  60  moves axially in opposite directions within passageway  32 . In some embodiments, wall  66  and/or lips  74   a ,  74   b  may be formed from a rigid material, such as, for example, one or more of the materials discussed herein. Lips  74   a ,  74   b  may be integrally and/or monolithically formed with wall  66 . In some embodiments, O-ring  76  may be formed of a material that is different than the material that forms wall  66  and/or lips  74   a ,  74   b . In some embodiments, O-ring  76  may be formed from an elastomeric material. In some embodiments, O-ring  76  is removable. Plunger  60  is shown in  FIGS.  1  and  12    with O-ring  76  removed. In some embodiments, plunger  60  comprises a tapered portion  78  that extends distally from lip  74   a , as shown in  FIG.  4   . A lower surface of portion  78  defines end surface  62 . In some embodiments, portion  78  is formed from the same material that forms wall  66  and/or lips  74   a ,  74   b . In some embodiments, portion  78  is formed from material that is different than the material that forms wall  66  and/or lips  74   a ,  74   b . In some embodiments, portion  78  is formed from an elastomeric material such that end surface  62  forms a seal with end surface  20  when end surface  62  contacts end surface  20 . 
     In some embodiments, proximal end of plunger  60  includes an enlarged portion comprising a circumferential lip  80  that extends outwardly from surface  70 . In some embodiments, wall  66  and/or lip  80  may be formed from a rigid material, such as, for example, one or more of the materials discussed herein. Lip  80  may be integrally and/or monolithically formed with wall  66 . The proximal end of plunger  60  includes a flange  82  positioned proximally of lip  80 . In some embodiments, flange  82  has an oblong cross sectional configuration such that flange  82  has a maximum diameter along a transverse axis T 2 , as shown in  FIG.  1   . An upper surface of flange  82  defines end surface  64 . Flange  82  has a maximum diameter that is greater than maximum diameter of lip  80  and passageway  32  such that flange  82  is prevented from entering passageway  32 . A bottom surface  82   a  of flange  82  is configured to directly engage a top surface  28   a  of flange  28  when plunger  60  is fully inserted into passageway  32 . In some embodiments, flange  82  includes a sidewall  82   b  that overlaps a sidewall  28   b  of flange  28  when surface  82   a  of flange  82  directly engages surface  28   a  of flange  28 , as discussed herein. Plunger  60  is configured such that lip  80  is positioned within passageway  32  when surface  82   a  of flange  82  directly engages surface  28   a  of flange  28  and sidewall  82   b  of flange  82  overlaps a sidewall  28   b  of flange  28 . Plunger  60  is configured such that end surface  62  of plunger  60  directly engages end surface  20  when surface  82   a  of flange  82  directly engages surface  28   a  of flange  28 . In some embodiments, flange  82  may have various cross section configurations, such as, for example, circular, oval, circular, triangular, rectangular, square, polygonal, irregular, uniform, non-uniform, variable, tubular and/or tapered. 
     In some embodiments, plunger  60  includes spaced apart struts  84  that each extend continuously from lip  74   b  to lip  80 . Struts  84  are disposed radially about wall  66 . In some embodiments, struts  84  are evenly spaced apart from one another. Struts  84  each have a convexly curved outer surface such that the outer surfaces of struts  84  are flush with the outer surfaces of lips  74   b ,  80 . The outer surfaces of struts  84  are continuously curved along the length of struts  84  and conform to the curvature of surface  30  of extension  16  such that the outer surfaces of struts  84  directly engage surface  30  and form an air tight and/or water tight seal with surface  30  as plunger  60  translates axially in opposite directions within passageway  32 . When the outer surfaces of struts  84  directly engage surface  30 , surface  70  of wall  66  is spaced apart from surface  30 , as shown in  FIGS.  2 - 6   . 
     In some embodiments, flange  82  of plunger  60  forms a twist lock with flange  28  of extension  16 , as shown in  FIGS.  7 - 11   , to connect plunger  60  with extension  16  such that plunger  60  is prevented from moving axially in opposite directions relative to extension  16  within passageway  32 . Flange  82  of plunger  60  includes an inward projection  82   d  having a vertical surface that faces wall  66  of plunger  60 , as shown in  FIGS.  9 - 11   . A top surface of projection  82   d  faces bottom surface  82   a  of flange  82  and is configured to directly engage a bottom surface  28   c  of flange  28  when the twist lock is in a locked position, as shown in  FIGS.  9 - 11   . In particular, plunger  60  is inserted into passageway  32  and is moved axially relative to extension  16  in the direction shown by arrow A in  FIG.  2    until plunger  60  is fully inserted into passageway  32  and axis T 1  extends transverse to axis T 2 , as shown in  FIG.  7   . In some embodiments, axis T 1  may extend perpendicular to axis T 2 . When axis T 1  extends transverse to axis T 2 , the twist lock is in an unlocked position such that plunger  60  is free to translate axially relative to extension  16 . Plunger  60  is then rotated in a clockwise direction or counterclockwise direction relative to extension  16  such that axis T 1  is parallel and/or coaxial with axis T 2 , as shown in  FIG.  8   . In some embodiments, plunger  60  is rotated 90 degrees in a clockwise direction relative to extension  16  until axis T 1  is parallel and/or coaxial with axis T 2 . When axis T 1  is parallel and/or coaxial with axis T 2  the twist lock is in the locked position, which prevents plunger  60  from moving axially in opposite directions relative to extension  16  within passageway  32 . It is envisioned that plunger  60  may be locked with extension  16  using other locking mechanisms to prevent plunger  60  from translating axially in opposite directions relative to extension  16 . For example, in some embodiments, lip  80  may include an outer thread that mates with an inner thread of inner surface  30  of extension  16  to connect plunger  60  with extension  16  such that plunger  60  is prevented from moving axially relative extension  16  within passageway  32 . 
     In some embodiments, system  10  includes clips, such as, for example, a cap  86  ( FIG.  12   ) configured for disposal of flanges  28 ,  82  to fix plunger  60  relative to main body  12  when plunger  60  is fully inserted into passageway  32  to prevent plunger  60  from moving axially relative to extension  16  and to prevent plunger  60  from rotating relative to extension  16 . That is, plunger  60  is prevented from moving axially in opposite directions when flanges  28 ,  82  are disposed in cap  86 . Cap  86  includes a first part  88  and a second part  90 . Part  90  is identical to part  88 . Parts  88 ,  90  each include an arcuate cutout  92  that extends through opposite top and bottom surfaces of parts  88 ,  90 . Cutouts  92  form an opening that is coaxial with lumen  72  when a lateral surface  94  of part  88  engages a lateral surface  94  of part  90 . The opening defined by cutouts  92  has the same width and diameter as lumen  72  such that an inner or second stage plunger, such as, for example, a plunger  96  can be inserted through the opening defined by cutouts  92  and into lumen  72 , as discussed herein. Parts  88 ,  90  each include a lateral cavity  95  positioned between the top and bottom surfaces of parts  88 ,  90 . Cavities  95  are each configured for disposal of portions of flanges  28 ,  82  when surface  94  of part  88  engages surface  94  of part  90 . 
     Plunger  96  extends between an end  98  and an end  100 . End  100  includes a flange  102  having a diameter that is greater than the diameter of lumen  72  such that flange  102  is not inserted into lumen  72  when plunger  96  is fully inserted into lumen  72 . Rather, flange  102  engages flange  82  when plunger  96  is fully inserted into lumen  72 . That is, a bottom surface  102   a  of flange  102  directly engages a top surface  82   c  of flange  82  when plunger  96  is fully inserted into lumen  72  to prevent plunger  96  from translating distally relative to plunger  60 . Plunger  96  has a maximum length such that when plunger  96  is fully inserted into lumen  72 , an end surface of end  98  of plunger  96  does not extend through end surface  62  of plunger  60 . That is, the end surface of end  98  is positioned within lumen  72  when plunger  96  is fully inserted into lumen  72 . Plunger  96  includes an enlarged tip  104  and a body  106  that extends continuously from flange  102  to tip  104 . Body is cylindrical and has a uniform diameter from flange  102  to tip  104 . Tip  104  has a maximum diameter that is greater than a maximum diameter of body  106 . The maximum diameter of tip  104  is slightly less than the diameter of lumen  72  such that an outer surface of tip  104  directly engages surface  68  of plunger  60  to form an air tight or water tight seal with surface  68  as tip  104  moves axially within lumen  72 . When the outer surface of tip  104  directly engage surface  68 , the outer surface of body  106  is spaced apart from surface  68 , as shown in  FIGS.  2 - 6   . 
     In some embodiments, body  106  and/or flange  102  may be formed from a rigid material, such as, for example, one or more of the materials discussed herein. In some embodiments, tip  104  is formed from the same material that forms body  106  and/or flange  102 . In some embodiments, tip  104  is formed from material that is different than the material that forms body  106  and/or flange  102 . In some embodiments, tip  104  is formed from an elastomeric material such that tip forms a seal with surface  68  when the outer surface of tip  104  contacts surface  68 . In some embodiments, tip  104  includes spaced apart circumferential ridges  108   a ,  108   b  that define a groove  110  therebetween, as shown in  FIG.  4   . In some embodiments, a gasket, such as, for example, an O-ring similar to O-ring  76  is positioned in groove  110  such that outer surfaces of ridges  108   a ,  108   b  and/or the O-ring in groove  110  form an air tight and/or water tight seal with surface  68  when plunger  96  is positioned within lumen  72 . 
     In some embodiments, plunger  96  includes a valve, such as, for example, a vent valve or a check valve  112  ( FIGS.  9 ,  10  and  13 - 16   ) to allow air within passageway  32  and/or lumen  72  to exit plunger  96  when plunger  60  and/or plunger  96  are inserted into passageway  32 , as discussed herein. Valve  112  includes a cavity  114  and a washer  116  that is positioned at the bottom of cavity  114 . Washer  116  includes an opening  118  that extends through the thickness of washer  116  such that opening  118  is in communication with cavity  114 . In some embodiments, opening  118  may have various cross section configurations, such as, for example, circular, oval, oblong, triangular, rectangular, square, polygonal, irregular, uniform, non-uniform, variable, tubular and/or tapered. In some embodiments, washer  116  is assembled onto tip  104  using ultrasonic welding or adhesive, for example. In some embodiments, washer  116  monolithically and/or integrally formed with tip  104 . Cavity  114  includes a first portion  114   a  and a second portion  114   b  positioned above portion  114   a . Portion  114   a  has a maximum diameter that is greater than a maximum diameter of portion  114   b . In some embodiments, cavity  114  includes a tapered portion between portion  114   a  and portion  114   b . In some embodiments, cavity  114  extends through a top surface  102   b  of flange  102 , as shown in  FIG.  9   . In some embodiments, cavity  114  terminates before flange  102 , such that cavity  114  does not extend through top surface  102   b  of flange  102 , as shown in  FIG.  10   . Valve  112  includes a ball, such as, for example a check ball  120  movably positioned within portion  114   a  of cavity  114 . In embodiments wherein cavity  114  does not extend through top surface  102   b  of flange  102 , valve  112  includes a vent hole  122  having a first end  122   a  that is in communication with portion  114   b  of cavity  114 , as shown in  FIG.  13    and a second end  122   b  that extends through an outer surface of body  106  to allow air in lumen  72  and/or passageway to enter cavity  114  and exit plunger  96  through vent hole  122 , as discussed herein. Ball  120  has a maximum diameter that is greater than the diameter of opening  118  and the diameter of portion  114   b  of cavity  114  to allow ball  120  to completely block opening  118  and portion  114   b , as discussed herein. 
     Valve  112  is movable between a first position, shown in  FIG.  13    a second position, shown in  FIG.  15   , and a third position shown in  FIG.  16   . In particular, gravity will cause a portion of ball  120  to be positioned within opening  118  such that ball  120  completely blocks or closes opening  118 , as shown in  FIG.  13   . When plunger  96  is moved axially relative to extension  16  and/or plunger  60  in the direction shown by arrow A in  FIG.  2   , air within passageway  32  of extension  16  and/or lumen  72  of plunger  60  will move ball  120  upwardly within cavity  114  toward portion  114   b  of cavity  114  such that ball  120  floats within portion  114   a  of cavity  114 , as shown in  FIG.  15   , to allow the air to move around ball  120  and into portion  114   b  of cavity  114 . The air then moves out of portion  114   b  through vent hole  122  such that the air exits plunger  96  through end  122   b  of vent hole  122 . This allows the air to move into a portion of lumen  72  that is positioned above tip  104  such that the air can move into the environment surrounding system  10  through a proximal opening in lumen  72 . When a material, such as, for example material M moves into portion  114   a  of cavity  114  through opening  118 , material M moves ball  120  upwardly within cavity  114  toward portion  114   b  of cavity  114  such that ball  120  seats within tapered portion  114   c  of cavity  114  and blocks material M from moving into portion  114   b  of cavity  114 , as shown in  FIG.  16   . In some embodiments, end surface  20  of base  14  includes a central protrusion  20   a , as shown in  FIGS.  9  and  10   , Protrusion  20  is positioned within opening  118  when plunger  60  is fully inserted into extension  16  and plunger  96  is fully inserted into plunger  60 . 
     In some embodiments, plunger  96  includes spaced apart struts  124  that each extend continuously from tip  104  to flange  102 . Struts  124  are disposed radially about body  106 . In some embodiments, struts  124  are evenly spaced apart from one another. Struts  124  each have a convexly curved outer surface. The outer surfaces of struts  124  are continuously curved along the length of struts  124  and conform to the curvature of surface  68  of plunger  60  such that the outer surfaces of struts  124  directly engage surface  68  and form an air tight and/or water tight seal with surface  68  as plunger  96  translates axially in opposite directions within lumen  72 . Men the outer surfaces of struts  124  directly engage surface  68 , body  106  of plunger  96  is spaced apart from surface  68 ; as shown in  FIGS.  9  and  10   ; for example. 
     In operation and use, system  10  may be used to mix and/or dispense material M. In some embodiments, material M comprises a material, such as, for example, a liquid; gel, paste, cement, gum, ointment, cream and/or foam. In some embodiments, material M comprises a bone filler material, such as, for example, bone cement. In some embodiments, the bone cement comprises a poly(methyl methacrylate) (PMMA); methyl methacrylate (MMA); calcium phosphate; a resorbable polymer, such as, for example, PLA, PGA or combinations thereof; a resorbable polymer with allograft, such as, for example, particles or fibers of mineralized bone; Plexur® sold by Osteotech, Inc., or combinations thereof. In some embodiments, the bone cement is a high viscosity bone cement. In some embodiments, the bone cement has a viscosity that is at least 500 Pascal-sec (Pa-s) to infiltrate a medical site and prevent any migration of the bone cement during medical procedures. In some embodiments, the bone cement has a viscosity that is at least 600 Pa-s. In some embodiments, the bone cement has a viscosity that is at least 800 Pa-s. In some embodiments, the bone cement has a viscosity that is at least 1,000 Pa-s. In some embodiments, the bone cement comprises a liquid component and a powder component. In some embodiments, the liquid component and the powder component are mixed or otherwise combined such that the bone cement has a viscosity of at least 500 Pa-s at 2 minutes after the initiation of mixing the two components. In some embodiments, the liquid component and the powder component are mixed or otherwise combined such that the bone cement has a viscosity of at least 500 Pa-s at 5 minutes after the initiation of mixing the two components. In some embodiments, the liquid component and the powder component are mixed or otherwise combined such that the bone cement has a viscosity of at least 500 Pa-s after 10 minutes or more from the initiation of mixing the two components. In some embodiments, the bone cement comprises a polymerization accelerator. 
     Material M is inserted into passageway  32  such that material M is positioned at the bottom of passageway  32  and/or contacts end surface  20  of base  14 . Material M is inserted into passageway  32  when valve  52  is in the first orientation discussed above and shown in  FIGS.  1 - 3  and  12    such that valve  54  blocks channel  56 . In some embodiments wherein material M comprises multiple components, such as, for example, a liquid component and a powder component, the components of material M may be mixed prior to inserting material M into passageway  32 . The mixed material M may then be inserted into passageway  36 , as discussed herein. In some embodiments wherein material M comprises multiple components, such as, for example, a liquid component and a powder component, the components of material M may be mixed within passageway  32 , as discussed herein. In some embodiments, the components of may be mixed within passageway  32  or outside of passageway  32  using pressure, mechanical agitation, static mixing, or combinations thereof. 
     After material M is inserted into passageway  32 , tip  104  and body  106  of plunger  96  are inserted into lumen  72  of plunger  60 , as discussed herein, to form a plunger assembly. When plunger  96  is inserted into lumen  72  to form the plunger assembly, bottom surface  102   a  of flange  102  directly engages top surface  82   c  of flange  82 , as discussed herein and shown in  FIG.  2   . When plunger  96  is inserted into lumen  72 , the outer surface of tip  104  and/or an O-ring that is positioned within groove  110  directly engages surface  68  of plunger  60  to form an air tight or water tight seal with surface  68 , as discussed herein. The plunger assembly is inserted into passageway  32  such that end surface  62  of plunger  60  is spaced apart from end surface  20  of base  14  that defines the bottom of passageway  32 , as shown in  FIG.  2   . When the plunger assembly is inserted into passageway  32 , outer surfaces of lips  74   a ,  74   b  and/or O-ring  76  of plunger  60  form an air tight and/or water tight seal with surface  30  of extension  16 , as discussed herein. As the plunger assembly is inserted into passageway  32 , air within passageway  32  can escape through valve  112  of plunger  96 , as discussed herein. In some embodiments, the plunger assembly is inserted into passageway  32  such that end surface  62  of plunger  60  touches material M. In some embodiments, the plunger assembly is inserted into passageway  32  such that end surface  62  of plunger  60  is spaced apart from material M, as shown in  FIG.  2   . In some embodiments, the amount that the plunger assembly is inserted into passageway  32  depends upon the volume of material M within passageway  32 . For example, the plunger assembly may be inserted farther into passageway  32  when the volume of material M within passageway  32  is less. However, when the volume of material M within passageway  32  increases, the plunger assembly is not inserted into passageway as far. 
     Plunger  60  is moved axially relative to main body  12  and plunger  96  within passageway  32  in the direction shown by arrow A in  FIG.  2    such that end surface  62  of plunger  60  engages the wall that defines the bottom of passageway  32 , as shown in  FIG.  3   . When end surface  62  of plunger  60  engages the wall that defines the bottom of passageway  32 , plunger  60  is fully seated within passageway  32 . In some embodiments, plunger  60  is connected with extension  16  by forming moving the twist lock discussed herein and shown in  FIGS.  7 - 11    from the unlocked position to the locked position to fix plunger  60  relative to extension  16  such that plunger  60  is prevented from moving axially relative to extension  16 . In some embodiments, plunger  60  is connected with extension  16  using cap  86 , as discussed herein, to fix plunger  60  relative to extension  16  such that plunger  60  is prevented from moving axially relative to extension  16 . As plunger  60  moves relative to main body  12  and plunger  96  in the direction shown by arrow A, material M moves into lumen  72  of plunger  60 , as shown in  FIGS.  3  and  4   . Because lumen  72  has a smaller diameter than passageway  32 , the same amount of input force creates more pressure on material M than would be created if lumen did not extend through end surface  62  of plunger. This amplification of pressure means that less effort is needed in dispensing material M. In some embodiments, plunger  60  is moved relative to main body  12  and plunger  96  in the direction shown by arrow A until bottom surface  82   a  of flange  82  of plunger  60  directly engages top surface  28   a  of flange  28  of extension  16 , as discussed herein and shown in  FIG.  3   . As plunger  60  is moved relative to main body  12  and plunger  96  in the direction shown by arrow A, flange  102  of plunger  96  becomes spaced apart from flange  82  of plunger  60 , as shown in  FIGS.  3  and  4   . 
     Valve  52  is moved from the first orientation, shown in  FIGS.  1 - 3 ,  7 ,  8  and  12   , in which valve body  54  blocks channel  56  to the second orientation, shown in  FIGS.  4 - 6   , by rotating valve body  54  relative to fitting  40  such that channel  56  is aligned with opening  38  and duct  48 , as discussed herein and shown in  FIG.  4   . In some embodiments, cap  86  is coupled to extension  16  and plunger  60  such that surface  94  of part  88  engages surface of part  90  and flanges  28 ,  82  are disposed in cavities  95  of parts  88 ,  90  to fix plunger  60  relative to main body  12 , as discussed herein. In some embodiments, part  88  remains removably coupled to part  90  after flanges  28 ,  82  are disposed in cavities  95 . In some embodiments, part  88  may be permanently joined with part  90  by applying an adhesive to one or both of surfaces  94 , for example. 
     After valve  52  is moved from the first orientation to the second orientation, plunger  96  is moved axially relative to main body  12  and plunger  20  in the direction shown by arrow A such that tip  104  of plunger  96  pushes material M out of lumen  72  and through opening  38 , channel  56  and duct  48 , as shown in  FIG.  5   . Plunger  96  may be moved axially relative to main body  12  and plunger  20  until bottom surface  102   a  of flange  102  directly engages a top surface  82   c  of flange  82 , as also shown in  FIG.  5   , so as to push all of material M out of lumen  72  and through opening  38 , channel  56  and duct  48 . In some embodiments, syringe  44  may be coupled to hub  42  of fitting  40  prior to moving plunger  96  axially relative to main body  12  and plunger  60  such that material M moves out of lumen  72 , through opening  48  and into syringe  44  when plunger  96  is moved axially relative to main body  12  and plunger  20 , as shown in  FIG.  6   . A medical practitioner may then remove syringe  44  from hub  42  and inject material M from syringe  44  and into hole(s), fracture(s), void(s), depression(s), etc. in bone to fill the same, at least partly, with material M to maintain or improve the bone&#39;s structural integrity. 
     In some embodiments, system  10  may be used as a single stage plunger. In such embodiments, material M is inserted into passageway  32  such that material M is positioned at the bottom of passageway  32  and/or contacts end surface  20  of base  14 . The plunger assembly is then inserted into passageway  32 . As the plunger assembly is inserted into passageway  32 , air within passageway  32  of extension can exit passageway  32  through valve  112  of plunger  96 , as discussed herein. The plunger assembly then pushes material M through opening  38 , channel  56  and duct  48 . In some embodiments, syringe  44  may be coupled to hub  42  of fitting  40  prior to moving the plunger assembly relative to main body  12  such that material M moves through opening  48  and into syringe  44  when the plunger assembly is moved axially relative to main body  12  and plunger  20 A medical practitioner may then remove syringe  44  from hub  42  and inject material M from syringe  44  and into hole(s), fracture(s), void(s), depression(s), etc. in bone to fill the same, at least partly, with material M to maintain or improve the bone&#39;s structural integrity. 
     In some embodiments, a kit containing one or more components of dispensing system  10  is provided. The kit may include components from any of the embodiments discussed herein. In some embodiments, material M is bone cement, as discussed herein, and the kit includes instructions for mixing and/or dispensing the bone cement using the contents of the kit. 
     Example 1 
     A two-stage mixer plunger, similar to the device of system  10  discussed herein was tested to determine the difference in force required to plunge the plunger for plunging bone cement. The test was conducted at 18° C. The two-stage mixer plunger includes a bayonet mount two stage plunger that clips onto a mixer of the two-stage mixer plunger. The two-stage mixer plunger used in this test is the same as the embodiments discussed herein that do not include cap  86 , such as, for example, the embodiments wherein flanges  28 ,  82  form a twist lock, as discussed herein. The two-stage mixer plunger performed as follows: 
     
       
         
           
               
            
               
                   
               
               
                 Two-Stage Mixer Plunger (Bayonet) 
               
            
           
           
               
               
               
            
               
                 Time 
                 Force (lb) 
                 Volume dispensed (running total) 
               
               
                   
               
               
                 2:00 
                 18 
                 1 
               
               
                 2:30 
                 13 
                 2 
               
               
                 3:00 
                 17 
                 3 
               
               
                 3:30 
                 20 
                 4 
               
               
                 4:00 
                 21 
                 5 
               
               
                 4:30 
                 28 
                 6 
               
               
                 5:00 
                 40 
                 N/A 
               
               
                   
               
            
           
         
       
     
     Example 2 
     A two-stage mixer plunger, similar to the device of system  10  discussed herein was tested to determine the difference in force required to plunge the plunger for plunging bone cement. The test was conducted at 18° C. The two-stage mixer plunger includes separate clips to hold the first stage plunger onto the mixer. The two-stage mixer plunger used in this test is the same as the embodiments discussed herein and shown in  FIG.  7    that include cap  86 . The two-stage mixer plunger performed as follows: 
     
       
         
           
               
            
               
                   
               
               
                 Two-Stage Mixer Plunger (Clips) 
               
            
           
           
               
               
               
            
               
                   
                   
                 Volume dispensed  
               
               
                 Time 
                 Force (lb) 
                 (running total) 
               
               
                   
               
            
           
           
               
               
               
            
               
                 2:00 
                 21 
                 1.5 
               
               
                 2:30 
                 11 
                 2.25 
               
               
                 3:00 
                 16 
                 3 
               
               
                 3:30 
                 21 
                 4 
               
               
                 4:00 
                 26 
                 5 
               
               
                 4:30 
                 38 
                 6 
               
               
                 5:00 
                 41 
                 7 
               
               
                 5:30 
                 52 
                 8 
               
               
                   
               
            
           
         
       
     
     It will be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the above description should not be construed as limiting, but merely as exemplification of the various embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.