Abstract: A contact sensing assembly including a catheter including an electrode having a base portion mounted adjacent a head portion of the catheter body. A sensor is disposed adjacent the base portion for measuring compression or tensile forces applied to an electrode tip portion, and includes a predetermined sensitivity. The base and head portions include predetermined rigidity so that forces applied to the electrode tip portion are determinable as a function of the sensitivity and a sensor output. A contact sensing assembly also includes an electrode pipe operatively connected to the catheter body for movement and bending with the catheter body, and an electrode wire disposed in the electrode pipe and including insulation. A change in capacitance resulting from movement of the electrode wire toward the electrode pipe or contact of the electrode wire with the electrode pipe during bending of the catheter correlates to a force applied to the catheter.

Abstract: A method for determining a desired location at which to apply a neural therapy. An array of electrodes is positioned proximal to neural tissue. A stimulus is applied from the array which evokes a neural compound action potential response in the neural tissue proximal to the array. A plurality of electrodes of the array simultaneously obtain respective measurements of the neural compound action potential response. From the measurements of the neural compound action potential response a desired location for a neural therapy is determined.

Abstract: A suction apparatus evacuates the surgical smoke. For example, the suction apparatus may be arranged adjacent to an electrocautery electrode, which may generate smoke during operation, for evacuating smoke from a surgical site. The suction apparatus may have a ring manifold having an inner perimeter for receiving the surgical instrument. A plurality of suction intake ports may be arranged about the outer perimeter of the ring manifold for evacuating smoke that may be generated by the surgical instrument.

Abstract: Embodiments of the present disclosure include a method for treating tissue. The method may include delivering a medical device through a channel of an endoscopic device, wherein the medical device may include an elongate member, a cap coupled to a distal end of the elongate member and having a cavity, and an electrically-conductive tool extending into the cavity of the cap. The method may also include extending a portion of the medical device out of the channel of the endoscopic device and to the tissue, drawing a portion of the tissue into the cavity of the cap, electrically activating the tool to pierce the portion of the tissue, and cutting the tissue by moving the medical device along a plane of the tissue.

Abstract: A method includes assessing tumor margins and discriminating between tumor and non-tumor tissues by analyzing the compositional make-up of smoke produced during cautery resection of tissues.

Abstract: An electrode assembly is provided. The electrode assembly includes a proximal end that is adapted to connect to an electrosurgical instrument including a housing defining a longitudinal axis therethrough and an electrosurgical energy source. A distal end includes a cutting electrode having a loop configuration configured to cut tissue. The distal end includes a return electrode operably disposed adjacent the cutting electrode. A dielectric shield is operably disposed between the cutting electrode and return electrode. The dielectric shield extending distally past the cutting electrode to hinder current flow to the return electrode when the dielectric shield, cutting electrode and return electrode are submersed in a conductive solution and the cutting electrode is energized, thereby concentrating current density at the cutting electrode.

Abstract: In a high-frequency knife, a through hole that extends in the direction of an axis is formed on a radial outer side of a second electrode in a larger-diameter portion, and a distance increasing portion increases a creeping distance along an external surface of the larger-diameter portion between an outer peripheral surface of the second electrode exposed to the outside and an opening of the through hole on a proximal end side.

Abstract: An improved electrosurgical scalpel, with light emission, for generating electrical signals intended for applications to the body of a patient via an electrosurgical electrode is provided. An electrosurgical scalpel includes a handle with a receptacle portion of a conductive member for mounting and retaining an electrode blade, a light source with a power source encapsulated within the handle and a means to direct the light emitted outwardly towards the electrode tip. Operation of a switch on the handle to an on position serves to complete a circuit, activating the light source and, thereby directing light through an opening or upper portion and out from the first end of the handle towards the distal end of the electrode blade.

Abstract: A high frequency electrosurgical power generator configured to produce electrical power at a frequency of about 1 to about 14 MHz and preferably having an essentially sinusoidal waveform with a voltage level up to 1,000 Vrms, and a current level up to 5 Amps. The output of the high frequency electrosurgical power generator is connected to an electrosurgical tool configured to receive the voltage and current produced by the electrosurgical power generator and deliver the voltage and current to an electrosurgical site. The output of the electrosurgical generator preferably is an essentially sinusoid waveform with a frequency between about 3 MHz and about 8 MHz, up to about 700 volts rms, up to about 2 amps, with a total power of up to 1,000 watts.

Abstract: Methods and devices that displace bone or other hard tissue to create a cavity in the tissue. Where such methods and devices rely on a driving mechanism for providing moving of the device to form a profile that improves displacement of the tissue. These methods and devices also allow for creating a path or cavity in bone for insertion of bone cement or other filler to treat a fracture or other condition in the bone. The features relating to the methods and devices described herein can be applied in any region of bone or hard tissue where the tissue or bone is displaced to define a bore or cavity instead of being extracted from the body such as during a drilling or ablation procedure.

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: The present disclosure relates to an end effector assembly for use with an electrosurgical instrument. The end effector assembly includes a pair of opposing first and second jaw members and a first electrically conductive cutting plate. The pair of opposing first and second jaw members is movable to cooperatively grasp tissue. Each of the jaw members includes a tissue contacting plate that is disposed thereon and has a longitudinal channel that is defined therealong. The first electrically conductive cutting plate includes a cutting element that extends along the first electrically conductive cutting plate and into the longitudinal channel of the first jaw member to engage and electrosurgically sever tissue upon activation thereof.

Abstract: An electrosurgical system is disclosed. The system includes an electrosurgical generator adapted to supply electrosurgical power and an electrosurgical device coupled to the electrosurgical generator. The electrosurgical device includes a transformer and one or more active electrodes coupled thereto, wherein the transformer is adapted to step down the voltage of the power supplied by the electrosurgical generator.

Abstract: An elongated electrosurgical instrument (1) serves to at least cutting tissue of a patient during surgery by application of electrical energy supplied from an electrosurgical generator to a surgical site. The electrosurgical instrument has a hollow elongated main body (2) with an electrode means (3). Suction means comprises a suction channel (27) extending inside the hollow elongated main body (2), a first suction port (40) arranged facing the first means (3), a second suction port (41) provided with a suction tubing (11) in communication with the vacuum source, and a suction tip (6). The suction tip (6) has a coupling end part (76) that has a first engagement means (78) for engagement with a second engagement (25) means provided on the hollow elongated main body (2).

Abstract: Tissue may be cut and extracted from an interior location in a patient's body using a probe or tool which both effects cutting and causes vaporization of a liquid or other fluid to propel the cut tissue through an extraction lumen of the cutting device. The cutting may be achieved using an electrosurgical electrode assembly, including a first electrode on a cutting member and a second electrode within a cutting probe or tool. Thus, over a first cutting portion, radio frequency current may help cut the tissue and over a second or over transition region, the RF current may initiate vaporization of the fluid or other liquid to propel the tissue from the cutting device.

Abstract: An endoscopic incision system includes: an endoscope; a cylindrical member for covering at least a distal end of an insertion section of the endoscope; and at least an incision section for incising a living tissue, the incision section being provided to a distal end of the cylindrical member and being capable of being exposed from the distal end of the cylindrical member outwardly. In this configuration, the radially expanding incision section will not be twisted or bent, and the incision section prevented from inadvertent fall-off can maintain the desirable shape when it is operated and rotated.

Abstract: Electrosurgical devices including a shaft, a handle and a distal end portion. The distal end portion is formed of an electrically conductive material and includes an electrically insulating material covering a substantial portion of the distal end portion and leaving an exposed portion which acts as an active electrode for delivery of electrical energy to tissue. A conduit in the shaft extending to an opening in the distal end portion facilitates aspiration of tissue and may provide suction simultaneous with delivery of electrical energy. Systems include an electrosurgical device, a source of electrical energy and may optionally include a source of suction and/or a source of fluid delivery or irrigation.

Abstract: A system and tool for performing a capsulotomy procedure. The system includes a capsulotomy and movement control unit providing electrical current and movement control, and a capsulotomy tool, and an extendable-retractable burning element coupled to the tool, and a slidable shaping element. A capsulotomy and movement control unit provides electrical current to the burning element and movement control for extending and retracting the burning element. When the burning element is in a flattened, retracted configuration, the tip of the tool can be inserted through a relatively small corneal incision. Then, the burning element is opened to a full circular, extended configuration, by pressing the shaping element against both joints of the bands, allowing a capsulotomy by applying an electrical pulse to the burning element.

Abstract: In one general aspect, various embodiments are directed to a surgical instrument that can supply mechanical energy and electrical energy to an end effector of the surgical instrument. The surgical instrument may be operated in a first operating mode in which a transducer of the surgical instrument produces mechanical energy, or vibrations, that are transmitted to the end effector and a second operating mode in which electrical energy, or current, can flow through the end effector to perform electrosurgery. In another general aspect, the surgical instrument may comprise a clamp, or jaw, which can be moved into a closed position to hold tissue against a waveguide, or blade, of the end effector. In the second operating mode of the surgical instrument, current can flow from a power source, through the waveguide, and return to the power source through a path comprising the jaw.

Abstract: The invention relates to an HF surgical instrument for treating, in particular for cutting and coagulating, biological tissue by means of an HF current. The HF surgical instrument comprises an HF generator for supplying an HF current to a cutting electrode and at least one control device for interrupting an HF current circuit. The control device comprises a current monitoring device, which detects the amplitude of the HF current and then generates a first switch-off signal when the HF current decreases over a defined period of time and/or the HF current falls below a threshold value characterizing a state of the treated tissue, as well as an arc monitoring device, which generates a second switch-off signal when an arc is formed between the cutting electrode and the tissue. The control device is configured in such a way that the HF current circuit is interrupted in response to the first switch-off signal or the second switch-off signal.

Abstract: An electrosurgical generator is disclosed. The generator includes an output stage configured to generate a waveform, a first input configured to adjust a cut setting representative of a cutting effect of the waveform, and a second input configured to adjust a hemostasis setting representative of a hemostasis effect of the waveform. The generator also includes a controller configured to receive cut and hemostasis settings and to adjust one of a duty cycle, a crest factor and a power level of the waveform to achieve a combined cutting and hemostasis effect based on the cut and hemostasis settings.

Abstract: A method for controlling an electrosurgical generator is contemplated by the present disclosure. The method includes applying an electrosurgical waveform to tissue through an electrode. The electrosurgical waveform includes one or more positive half-cycles one or more negative half-cycles. The method also includes measuring voltage and current of the electrosurgical waveform to detect a peak voltage of each of the positive half-cycles and the negative half-cycles and comparing the peak voltage of the positive half-cycles and the peak voltage of the negative half-cycles to determine generation of electrical discharges. The method further includes adjusting the current of the electrosurgical waveform to regulate the generation of the electrical discharges based on a comparison of the peak voltage of the positive half-cycles and the peak voltage of the negative half-cycles.

Abstract: An electrosurgical device and system including a blade operatively coupled to an energy source is disclosed herein. The electrosurgical device includes an optical sensor to monitor physical characteristics of the blade such that the device may automatically regulate the energy supplied to the blade and/or the operator may adjust several parameters including how the blade is removed and how much energy is supplied to the blade. A method of using the device and system is also disclosed.

Abstract: An interventional device (12) is configured to be positioned in a body and includes an electrically operable unit (E1, E2) configured to carry out an interaction with the body upon a receipt of electric power. The device further includes a sensor (2) configured for wirelessly receiving electromagnetic energy from a remote source. The sensor is configured as a resonant circuit (2a, 2b) which converts the received electromagnetic energy into the electric power. The electrically operable device may include a diagnostic and/or therapeutic module.

Abstract: A medical fluid filter system is provided having a housing having: a liquid trap chamber having a volume; a filter media chamber; a filter media arranged within the filter media chamber; the liquid trap chamber having a liquid trap outlet port in fluid communication with the filter media chamber; the liquid trap outlet port configured and arranged within the liquid trap chamber to inhibit flow of liquid from the liquid trap chamber to the filter media chamber and configured and arranged to allow gas to flow from the liquid trap chamber to the filter media chamber; a filter system inlet passing through the housing for intake of fluid originating from a surgical site; and a filter system outlet passing through the housing for fluid exhaust.

Abstract: Devices, systems and methods for cutting and sealing of tissue such as bone and soft tissue. Devices, systems and methods include delivery of energy including bipolar radiofrequency energy for sealing tissue which may be concurrent with delivery of fluid to a targeted tissue site. Devices include debridement devices which may include a fluid source. Devices include inner and outer shafts coaxially maintained and having cutters for debridement of tissue. An inner shaft may include electrodes apart from the cutter to minimize trauma to tissue during sealing or hemostasis. Devices may include a single, thin liner or sheath for electrically isolating the inner and outer shafts.

Abstract: A method and apparatus include determining a value of a parameter associated with operation of an electrosurgical probe having a particular probe design, and determining whether the value of the parameter is within a range of values that has been predetermined for the particular probe design to indicate that the probe is treating tissue in a desired manner. Power is delivered to the probe according to an algorithm based upon a determination that the value of the parameter is outside the range of values The algorithm delivers power in a pulsed profile including portions of low power and portions of high power. In one embodiment, the tissue treatment is ablation, the parameter is impedance, and the method limits tissue necrosis to less than 200 microns. In another embodiment, the tissue treatment is shrinkage, the parameter is temperature, and the method limits power delivery when the probe is not shrinking tissue.

Abstract: Adjacent tissue layers can be accessed using a catheter device with a distal tip having a conductive portion including a first cutting feature and one or more projections extending from the first cutting feature towards an outer diameter of the distal tip. Electrical energy can be supplied to the conductive portion of the device to cut tissue. A stent can be delivered to form a fluid communication between the adjacent tissue layers.

Abstract: Tissue may be cut and extracted from an interior location in a patient's body using a probe or tool which both effects cutting and causes vaporization of a liquid or other fluid to propel the cut tissue through an extraction lumen of the cutting device. The cutting may be achieved using an electrosurgical electrode assembly, including a first electrode on a cutting member and a second electrode within a cutting probe or tool.

Abstract: A medical instrument for an endoscope according to the invention is the medical instrument to be used in the endoscope by being inserted therein, and the medical instrument includes: a flexible elongated sheath having a first lumen and a second lumen; a conductive wire which is inserted into the first lumen and of which a portion of a distal side is exposed to the outside of the sheath as an instrument unit; and a balloon which is attached to the sheath and is expandable with the supply of fluid from the second lumen. The balloon is configured such that an axial dimension thereof is larger than a radial dimension upon expansion and a distal end of the balloon upon expansion is located closer to a proximal side than the treatment unit exposed from the sheath.

Abstract: A method of making an incision in an organ includes piercing, by a puncture needle having a proximal end and a distal end, an abdominal wall and an organ that is to be incised, disposing, via the puncture needle, an electrode, to which a first end of a cable is electrically connected, inside the organ, and disposing a second end of the cable outside a body, performing insufflation using a conduit so as to form a space between the abdominal wall and the organ, pulling the cable farther from the second end so that the electrode is placed in contact with an incision position of the organ, and the incision position of the organ is pulled into the space, and supplying power to the cable so that an incision is made by the electrode at the incision position of the organ.

Abstract: A multi-mode electrosurgical apparatus for use in cold plasma applications, electrosurgical cutting, electrosurgical coagulation and mechanical cutting is provided. The electrosurgical apparatus includes a housing having a passage extending therethough, an electrically conducting tube being disposed in the passage of the housing; an insulating outer tube disposed around the electrically conducting tube coupled to the housing, the electrically conducting tube being movable along a longitudal axis of the housing and outer tube; an electrically conducting blade coupled to the distal end of the electrically conducting tube, and a transformer assembly disposed on a proximal end of the housing, the transformer assembly including a first transformer and a first switch for selectively coupling the first transformer and an external second transformer to the electrically conducting tube for providing electrosurgical energy thereto.

Abstract: An electrosurgical cutting device and method thereof for incising tissue are disclosed. The electrosurgical cutting device includes an asymmetrical cutting element that is affixed to a distal end of a torque cable. The cutting element is disposed within an end cap and is axially movable between a retracted position and an extended position. Rotation of the torque cable during a procedure allows the cutting element to rotationally align with and hook the target tissue onto the cutting element. An elongate member of the cutting element selectively lifts the target tissue away from surrounding tissue and structures. Having lifted the tissue away the surrounding tissue and structures, incision can occur.

Abstract: Tissue may be cut and extracted from an interior location in a patient's body using a probe or tool which both effects cutting and causes vaporization of a liquid or other fluid to propel the cut tissue through an extraction lumen of the cutting device. The cutting may be achieved using an electrosurgical electrode assembly, including a first electrode on a cutting member and a second electrode within a cutting probe or tool. Thus, over a first cutting portion, radio frequency current may help cut the tissue and over a second or over transition region, the RF current may initiate vaporization of the fluid or other liquid to propel the tissue from the cutting device.

Abstract: Thermal, electrosurgical and mechanical modalities may be combined in a surgical tool. Potentially damaging effects in a first modality may be minimized by using a secondary modality. In one example, thermal hemostasis may thus help electrosurgical applications avoid the adverse tissue effects associated with hemostatic monopolar electrosurgical waveforms while retaining the benefits of using monopolar incising waveforms.

Abstract: A method for mitigating leakage in an RF electrosurgical generator includes delivering an RF signal from an RF electrosurgical generator to an electrosurgical electrode by way of a patient box; providing a balanced and symmetrical shielded transmission line coupling said electrosurgical generator disposed in a first housing to said patient box disposed in a second, different housing; providing a common mode choke in said patient box, said common mode choke including an output winding and a return winding, said output winding and said return winding spaced apart and in parallel to maintain a desired impedance, said output winding comprising a wire carrying said RF signal as an output signal and said return winding carrying a return signal from a return electrode; and directing a common mode signal from said RF signal to said common mode choke thereby blocking said common mode signal.

Abstract: A surgical instrument for performing water jet surgical operations comprises a nozzle that can be moved via a hydraulic actuator out of a retracted or passive position into a moved-forward or active position. The actuation is accomplished using hydraulic fluid that is supplied to the instrument head via a tube and/or hose. The fluid (e.g., a sodium chloride solution) that is to be injected into the tissue can be used as the hydraulic fluid that is supplied to the nozzle. High-frequency (HF) current can additionally be applied to the nozzle. The HF current can be conducted to the nozzle via a line extending through the fluid conducting element or via the electrolyte present therein.

Abstract: The present invention relates to a plasma-generating device comprising an anode, a cathode, and intermediate electrodes. The intermediate electrodes and the anode form an elongate plasma channel that extends from a point between the cathode and the anode and through the anode. The plasma channel has a throttling portion with a throat having the smallest cross-sectional area of the entire plasma channel. As a plasma flow passes through the throttling portion, the plasma flow's speed is increased while its pressure is decreased. By varying the position of the throttling portion in the plasma channel properties of the discharged plasma can be changed. Plasma flows with different properties can be used for various applications, especially, medical procedures.

Abstract: A series of tips for use with an ultrasonic or piezoelectric dental surgical device dental are used in osteotomy, ostectomy and osteoplasty procedures or any procedure requiring removal or shaping of bone or other hard tissues. In some embodiments, fissures are provided in a cutting end of the tip to facilitate osteotomy. The tips are shaped so that they are comfortable for the surgeon to use in a proper position, so that when a handpiece to which the tips are releasably attached is held in the conventional manner, the geometry of the osteotomy will be precise and desirable. When energized, the tips readily cut through bone or facilitate shaping of skeletal structures at the surgical site. Methods for use of the tips and systems in which the tips provided the cutting function are also described.

Abstract: An electrosurgical generator includes one or more radio frequency (RF) power sources and an output stage including at least two output lines for connection to an electrosurgical instrument. The generator includes means for measuring a parameter associated with the electrosurgical procedure, such as the impedance measured across two of the output lines. A controller controls the generator such that it delivers a first RF waveform (such as a cutting signal) or a second RF waveform (such as a coagulating signal) to the output lines, and, in a combined mode, both first and second waveforms. The controller automatically adjusts at least one aspect of one or both waveforms in the combined mode, in response to the measured parameter associated with the surgical procedure.

Abstract: An electrical conductor, such as a wire or catheter, which is coated circumferentially with a ferromagnetic material in a selected region, is fed from a high frequency alternating current source. The ferromagnetic material has a quick response in heating and cooling to the controllable power delivery. The ferromagnetic material can be used for separating tissue, coagulation, tissue destruction or achieving other desired tissue effects in numerous surgical procedures.

Abstract: The subject invention is a surgical scalpel, scalpel instrument and/or scalpel system (collectively, scalpel), particularly designed for use in a transverse carpal ligament surgical procedure, that evaluates an incision path with respect to a nerve in the incision path, and is used to perform the incision if appropriate. The scalpel emits an evaluation signal through a potential incision path through tissue captured by the scalpel. The scalpel utilizes the emitted evaluation signal to determine the presence of a nerve in the incision path. The dissection and evaluation (surgical) instrument includes a blade that is retractable relative to a target tissue capture area thereof. Evaluation may include determining the presence of a nerve before incision and/or the evaluating whether the target tissue has been appropriately captured.

Abstract: An electrical conductor, such as a wire or catheter, which is coated circumferentially with a ferromagnetic material in a selected region, is fed from a high frequency alternating current source. The ferromagnetic material has a quick response in heating and cooling to the controllable power delivery. The ferromagnetic material can be used for separating tissue, coagulation, tissue destruction or achieving other desired tissue effects in numerous surgical procedures.

Abstract: Thermal, electrosurgical and mechanical modalities may be combined in a surgical tool. Potentially damaging effects in a first modality may be minimized by using a secondary modality. In one example, thermal hemostasis may thus help electrosurgical applications avoid the adverse tissue effects associated with hemostatic monopolar electrosurgical waveforms while retaining the benefits of using monopolar incising waveforms.

Abstract: The device includes an elongate shaft having a distal end coupled to a proximal end of an articulation joint, and an actuation wire extending through the elongate shaft and the articulation joint. The device includes an end effector having a distal tip coupled to a distal end of the articulation joint and receiving therethrough a distal end of the actuation wire. The end effector includes a hook knife disposed adjacent the distal tip and having a proximal end connected to the distal end of the actuation wire. The actuation wire is translatable along a longitudinal axis of the elongate shaft to extend and retract the distal end of the hook knife relative to the distal tip of the end effector, and the articulation joint is laterally articulatable relative to the longitudinal axis of the elongate shaft to allow the end effector to be angularly oriented relative to the elongate shaft.

Abstract: An electrical conductor, such as a wire or catheter, which is coated circumferentially with a ferromagnetic material in a selected region, is fed from a high frequency alternating current source. The ferromagnetic material has a quick response in heating and cooling to the controllable power delivery. The ferromagnetic material can be used for separating tissue, coagulation, tissue destruction or achieving other desired tissue effects in numerous surgical procedures.

Abstract: Thermal, electrosurgical and mechanical modalities may be combined in a surgical tool. Potentially damaging effects in a first modality may be minimized by using a secondary modality. In one example, thermal hemostasis may thus help electrosurgical applications avoid the adverse tissue effects associated with hemostatic monopolar electrosurgical waveforms while retaining the benefits of using monopolar incising waveforms.

Abstract: A method for performing an electrosurgical procedure is presented including providing an electrosurgical system having an electrosurgical generator, a first electrosurgical device including a first electrically conductive element, a second electrosurgical device including a second electrically conductive element configured to be coupled to a first location of a target tissue and a third electrosurgical device including a third electrically conductive element configured to be coupled to a second location of the target tissue. The method also includes the steps of positioning the second and third electrically conductive elements relative to one another, orienting and defining a direction and a length of a single resection line between the second and third electrically conductive elements, and moving the first electrically conductive element along the single resection line to desiccate or divide the target tissue.

Abstract: A catheter and catheter system can use energy tailored for remodeling and/or removal of target material along a body lumen, often of atherosclerotic material of a blood vessel of a patient. An elongate flexible catheter body with a radially expandable structure may have a plurality of electrodes or other electrosurgical energy delivery surfaces to radially engage atherosclerotic material when the structure expands. An atherosclerotic material detector system may measure and/or characterize the atherosclerotic material and its location, optionally using impedance monitoring.

Abstract: A method and apparatus include determining a value of a parameter associated with operation of an electrosurgical probe having a particular probe design, and determining whether the value of the parameter is within a range of values that has been predetermined for the particular probe design to indicate that the probe is treating tissue in a desired manner. Power is delivered to the probe according to an algorithm based upon a determination that the value of the parameter is outside the range of values The algorithm delivers power in a pulsed profile including portions of low power and portions of high power. In one embodiment, the tissue treatment is ablation, the parameter is impedance, and the method limits tissue necrosis to less than 200 microns. In another embodiment, the tissue treatment is shrinkage, the parameter is temperature, and the method limits power delivery when the probe is not shrinking tissue.