AU2007203640B2 - Articulating ionizable gas coagulator - Google Patents

Description

S&F Ref: 525654D2 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address Sherwood Services AG, of c/- US Surgical Corp - Legal of Applicant: Dept (Patent Gen Counsel) 150 Glover Avenue, Norwalk, Connecticut, 06856, United States of America Actual Inventor(s): Robert C Platt Address for Service: Spruson & Ferguson St Martins Tower Level 35 3 1 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: Articulating ionizable gas coagulator The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(896728_ I) ARTICULATING IONIZABLE GAS COAGULATOR The present disclosure relates to gas-enhanced electrosurgical instruments for coagulating tissue. More particularly, the present disclosure relates to an articulating, gas-enhanced electrosurgical apparatus for coagulating tissue. Background of Related Art Over the last several decades, more and more surgeons are abandoning traditional open methods of gaining access to vital organs and body cavities in favor of endoscopes and endoscopic instruments which access organs through small puncture-like incisions. Endoscopic instruments are inserted into the patient through a cannula, or port, that has been made with a trocar. Typical sizes for cannulas range from three millimeters to twelve millimeters. Smaller cannulas are usually preferred, and this presents a design challenge to instrument manufacturers who must find ways to make surgical instruments that fit through the cannulas and operate in a safe and effective manner. I5 Endoscopic instruments for arresting blood loss and coagulating tissue are well known in the art. For example, several prior art instruments employ thermal coagulation (heated probes) to arrest bleeding. However, due to space limitations 1 surgeons can have d;f(;,ulty manipulating the instrument to coagulate, desiccate, fulgurate and/or cut tissue. Moreover, if the probe comes into close contact with the tissue, the probe may adhere to the eschar during probe removal possibly causing repeat bleeding. Other instruments direct high frequency electric current through the 6 tissue to stop the bleeding. Again, eschar adherence may also be a problem with these instruments. In both types of instruments, the depth of the coagulation is difficult to control. U.S. Patent No. 5,207,675 to Canady attempts to resolve certain of the above-noted problems with respect to the prior art by providing a tube-like *0 coagulation instrument in which an ionizable gas is forced through the instrument and ionized by an electrode in the region between the distal end of the instrument and the bleeding tissue. The electrode, then, does not contact the tissue. U.S. Patent No. 5,720,745 to Farin et al. discloses a coagulation instrument which extends through a working channel of an endoscope and includes 16 an electrode for ionizing a stream of ionizable gas exiting the distal end of the instrument at a rate of less than about 1 liter/minute. As explained in detail in the Farin et al. specification, the purpose of discharging the gas at a very low flow rate is to effectively cloud the tissue area and create an ionizable gas "atmosphere" to gently coagulate the tissue Using these instruments to treat certain more tubular sites, e.g., the esophagus and/or colon, is often difficult, impractical and time consuming. For 2 example, these longitudinally oriented instruments fire the ionised gas and the RF energy in an axial direction from their respective distal ends which, in the case of tubular tissue, would be parallel to the bleeding tissue. Thus, manipulating these instruments to focus the energy transversely or off-axis at the bleeding tissue may be very difficult. 5 Thus, a need exists for the development of a new and effective instrument for treating certain more tubular tissue. Object of the Invention It is an object of the present invention to overcome or ameliorate some of the disadvantages of the prior art, or at least to provide a useful alternative. 10 Summary of the Invention There is disclosed herein an electrosurgical apparatus for coagulating tissue having a: an elongated flexible tube having a proximal end and a distal end and defining a longitudinal axis; is a wire connected to the distal end of the tube, the wire being movable from a first generally relaxed position wherein the tube is disposed in a generally rectilinear fashion relative to the tissue to a second retracted position wherein the distal end of the tube directs pressurized ionizable gas flowing through the tube at an angle with respect to the longitudinal axis; 20 an active electrode for ionizing pressurized ionizable gas; and a corona electrode disposed proximate the active electrode for forming a corona around the active electrode. There is disclosed herein an electrosurgical apparatus for coagulating tissue, comprising: 25 an elongated flexible tube having a proximal end and a distal end and defining a longitudinal axis, the tube including a sleeve being selectively extendable therethrough; the sleeve including a distal end being movable from a first position wherein the distal end is disposed in a generally rectilinear fashion relative to the tissue to a second position wherein the distal end directs pressurised ionizable gas flowing through the 30 sleeve at an angle u' with respect to the longitudinal axis wherein the angle of the distal end of the sleeve relative to the longitudinal axis progressively changes proportionally to the distance the distal end of the sleeve extends from the tube; and 3 at least one electrode mounted proximal to the sleeve distal end for ionizing pressUrised ionizable gas. There is also disclosed herein an electrosurgical apparatus for coagulating tissue, comprising an elongated flexible tube having a proximal end and a distal end and defining 5 a longitudinal axis; a wire connected to the distal end of the tube, the wire being movable from a first generally relaxed position wherein the tube is disposed in a generally rectilinear fashion relative to the tissue to a second retracted position wherein the distal end of the tube directs pressurised ionizable gas flowing through the tube at an angle with respect to the longitudinal axis; and at least one electrode mounted proximate to the tube 1o for ionizing pressurised ionizable gas. This is also disclosed herein an electrosurgical apparatus for coagulating tissue, comprising an elongated flexible tube having a proximal end and a distal end and defining a longitudinal axis, the tube including a bendable sleeve which is configured such that the angle of a portion of the bendable sleeve relative to the longitudinal axis progressively is changes proportionally to the distance that the portion of the sleeve extends from the tube; the distal end of the tube being movable from a first position wherein the distal end is disposed in a generally rectilinear fashion relative to the tissue to a second position wherein the distal end directs pressurised ionizable gas flowing through the tube at an angle a with respect to the longitudinal axis; and at least one electrode mounted 20 proximate to the tube for ionizing pressurised ionizable gas. 4 BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a front, perspective view of an electrosurgical instrument shown extending through a working channel of a flexible endoscope; Fig. 2A is an enlarged, side sectional view of one embodiment of the present disclosure showing a hollow shape memory sleeve in retracted position within a catheter; Fig. 2B is an enlarged view of the hollow shape memory sleeve shown in austenite configuration; Fig. 3 is an enlarged, side sectional view of the shape memory sleeve to of Figs. 2A and 2B shown extending and articulating from the catheter to direct ionized gas at the tissue; Fig. 4 is an enlarged, side sectional view of another embodiment of the present disclosure showing a pull wire/return electrode affixed at the distal end of a flexible catheter; Is Fig. 5 is an enlarged, side sectional view of the embodiment of Fig. 4 showing the wire being drawn to articulate the flexible catheter and direct ionized gas at the tissue; 5 Fig. 6 is an enlarged, side sectional view of another embodiment of the present disclosure showing a ring corona electrode and a dielectric sleeve seated within a flexible catheter and a pull wire/return electrode affixed at the distal end of the flexible catheter; Fig. 7 is a cross sectional view of the Fig. 6 embodiment taken along line 7-7; and Fig. 8 is an enlarged, side sectional view of the embodiment of Fig. 6 showing the pull wire/return electrode being drawn to articulate the flexible catheter and direct ionized gas at the tissue. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to Fig. 1, an articulating tissue coagulator generally identified by reference numeral 10 is shown extending through a working channel of an endoscope 12. Preferably, the coagulator 10 can be employed with a variety of different endoscopes such as those manufactured by Olympus, Pentax and Fujinon. As such, only the basic operating features of the endoscope 12 which work in combination with the present disclosure need to be described herein. For example, endoscope 12 includes a handpiece 26 having a proximal end 27 and a distal end 29. In the drawings and in the description which follows, the term "proximal", as is traditional, will refer to the end of the apparatus which is closer to the user, while the term "distal" will refer to the end which is further from the user. 6 Preferably, the proximal end of the coagulator 10 is mechanically coupled to a supply 18 of pressurized ionizable gas, e.g., inert gas, by way of hose 20 and electrically coupled to an electrosurgical generator 22 by way of cable 24 to supply a source of electrosurgical energy, e.g., high frequency coagulation current. 5 It is envisioned that the electrosurgical generator 22 selectively controls the amount of electrosurgical energy transmitted to an electrode during a surgical procedure. It is also envisioned that the supply of pressurized ionizable gas selectively controls the rate of flow of gas. A pressure regulator, designated by reference numeral 21, is preferably provided to regulate the fluid pressure. 10 As shown in Fig. 1, a long, flexible tubular member 13 having one or more of working channels 14 located therein is mechanically coupled to the distal end 29 of the handpiece 26. Preferably, at least one of the working channels 14 is sufficiently dimensioned to receive the coagulator 10 of the present disclosure. Other working channels 14 can be utilized to receive other surgical instruments and Is accessories such as graspers and biopsy forceps. Turning now to Figs. 1, 2A, 2B and 3, one preferred embodiment of the coagulator 10 is shown therein and includes an elongated, generally flexible catheter or tube 30 having a proximal end 32 which extends through a working channel 14 of the endoscope 12 and a distal end 34 which projects outwardly from the distal end Z10 15 of tube 13. Ionizable gas 28, e.g., argon, is supplied to the proximal end 32 of the coagulator 10 by a gas conduit (not shown) located inside tube 13. Preferably, gas 7 28 is supplied from source 18 to the coagulator 10 at a selectable, predetermined flow rate and flows generally within the tube 30 in the direction of the arrow towards the distal end 34 of tube 30. Advantageously, the flow rate of the gas 28 is selectively adjustable and can easily be regulated depending upon a particular 6" purpose or a particular surgical condition. Electrode 48 produces an RF electric field, which ionizes the gas 28 in the region between the electrode and the tissue 50. Electrode 48 is connected by way of an electrical conduit (not shown) disposed within tubes 30 and 13 which is ultimately connected to electrosurgical generator 22. Preferably, the electrode 48 is 10 ring or pin-type and is spaced from the distal end 34 such that the electrode 48 cannot come into contact with the tissue 50 during the surgical procedure. A return electrode or pad 17 is positioned on the patient and is electrically coupled to the electrosurgical generator 22 to provide a return path for the electrosurgical current. Preferably, a stream of gas plasma 46 conducts the current to the Is tissue 50 while effectively scattering blood away from the treatment site allowing the tissue 50 to readily coagulate and arrest bleeding. A gas plasma 46 is an ionized gas that is used in surgical procedures to conduct electrosurgical energy to a patient without electrode contact by providing a pathway of low electrical resistance. The electrosurgical energy will follow this path and can therefore be used to coagulate, to desiccate, or fulgurate blood or tissue 50 of the patient. One of the advantages of this procedure is that no physical contact is required between an electrode 48 and 8 the tissue 50 being treated, One advantage of having a directed flow of gas 28 is that the plasma arc can be accurately focused and directed by the flow. As best seen in Figs. 2A, 28 and 3, one approach for manipulating and/or directing the plasma/ionized gas 46 emitting from the distal end 34 of the tube 30 is to implant a hollow sleeve 40 having shape memory characteristics within the distal end 34 of the tube 30. Preferably, as the sleeve 40 is extended from the distal end 34 of the tube 30, the sleeve 40 flexes and directs the ionized gas 46 towards the tissue 50. More particularly, shape memory alloys (SMAs) are a family of alloys having anthropomorphic qualities of memory and trainability and are particularly well suited for use with medical instruments. SMAs have been applied to such items as actuators for control systems, steerable catheters and clamps. One of the most common SMAs is Nitinol which can retain shape memories for two different physical configurations and changes shape as a function of temperature. Recently, other SMAs have been developed based on copper, zinc and aluminum and have similar shape memory retaining features. SMAs undergo a crystalline phase transition upon applied temperature and/or stress variations. A particularly useful attribute of SMAs is that after it is deformed by temperature/stress, it can completely recover its original shape on 2p being returned to the original temperature. The ability of an alloy to possess shape memory is a result of the fact that the alloy undergoes a reversible transformation 9 from an austenite state to a martensite state with a change ;n temperature (or stress induced condition). This transformation is referred to as a thermoelastic martensite transformation. Under normal conditions, the thermoelastic martensite transformation 15 occurs over a temperature range which varies with the composition of the alloy, itself, and the type of thermal-mechanical processing by which it was manufactured. In other words, the temperature at which a shape is "memorized" by an SMA is a function of the temperature at which the martensite and austenite crystals form in that particular alloy. For example, Nitinol alloys can be fabricated so that the shape 1o memory effect will occur over a wide range of temperatures, e.g., -270* to +1000 Celsius. Many SMAs are also known to display stress-induced martensite (SIM) which occurs when the alloy is deformed from its original austenite state to a martensite state by subjecting the alloy to a stress condition. For example and with Kf respect to Figs. 2A, 2B and 3 of the present disclosure, hollow sleeve 40 is generally bent or L-shaped when disposed in its original or austenite state (see Fig. 28). When sleeve 40 is inserted into the tube 30, sleeve 40 is deformed, i.e., straightened, into a stress-induced martensite state enabling the user to more easily insert through the endoscope navigate the tube 30 through tight body cavities and XP passageways to access damaged tissue 50. 10 As seen best in Fig. 3, after insertion of the tube 30 into the body cavity/passageway, the user can easily direct the ionized gas 46 flowing through the tube 30 transversely (off-axis) at the tissue 50 by extending the sleeve 40 distally which causes the extended portion of the sleeve 40 to revert back to its .5 original/austenite state (it is assumed that the temperature of use of the alloy allows spontaneous reversion when stress is removed). The user can also control the angle s, of the ionized gas 46 being directed at the tissue 50 by controlling the distance "X" that the sleeve 40 extends from the tube 30. Preferably, angle s, and distance "X" are directly related, i.e., as distance "X" increases angle s, increases. '0 It is envisioned that by empowering the user to articulate, i.e., bend, the distal end 41 of the sleeve 40 at various angles s, will enable the operator to more effectively coagulate bleeding tissue 50 with more longitudinal-type lesions, i.e., tissue lesions which run parallel to the axial direction of endoscope 12, and without causing collateral tissue damage. It is also envisioned that by adjusting the L5 angle s, of the distal end 41 of the sleeve 40, the angle with respect to the tissue surface or longitudinal axis of the tube at which the ionized gas 46 impinges can be selectively controlled. Figs. 4 and 5 show another embodiment of an articulating coagulator 110 which includes an elongated tube 130 having a proximal end 132 and a distal ZO end 134. Preferably, tube 130 is flexible at or proximate the distal end 134 of tube 130. Ionizable gas 28 is supplied to the proximal end 132 of the coagulator 110 at a selectable, predetermined flow rate and flows generally within the tube 130 in the 11 direction of the arrow towards the distal end 134 of tube 130. Advantageously, the flow rate of the gas 28 is selectively adjustable and can easily be regulated depending upon a particular purpose or a particular surgical condition. Much in the same manner as described with respect to Figs. 2A, 28 and 3, electrode 48 g discharges an electrosurgical current which ionizes gas 28 prior to gas 28 emission. Coagulator 110 also includes a pull wire 160 which is connected at one end proximate the distal end 134 of tube 130 such that retraction of wire 160 flexes tube 130. Preferably, wire 160 is disposed within the proximal end 132 of tube 130 and exits a port 136 disposed within tube 130 to attach to tube 130 at a point IV proximate distal end 134. Wre 160 is movable from a first generally relaxed position wherein tube 30 is disposed in a generally rectilinear fashion relative to tissue 50 (see Fig. 4) to a second retracted or tensed position wherein the distal end 134 of tube 130 flexes towards tissue 50 (see Fig. 5). The user can easily direct the ionized gas 46 flowing through the tube 130 transversely at tissue 50 by controlling is' the tensile force applied to wire 160 which, in turn, flexes the distal end 134 of tube 130 to a desired angle s, Empowering the user to articulate, i.e., flex, the distal end 134 of the tube 130 at various angles s, will enable the operator to more effectively target bleeding tissue 50 without causing collateral tissue damage. In some cases it may be preferable to utilize wire 160 as a return electrode and couple wire 160 to electrosurgical generator 22. In this case, the portion of wire 160 disposed within tube 130 is preferably insulated to avoid unintentional ignition and ionization of gas 28. 12 Figs. 6-8 show another embodiment which includes an articulating coagulator 210 having an elongated tube 230 with proximal and distal ends 232 and 234, respectively. Preferably, tube 230 is flexible at or proximate the distal end 234. Coagulator 210 contains many of the same components and features of the Figs. 4 and 5 embodiment with the exception that a "corona ring" electrode is located at the distal end 234 of tube 230 and is used to initiate ionization of gas 28. A "corona" is a type of discharge which forms around an active electrode and can be used to increase the reliability of plasma ignition. Coronas are low current discharges and consume very little power and, therefore, do not affect the overall power delivered to the tissue. Coronas typically occur in highly non uniform electric fields which are commonly generated between electrodes of greatly differing sizes. A corona electrode is typically located proximate the active electrode 48 and is electrically connected to the return potential of the electrosurgical i generator 22. For example and with respect to the Fig. 6 embodiment, a ring corona electrode 275 is disposed at the distal end 234 of tube 230 in co-axial alignment with the active electrode 48. As seen best in Fig. 7. a dielectric or insulating sleeve 270 is disposed between the corona electrode 275 and active electrode 48 to prevent arcing 13 between electrodes 270 and 48. Preferably, dielectric sleeve 270 is made from a ceramic material or other high temperature resistant material. When the electrosurgical generator 22 is activated, a non-uniform electric field is generated between corona electrode 275 and active electrode 48 and .6 a corona forms around active electrode 48 which aids in igniting gas 28 to produce gas plasma 46. As mentioned above, coagulator 210 also includes a wire 260 which is connected at one end proximate the distal end 234 of tube 230 such that retraction of the wire 260 flexes tube 230. Preferably, wire 260 is also connected to corona *~ electrode 275 and performs a dual function: 1) to electrically connect corona electrode 275 to electrosurgical generator 22; and 2) to empower the user with the ability to selectively articulate the distal end 234 of tube 230 at varying angles s, to effectively coagulate bleeding tissue 50 in a manner similar to the manner described with respect to the Fig. 4 embodiment. More particularly and as best seen in Fig. 8, the user can easily direct gas plasma 46 exiting tube 230 transversely at tissue 50 by controlling the tensile force applied to wire 260 which, in turn, articulates distal end 234 to a desired angle S, and enables the user to more effectively coagulate or arrest bleeding tissue 50 without causing collateral tissue damage. 14 From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that not only can the coagulator 10, 110 and 210 of the present disclosure be used to arrest bleeding tissue, but the present disclosure can also be employed for desiccating the surface tissue, eradicating 15 cysts, forming eschars on tumors or thermically marking tissue. Those skilled in the art will also appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the present disclosure. In some cases it may be preferable to use various combinations of the component parts shown with respect to each of the embodiments described herein. 10 For example, it may be preferable to combine a SMA (or a stress-induced martensite) with a wire to articulate the distal end of the tube. In another case it may be preferable to use a ring-like corona return electrode with an SMA to induce plasma ignition. In some cases it may be preferable to employ an electrode control mechanism to allow a user to selectively adjust the amount of current flowing through the electrodes during surgical conditions. Moreover, even though it may be preferable to use argon as the ionizable gas for promulgating coagulation of the tissue, in some cases it may be preferably to use another ionizable gas to effect the same or different result. There have been described and illustrated herein several 2o embodiments of a coagulator for arresting bleeding and performing other surgical 15 procedures. While paitcular embodiments of the disclosure have been described, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplications of preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto. 16

Claims (10)

1. An electrosurgical apparatus for coagulating tissue having a: an elongated flexible tube having a proximal end and a distal end and defining a longitudinal axis; s a wire connected to the distal end of the tube, the wire being movable from a first generally relaxed position wherein the tube is disposed in a generally rectilinear fashion relative to the tissue to a second retracted position wherein the distal end of the tube directs pressurized ionizable gas flowing through the tube at an angle with respect to the longitudinal axis; I an active electrode for ionizing pressurized ionizable gas; and a corona electrode disposed proximate the active electrode for forming a corona around the active electrode.

2. An electrosurgical apparatus according to claim 1, further comprising a dielectric sleeve disposed between the active electrode and the corona electrode. 5

3. An electrosurgical apparatus according to claim 2, wherein the dielectric sleeve is ceramic.

4. An electrosurgical apparatus according to claim 1, further comprising a regulator for regulating gas flow through the tube.

5. An electrosurgical apparatus according to claim 1, further comprising a 20 supply of pressurized gas.

6. An electrosurgical apparatus according to claim 5, wherein the pressurized gas is argon.

7. An electrosurgical apparatus according to claim 1, wherein the angle relative to the longitudinal axis progressively changes proportionally to the amount of 25 tension placed on the wire.

8. An electrosurgical apparatus according to claim 1, wherein the wire acts as a return electrode.

9. An electrosurgical apparatus according to claim 8, wherein a portion of the wire is disposed within the elongated flexible tube, and is insulated to prevent 30 unintentional ignition and ionization of the gas. 17

10. An electrosurgical apparatus according to claim 1, wherein the wire is adapted to connect the corona electrode to an electrosurgical generator. Dated 3 August, 2007 Sherwood Services AG 5 Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON l 8