Abstract: A surgical safety apparatus for use in connection with an energizable surgical device minimizes inadvertent activation of a surgical tool when the oxygen or flammable gas level is too high. An activation circuit is connected with an energy source and with a hand piece of the tool. A sensor measures the oxygen or flammable gas near the tool and can operate in a first state to disconnect the energy source from the hand piece. In a second state the source of energy is connected to the hand piece. The sensing element is connected to the activation circuit. The sensing element signals the activation circuit to convert the activation circuit from the first state to the second state provided the oxygen or flammable gas level is safe.

Abstract: Methods and apparatus for selectively heating a target tissue via radiofrequency (RF) electrical energy. Apparatus of the invention includes an electrode unit having a plurality of concentric electrodes, wherein supply of electrical energy to each electrode may be independently controlled such that each of the plurality of electrodes has a different value of an electrical parameter for tissue treatment. Methods for selectively heating and treating tissue, for detecting thickness of tissue, and for determining a treatment value of an electrical parameter for each of a plurality of electrodes of an electrode unit are also disclosed.

Abstract: A radio frequency tissue ablation system with a radio frequency generator, the generator comprising a radio frequency source, at least four independently controllable radio frequency outputs, a user interface and a controller configured to delivery radio frequency energy from the radio frequency source to the radio frequency outputs in one of at least two different output configurations in response to a configuration selection made through the user.

Abstract: An apparatus for protecting a nontarget body tissue of a patient during electrocautery surgery, an electrocautery probe being adapted to provide an electrical field to electrocauterize a target body tissue of the patient, includes a stent. The stent is adapted to detect the electrical field and to produce a field proximity signal in response to the detected electrical field. An electrical source provides electrical power to the probe. An electrical controller is adapted to receive the field proximity signal and to regulate electrical power to the probe in response to the field proximity signal. A method for protecting a nontarget body tissue of the patient during electrocautery surgery is also described.

Abstract: An OTC surgical device includes a handle having therein a compression controller and thereat an end effector, which has an electrically controlled tissue-compressor coupled to the controller and powered thereby to selectively control tissue compression. A mechanical binary-output electrical switch is disposed in-line with the compressor to place a compressing force directed upon the compressed tissue proportionally upon the switch. The switch has two switching states initiated and changed only by mechanical movement. The switch includes a biasing device retaining the switch in a first switching state until a force imparted thereupon overcomes the bias force to change to the second switching state. A switching-state-status output provides information identifying a current state and communicates with the compression controller to selectively control compression of tissue based upon the information. With appropriate feedback, the controller can keep the tissue at OTC while the surgical procedure is carried out.

Abstract: This relates to a device for treating lung disease, and more particularly, relates to a device for exchanging energy with airway tissue such as that found in the airways of human lungs. The exchange of energy with this airway tissue in the airways reduces the ability of the airways to constrict and/or reduces the resistance within the airway to the flow of air through the airway.

Abstract: An electrical lead including a conductor assembly, an electrode, and a thermally sensitive material. The conductor assembly has one or more conductors. The electrode is in electrical communication with one of the conductors and has an outer contact adapted for contacting adjacent body tissue of a patient. The thermally sensitive material is electrically connected between the one conductor and the electrode outer contact, and is configured to exhibit high impedance in the presence of currents considered unsafe to the patient, thereby preventing the unsafe currents from flowing through the thermally sensitive material and through the electrode outer contact potentially causing the adjacent body tissue to increase in temperature to an unsafe level. The unsafe currents cause the thermally sensitive material to increase in temperature, thereby causing the material to transition to a high impedance state.

Abstract: The invention relates to an electrosurgical instrument for coagulating and/or cutting biological tissue, which can be manufactured easily and economically, wherein a surgical intervention is to be carried out easily and reliably with the instrument.

Abstract: An apparatus for treating tumors comprises an elongated delivery device that includes a lumen and is maneuverable in tissue. An impedance sensor array is deployable from the elongated device and configured to be coupled to at least one of an energy source or a switching device. The impedance array includes a plurality of resilient members, at least one of the plurality being positionable in the elongated device in a compacted state and deployable with curvature into tissue from the elongated device in a deployed state. In the deployed state, the plurality of resilient members defines a sample volume. At least one of the resilient members includes an impedance sensor and at least a portion of the array is configured to sample tissue impedance through a plurality of conductive pathways. An energy delivery device is coupled to one of the array, the at least one resilient member or the elongated device.

Abstract: Disclosed herein are high efficiency surgical devices and methods of using same using radio frequency (RF) electrical power and/or electrically heated filaments to destroy tumors, form lesions, denaturize, desiccate, coagulate and ablate soft tissues, as well as to drill, cut, resect and vaporize soft tissues. According to the principles of this invention, the electrosurgical instruments can be used with externally supplied conductive or non-conductive liquids, as well as without externally supplied liquids, a mode of operation often referred to as “dry field” environment.

Abstract: A method of electroforming tissue comprises creating stress in the tissue; and causing a direct current to flow in the tissue to change the stress, strain, or intrinsic mechanical properties including shape of the tissue. Force is mechanically applied to the tissue to create external stresses or material parameters of the tissue are used to create internal stresses in the tissue by causing a current to flow in the tissue. The method further comprises the step of monitoring the stresses in the tissue and controlling the current flowing in the tissue according to the stresses therein by monitoring impedance, the optical properties, the pH, acoustic properties of the tissue, the gas formation in the tissue, the color of the tissue as caused by a chemical dye disposed therein or as caused by electroplating a material thereon.

Abstract: Embodiments of the invention controlling power distribution in an ablation control apparatus or the like. In one embodiment, a power switching apparatus comprises a first switch assembly having an input end to receive a power input signal, the first switch assembly having a plurality of output channels; a second switch assembly coupled to the output channels of the first switch assembly; a plurality of power receiving members coupled to the second switch assembly; and a controller controlling the first switch assembly to selectively transmit the power input signal to the output channels one at a time in a cyclical manner according to a first switching rate.

Abstract: The invention is concerned with cauterizing and resecting tissue. A pair of electrodes are placed on opposed tissue surfaces, and radio frequency power is applied through the electrodes to cauterizing a tissue mass therebetween. After cauterization has been effected, the tissue may be resected along a plane within the cauterized region with minimum or no bleeding. The tissue mass may then be removed.

Abstract: An electrosurgical pencil (100) configured and adapted to support an electrocautery blade (116). A strain gauge (130) is affixed to the proximal, end of the electrocautery blade and measures the displacement of the blade as a result of resistance and drag acting on the blade. The electrosurgical pencil also includes a meter electrically connected to the strain gauge for monitoring either a change in voltage, a change in electrical current or a change in optical wavelength. The amount of blade displacement as measured by the strain gauge is available for display to the surgeon and/or as sensory input for a control circuit in the electrosurgical generator (118) that modulates the generator output waveform. The electrosurgical pencil further includes a control circuit electrically coupled between the electrocautery blade and the electrosurgical generator. The control circuit is configured and adapted to control power supplied to electrocautery blade based on the displacement measured by the strain gauge.

Abstract: The present invention discloses an electrode for radiofrequency tissue ablation which can coagulate and necrotize a tissue by radiofrequency electric energy. The electrode for radiofrequency tissue ablation precisely coagulates and necrotizes a target part of the tissue by sensing a temperature of the tissue.

Abstract: The invention is directed to a catheter that creates enhanced lesions using a needle electrode and can simultaneously map electrical activity at a plurality of points using an enhanced mapping assembly. The catheter comprises an elongated catheter body having at least one lumen extending longitudinally therethrough. A needle control handle is provided at the proximal end of the catheter body. A needle electrode assembly extends through the catheter body and needle control handle and has a proximal end attached to the needle control handle and a distal end within the distal end of the catheter body. A mapping assembly is mounted at the distal end of the catheter body and comprises at least two flexible spines. Each spine has a proximal end attached at the distal end of the catheter body and a free distal end. Each spine carries at least one electrode. The distal end of the needle electrode assembly is extendable past the proximal end of the mapping assembly upon manipulation of the needle control handle.

Abstract: A device for delivering energy to tissue, including an elongate flexible shaft having a proximal end and a distal end; at least one energy delivery device operably connected to the distal end of the shaft; a flange protruding from a tissue apposition surface of the energy delivery device; at least one thermocouple proximate said flange, whereby said flange is configured to pierce or displace tissue placed in abutment with the tissue apposition surface, and said thermocouple is configured to measure the temperature of the displaced or pierced tissue.

Abstract: An apparatus for delivering energy to tissue, comprising an elongate flexible shaft having a proximal end and a distal end; an first electrode operably connected to the elongate flexible shaft; and an second electrode operably connected to the elongate flexible shaft and electrically independent from the first electrode, said second electrode at least partially surrounding and spaced apart from the first electrode.

Abstract: Apparatus for forming a lesion in body tissue includes a probe having an active region with an electrode for contacting tissue to be treated, and an inactive region including an insulative sleeve around a portion of the electrode. The temperature of the inactive region is monitored using a temperature sensor. A controller supplies radio frequency energy to the electrode and samples signals from the temperature sensor. By performing a calculation using the sampled signals and a predetermined inactive region threshold temperature, and by adjusting the supplied radio frequency power, the inactive region of the probe can be maintained at or below an inactive region maximum temperature while the controller continues to supply radio frequency energy to the electrode. The probe has a second temperature sensor, mounted at a distal end of the electrode, the controller being configured to reduce the supplied radio frequency power when the electrode temperature reaches a predetermined maximum electrode temperature.

Abstract: A method for electrosurgically sealing a tissue includes steps of: (A) applying a first pulse of RF energy to the tissue; and (B) applying at least one subsequent RF energy pulse to the tissue and keeping constant or varying RF energy parameters of individual pulses of subsequent RF energy pulses in accordance with at least one characteristic of an electrical transient that occurs during the individual RF energy pulses. The method terminates the generation of the at least one subsequent RF pulse upon a determination that the electrical transient is absent.

Abstract: Method and system for adjusting the amount of energy delivered to a handpiece of a surgical system based on feedback. A table is generated that correlates differences between voltages and rates of change of a voltage of the output of a charging element of the surgical system. Charge values of the table, such as minimum and maximum charge rates, can be generated using profile pulses and the time that is required for a pulse to reach a predetermined voltage. Intermediate charge rates can be determined using interpolation or other suitable methods. The output of the charging element is monitored at a voltage source, such as a capacitor, to determine first and second voltages at different times. These voltages are reduced if necessary for compatibility with electronic components and converted into digital values. A difference between two digital values is determined, and the determined difference is used to determine a corresponding rate at which the charging element charges the voltage source.

Abstract: A surgical probe and methods for targeted treatment of structures of the heart with heat and radiofrequency energy. The probe which is designed to operated by hand has a elongate member with a handle and an energy-delivering member in an adjustable loop configuration. The control placed on the handle allow the user to alter the length of the loop configuration of the energy-delivering member and to thus place energy-delivering elements located on the energy-delivering member at selected or targeted portions of the heart or structures within the heart. The elongate member is conformable and can be bent into different configurations to allow additional targeted treatment of the particular portions of the heart.

Abstract: A control device for a medical system includes: an instructing unit, which can be instructed by an operator, for outputting an instructing signal according to the instruction by the operator; a control signal generating unit for receiving an instructing signal, and generating multiple control signals for controlling multiple medical apparatuses in accordance with the instructing signal; and multiple output units, which can be connected with a medical apparatus, for outputting control signals to the corresponding medical apparatus.

Abstract: A method and apparatus for carrying our thermal ablation of target tissue is disclosed. The apparatus includes an RF ablation device having a multi-electrode electrode assembly designed to be deployed in target tissue, defining a selected-volume tissue region to be ablated, and having infusion channels for infusing a liquid into the target tissue during the ablation process. A control unit in the apparatus is operably connected to an RF energy source, for controlling the RF power level supplied to the electrodes, and to an infusion device, for controlling the rate of infusion of a liquid through the device into the tissue. During both electrode deployment and tissue ablation, impedance and or temperature measurements made within the tissue are used to control the RF source and infusion device, for optimizing the time and extent of tissue ablation.

Abstract: Systems that measure temperatures of tissue during electrosurgery or laser therapy of the tissue or organs is provided. One system provides a pyrometer that measures infrared electromagnetic energy emitted by a surface of a tissue or organ thereby determining a sub-surface temperature of the tissue or organ. The system further has an energy generator and an ablation electrode or laser probe that delivers energy from the energy generator to a tissue or organ, responsive to a sub-surface temperature determined by the pyrometer. The pyrometer can be calibrated using a luminescent material having known optical properties as a function of temperature. The luminescent material can be positioned on the surface of the tissue or organ or inserted directly into the tissue or organ using a catheter. Methods in which the surface or sub-surface temperature of the tissue is measured during therapy are also provided.

Abstract: A cannula having a hollow metal tube for injection of liquids such as an anesthetic, or RF energy, into a patient. A thermocouple or other temperature sensor is located at the bare tip of the cannula, and a wire for the temperature sensor extends along the length of the cannula, preferably in a groove formed in the tube, or through a passageway formed in the tube. An outer insulation layer covers the tube and wire. Thus, a single device serves as both a cannula and an electrode.

Abstract: A resecting device is disclosed. The resecting device comprises: a handle having a jaw trigger slidably engaged with said handle and mechanically engaged with a spring mechanism communicating a biasing force to said jaw trigger; a fixed shaft portion having a first and a second end, wherein said fixed shaft portion first end is affixed to said housing, wherein said fixed shaft portion second end forms a first jaw member, and wherein said first jaw member has a tissue contact area; and a slidable shaft portion in communication with said spring mechanism and slidable relative to said fixed shaft portion.

Abstract: An electrosurgical bipolar instrument includes an instrument housing having a distal end, a proximal end and an elongated body therebetween. The electrosurgical bipolar instrument includes a pair of radio frequency (RF) electrodes disposed at the distal end of the instrument housing and a control circuit mounted within the instrument housing. The control circuit has a first cut/coagulate mode pad, a common pad and a first cut/coagulate mode push button configured to electrically couple the first cut/coagulate mode pad to the common pad when actuated. The electrosurgical bipolar instrument further includes a plug coupled to the proximal end of the instrument housing having first and second RF contacts electrically coupled to the pair of RF electrodes. The plug has a first cut/coagulate mode contact and a first common contact electrically isolated from the first and second RF contacts and the pair of RF electrodes.

Abstract: A device to visually indicate the presence of electric fields in electrosurgical apparatus, without the necessity of wiring or an electrical connection to the apparatus, to visually annunciate when an electrosurgical instrument is active is disclosed. This is to alert the operating surgeon, and observing personnel, that the device is operational to mitigate the possibility of anyone inadvertently being injured. The device is comprised of an electrically insulated enclosure filled with a gas in close proximity to a surgical handpiece connected to a radio frequency current generator.

Abstract: A method for electrosurgically sealing a tissue includes steps of: (A) applying a first pulse of RF energy to the tissue; and (B) applying at least one subsequent RF energy pulse to the tissue and keeping constant or varying RF energy parameters of individual pulses in accordance with at least one characteristic of an electrical transient that occurs during the individual RF energy pulses. The method terminates the generation of subsequent RF pulses upon a determination that the electrical transient has passed a predetermined limit.

Abstract: The electrode of a manipulator cuts tissue. The scalpel has rectifying circuit for supplying a rectified voltage to a radio frequency circuit which produces an output current signal at a substantially constant frequency to the electrode. The radio frequency circuit has an electronic switch controlled by an oscillator and pilot circuit. According to the method a wave form is applied to the electrode having such a power that the energy transferred to the manipulator is substantially equal to the sum of the energies required to break the bonds of the molecules of the tissue to be cut. The invention relates also to the electronic scalpel carrying out said method.

Abstract: A medical device for use by an operator to perform a medical procedure in a body includes a handle to be held by the operator, a shaft attached to the handle and an actuating assembly to control functions associated with the medical procedure. The shaft includes an operative distal portion to perform a medical procedure in the body. The medical device may be part of an ablation catheter system that is programmed to correlate one or more functions with the actuation of the actuating assembly. Multiple actuating assemblies may be provided. Each actuating assembly may be a button. Other types of actuating assemblies may also be used, such as switches or a trackball. The actuating assembly may also be provided on a sleeve that may be selectively attached to the handle of the catheter or the physician operating the catheter, for example.

Abstract: A system for heat ablation of tissue in a patient comprises a plurality of electrodes operatively connected to a source of radiofrequency energy and configured to apply RF energy to tissue at a patient site, a plurality of RF current restricting circuits, each circuit coupled between one of the plurality of electrodes and the source of radiofrequency energy, and configured to restrict RF energy to the electrode when the current restricting circuit is enabled and not restrict RF energy to flow to the electrode when the current restricting circuit is disabled, at least one return electrode adapted to contact the patient and configured to return RF energy to the RF source; and a switching mechanism configured to selectively enable each of the plurality of RF current restricting circuits, in one of a sequential and non sequential fashion, wherein the switching mechanism is isolated from each of the current restricting circuits.

Abstract: The invention is directed to a catheter that creates enhanced lesions using a needle electrode and can simultaneously map electrical activity at a plurality of points using an enhanced mapping assembly. The catheter comprises an elongated catheter body having at least one lumen extending longitudinally therethrough. A needle control handle is provided at the proximal end of the catheter body. A needle electrode assembly extends through the catheter body and needle control handle and has a proximal end attached to the needle control handle and a distal end within the distal end of the catheter body. A mapping assembly is mounted at the distal end of the catheter body and comprises at least two flexible spines. Each spine has a proximal end attached at the distal end of the catheter body and a free distal end. Each spine carries at least one electrode. The distal end of the needle electrode assembly is extendable past the proximal end of the mapping assembly upon manipulation of the needle control handle.

Abstract: A high efficiency electrosurgical ablator which is subjected to a combined oscillatory and mechanical debridement motion during resection of tissue is disclosed. The electrosurgical ablator is positioned in the proximity of the tissue to be treated in the presence of an electrically conductive fluid. A high frequency voltage is applied to the electrode of the ablator, and the electrode is subjected to an oscillatory or other repetitive motion created by an element located within the ablator assembly. The ablator electrode is further connected to a suction assembly that supplies suction from an external source.

Abstract: A method and system are disclosed for the mapping of energy delivery devices to energy sources. Energy capable of affecting a measurable property of the system is delivered through the energy delivery devices from the energy sources. A change in a property when the energy is delivered is measured using measuring devices that are associated in a known way with the energy delivery devices. A profile of the change is compared to a profile of the energy output in order to determine which energy sources produce an output capable of affecting the property measurable by each measuring device and, because of the association between measuring devices and energy delivery devices, each energy delivery device.

Abstract: A tissue-ablation method and apparatus are disclosed. The apparatus includes a plurality of RF ablation electrodes, and a plurality of sensor elements, each movable from retracted to deployed positions in a tissue to be ablated. A control device in the apparatus is operatively connected to the electrodes for supplying an RF power to the electrodes, to produce tissue ablation that advances from individual-electrode ablation regions to fill a combined-electrode ablation volume. The control device is operatively connected to the sensor elements for determining the extent of ablation in the regions of the sensor elements. The supply of RF power to the electrodes can thus be regulated to control the level and extent of tissue ablation throughout the combined-electrode volume. The electrodes are preferably hollow-needle electrodes through which liquid can be infused into the tissue, also under the control of the control unit, to modulate and optimize tissue ablation.

Abstract: Multi-phase RF ablation employing a two-dimensional or three-dimensional electrode array produces a multitude of currents paths on the surface of the ablation zone. This results in a uniform lesion with a size defined by the span of the electrode array. An orthogonal electrode catheter array suitable for cardiac ablation is used in conjunction with a two-phase RF power source to produce uniform square-shaped lesions of size 1.2 cm2. Lesions of larger size are created by successive adjacent placement of the square-shaped lesions. A temperature sensor at the electrode tip allows monitoring of ablation temperature and regulation of thereof to minimize the electrode tips from being fouled by coagulum. In another embodiment, an external auxiliary electrode is used in combination with the catheter electrodes. This also produces lesions of greater depth. In yet another embodiment, ablation is performed with a sequence of elementary electrode-electrical configurations.

Abstract: A closed-loop control system has a user interface for allowing a user to select at least one pre-surgical parameter. The system also has a sensor module for continually sensing at least one of electrical and physical properties proximate a surgical site and generating at least one signal and a control module for continually receiving the selected parameter from the user interface and the at least one signal from the sensor module. The system processes the signal in accordance with the parameter using at least one of a microprocessor, computer algorithm and a mapping. The control module generates a corresponding control signal relating to the signal from the sensor module, and provides the control signal to the generator. The control module has number of loop control modules with a first loop control module providing a ratio of a real time parameter value to a desired parameter value. The real time parameter value is from the signal from the sensor module.

Abstract: An electrosurgical method and apparatus comprises a probe, at least one temperature sensor, and a controller for generating and controlling electromagnetic energy supplied to the probe. The controller receives signals from the temperature sensor and controls the supply of electromagnetic energy such that the temperature of the probe is ramped up and then maintained at a steady state temperature of between 100° C. and 115° C. In an equilibration phase, between the ramping up and the steady state temperature, the controller holds the temperature of the probe substantially constant for a period of time to allow the temperature of different parts of the probe to equilibrate.

Abstract: Systems, methods, and instruments associated with controlling the operating modes of an electrosurgical instrument using control signals delivered in a wireless manner from the electrosurgical instrument to an electrosurgical generator. The electrosurgical instrument transmits wireless control signals to the electrosurgical generator to initiate delivery of electrosurgical energy. The control signals are delivered to the electrosurgical generator without the need for a conductive cord extending between the electrosurgical generator and the electrosurgical instrument. The energy is delivered to the electrosurgical instrument, in response to the wireless control signals, along a path through an electrode and the physician utilizing the electrosurgical instrument and/or a conductive path external to the physician. The electrode upon which the physician rests provides a path for the electrosurgical energy and optionally prevents burning of the physician during an electrosurgical procedure.

Abstract: An electrosurgical working end for automatic modulation of active Rf density in a targeted tissue volume. The working end of the probe of the present invention defines a tissue-engagement surface of an elastomeric material with conductive elements that extend therethrough. In one embodiment, the expansion of the elastomeric material can de-couple the conductive elements from an interior electrode based temperature to modulate current flow. In another embodiment, the elastomeric material can couple and de-couple the conductive elements from an interior electrode based engagement pressure to modulate current flow.

Abstract: Systems and methods employ a guide element that carries a region of energy emitting material. The systems and methods electronically couple the region to a source of energy that, when emitted by the region, ablates tissue. The systems and methods are responsive to user commands for changing the physical characteristics of the lesions being created by electronically altering the energy emitting characteristics of the region itself.

Abstract: Methods and apparatus are provided that prevent or inhibit functional regression caused by the stromal remodeling resulting from epithelial or fibroblastic apoptosis or necrosis in patients who will undergo or have undergone a thermal ciliary muscle tendinoplasty or scleral collagen shrinkage procedures. Methods and compositions are provided that prevent apoptosis in epithelial cells by stromal cooling during thermal tendinoplasty procedures; that create or restore stabilizing molecular cross-links between scleral stromal lamellar fibers; and that interrupt at least one step in the stromal remodeling response including inhibition of apoptosis, fibroblastic proliferation and migration, and inhibition of collagenesis.

Abstract: Technique for bonding soft biological tissue having an incision therein with forceps adapted to grip a portion of tissue on both sides of incision. Electrodes are secured to forceps for contracting the tissue portion. An electrical power source provides a high frequency electrical signal to electrodes to be passed through the tissue portion. The electrical power source is controlled to provide electrodes with one voltage signal during a first of two stages, wherein the voltage rises linearly, and another voltage signal during a second of the two stages, wherein the voltage is stabilized and modulated with a low frequency rectangular signal. A clamping means applies force with the forceps to compress the tissue at one or different levels during two time periods while the high frequency voltage is passed through the electrodes. The tissue impedance is measured as a function of time, with its minimal value being determined and stored.

Abstract: This invention is related to a tissue ablation system and method that treats atrial arrhythmia by ablating a circumferential region of tissue at a location where a pulmonary vein extends from an atrium. The system includes a circumferential ablation member with an ablation element and also includes a delivery assembly for delivering the ablation member to the location. The circumferential ablation member is generally adjustable between different configurations to allow both the delivery through a delivery sheath into the atrium and the ablative coupling between the ablation element and the circumferential region of tissue.

Abstract: An intelligent selection system for operating an electrosurgical instrument for use by a surgeon that depends primarily on the surgical procedure to be employed. The operating mode as well as other operating parameters can be controlled by the handpiece chosen by the surgeon to perform the procedure. Each handpiece is customized to activate when operated one of several preset operating modes of the electrosurgical instrument.

Abstract: A system and method for creating lesions and assessing their completeness or transmurality. Assessment of transmurality of a lesion is accomplished by monitoring the impedance of the tissue to be ablated. Rather than attempting to detect a desired drop or a desired increase impedance, completeness of a lesion is detected in response to the measured impedance remaining at a stable level for a desired period of time, referred to as an impedance plateau. The mechanism for determining transmurality of lesions adjacent individual electrodes or pairs may be used to deactivate individual electrodes or electrode pairs, when the lesions in tissue adjacent these individual electrodes or electrode pairs are complete, to create an essentially uniform lesion along the line of electrodes or electrode pairs, regardless of differences in tissue thickness adjacent the individual electrodes or electrode pairs.

Abstract: An electrosurgical generator has an output power control system that causes the impedance of tissue to rise and fall in a cyclic pattern until the tissue is desiccated. The advantage of the power control system is that thermal spread and charring are reduced. In addition, the power control system offers improved performance for electrosurgical vessel sealing and tissue welding. The output power is applied cyclically by a control system with tissue impedance feedback. The impedance of the tissue follows the cyclic pattern of the output power several times, depending on the state of the tissue, until the tissue becomes fully desiccated. High power is applied to cause the tissue to reach a high impedance, and then the power is reduced to allow the impedance to fall. Thermal energy is allowed to dissipate during the low power cycle. The control system is adaptive to tissue in the sense that output power is modulated in response to the impedance of the tissue.

Abstract: A flexible three-paths catheter provided with a balloon carries a sealingly sheathed radiofrequency radiating antenna, together with the shielded power supply cable and with some thermocouples, within a plastic lining surrounded by a flow of liquid; a second path carries the power supply cables of some outer thermocouples, flooded by the reverse liquid flow, while the third path allows a fluid to flow through for inflating the balloon. Introduction of the catheter into a hollow organ makes it possible to perform hyperthermal therapy of tumors by means of radiation.