Surgery – Means for introducing or removing material from body for... – Gas application
Reexamination Certificate
1998-11-18
2001-09-04
Nguyen, Anhtuan T. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Gas application
C604S035000, C604S290000
Reexamination Certificate
active
06283936
ABSTRACT:
FIELD 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 like, 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. More 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 sufficient 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 U.S. Pat. Nos. 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.
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 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 gas-liquid outflow downstream of the fluid outlet, 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 flow downstream of the fluid outlet 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 fluid outlet apparatus also includes apparatus for applying a suction force to the tissue being cleansed.
Additionally in accordance with a preferred 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 interior 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 tapering 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.
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 connection to a pressurized oxygen source, 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, ther
Fay Sharpe Fagan Minnich & McKee LLP
Nguyen Anhtuan T.
Tav-Tech Ltd.
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