EP1135073A1 - Electrode de retour resistive et reutilisable pour electrochirurgie - Google Patents

Electrode de retour resistive et reutilisable pour electrochirurgie

Info

Publication number
EP1135073A1
EP1135073A1 EP99935675A EP99935675A EP1135073A1 EP 1135073 A1 EP1135073 A1 EP 1135073A1 EP 99935675 A EP99935675 A EP 99935675A EP 99935675 A EP99935675 A EP 99935675A EP 1135073 A1 EP1135073 A1 EP 1135073A1
Authority
EP
European Patent Office
Prior art keywords
sheet
patient
return electrode
working surface
electrode
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP99935675A
Other languages
German (de)
English (en)
Other versions
EP1135073A4 (fr
Inventor
Richard P. Fleenor
David B. Kieda
James D. Isaacson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MegaDyne Medical Products Inc
Original Assignee
MegaDyne Medical Products Inc
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 MegaDyne Medical Products Inc filed Critical MegaDyne Medical Products Inc
Publication of EP1135073A1 publication Critical patent/EP1135073A1/fr
Publication of EP1135073A4 publication Critical patent/EP1135073A4/fr
Withdrawn legal-status Critical Current

Links

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
    • A61B18/08—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by means of electrically-heated probes

Definitions

  • This invention relates to electrosurgery and, more particularly, to return electrodes that are adapted for providing effective and safe electrosurgical energy return without conducting or dielectric gels or polymers and which are reusable.
  • RF radio frequency
  • electrosurgery is widely used and offers many advantages including that of the use of a single surgical tool for both cutting and coagulation.
  • Every monopolar electrosurgical generator system to be fully used, must have an active electrode which is applied by the surgeon to the patient at the surgical site to perform surgery and a return path from the patient back to the generator.
  • the active electrode at the point of contact with the patient must be small in size to produce a high current density in order to produce a surgical effect of cutting or coagulating tissue.
  • the return electrode which carries the same current as the active electrode, must be large enough in effective surface area at the point of communication with the patient such that a low density current flows from the patient to the return electrode.
  • Electrode Contact Quality Monitoring System that would monitor the contact area of the electrode that is in contact with the patient and turn off the electrosurgical generator whenever there was insufficient contact area.
  • Such circuits are shown, for example, in United States patent
  • the present invention overcomes the problems of the prior art and provides a return electrode that eliminates patient burns without the need for expensive disposable electrodes and monitoring circuits in specialized RF generators.
  • the improved return electrode according to the preferred embodiment of the invention hereof includes an effective surface that is larger than other return electrodes that have been disclosed or used in surgery previously. It is so large and so adapted for positioning relative to the body of a patient that it eliminates the need for conductive or dielectric gels or polymers.
  • the exposed surface is of a material that is readily washable and/or sterilizable so as to facilitate easy and rapid conditioning for repeated reuse.
  • an electrosurgical return electrode is made sufficiently large to present sufficiently low electrical impedance and current densities at typical electrosurgery frequencies used in medical procedures so as to avoid excessive temperature elevation in adjacent patient tissue (i.e., above six degrees (6 °)
  • the working surface of the electrode (the electrode surface that is in contact with or in close proximity to the patient) is made sufficiently large in area so that in normal use, current flow will not be reduced to a point where it impedes the surgeon's ability to perform surgery at the surgical site
  • the electrosurgical return electrode is a simple single-layer construction, thus minimizing cost
  • controlled electrical conductivity is imparted to the single layer of material by the inclusion therein of electrically conductive materials such as conductive threads or carbon black, thus conditioning conductivity as a function of surface area to levels which limit passage of current therethrough to safe values.
  • a moisture impervious working surface is provided for positioning adjacent an adjoining surface of the body of a patient, thus facilitating cleansing and reuse of the electrosurgical electrode.
  • the aforementioned moisture impervious working surface is made resistant to normally encountered sterilizing agents, thus further facilitating cleansing and reuse.
  • a sleeve is provided for cooperative use with the electrosurgical electrode, thus protecting the electrode from inadvertent damage that might occur, for example, from accidental contact of the active electrosurgical instrument with the electrode surface.
  • the resistance of the materials in and adjacent the working surface of the electrode is sufficiently elevated so as to limit current density at the working surface to a level below the threshold of patient tissue trauma, thus providing a self-limiting characteristic to prevent patient trauma in the event of accidental reduction of the effective working surface of the electrode.
  • the electrosurgical electrode is form-fitted to the operating table on which the electrosurgical procedure is to be performed, thus facilitating realization of other features of the invention.
  • Figure 2 A is a top view of a wide-area distributed electrosurgical return electrode illustrating the principles of the invention.
  • Figure 2B is an enlargement of a segment of the electrosurgical return electrode of Figure 2A;
  • Figure 2C is a cross section taken along the section lines 2C-2C of Figure 2B and illustrating the effective circuit impedance represented by the segment of 2B;
  • Figure 3 is a chart illustrating in graphical form the relationships between effective surface area of the return electrode and the effective radio frequency current density developed at the electrode;
  • Figure 4 is a perspective view showing an operating table with the electrosurgical return electrode according to the invention disposed on the upper surface thereof;
  • Figure 5 is a front view illustrating a surgical chair with an electrosurgical return electrode according to the invention disposed on the surface of the seat thereof;
  • Figure 6 is a top view of an electrosurgical return electrode according to the invention.
  • Figure 7 is a section taken along the lines 7-7 of Figure 6;
  • Figure 8 is a section similar to that of Figure 7 but illustrating capacitance presented by a patient's surgical gown;
  • Figure 9 is a perspective view of a cover adapted for encasing any of the embodiments of Figures 6-8;
  • Figure 10 is a view illustrating one of the embodiments of Figures 6-8 encased within the cover of Figure 9;
  • Figure 11 is a perspective view illustrating, for the purpose of analysis, the circuit equivalent of a patient in operative association with the resistive and conductive regions of a pad according to the invention
  • Figure 12 is a simple electronic schematic circuit equivalent to Figure 11;
  • Figure 13 is a graph depicting percent capacitive coupling as a function of bulk resistivity of the insulating layer for different electrosurgical operating frequencies;
  • Figure 14 is a perspective view of a pad according to the invention illustrating a simulated condition when the effective contact area with a patient is substantially less than the physical pad size;
  • Figure 15 is a view illustrating current flow density within the pad when the effective patient contact area is much smaller than the total resistive pad area.
  • Figure 16 is a graph showing minimum bulk resistivity as a function of pad thickness for different electrosurgical generator frequencies.
  • FIG. 1 it will be seen to depict a simplified electrical schematic diagram illustrating typical impedances effectively included in the operative path of radio frequency current flow as presented to an electrosurgical generator during an operative procedure.
  • conventional radio frequency electrical power generator 10 to which there are connected conventional electrical conductors 11 and 12 which respectively connect the generator to the surgeon's implement represented by impedance z, and an electrosurgical return electrode represented by impedance z 3 .
  • Impedance z 2 is provided to represent the impedance presented by the patient's tissue lying between the operation site and the return electrode.
  • the initial embodiment hereof is that of an electrode operating in a substantially resistive mode. Accordingly, if the relatively small distributed capacitive and inductive reactances are disregarded, the total effective impedance of the circuit will be equal to the sum of the individual impedances z,, Zj and z 3 ; and since essentially the same current will pass through all three, the voltage generated by RF generator 10 will be distributed across impedances z,, z 2 and z 3 (which in this case are principally resistive in nature) in direct proportion to their respective values. Thus, the energy released in each of such principally resistive impedances will also be directly proportional to their values.
  • the resistive component of the impedance represented by z be substantial and that current passing therethrough (and consequent energy release) be concentrated in a very small region. The latter is accomplished by making the region of contact with the patient at the operative site very small.
  • FIG 2A there will be seen a top view of a wide-area distributed electrosurgical return electrode 20 illustrating the principles of the invention.
  • an electrical connection terminal 22 to facilitate connection to an electrical return conductor, such as conductor 12 of Figure 1.
  • the surface 20 A of return electrode 20 is preferably smooth and homogeneous.
  • electrode 20 may be thought of as including a plurality of uniformly-sized regions or segments as represented by regions 21, 21a, 21b, 21c . . . . . 2 In.
  • Region/segment 21 is shown larger in Figure 2B in order to be similar in scale to the resistive impedance z 3 ' it represents.
  • each of the segments of electrode 20 corresponding to segments 21 . . . 21n inherently has the capability of presenting an impedance similar to that of impedance z 3 '.
  • the number of such segments which are effectively active in parallel within the circuit is a direct function of the surface area of the patient that overlies the electrode.
  • the effective resistance would rise to a level, e.g., 250 ohms, so as to prevent effective use of the instrument by the surgeon, thus signaling the surgeon that the patient should be repositioned so as to present a greater surface area in contact with the return electrode.
  • the total circuit impedance would be increased so that the total current that would flow if the surgeon attempted to employ his instrument without repositioning the patient would be reduced to a value below that which would cause undesired trauma to the patient. Accordingly, there is provided a self-limiting feature that enhances safety in use without the need for the aforementioned separate circuit monitoring and control circuits.
  • Figure 2C is a cross section taken along the section lines 2C-2C of Figure 2B and illustrating the effective circuit impedance z 3 ' represented by the segment 21 of 2B.
  • segment 21 with its upper patient-contacting surface 24 represented electrically by terminal 23 and its lower surface 25 represented by electrical terminal 22A.
  • the impedance z 3 ' may be thought of as existing between terminals 23 and 22A.
  • each of the impedances represented by the remaining segments are connected at their lower extremities in parallel to terminal 22; whereas, if such highly conductive layer is absent, then, in addition to the impedance represented by the material lying between the upper and lower regions of each segment, there will be an additional impedance (not shown) that is represented by the material through which current would have to pass transversely or laterally through the electrode in order to get to terminal 22.
  • Figure 3 is a chart generally illustrating in graphic form the relationships between the effective surface area of the return electrode and the effective radio frequency current densities developed at the electrode.
  • the chart is simplified so as to illustrate the principles underlying the invention and does not represent actual data that may vary substantially.
  • RF Current Density versus Electrode Effective Surface Area the latter (as should now be evident to those skilled in the art) being that part of the surface of the return electrode that makes effective electrical contact with the body of a patient.
  • FIG 4 it will be seen to illustrate in perspective an operating table 40 with an electrosurgical return electrode 41 according to the invention disposed on the upper surface thereof, an edge of which is identified by the numerals 42.
  • the operating table is shown to have conventional legs 44a-44d that may be fitted with wheels or rollers as shown.
  • return electrode 41 the entire upper surface of the table is shown as being covered with return electrode 41, it should be understood that entire coverage is by no means required in order to practice the principles of the invention.
  • the return electrode when used with conventional electrosurgical generators, the return electrode needs only to present an effective working surface area which is sufficient to provide adequate resistive coupling at the typically employed RF frequencies so as not to interfere with the surgeons ability to perform surgery while at the same time avoiding undesired tissue damage. It has been found that at conventional electrosurgical frequencies, this has necessitated only an effective working surface area no more than about as large as the projected outline of one-half of the torso for an adult patient lying on an operating table or the buttocks of a patient sitting in a chair such as is illustrated in Figure 5. However, the effective working surface area will vary dependant upon the material used and in some geometrical configurations and in instances where various layers of operating room linens are placed over the electrode. The principles hereof may be successfully employed and the effective working surface area of the return electrode determined in such circumstances by routine experimentation.
  • the return electrodes shown in Figures 6-9 are depicted as being rectangular in shape, it will be evident that they could be oval or contoured as, for example, to follow the silhouette of the torso or other principal part of the body of a patient.
  • the electrode be of sufficient size so that when it is in use: (1) the return current density on the surface of the patient is sufficiently low; (2) the electrical impedance between it and the patient is sufficiently low so that insufficient electrical energy is concentrated to heat the skin of the patient at any location in the electrical return path by more than six (6°) degrees Celsius; and (3) the characteristics of the materials and geometries are such that if the effective area of the electrode is reduced below a selected threshold level, there will be insufficient energy dissipated at the surgeon's implement for him to continue effectively using the implement in its electrosurgical mode.
  • Xc capacitive reactance in ohms
  • ⁇ 3.14159
  • f frequency in hertz
  • C capacitance in farads.
  • a return electrode according to the invention hereof would need an effective area of eighteen square inches with a relatively small separation from the skin of the patient such as that provided by a surgical gown or no interposing gown at all. Such an effective area is easy to obtain if the patient is positioned on an electrode that is the size of their upper torso or larger.
  • FIG. 5 is a front view illustrating a surgical chair 50 with an electrosurgical return electrode 51 according to the invention disposed on the upper surface of the seat thereof.
  • FIG. 6 is a top view of another electrosurgical return electrode according to the invention. It will be observed that the upper exposed, or working, surface of the electrode again is expansive so as to meet the foregoing criteria for low impedance.
  • the electrode cover the entire surface of an operating table or the entire seat surface of a dental or other patient chair, it has been found advantageous in some instances to provide a greater surface area than that of the projected area of the buttocks or torso of a patient so that if a patient moves position during the course of a procedure, a sufficient portion of the patient outline will remain in registration with the electrode surface and the effective impedance will remain less than the above-described level.
  • the electrode does not need to be in contact with a patient either directly or through intervening conductive or nonconductive gel.
  • the electrode because of its expansive size, there is no need for tailoring the electrode to fit physical contours of a patient.
  • the preferable range of exposed upper working surface area of the electrode lies in the range of from about 11 to 1500 square inches.
  • the electrode according to the invention hereof as illustrated in Figure 6, may be made of conductive plastic, rubber or other flexible material which, when employed in the electrode will result in an effective dc resistance presented by each square centimeter of working surface to be greater than 10 ohms. Silicon or butyl rubber have been found to be particularly attractive materials as they are flexible, as well as readily washable and sterilizable.
  • the main body of the return electrode may be made of inherently relatively high resistance flexible material altered to provide the requisite conductivity.
  • a preferred example of the latter is that of silicon rubber material in which there are impregnated conductive fibers such as those of carbon, or in which there have been distributed quantities of other conductive substances such as carbon black, quantities of gold, silver, nickel, copper, steel, iron, stainless steel, brass, aluminum, or other conductors.
  • FIG. 6 reveals the presence of a conventional electrical connector 54 attached to the electrode 41 to provide a conventional electrical return to the electrosurgical radio frequency energy source (not shown).
  • Figure 7 is a section taken along the lines 7-7 of Figure 6.
  • electrode 46 similar to electrode 20 of Figures 2A-2C, except that electrode 46 includes a thin highly-conductive lower stratum 46c to facilitate conduction of current outwardly to terminal 54.
  • the thickness of the electrode lies in a range from about 1/32 inch to l/4th inch, which, with the aforementioned range of resistance of the material, provides the required resistance together with desired physical flexibility for ease of use and handling.
  • Figure 8 is a section similar to that of Figure 7, but presenting a multiple layer embodiment illustrating the separation presented by a patient's gown according to the invention hereof. There, in Figure 8 are shown a layer 46a (similar to layer 46 of Figure
  • a conductive layer 47a of Figure 8 could comprise a sheet or screen of gold, brass, aluminum, copper, silver, nickel, steel, stainless steel, conductive carbon, or the like.
  • a dielectric layer 47 represents the capacitance presented through a surgical gown or the like to a major portion, e.g., at least half of the trunk portion or the buttocks and upper thigh regions of a patient.
  • Figure 9 is a perspective view of a sleeve 50 adapted for encasing any one of the embodiments of Figures 6-8.
  • a sleeve 50 adapted for encasing any one of the embodiments of Figures 6-8.
  • such a sleeve may preferably be made of any of a variety of known materials, such as vinyl plastics, polyester or polyethylene.
  • Figure 10 is a view illustrating one of the embodiments of Figures 6-8 encased within the sleeve of Figure 9. There, it will be seen, is outer surface 50a of sleeve 50; and shown encased within sleeve 50 for illustrative purposes is electrode 41 of Figure 6.
  • Figures 11-16 are set forth to define the geometries and characteristics of materials employed to obtain the foregoing self-limiting action.
  • Figure 11 depicts an electrosurgical pad 60 consisting of a conductive metal backing 61 and a semi-insulating layer 62 of material with bulk resistivity p, thickness t and area A.
  • the pad is in contact with another conducting layer 63 which represents a patient thereupon.
  • the circuit can be modeled as a resistor R in parallel with a capacitor C ( Figure 12).
  • the resistance R is related to the bulk resistivity p, area A, and thickness t by the formula
  • the ratio X is independent of the pad area and thickness, depending only upon K and p.
  • X »1 whereas for pure resistive power conduction, X «1
  • K ranges from 3 to 5.
  • Commercially available electrosurgical generators presently have operating frequencies ranging from 100 kHz to 2 Mhz.
  • Figure 13 illustrates the amount of capacitive coupling for various frequency electrosurgical generators.
  • a bulk resistivity of 100,000 Ohm cm is required for the majority of the current to be passed through capacitive coupling.
  • the lowest possible bulk resistivity number is nearly two orders of magnitude greater than that anticipated by the Twentier United States Patent No. 4,088,133; and, consequently, the capacitive coupling electrode grounding pad according to the invention hereof appears to be neither taught nor suggested by known prior art.
  • a product according to the invention hereof can be easily distinguished from previous art through a simple test of the bulk resistivity of the insulating material, independent of pad area or pad thickness i.e. a bulk resistivity of at least about 8,000 ohm cm.
  • the self-limiting feature of the electrosurgical ground pad arises due to the impedance of the pad.
  • This impedance may arise from resistive, inductive, or capacitive components, or a combination thereof.
  • resistive, inductive, or capacitive components or a combination thereof.
  • a single layer of insulation and a single layer of a conductor gives an impedance equivalent to a resistor in parallel with a capacitor.
  • the total impedance is
  • the total impedance of the electrosurgical pad should be less than 75 ⁇ under normal operating conditions. We therefore require
  • Figure 15 reveals current flow distribution through the resistive part of the pad when the upper contact area with the patient is much smaller than the total pad surface area. Current flows through parallel paths around the contact region thus reducing the overall resistance to current flow and thereby reducing the effective bulk resistivity about 10-20 percent.
  • the lighter region denotes heavier current flow, and the opaque regions little or no significant current flow.
  • the minimum resistivity for a pad of such thickness is about 8000 ⁇ cm to be self-limiting in a resistive mode as previously noted.
  • an improved electrosurgical return electrode characterized by being generally pad-shaped and evidencing the features of being self-limiting while being reusable, readily cleanable and obviating the necessity for use of conducting gels or supplementary circuit monitoring equipment.

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  • Health & Medical Sciences (AREA)
  • Surgery (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biomedical Technology (AREA)
  • Otolaryngology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Plasma & Fusion (AREA)
  • Physics & Mathematics (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Surgical Instruments (AREA)

Abstract

Cette invention concerne une électrode de retour réutilisable et de type coussin (41) que l'on utilise en électrochirurgie. Dans un mode de réalisation, cette électrode possède une surface de présentation ou de travail qui varie d'environ 100 à environ 20000 centimètres carrés. Dans un autre mode de réalisation, la surface de travail est au moins aussi grande que celle d'une projection d'environ la moitié du profil du tronc d'un patient. Dans un autre mode de réalisation encore, cette électrode possède une surface de travail qui est au moins aussi grande que celle d'une projection du profil du tronc et des jambes du patient. Cette électrode est conçue pour être disposée sur la surface de travail d'une table d'opération ou d'un fauteuil de dentiste immédiatement sous le patient traité par électrochirurgie. La très grande surface de travail de cette électrode élimine toute nécessité de contact direct ou de contact par l'intermédiaire de gels électroconducteurs. Grâce à l'utilisation de surfaces lavables, cette électrode peut être facilement nettoyée et réutilisée. La sélection des caractéristiques de résistance des matériaux dont est fait le corps principal de l'électrode ainsi que la découpe des formes géométriques de l'électrode permettent de limiter automatiquement la densité de courant et les hausses de température qui pourraient entraîner un traumatisme du patient. Cette invention concerne également un manchon (50) qui peut être utilisé avec l'électrode.
EP99935675A 1998-11-30 1999-07-20 Electrode de retour resistive et reutilisable pour electrochirurgie Withdrawn EP1135073A4 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US201998 1994-02-25
US20199898A 1998-11-30 1998-11-30
PCT/US1999/016223 WO2000032122A1 (fr) 1998-11-30 1999-07-20 Electrode de retour resistive et reutilisable pour electrochirurgie

Publications (2)

Publication Number Publication Date
EP1135073A1 true EP1135073A1 (fr) 2001-09-26
EP1135073A4 EP1135073A4 (fr) 2003-01-15

Family

ID=22748161

Family Applications (1)

Application Number Title Priority Date Filing Date
EP99935675A Withdrawn EP1135073A4 (fr) 1998-11-30 1999-07-20 Electrode de retour resistive et reutilisable pour electrochirurgie

Country Status (12)

Country Link
EP (1) EP1135073A4 (fr)
JP (2) JP2002531162A (fr)
KR (1) KR20010075658A (fr)
CN (1) CN1256069C (fr)
AU (1) AU757953B2 (fr)
BR (1) BR9914684B1 (fr)
CA (1) CA2345270C (fr)
HK (1) HK1039886B (fr)
IL (1) IL143434A0 (fr)
NZ (1) NZ509124A (fr)
WO (1) WO2000032122A1 (fr)
ZA (1) ZA200100163B (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6796828B2 (en) 2001-06-01 2004-09-28 Sherwood Services Ag Return pad cable connector
US7566332B2 (en) * 2003-11-06 2009-07-28 Boston Scientific Scimed, Inc. Methods and apparatus for dispersing current flow in electrosurgery
US8231614B2 (en) 2007-05-11 2012-07-31 Tyco Healthcare Group Lp Temperature monitoring return electrode
US8801703B2 (en) 2007-08-01 2014-08-12 Covidien Lp System and method for return electrode monitoring
US8523853B2 (en) 2008-02-05 2013-09-03 Covidien Lp Hybrid contact quality monitoring return electrode
US10980994B2 (en) * 2016-01-26 2021-04-20 Jens Axelgaard Dual-sided electrode pad
US11364076B2 (en) 2019-12-12 2022-06-21 Covidien Lp Monopolar return pad

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2052269A (en) * 1979-05-21 1981-01-28 Mochida Pharm Co Ltd Patient plate for electrosurgical unit
US4669468A (en) * 1979-06-15 1987-06-02 American Hospital Supply Corporation Capacitively coupled indifferent electrode
WO1998018396A1 (fr) * 1996-10-30 1998-05-07 Megadyne Medical Products, Inc. Electrode electrochirurgicale de retour reutilisable
WO1998018395A1 (fr) * 1996-10-30 1998-05-07 Megadyne Medical Products, Inc. Electrode de retour capacitive, reutilisable et a vocation electro-chirurgicale
US5836942A (en) * 1996-04-04 1998-11-17 Minnesota Mining And Manufacturing Company Biomedical electrode with lossy dielectric properties

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3089496A (en) * 1959-08-19 1963-05-14 Code Inc Control system for surgical apparatus
US3543760A (en) * 1968-03-11 1970-12-01 Medical Plastic Inc Disposable ground plate electrode
US4088133A (en) * 1976-09-13 1978-05-09 Products International Company Electrode for electrosurgical procedure
CA1111503A (fr) * 1977-04-02 1981-10-27 Isoji Sakurada Electrode biomedicale
US4166465A (en) * 1977-10-17 1979-09-04 Neomed Incorporated Electrosurgical dispersive electrode
DE3544443C2 (de) * 1985-12-16 1994-02-17 Siemens Ag HF-Chirurgiegerät
GB9306637D0 (en) * 1993-03-30 1993-05-26 Smiths Industries Plc Electrosurgery monitor and appartus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2052269A (en) * 1979-05-21 1981-01-28 Mochida Pharm Co Ltd Patient plate for electrosurgical unit
US4669468A (en) * 1979-06-15 1987-06-02 American Hospital Supply Corporation Capacitively coupled indifferent electrode
US5836942A (en) * 1996-04-04 1998-11-17 Minnesota Mining And Manufacturing Company Biomedical electrode with lossy dielectric properties
WO1998018396A1 (fr) * 1996-10-30 1998-05-07 Megadyne Medical Products, Inc. Electrode electrochirurgicale de retour reutilisable
WO1998018395A1 (fr) * 1996-10-30 1998-05-07 Megadyne Medical Products, Inc. Electrode de retour capacitive, reutilisable et a vocation electro-chirurgicale

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO0032122A1 *

Also Published As

Publication number Publication date
EP1135073A4 (fr) 2003-01-15
AU5110399A (en) 2000-06-19
BR9914684B1 (pt) 2008-11-18
CA2345270A1 (fr) 2000-06-08
JP2009066426A (ja) 2009-04-02
HK1039886A1 (en) 2002-05-17
HK1039886B (zh) 2006-12-29
CN1256069C (zh) 2006-05-17
WO2000032122A1 (fr) 2000-06-08
ZA200100163B (en) 2001-08-03
JP2002531162A (ja) 2002-09-24
CA2345270C (fr) 2009-04-07
NZ509124A (en) 2003-10-31
IL143434A0 (en) 2002-04-21
CN1328433A (zh) 2001-12-26
AU757953B2 (en) 2003-03-13
KR20010075658A (ko) 2001-08-09
BR9914684A (pt) 2001-07-24

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