US20020191487A1 - Systems and methods for mixing and transferring flowable materials - Google Patents

Abstract

A device for mixing and transferring a bone filling material is provided. The device includes a receptacle for receiving components in an unmixed condition. A mixing element insertable into the receptacle to mix the components is provided, as well as an actuator having a drive member and a driven member, the actuator being removably coupled to the mixing element.

Description

RELATED APPLICATION
• This application claims the benefit of United States provisional application Serial No. 60/243,195 filed Oct. 25, 2001.[0001]
FIELD OF THE INVENTION
• The invention relates to systems and methods for mixing materials together and transferring the materials into other instruments, particularly for use in the medical field.[0002]
BACKGROUND OF THE INVENTION
• Current methods and apparatus for mixing a plurality of materials together in the medical field, e.g., poly (methyl methacrylate) bone cement comprising a powdered material with a liquid monomer to be used as a bone filling material, often yield unsatisfactory results.[0003]
• Typically, in a surgical setting, the instruments employed for this purpose are a small bowl for receiving the components and a stick (such as a common tongue depressor) for mixing the components in the bowl. If a powdered material is employed, it is usually poured directly from its container into the bowl. Consequently, the process is often messy due to spillage of the powdered material. Where one of the components is a liquid monomer, the process can involve the release of noxious fumes released by the liquid monomer.[0004]
• After the components are mixed, as in the case of a bone filling material, further problems are encountered. When the bone filling material is to be dispensed into a cavity in bone, the common practice is to first transfer the material into a syringe and then to transfer the material into the instrument for delivery to the cavity. The syringe is loaded by either vacuuming up the material by withdrawing the fully engaged plunger through the syringe body, or by removing the syringe plunger and pouring the material into the back of the syringe and reinserting the plunger. This is a difficult and messy procedure. Thus, there is a need for providing a way of mixing materials while containing the fumes and to easily and cleanly transfer or dispense the contents into other instruments.[0005]
SUMMARY OF THE INVENTION
• Although various manufacturers of medical products have attempted to develop, manufacture and supply various systems for mixing and/or dispensing poly (methyl methacrylate) bone cement (e.g., DePuy—see PCT Publication No. WO97/21485, Immedica—see PCT Publication No. WO99/37256, and Stryker—see U.S. Pat. No. 6,042,262) such systems are often expensive, too complex, require extensive and/or externally-powered accessories, or cannot mix small quantities of bone filler material. Because of these and other problems, there is a need for improved systems and methods for mixing and transferring materials, particularly in the medical field.[0006]
• One aspect of the invention provides hand-held systems and associated methods for using the systems, which accurately measure the components before mixing, contain the components during mixing, mechanically mix or stir the bone filling material, and conveniently and cleanly transfer or dispense the mixture into other instruments. The hand-held system provides a simple, quick and cost-effective way to mix and transfer materials.[0007]
• Another aspect of the invention provides hand-held systems and associated methods for using the systems which fully contain the components during mixing (desirably eliminating any spillage of noxious fumes released during mixing).[0008]
• One aspect of the invention provides an assembly that includes a receptacle for receiving components, e.g., of a bone filling material, in an unmixed condition. The assembly also includes a mixing element that is insertable into the receptacle to mix the components. The assembly further includes an actuator for the mixing element, including a drive member and a driven member coupled to the drive member. The actuator is removably coupled to the mixing element. After thorough mixing, the mixing element can be removed and/or a plunger is inserted into the receptacle to transfer or dispense the mixture.[0009]
• In one embodiment, the mixing element comprises a paddle that mixes components in response to rotation. The paddle can include a structure to promote mixing of components, such as, e.g., a plurality of apertures. In this arrangement, the actuator includes a drive member that rotates a paddle. The actuator can include a drive train, e.g., a planetary gear train, that couples a drive member to a driven member. Desirably, the drive member is operable manually, such that no external power source is required.[0010]
• In one embodiment, the receptacle comprises a dispensing valve. The dispensing valve is closed during the mixing step and is manually operated to open and close when performing the transferring or dispensing step.[0011]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIGS. 1A and 1B are plane views of various embodiments of a kit that contains the component parts of systems for mixing and dispensing flowable materials that embody features of the invention;[0012]
• FIGS. 2A and 2B are perspective views of various embodiments of receptacles that form a part of the system shown in FIGS. 1A and 1B;[0013]
• FIG. 3 is a perspective view of a stand that forms a part of the system shown in FIG. 1A;[0014]
• FIG. 4 is perspective side view of an actuator that can form a part of the systems shown in FIGS. 1A and 1B;[0015]
• FIGS.[0016]4A-4F are perspective side views of alternate embodiments of actuator handle designs;
• FIG. 5A is a bottom view of the actuator shown in FIG. 4;[0017]
• FIG. 5B is a bottom view of an alternate embodiment of an actuator;[0018]
• FIG. 6A is an exploded, perspective view of the actuator shown in FIG. 4;[0019]
• FIG. 6B is an exploded, perspective view of an alternate embodiment of an actuator;[0020]
• FIG. 7 is a perspective view of one embodiment of a mixing element that forms a part of the system shown in FIGS. 1A and 1B;[0021]
• FIG. 8 is a perspective view of another embodiment of the mixing element that forms a part of the system shown in FIGS. 1A and 1B;[0022]
• FIG. 9 is a perspective view of another embodiment of the mixing element that forms a part of the system show in FIGS. 1A and 1B;[0023]
• FIG. 10 is a perspective view of the receptacle shown in FIG. 2 inserted into the stand shown in FIG. 3, and also showing a component being added to the receptacle;[0024]
• FIG. 11 is a perspective view of the proximal end of the mixing element shown in FIG. 8 inserted into the exterior side of the lower half of the actuator shown in FIG. 4;[0025]
• FIG. 12 is an exploded view of the actuator, mixing element, receptacle, and stand assembly, as also shown in assembled view in FIG. 13;[0026]
• FIG. 13 is a perspective view of the assembly shown in FIG. 12, showing the actuator grasped by one hand and being manually rotated, and showing the receptacle being grasped by the other hand of the operator, the rotation of the actuator serving to mix materials in the receptacle;[0027]
• FIG. 14 is a perspective view showing the plunger being inserted into the receptacle after the materials have been mixed in the receptacle;[0028]
• FIG. 15 is a perspective view showing the stand being removed from the receptacle prior to dispensing material from the receptacle;[0029]
• FIG. 16 is a perspective view of the plunger inserted into the receptacle containing the material, which is now ready to be dispensed;[0030]
• FIG. 17 is a perspective view of the material mixed within the receptacle being dispensed from the receptacle;[0031]
• FIG. 18 is a bottom view of the upper half of the actuator that forms part of the system shown in FIG. 1B;[0032]
• FIG. 19 is a perspective view of the plunger assembly showing an opening for an air purge valve;[0033]
• FIG. 20 is a perspective view of one embodiment of a dispenser valve with an assembly for securing to the receptacle of FIG. 2B;[0034]
• FIG. 21 is a perspective view of the receptacle of FIG. 2B with an optional attached vacuum line; and[0035]
• FIG. 22 is a partially cut-away view of the receptacle of FIG. 21;[0036]
• FIG. 23 is another partially cut-away view of the receptacle of FIG. 21;[0037]
• FIG. 24A is a perspective view of an embodiment of a collapsible mixing element suited for use in the receptacle of FIG. 21;[0038]
• FIG. 24B is a side view of the collapsible mixing element of FIG. 24A;[0039]
• FIG. 25 is a perspective view of another embodiment of a collapsible mixing element suited for use in the receptacle of FIG. 21;[0040]
• FIG. 26 is a perspective view of another embodiment of a collapsible mixing element suited for use in the receptacle of FIG. 21.[0041]
DETAILED DESCRIPTION OF THE EMBODIMENTS
• The embodiments describe systems and methods that embody features of the invention in the context of mixing a bone filling material. It should be appreciated, however, that the systems and methods so described are not limited in their application to the mixing of bone filling material. The systems and methods are applicable for use in diverse applications, both inside and outside the medical field.[0042]
• It should also be appreciated that the various component parts of the inventions described herein can be comprised of non-ferrous and/or non-metallic materials, which would permit the various embodiments to be utilized in a magnetic and/or whole room MRI environment.[0043]
I. THE COMPONENT PARTS
• FIG. 1A shows component parts, arranged as a[0044]kit200, that are usable in association with each other to form a material mixing and transferring system. The number and structure of the component parts can vary. In FIG. 1A, thekit200 includes areceptacle12 for receiving materials for mixing and for, after mixing, transferring or dispensing the materials astand14 for receiving thereceptable12; a mixingelement16 that can be inserted into thereceptacle12 to mix the materials; anactuator18 to drive the mixingelement16; aplunger20 that can be inserted into thereceptacle12 to urge mixed materials from thereceptacle12; a dispensingelement22 to dispense the mixed materials urged from thereceptacle12; and a measuringdevice24 to measure materials placed in thereceptacle12 for mixing.
• Desirably, the[0045]components12,14,16,18,20,22 and24 comprise a substantially rigid metal, plastic or ceramic material. In one embodiment, thecomponents12,14,16,20,22 and24 comprise polypropylene, andcomponent18 comprises Acetal homopolymer (DELRIN® material from DuPont Corporation) or a clear or colored nylon. The component materials will desirably be unaffected by contact with the bone filler material and/or sterilizable by gamma radiation. Of course, various other alternative materials can be used, including materials which are capable of withstanding contact with monomer without significant degradation for limited periods of time.
• A. The Receptacle[0046]
• As shown in FIG. 2A, the[0047]receptacle12 has aproximal end30 and adistal end32. Thereceptacle12 further has aninterior bore37 which desirably extends from theproximal end30 to thedistal end32. Thedistal end32 carries adistal tip34, through which one may dispense a material such as a bone filling material.
• The[0048]receptacle12 is sized to separately accommodate the mixingelement16 and theplunger20 at different stages of use. The interior surface of thedistal tip34 is sized to support thedistal tip62 of the mixingelement16 during use, as will be described in greater detail later. Theproximal end30 carries a set oftabs36 on anouter surface33 of thereceptacle12, to couple the receptacle to theactuator18, which, in turn, releasably couples to theproximal end56 of the mixingelement16. When theplunger20 is inserted into thereceptacle12, thetabs36 also allow the physician to grasp and operate thereceptacle12 andplunger20 like a syringe, for dispensing materials after mixing, as will be described later.
• In one embodiment, the[0049]receptacle12 has a volume of approximately seventy cubic centimeters (70 cc). Of course,other size receptacles12 could be used, depending upon the size of the mixingelement16 and other associated components, and the desired amount of filler material to be mixed. Other representative sizes could include five (5) , ten (10) and twenty (20) cc syringes. Theouter surface33 of thereceptacle12 desirably includes a graduatedscale39 showing the volume inside thereceptacle12. Preferably, the graduatedscale39 begins near thedistal tip34 of thereceptacle12. Thereceptacle12 is desirably made of transparent polypropylene to allow viewing of the materials to be mixed when placed in thereceptacle12, during mixing and during transfer.
• In an alternate embodiment, as shown in FIG. 2B, the[0050]receptacle12 at thedistal end32 comprises areceptacle base35. Thereceptacle base35 is generally hemispherical in shape and supports the interior bore37 of thereceptacle12. Within the interior bore37 of thereceptacle12, at thereceptacle base35, is located a central neck (not shown) that is sized to accept and to securely hold thedistal tip62 of the mixingelement16, as previously described in connection with the previous embodiment. Thereceptacle base35 desirably stabilizes and elevates the interior bore37 and allows for easier dispensing or transfer of the mixed material. Thereceptacle base35 is sized to provide a solid footing to minimize tipping of thereceptacle12. Thereceptacle12 has an outlet34B for dispensing the mixed bone filling material.
• If desired, the[0051]receptacle12 may incorporate a vacuum attachment31 (see FIG. 2B) for a standard operating room suite vacuum hose, to evacuate fumes in thereceptacle12 and/or degas the material. The vacuum hose may be further secured by an indent31A in thereceptacle base35. If further desired, thereceptacle12 may form a cartridge for a bone filling material delivery gun.
• B. The Stand[0052]
• In the system shown in FIG. 1A, the stand[0053]14 (see FIG. 3) supports thereceptacle12 during mixing. Thestand14 has anupper side40 and alower side42. Theupper side40 has acentral neck44 that is sized to accept and to securely hold thedistal end32 of thereceptacle12. Centered within theneck44 is asmall chamber46 that is sized to accept thedistal tip34 of thereceptacle12. Thelower side42 of thestand14 has a flat surface which allows thestand14 to sit evenly on a surface such as a treatment table.
• A[0054]separate stand14 is not absolutely necessary for the system shown in FIG. 1B as thereceptacle base35 is incorporated directly into thereceptacle12.
• C. The Mixing Element[0055]
• The mixing[0056]element16 can be variously configured, and FIGS. 7, 8 and9 show different representative configurations. In use, the mixingelement16 rotates within thereceptacle12 to mix the materials contained in the receptacle.
• In the various described configurations, the mixing[0057]element16 has anupper side50 and alower side52. In these embodiments, the upper andlower sides50 and52 can have an outwardly extendingcentral rib51 that acts as a stiffener to maintain integrity of the mixingelement16. The mixingelement16 may also include one or more crosswiseribs53.
• The mixing[0058]element16 has aproximal end56 and adistal end57. Thedistal end57 desirably carries aflat tip62 that is adapted to fit into thedistal tip34 of thereceptacle12. Thedistal tip62 of the mixingelement16 desirably mixes the components located in thedistal tip34 of thereceptacle12. Thedistal tip62 also desirably acts as a bearing surface within thedistal tip34 of thereceptacle12, to keep the mixingelement16 centered within thereceptacle12 as it rotates, as well as constraining side-to-side movement of the mixingelement16 within thereceptacle12. Thedistal tip62 also acts to maintain secure engagement of the mixingelement16 to theactuator18
• If desired, the[0059]proximal end56 can carry a solidcylindrical tip58, although theproximal end56 could be various configurations suitable for attachment to theactuator18. Thetip58 is adapted to couple to theactuator18, as will be described in greater detail later. Thetip58 has acrosspiece60 that facilitates the transmission of rotational forces from theactuator18 to the mixingelement16 as shown in FIGS. 7, 8 and9. Thecrosspiece60 also acts to firmly engage the mixingelement16 with thekeyway89 of theactuator18 by snapping in place. Thetip58 may also containridges59 as shown in FIG. 9 to impart further strength and stability.
• The mixing[0060]element16 also desirably has one ormore apertures61,63,65,67,68, and69, as shown in FIGS.7-9. Theapertures61,63,65,67,68, and69 function to assist in mixing the chosen components, such as a powdered material and a liquid monomer, together. Theapertures61,63,65,67,68, and69 are desirably large enough to allow some of the mixture to flow through the mixingelement16, thereby allowing the mixingelement16 to rotate within thereceptacle12 with a minimum of resistance and maximizing the mixing of the chosen mixing materials. If the sizes of theapertures61,63,65,67,68, and69 are increased, less resistance to rotation is noted. However, there is a concomitant need for additional rotation of the mixingelement16 in the mixture to ensure thorough mixing. Larger apertures ease the mixing process, while smaller apertures may result in the components “riding up” the mixingelement16. In such a case, the mixing must be stopped momentarily in order to allow the components to fall back into the mixture.
• Desirably, the mixing[0061]element16 is sized to extend substantially across the interior of thereceptacle12. Such an arrangement can facilitate mixing of the powder and liquid components, because rotation of the mixingelement16 can “scrape” the powdered and liquid components off the inner walls of the receptacle, ensuring even mixing of the components. While actual physical contact between the side walls of thereceptacle12 and the mixingelement16 are not absolutely necessary, in least one embodiment the mixingelement16 and the side walls of thereceptacle12 are in very close proximity.
• In the embodiment shown in FIG. 8, the mixing[0062]element16 desirably has a series of small, evenly spacedapertures65 beginning near theproximal end56 of the mixingelement16, followed by at least twolarge apertures69 extending toward thedistal end57 of the mixingelement16, and at least two intermediatesized apertures67 at thedistal end57. Such an embodiment allows for easier mixing and minimizes the previously mentioned “riding up” of the mixture; however, this embodiment typically requires additional rotations of theactuator18. In this embodiment approximately five to twenty rotations of theactuator18 should be sufficient to ensure a proper mixture in the case of a bone filling material.
• In the embodiment shown in FIG. 7, the mixing[0063]element16 has a plurality of evenly spacedapertures61 that are positioned parallel to therib51, and the mixingelement16 further has at least twoapertures63 at thedistal tip62. This embodiment requires approximately five to ten rotations of theactuator18 to mix a proper bone filling material. Although fewer rotations are needed with this embodiment, this embodiment typically requires more strength for the rotations on behalf of the operator than does the previously mentioned embodiment. Additionally, it is occasionally necessary to stop during the mixing process to allow the components to fall back into the mixture.
• In the embodiment shown in FIG. 9, the mixing[0064]element16 has twolarger apertures68 beginning near theproximal end58 of the mixingelement16, followed by at least twolarge apertures69 extending toward thedistal end57. This embodiment requires approximately fifteen to twenty rotations of theactuator18 to properly mix the bone filling material. The minimal surface area of the mixingelement16 as shown in FIG. 9 allows only a small amount of bone filler material to be retained on the mixingelement16 when it is removed from thereceptacle12 after thorough mixing.
• In other alternative embodiments, the mixing[0065]element16 could incorporate any number of apertures of various sizes and shapes (not shown).
• D. The Actuator[0066]
• The actuator[0067]18 (see FIGS. 4 and 5A and5B) drives the mixingelement16. Desirably, theactuator18 is formed from DELRIN® material or a clear or colored nylon. As shown in FIG. 4, theactuator18 is in a palm-sized, cylindrical shape.
• The[0068]actuator18 has anouter surface70 that, if desired, may be knurled or indented to facilitate gripping by the user. FIGS.4A-4F show various alternative handle designs for an actuator. Theactuator18 has anupper half72 and a lower half74 (see also FIGS. 6A and 6B) that are adapted to be connected together in various ways, including fasteners, adhesives, or a snap-fit.
• The[0069]upper half72 of the actuator18 functions as a drive member, while thelower half74 of theactuator18 is a driven member. Theupper half72 rotates relative to thelower half74.
• Both the[0070]upper half72 and thelower half74 of theactuator18 have aninterior side76 and anexterior side78. As shown in FIG. 6A, theinterior side76 of theupper half72 contains aring gear73. Theinterior side76 of thelower half74 contains a planetary gear arrangement84 that meshes with thering gear73.
• The planetary gear arrangement[0071]84 includes asun gear86 and one or more planet gears88. Thesun gear86 is fixed axially to thelower half74 of theactuator18 by means of ascrew95. The planet gears88 are fixed to aretainer ring92 byscrews94. In one alternative embodiment, the planet gears88 would comprise two gears, each gear positioned on opposite sides of thesun gear86.
• The teeth of the planet gears[0072]88 mesh with the teeth of thering gear73. The teeth of the planet gears88 also mesh with thesun gear86. Rotation of theupper half72 of theactuator18 relative to thelower half74 of theactuator18 rotates thering gear73. This, in turn, imparts rotation to the planet gears88 within the stationarylower half74 of theactuator18. Rotation of the planet gears88, in turn, rotates thesun gear86 within thelower half74 of theactuator18. In the embodiment where there are threeplanet gears88, a single rotation of the ring gear73 (i.e., theupper half72 of the actuator18) equals approximately four rotations of thesun gear86 within thelower half74 of theactuator18. In the embodiment where there are two planet gears88, a single rotation of thering gear73 equals approximately three rotations of thesun gear86.
• As shown in FIG. 5A, the[0073]exterior side78 of thelower half74 of theactuator18 has acentral slot96 which receives thecylindrical tip58 of the mixingelement16. Anaxle87 projecting from the sun gear86 (see FIG. 6A) extends into theslot96. Thecrosspiece60 on thetip58 fits into akeyway89 on the axle87 (see FIG. 5A), which couples the mixingelement16 to thesun gear86. Thus, rotation of thesun gear86 imparts rotation to the mixingelement16.
• Additionally, the[0074]exterior side78 of thelower half74 has stabilizing structure98 (see FIG. 5A). Thestructure98 abuts against and/or grips thetabs36 of thereceptacle12 to prevent thereceptacle12 from rotating while rotation is imparted by thesun gear86 to the mixingelement16. The stabilizingstructure98 is secured to thelower half74 of theexterior side78 byfasteners99. If desired, theactuator18 may incorporate an attachment for a standard operating room suite vacuum hose (not shown), to evacuate fumes within thereceptacle12.
• In an alternate embodiment (see FIG. 6B), the[0075]upper half72 of theactuator18 has anintegral ring gear73 adapted into the interior surface71 (see FIG. 18) of theactuator18. Thelower half74 of theactuator18 has a planetary gear arrangement84 that meshes with thering gear73. The planetary gear arrangement84 includes asun gear86 and a plurality of planet gears88. Desirably, theplanetary gear arrangement88 comprises two planet gears88. Thesun gear86 is fixed axially to thelower half74 of theactuator18 by means of anaxle87. Theaxle87 is adapted at the top to snap-fit with theupper half72 and is adapted at the bottom to receive thetip58 of the mixingelement16. The middle section of theaxle87 is squared off to hold thesun gear86 in place and to receive rotational forces imparted by thesun gear86.
• The planet gears[0076]88 are fixed to thelower half74 of theactuator18 by hollow gear posts93. Theretainer ring92 hasretention tabs90 which fit through the central bore of the planet gears88 and extend into the hollow gear posts93 (see FIG. 6B) . Theretention tabs90 have small tangs extending downward through the hollow gear posts93 to securely engage theretainer ring92 to thelower half74 of theactuator18. Theretainer ring92 also desirably hasstabilizer feet97 extending downward to provide strength and stabilization to the planetary gear arrangement84.
• As shown in FIG. 5B, the[0077]exterior side78 of thelower half74 of theactuator18 has a stabilizing structure98B which is generally oblong to accommodate insertion of thereceptacle12. The oblong shape of the stabilizing structure98B prevents thereceptacle12 from rotating while rotation is imparted by thesun gear86 to theaxle87 which couples to the mixingelement16.
• E. The Plunger[0078]
• The plunger[0079]20 (see FIGS. 14 and 16) fits into thebore37 of thereceptacle12. Advancement of theplunger20 within thereceptacle12 desirably expels air from thereceptacle12, as well as dispenses material from thereceptacle12.
• As shown in FIG. 19 the[0080]plunger20 may also desirably contain one ormore openings103 for a valve that automatically purges the air in thereceptacle12 between theplunger20 and mixed bone filling material. Theplunger20 can contain aseal101 made from various materials including, but not limited to, a non-rigid material that is unaffected by contact with the mixed bone filling material. In one embodiment, theplunger20 can contain a valve with a small ball bearing (not shown) which allows air to escape as theplunger20 is advanced through thereceptacle12. The ball bearing (not shown) may be made from a plastic material that is less dense than the bone filling material. As theplunger20 contacts the viscous bone filling material, the ball bearing is forced up into a closed position. Purging the air allows for direct contact between theplunger20 and material, which provides for improved dispensing control of the material.
• F. The Dispensing Element[0081]
• In the system shown in FIG. 1A, the dispensing[0082]element22 comprises anozzle100 that is adapted to fit on thedistal tip34 of the receptacle12 (see FIG. 17). In another embodiment, a LUER® fitting (not shown) is incorporated into thedistal tip34 of thereceptacle12. In another embodiment, a fitting (not shown) is incorporated into thedistal tip34 of thereceptacle12, the fitting being adapted to mate with the body of a 5 cc or 10 cc syringe. In another embodiment, tubing (not shown) is incorporated into thedistal tip34 of thereceptacle12, the tubing being adapted to fit within a 5 cc or 10 cc syringe body.
• In the system shown in FIG. 1B, the dispensing[0083]element22 desirably snap fits onto thedistal end32 of thereceptacle12 by means of clips121 (see FIG. 20). The dispensingelement22 may also be attached to thereceptacle12 by other means, such as with adhesive, welding or by other means known in the art. The dispensingelement22 desirably mates with the outlet34B of the receptacle12 (see FIG. 2B) . A stopcock valve (not shown), or other type of suitably valve, can be located inside thevalve body125 and have aoutlet127 for the mixed material. The dispensingelement22 can have one or more dispensing handles123 located at the end(s) of thevalve body125. Two dispensing handles123, as shown in FIG. 20, can allow for either right- or left-handed operation of the dispensingelement22. A LUER® fitting129 is desirably incorporated onto thevalve body125, to facilitate attachment of a syringe or threaded bone filling device. Of course, any number of other types of fittings or tubings could be incorporated onto thevalve body125, depending upon the type of instrument receiving the transferred mixed material.
• G. The Measuring Device[0084]
• The measuring device[0085]24 (see FIG. 1A) is used to measure components before placing the components into the receptacle for mixing. The measuringdevice24 may be of a fixed size, such as a 10 cc measuring cup, may be graduated, and/or may include a sieve for sifting particles before mixing.
• H. The Funnel[0086]
• The[0087]funnel10 is used to facilitate placing or pouring of the components to be mixed into the receptacle12 (see FIG. 1B).
II. ILLUSTRATIVE USE OF THE SYSTEM
• In the embodiment shown in FIG. 1A, the[0088]receptacle12, stand14, mixingelement16,actuator18,plunger20,dispenser22 and the measuringdevice24, as well as the components to be mixed, are gathered together for use, or are withdrawn as needed from thekit200. The physician or an assistant inserts thedistal end32 of thereceptacle12 into theneck44 of theupper side40 of the stand14 (see FIG. 10). Desirably, thedistal tip34 of thereceptacle12 is held within thesmall chamber46 located on theupper side40 of thestand14, desirably sealing thedistal tip34 closed.
• As FIG. 20 shows, the physician may use the measuring[0089]device24 to measure a component to be mixed, such as a powdered component for poly(methyl methacrylate) bone cement. The powdered component is poured into thereceptacle12. If thereceptacle12 bears a graduatedscale39 on itsouter surface33, the component can be added to thereceptacle12 until the desired level is reached. After the powdered component is added to thereceptacle12, another component, such as a liquid monomer for bone cement, is added.
• The mixing[0090]element16 andactuator18 are then obtained. Desirably, theproximal end56 of the mixingelement16 has been inserted into theslot96 located on theexterior side78 of thelower half74 of the actuator18 (as FIG. 11 shows). The assembly is now inverted and thedistal end57 of the mixingelement16 inserted into theproximal end30 of the receptacle12 (shown in exploded view in FIG. 12). Desirably, the mixingelement16 is inserted such that thedistal tip62 of the mixingelement16 extends into thedistal tip34 of thereceptacle12. Theactuator18 desirably engages with thetabs36 located on theproximal end30 of thereceptacle12, so that thelower half74 of theactuator18 remains stationary relative to thereceptacle12.
• The physician now grasps the[0091]upper half72 of theactuator18 with one hand, while holding thestand14, thereceptacle12 or thestand14 andreceptacle12, with the other hand (see FIG. 13). Theupper half72 of theactuator18 is then rotated back and forth, first clockwise and then counterclockwise, e.g. (or vice versa), by half-turns, relative to thereceptacle12. Alternatively, or in conjunction with this back and forth motion, , theactuator18 may be rotated in a single direction. Desirably, theactuator18 is rotated enough times to adequately mix the mixture.
• After the mixture is adequately mixed, the[0092]actuator18 and mixingelement16 are removed from thereceptacle12 and set aside. If desired, the mixingelement16 may be scraped against the top of thereceptacle12 to remove mixture clinging to theelement16, desirably returning such mixture to thereceptacle12. Next, theplunger20 is inserted into theproximal end30 of the receptacle12 (see FIG. 14). The assembly can now be safely inverted and thestand14 removed from receptacle12 (see FIG. 15). Desirably, thestand14 will not be removed from thereceptacle12 before the step of inserting theplunger20 and inverting the assembly. In such a case, the mixture, as in the case of a bone filling mixture, could easily flow out of the opening in thedistal tip34 of thereceptacle12.
• After the[0093]stand14 is removed from thereceptacle12, air can be expelled from thedistal tip34 of thereceptacle12 by advancing theplunger20 in the usual fashion of purging air from a syringe. The mixture may be dispensed directly from thereceptacle12 by advancing theplunger20. If desired, adispenser22 is fitted onto thedistal tip34 of thereceptacle12. In one embodiment, if thedispenser22 is anozzle100, the mixture is dispensed through thenozzle100. In another embodiment, if thedistal tip34 of thereceptacle12 incorporates a LUER® fitting, the LUER® fitting may mate with a bone filler device as disclosed in U.S. Pat. No. 6,241,734 (which is incorporated herein by reference). When the LUER® fitting is incorporated into thedistal tip34 of thereceptacle12, the combination allows for the direct filling of multiple bone filler devices. In another embodiment, if thedistal tip34 of thereceptacle12 incorporates a fitting that mates with a syringe body of a 5 cc or 10 cc syringe, the syringe may be filled with the mixture in thereceptacle12. In another embodiment, thedistal tip34 of thereceptacle12 may incorporate tubing which fits within a 5 cc or 10 cc syringe body, thus allowing the syringe to be back-filled from the plunger end. In such an embodiment, the tubing is inserted through the plunger opening of the syringe. The syringe is filled from its distal tip to its proximal end, the tubing being withdrawn as the syringe fills to a desired level.
• The system shown in FIG. 1B contains additional features with enhanced ease of use and fewer steps. The[0094]receptacle20 is packaged in thekit200 with the dispensingelement22 in the closed position. After gathering the system parts (receptacle12, mixingelement16,actuator18,plunger20 and funnel10) from the sealedkit200 as well as the material to be mixed, the physician or an assistant positions thefunnel10 within theproximal end30 of thereceptacle12 and pours the powdered component into thereceptacle12. If desired, additional powdered materials, such as sterile barium sulfate (to make the mixture radiopaque) or antibiotics (to prevent infection) may be added to thereceptacle12 before addition of the liquid monomer. The mixingelement16 andactuator18 are coupled together as previously described and inserted into thereceptacle12. Theactuator18 is positioned to engage with thetabs36 on theproximal end30 of thereceptacle12. The physician or an assistant now rotates theactuator18 to mix the material as previously described. The monomer fumes in thereceptacle12 may be desirably evacuated from thereceptacle12 by thevacuum hose attachment31. After the mixture is adequately mixed, theactuator18 and mixingelement16 are removed from thereceptacle12 and set aside. Next, theplunger20 is inserted into theproximal end30 of thereceptacle12. Air can be automatically purged from the system through theopenings103 in theplunger20. The residual air/monomer mixture may then be evacuated from the interior bore37 of thereceptacle12 by thevacuum hose attachment31, further reducing exposure of the physician or an assistant to the monomer fumes. The mixture is now ready to be transferred. Desirably, the mixed material is transferred directly to the bone filler device as disclosed in U.S. Pat. No. 6,241,734. This step eliminates the need for transferring the material to another device, such as a syringe, which would in turn be used to fill the device of U.S. Pat. No. 6,241,734. The mixture may be dispensed directly through the opened dispensingelement22 by pushing down on theplunger20. Alternatively, the flow of the mixture may be controlled by rotating the dispensing handles123 to open and close the stopcock valve (not shown).
• If a mixture of additional bone filler material is desired, or additional bone filler material is required after the initial mixture has hardened and/or become unusable, the used mixing element[0095]16 (having bone filler material thereon) may be removed from theactuator18 and replaced with anew mixing element16, allowing theactuator18 to be used to mix an additional batch of bone filler material. In such a case, thekit200 could contain asingle actuator18 and measuringdevice24, withmultiple receptacles12, stands14, mixingelements16,plungers20 and dispensingelements22 to allow mixing of multiple batches of bone filler material.
III. CLOSED CEMENT MIXING AND TRANSFER SYSTEM
• Where the release of fumes and/or vapors from a surgical material is undesirable for some reason, it may be advantageous to use a closed mixing and transfer system for the preparation and/or delivery of medical materials such as bone cement. For example, the fumes and/or vapors from the liquid monomer component of PMMA bone cements can have a very unpleasant smells and inhalation of these fumes may pose a significant health risk to various operating room personnel as well as the patient.[0096]
• In the case of bone cement comprising PMMA powder and liquid monomer components, the liquid monomer is typically sealed within a glass jar or ampoule prior to use while the powder is contained in a plastic bag. One example of such packaging is found with SimplexP® PMMA bone cement, commercially available from Howmedica Corporation. While the powdered component of such bone cement is generally inert and not prone to becoming airborne (unless sufficiently disturbed), the liquid monomer component has a very low vapor pressure and vaporizes readily in contact with air.[0097]
• Once a glass ampoule containing liquid monomer is opened (typicaly by breaking the frangible cap on the glass ampoule) the liquid monomer is exposed to the atmosphere and begins to vaporize immediately. Moreover, during the mixing process, the liquid monomer continues to vaporize and also outgasses from the liquid/powder mixture. Once mixing is completed, the monomer continues to outgas from the liquid/powdered mixture, until such time as the mixture is contained within an enclosed environment (such as a syringe or other closed dispensing device or when the mixture is placed within the patient's body). Unless the mixture is contained within an enclosed environment during substantially all of the steps of the mixing and delivery operation, therefore, a significant amount of vaporized monomer may be released to the operating room during mixing and dispensing of bone cement.[0098]
• FIGS. 22 and 23 depict an alternate embodiment of a cement mixing and transfer system which desirably minimizes the release of vaporized monomer to the operating room environment. In this embodiment, the[0099]receptacle12 incorporates amonomer dispensing body400. Themonomer dispensing body400 comprises a retainingclip405, acontainment tube410, a breakingelement415, acap420, asupply lumen425 and a vent lumen430. Desirably, the dispensing body is secured to thereceptacle12, with thesupply lumen425 and vent lumen430 communicating with the interior of thereceptacle12 through one or more openings (not shown) in the receptacle wall. The dispensingbody400 may be secured to the receptacle in various ways, including clips, adhesive, welding or by other methods known in the art.
• As shown in FIG. 23, a[0100]stationary seal448 desirably engages the upper opening of thereceptacle12 in an air-tight fashion, desirably sealing thereceptacle12 from the operating room environment. A slidingseal450 is desirably positioned below thestationary seal448 and within thereceptacle12. Theseseals448 and450 can comprise various known sealing materials, including latex rubber. Desirably, theseals448 will permit rotation of the mixingelement16 andaxle87 while maintaining a substantially air-tight seal between the receptacle contents and the atmosphere. In addition, the slidingseal450 can desirably be moved longitudinally within thereceptacle12. If desired, the sliding seal can incorporate an internal slot or opening (not shown), which permits the slidingseal450 to slide along the central axis of the mixingelement16 while maintaining a substantially air-tight seal with the mixingelement16.
• To prepare the bone cement mixture, a measured amount of powdered PMMA component is introduced into the[0101]receptacle12. The mixing element and actuator are then attached to the receptacle, with theseals448 and450 sealingly engaging thereceptacle12. A sealedglass ampoule435 containing liquid monomer is inserted into thecontainment tube410. Thecap420 is placed on thetube410, sealing the containment tube closed.
• The[0102]cap420 is then tightened onto theampoule435, desirably forcing theampoule435 against the breakingelement415 and fracturing theampoule435. Liquid monomer will desirably flow into the containment tube, through thesupply lumen425 and into contact with the powdered component within thereceptacle12. Thevent lumen425 will desirably relieve any vacuum which could be formed in the containment tube.
• The liquid and powdered components are now mixed in the manner previously described. Once mixing is completed, a[0103]plunger460 can be inserted through openings (not shown) in theactuator18 andstationary seal448 whereby the slidingseal450 can be advanced towards the mixture within thereceptacle12. If desired, the slidingseal450 can incorporate a labyrinth seal or other arrangement which permits air to flow past the sliding seal. Desirably, any air and/or vaporized monomer which flows past the slidingseal450 will be contained by thestationary seal448. Once in contact with the PMMA mixture, the slidingseal450 will desirably pressurize the mixture, which can then be dispenses in the previously described manner.
• With this embodiment, the PMMA mixture can be dispensed from the mixing and dispensing system without significant release of monomer fumes. Once dispensing is complete, the entire closed system may be disposed of safely.[0104]
• FIGS. 24A, 24B,[0105]25 and26 depict various embodiments of mixing elements useful in conjunction with the previously-described closed mixing and transfer system. These mixing elements are particularly well suited to collapse and/or folding after mixing has been completed to facilitate advancement of the slidingseal450 and dispensing of the PMMA mixture. More specifically, FIGS. 24A and 24B depict views of a mixingelement16 comprising a series ofsections460 which mix the PMMA components in response to rotation of the mixing element but, when compressed, desirably fold in an accordion-like fashion to allow advancement of the slidingseal450 and dispensing of the PMMA mixture. FIG. 25 depicts a mixingelement16 comprising a helical section which mixes the PMMA components in response to rotation of the mixingelement16 but, when compressed, desirably compresses in a spring-like fashion to permit advancement of the slidingseal450 and dispensing of the PMMA mixture. FIG. 26 depicts a mixingelement16 comprising a plurality of helical sections which operate in a similar fashion.
• The features of the invention are set forth in the following claims.[0106]

Claims (15)

What is claimed is:

1. A device for mixing a bone filling material comprising:

a receptacle for receiving components of the bone filling material in an unmixed condition;

a mixing element insertable into the receptacle to mix the components;

an actuator for the mixing element including a drive member and a driven member coupled to the drive member and removably coupled to the mixing element.

2. A device as inclaim 1, wherein the mixing element comprises a paddle that mixes the components in response to rotation.

3. A device as inclaim 2, wherein the drive member rotates the paddle.

4. A device as inclaim 1, wherein the mixing element includes structure to promote mixing of the components.

5. A device as inclaim 4, wherein the structure comprises a plurality of apertures.

6. A device as inclaim 1, further comprising:

a plunger insertable into the receptacle after removal of the mixing element to dispense filling material from the receptacle.

7. A device as inclaim 1, further comprising a stand to hold the receptacle.

8. A device as inclaim 1, further comprising a dispenser attachable to the receptacle to dispense the filling material.

9. A device as inclaim 8, wherein the dispenser comprises a nozzle.

10. A device as inclaim 8, the dispenser comprising a fitting incorporated in a distal tip of the receptacle.

11. A device as inclaim 8, the dispenser comprising a tube incorporated in a distal tip of the receptacle.

12. A device as inclaim 1, wherein the actuator includes a drive train that couples a drive member to a driven member.

13. A device as inclaim 12, the drive train comprising a planetary gear system.

14. A device as inclaim 1, wherein the actuator includes linkage imparting rotation of the drive member to the driven member.

15. A device as inclaim 1, wherein the drive member is operable manually.

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