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WO1997003619A2 - Instrument electro-chirurgical coaxial - Google Patents

Instrument electro-chirurgical coaxial Download PDF

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Publication number
WO1997003619A2
WO1997003619A2 PCT/US1996/012065 US9612065W WO9703619A2 WO 1997003619 A2 WO1997003619 A2 WO 1997003619A2 US 9612065 W US9612065 W US 9612065W WO 9703619 A2 WO9703619 A2 WO 9703619A2
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WO
WIPO (PCT)
Prior art keywords
tissue
electrode
end portion
outer electrode
distal
Prior art date
Application number
PCT/US1996/012065
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English (en)
Other versions
WO1997003619A3 (fr
Inventor
Gary Long
Original Assignee
Laser Centers Of America
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Laser Centers Of America filed Critical Laser Centers Of America
Priority to AU65068/96A priority Critical patent/AU6506896A/en
Publication of WO1997003619A2 publication Critical patent/WO1997003619A2/fr
Publication of WO1997003619A3 publication Critical patent/WO1997003619A3/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14—Probes or electrodes therefor
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14—Probes or electrodes therefor
    • A61B18/1402—Probes for open surgery

Definitions

  • This invention relates to an improved electrosurgical instrument capable of performing incisions and coagulating and cauterizing functions, and more particularly to a coaxial electrosurgical instrument which performs like and can be used as easily as a monopolar surgical instrument but which eliminates current flow through the patient like a bipolar surgical instrument and cuts through tissue at controlled rates which efficiently minimize related bleeding.
  • electrosurgical instruments In recent times, the use of electrosurgical instruments to perform precise surgery has become widespread, mainly because it offers significant advantages over traditional scalpel surgery. For many surgical procedures, e.g., open heart surgery and laparscopic procedures, electrosurgery results in significantly less patient trauma. In neurosurgical procedures, because of the very sensitive tissue around the surgical site and the need to immediately limit bleeding, the facility to perform incisions and coagulations with a single electrosurgical instrument is highly advantageous. Similarly, in transurethral surgery, where the goal is to safely remove unwanted or diseased tissue from a prostrate gland, the operation is best done with an electrosurgical instrument because the surgeon has to operate through a relatively narrow bore resectoscope. In any such surgical procedure, while speed in precisely incising tissue is important it is equally important to promptly and effectively cauterize incised blood-carrying vessels to avoid obscuration of the surgical site.
  • Electrosurgical instruments can dissect tissue while at the same time reducing the amount of blood loss by permitting quick coagulation of the dissected tissue. Cutting occurs when the current density is high enough to explode the tissue cells near the electrode, and the same instrument may have a portion usable to either seal an incised vessel or to accelerate the coagulation process.
  • a damped current waveform comprising short bursts of current rather than a continuous current, may be provided to the tissue. This causes local cellular dehydration because of the smaller amount of electrical current and power delivered to the tissue. It allows the surgeon to obtain hemostasis, allowing him to destroy tissue masses, or to cause selective desiccation of tissue. For a blended operation the surgeon may apply a current having a waveform as indicated at the right portion of Figure 1.
  • providing continuous high amplitude current via a thin electrode can generate a pure cut, and applying a damped waveform can generate a blended cut in which there is incision of tissue as well as coagulation of any blood leakage nearby.
  • a damped waveform can generate a blended cut in which there is incision of tissue as well as coagulation of any blood leakage nearby.
  • a monopolar instrument is one in which the electrical current flows from the active electrode, which may be shaped as a blade, a hook, or a straight ended wire, to an electrical "ground".
  • a grounding pad is typically applied to the thigh, back or some other spot on the patient's body where contact may be made with a relatively large surface area.
  • the surface area of one of the two electrodes is deliberately made significantly larger than that of the other. This is done so that the current density is much greater at the electrode having the smallest surface area when in contact with the patient's tissue. In such applications, the electrode with the smaller surface area is referred to as the
  • the frequency of the electrical voltage used for electrosurgery of any kind is typically much higher than the conventional mains frequency of 60 Hz, often in the range 400,000 Hz to 3,000,000 Hz, a range commonly referred to as "radiofrequency. Radiofrequency is generally considered too high to stimulate muscular tissue and, therefore, is believed to be safe to the patient. However, because the electrical current must flow through a significant portion of the patient's body, the surgeon and staff are at some risk of being shocked because of capacitive coupling with the patient. 'Also, the high voltage/high frequency generator and the wire leading therefrom to the active electrode, can act as an electrical noise generator and may adversely affect sensitive instrumentation.
  • a bipolar instrument In light of the above-described problems with a monopolar instrument, a bipolar instrument is sometimes used. It requires no grounding pad to be applied to the patient, but instead employs two electrodes which mechanically oppose each other like the two halves of a surgical forceps. The instrument is used to squeeze tissue between the two electrodes as a current passes between them to cause coagulation. Thus, a bipolar surgical instrument normally is used only when coagulation is desired and when current flowing through the patient is clearly undesirable. The bipolar instrument is not used to dissect tissue in most cases because it does not permit the surgeon to do so with precision.
  • Reference to Figure 3 shows various types of monopolar active electrode tip shapes as well as the general tip end structure of a bipolar instrument .
  • Figure 4 illustrates the general overall configuration of a bipolar instrument.
  • Figures 5 (A) -5 (C) schematically indicate the typical distributions of electrical lines of force and equipotential lines normal thereto (as broken lines) : for a monopolar instrument having a single electrode contacting the tissue to be operated on; for a bipolar instrument with two electrodes between which current flows through the patient's tissue, and for a coaxial surgical instrument (CSI) as in this invention in which there is a single electrode coaxially surrounded by an outer electrode with the entire operative electrical field highly localized and contained therebetween.
  • CSI coaxial surgical instrument
  • the present invention relates to a particularly advantageous form of a coaxial surgical instrument and has the general form illustrated in Figure 6 and explained more fully hereinbelow.
  • a coaxial electrosurgical instrument which comprises an elongate, tubular, outer electrode covered with an insulating sleeve which leaves a distal end portion of the outer electrode uninsulated.
  • An elongate inner electrode is located coaxially within the outer electrode and is electrically insulated therefrom.
  • a distal uninsulated end portion of the inner electrode extends to a predetermined length from the distal uninsulated end portion of the outer electrode.
  • the distal end portion of the outer electrode preferably has a transverse end surface inclined at a first angle relative to a common axis of the inner and outer electrodes.
  • the distal uninsulated end portion of the inner electrode has a distal end bent sideways and has a smoothly rounded bulbous tip.
  • a method which includes the steps of providing an elongate tubular outer electrode covered with an insulating sleeve which leaves a distal end portion of the outer electrode uninsulated, and also providing an elongate inner electrode located coaxially within the outer electrode.
  • the two coaxial electrodes are electrically insulated from each other and a distal uninsulated end portion of the inner electrode extends to a predetermined length from the distal uninsulated end portion of the outer electrode, is angled, and has a rounded bulbous end. This enables the user to make simultaneous electrical contact by rounded bulbous end of the distal uninsulated end portion of the inner and the distal uninsulated end portion of the outer electrode with the tissue being operated on.
  • the related method of using such a surgical instrument includes the steps of providing an alternating electrical voltage difference at a controlled frequency between the inner and outer electrodes and applying the rounded bulbous end at the distal uninsulated end portion of the inner electrode and the distal uninsulated end portion of the outer electrode simultaneously to the selected tissue. This causes a high frequency, high density, current to flow through only that portion of the contacted tissue which lies between the applied inner and outer electrodes.
  • Figure 1 is a graphical plot showing electrical current waveforms suitable for use during cutting, coagulation, and blended surgical operation with an electrosurgical instrument of any kind.
  • Figure 2 shows in schematic form how differently shaped monopolar electrosurgical instrument tips may be used to perform a pure cut, a blended cut, desiccation of a tissue, or fulguration.
  • Figure 3 shows exemplary active electrode tip shapes for monopolar and bipolar electrosurgical instruments of known type.
  • Figure 4 is a side view of a bipolar electrosurgical instrument of known type.
  • Figures 5 (A) -5(C) present schematic views of the distributions of electric lines of force and equipotential lines for monopolar, bipolar, and coaxial surgical instruments (CSI) , respectively.
  • Figure 6 is a side view of a coaxial electrosurgical instrument according to a preferred embodiment of this invention.
  • Figure 7 (A) is a longitudinal cross-sectional view of the distal operating end of this invention according to the preferred embodiment, namely one in which the coaxial inner electrode has a bent end part;
  • Figure 7(B) is an external side view of the same portion of the instrument; and,
  • Figure 7(C) is an end view looking toward the electrodes in the same embodiment.
  • Figures 8 (A) , 8 (B) , and 8 (C) are respective longitudinal cross-sectional, side and end views of a second preferred embodiment of this invention, in which the inner electrode has an entirely straight end extending outwardly of the coaxial outer electrode.
  • Figure 9 is a view schematically illustrating how the bent end of the inner electrode according to the preferred embodiment per Figures 6, 7(A) , 7(B) and 7(C) may be used to make an incision into tissue, with the operating inner electrode distal end part and the tissue being cut thereby clearly visible.
  • Figure 10 is an enlarged perspective view of the operating end of the preferred embodiment, in use, either at the initiation of a cutting operation or as it would be used to provide local coagulation or catherization.
  • Figure 11 is a further enlarged view of the preferred embodiment to illustrate a manner of its use to hook a blood vessel in a patient to apply energy to cauterize the same.
  • Figure 12 is a first side view of a third preferred embodiment of the invention in which the coaxial inner electrode has an angled distal end part with a smoothly rounded bulbous tip.
  • Figure 13 is a second side view of the invention per Figure 12, but at a 90° displacement relative thereto, also about a longitudinal axis thereof.
  • Figure 14 is a longitudinal view corresponding to Figure 13.
  • Figure 15 explains the dimensional relationships and relative dispositions of the distal end portion of the third preferred embodiment per Figures 12-14.
  • Figure 4 illustrates in side view a known bipolar electrosurgical instrument 400 which comprises two coacting and pivotably related elements 402 and 404, mounted at a distal end of an elongate tubular body element 406. A proximal end of this elongate body 406 is coupled to a hand-held, user-graspable, scissors like handle 408.
  • Handle 408 comprises two pivotably cooperating elements 410 and 412 connected by suitable linkages to obtain corresponding pivoting movement between electrode elements 402 and 404 in known manner.
  • Note cable 414 which, in use, would be connected to a source of controlled electrical power input and has individual wires connected to electrode elements 402 and 404.
  • FIG. 5(A) schematically illustrates by solid lines an electrical field about the single electrode 500 of a monopolar electrosurgical instrument .
  • the electric field and time-varying electric currents extend through the tissue of the patient away from the single electrode 500.
  • the electric lines of force are shown as solid lines and the equipotential lines as broken lines.
  • B a bipolar electrosurgical instrument comprising two cooperating electrodes, for example 402 and 404, when both electrodes are in contact with the patient's tissue, the (solid) electric lines of force between these two electrodes and the equipotential lines (broken) are as best seen in Fig. 5(B) .
  • electric current will tend to be experienced by the patient's tissue at locations away from the cooperating electrodes 402 and 404.
  • a coaxial electrosurgical instrument comprising an inner electrode 550 and a coaxially surrounding outer electrode 560, the electric field is confined to be within the region between these two electrodes, as indicated in Fig. 5(C) .
  • An advantage of the coaxial electrosurgical instrument is that it has a very limited region within which an electric current has to flow through a patient's tissue in order to perform its intended functions of incision, coagulation, or cauterization. Therefore, by making the respective diameters of the inner and outer electrodes small enough, a surgeon using the instrument can very severely limit the amount of tissue affected by electric current generated by contact with the electrodes at the operating distal end of the instrument. For neurosurgery, cardiovascular procedures, and the like, this is either highly desirable or, in some cases, vital.
  • the coaxial electrosurgical instrument 600 has a long, thin tubular body 602 (much like the elongate body 406 of the bipolar instrument 400 illustrated in Figure 4) but a much simpler hand-held, user- graspable handle 604 through which electrical wiring 606 provides electrical power to the distal operating end 608 of the instrument.
  • a surgeon would hold the handle 604 and, by any conventional means, e.g., a thumb, foot, or otherwise operated switch, control the intensity, waveform, and duration of an electrical power supplied to the operating electrodes. This is discussed in greater detail in the following paragraphs.
  • Figures 7(A), 7(B) and 7(C) are related to a first preferred embodiment of this invention, and provide a detailed understanding of the operating end portion 608 of an instrument like that illustrated generally in Figure 6. It should be appreciated that the actual instrument may be several inches long, and that means of any suitable known type for controllably providing electrical power may be employed. In other words, it is the structure and functionality of the distal operating end of the instrument which is of significance and provides distinct advantages over the prior art. The manner of connecting the electrical power supply and controlling the electrical power flow therefore may be of known type and, while important, are not considered determinative of the novelty of this invention.
  • the distal end portion 608 of the preferred embodiment has a substantially coaxial structure around elongitudinal axis X-X.
  • This structure includes a cylindrical, wire-like, electrically conductive inner electrode 702 coaxial about axis X-X.
  • inner electrode 702 is provided with an electrically insulating sleeve 704 to ensure against electrical shorting with respect to other elements.
  • a conductive outer electrode 706 having the form of a thin elongate tube.
  • an electrically conducting tip element 708 which may be press-fitted or otherwise made virtually integral with the tubular structure of outer electrode 706.
  • An insulating sleeve 710 is provided over the outer cylindrical surface of outer electrode 706 at least to the very end where the tubular outer electrode body 706 ends fitted tightly to tip element 708.
  • Tip element 708 is generally cylindrical and has a reduced diameter portion 712 sized and shaped to be fitted to the end of tubular outer electrode 706 in intimate electrical contact therewith. Tip element 708 also has an uninsulated exposed end portion 714 which preferably has the same outer diameter as tubular body
  • Tip element 708 is preferably cut at its end so as to have an inclined end face 716 which makes an acute angle "a" with respect to central axis X-X.
  • end face 716 has a generally annular elliptic shape, as best seen in the view of Figure 7(B) .
  • tip element 708 The inside diameter of tip element 708 is made larger than the outside diameter of insulating sleeve 704 provided around inner electrode 702. An insulating cylindrical insert 718 is press fitted into tip element
  • Insert 718 is formed at its outermost end so that it has an angled face coplanar with the angled end face 716 of tip element 708. Therefore, closely surrounding the extreme distal end portion of inner electrode 702 there is the inclined end face 720 of insulating central insert 718 which virtually acts as a sliding journal bearing for the distal end portion of inner electrode 702. Projecting outwardly of the plane of end faces 720 and 716 is a predetermined length 722 of inner electrode 702 which in the first preferred embodiment is straight and coaxial with axis X-X.
  • this projecting portion of the inner electrode 702 is bent so that an extreme end part 724 thereof is virtually at 90° with respect to access X-X.
  • the exact shape of the bend or curve involved is considered a matter of design choice, the key being that there is a sufficient length of portion 724 to enable a user to hook a portion of the tissue which is to be operated on by the device.
  • this end part 724 of inner electrode 702 ends in an end face 726 which does not extend radially, relative to axis X-X, any further than the outside surface of tip element 708.
  • tip element 408 has the same external diameter as the outer surface of the outer electrode 706. This is only the preferred structure, and persons of ordinary skill in the art may be expected to cause the end part 724 to be somewhat shorter or somewhat longer depending on particular applications of interest. There are certain advantages to the preferred embodiment as illustrated in
  • FIGS 8(A) , 8(B) and 8(C) Another structurally somewhat simpler embodiment is illustrated in Figures 8(A) , 8(B) and 8(C) .
  • the only significant difference between this second embodiment and the preferred embodiment per Figures 7(A) , 7(B) and 7(C) lies in the fact that in the second embodiment the inner electrode is entirely straight all the way through to its end face 826 which is preferably at right angles to the common access X-X.
  • All the other elements, particularly the insulating sleeves 704 and 710 (of the inner and outer electrodes 702 and 706, respectively), the tip element 708, and the like are exactly the same in shape and function as in the preferred embodiment according to Figures 7(A) , 7(B) and 7(C) .
  • insulating insert 718 in both embodiments has an angled end fact 720 coplanar with the angled end face 716 of tip element 714, and serves as an insulating sliding journal bearing for inner electrode 702.
  • Figures 8(A) , 8(B) and 8(C) does not have a bent end part.
  • the surgeon applies a downward pressure on tissue with the outer surface of tip element 708 and a pulling force simultaneously to the body 608 of the coaxial electrosurgical instrument per the preferred embodiment, with the angled face 716 uppermost where it can be viewed easily.
  • the extended portion 722 of the inner electrode is then pointing away from the surgeon and bent part 724 thereof is pressing into the tissue which is to be incised.
  • the end part 424 of inner electrode 702 is then making electrical contact at its end surface 726 with tissue 750.
  • tissue 750 is incised by the very high current density immediately between the bent part 724 of the inner electrode and the adjacent angled surface 716 which is part of the outer electrode.
  • the uninsulated exposed outer surface area of the outer electrode essentially the cylindrical surface 714 and the end face 716 of the tip element 708, is considerably larger than the uninsulated area of the exposed straight portion 722 and the bent part 724 (including end face 726) of the inner electrode 702. Because of this disparity in surface area sizes, the current density immediately surrounding the bent part 724 and the end face 726 of the inner electrode 702 will be very high and will cause explosive disruption of the contacted tissue cells, resulting in clean hemostatic cut, provided electrical power is delivered in an amount and at a frequency suited to the particular tissue.
  • the surgeon could turn the tool 180° relative to the above-described mode of application, so that a patient's tissue is contacted by the outer surface 714 of tip element 708, i.e., by the outer electrode 706, as well as by the curved outer surface the bend in the uninsulated portion of the inner electrode 702. There would be no hooking of the tissue under these circumstances, but upon delivery of the right amount of electrical power at the right frequency a surgeon may be able to make incisions. The difference is that in the first-described disposition it was the narrow leading wedge-shaped portion of the tip element 708 which depressed the tissue at 752 and allowed the surgeon a clear view of how and where the bent part 724 of the inner electrode was performing its cutting function.
  • FIG 11 illustrates one such procedure with the preferred embodiment per Figures 7(A) , 7(B) and 7(C) .
  • the surgeon employs the bent part 724 to hook over a blood vessel 1100. By tugging on the blood vessel in this manner, the surgeon can cause local collapse of the walls of the vessel and, by appropriate delivery of electrical power generate a local electrical burn and sealing of the vessel.
  • the second embodiment per Figs. 8(A), 8(B) and 8(C) can be used to perform substantially the same sort of functions of incision, coagulation, and cauterization as described with respect to the preferred embodiment per Figs. 7(A) , 7(B) and 7(C) .
  • the only distinction is that there is no bent part with which to hook tissue, so that there has to be pressure applied by the outer cylindrical surface of that portion of the inner electrode 702 which extends beyond the inclined end face 716 of the outer electrode, i.e., the tip element 708 thereof.
  • the second embodiment it would not be possible for a surgeon to hook a blood vessel as was possible with the first embodiment as just described with reference to Figure 11.
  • Both inner electrode 702 and outer electrode 706, as well as tip element 708, may be made a non-corrodible metal such as stainless steel.
  • Insulating sleeves 704 and 710, as well as insulating insert 718, may be made of a known chemically inert electrically insulating material such as TeflonTM or nylon.
  • a modified form of the structure has therefore been developed to improve the cauterization and coagulation capability of the device without sacrificing any of the other advantages, e.g., speed, flexibility in performing incisions, coagulation and cauterization without changing instruments, ability to operate in very confined quarters, and the like.
  • This embodiment of the invention is particularly suitable for surgery performed laparscopically as it makes it easier to keep both the inner and outer electrodes in contact with the tissue being operated on and to modulate the applied electrical power during use.
  • a third preferred embodiment 1200 of this invention the most noticeable structural difference as compared with the first preferred embodiment per Figures 7(A) - 7(C) , is in the physical form of the extreme distal end portion of the inner electrode 722. Since numerous other elements and features of the structure are exactly the same as in the first preferred embodiment per Figures 7(A) - 7(C) , the same numbering system will be employed to identify such common counterpart elements and features in Figures 12-14.
  • the distal end portion of inner electrode 702 was contained within and surrounded by an insulating cylindrical insert 718 press-fitted into tip element 708 at the end of the outer electrode 706, and insert 718 was formed at its outermost end to have an angled base coplanar with the angled end face 716 of tip element 708.
  • the same structure could be employed in the third preferred embodiment per Figures 12-14, but these figures illustrate yet another acceptable option.
  • this option instead of an insulating sleeve 704 and a separate coaxial insulating cylindrical insert 718 at the end, there may be provided a single cylindrical insulating element 1218 tightly fitted to the outer surface of the inner electrode 702. This insulating element 1218 extends just slightly beyond the angled surface 716 of tip 708.
  • angled distal end portion 1224 is sized so that a portion of it extends forwardly of the leading edge where slanted face 716 and the cylindrical outer surface of tip 708 intersect at the leading edge 1230.
  • the very distal end of angled end portion 1224 of inner electrode 702 is formed to have a smoothly rounded bulbous end 1250 which has a smooth, substantially spherical, curved surface 1260 extending forwardly of leading edge 1230 and also extending outwardly of the outer cylindrical surface of tip 708 in a radial direction. Preferred but not limiting dimensional relationships of the distal end portion of the third preferred embodiment are best understood with reference to Figure 15.
  • inner electrode 702 has the form of a thin straight wire contained within insulating element 1218 to be electrically insulated from and coaxial with cylindrical tip element 708 of the outer electrode.
  • the uninsulated exposed portion 722 of inner electrode 702 is preferably angled so that a distal end portion 1224 thereof lies substantially parallel to angled end face 716 of tip element 708.
  • the very distal end material is formed to have a smoothly rounded bulbous shape integral with the distal end portion 1224.
  • This bulbous end 1250 due to the surface tension of the molten material when locally heated, will have a virtually spherical shape with a smooth curved outer surface 1260.
  • the bulbous end 1250 be formed to have a diameter "d 2 " which is at least twice the size of "d-. " .
  • the smooth curved surface 1260 extend radially outward of the cylindrical outer surface of tip element 708 by a distance "r" which is preferably not less than one half of "d ⁇ ' .
  • the basic mode of operating the instrument according to the third preferred embodiment is the same as that described above for the second preferred embodiments. Basically, what is required is that both the outer uninsulated exposed surface of tip 708 of the outer electrode and the exposed uninsulated portion of the inner electrode make simultaneous physical and electrically-conductive contact with the patient's tissue at the selected surgical site. Then, when a high frequency alternating current is passed between the two electrodes, the resulting current passes between the leading edge 1230 and the immediately adjacent surface portion of the bulbous end surface 1260 of the inner electrode.
  • the operating surgeon can use the current passed through the tissue between the inner and outer electrodes to effect physical destruction of the tissue to create an incision.
  • the goal is always to prevent passage of this electrical current through any more of the patient's body than the tissue which is to be incised.
  • the effectiveness of the apparatus therefore depends on two principal factors: first, that both electrodes be in electrically conductive contact exactly as, when, and where desired by the surgeon; and, second, that the total surface area of tip 708 of the outer electrode in contact with the patient's tissue be significantly larger than the comparable tissue-contacting uninsulated exposed surface area of the inner electrode.
  • the desired incision will be performed very efficiently and, perhaps, too quickly to avoid leakage of body fluids to an undesired extent at the surgical cite. It is not, however, desirable to make the inner electrode thicker to thereby provide it with a relatively large uninsulated tissue-contactable exposed surface area.
  • the solution provided by the third preferred embodiment, as best understood with Figure 15, is to cause the very end of the exposed portion of the inner electrode to have an enlarged surface area. This is done most economically and efficiently by temporarily causing local melting of the material of the inner electrode at its very end and then cooling it, the resulting tape being, as illustrated, a virtually spherical smooth curved bulbous end.
  • the inner electrode By careful bending and placement of the inner electrode within the insulating element 1218 which is itself tightly fitted into the hollow interior of tape element 708, in a manner well understood by persons of ordinary skill in the art of microengineering, it is relatively easy to ensure that the smoothly curved surface 1260 is located so that a portion thereof extends radially outward of tip element 708 by a selected small distance "r" .
  • tissue 1310 e.g., the lining of the stomach or intestine of a patient
  • tissue 1320 a portion 1320 of the tissue pressed within the gap between leading edge 1230 of the outer electrode tip and the curved bulbous end surface 1260 of the inner electrode is in effect gently hooked or caught there. If the surgeon then applies an incising current, only this tissue will be primarily affected.
  • the surgeon has the ability to smoothly incise, coagulate incidental fluids, and cauterize tissues at a very confined surgical site with a single instrument simply by adjusting the powered input to the device as and when needed. This is found to be less stressful to the surgeon and of particular help where highly sensitive tissue must be operated on, e.g., in neurosurgery, in laparscopic surgery when the surgeon has to be guided by optically obtained and displayed images rather than direct line-of- sight viewing, and where due to trauma or otherwise there is a tendency for the tissue to leak excessive amounts of body fluids.
  • tissue-contactable uninsulated surface area of the inner electrode 702 at least less than half the corresponding tissue-contactable uninsulated area of the outer electrode 706 (i.e., the surface corresponding to its integral tip-element 708) will ensure good current density.

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Abstract

La présente invention concerne un instrument d'électrochirurgie à structure coaxiale, constitué d'une électrode interne (702) de forme allongée, isolée d'une électrode externe (706) tubulaire, creuse et de forme allongée, contenant l'électrode interne. Une différence de potentiel haute fréquence régulée est appliquée entre les électrodes sous la commande de l'utilisateur lorsque les parties non isolées des extrémités distales sont simultanément mises en contact avec le tissu. Lorsqu'on applique de façon continue entre les électrodes une différence de potentiel haute fréquence régulée non amortie, le courant qui circule tranche facilement et nettement le tissu entre les électrodes. Une différence de potentiel à amortissement périodique de fréquence permet la cautérisation et la coagulation. La surface terminale (716) de l'extrémité distale de l'électrode externe est de préférence inclinée, la zone d'extrémité terminale (726) de l'électrode interne coopérante étant elle-même inclinée selon un axe commun des électrodes. Le bout(1250) de cette zone d'extrémité terminale est de forme bulbeuse en léger arrondi, ce qui permet d'établir avec le tissu le contact pour exécuter des opérations chirurgicales. Ce bout bulbeux en arrondi de l'électrode interne dépasse non seulement vers l'avant de l'électrode externe mais aussi radialement à l'extérieur de cette électrode externe, grâce à quoi il est possible d'appliquer une action légère de crochetage permettant de maintenir le tissu entre les électrodes pour faciliter la réalisation précise d'opérations chirurgicales sur ce tissu.
PCT/US1996/012065 1995-07-21 1996-07-22 Instrument electro-chirurgical coaxial WO1997003619A2 (fr)

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AU65068/96A AU6506896A (en) 1995-07-21 1996-07-22 Coaxial electrosurgical instrument

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US50554395A 1995-07-21 1995-07-21
US08/505,543 1995-07-21

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WO1997003619A3 WO1997003619A3 (fr) 1997-03-06

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999065378A3 (fr) * 1998-06-17 2000-06-29 Nuvotek Ltd Outil coupant electrochirurgical
WO2022007732A1 (fr) * 2020-07-08 2022-01-13 安瑞医疗器械(杭州)有限公司 Outil haute fréquence ayant de multiples fonctions

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US4936301A (en) * 1987-06-23 1990-06-26 Concept, Inc. Electrosurgical method using an electrically conductive fluid
US5009656A (en) * 1989-08-17 1991-04-23 Mentor O&O Inc. Bipolar electrosurgical instrument
US5261906A (en) * 1991-12-09 1993-11-16 Ralph Pennino Electro-surgical dissecting and cauterizing instrument
US5267994A (en) * 1992-02-10 1993-12-07 Conmed Corporation Electrosurgical probe

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Publication number Priority date Publication date Assignee Title
US4936301A (en) * 1987-06-23 1990-06-26 Concept, Inc. Electrosurgical method using an electrically conductive fluid
US5009656A (en) * 1989-08-17 1991-04-23 Mentor O&O Inc. Bipolar electrosurgical instrument
US5261906A (en) * 1991-12-09 1993-11-16 Ralph Pennino Electro-surgical dissecting and cauterizing instrument
US5267994A (en) * 1992-02-10 1993-12-07 Conmed Corporation Electrosurgical probe

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999065378A3 (fr) * 1998-06-17 2000-06-29 Nuvotek Ltd Outil coupant electrochirurgical
US6786906B1 (en) 1998-06-17 2004-09-07 Nuvotek Ltd. Electrosurgical cutting tool
WO2022007732A1 (fr) * 2020-07-08 2022-01-13 安瑞医疗器械(杭州)有限公司 Outil haute fréquence ayant de multiples fonctions

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WO1997003619A3 (fr) 1997-03-06
AU6506896A (en) 1997-02-18

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