U.S. patent application number 09/980648 was filed with the patent office on 2002-12-19 for systems and methods for mixing and transferring flowable materials.
This patent application is currently assigned to Kyphon Inc.. Invention is credited to Sand, Paul M..
Application Number | 20020191487 09/980648 |
Document ID | / |
Family ID | 22917719 |
Filed Date | 2002-12-19 |
United States Patent
Application |
20020191487 |
Kind Code |
A1 |
Sand, Paul M. |
December 19, 2002 |
Systems and methods for mixing and transferring flowable
materials
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.
Inventors: |
Sand, Paul M.; (San Carlos,
CA) |
Correspondence
Address: |
RYAN KROMHOLZ & MANION, S.C.
Post Office Box 26618
Milwaukee
WI
53226-0618
US
|
Assignee: |
Kyphon Inc.
|
Family ID: |
22917719 |
Appl. No.: |
09/980648 |
Filed: |
October 25, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60243195 |
Oct 25, 2000 |
|
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|
Current U.S.
Class: |
366/252 |
Current CPC
Class: |
A61F 2002/3009 20130101;
B01F 35/562 20220101; A61B 2017/00902 20130101; A61B 2050/0066
20160201; A61F 2250/0071 20130101; A61B 2050/0083 20160201; A61F
2250/0091 20130101; B01F 2101/20 20220101; A61B 17/8827 20130101;
A61B 50/33 20160201; B01F 33/5011 20220101; B01F 27/054 20220101;
B01F 27/11451 20220101 |
Class at
Publication: |
366/252 |
International
Class: |
B01F 007/20 |
Claims
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 in claim 1, wherein the mixing element comprises a
paddle that mixes the components in response to rotation.
3. A device as in claim 2, wherein the drive member rotates the
paddle.
4. A device as in claim 1, wherein the mixing element includes
structure to promote mixing of the components.
5. A device as in claim 4, wherein the structure comprises a
plurality of apertures.
6. A device as in claim 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 in claim 1, further comprising a stand to hold the
receptacle.
8. A device as in claim 1, further comprising a dispenser
attachable to the receptacle to dispense the filling material.
9. A device as in claim 8, wherein the dispenser comprises a
nozzle.
10. A device as in claim 8, the dispenser comprising a fitting
incorporated in a distal tip of the receptacle.
11. A device as in claim 8, the dispenser comprising a tube
incorporated in a distal tip of the receptacle.
12. A device as in claim 1, wherein the actuator includes a drive
train that couples a drive member to a driven member.
13. A device as in claim 12, the drive train comprising a planetary
gear system.
14. A device as in claim 1, wherein the actuator includes linkage
imparting rotation of the drive member to the driven member.
15. A device as in claim 1, wherein the drive member is operable
manually.
Description
RELATED APPLICATION
[0001] This application claims the benefit of United States
provisional application Serial No. 60/243,195 filed Oct. 25,
2001.
FIELD OF THE INVENTION
[0002] 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.
BACKGROUND OF THE INVENTION
[0003] 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.
[0004] 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.
[0005] 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.
SUMMARY OF THE INVENTION
[0006] 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.
[0007] 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.
[0008] 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).
[0009] 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.
[0010] 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.
[0011] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] 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;
[0013] 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;
[0014] FIG. 3 is a perspective view of a stand that forms a part of
the system shown in FIG. 1A;
[0015] FIG. 4 is perspective side view of an actuator that can form
a part of the systems shown in FIGS. 1A and 1B;
[0016] FIGS. 4A-4F are perspective side views of alternate
embodiments of actuator handle designs;
[0017] FIG. 5A is a bottom view of the actuator shown in FIG.
4;
[0018] FIG. 5B is a bottom view of an alternate embodiment of an
actuator;
[0019] FIG. 6A is an exploded, perspective view of the actuator
shown in FIG. 4;
[0020] FIG. 6B is an exploded, perspective view of an alternate
embodiment of an actuator;
[0021] 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;
[0022] 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;
[0023] 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;
[0024] 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;
[0025] 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;
[0026] FIG. 12 is an exploded view of the actuator, mixing element,
receptacle, and stand assembly, as also shown in assembled view in
FIG. 13;
[0027] 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;
[0028] FIG. 14 is a perspective view showing the plunger being
inserted into the receptacle after the materials have been mixed in
the receptacle;
[0029] FIG. 15 is a perspective view showing the stand being
removed from the receptacle prior to dispensing material from the
receptacle;
[0030] FIG. 16 is a perspective view of the plunger inserted into
the receptacle containing the material, which is now ready to be
dispensed;
[0031] FIG. 17 is a perspective view of the material mixed within
the receptacle being dispensed from the receptacle;
[0032] FIG. 18 is a bottom view of the upper half of the actuator
that forms part of the system shown in FIG. 1B;
[0033] FIG. 19 is a perspective view of the plunger assembly
showing an opening for an air purge valve;
[0034] FIG. 20 is a perspective view of one embodiment of a
dispenser valve with an assembly for securing to the receptacle of
FIG. 2B;
[0035] FIG. 21 is a perspective view of the receptacle of FIG. 2B
with an optional attached vacuum line; and
[0036] FIG. 22 is a partially cut-away view of the receptacle of
FIG. 21;
[0037] FIG. 23 is another partially cut-away view of the receptacle
of FIG. 21;
[0038] FIG. 24A is a perspective view of an embodiment of a
collapsible mixing element suited for use in the receptacle of FIG.
21;
[0039] FIG. 24B is a side view of the collapsible mixing element of
FIG. 24A;
[0040] FIG. 25 is a perspective view of another embodiment of a
collapsible mixing element suited for use in the receptacle of FIG.
21;
[0041] FIG. 26 is a perspective view of another embodiment of a
collapsible mixing element suited for use in the receptacle of FIG.
21.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0042] 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.
[0043] 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.
I. THE COMPONENT PARTS
[0044] FIG. 1A shows component parts, arranged as a kit 200, 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, the kit 200 includes a receptacle 12
for receiving materials for mixing and for, after mixing,
transferring or dispensing the materials a stand 14 for receiving
the receptable 12; a mixing element 16 that can be inserted into
the receptacle 12 to mix the materials; an actuator 18 to drive the
mixing element 16; a plunger 20 that can be inserted into the
receptacle 12 to urge mixed materials from the receptacle 12; a
dispensing element 22 to dispense the mixed materials urged from
the receptacle 12; and a measuring device 24 to measure materials
placed in the receptacle 12 for mixing.
[0045] Desirably, the components 12, 14, 16, 18, 20, 22 and 24
comprise a substantially rigid metal, plastic or ceramic material.
In one embodiment, the components 12, 14, 16, 20, 22 and 24
comprise polypropylene, and component 18 comprises Acetal
homopolymer (DELRIN.RTM. 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.
[0046] A. The Receptacle
[0047] As shown in FIG. 2A, the receptacle 12 has a proximal end 30
and a distal end 32. The receptacle 12 further has an interior bore
37 which desirably extends from the proximal end 30 to the distal
end 32. The distal end 32 carries a distal tip 34, through which
one may dispense a material such as a bone filling material.
[0048] The receptacle 12 is sized to separately accommodate the
mixing element 16 and the plunger 20 at different stages of use.
The interior surface of the distal tip 34 is sized to support the
distal tip 62 of the mixing element 16 during use, as will be
described in greater detail later. The proximal end 30 carries a
set of tabs 36 on an outer surface 33 of the receptacle 12, to
couple the receptacle to the actuator 18, which, in turn,
releasably couples to the proximal end 56 of the mixing element 16.
When the plunger 20 is inserted into the receptacle 12, the tabs 36
also allow the physician to grasp and operate the receptacle 12 and
plunger 20 like a syringe, for dispensing materials after mixing,
as will be described later.
[0049] In one embodiment, the receptacle 12 has a volume of
approximately seventy cubic centimeters (70 cc). Of course, other
size receptacles 12 could be used, depending upon the size of the
mixing element 16 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. The
outer surface 33 of the receptacle 12 desirably includes a
graduated scale 39 showing the volume inside the receptacle 12.
Preferably, the graduated scale 39 begins near the distal tip 34 of
the receptacle 12. The receptacle 12 is desirably made of
transparent polypropylene to allow viewing of the materials to be
mixed when placed in the receptacle 12, during mixing and during
transfer.
[0050] In an alternate embodiment, as shown in FIG. 2B, the
receptacle 12 at the distal end 32 comprises a receptacle base 35.
The receptacle base 35 is generally hemispherical in shape and
supports the interior bore 37 of the receptacle 12. Within the
interior bore 37 of the receptacle 12, at the receptacle base 35,
is located a central neck (not shown) that is sized to accept and
to securely hold the distal tip 62 of the mixing element 16, as
previously described in connection with the previous embodiment.
The receptacle base 35 desirably stabilizes and elevates the
interior bore 37 and allows for easier dispensing or transfer of
the mixed material. The receptacle base 35 is sized to provide a
solid footing to minimize tipping of the receptacle 12. The
receptacle 12 has an outlet 34B for dispensing the mixed bone
filling material.
[0051] If desired, the receptacle 12 may incorporate a vacuum
attachment 31 (see FIG. 2B) for a standard operating room suite
vacuum hose, to evacuate fumes in the receptacle 12 and/or degas
the material. The vacuum hose may be further secured by an indent
31A in the receptacle base 35. If further desired, the receptacle
12 may form a cartridge for a bone filling material delivery
gun.
[0052] B. The Stand
[0053] In the system shown in FIG. 1A, the stand 14 (see FIG. 3)
supports the receptacle 12 during mixing. The stand 14 has an upper
side 40 and a lower side 42. The upper side 40 has a central neck
44 that is sized to accept and to securely hold the distal end 32
of the receptacle 12. Centered within the neck 44 is a small
chamber 46 that is sized to accept the distal tip 34 of the
receptacle 12. The lower side 42 of the stand 14 has a flat surface
which allows the stand 14 to sit evenly on a surface such as a
treatment table.
[0054] A separate stand 14 is not absolutely necessary for the
system shown in FIG. 1B as the receptacle base 35 is incorporated
directly into the receptacle 12.
[0055] C. The Mixing Element
[0056] The mixing element 16 can be variously configured, and FIGS.
7, 8 and 9 show different representative configurations. In use,
the mixing element 16 rotates within the receptacle 12 to mix the
materials contained in the receptacle.
[0057] In the various described configurations, the mixing element
16 has an upper side 50 and a lower side 52. In these embodiments,
the upper and lower sides 50 and 52 can have an outwardly extending
central rib 51 that acts as a stiffener to maintain integrity of
the mixing element 16. The mixing element 16 may also include one
or more crosswise ribs 53.
[0058] The mixing element 16 has a proximal end 56 and a distal end
57. The distal end 57 desirably carries a flat tip 62 that is
adapted to fit into the distal tip 34 of the receptacle 12. The
distal tip 62 of the mixing element 16 desirably mixes the
components located in the distal tip 34 of the receptacle 12. The
distal tip 62 also desirably acts as a bearing surface within the
distal tip 34 of the receptacle 12, to keep the mixing element 16
centered within the receptacle 12 as it rotates, as well as
constraining side-to-side movement of the mixing element 16 within
the receptacle 12. The distal tip 62 also acts to maintain secure
engagement of the mixing element 16 to the actuator 18
[0059] If desired, the proximal end 56 can carry a solid
cylindrical tip 58, although the proximal end 56 could be various
configurations suitable for attachment to the actuator 18. The tip
58 is adapted to couple to the actuator 18, as will be described in
greater detail later. The tip 58 has a crosspiece 60 that
facilitates the transmission of rotational forces from the actuator
18 to the mixing element 16 as shown in FIGS. 7, 8 and 9. The
crosspiece 60 also acts to firmly engage the mixing element 16 with
the keyway 89 of the actuator 18 by snapping in place. The tip 58
may also contain ridges 59 as shown in FIG. 9 to impart further
strength and stability.
[0060] The mixing element 16 also desirably has one or more
apertures 61, 63, 65, 67, 68, and 69, as shown in FIGS. 7-9. The
apertures 61, 63, 65, 67, 68, and 69 function to assist in mixing
the chosen components, such as a powdered material and a liquid
monomer, together. The apertures 61, 63, 65, 67, 68, and 69 are
desirably large enough to allow some of the mixture to flow through
the mixing element 16, thereby allowing the mixing element 16 to
rotate within the receptacle 12 with a minimum of resistance and
maximizing the mixing of the chosen mixing materials. If the sizes
of the apertures 61, 63, 65, 67, 68, and 69 are increased, less
resistance to rotation is noted. However, there is a concomitant
need for additional rotation of the mixing element 16 in the
mixture to ensure thorough mixing. Larger apertures ease the mixing
process, while smaller apertures may result in the components
"riding up" the mixing element 16. In such a case, the mixing must
be stopped momentarily in order to allow the components to fall
back into the mixture.
[0061] Desirably, the mixing element 16 is sized to extend
substantially across the interior of the receptacle 12. Such an
arrangement can facilitate mixing of the powder and liquid
components, because rotation of the mixing element 16 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 the receptacle 12 and
the mixing element 16 are not absolutely necessary, in least one
embodiment the mixing element 16 and the side walls of the
receptacle 12 are in very close proximity.
[0062] In the embodiment shown in FIG. 8, the mixing element 16
desirably has a series of small, evenly spaced apertures 65
beginning near the proximal end 56 of the mixing element 16,
followed by at least two large apertures 69 extending toward the
distal end 57 of the mixing element 16, and at least two
intermediate sized apertures 67 at the distal end 57. 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 the actuator 18. In this
embodiment approximately five to twenty rotations of the actuator
18 should be sufficient to ensure a proper mixture in the case of a
bone filling material.
[0063] In the embodiment shown in FIG. 7, the mixing element 16 has
a plurality of evenly spaced apertures 61 that are positioned
parallel to the rib 51, and the mixing element 16 further has at
least two apertures 63 at the distal tip 62. This embodiment
requires approximately five to ten rotations of the actuator 18 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.
[0064] In the embodiment shown in FIG. 9, the mixing element 16 has
two larger apertures 68 beginning near the proximal end 58 of the
mixing element 16, followed by at least two large apertures 69
extending toward the distal end 57. This embodiment requires
approximately fifteen to twenty rotations of the actuator 18 to
properly mix the bone filling material. The minimal surface area of
the mixing element 16 as shown in FIG. 9 allows only a small amount
of bone filler material to be retained on the mixing element 16
when it is removed from the receptacle 12 after thorough
mixing.
[0065] In other alternative embodiments, the mixing element 16
could incorporate any number of apertures of various sizes and
shapes (not shown).
[0066] D. The Actuator
[0067] The actuator 18 (see FIGS. 4 and 5A and 5B) drives the
mixing element 16. Desirably, the actuator 18 is formed from
DELRIN.RTM. material or a clear or colored nylon. As shown in FIG.
4, the actuator 18 is in a palm-sized, cylindrical shape.
[0068] The actuator 18 has an outer surface 70 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. The actuator 18 has an upper half 72 and a lower half 74
(see also FIGS. 6A and 6B) that are adapted to be connected
together in various ways, including fasteners, adhesives, or a
snap-fit.
[0069] The upper half 72 of the actuator 18 functions as a drive
member, while the lower half 74 of the actuator 18 is a driven
member. The upper half 72 rotates relative to the lower half
74.
[0070] Both the upper half 72 and the lower half 74 of the actuator
18 have an interior side 76 and an exterior side 78. As shown in
FIG. 6A, the interior side 76 of the upper half 72 contains a ring
gear 73. The interior side 76 of the lower half 74 contains a
planetary gear arrangement 84 that meshes with the ring gear
73.
[0071] The planetary gear arrangement 84 includes a sun gear 86 and
one or more planet gears 88. The sun gear 86 is fixed axially to
the lower half 74 of the actuator 18 by means of a screw 95. The
planet gears 88 are fixed to a retainer ring 92 by screws 94. In
one alternative embodiment, the planet gears 88 would comprise two
gears, each gear positioned on opposite sides of the sun gear
86.
[0072] The teeth of the planet gears 88 mesh with the teeth of the
ring gear 73. The teeth of the planet gears 88 also mesh with the
sun gear 86. Rotation of the upper half 72 of the actuator 18
relative to the lower half 74 of the actuator 18 rotates the ring
gear 73. This, in turn, imparts rotation to the planet gears 88
within the stationary lower half 74 of the actuator 18. Rotation of
the planet gears 88, in turn, rotates the sun gear 86 within the
lower half 74 of the actuator 18. In the embodiment where there are
three planet gears 88, a single rotation of the ring gear 73 (i.e.,
the upper half 72 of the actuator 18) equals approximately four
rotations of the sun gear 86 within the lower half 74 of the
actuator 18. In the embodiment where there are two planet gears 88,
a single rotation of the ring gear 73 equals approximately three
rotations of the sun gear 86.
[0073] As shown in FIG. 5A, the exterior side 78 of the lower half
74 of the actuator 18 has a central slot 96 which receives the
cylindrical tip 58 of the mixing element 16. An axle 87 projecting
from the sun gear 86 (see FIG. 6A) extends into the slot 96. The
crosspiece 60 on the tip 58 fits into a keyway 89 on the axle 87
(see FIG. 5A), which couples the mixing element 16 to the sun gear
86. Thus, rotation of the sun gear 86 imparts rotation to the
mixing element 16.
[0074] Additionally, the exterior side 78 of the lower half 74 has
stabilizing structure 98 (see FIG. 5A). The structure 98 abuts
against and/or grips the tabs 36 of the receptacle 12 to prevent
the receptacle 12 from rotating while rotation is imparted by the
sun gear 86 to the mixing element 16. The stabilizing structure 98
is secured to the lower half 74 of the exterior side 78 by
fasteners 99. If desired, the actuator 18 may incorporate an
attachment for a standard operating room suite vacuum hose (not
shown), to evacuate fumes within the receptacle 12.
[0075] In an alternate embodiment (see FIG. 6B), the upper half 72
of the actuator 18 has an integral ring gear 73 adapted into the
interior surface 71 (see FIG. 18) of the actuator 18. The lower
half 74 of the actuator 18 has a planetary gear arrangement 84 that
meshes with the ring gear 73. The planetary gear arrangement 84
includes a sun gear 86 and a plurality of planet gears 88.
Desirably, the planetary gear arrangement 88 comprises two planet
gears 88. The sun gear 86 is fixed axially to the lower half 74 of
the actuator 18 by means of an axle 87. The axle 87 is adapted at
the top to snap-fit with the upper half 72 and is adapted at the
bottom to receive the tip 58 of the mixing element 16. The middle
section of the axle 87 is squared off to hold the sun gear 86 in
place and to receive rotational forces imparted by the sun gear
86.
[0076] The planet gears 88 are fixed to the lower half 74 of the
actuator 18 by hollow gear posts 93. The retainer ring 92 has
retention tabs 90 which fit through the central bore of the planet
gears 88 and extend into the hollow gear posts 93 (see FIG. 6B) .
The retention tabs 90 have small tangs extending downward through
the hollow gear posts 93 to securely engage the retainer ring 92 to
the lower half 74 of the actuator 18. The retainer ring 92 also
desirably has stabilizer feet 97 extending downward to provide
strength and stabilization to the planetary gear arrangement
84.
[0077] As shown in FIG. 5B, the exterior side 78 of the lower half
74 of the actuator 18 has a stabilizing structure 98B which is
generally oblong to accommodate insertion of the receptacle 12. The
oblong shape of the stabilizing structure 98B prevents the
receptacle 12 from rotating while rotation is imparted by the sun
gear 86 to the axle 87 which couples to the mixing element 16.
[0078] E. The Plunger
[0079] The plunger 20 (see FIGS. 14 and 16) fits into the bore 37
of the receptacle 12. Advancement of the plunger 20 within the
receptacle 12 desirably expels air from the receptacle 12, as well
as dispenses material from the receptacle 12.
[0080] As shown in FIG. 19 the plunger 20 may also desirably
contain one or more openings 103 for a valve that automatically
purges the air in the receptacle 12 between the plunger 20 and
mixed bone filling material. The plunger 20 can contain a seal 101
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, the plunger 20 can
contain a valve with a small ball bearing (not shown) which allows
air to escape as the plunger 20 is advanced through the receptacle
12. The ball bearing (not shown) may be made from a plastic
material that is less dense than the bone filling material. As the
plunger 20 contacts the viscous bone filling material, the ball
bearing is forced up into a closed position. Purging the air allows
for direct contact between the plunger 20 and material, which
provides for improved dispensing control of the material.
[0081] F. The Dispensing Element
[0082] In the system shown in FIG. 1A, the dispensing element 22
comprises a nozzle 100 that is adapted to fit on the distal tip 34
of the receptacle 12 (see FIG. 17). In another embodiment, a
LUER.RTM. fitting (not shown) is incorporated into the distal tip
34 of the receptacle 12. In another embodiment, a fitting (not
shown) is incorporated into the distal tip 34 of the receptacle 12,
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 the distal tip 34 of the receptacle 12, the tubing being
adapted to fit within a 5 cc or 10 cc syringe body.
[0083] In the system shown in FIG. 1B, the dispensing element 22
desirably snap fits onto the distal end 32 of the receptacle 12 by
means of clips 121 (see FIG. 20). The dispensing element 22 may
also be attached to the receptacle 12 by other means, such as with
adhesive, welding or by other means known in the art. The
dispensing element 22 desirably mates with the outlet 34B of the
receptacle 12 (see FIG. 2B) . A stopcock valve (not shown), or
other type of suitably valve, can be located inside the valve body
125 and have a outlet 127 for the mixed material. The dispensing
element 22 can have one or more dispensing handles 123 located at
the end(s) of the valve body 125. Two dispensing handles 123, as
shown in FIG. 20, can allow for either right- or left-handed
operation of the dispensing element 22. A LUER.RTM. fitting 129 is
desirably incorporated onto the valve body 125, 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 the valve body 125, depending upon the type of
instrument receiving the transferred mixed material.
[0084] G. The Measuring Device
[0085] The measuring device 24 (see FIG. 1A) is used to measure
components before placing the components into the receptacle for
mixing. The measuring device 24 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.
[0086] H. The Funnel
[0087] The funnel 10 is used to facilitate placing or pouring of
the components to be mixed into the receptacle 12 (see FIG.
1B).
II. ILLUSTRATIVE USE OF THE SYSTEM
[0088] In the embodiment shown in FIG. 1A, the receptacle 12, stand
14, mixing element 16, actuator 18, plunger 20, dispenser 22 and
the measuring device 24, as well as the components to be mixed, are
gathered together for use, or are withdrawn as needed from the kit
200. The physician or an assistant inserts the distal end 32 of the
receptacle 12 into the neck 44 of the upper side 40 of the stand 14
(see FIG. 10). Desirably, the distal tip 34 of the receptacle 12 is
held within the small chamber 46 located on the upper side 40 of
the stand 14, desirably sealing the distal tip 34 closed.
[0089] As FIG. 20 shows, the physician may use the measuring device
24 to measure a component to be mixed, such as a powdered component
for poly(methyl methacrylate) bone cement. The powdered component
is poured into the receptacle 12. If the receptacle 12 bears a
graduated scale 39 on its outer surface 33, the component can be
added to the receptacle 12 until the desired level is reached.
After the powdered component is added to the receptacle 12, another
component, such as a liquid monomer for bone cement, is added.
[0090] The mixing element 16 and actuator 18 are then obtained.
Desirably, the proximal end 56 of the mixing element 16 has been
inserted into the slot 96 located on the exterior side 78 of the
lower half 74 of the actuator 18 (as FIG. 11 shows). The assembly
is now inverted and the distal end 57 of the mixing element 16
inserted into the proximal end 30 of the receptacle 12 (shown in
exploded view in FIG. 12). Desirably, the mixing element 16 is
inserted such that the distal tip 62 of the mixing element 16
extends into the distal tip 34 of the receptacle 12. The actuator
18 desirably engages with the tabs 36 located on the proximal end
30 of the receptacle 12, so that the lower half 74 of the actuator
18 remains stationary relative to the receptacle 12.
[0091] The physician now grasps the upper half 72 of the actuator
18 with one hand, while holding the stand 14, the receptacle 12 or
the stand 14 and receptacle 12, with the other hand (see FIG. 13).
The upper half 72 of the actuator 18 is then rotated back and
forth, first clockwise and then counterclockwise, e.g. (or vice
versa), by half-turns, relative to the receptacle 12.
Alternatively, or in conjunction with this back and forth motion, ,
the actuator 18 may be rotated in a single direction. Desirably,
the actuator 18 is rotated enough times to adequately mix the
mixture.
[0092] After the mixture is adequately mixed, the actuator 18 and
mixing element 16 are removed from the receptacle 12 and set aside.
If desired, the mixing element 16 may be scraped against the top of
the receptacle 12 to remove mixture clinging to the element 16,
desirably returning such mixture to the receptacle 12. Next, the
plunger 20 is inserted into the proximal end 30 of the receptacle
12 (see FIG. 14). The assembly can now be safely inverted and the
stand 14 removed from receptacle 12 (see FIG. 15). Desirably, the
stand 14 will not be removed from the receptacle 12 before the step
of inserting the plunger 20 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 the distal tip 34 of the
receptacle 12.
[0093] After the stand 14 is removed from the receptacle 12, air
can be expelled from the distal tip 34 of the receptacle 12 by
advancing the plunger 20 in the usual fashion of purging air from a
syringe. The mixture may be dispensed directly from the receptacle
12 by advancing the plunger 20. If desired, a dispenser 22 is
fitted onto the distal tip 34 of the receptacle 12. In one
embodiment, if the dispenser 22 is a nozzle 100, the mixture is
dispensed through the nozzle 100. In another embodiment, if the
distal tip 34 of the receptacle 12 incorporates a LUER.RTM.
fitting, the LUER.RTM. 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.RTM. fitting is incorporated
into the distal tip 34 of the receptacle 12, the combination allows
for the direct filling of multiple bone filler devices. In another
embodiment, if the distal tip 34 of the receptacle 12 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 the
receptacle 12. In another embodiment, the distal tip 34 of the
receptacle 12 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.
[0094] The system shown in FIG. 1B contains additional features
with enhanced ease of use and fewer steps. The receptacle 20 is
packaged in the kit 200 with the dispensing element 22 in the
closed position. After gathering the system parts (receptacle 12,
mixing element 16, actuator 18, plunger 20 and funnel 10) from the
sealed kit 200 as well as the material to be mixed, the physician
or an assistant positions the funnel 10 within the proximal end 30
of the receptacle 12 and pours the powdered component into the
receptacle 12. If desired, additional powdered materials, such as
sterile barium sulfate (to make the mixture radiopaque) or
antibiotics (to prevent infection) may be added to the receptacle
12 before addition of the liquid monomer. The mixing element 16 and
actuator 18 are coupled together as previously described and
inserted into the receptacle 12. The actuator 18 is positioned to
engage with the tabs 36 on the proximal end 30 of the receptacle
12. The physician or an assistant now rotates the actuator 18 to
mix the material as previously described. The monomer fumes in the
receptacle 12 may be desirably evacuated from the receptacle 12 by
the vacuum hose attachment 31. After the mixture is adequately
mixed, the actuator 18 and mixing element 16 are removed from the
receptacle 12 and set aside. Next, the plunger 20 is inserted into
the proximal end 30 of the receptacle 12. Air can be automatically
purged from the system through the openings 103 in the plunger 20.
The residual air/monomer mixture may then be evacuated from the
interior bore 37 of the receptacle 12 by the vacuum hose attachment
31, 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 dispensing element 22 by pushing down
on the plunger 20. Alternatively, the flow of the mixture may be
controlled by rotating the dispensing handles 123 to open and close
the stopcock valve (not shown).
[0095] 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 16 (having bone filler material thereon) may be removed
from the actuator 18 and replaced with a new mixing element 16,
allowing the actuator 18 to be used to mix an additional batch of
bone filler material. In such a case, the kit 200 could contain a
single actuator 18 and measuring device 24, with multiple
receptacles 12, stands 14, mixing elements 16, plungers 20 and
dispensing elements 22 to allow mixing of multiple batches of bone
filler material.
III. CLOSED CEMENT MIXING AND TRANSFER SYSTEM
[0096] 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.
[0097] 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.RTM. 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.
[0098] 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.
[0099] 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 receptacle 12 incorporates a monomer dispensing
body 400. The monomer dispensing body 400 comprises a retaining
clip 405, a containment tube 410, a breaking element 415, a cap
420, a supply lumen 425 and a vent lumen 430. Desirably, the
dispensing body is secured to the receptacle 12, with the supply
lumen 425 and vent lumen 430 communicating with the interior of the
receptacle 12 through one or more openings (not shown) in the
receptacle wall. The dispensing body 400 may be secured to the
receptacle in various ways, including clips, adhesive, welding or
by other methods known in the art.
[0100] As shown in FIG. 23, a stationary seal 448 desirably engages
the upper opening of the receptacle 12 in an air-tight fashion,
desirably sealing the receptacle 12 from the operating room
environment. A sliding seal 450 is desirably positioned below the
stationary seal 448 and within the receptacle 12. These seals 448
and 450 can comprise various known sealing materials, including
latex rubber. Desirably, the seals 448 will permit rotation of the
mixing element 16 and axle 87 while maintaining a substantially
air-tight seal between the receptacle contents and the atmosphere.
In addition, the sliding seal 450 can desirably be moved
longitudinally within the receptacle 12. If desired, the sliding
seal can incorporate an internal slot or opening (not shown), which
permits the sliding seal 450 to slide along the central axis of the
mixing element 16 while maintaining a substantially air-tight seal
with the mixing element 16.
[0101] To prepare the bone cement mixture, a measured amount of
powdered PMMA component is introduced into the receptacle 12. The
mixing element and actuator are then attached to the receptacle,
with the seals 448 and 450 sealingly engaging the receptacle 12. A
sealed glass ampoule 435 containing liquid monomer is inserted into
the containment tube 410. The cap 420 is placed on the tube 410,
sealing the containment tube closed.
[0102] The cap 420 is then tightened onto the ampoule 435,
desirably forcing the ampoule 435 against the breaking element 415
and fracturing the ampoule 435. Liquid monomer will desirably flow
into the containment tube, through the supply lumen 425 and into
contact with the powdered component within the receptacle 12. The
vent lumen 425 will desirably relieve any vacuum which could be
formed in the containment tube.
[0103] The liquid and powdered components are now mixed in the
manner previously described. Once mixing is completed, a plunger
460 can be inserted through openings (not shown) in the actuator 18
and stationary seal 448 whereby the sliding seal 450 can be
advanced towards the mixture within the receptacle 12. If desired,
the sliding seal 450 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
sliding seal 450 will be contained by the stationary seal 448. Once
in contact with the PMMA mixture, the sliding seal 450 will
desirably pressurize the mixture, which can then be dispenses in
the previously described manner.
[0104] 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.
[0105] FIGS. 24A, 24B, 25 and 26 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 sliding seal
450 and dispensing of the PMMA mixture. More specifically, FIGS.
24A and 24B depict views of a mixing element 16 comprising a series
of sections 460 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 sliding
seal 450 and dispensing of the PMMA mixture. FIG. 25 depicts a
mixing element 16 comprising a helical section which mixes the PMMA
components in response to rotation of the mixing element 16 but,
when compressed, desirably compresses in a spring-like fashion to
permit advancement of the sliding seal 450 and dispensing of the
PMMA mixture. FIG. 26 depicts a mixing element 16 comprising a
plurality of helical sections which operate in a similar
fashion.
[0106] The features of the invention are set forth in the following
claims.
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