U.S. patent application number 10/365141 was filed with the patent office on 2003-08-21 for system and method for mixing bone cement.
Invention is credited to Chan, Kwan-Ho.
Application Number | 20030155381 10/365141 |
Document ID | / |
Family ID | 24418586 |
Filed Date | 2003-08-21 |
United States Patent
Application |
20030155381 |
Kind Code |
A1 |
Chan, Kwan-Ho |
August 21, 2003 |
System and method for mixing bone cement
Abstract
An apparatus for mixing bone cement in a vacuum includes a
container for mixing first and second components of a bone cement
in a vacuum, the container having a sealed body defining an
interior space and a selected quantity of the first component
disposed in the interior space. The container is provided with an
injection port for admitting the second component into the interior
space vacuum source. A mixing paddle is disposed in the interior
space and connected to a handle therefor extending out of the
container. A plurality of indirect pathways extend between the
interior space and the exhaust port which permit gas to pass
therethrough out of the interior space, but prevent the bone cement
first and second components from passing therethrough.
Inventors: |
Chan, Kwan-Ho; (Lubbock,
TX) |
Correspondence
Address: |
Mark J. Pandiscio
Pandiscio & Pandiscio
470 Totten Pond Road
Waltham
MA
02451
US
|
Family ID: |
24418586 |
Appl. No.: |
10/365141 |
Filed: |
February 11, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10365141 |
Feb 11, 2003 |
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09928674 |
Aug 13, 2001 |
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6516977 |
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09928674 |
Aug 13, 2001 |
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09115089 |
Jul 14, 1998 |
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09115089 |
Jul 14, 1998 |
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08604194 |
Feb 21, 1996 |
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5779356 |
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Current U.S.
Class: |
222/394 |
Current CPC
Class: |
B01F 35/713 20220101;
B01F 35/718 20220101; B01F 33/5011 20220101; B01F 2101/20 20220101;
B01F 31/441 20220101; B01F 35/181 20220101; A61B 2050/0066
20160201; B01F 33/70 20220101; B01F 35/187 20220101; B01F 23/565
20220101; B01F 35/75 20220101; A61F 2002/4685 20130101; B01F
35/7131 20220101; A61F 2002/30561 20130101; A61F 2250/0071
20130101; A61B 17/8827 20130101 |
Class at
Publication: |
222/394 |
International
Class: |
B65D 083/00 |
Claims
What is claimed is:
1. Apparatus for mixing bone cement in a vacuum, said apparatus
comprising: a container for mixing first and second components of a
bone cement in a vacuum, said container comprising: a sealed body
defining an interior space; a selected quantity of said bone cement
first component disposed in said interior space of said sealed
body; an injection port formed in said sealed body and
communicating with said interior space, said injection port being
adapted for interconnection with a holder containing a selected
quantity of the bone cement second component, whereby the second
component can be introduced into said interior space of said sealed
body; an exhaust port formed in said sealed body and communicating
with said interior space, said exhaust port being adapted for
interconnection with a vacuum source whereby a vacuum can be pulled
inside said interior space of said sealed body; an agitator
comprising a mixing paddle disposed in said interior space of said
sealed body and an actuating handle therefor disposed outside said
sealed body; and a plurality of indirect pathways extending between
said interior space of said sealed body and said exhaust port, said
plurality of indirect pathways being adapted to permit gas to pass
out of said interior space of said sealed body via said exhaust
port but to prevent said bone first component and the bone cement
second component from passing out of said interior space of said
sealed body via said exhaust port.
2. Apparatus according to claim 1 wherein said plurality of
indirect pathways are formed at least in part by barrier means
disposed between said interior space of said sealed body and said
exhaust port, said barrier means comprising an element formed out
of non-porous material, with said element having a plurality of
passageways extending through said element.
3. Apparatus according to claim 2 wherein said element is
positioned against an interior surface of said sealed body, and
further wherein said interior surface of said sealed body includes
a plurality of surface passageways formed therein, said passageways
in said barrier means and said surface passageways in said sealed
body together forming said indirect pathways.
4. Apparatus according to claim 1 wherein said container further
comprises an absorbent filter disposed in said exhaust port so that
said absorbent filter is located downstream from said indirect
pathways but upstream from any vacuum source interconnected with
said exhaust port, said absorbent filter being adapted to trap
non-gaseous materials exiting the interior of said sealed body via
said exhaust port.
5. Apparatus according to claim 1 wherein said container comprises
a sealed cartridge adapted for use in a cement dispenser.
6. Apparatus according to claim 1 wherein said container comprises
a sealed mixing bowl.
7. Apparatus according to claim 1 wherein said agitator comprises a
reciprocal agitator adapted to move said mixing paddle reciprocally
within said interior space of said sealed body when said actuating
handle is moved reciprocally outside said sealed body.
8. Apparatus according to claim 1 wherein said apparatus further
comprises: a vacuum line interconnecting said exhaust port with a
vacuum source; a check valve disposed in said vacuum line for
maintaining a vacuum pulled in the interior of said sealed body by
said vacuum source; a vacuum indicator disposed in said vacuum line
for indicating when a predetermined level of vacuum has been
attained in the interior of said sealed body; and a filter disposed
in said vacuum line for trapping selected materials passing through
said vacuum line.
9. Apparatus according to claim 8 wherein said filter is disposed
between said vacuum indicator and said check valve.
10. Apparatus for mixing bone cement in a vacuum, said apparatus
comprising: a container for mixing first and second components of a
bone cement in a vacuum, said apparatus comprising: a sealed body
defining an interior space; a selected quantity of said first bone
cement component disposed in said interior space of said sealed
body; an exhaust port formed in said sealed body and communicating
with said interior space, said exhaust port being adapted for
interconnection with a vacuum source whereby a vacuum can be pulled
inside said interior space of said sealed body; an agitator
comprising a mixing paddle disposed in said interior space of said
sealed body and an actuating handle disposed outside said sealed
body, with said mixing paddle being connected to said actuating
handle by a hollow shaft extending through said sealed body; said
hollow shaft comprising a thin-walled exterior tube and a resilient
interior tube, with said thin-walled exterior tube being connected
to said mixing paddle, and with said thin-walled exterior tube
being provided with a breakaway notch adjacent to where said
thin-walled exterior tube is connected to said mixing paddle, and
with a porous plug being disposed in the central passageway of said
resilient interior tube adjacent to where said shaft is connected
to said mixing paddle, said porous plug being connected to said
resilient interior tube and being adapted to permit gas and the
bone cement second component to pass through said porous plug but
to prevent said bone first component from passing through said
porous plug; and an injection port formed in said actuating handle
and communicating with the interior of said resilient interior
tube, said injection port being adapted for interconnection with a
holder containing a selected quantity of said bone cement second
component, whereby said bone cement second component can be
introduced into said interior space of said sealed body for mixing
with said bone cement first component.
11. Apparatus according to claim 10 wherein said sealed body
comprises a sealed cartridge adapted for use in a cement
dispenser.
12. An ampoule breaker/injector assembly for use in releasing a
fluid from an ampoule having a frangible neck, and for guiding the
fluid released from the ampoule into a sealed vessel, said assembly
comprising: a body having an interior space for receiving the neck
of the ampoule and at least a portion of a remainder of the
ampoule; injector means formed in said body and communicating with
said interior space, said injector means being adapted for
interconnection with the sealed vessel whereby when a vacuum is
drawn in the sealed vessel, the vacuum will be extended into said
interior space of said body; first means for causing said ampoule
to move longitudinally within said interior space when said ampoule
is disposed in said interior space and a vacuum is extended into
said interior space; and second means for causing said frangible
neck of said ampoule to break when said ampoule is moved
longitudinally within said interior space.
13. An ampoule breaker/injector assembly according to claim 12
wherein said second means comprise a wedge disposed in said
interior space.
14. An ampoule breaker/injector assembly according to claim 12
wherein said first means comprise an O-ring disposed in said
interior space.
15. An ampoule breaker/injector assembly according to claim 14
wherein said O-ring is in engagement with said ampoule.
16. An ampoule breaker/injector assembly according to claim 12
wherein said first means comprise a piston, said piston being
adapted to drive said ampoule longitudinally when a vacuum is
extended into said interior space.
17. Apparatus for mixing bone cement in a vacuum, said apparatus
comprising: a container for mixing first and second components of a
bone cement in a vacuum, said container comprising: a sealed body
defining an interior space; a selected quantity of said bone cement
first component disposed in said interior space of said sealed
body; an injection port formed in said sealed body and
communicating with said interior space, said injection port being
adapted for interconnection with a holder containing a selected
quantity of the bone cement second component, whereby the second
component can be introduced into said interior space of said sealed
body; an exhaust port formed in said sealed body and communicating
with said interior space, said exhaust port being adapted for
interconnection with a vacuum source whereby a vacuum can be pulled
inside said interior space of said sealed body; an agitator
comprising a mixing paddle disposed in said interior space of said
sealed body and an actuating handle therefor disposed outside said
sealed body; and an ampoule breaker/injector assembly for use in
releasing the bone cement second component from an ampoule having a
frangible neck, and for guiding the bone cement second component
released from the ampoule into said sealed body, said assembly
comprising: a housing having defined space for receiving the neck
of the ampoule and at least a portion of a remainder of the
ampoule; injector means formed in said housing and communicating
with said defined space, said injector means being adapted for
interconnection with said sealed body, whereby when a vacuum is
drawn in said sealed body, said vacuum will be extended into said
defined space of said housing; first means for causing the ampoule
to move longitudinally within said defined space when the ampoule
is disposed in said defined space and a vacuum is extended into
said defined space; and second means for causing the frangible neck
of the ampoule to break when the ampoule is moved longitudinally
within said defined space; whereby bone cement second component
released from the ampoule into said defined space in said housing
can be introduced into said interior space of said sealed body.
18. Apparatus according to claim 17 wherein said apparatus is
configured so that longitudinal motion of said actuating handle is
transferred to the ampoule.
19. Apparatus according to claim 18 wherein a portion of said
actuating handle engages a portion of the ampoule.
20. Apparatus according to claim 18 wherein said first means
comprise a piston disposed in said housing and engageable with a
portion of the ampoule, and a portion of said actuating handle
engages a portion of said piston.
21. Apparatus comprising: a substantially rigid vessel defining an
interior region; a frangible neck formed on said vessel and
communicating with said interior region of said vessel; a selected
quantity of a liquid bone cement disposed in said interior region
of said vessel; and a gas column disposed in said interior region
of said vessel.
22. A method for mixing first and second components of a bone
cement, said method comprising the steps of: providing a sealed
body defining an interior space and having therein a selected
quantity of said first component, and having therein an injection
port, an exhaust port, an agitator means disposed in said interior
space and connected to a handle disposed at least in part outside
of said interior space, and having indirect pathways extending
between said interior space and said exhaust port but prevent said
first and second components from passing out of said interior space
via said exhaust port; placing a holder having said second
component therein in communication with said injection port to
place said holder in communication with said interior space;
placing a vacuum source in communication with said exhaust port to
draw a vacuum in said interior space, to thereby draw said second
component into said interior space; and operating said handle to
move said agitator means in said interior space to mix said first
and second components while continuing said drawing of said vacuum
in said interior space, said pathways permitting passage of gas
therethrough from said interior space but preventing passages of
said first and second components therethrough.
23. A method for mixing first and second components of a bone
cement, said method comprising the steps of: providing a sealed
body defining an interior space and having therein a selected
quantity of said first component, and having therein an exhaust
port, an agitator means disposed in said interior space and
connected to a handle connected to said agitator means and
extending outside of said interior space, and having barrier means
in said interior space adjacent said exhaust port, said barrier
means being adapted to permit gas to pass therethrough and out of
said interior space via said exhaust port but prevent passage
therethrough of said first and second components, said handle
having an injection port therein outside of said interior space and
a channel extending through said handle to proximate said agitator
means; placing a vacuum source in communication with said exhaust
port to draw a vacuum in said interior space and said channel;
introducing said second component via said injection port and said
channel into said interior space; and operating said handle to move
said agitator means in said interior space to mix said first and
second components to form bone cement, while continuing said
drawing of said vacuum in said interior space, said barrier means
permitting passage of gas therethrough from said interior space but
preventing passage therethrough of said first and second
components.
24. Apparatus comprising: a substantially rigid vessel defining an
interior region; an egress port formed on said rigid vessel and
communicating with said interior region; a piston movably disposed
in said interior region of said vessel and making a close sliding
fit therewith so as to define a volume of variable size; and a
selected quantity of a liquid bone cement component disposed in
said volume.
25. Apparatus comprising: a substantially flexible vessel defining
an interior region; an egress port formed on said flexible vessel
and communicating with said interior region; and a selected
quantity of a liquid bone cement component disposed in said
interior region of said flexible vessel.
26. Apparatus comprising: a substantially rigid vessel defining an
interior region; a frangible neck formed on said vessel and
communicating with said interior region of said vessel; a selected
quantity of a liquid bone cement disposed in said interior region
of said vessel; a gas column disposed in said interior region of
said vessel; and an injector element for receiving the neck of said
vessel and at least a portion of the remainder of said vessel and
for making an airtight seal with said at least a portion of the
remainder of said vessel, said injector device including an egress
port.
Description
FIELD OF THE INVENTION
[0001] This invention relates to bone cements in general, and more
particularly to systems and methods for preparing bone cements from
a solid component and a liquid component by mixing the two
components in a vacuum.
BACKGROUND OF THE INVENTION
[0002] In many orthopaedic surgical procedures, bone cements are
used to fix implants to bone. These bone cements are generally
polymeric and/or copolymeric materials which are prepared by
polymerizing the cement's constituent components as the cement is
needed during the surgical procedure. More particularly, such bone
cements are typically prepared by polymerizing a liquid monomer and
a powdered polymer and/or copolymer, e.g. polymethyl methacrylate
("PMMA") and/or a polystyrene copolymer.
[0003] Unfortunately, it has been found that as the cement's
constituent components are mixed together to effect the
aforementioned polymerization, air bubbles are generally introduced
into the cement. The presence of these air bubbles increases the
porosity of the cement and thereby undermines its structural
integrity. Conversely, it has also been found that the strength of
the cement can be significantly increased if the air bubbles are
eliminated from the mixture.
[0004] On account of the foregoing, bone cements of the sort
described above are preferably prepared by mixing the constituent
components in a vacuum.
[0005] Unfortunately, prior art systems and methods for mixing bone
cement in a vacuum in an operating room environment have not proven
to be particularly convenient to use. Among other things, such
prior art systems and methods generally require operating room
personnel to transfer the bone cement's powdered polymer and/or
copolymer component into a mixing bowl from its shipping container,
and then to transfer the bone cement's liquid monomer component
from its shipping container into the same mixing container prior to
establishing a vacuum in the mixing bowl and then effecting
mixing.
OBJECTS OF THE INVENTION
[0006] Accordingly, one object of the present invention is to
provide an improved system for mixing bone cement.
[0007] And another object of the present invention is to provide a
more convenient system for mixing bone cement in a vacuum in an
operating room environment.
[0008] Still another object of the present invention is to provide
an improved method for mixing bone cement.
[0009] Yet another object of the present invention is to provide a
more convenient method for mixing bone cement in a vacuum in an
operating room environment.
SUMMARY OF THE INVENTION
[0010] These and other objects of the present invention are
achieved through the provision and use of a novel system and method
for mixing bone cement.
[0011] The novel system for mixing bone cement generally comprises
(i) a container within which the constituent components of the bone
cement are mixed under vacuum; (ii) a vacuum pump for pulling a
vacuum; (iii) a vacuum line interconnecting the vacuum pump and the
container; (iv) a check valve disposed in the vacuum line for
maintaining a vacuum pulled in the container by the vacuum pump;
(v) a vacuum indicator disposed in the vacuum line for indicating
when a predetermined level of vacuum has been attained in the
container; and (vi) a filter disposed in the vacuum line for
preventing unwanted materials (e.g., powdered polymer and/or
copolymer, liquid monomer, and/or mixed cement) from passing from
the container to the check valve and/or vacuum pump.
[0012] In accordance with the present invention, the bone cement's
powdered polymer and/or copolymer component is pre-packaged in the
aforementioned container, and the bone cement's liquid monomer
component is pre-packaged in a separate holder.
[0013] In one form of the invention, the container can comprise a
sealed cartridge for a cement dispenser, or a sealed mixing bowl or
other vessel. The container comprises an injection port for
connection to the holder containing the bone cement's liquid
monomer component, an exhaust port for connection to the vacuum
line and hence the vacuum pump, and an agitator having a mixing
paddle disposed inside the sealed container and an actuating handle
disposed outside the sealed container, with a shaft connecting the
mixing paddle to the handle. Barrier means are disposed inside the
container, between the contents of the container and the exhaust
port. These barrier means comprise a plurality of indirect pathways
which permit gas to pass out of the container via the exhaust port
but prevent solid and/or liquid material from passing out of the
container via the exhaust port. Preferably, an absorbent filter is
disposed in the exhaust port, downstream from the barrier means but
upstream from the vacuum line, to trap any solid and/or liquid
material which might pass by the barrier means.
[0014] In another form of the invention, the container comprises a
sealed cartridge for a cement dispenser. This cartridge comprises
an exhaust port for connection to the vacuum line and hence the
vacuum pump, an agitator having a mixing paddle disposed inside the
sealed cartridge and an actuating handle disposed outside the
sealed cartridge, with a hollow shaft connecting the mixing paddle
to the handle, and an injection port for connection to the holder
containing the bone cement's liquid monomer component. In this form
of the invention, the injection port is disposed in the handle of
the agitator and communicates with the interior of the sealed
container through the agitator's hollow handle. A porous plug
closes off the distal end of the hollow handle, whereby liquid
monomer can pass from the injection port through to the interior of
the sealed container but powdered polymer and/or copolymer and/or
mixed cement will be prevented from passing out of the sealed
container through the agitator during cement mixing. Preferably the
agitator's shaft is formed out of a thin-walled exterior tube and a
resilient interior tube, with the thin-walled exterior tube
including a breakaway notch, and with the distal end of the
resilient interior tube being connected to the porous plug,
whereby, at the conclusion of cement mixing, the handle of the
agitator can be retracted relative to the container, the
thin-walled exterior tube can be broken off at the breakaway notch,
and the resilient interior tube can be used to withdraw the porous
plug from the remaining stub of the thin-walled exterior tube,
whereby the stub of the thin-walled exterior tube can become an
ejection port for the sealed cartridge.
[0015] In still another form of the invention, the container can
comprise a sealed cartridge for a cement dispenser, or a sealed
mixing bowl or other vessel. In this form of the invention, the
holder containing the bone cement's monomer component comprises a
glass ampoule having an easily fractured neck at one end. The
container comprises an injection port for connection (through
intervening elements) to the monomer ampoule, an exhaust port for
connection to the vacuum line and hence the vacuum pump, and an
agitator having a mixing paddle disposed inside the sealed
container and an actuating handle disposed outside the sealed
container, with a shaft connecting the mixing paddle to the handle.
The monomer ampoule is disposed in an ampoule breaker/injector
device which is connected to the container's injection port. The
apparatus is arranged so that when a vacuum is drawn in the sealed
container, the monomer ampoule will be automatically broken at its
easily fractured neck by forces generated by the vacuum and the
liquid monomer will then be drawn down into the sealed container
through the container's injection port.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] These and other objects and features of the present
invention will be more fully disclosed or rendered obvious by the
following detailed description of the preferred embodiments of the
invention, which are to be considered together with the
accompanying drawings wherein like numbers refer to like parts and
further wherein:
[0017] FIG. 1 is a schematic view of a system for mixing bone
cement;
[0018] FIG. 2 is a side view in section of the cap portion of the
container shown in FIG. 1;
[0019] FIG. 3 is a bottom view of the cap portion of the container
shown in FIG. 1;
[0020] FIG. 4 is a side view in section of the barrier means
associated with the container shown in FIG. 1;
[0021] FIG. 5 is a bottom view of the barrier means associated with
the container shown in FIG. 1;
[0022] FIG. 6 is a top view, partially in section, of the distal
end of the agitator associated with the container shown in FIG.
1;
[0023] FIG. 7 is a side view in section of one type of holder for
containing the bone cement's liquid monomer component, wherein the
holder comprises a syringe;
[0024] FIG. 8 is a side view of another type of holder for
containing the bone cement's liquid monomer component, wherein the
holder comprises a collapsible package;
[0025] FIG. 9 is a side view in section of still another type of
holder for containing the bone cement's liquid monomer component,
wherein the holder comprises an injector sleeve fit over the distal
end of a glass ampoule storing the liquid monomer component;
[0026] FIG. 10 is a side view in section of an alternative form of
container which can be used in conjunction with the system shown in
FIG. 1;
[0027] FIG. 11 is a side view in section of the agitator associated
with the container shown in FIG. 10;
[0028] FIG. 12 is a side view in section showing the distal end of
the agitator's thin-walled exterior tube being broken off, and the
agitator's resilient interior tube withdrawing the porous plug,
whereby the remaining stub of the thin-walled exterior tube can
become an ejection port for the sealed container;
[0029] FIG. 13 is a side view in section showing the ampoule
breaker/injector device connected to the injection port of a
container;
[0030] FIG. 14 is a partial side view of the proximal end of the
ampoule breaker/injector device shown in FIG. 13, except that the
view of FIG. 14 has been taken at a 90 degree angle to the view of
FIG. 13;
[0031] FIG. 15 is a side view in section like that of FIG. 13,
except that the glass ampoule storing the bone cement's liquid
monomer component is shown moved distally within the ampoule
breaker/injector device, with the distal end of the ampoule having
broken off to release the liquid monomer; and
[0032] FIG. 16 is a side view in section showing an alternative
form of ampoule breaker/injector device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] Looking first at FIG. 1, a system 5 for mixing bone cement
is shown. System 5 generally comprises a container 10 within which
the constituent components of the bone cement are mixed under
vacuum, a vacuum pump 15 for pulling a vacuum, a vacuum line 20
interconnecting vacuum pump 15 and container 10, one or more check
valves 25 disposed in vacuum line 20 for maintaining a vacuum
pulled in container 10, a vacuum indicator 30 disposed in vacuum
line 20 for indicating when a predetermined level of vacuum has
been attained in container 10, and a filter 35 containing activated
charcoal disposed in vacuum line 20 for absorbing unwanted monomer
fumes.
[0034] In accordance with the present invention, the bone cement's
powdered polymer and/or copolymer component is pre-packaged in
sealed container 10, and the bone cement's liquid monomer component
is pre-packaged in a separate holder.
[0035] Still looking now at FIG. 1, container 10 comprises a
container body 40 filled with the bone cement's powdered polymer or
copolymer component 45, a cap 50 for sealing off container body 40,
and an agitator 55 for mixing the bone cement's constituent
components within container 10.
[0036] For purposes of the present invention, container body 40 can
comprise a cartridge for a cement dispenser, in which case
container body 40 can be mounted directly in a cement dispenser
after the bone cement has been mixed under vacuum. Alternatively,
container body 40 can comprise a simple mixing bowl or other
vessel, in which case the bone cement is transferred to a cartridge
for a cement dispenser after the bone cement has been mixed in
container 10. In FIG. 1, container body 40 is shown to be a
cartridge for a cement dispenser, and to this end it includes a
drive plug 60 which can be urged down the length of container body
40 so as to eject cement from the cartridge, in ways well known in
the art.
[0037] Looking next at FIGS. 1-5, container cap 50 seals off the
distal end of container body 40 so as to form the sealed container
10. Cap 50 includes a cap housing 65, barrier means 70 (FIGS. 1, 4
and 5) disposed on the distal side of cap 50, an exhaust port 75
for connection to vacuum line 20, an absorbent filter 78 disposed
in exhaust port 75 for preventing unwanted materials (e.g.,
powdered polymer or copolymer, liquid monomer, and/or mixed cement)
from passing out of container 10 through exhaust port 75, and an
injection port 80 for connection to the holder containing the bone
cement's liquid monomer component.
[0038] Looking next at FIGS. 2 and 3, cap housing 65 includes an
opening 85 to receive the shaft 90 (FIG. 1) of agitator 55. Cap
housing 65 also includes an opening 95 which makes up part of
exhaust port 75, an opening 100 which makes up part of injection
port 80, and shallow surface grooves 105 (FIG. 3) which are formed
on the underside of cap housing 65. Surface grooves 105 cooperate
with barrier means 70 to provide "indirect pathways" between the
interior of container 10 and exhaust port 75, as will hereinafter
be discussed in further detail.
[0039] Looking next at FIGS. 1, 4 and 5, barrier means 70 are
disposed adjacent the distal side of cap housing 65. Barrier means
70 are formed out of a non-porous material such as polyethylene.
Barrier means 70 are formed in the shape of a thin disk and
includes a central hole 110 and a plurality of radial slits 115
(FIG. 5). Central hole 110 is sized so as to accommodate shaft 90
of agitator 55. Radial slits 115 cooperate with surface grooves 105
of cap housing 65 so as to define a plurality of indirect pathways
extending between the interior of container 10 and exhaust port 75.
These indirect pathways permit gas to pass out of container 10 via
exhaust port 75, whereby the interior of container 10 can be placed
into a vacuum condition, but prevent solid and/or liquid material
from passing out of container 10 via exhaust port 75. This helps
protect the one or more check valves 25 and/or the vacuum pump 15,
which elements are located downstream in vacuum line 20. Preferably
multiple indirect paths are provided, so that gas evacuation can
continue even if one or more paths become blocked with solids
and/or liquids.
[0040] Exhaust port 75 is a valved connector arrangement which
coacts with a counterpart connector arrangement 118 (FIG. 1)
disposed on the distal end of vacuum line 20 so as to permit vacuum
pump 15 to evacuate air from container 10. Connector arrangement
118, located on the distal end of vacuum line 20, and the
counterpart valved connector arrangement of exhaust port 75,
located on container 10, may comprise any one of the many connector
sets well known in the art. Such connector sets typically utilize a
male-female coupling, with the valved connector arrangement of
exhaust port 75 including some sort of check valve arrangement so
as to render exhaust port 75 self-sealing when it is not being
engaged by connector arrangement 118. By way of example, connector
arrangement 118 might comprise something equivalent to the blunt
inflation pump cannulas of the type commonly used to inflate an
ordinary basketball or football, and the valved connector
arrangement of exhaust port 75 might comprise something equivalent
to the rubber self-sealing inflation ports used on such basketballs
and footballs. Alternatively, the counterpart connectors might
comprise a Clave.TM. valve Needleless Connector (ICU Medical Inc.,
Irvine, Calif.), or an InterLink.TM. System (Baxter Healthcare
Corporation, Deerfield, Ill.) injection port with pre-slit septum
in combination with an InterLink.TM. cannula (Becton Dickinson
& Co., Franklin Lake, N.J.). For the purposes of the present
invention, the principal requirements for connector arrangement 118
and the valved connector arrangement of exhaust port 75 are that
(i) they are capable of making an airtight connection when they are
in engagement with one another, and (ii) the valved connector
arrangement of exhaust port 75 is self-sealing when connector
arrangement 118 (and hence the distal end of vacuum line 20) is
disconnected from container 10.
[0041] Absorbent filter 78 is disposed in exhaust port 75,
downstream from barrier means 70 but upstream from vacuum line 20.
Absorbent filter 78 serves to remove any material (e.g., powdered
polymer and/or copolymer, liquid monomer, and/or mixed cement) that
may get past the indirect pathways discussed above. Absorbent
filter 78 is preferably made from a cellulose material of the sort
well known in the art.
[0042] Injection port 80 is a valved connector arrangement which
coacts with a counterpart connector arrangement 119 (FIG. 7)
disposed on the distal end of a holder containing the bone cement's
liquid monomer component so as to permit liquid monomer to be
introduced into container 10. Connector arrangement 119, located on
the distal end of a holder containing the bone cement's liquid
monomer component, and the counterpart valved connector arrangement
of injection port 80, located on container 10, may comprise any one
of the many connector sets well known in the art. Such connector
sets typically utilize a male-female coupling, with the valved
connector arrangement of injection port 80 including some sort of
check valve arrangement so as to render injection port 80
self-sealing when it is not being engaged by connector arrangement
119. By way of example, connector arrangement 119 might comprise
something equivalent to the blunt inflation pump cannulas of the
type commonly used to inflate an ordinary basketball or football,
and the valved connector arrangement of injection port 80 might
comprise something equivalent to the rubber self-sealing inflation
ports used on such basketballs and footballs. Alternatively, the
counterpart connectors might comprise a Clave.TM. valve Needleless
Connector (ICU Medical Inc., Irvine, Calif.), or an InterLink.TM.
System (Baxter Healthcare Corporation, Deerfield, Ill.) injection
port with pre-slit septum in combination with an InterLink.TM.
cannula (Becton Dickinson & Co., Franklin Lake, N.J.). For the
purposes of the present invention, the principal requirements for
connector arrangement 119 and the valved connector arrangement of
injection port 80 are that (i) they are capable of making an
airtight connection when they are in engagement with one another,
and (ii) the valved connector arrangement of injection port 80 is
self-sealing when connector arrangement 119 (and hence the holder
containing the bone cement's liquid monomer component) is
disconnected from container 10.
[0043] Looking next at FIGS. 1 and 6, agitator 55 comprises a shaft
90 having a mixing paddle 120 disposed at its distal end and a
T-shaped handle 125 disposed at its proximal end. T-shaped handle
125 comprises a pair of lateral extensions 127. Agitator 55 is
disposed so that its shaft 90 extends through opening 85 in cap 50
and opening 110 in barrier means 70, whereby the agitator's mixing
paddle 120 can be urged to mix the cement components located in the
interior of sealed container 10 by means of handle 125. In
particular, agitator 55 is arranged so that reciprocal movement of
handle 125 relative to container 10 will cause mixing paddle 120 to
move in a reciprocal fashion within the interior of container
10.
[0044] Vacuum pump 15, vacuum line 20, the one or more check valves
25, vacuum indicator 30, and filter 35 are all preferably of the
sort disclosed in pending U.S. patent application Ser. No.
08/577698, filed Dec. 22, 1995 by Kwan-Ho Chan for VACUUM SYSTEM,
which application is hereby incorporated herein by reference.
Alternatively, vacuum pump 15, vacuum line 20, the one or more
check valves 25, vacuum indicator 30, and filter 35 can be
generally equivalent elements of the sort well known in the
art.
[0045] Looking next at FIG. 7, a holder 130 is shown for containing
the bone cement's liquid monomer component. Holder 130 comprises an
elongated cavity 135 for containing a supply of liquid monomer 140,
an egress port 145 terminating in a connector arrangement 119 of
the sort described above, and a sliding piston 155. Piston 155
closes off the rear end of elongated cavity 135 and has its
proximal surface 160 exposed to the ambient atmosphere. Piston 155
is adapted to make a close sliding fit with the walls of cavity
135, whereby piston 155 can move distally within cavity 135 as the
liquid monomer is withdrawn from the holder, as will hereinafter be
discussed in further detail.
[0046] System 5 can be used to mix bone cement as follows. First,
holder 130 (FIG. 7) is connected to the sealed container's
injection port 80. This is done by engaging connector arrangement
119 of monomer holder 130 with the valved connector arrangement of
injection port 80 (FIG. 1). Then vacuum line 20 is connected to
evacuation port 75. This is done by engaging connector arrangement
118 of vacuum line 20 with the valved connector arrangement of
evacuation port 75 (FIG. 1). Then vacuum pump 15 is used to pull a
vacuum in container 10, whereby the air present in container 10
will be evacuated from the container, and whereby liquid monomer
140 (FIG. 7) stored in holder 130 will be drawn into container 10
and into contact with the powdered polymer and/or copolymer stored
in container 10. Next agitator 55 is used to mix liquid monomer 140
with the powdered polymer and/or copolymer 45 (FIG. 1) so as to
form the desired bone cement. The vacuum line 20 may be
disconnected from the container's exhaust port 75 before or after
mixing. The mixed cement is then ready to be used, either directly
in container 10 if the container is the form of a cartridge for a
cement dispenser, or by transferring the mixed cement from
container 10 into a cartridge for a cement dispenser if container
10 is a simple mixing bowl or other vessel.
[0047] Looking next at FIG. 8, another holder 165 is shown for
containing the bone cement's liquid monomer component. Holder 165
comprises a collapsible package 170 having an egress port 175
terminating in a connector arrangement 119 of the sort described
above. With the arrangement of holder 165, when holder 165 is
connected to container 10 and a vacuum is then drawn in container
10, ambient atmospheric pressure will act on collapsible package
170 so as to cause the liquid monomer to pass out of holder 165 and
into container 10.
[0048] Looking next at FIG. 9, yet another holder 185 is shown for
containing the bone cement's liquid monomer component. Holder 185
comprises an injector sleeve 190 which is fit over the distal end
of a glass ampoule 195.
[0049] Injector sleeve 190 includes an egress port 200 terminating
in a connector arrangement 119 of the sort described above. O-rings
205 are disposed in the inside side wall of injector sleeve 190, to
make an airtight seal with ampoule 195.
[0050] Ampoule 195 has a traditional configuration which includes
an easily fractured neck at one end. Ampoule 195 holds the bone
cement's liquid monomer component 140. In addition, and quite
significantly, ampoule 195 also preferably holds a gas column 210.
Gas column 210 is provided to facilitate withdrawal of the monomer
component from the fixed volume glass ampoule vessel by a vacuum.
In fact, when ampoule 195 is in communication with container 10 and
a vacuum is thereafter drawn in that container, gas column 210 will
effectively expand in the ampoule as the vacuum is drawn in the
container until the pressure of gas column 210 in ampoule 195
equilibrates with the level of the vacuum in container 10. Thus,
the expanding gas column 210 effectively expels monomer 140 from
ampoule 195 and into container 10 as a vacuum is established in
container 10.
[0051] The minimum volume of gas required to completely expel
monomer 140 from ampoule 195 under the influence of the vacuum in
container 10 is governed by Boyle's Law, as follows:
V.sub.o.times.P.sub.o=(V.sub.M+V.sub.o).times.P.sub.c
[0052] where:
[0053] V.sub.o=volume of gas in ampoule 195
[0054] P.sub.o=pressure of gas in ampoule 195
[0055] V.sub.M=volume of monomer in ampoule 195
[0056] P.sub.c=vacuum level in container 10 (assumed to be
constant).
[0057] By way of example, suppose the volume of monomer in ampoule
195 (i.e., V.sub.M) is 40 cc, the pressure of gas in ampoule 195
(i.e., P.sub.o) is 30 mm Hg, the ambient atmospheric pressure is 30
mm Hg, the vacuum in container 10 (i.e., P.sub.c) is 22 mm HG below
ambient atmospheric pressure
[0058] (i.e., 30 mm HG-22 mm HG=8 mm HG), then
V.sub.o.times.30=(40+V.sub.o).times.8
[0059] or
V.sub.o=14.5 cc
[0060] In practice, since the surface tension of monomer 140 is
very low, the monomer will tend to flow out of ampoule 195 under
the influence of gravity alone. In other words, the monomer will
flow out of ampoule 195 even if the minimum volume of gas required
to completely expel monomer 140 from ampoule 195 is not met.
Monomer 40 will, of course, flow out of ampoule 195 much better
when the volume and pressure requirement are met. And, as might be
expected, the system will work best if gas column 210 is sealed in
ampoule 195 under pressure.
[0061] In use, the easily fractured neck of ampoule 195 is broken
off by snapping it along a prescored line which is provided for
this purpose. This effectively opens ampoule 195. Next injector
sleeve 190 is slipped over the open end of glass ampoule 195.
O-rings 205 seal vessel 195 within injector sleeve 190. On account
of this construction, when holder 185 is connected to container 10
and a vacuum is then drawn in container 10, the gas column 210
disposed above liquid monomer 140 will expand so that the liquid
monomer will flow out of the holder and into container 10. In this
respect it is also to be appreciated that, when holder 185 is
connected up to container 10 and a vacuum is then drawn in
container 10, atmospheric pressure acting on the top surface 220 of
glass ampoule 195 will urge the ampoule further down into injector
sleeve 190, if the ampoule is not already maximally advanced into
the injector sleeve.
[0062] Looking next at FIGS. 10-12, an alternative container 10A is
disclosed which can be used in place of the container 10 in system
5. Container 10A is identical to the container 10 previously
disclosed, except as will hereinafter be discussed.
[0063] First, container 10A is generally intended to comprise a
container body 40A which is in the form of a cartridge for a cement
dispenser. Container body 40A is generally not intended to be in
the form of a sealed mixing bowl or other non-cartridge vessel, as
might be the case with the container body 40 previously disclosed.
Of course, it should also be appreciated that nothing in the
present invention requires that container body 40A be in the form
of a cartridge for a cement dispenser; it is merely anticipated
that this will be the most useful form for container body 40A.
[0064] Second, container 10A has a cap 50A which is identical to
the cap 50 previously disclosed, except that cap 50A omits the
injection port 80 previously disclosed in connection with container
10. Furthermore, if desired, the indirect pathways of container 10
(constituted by the surface grooves 105 formed in the cap's bottom
surface and by the radial slits 115 formed in barrier means 70) may
be omitted in container 10A. In such a case, alternative barrier
means 70A may be provided, wherein such barrier means 70A are
formed out of a porous or semi-porous material such that barrier
means 70A can serve to minimize any undesired materials (e.g.,
powdered polymer and/or copolymer, liquid monomer, and/or mixed
cement) from passing into the container's exhaust port 75, while
still permitting gas to be evacuated from container 10A through
exhaust port 75.
[0065] Third, container 10A includes an agitator 55A which differs
significantly from the agitator 55 previously disclosed in
connection with container 10. Agitator 55A comprises a thin-walled
exterior tube 225 having a breakaway notch 230 (FIGS. 10 and 11)
formed near its distal end, a resilient interior tube 235 disposed
inside the thin-walled exterior tube 225, a perforated disk 240
disposed at the distal end of thin-walled exterior tube 225 and
resilient interior tube 235, a porous plug 245 closing off the
distal end of resilient interior tube 235, a T-shaped handle 250
connected to the top ends of thin-walled exterior tube 225 and
resilient interior tube 235, and an injection port 255 formed in
handle 250.
[0066] Thin-walled exterior tube 225 is formed out of breakable
plastic, e.g., polyethylene. Breakaway notch 230 is formed near the
distal end of thin-walled exterior tube 225, and preferably
comprises a peripheral groove formed in the outer surface of the
tube. Breakaway notch 230 permits thin-walled exterior tube 225 to
be broken off in a snapping action, as will hereinafter be
discussed in further detail.
[0067] Resilient interior tube 235 is disposed within thin-walled
exterior tube 225. Interior tube 235 is formed out of a resilient
material which will flex but remain intact when thin-walled
exterior tube 225 is broken off at its breakaway notch 230 in a
snapping motion. At the same time, however, interior tube 235 is
formed out of a material which is sufficiently rigid in an axial
direction such that porous plug 245 will remain securely in place
within agitator 55A when the agitator is used to mix bone cement
within container 10A, as will hereinafter be discussed in further
detail. Resilient interior tube 235 is preferably formed out of
plasticized polyvinylchloride (PVC) or silicone.
[0068] Perforated disk 240 is identical to the perforated disk 120
described above in connection with agitator 55, except that
perforated disk 240 includes an opening 260 (FIGS. 11 and 12) at
its center. Opening 260 in perforated disk 240 receives, and is
joined to, the distal end of thin-walled exterior tube 225 (FIGS.
10 and 11), whereby the thin-walled exterior tube 225 can be used
to move perforated disk 240 distally and proximally within
container 10A so as to mix the contents of container 10A. As such
mixing occurs, the distal end of resilient interior tube 235 and
porous plug 245 will be exposed to the contents of container 10A
(FIGS. 10 and 11).
[0069] Porous plug 245 closes off, and is securely fastened to, the
distal end of resilient inner tube 235. Porous plug 245 is formed
so that it will prevent powdered polymer and/or copolymer material
from getting into the central passageway of resilient inner tube
235, yet still permit air and liquid monomer to pass through the
plug. In this way, the creation of a vacuum within the body of
container 10A can be used to draw liquid monomer downward from
injection port 255, whereby the liquid monomer will pass down the
length of resilient interior tube 235, through porous plug 245 and
then enter the interior of container 10A.
[0070] Handle 250 is secured to both thin-walled exterior tube 225
and resilient interior tube 235. As a result, handle 250 can be
used to move the agitator's perforated disk 240 in a reciprocal
motion within the interior of container 10A, yet can also be used
to withdraw resilient interior tube 235 and porous plug 245 from
container 10A once the thin-walled exterior tube 225 has been
snapped off along its breakaway notch 230, as will hereinafter be
discussed in further detail. Handle 250 preferably comprises a pair
of lateral extensions 265 (FIG. 10).
[0071] Injection port 255 is formed in handle 250. Injection port
255 comprises a valved opening for introducing liquid monomer into
the interior passageway of resilient interior tube 235. To this
end, injection port 255 comprises a valved connector arrangement of
the sort adapted to form an airtight seal with its counterpart
connector arrangement 119 formed on a monomer holder, e.g. a holder
such as holder 130 (FIG. 7), holder 165 (FIG. 8) and/or holder 185
(FIG. 9). In particular, injection port 255 in container 10A can be
substantially the same as the injection port 80 disclosed in
connection with container 10 except, of course, for the fact that
injection port 255 is formed in handle 250 and provides an entryway
to the interior of resilient interior tube 235, whereas the
injection port 80 associated with container 10 is disposed in that
container's cap 50 and opens directly on the interior of that
container.
[0072] It is to be noted that the sealed container 10A is
pre-filled with an appropriate supply of the bone cement's powdered
polymer and/or copolymer component.
[0073] Container 10A is intended to be used with system 5 as
follows. First, a monomer holder (e.g., a monomer holder 130 as
shown in FIG. 7, or a monomer holder 165 as shown in FIG. 8, or a
monomer holder 185 as shown in FIG. 9, or some other such holder)
is connected to the injection port 255 formed in handle 250. This
is done by engaging connector arrangement 119 of the monomer holder
with the valved connector arrangement of injection port 255 so as
to establish an airtight connection. Then vacuum line 20 is
connected to the container's evacuation port 75. This is done by
engaging connector arrangement 118 (FIG. 1) of vacuum line 20 with
the valved connector arrangement of evacuation port 75 so as to
establish an airtight connection. Next, a vacuum is pulled in
container 10A using vacuum pump 15. This vacuum draws the bone
cement's liquid monomer component out of its holder and down the
interior passageway of resilient interior tube 235, whereupon the
liquid monomer component passes through porous plug 245 and enters
the interior of container 10A to join the bone cement's powdered
polymer and/or copolymer component. Then the monomer holder is
disconnected from injection port 255, and agitator 55A is used to
mix the cement in container 10A by moving perforated disk 240 back
and forth within the container. Next, vacuum line 20 is
disconnected from container 10A, and agitator 55A is retracted
relative to container 10A (i.e., agitator 55A is moved so that its
perforated disk 240 resides adjacent to barrier means 70 or 70A,
depending on which type of barrier means may be provided). Then the
proximal end of thin-walled exterior tube 225 is snapped off at
breakaway notch 230 so as to provide a stub 266 (FIG. 12), and the
proximal end of agitator 55A is withdrawn from container 10A,
carrying resilient interior tube 235 and porous plug 245 away from
the container 10A. This leaves hollow stub 266 clear and the
container 10A ready to be loaded into a cement dispenser of the
sort well known in the art, whereupon the mixed cement within
container 10A can be dispensed out the hollow stub 266. Preferably
breakaway notch 230 on the thin-walled exterior tube 225 is
positioned such that stub 265 will lie substantially flush with a
cap projection 267 (FIGS. 10 and 12) after the proximal end of
agitator 55A is removed from container 10A, whereby various nozzle
fixtures can be easily mounted to cap projection 267 so as to
facilitate dispensing of bone cement.
[0074] Looking next at FIGS. 13-15, another container arrangement
270 is shown which can be used with system 5. Container arrangement
270 comprises a container 10 of the sort previously described and
shown in FIGS. 1-6, and an ampoule breaker/injector 275 which is
connected to the container's injection port 80. Ampoule
breaker/injector 275 is arranged so that it will automatically (i)
break a glass ampoule 195 of the sort shown in FIGS. 9 and 13 when
a vacuum is established in container 10, and (ii) direct the
released monomer liquid into the container's injection port 80.
More particularly, ampoule breaker/injector 275 acts as a caddy for
the ampoule 195 until a vacuum is to be drawn in container 10 and
the liquid monomer in the ampoule is to be used, at which time
ampoule breaker/injector 275 facilitates release of the liquid
monomer from the ampoule, and then directs the liquid monomer
through the container's injection port 80 and into contact with
powdered polymer and/or copolymer powder previously packaged in the
sealed container 10. The volume of the gas column used to
efficiently expel the liquid monomer from the ampoule is as
previously described in connection with the arrangement shown in
FIG. 9.
[0075] Ampoule breaker/injector 275 comprises an elongated body
280, a connector arrangement 119 disposed at the distal end of body
280, an internal wedge 290 set near the distal end of body 280, a
glass trap 295 disposed between wedge 290 and connector arrangement
119, and a proximal piston 300 having an associated O-ring 305. A
U-shaped groove 310 is formed in the proximal end of body 280, as
will hereinafter be disclosed in further detail.
[0076] Elongated body 280 is adapted to support glass ampoule 195
so that it is axially aligned with container 10, and so that the
ampoule can make a sliding fit within the interior of elongated
body 280.
[0077] Connector arrangement 119 is disposed at the distal end of
elongated body 280. Connector arrangement 119 is in fluid
communication with the interior of elongated body 280. As discussed
above, connector arrangement 119 is of the sort adapted to form an
airtight seal with the valved connector arrangement of injection
port 80, as also discussed above.
[0078] Internal wedge 290 is set near the distal end of elongated
body 280. Wedge 290 is fixed to the internal side wall of elongated
body 280. Wedge 290 is set at an angle to the longitudinal axis of
the elongated body, whereby the leading tip of a glass ampoule 195
located within elongated body 280 will break off when that ampoule
is driven distally against wedge 290. In essence, wedge 290
translates the distal movement of glass ampoule 195 into the
lateral movement used to break off the leading tip of the ampoule
and release its liquid monomer.
[0079] Glass trap 295 is disposed within elongated body 280,
between internal wedge 290 and connector arrangement 119. Glass
trap 295 permits liquid monomer (released by the broken ampoule
195) to pass through to connector arrangement 119, whereupon the
liquid monomer will enter the interior of container 10; at the same
time, however, glass trap 295 prevents glass chards from the broken
ampoule from reaching the bone cement's powder polymer and/or
copolymer component which is disposed in container 10.
[0080] Piston 300 is disposed in the proximal end of elongated body
280, so that the piston's O-ring 305 is positioned on the distal
side of U-shaped groove 310. The piston's associated O-ring 305
forms an airtight seal with the interior wall of elongated body
280. The distal end surface 312 (FIG. 13) of piston 300 contacts
the proximal end surface 315 of ampoule 195. The O-ring 305 is
disposed distal to the lowest point of the U-shaped groove 310.
[0081] As a result of the foregoing construction, when a vacuum is
drawn within container 10 using vacuum pump 15, this vacuum will
extend up into the interior of elongated body 280, thereby urging
piston 300 to travel distally within elongated body 280. The moving
piston 300 in turn drives ampoule 195 distally, so that the leading
nose of the glass ampoule is driven against internal wedge 290,
thereby breaking off at the prescored neck of the ampoule and
releasing the liquid monomer contained in the ampoule. This liquid
monomer is then drawn down into container 10 by the same vacuum,
whereby the monomer will mix with the powdered polymer and/or
copolymer previously packed into container 10. Preferably ampoule
195 includes the gas column 210 previously discussed.
[0082] Preferably, piston 300 has an enlarged cross-section
relative to ampoule 195, as shown in FIGS. 13-15, so as to generate
greater driving force on the top end of the ampoule.
[0083] U-shaped groove 310 is formed at the proximal end of
elongated body 280 (FIGS. 13 and 14). Groove 310 is sized so as to
accept one of the lateral extensions 127 of handle 125. Preferably
the top end of groove 310 is narrowed slightly as shown at 325
(FIG. 14) so as to releasably hold a lateral handle extension 127
in groove 310. The positioning of a lateral handle extension 127 in
groove 310 serves to stabilize the proximal end of elongated body
280 relative to agitator shaft 90.
[0084] Furthermore, since the agitator's handle 125 will tend to be
drawn downward as a vacuum is drawn in container 10, groove 310
provides a guide for one of the distally-moving lateral handle
extensions 127. Additionally, since groove 310 permits one of the
lateral handle extensions 127 to remain in engagement with the top
of the distally-moving piston 300, the force generated by the
moving lateral handle extension 127 will combine with the force
generated by the moving piston 300 so as to assist in the breakage
of glass ampoule 195. Furthermore, in the event that the vacuum
created in container 10 is unable to drive piston 300 distally with
sufficient force to break the glass neck of the ampoule, the
presence of groove 310 permits the user to manually depress handle
125 so as to increase the distal pressure applied to the ampoule,
whereby ampoule 195 can be broken.
[0085] The container arrangement shown in FIGS. 13-15 is intended
to be used as follows. First ampoule breaker/injector 275 is
connected to the container's injection port 80. This is done by
engaging connector arrangement 119 of ampoule breaker/injector 275
with the valved connector arrangement of injection port 80. Then an
ampoule 195 is loaded into the interior of elongated body 280. Next
piston 300 is set atop ampoule 195. Then one of the lateral
extensions 127 of handle 125 is set in U-shaped groove 310, so that
the lateral extension contacts the top surface of piston 300. Next
vacuum line 20 is connected to exhaust port 75 on container 10 (not
shown in FIGS. 13-15, but shown in FIGS. 1 and 2). This is done by
engaging connector arrangement 118 of vacuum line 20 with the
valved connector arrangement of exhaust port 75. Then a vacuum is
pulled in container 10, using vacuum pump 15. Creation of a vacuum
within the interior of container 10 causes piston 300 to move
distally within elongated body 280, driving the distal end of
ampoule 195 against internal wedge 290. At the same time, creation
of a vacuum within container 10 causes agitator 55 to move
distally, whereupon the lateral extension 127 of handle 125
disposed in groove 310 will bring additional distally-directed
force to bear on the proximal end of piston 300. Additionally,
further downward force can be applied to the proximal end of
ampoule 195 by manually pressing down on handle 125 if necessary.
As a result of the foregoing, the distal end of ampoule 195 will be
driven against internal wedge 290 so that the ampoule's glass neck
will be broken off, thereby releasing the liquid monomer contained
in ampoule 195 (FIG. 15). This monomer liquid will then pass down
into the interior of container 10, where it will come into contact
with the bone cement's powdered polymer and/or copolymer component
which was previously packaged in the sealed container. Then ampoule
breaker/injector 275 is dismounted from container 10 and the liquid
and solid cement components disposed in container 10 are mixed
together using agitator 55. Finally vacuum line 20 is disconnected
from the container's exhaust port 75. The mixed cement is then
ready to be used, either directly in container 10 if container 10
is in the form of a cartridge for a cement dispenser, or by
thereafter transferring the mixed cement from container 10 into a
cartridge for a cement dispenser if the container 10 is a simple
mixing bowl or other non-cartridge vessel.
[0086] Looking next at FIG. 16, an alternative form of ampoule
breaker/injector 275A is shown. Ampoule breaker/injector 275A is
similar to the ampoule breaker/injector 275 previously disclosed,
except that the proximal end of elongated body 280A does not have
an enlarged cross-section relative to the middle portion of the
elongated body, and piston 300 has been replaced by one or more
O-rings 330 mounted in annular grooves formed in the side wall of
elongated body 275A. O-rings 330 make a close sliding fit with the
outside wall of glass ampoule 195. O-rings 330 are disposed distal
to the lowest point of the U-shaped groove 310. With the
arrangement shown in FIG. 16, application of a vacuum to connector
arrangement 119 will create a vacuum within the space 335 in the
assembly, thereby causing ampoule 195 to move distally against
wedge 290 so as to break the leading neck of the glass ampoule and
thereby release the monomer fluid held therein.
Modifications of the Preferred Embodiments
[0087] It is, of course, possible to modify the preferred
embodiments disclosed above without departing from the scope of the
present invention.
[0088] Thus, for example, one could substitute a plurality of
perforated holes for the radial slits formed in barrier means
70.
[0089] Or one could substitute a rotary-type agitator for the
reciprocal-type agitator disclosed above. With such an alternative
arrangement, the agitator's paddle element would move
circumferentially about the perimeter of the container, rather than
back and forth along its length.
[0090] Furthermore, one could use another type of barrier means
with the container 10 shown in FIGS. 13-15, e.g., one could use the
porous or semi-porous barrier means 70A previously discussed in the
context of container 10A.
[0091] Also, ampoule breaker/injector 275 or ampoule
breaker/injector 275A could be used with container 10A if desired,
in which case the monomer would be injected into the handle of the
agitator.
[0092] Still other modifications will be obvious to a person
skilled in the art, and are considered to fall within the scope of
the present invention.
Advantages of the Invention
[0093] Significant advantages are achieved through the use of the
present invention.
[0094] For one thing, the present invention provides an improved
system for mixing bone cement.
[0095] For another thing, the present invention provides a more
convenient system for mixing bone cement in a vacuum in an
operating room environment.
[0096] And the present invention provides an improved method for
mixing bone cement.
[0097] Additionally, the present invention provides a more
convenient method for mixing bone cement in a vacuum in an
operating room environment.
* * * * *