|Publication number||US3913583 A|
|Publication date||Oct 21, 1975|
|Filing date||Jun 3, 1974|
|Priority date||Jun 3, 1974|
|Publication number||US 3913583 A, US 3913583A, US-A-3913583, US3913583 A, US3913583A|
|Inventors||William T Bross|
|Original Assignee||Sybron Corp|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (7), Referenced by (149), Classifications (15), Legal Events (4)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent 'Bross Oct. 21, 1975  CONTROL CIRCUIT FOR 3,699,967 10/1972 Anderson l28/303.14
ELECTROSURGICAL UNITS FOREIGN PATENTS OR APPLICATIONS Inventor: William BPOSS, Cincinnati, Ohio 1,439,302 l/1969 Germany 128/303.14 Assignee: Sybron Corporation, Rochester 642,239 5/1932 Germany 323/56 N.Y. I Primary ExaminerRichard A. Gaudet 22] Fled: June 1974 Assistant Examiner-Lee S. Cohen 2 APPL 475, 3 Attorney, Agent, or FirmTheodore B. Roessel; J.
Stephen Yeo  US. Cl. 128/303.l4; 323/6; 323/56;
330/8; 336/155 [571 ABSTRACT  Int. Cl. A6lB 17/36 A ontrol ir uit for electrosurgical units which conl Field Of 128/303J4, trols power levels to patient electrode in response to 33 /8; 6 load conditions thereof. A saturable reactor is connected in series between the output of the electrosur- References Cited gical unit and the patient electrodes. The saturable re- UNIT ED STATES PATENTS actor is biased by a control coil activated by a recti- 2,581,202 1/1952 Post 336/155 fied current crresponding the alternating current 2,735,979 2/1956 323,6 flowing between the patient electrodes which is an in- 2,856,498 l0/1958 Jones..... dication of the area of contact between the patient 3,061,828 10/1962 Hauck 323/6 and one of the electrodes. 3,601,126 8 1971 Estes 128 303.14 3,658,067 4/1972 Bross 128/303.14 7 Clams, 2 Drawlng Flgllres INDICATINGJ MEANS J 34 l l l l l 3,
US. Patent Oct. 21, 1975 OSCILLATOR MODULATION MEANS FIG. I
FROM OSCILLATOR ACTIVE PROBE l6 PALIgNT as W I? INDICATING MEANS PATIENT PLATE TO RECTIFIER DC OUTPUT FIG. 2
TO ACTIVE PROBE CONTROL CIRCUIT FOR ELECTROSURGICAL UNITS BACKGROUND OF THE INVENTION This invention relates generally to RF control circuits and more particularly concerns RF control circuits that are used in electrosurgical units. Electrosurgical units generate high frequency power for the cutting and collagulation of tissue under surgical conditions. The electrosurgical units supply a high frequency alternating current at power levels up to several hundred watts to electrodes usually consisting of an active probe and a relatively large dispersive plate generally known as a patient plate. The electrodes are available in various configurations to be selected by the surgeon according to the intended use. Alternating current enters at the surgical site from the active probe, passes through the body of the patient to the patient plate and then returns to the low or grounded terminal of the electrical surgical unit. The physiological effects produced by electrosurgery are a result of a very high current density at the interface of the surgical active probe and the body tissue. There are no physiological effects at the patient plate site because the same current flows out of the patient through a relatively large area. During an operation the active probe is placed in contact with the patient. The patient should be in continual electrical communication with the patient plate. In the case of low power coagulators, capacitive coupling between patient and ground is satisfactory. The current levels produced by high powered equipment, such as used in general and transurethral surgery require a direct contact patient plate return connection. In the latter situation there is potential danger associated with electrosurgery should the patient plate by improperly applied or if an initial electrical contact becomes interrupted. If there is no other ground connections and if no other part of the patient is in contact with electrical ground, the available surgical current will be so reduced that in most cases, the surgeon will be immediately aware of the problem and he would either stop the procedure and investigate or request that the power should'be increased. The latter could be dangerous as a subsequent return of electrical continuity would result in excessive power being dissipated at the surgical site. Also, should the resistance of the patient plate interface be high, any extraneous ground connection, such as a cardioscope ground lead, would act as a high frequency ground connection. The contact area of such an extraneous ground connection is likely to be too small for the magnitude of current present and a burn at this site is almost a certainty.
It is possible to include a monitoring device that insures high frequency continuity to the patient plate. However, this monitor cannot determine if the patient plate has sufficient area in contact with the patient. If
area contact isnt proper, some surgical current could is effective, but complicated because it requires filter circuits to prevent high frequency from adversely effecting electrosurgical device control circuitry.
It would be, therefore, highly desirable to provide a simpler control circuit,- either to be used alone or to supplement one of the prior types of patient plate monitoring systems to additionally determine whether the patient plate electrode is contacting the patient. Such a monitoring system should be passive and be able to reduce high frequency to a low value should there be a impedance condition at the patient plate interface or return cable.
It is the object of this invention to provide a new and improved control circuit for electrosurgical units to monitor the impedance of a patient plate interface and connecting cable.
It is also an object of this invention to provide a new and improved control circuit for electrosurgical units for controlling output as a function of contact area between patient and patient plate.
It is another object of this invention to provide a new and improved control circuit for connection in the output circuit of an electrosurgical unit for reducing high frequency current to a low value for sensing and increasing RF current to normal level only if a complete circuit exists between the active and the patient plate electrodes.
An additional object of this invention is to provide a new and improved control circuit for monitoring circuit conditions between active and patient plate electrodes and having a switching time in microseconds.
SUMMARY OF THE INVENTION A control circuit is disclosed that controls the high frequency output current of an electrosurgical unit as applied across patient electrodes in response to the load between said patient electrodes.
The control circuit includes a saturable reactor means having variable reactance windings connected in seriesbetween the electrosurgical unit and the active patient electrode. The high frequency return current is conducted through a bridge rectifier which produces a DC current which passes through a control winding of the saturable reactor. Under normal high frequency current flow the DC current will be sufficient to saturate the reactor, minimizing the impedance thereof. Should the high frequency current be less than normal the DC current will be correspondingly reduced, causing the reactor to appear as a series inductive reactance, further reducing the high frequency current flow. Since the reactor reactance is a function of patient to patient plate impedance, the control sequence requires that sufficient area'of contact be made between the patient and the patient plate electrode for the application of full power.
The saturable reactor means can include a three legged ferromagnetic core, with the variable reactance winding wound on the outer legs and connected so as to null out induced voltages that would adversely effect the control winding which is wound about the middle leg.
Electrostatic sheild material may be used between windings to prevent capacitive coupling.
An alternate construction of the variable reactor is to use two cores, which may be cup, U, vor toroid cores, each core having a variable reactance winding and a control coil.
Indicating means can be provided to alert the operator of the state of the variable reactor.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram of an electrosurgical unit which includes the control circuit of the invention.
FIG. 2 is an alternative embodiment of the control circuit of the invention.
DETAILED DESCRIPTION'OF THE DRAWING FIG. 1, an electrosurgical unit having an oscillator generates RF signals at hectowatt power levels. Such an oscillator may be a spark gap, a vacuum tube oscillator, or a solid state oscillator. Modulation means 12 are used by the surgeon to select the desired amplitude and modulation mode suitable to the surgical functions of the cutting, hemostasis, and coagulation which are dependent upon the shape of the output wave form. The oscillator 10 means also includes a activating switch which may be hand or foot operated. The output of the oscillator 10 goes to the control circuit 14 of the present invention and therefrom to patient electrodes comprising of an active probe 16 and a patient plate 17.
A saturable reactor 18 is used in the control circuit 14. The reactor 18 includes a three-legged magnetic core 20 substantially symmetrical. About the two outer legs 22, 24 of the core 20 are wound variable reactance windings 26, 28 having substantially equal number of turns. The variable reactance windings 26, 28 are wound and interconnected so as to cancel any induced voltage caused by magnetic flow in the core 20. The two variable reactance windings 26, 28 are connected in series with the output oscillator 10 of the electical surgical unit and the active probe l6.
About the center leg 30 of the core is wound a control winding 32.
The leads of the control winding 32 are connected to the DC terminals of a high frequency bridge rectifier 34. The AC terminals of the high frequency bridge rectifier are connected in series from the patient plate 17 to electrical ground through a first capacitor 36. A second capacitor 38 is placed across control winding 32 to level the ripple on the DC voltage. The amount of RF current passing through the patient will be dependent upon the impedance between the active probe 16 and the patient plate 17. The impedance is the sum of the patient resistance, typically between 400 and 500 ohms, and the interface resistance between the patient and the patient plate electrode 17. Should the patient plate 17 be improperly attached so as to have insufficient contact area between the patient and the patient electrode, the interface resistance will be high and the current at a given setting will be low campared to what it would be if the patient plate was correctly applied. The alternating RF current flows from the active probe 16 through the patient to the patient plate 17, through the high frequency rectifier 34 across the capacitor 36 to ground. The higher the amplitude of the RF current, the higher will be the rectified DC current passing through the control winding 32. Conversely, a poor connection will reduce the alternating RF current". The rectified DC current will be correspondingly lower reducing the current flowing through the control winding 32. When no DC current is present, the core material is unsaturated, and inductively loads the variable reactance windings 26, 28, effectively introducing a series reactance into the output circuit. This limits the output current to a low value typically..50 to milliamps when no DC control current is present. When a completed high frequency circuit is established, returning current passes through the rectified circuit 34, causing a DC current to flow through the reactor control winding 32 partly, saturating the core 20. This lowers the impedance of the reactance winding 26, 28 and increases the output current. The higher output current passes through the rectifier 34 further increasing the control winding current which completely saturates the reactor minimizing the reactance.
The core may be made of suitable ferromagnetic material such as ferrite. Unlike the usual saturable reactor it is not necessary for the core material to exhibit a square hysteresis loop. Details of the RF variable reactance windings include that the two coils are series connected but opposed so as to cancel any induced voltages in the DC control circuit. It is also important that the variable reactance windings 26, 28 are not coupled to the bias control circuit as RF passing through these windings could conceivably be coupled into the control winding 32 to be rectified by the high frequency rectifier 34 and affect the reactor. Therefore, electrostatic shield material 42 may be interposed between the outer 26, 28 and inner 30 legs to prevent capacitive coupling.
It would be desirable for the surgeon to be made aware of the condition of the control circuit. Indicating means 44 may be provided across the DC leads of the rectifier bridge circuit so as to be responsive to the amount of DC voltage and to provide indication thereof.
As shown in FIG. 2, an alternative method of making the saturable reactor is to use two cup cores 44, each having one RF winding 46 and one control winding 48 wherein the RF windings are connected so to cancel the induced voltage in the DC control winding. As herein defined, cup cores include U and toroid shaped cores.
The control circuit for disclosed units is a simple passive device that when connected in the output circuit of an electrosurgical unit, reduces high frequency current to a low value for sensing andincreases to normal level only if a complete circuit exists between the active probe and the patient plate. Switching time is in microseconds. Tests have been conducted with actual electrosurgical units using tubes, solid state and spark gap technologies over the frequency range of 500 kiloherz to 2.3 megaherz and the control circuit has been found to be both reliable and efficient.
I claim: i 1. In combination with an electrosurgical unit having an oscillator applying variable high frequency current to a plurality of patient electrodes, a control circuit comprising:
a saturable reactor connected between said oscillator and at least one of said patient electrodes; and
bias means responsive to current flow through said patient electrodes for biasing said saturable reactor to control the impedance thereof, whereby for a first range of current flow through said patient electrodes said saturable reactor represents an inductive reactance'to said oscillator and during a second range of current flow through said patient electrodes substantially greater than said first current flow said reactor represents a lower inductive reactance to said oscillator.
2. A control circuit as defined in claim 1, wherein said saturable reactor includes:
a ferromagnetic core;
a plurality of variable reactances windings, and
a control winding.
3. A control circuit as defined in claim 2, wherein said bias means includes:
a diode rectifying bridge connected between one of said patient electrodes and said control winding, said bridge having a DC current output corresponding to the amplitude of AC current flow, said DC output being applied to said control winding for biasing said saturable reactor.
4. A control circuit as defined in claim 3 which further includes an indicator means connected across said bias means so as to be indicative of said bias current and load conditions across said patient electrodes.
5. A control circuit as defined in claim 2, wherein said variable reactance windings are interconnected so as to nullify any induced voltage in said control winding.
6. A control circuit as defined in claim 5, which further includes an electrostatic shield means interposed between said variable reactance windings and said control windings.
7. A control circuit defined in claim 1, wherein said saturable reactor is comprised of:
two cup cores; at least one variable reactance winding wound abou each of said cup cores; and at least one DC control bias winding wound about each of said cup cores, whereas said variable reactance windings are connected in series so as to nullify the effect on said DC control coils winding.
UNITED STATES PATENT GFFICE CERTIFIQATE 0F COERECTEON Patent 3, 913, 583 I v D d October 21; 1975 Inventor(s) William T. Bross It is certified that error appears in the above-identified patent and that said Letters Patent: are hereby corrected as shown below:
Column 1, line 6L1- "exists" should be 7 --exits--. v
Column 2, line 63 "s heild" should be "Sm 91d".
Column 3, line 53 "camp ared" should be --compared--.
Signed and Scaled this tenth D3) Of February 1976 [SEAL] Arrest:
RUTH C. MA SON C. MARSHALL DANN Arresting Officer Commissioner ofParents and Trademarks UNITED STATES PATEP-ZT 0mm; CERTIFICATE 9F CGRRECHON Patent No, 3,913,583 Dated Octoloer 21,- 1975 Inventor(s) William T; Bross It is certified that error appears in the above-identified. patent and that said Letters Patent are hereby corrected as shown below: r
Column 1, line 6A "exists" should be --exits--.
Column 2, line 63 "s heild" 7 should be --sfii eld--,
Column 3, line 53 "campared" should be --compared--.
Engncd and Scaled this D tenth Day Of February 1976 [SEAL] Arrest:
RUTH C. MASON C. MARSHALL DANN Arresting Offive Commissioner oj'larents and Trademarks
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2581202 *||Nov 25, 1949||Jan 1, 1952||Rca Corp||Multistage variable-saturation tuning system and apparatus|
|US2735979 *||Feb 24, 1953||Feb 21, 1956||Input|
|US2856498 *||Oct 24, 1955||Oct 14, 1958||Delapena & Son Ltd||High frequency electric induction heating systems|
|US3061828 *||Mar 11, 1958||Oct 30, 1962||Basic Products Corp||Circuit means|
|US3601126 *||Jan 8, 1969||Aug 24, 1971||Electro Medical Systems Inc||High frequency electrosurgical apparatus|
|US3658067 *||May 19, 1969||Apr 25, 1972||Sybren Corp||Electro-surgical apparatus|
|US3699967 *||Apr 30, 1971||Oct 24, 1972||Valleylab Inc||Electrosurgical generator|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3964487 *||Dec 9, 1974||Jun 22, 1976||The Birtcher Corporation||Uncomplicated load-adapting electrosurgical cutting generator|
|US4184492 *||May 30, 1978||Jan 22, 1980||Karl Storz Endoscopy-America, Inc.||Safety circuitry for high frequency cutting and coagulating devices|
|US4200104 *||Nov 17, 1977||Apr 29, 1980||Valleylab, Inc.||Contact area measurement apparatus for use in electrosurgery|
|US4303073 *||Jan 17, 1980||Dec 1, 1981||Medical Plastics, Inc.||Electrosurgery safety monitor|
|US4494541 *||Nov 2, 1981||Jan 22, 1985||Medical Plastics, Inc.||Electrosurgery safety monitor|
|US4590934 *||May 18, 1983||May 27, 1986||Jerry L. Malis||Bipolar cutter/coagulator|
|US5335668 *||Apr 30, 1993||Aug 9, 1994||Medical Scientific, Inc.||Diagnostic impedance measuring system for an insufflation needle|
|US5413574 *||Oct 8, 1993||May 9, 1995||Fugo; Richard J.||Method of radiosurgery of the eye|
|US5417687 *||Apr 30, 1993||May 23, 1995||Medical Scientific, Inc.||Bipolar electrosurgical trocar|
|US5611798 *||Mar 2, 1995||Mar 18, 1997||Eggers; Philip E.||Resistively heated cutting and coagulating surgical instrument|
|US5658279 *||Mar 21, 1995||Aug 19, 1997||Medical Scientific, Inc.||Bipolar electrosurgical trocar|
|US5688269 *||Mar 30, 1993||Nov 18, 1997||Electroscope, Inc.||Electrosurgical apparatus for laparoscopic and like procedures|
|US5713896 *||May 10, 1995||Feb 3, 1998||Medical Scientific, Inc.||Impedance feedback electrosurgical system|
|US5772659 *||Sep 26, 1995||Jun 30, 1998||Valleylab Inc.||Electrosurgical generator power control circuit and method|
|US6156036 *||Jun 11, 1999||Dec 5, 2000||Alcon Laboratories, Inc.||Surgical handpiece tip|
|US6162216 *||Mar 2, 1998||Dec 19, 2000||Guziak; Robert Andrew||Method for biopsy and ablation of tumor cells|
|US6211749 *||May 12, 1999||Apr 3, 2001||Kyosan Electric Mfg. Co., Ltd.||Impedance matching device|
|US6251106||May 21, 1998||Jun 26, 2001||Sherwood Services Ag||Electrosurgical generator power control circuit and method|
|US6258085||May 11, 1999||Jul 10, 2001||Sherwood Services Ag||Electrosurgical return electrode monitor|
|US6325799||Apr 24, 1998||Dec 4, 2001||Gyrus Medical Limited||Electrosurgical instrument|
|US6409725||Feb 1, 2000||Jun 25, 2002||Triad Surgical Technologies, Inc.||Electrosurgical knife|
|US6565559||May 14, 2001||May 20, 2003||Sherwood Services Ag||Electrosurgical return electrode monitor|
|US6589239||Dec 13, 2001||Jul 8, 2003||Ashok C. Khandkar||Electrosurgical knife|
|US7044948||Dec 4, 2003||May 16, 2006||Sherwood Services Ag||Circuit for controlling arc energy from an electrosurgical generator|
|US7131860||Nov 20, 2003||Nov 7, 2006||Sherwood Services Ag||Connector systems for electrosurgical generator|
|US7137980||May 1, 2003||Nov 21, 2006||Sherwood Services Ag||Method and system for controlling output of RF medical generator|
|US7255694||Dec 4, 2003||Aug 14, 2007||Sherwood Services Ag||Variable output crest factor electrosurgical generator|
|US7276060||Feb 26, 2004||Oct 2, 2007||Alcon, Inc.||Surgical handpiece tip|
|US7300435||Nov 21, 2003||Nov 27, 2007||Sherwood Services Ag||Automatic control system for an electrosurgical generator|
|US7303557||Dec 27, 2004||Dec 4, 2007||Sherwood Services Ag||Vessel sealing system|
|US7364577||Jul 24, 2003||Apr 29, 2008||Sherwood Services Ag||Vessel sealing system|
|US7396336||Oct 27, 2004||Jul 8, 2008||Sherwood Services Ag||Switched resonant ultrasonic power amplifier system|
|US7416437||Aug 23, 2006||Aug 26, 2008||Sherwood Services Ag||Connector systems for electrosurgical generator|
|US7422589||Aug 12, 2005||Sep 9, 2008||Encision, Inc.||System and method for performing an electrosurgical procedure|
|US7425835||May 20, 2005||Sep 16, 2008||Erbe Elektromedizin Gmbh||Method and measurement apparatus for determining the transition impedance between two parts of a subdivided neutral electrode|
|US7465302||Aug 12, 2005||Dec 16, 2008||Encision, Inc.||System and method for performing an electrosurgical procedure|
|US7473145||Oct 18, 2007||Jan 6, 2009||Covidien Ag||Return pad cable connector|
|US7513896||Jan 24, 2006||Apr 7, 2009||Covidien Ag||Dual synchro-resonant electrosurgical apparatus with bi-directional magnetic coupling|
|US7554341||Jul 17, 2008||Jun 30, 2009||Erbe Elektromedizin Gmbh||Method and measurement apparatus for determining the transition impedance between two parts of a subdivided neutral electrode|
|US7628786||May 16, 2005||Dec 8, 2009||Covidien Ag||Universal foot switch contact port|
|US7637907||Sep 19, 2006||Dec 29, 2009||Covidien Ag||System and method for return electrode monitoring|
|US7648499||Mar 21, 2006||Jan 19, 2010||Covidien Ag||System and method for generating radio frequency energy|
|US7651492||Jan 26, 2010||Covidien Ag||Arc based adaptive control system for an electrosurgical unit|
|US7651493||Mar 3, 2006||Jan 26, 2010||Covidien Ag||System and method for controlling electrosurgical snares|
|US7722412||Oct 24, 2007||May 25, 2010||Covidien Ag||Return pad cable connector|
|US7722601||Apr 30, 2004||May 25, 2010||Covidien Ag||Method and system for programming and controlling an electrosurgical generator system|
|US7722603||Sep 28, 2006||May 25, 2010||Covidien Ag||Smart return electrode pad|
|US7731717||Aug 8, 2006||Jun 8, 2010||Covidien Ag||System and method for controlling RF output during tissue sealing|
|US7736359||Jan 12, 2006||Jun 15, 2010||Covidien Ag||RF return pad current detection system|
|US7749217||May 6, 2003||Jul 6, 2010||Covidien Ag||Method and system for optically detecting blood and controlling a generator during electrosurgery|
|US7766693||Jun 16, 2008||Aug 3, 2010||Covidien Ag||Connector systems for electrosurgical generator|
|US7766905||Feb 4, 2005||Aug 3, 2010||Covidien Ag||Method and system for continuity testing of medical electrodes|
|US7780662||Feb 23, 2005||Aug 24, 2010||Covidien Ag||Vessel sealing system using capacitive RF dielectric heating|
|US7794457||Sep 28, 2006||Sep 14, 2010||Covidien Ag||Transformer for RF voltage sensing|
|US7824400||Mar 3, 2006||Nov 2, 2010||Covidien Ag||Circuit for controlling arc energy from an electrosurgical generator|
|US7834484||Jul 16, 2007||Nov 16, 2010||Tyco Healthcare Group Lp||Connection cable and method for activating a voltage-controlled generator|
|US7871410 *||Oct 28, 2003||Jan 18, 2011||Cathrx Ltd||System for, and method of, heating a biological site in a patient's body|
|US7880577 *||Aug 25, 2006||Feb 1, 2011||Lockheed Martin Corporation||Current doubler rectifier with current ripple cancellation|
|US7901400||Jan 27, 2005||Mar 8, 2011||Covidien Ag||Method and system for controlling output of RF medical generator|
|US7927328||Jan 24, 2007||Apr 19, 2011||Covidien Ag||System and method for closed loop monitoring of monopolar electrosurgical apparatus|
|US7927329||Sep 28, 2006||Apr 19, 2011||Covidien Ag||Temperature sensing return electrode pad|
|US7938825||Nov 7, 2006||May 10, 2011||Covidien Ag||Multiple RF return pad contact detection system|
|US7947039||Dec 12, 2005||May 24, 2011||Covidien Ag||Laparoscopic apparatus for performing electrosurgical procedures|
|US7972328||Jan 24, 2007||Jul 5, 2011||Covidien Ag||System and method for tissue sealing|
|US7972332||Dec 16, 2009||Jul 5, 2011||Covidien Ag||System and method for controlling electrosurgical snares|
|US8007494||Apr 26, 2007||Aug 30, 2011||Encision, Inc.||Device and method to prevent surgical burns|
|US8012150||Apr 30, 2004||Sep 6, 2011||Covidien Ag||Method and system for programming and controlling an electrosurgical generator system|
|US8021360||Apr 3, 2007||Sep 20, 2011||Tyco Healthcare Group Lp||System and method for providing even heat distribution and cooling return pads|
|US8025660||Nov 18, 2009||Sep 27, 2011||Covidien Ag||Universal foot switch contact port|
|US8034049||Aug 8, 2006||Oct 11, 2011||Covidien Ag||System and method for measuring initial tissue impedance|
|US8062291||Mar 31, 2010||Nov 22, 2011||Covidien Ag||Smart return electrode pad|
|US8080007||May 7, 2007||Dec 20, 2011||Tyco Healthcare Group Lp||Capacitive electrosurgical return pad with contact quality monitoring|
|US8080008||Sep 18, 2007||Dec 20, 2011||Covidien Ag||Method and system for programming and controlling an electrosurgical generator system|
|US8096961||Jun 27, 2008||Jan 17, 2012||Covidien Ag||Switched resonant ultrasonic power amplifier system|
|US8100898||Aug 1, 2007||Jan 24, 2012||Tyco Healthcare Group Lp||System and method for return electrode monitoring|
|US8104956||Oct 23, 2003||Jan 31, 2012||Covidien Ag||Thermocouple measurement circuit|
|US8105323||Oct 24, 2006||Jan 31, 2012||Covidien Ag||Method and system for controlling output of RF medical generator|
|US8113057||Jun 27, 2008||Feb 14, 2012||Covidien Ag||Switched resonant ultrasonic power amplifier system|
|US8147485||Feb 23, 2009||Apr 3, 2012||Covidien Ag||System and method for tissue sealing|
|US8187262||Jun 3, 2009||May 29, 2012||Covidien Ag||Dual synchro-resonant electrosurgical apparatus with bi-directional magnetic coupling|
|US8202271||Feb 25, 2009||Jun 19, 2012||Covidien Ag||Dual synchro-resonant electrosurgical apparatus with bi-directional magnetic coupling|
|US8216220||Sep 7, 2007||Jul 10, 2012||Tyco Healthcare Group Lp||System and method for transmission of combined data stream|
|US8216222||Apr 13, 2011||Jul 10, 2012||Covidien Ag||Temperature sensing return electrode pad|
|US8216223||Feb 23, 2009||Jul 10, 2012||Covidien Ag||System and method for tissue sealing|
|US8226639||Jun 10, 2008||Jul 24, 2012||Tyco Healthcare Group Lp||System and method for output control of electrosurgical generator|
|US8231614||May 11, 2007||Jul 31, 2012||Tyco Healthcare Group Lp||Temperature monitoring return electrode|
|US8231616||Aug 23, 2010||Jul 31, 2012||Covidien Ag||Transformer for RF voltage sensing|
|US8235980||Dec 14, 2011||Aug 7, 2012||Tyco Healthcare Group Lp||Electrosurgical system for measuring contact quality of a return pad|
|US8241278||Apr 29, 2011||Aug 14, 2012||Covidien Ag||Laparoscopic apparatus for performing electrosurgical procedures|
|US8251989||Jun 13, 2007||Aug 28, 2012||Encision, Inc.||Combined bipolar and monopolar electrosurgical instrument and method|
|US8267928||Mar 29, 2011||Sep 18, 2012||Covidien Ag||System and method for closed loop monitoring of monopolar electrosurgical apparatus|
|US8267929||Dec 16, 2011||Sep 18, 2012||Covidien Ag||Method and system for programming and controlling an electrosurgical generator system|
|US8287528||Mar 28, 2008||Oct 16, 2012||Covidien Ag||Vessel sealing system|
|US8298223||Apr 5, 2010||Oct 30, 2012||Covidien Ag||Method and system for programming and controlling an electrosurgical generator system|
|US8303580||Apr 5, 2010||Nov 6, 2012||Covidien Ag||Method and system for programming and controlling an electrosurgical generator system|
|US8353905||Jun 18, 2012||Jan 15, 2013||Covidien Lp||System and method for transmission of combined data stream|
|US8382749||Jul 17, 2012||Feb 26, 2013||Covidien Lp||Temperature monitoring return electrode|
|US8388612||May 11, 2007||Mar 5, 2013||Covidien Lp||Temperature monitoring return electrode|
|US8430873||Jan 4, 2012||Apr 30, 2013||Covidien Lp||System and method for return electrode monitoring|
|US8460284||Jun 11, 2013||Encision, Inc.||Multiple parameter fault detection in electrosurgical instrument shields|
|US8475447||Aug 23, 2012||Jul 2, 2013||Covidien Ag||System and method for closed loop monitoring of monopolar electrosurgical apparatus|
|US8485993||Jan 16, 2012||Jul 16, 2013||Covidien Ag||Switched resonant ultrasonic power amplifier system|
|US8486061||Aug 24, 2012||Jul 16, 2013||Covidien Lp||Imaginary impedance process monitoring and intelligent shut-off|
|US8512332||Sep 21, 2007||Aug 20, 2013||Covidien Lp||Real-time arc control in electrosurgical generators|
|US8523853||Jan 23, 2009||Sep 3, 2013||Covidien Lp||Hybrid contact quality monitoring return electrode|
|US8523855||Aug 23, 2010||Sep 3, 2013||Covidien Ag||Circuit for controlling arc energy from an electrosurgical generator|
|US8556890||Dec 14, 2009||Oct 15, 2013||Covidien Ag||Arc based adaptive control system for an electrosurgical unit|
|US8568400 *||Sep 23, 2009||Oct 29, 2013||Covidien Lp||Methods and apparatus for smart handset design in surgical instruments|
|US8647340||Jan 4, 2012||Feb 11, 2014||Covidien Ag||Thermocouple measurement system|
|US8652125||Sep 28, 2009||Feb 18, 2014||Covidien Lp||Electrosurgical generator user interface|
|US8663214||Jan 24, 2007||Mar 4, 2014||Covidien Ag||Method and system for controlling an output of a radio-frequency medical generator having an impedance based control algorithm|
|US8685016||Feb 23, 2009||Apr 1, 2014||Covidien Ag||System and method for tissue sealing|
|US8690867||Feb 14, 2013||Apr 8, 2014||Covidien Lp||Temperature monitoring return electrode|
|US8734438||Oct 21, 2005||May 27, 2014||Covidien Ag||Circuit and method for reducing stored energy in an electrosurgical generator|
|US8753334||May 10, 2006||Jun 17, 2014||Covidien Ag||System and method for reducing leakage current in an electrosurgical generator|
|US8758336||Oct 13, 2009||Jun 24, 2014||Encision, Inc.||System and method for monitoring electrosurgical systems|
|US8777940||Apr 3, 2007||Jul 15, 2014||Covidien Lp||System and method for providing even heat distribution and cooling return pads|
|US8777941||May 10, 2007||Jul 15, 2014||Covidien Lp||Adjustable impedance electrosurgical electrodes|
|US8801703||Aug 1, 2007||Aug 12, 2014||Covidien Lp||System and method for return electrode monitoring|
|US8808161||Oct 23, 2003||Aug 19, 2014||Covidien Ag||Redundant temperature monitoring in electrosurgical systems for safety mitigation|
|US8821487||Mar 31, 2006||Sep 2, 2014||Covidien Ag||Temperature regulating patient return electrode and return electrode monitoring system|
|US8966981||Jul 16, 2013||Mar 3, 2015||Covidien Ag||Switched resonant ultrasonic power amplifier system|
|US9113900||Jan 31, 2012||Aug 25, 2015||Covidien Ag||Method and system for controlling output of RF medical generator|
|US9116179||Nov 1, 2013||Aug 25, 2015||Covidien Lp||System and method for voltage and current sensing|
|US9119624||Oct 8, 2013||Sep 1, 2015||Covidien Ag||ARC based adaptive control system for an electrosurgical unit|
|US9168089||Jan 31, 2012||Oct 27, 2015||Covidien Ag||Method and system for controlling output of RF medical generator|
|US9186200||May 30, 2012||Nov 17, 2015||Covidien Ag||System and method for tissue sealing|
|US20040119577 *||Nov 25, 2003||Jun 24, 2004||Robert Weger||Coil arrangement with variable inductance|
|US20050192566 *||Feb 26, 2004||Sep 1, 2005||Madden Sean C.||Surgical handpiece tip|
|US20050273091 *||Oct 28, 2003||Dec 8, 2005||Cathrxptyltd||System for, and method of, heating a biological site in a patient's body|
|US20060041251 *||Aug 12, 2005||Feb 23, 2006||Odell Roger C||Electrosurgical system and method|
|US20060041252 *||Aug 12, 2005||Feb 23, 2006||Odell Roger C||System and method for monitoring electrosurgical instruments|
|US20060041253 *||Aug 12, 2005||Feb 23, 2006||Newton David W||System and method for performing an electrosurgical procedure|
|US20070222458 *||May 20, 2005||Sep 27, 2007||Erbe Elektromedizin Gmbh||Method And Measurement Apparatus For Determining The Transition Impedance Between Two Parts Of A Subdivided Neutral Electrode|
|US20080278179 *||Jul 17, 2008||Nov 13, 2008||Florian Eisele||Method and measurement apparatus for determining the transition impedance between two parts of a subdivided neutral electrode|
|US20090112204 *||Oct 24, 2008||Apr 30, 2009||Encision, Inc.||Multiple Parameter Fault Detection in Electrosurgical Instrument Shields|
|US20090198229 *||Jan 23, 2009||Aug 6, 2009||Tyco Healthcare Group Lp||Hybrid Contact Quality Monitoring Return Electrode|
|US20110071520 *||Mar 24, 2011||Tyco Healthcare Group Lp||Methods and Apparatus for Smart Handset Design in Surgical Instruments|
|US20110077631 *||Mar 31, 2011||Tyco Healthcare Group Lp||Electrosurgical Generator User Interface|
|US20110190761 *||Aug 4, 2011||Covidien Ag||Temperature Sensing Return Electrode Pad|
|US20120239025 *||Mar 17, 2011||Sep 20, 2012||Tyco Healthcare Group Lp||Isolated Current Sensor|
|USRE40388||May 8, 2003||Jun 17, 2008||Covidien Ag||Electrosurgical generator with adaptive power control|
|DE3239640A1 *||Oct 26, 1982||May 19, 1983||Valleylab Inc||Monitoring arrangement for a return electrode|
|DE3249766C2 *||Oct 26, 1982||Aug 18, 1988||Valleylab, Inc., Boulder, Col., Us||Monitoring arrangement in a high-frequency surgical instrument|
|EP1034747A1 *||Mar 3, 2000||Sep 13, 2000||Gyrus Medical Limited||Electrosurgery system and instrument|
|EP1719471A2||Sep 11, 2003||Nov 8, 2006||Sherwood Services AG||Multiple RF return pad contact detection system|
|EP2258295A2||Sep 11, 2003||Dec 8, 2010||Covidien AG||Multiple RF return pad contact detection system|
|WO1998047436A1 *||Apr 24, 1998||Oct 29, 1998||Gyrus Medical Ltd||An electrosurgical instrument|
|WO2004028385A1||Sep 11, 2003||Apr 8, 2004||Fredricks Raymond A||Multiple rf return pad contact detection system|
|U.S. Classification||606/35, 330/8, 323/911, 606/38, 336/155|
|International Classification||A61B18/16, A61B5/0424, A61B18/12|
|Cooperative Classification||A61B18/1233, Y10S323/911, A61B5/0424, A61B18/16|
|European Classification||A61B5/0424, A61B18/12G6, A61B18/16|
|Sep 19, 1986||AS02||Assignment of assignor's interest|
Owner name: CASTLE COMPANY
Owner name: LIEBEL-FLARSHEIM COMPANY, A CORP. OF DE.
Effective date: 19860911
|Sep 19, 1986||AS||Assignment|
Owner name: CASTLE COMPANY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:LIEBEL-FLARSHEIM COMPANY, A CORP. OF DE.;REEL/FRAME:004610/0412
Effective date: 19860911
Owner name: CASTLE COMPANY, STATELESS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:LIEBEL-FLARSHEIM COMPANY, A CORP. OF DE.;REEL/FRAME:004610/0412
|Sep 15, 1986||AS02||Assignment of assignor's interest|
Owner name: LIEBEL-FLARSHEIM COMPANY, A CORP OF DE.
Owner name: SYBRON CORPORATION, A CORP OF NY.
Effective date: 19860731
|Sep 15, 1986||AS||Assignment|
Owner name: LIEBEL-FLARSHEIM COMPANY, A CORP OF DE.
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:SYBRON CORPORATION, A CORP OF NY.;REEL/FRAME:004624/0585
Effective date: 19860731