Note: Descriptions are shown in the official language in which they were submitted.
CA 02259530 2005-06-10
APPARATUS FOR CLEANSING TISSUE
F1EI~ OF THE INVENTION
The present invention relates to the treatment of living tissue, in general,
and to the
cleansing of exposed living tissue, in particular.
BACKGROUND OF THE INVENTION
The cleansing of exposed in vivo tissue, such as of humans or animals during
surgical procedures, requires the removal from the tissue of solid
contaminants, such as
fibers, dust, sand particles, and the tike, and organic matter, such as puss,
fats, and so on.
Organic matter tends to be fastened to the tissue much more strongly than the
non-organic
matter, and is thus more difficult to remove therefrom- Accordingly, while non-
organic matter
may be cleansed from the tissue by means of a liquid stream, it is often not
possible to
remove some organic matter in this way. Mace specifically, and most
problematic, are those
particles which are smaller than the thickness of the boundary. layer of the
fluid stream
which is formed on the tissue; the boundary layer being characterized by
having a fluid
velocity which reduces sharply adjacent to the flow surface, and which is -
zero at the
surface.
The smallest particles, which are located in the boundary layer, exhibit drag
resistance of a magnitude that is suffiaent for them to stay affixed to the
surface and not to
be swept away by the fluid stream, even if this has a very high velocity.
In an attempt to solve this problem, there have been developed a number of
prior art
devices which employ pulsed washing streams, such as described in USP
4,350,158 and
4,982,730. These pulsed stream devices operate on the basis of providing a
liquid stream
with a reduced boundary layer thickness, in order to sweep away small
particles. These
devices, however, generally have complicated constructions, use very large
quantities of
liquid, and have been found to provide only a small improvement over non-
pulsed devices.
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SUMMARY OF THE INVENTION
The present invention seeks to provide a method of and apparatus for cleansing
living tissue, such as during surgical procedures on humans and animals, and
which
overcome disadvantages of known art.
More specifically, it is sought to provide a cleansing method and apparatus
which
apply to the tissue surface a sterile liquid in a manner which is capable of
removing even
very small contaminants, thereby providing more effective cleansing of tissue
than known in
the art.
Furthermore, the cleansing is performed using relatively small amounts of
liquid,
thereby being not only more efficient and less wasteful than known methods,
but also being
more convenient and less messy to use than known methods.
The method of the invention is further characterized by having a therapeutic
effect
on the tissue being cleansed.
There is thus provided, in accordance with a preferred embodiment of the
invention,
apparatus employing liquid and gas as working fluids for cleansing living
tissue, which
includes:
a container for a sterile liquid;
a fluid delivery head having a liquid entry port and a gas entry port, fluid
outlet
apparatus, and valve apparatus located between the entry ports and the fluid
outlet
apparatus and for selectably permitting respective liquid and gas flows from
the entry ports
to the fluid outlet apparatus;
liquid conduit apparatus extending between a liquid inlet located within the
container
and a liquid outlet connected to the liquid entry port of the delivery head;
gas conduit apparatus extending between a gas inlet and a gas outlet, wherein
the
gas inlet is connected to a source of pressurized gas and the gas outlet is
connected to the
gas entry port of the delivery head, and wherein the gas conduit apparatus is
connected to
the container via an intermediate outlet port; and
apparatus for selectably exposing the source of sterile liquid to a flow of
pressurized
gas flowing from the gas inlet to the gas outlet and into the gas entry port
of the fluid
delivery head, thereby to pump the sterile liquid along the liquid conduit
apparatus, from the
inlet to the outlet, and into the liquid entry port of the fluid delivery
head,
wherein the fluid outlet apparatus comprises a gas-liquid combining member
arranged to receive the gas and liquid flows and to combine them into a gas-
liquid outflow
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which is operative to exit the apparatus through the fluid outlet in the form
of a sterile liquid
mist suspended in a high velocity gas stream.
Additionally in accordance with a preferred embodiment of the invention, the
gas
flow exits the valve apparatus into the gas-liquid combining member at a
pressure of a first
magnitude, and the combining member is operative to cause a pressure drop in
the gas
flow therethrough such that the pressure of the g<~s-liquid outflow downstream
of the fluid
outlet, is of a second magnitude, wherein the firsl: magnitude is at least
twice the second
magnitude, so as to cause a shock wave in the gas-liquid flow downstream of
the fluid
outlet and atomizing of the liquid portion of the outi9ow into microscopic
droplets, thereby to
form a mist suspended in the gas portion of the outflow.
Further in accordance with a preferred embodiment of the invention, the fluid
outlet
apparatus also includes apparatus for applying a suction force to the tissue
being cleansed.
Additionally in accordance with a preferredl embodiment of the invention, the
fluid
outlet apparatus further includes an interior nozzle member arranged to
provide an outflow
of sterile liquid, and the nozzle member includes:
a rear portion configured to fit over the intE~rior nozzle member and arranged
to fit
over the interior nozzle member so as to define a passageway therebetween for
the gas
flow;
a waist portion defined by a forward taperingi of the rear portion;
a front portion defining an opening and tapering rearwardly towards the waist
portion,
wherein the passageway is formed so as to be increasingly constricted towards
the
front portion of the nozzle, such that the gas flow passing through the
passageway is
accelerated to at least sonic velocity,
and wherein the front portion widens towards the opening thereof such that the
accelerated gas flow expands and thus undergoes a drop to a pressure which is
subatmospheric, such that, when the nozzle opening is brought close to tissue
contaminated by pollutant particles, the particles are exposed to the
subatmospheric
pressure so as to be loosened thereby from the tissue.
y Preferably, the gas-liquid outflow, downstream of the fluid outlet, has a
near-sonic
velocity.
Further in accordance with a preferred embodiment of the invention, the gas
inlet of
the gas conduit apparatus is constructed for connE:ction to a pressurized
oxygen source,
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and the outflow is an outflow of the sterile liquid mist suspended in a high
velocity oxygen
stream.
In accordance with a further preferred embodiment of the invention, there is
provided a method of cleansing living tissue, which includes:
exposing a source of sterile liquid to a flow of pressurized gas, thereby to
cause a
pumped supply thereof into a fluid delivery head;
supplying the pressurized gas to the fluid delivery head;
combining the gas and liquid supplied to the delivery head so as to provide a
gas-liquid outflow in the form of a sterile liquid mist suspended in a high
velocity gas stream;
and
exposing the living tissue to the gas-liquid outflow, thereby to remove
therefrom
contaminants.
Additionally in accordance with a preferred embodiment of the invention, the
step of
supplying the pressurized gas includes supplying the gas at a pressure of a
first magnitude,
and the step of combining includes causing a pressure drop in the gas flow
such that the
pressure of the gas-liquid outflow, is of a second magnitude, wherein the
first magnitude is
at least twice the second magnitude, so as to cause a shock wave in the gas-
liquid outflow
and atomizing of the liquid portion of the outflow into microscopic droplets,
thereby to form a
mist suspended in the gas portion of the outflow.
Further in accordance with a preferred embodiment of the invention, the method
also includes, prior to the step of combining, providing a gas outflow;
causing an expansion
of the gas outflow, thereby to cause a reduction in the pressure thereof to
subatmospheric
pressure, thereby provide a suction force; and providing a liquid outflow in
conjunction with
the expanded gas outflow.
In accordance with yet a further preferred embodiment of the invention, there
is
provided a method of cleansing and healing damaged living tissue, which
includes:
exposing a source of sterile liquid to a flow of pressurized oxygen, thereby
to cause
a pumped supply thereof into a fluid delivery head;
supplying the pressurized oxygen to the fluid delivery head;
combining the oxygen and liquid supplied to the delivery head so as to provide
a
oxygen-liquid outflow in the form of a sterile liquid mist suspended in a high
velocity oxygen
stream; and
exposing the damaged tissue to the oxygen-liquid outflow, thereby to remove
contaminants from the tissue, to prevent its drying out, and to cause healing
thereof.
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BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be more easily understood and appreciated from the
following detailed description, taken in conjunction with the drawings, in
which:
Fig. 1 is a general view of the liquid-gas apparatus of the present invention;
Fig. 2A is an enlarged, part-sectional side view of the container seen in Fig.
1;
Fig. 2B is an enlarged cross-sectional view of the distributor cap of the
container of
Fig. 2A, taken along line B-B therein;
Fig. 3A is a detailed cross-sectional view of the fluid delivery head seen in
Fig. 1,
when in use;
Fig. 3B is an enlarged detailed illustration of a portion of the valve
mechanisms, in
open positions;
Fig. 3C is an enlarged detailed illustration of a portion of the valve
mechanisms, in
closed positions;
Fig. 4 is a partial side view of a fluid delivery head constructed in
accordance with an
alternative embodiment of the invention, and having a nozzle portion which is
configured to
create a suction pressure in its immediate vicinity; and
Fig. 5 is an enlarged diagrammatic side-sectional view of the nozzle of the
fluid
delivery head seen in Fig. 4, showing the formation of the suction pressure
thereby.
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DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
Referring now to Fig. 1, the present invention provides apparatus, referenced
generally 10, which employs liquid and gas as working fluids for cleansing
living tissue,
such as human or animal tissue during surgical procedures. It will be
appreciated from the
following description that the present apparatus is characterized by being
highly efficient for
the removal of contaminant particles from living tissue, including very small
particles which
cannot be removed by previously known methods. The present apparatus further
uses
relatively small quantities of liquid, and thus, while serving to cleanse
tissue and to prevent
it from becoming dry during surgical procedures, it does not create
accumulations of large
quantities of liquid in the operating area. The use of oxygen, moreover, has
therapeutic
effects, which are well known, per se. In addition, the use of oxygen as a gas
source
renders the apparatus useful not only in the operating room, but in any
hospital facility
having a standard oxygen supply outlet.
Apparatus 10 includes a container 12 for containing a supply of a sterile
liquid, such
as any suitable saline solution, such as a 0.9% sodium chloride solution
suitable for
irrigation, and a fluid delivery head 14. Referring now also to Fig. 3A, head
14 has a liquid
entry port 16, a gas entry port 18, and fluid outlet apparatus 20, via which a
gas and liquid
mist outflow is provided, at near sonic velocity. It is this outflow which is
used for cleansing.
as described below.
By way of example, container 12 may be closed by means of a five-way
distributor
cap 22, which is fastened to the container as by means of a screw thread (not
shown), or by
a snap-type or other suitable coupling. Referring now also to Figs. 2A and 2B,
distributor
cap 22 has a gas inlet port 24, first and second gas outlet ports,
respectively referenced 26
and 28 (Figs. 1 and 2B), a liquid inlet port 30, and a liquid outlet port 32.
A first gas conduit 34 has an inlet end 36, which is preferably removably
coupled, via
an oxygen plug 38, to an oxygen outlet 40, together defining a connection such
as the
"Silberman 2000" oxygen connection, well known and found in many hospitals in
Israel and
worldwide, and which has associated therewith a central, high pressure oxygen
supply.
Preferably, the oxygen supply has a generally steady, non-pulsating pressure
head, of
approximately 3 atm. First gas conduit 34 also has an outlet end 42 which is
attached, via a
suitable screw or snap coupling 44, to gas inlet port 24. A second gas
conduit, referenced
46, has an inlet end 48 and an outlet end 50. Inlet end 48 is attached, via a
coupling 52,
similar to coupling 44, to first gas outlet port 26, and outlet end 50 is
attached, via suitable
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coupling 54, also similar to coupling 44, to an entry port 18' of a secondary
gas conduit 19,
coupled to gas entry port 18 of delivery head 14, as shown in Fig. 3A.
A liquid conduit 56 has an inlet end 58 which is attached, via a coupling 59,
similar
to coupling 44, to liquid outlet port 32 of distributor cap 22, and, further,
has an outlet end
60 which is attached, as by a suitable coupling 62, also similar to coupling
44, to an entry
port 16' of a secondary liquid conduit 17, coupled to liquid entry port 16 of
delivery head 14,
as shown in Fig. 3A.
A further tube portion, referenced 66, (Figs. 1 and 2A) is attached to liquid
inlet port
30 of distributor cap 22, and has a free end 68, extE:nding towards the floor
of container 12,
and which defines a liquid inlet 70.
As seen in Figs. 2A and 2B, distributor cap 22 is formed such that gas inlet
port 24 is
connected with first and second gas outlet ports 2~3 and 28, thereby to
facilitate a flow of
gas from first gas conduit 34 (Fig. 1), through cap c:2, and into second gas
conduit 46 (Fig.
1), while also facilitating a pressurized supply of gas into container 12, via
second gas outlet
port 28. Liquid inlet port 30 and liquid outlet port 32 are also connected to
each other, as
seen, although the gas and liquid flows through the .distributor cap 22 are
kept separate.
It will thus be appreciated that, when gas flow through the first and second
gas
conduits 34 and 46 is permitted, by appropriate adjustment of thumb-operated
levers 72 of
delivery head 14 (described below), a portion of the pressurized gas enters
container 12 via
second gas outlet port 28, thereby to pressurize the liquid in the container.
This increase in
pressure, coupled with a pressure difference between the interior of the
container and the
outlet apparatus 20 of the delivery head 14, causes an outflow of liquid from
the container,
into liquid inlet 70 of tube portion 66, and thus also into liquid conduit 56.
As will be
appreciated from the description of Figs. 3A-3C below, the pressure just
downstream of
fluid outlet apparatus 20 is atmospheric, thereby providing a required
pressure drop, and
thus enabling the described liquid outflow to occur. Preferably, levers 72 are
linked by any
suitable means (not shown), so as to be operable sirnultaneously.
Reference is now made to Figs. 3A, 3B and 3C, in which the fluid delivery head
14
(Fig. 3A) and portions of the valve mechanisms thereof (Figs. 3B and 3C) are
shown in
detail. As described above, delivery head 14 has a liquid entry port 16, a gas
entry port 18,
and fluid outlet apparatus 20, via which a gas and liquid mist outflow is
provided, at near
sonic velocity.
It will be appreciated by persons skilled in the art that the construction of
the fluid
delivery head 14, as described below in conjunction with Figs. 3A-3C, is by
way of example
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only, and other suitable types of connections and valves may be used, also in
accordance
with the invention.
Fluid delivery head 14 includes a valve assembly, referenced generally 79,
which
facilitates passage of liquid and gas, respectively, from liquid entry port 16
and gas entry
port 18, to a gas and liquid combining nozzle member 108, described below.
Valve
construction 79 includes a body 80 which has formed, in a rear portion
thereof, liquid entry
port 16 and gas entry port 18. Body 80 further includes laterally positioned
liquid and gas
valve chambers, respectively referenced 82 and 84, and which are separated
from each
other, but which are connected with respective entry ports 16 and 18 via a
first liquid supply
bore 86 and a first gas supply bore 88. Valve chambers 82 and 84 are also
connected, via
respective second liquid supply bore 90 and second gas supply bore 92, to a
front portion
of body 80, referenced generally 94.
Front body portion 94 has formed thereon an inner recessed portion 96, and an
outer recessed portion 98, which surrounds inner recessed portion. Inner
recessed portion
96 communicates with second liquid supply bore 90, and outer recessed portion
communicates with second gas supply bore 92. An inner nozzle member 100 is
seated
within inner recessed portion 96 so as to be contiguous with second liquid
supply bore 90,
and terminates in a narrow bore front nozzle opening 102, through which a
narrow jet of
liquid is emitted. A cylindrical, gas-liquid combining member 108 is mounted
within outer
recessed portion 98 concentric with surrounding inner nozzle member 100.
Combining member 108 has a front portion, indicated generally 110, which is
formed
so as to converge towards an opening 112, which, as seen, is generally coaxial
with nozzle
opening 102 of inner nozzle member 100. Combining member 108 is configured so
as to
cause a central conversion of the gas throughflow in head 14 towards the
liquid jet
emerging from front nozzle opening 102. Accordingly, as the liquid jet and the
gas flow
converge upon each other, they become combined into a single gas and liquid
jet in the
front portion 110 of combining member 108.
Each of valve chambers 82 and 84 contains a valve mechanism, having a
construction typically as described below. As these typical valve mechanisms
are identical
to each other, they are both indicated by reference numeral 120, and the
components
common to both valve mechanisms are indicated by similar reference numerals.
Each valve
mechanism 120 has a cylindrical seating member 122, in which is located an
inner valve
plate 124.
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Referring now also to Figs. 3B and 3C, it is seen that, in the present
example, valve
plate 124 has a generally conical, outwardly tapering valve opening 126 in
which is seated
a conical valve element 128. Valve element 128 is maintained, in the absence
of any
opposing forces, in a retracted, sealed position within opening 126, as shown
in Fig. 3C, by
means of resilient tension means 130, such as a tension spring. Each thumb
controlled
fever 72 (Figs. 1 and 3A) has a transversely extencling threaded bore 134
(Fig. 3A) formed
therein. As seen in Fig. 3A, a screw element 136 e;Ktends through bore 134 and
terminates
in a thickened end portion 138. A nut member 140 is connected to end portion
138, and is
arranged for free rotation relative thereto, about the longitudinal axis 142
of screw element
136. Nut member 140 is seated in a piston-type casing 144 which is arranged
for axial
movement along inward-facing tracks 146 formed in seating member 122.
In the position shown in Fig. 3C, it is seen that valve opening 126 is closed
by valve
element 128. Rotation of lever 72 in a predetermined direction is operative to
cause an
inward, linear translation of screw element 136. As nut member 140 is free to
rotate about
axis 142, it does not sustain any rotational moment, and is merely depressed
inward by
screw element 136. This inward movement causes a corresponding inward movement
of
casing 144 along tracks 146, which acts on a rear extension 148 of valve
element 128 so as
to depress it inwards, as shown by arrows 149 in Fig. 3B, thereby to cause a
partial opening
of valve opening 126, and enabling a throughflow of gas or liquid.
Valve plate 124 has a plurality of first radial bores 150 formed in a rear
portion
thereof, which communicate with the interior of valve seating member 122.
Valve seating
member 122 has one or more second radial bores 152, which communicate with an
exterior
recess 154.
The recesses 154 and the second liquid and gas supply bores 90 and 92 are
formed
such that opening of valve openings 126 enables respective throughflows of
liquid and gas
along flow paths constituted by valve openings 126, first radial bores 150 of
valve plate 124,
second radial bores 152 of valve seating member 122, recesses 154, and either
of the
supply bores 90 or 92.
As described above, the gas is pressurized, and is supplied at a steady
pressure of
2-3 atm. While there may be a minimal head loss during flow through delivery
head 14, the
delivery head 14 is constructed so as to minimize such head loss, and so as to
ensure that
the fluid pressure remains in excess of 2 atm, until the point where the
combined jet
emerges through opening 112 of combining member 108, into the atmosphere.
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It will be appreciated by persons skilled in the art that, as the combined
fluid jet
emerges into atmospheric pressure, it undergoes an instantaneous pressure
drop, from 2
atm or more, to 1 atm. A sudden pressure drop of this magnitude results in a
velocity of the
combined jet at the point of emergence into the atmosphere that approximates
the velocity
of sound , namely, 330 m/s., and in the production of a shock wave in the jet.
The effect of
the shock wave is to atomize the liquid fraction of the combined jet into
microscopic water
droplets, such that there is obtained a jet consisting of a liquid mist
suspended in a gas jet,
having a near sonic velocity.
It has been found by the inventor that, when the delivery head 14 is held
close to
tissue being cleansed, typically at a distance of up to about 10 cm, the
microscopic liquid
droplets bombard it and all contaminants thereon, thereby to forcibly remove
them from the
tissue, thereby cleansing it.
The wetting of the contaminants in this way, namely, by microscopic droplets,
cause
a substantial increase in their aerodynamic resistance, such that the force of
the
bombardment by the combined fluid jet is able to separate them from the tissue
surface and
carry them away in the droplet stream. The increase in the aerodynamic
resistance of the
particles is facilitated by the wetting by droplets, on the one hand, and by
the absence of a
liquid stream on the tissue surface with a stable boundary layer, on the other
hand.
Accordingly, as none of the contaminant matter is protected by a stable
boundary layer of a
liquid stream, it is all exposed to removal by the gas-liquid droplet stream.
Reference is now made to Fig. 4, which illustrates a fluid delivery head,
referenced
generally 200, and to Fig. 5, which illustrates in detail the nozzle 202 of
the fluid delivery
head 200, constructed in accordance with an alternative embodiment of the
invention.
Delivery head 200 is similar to delivery head 14, shown and described above in
conjunction
with Figs. 1 and 3A, and is thus not described again herein except with regard
to
differences between delivery head 200 and delivery head 14. Accordingly,
components of
delivery head 200 seen in either of Figs. 1 or 3A, and having counterpart
components
therein, are denoted in Fig. 5 by similar reference numerals but with the
addition of a prime
(') notation.
Referring again to Fig. 5, delivery head 200 is characterized by having a
nozzle,
referenced generally 202, which incorporates in a unitary member a rear, gas-
liquid
combining portion 204, and a front, suction portion 206. Nozzle 202 generally
has an
hourglass configuration, such that rear portion 204 and front portion 206
taper towards a
narrow waist or transition portion 208. Inner nozzle member 100' is formed so
as to protrude
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slightly through transition portion 208 and has a corresponding, slightly
narrowed waist
portion 210 whose diameter increases, as seen, as it protrudes into suction
portion 206.
As a gas stream, shown by arrow 212, at super-atmospheric pressure, enters the
narrowing annular passageway 214 defined between inner nozzle member 100' and
nozzle
202, it accelerates from a sub-sonic velocity, at the entrance 216 of the
constricting
passageway, to sonic velocity, at a location 218 part-way along the
passageway, to
supersonic velocity, at a location 219 as the constricted passageway abruptly
terminates
due to a step formed by front edge 220 of inner nozzle member 100'. As the gas
flow
emerges into the widening front nozzle portion 2!06 from transition zone 208,
it expands
rapidly. The expansion wave thus generated undergoes a considerable pressure
drop, to at
least subatmospheric pressure, thereby also giving rise to a conical
rarefaction zone 221
along the inner surtace 222 of front nozzle portion :206.
An accelerating liquid stream emerging through passing through nozzle opening
102' emerges into the supersonic gas stream, and, due to the sharp pressure
drop
experienced, substantially as described above in conjunction with Figs. 1-3C,
atomizes into
microscopic droplets which are then swept into thE~ gas stream, so as to form
a combined
gas-liquid mist stream.
When the fluid delivery head 200 is held close to tissue 224 contaminated with
various pollutant particles, at a distance of, for example, 3-8 mm, these
particles are
exposed to the described subatmospheric pressure obtaining in the nozzle
cavity. In
addition to the microscopic liquid droplet bombardment as described above in
conjunction
with Figs. 1-3C, therefore, the pollutant particles are also exposed to a
suction force as the
nozzle is brought close to the tissue being cleansed, which helps to loosen
the particles
from the tissue, prior to being carried away in the gas-liquid mist.
It will be appreciated by persons skilled in the art the scope of the present
invention
is not limited by what has been particularly shown .and described above.
Rather, the scope
of the invention is limited solely by the claims, which follow.
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