Abstract: A magnetically topped catheter is used to tunnel into the myocardium for cardiac treatment.

Abstract: Method for carrying out the recovery of an intact volume of tissue wherein a delivery cannula tip is positioned in confronting adjacency with the volume of tissue to be recovered. The electrosurgical generator employed to form an arc at a capture component extending from the tip is configured having a resistance-power profile which permits recovery of the specimen without excessive thermal artifact while providing sufficient power to sustain a cutting arc. For the recovery procedure, a local anesthetic employing a diluent which exhibits a higher resistivity is utilized and the method for deploying the capture component involves an intermittent formation of a cutting arc with capture component actuation interspersed with pauses of duration effective to evacuate any accumulation or pockets of local anesthetic solution encountered by the cutting electrodes.

Abstract: Devices, systems, and methods are provided for accessing the interior of the heart and performing procedures therein while the heart is beating. In one embodiment, a tubular access device having an inner lumen is provided for positioning through a penetration in a muscular wall of the heart, the access device having a means for sealing within the penetration to inhibit leakage of blood through the penetration. The sealing means may comprise a balloon or flange on the access device, or a suture placed in the heart wall to gather the heart tissue against the access device. An obturator is removably positionable in the inner lumen of the access device, the obturator having a cutting means at its distal end for penetrating the muscular wall of the heart. The access device is preferably positioned through an intercostal space and through the muscular wall of the heart.

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: Disclosed is an electrosurgical generator that comprises a circuit and method to produce a filtering technique that utilizes the output transformer as the inductive element of the filter and places two capacitors on the output of the transformer to produce the desired filtering. The output filter configuration eliminates the use of power inductors and still creates the filtering required in electrosurgical applications. The filter utilizes the inductive properties of the output transformer along with several capacitors to form the bandpass filter.

Abstract: A surgical apparatus for removing a portion of tissue comprising an elongated body having a distal edge and a cutting member fixedly mounted to the elongated body and extending distally of the distal edge of the elongated body member. The cutting member has an exposed conductive distal edge forming an electrosurgical cutting surface for applying electrical energy to tissue. The cutting member resects a tubular region of tissue as the apparatus is advanced through tissue and the resected tissue extends through an opening in the cutting ring for containment within the elongated body.

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: Described is a high-frequency surgical instrument with automatic control of the intensity of the electric arcs between the active electrode and the tissue that is to be cut or coagulated, whereby for determination of the extent of the electric arcs, a therefrom dependent signal (K) is shunted off through a filter and conducted to a rectifier whose output signal is conducted to a variable-gain amplifier in which this output signal is compared either with the set-point signal (S) of a set-point device for the cutting process or with the set-point signal (K) of a set-point device for the coagulation process. The variable-gain amplifier generates a signal proportional to the difference of the signals E minus S or E minus K, respectively, which is conducted to an amplitude modulator which controls the amplitude of the output voltage of the power amplifier.

Abstract: A method and apparatus are provided for quickly connecting a handpiece to a pressurized fluid source. A hollow tube on the handpiece is inserted through an aperture in an annular gasket which is held in a chamber in a body. On application of pressurized fluid to the body, the gasket is pressed against the walls of the chamber, and against the tube, thereby channeling the pressurized fluid through the hollow tube. The handpiece is retained in connection with the body by a releasable connector, such as a latch. The handpiece can be removed and replaced by releasing and remaking the connection.

Abstract: An electrosurgical system includes a generator (10) for generating radio frequency power, and an electrosurgical instrument (12) including at least three electrodes. The generator comprises a radio frequency output stage having at least a pair of output lines (60C), and a power supply (66) coupled to the output stage for supplying power to the output stage. The generator also includes a controller (72) capable of varying a radio frequency signal supplied to the output lines, and a switching circuit (62) having three or more output connections (62A, 62B, 62C) each electrically connected with a respective one of the at least three electrodes. This switching circuit is operable to vary the connections between the output lines (60C) and the output connections (62A, 62B, 62C).

Abstract: A stainless steel electrosurgical blade has a single uniform layer of release material comprising substantially silicone (polysiloxane) applied directly onto the stainless steel blade portion without the necessity of one or more coatings of primer material(s), or multiple layering of the release material or mechanical roughening of the metallic blade body. Adherence of the release coating is achieved by thermally oxidizing the blade body, after cleaning it. The uniform layer is created by dipping the blade body. The release material is preferably thermally cured and non-blooming.

Abstract: Catheter apparatus for performing diagnostic and therapeutic modalities in the biliary tree includes a catheter with multiple lumens. A first lumen is adapted to receive a guidewire and can serve as a transport lumen for contrast agent. A second lumen carries a cutting wire for performing a sphincterotomy. A third lumen can be used as an inflation lumen for a distally located balloon. Expansion of the balloon occludes a portion of the biliary tree and allows the catheter to sweep any gallstones through the sphincter of Oddi into the duodenum.

Abstract: An electrosurgical apparatus comprises a high frequency generator (I) with an associated power control system, a handpiece (2) with means for removably mounting an electrode (5) therein, and a connection cable (3) between an output (4) of the generator and the handpiece. The transfer characteristic of the system provides a substantially true ohmic transfer of loads on the electrode side of the connection cable (3) to the generator side thereof at or around a predetermined load on the electrode.

Abstract: An electrosurgical working end and method for obtaining a tissue sample for biopsy purposes, for example, from a patient's lung or a liver. The working end provides curved jaw members that are positioned on opposing sides of the targeted anatomic structure. The working end carries a slidable extension member that is laterally flexible with inner surfaced that slide over the jaw members to clamp tissue therebetween. As the extension member advances, the jaws compress the tissue just ahead of the advancing extension member to allow the laterally-outward portion of the extension member to ramp over the tissue while a cutting element contemporaneously cuts the tissue. By this means, the transected tissue margin is captured under high compression. The working end carries a bi-polar electrode arrangement that engages the just-transected medial tissue layers as well as surface layers to provides Rf current flow for tissue welding purposes that is described as a medial-to-surface bi-polar approach.

Abstract: A catheter for ablating tissue comprises an elongated flexible catheter body having a continuous electrode comprising a braided conductive mesh surrounding a flexible plastic tubing. In a preferred embodiment, the catheter comprises a catheter body, a tip section at the distal end of the catheter body, and an electrode assembly at the distal end of the tip section. The electrode assembly comprises a flexible plastic tubing having an outer wall with a plurality of irrigation holes extending therethrough, a generally circular main region that is generally transverse to the axis of the catheter body, a continuous electrode formed of a braided conductive mesh surrounding the flexible plastic tubing and extending over substantially all of the generally circular main region, and a support member having shape memory extending within a lumen of the flexible plastic tubing. An electrode lead wire electrically connects the continuous electrode to a source of ablation energy.

Abstract: A surgical apparatus adapted to emit a plurality of high-energy inert gas atoms, such as argon, in a stream for cutting, cauterizing, or evaporating tissue. The apparatus comprises an inert gas supply, a plasma cell in communication with the inert gas source for imparting energy to the inert gas atoms and defined in part by a positive electrode and a negative electrode, at least one power supply electrically connected between the positive and negative electrodes, and means for directing the energized inert gas atoms at a target. The power supply provides initially an ionization voltage between the negative and positive electrodes to initiate a plasma from the inert gas in the plasma cell, and subsequently a pulsed voltage curve that sustains the plasma at a predetermined energy level. Methods for performing surgical procedures using the surgical apparatus for cutting, cauterizing, and/or evaporating portions of body tissue are also described.

Abstract: An ultrasonic dissection and coagulation system for surgical use is provided. The system includes an ultrasonic instrument, a control module, and a remote actuator. The ultrasonic instrument has a housing and an elongated body portion extending from the housing. An ultrasonic transducer supported within the housing is operatively connected to a cutting jaw by a vibration coupler. The vibration coupler conducts high frequency vibration from the ultrasonic transducer to the cutting jaw. The cutting jaw has a blade surface which is curved downwardly and outwardly in the distal direction with respect to the longitudinal axis of the elongated body portion along its length such that an angle defined by a line drawn tangent to the blade surface and the longitudinal axis of the elongated body portion varies between 5 degrees and 75 degrees.

Abstract: The invention realizes a radio knife powered by an electronic circuit that operates with high-frequency current wherein said circuit comprises: a rectifier circuit (20) fed by the mains voltage that supplies rectified pulsating voltage (201) to a radiofrequency circuit (30); a radiofrequency circuit (30) capable of emitting an output current signal (301) with a constant frequency in the scale of the MHz, powering the radio knife by means of a radiofrequency transformer (40). Said radiofrequency circuit (30) is obtained by piloting a MOSFET (305) through a pilot circuit (306) comprising a quartz-operated oscillator whose oscillation frequency amounts to at least twice the usual operating frequency of the MOSFET.

Abstract: An electrode device is for microwave coagulation therapy disclosed in which the direction of its electrode tip can be controlled by operation in its proximal region.

Abstract: An integrated catheter assembly for enabling diverse endoscopic in situ therapies. The assembly includes a catheter with an irrigation fluid lumen, a distal electrode tip portion that acts as a hemostat, and a cutting wire for making incisions in or ablating tissue. A cutting wire hub provides a sealing entrance for a cutting wire. An operator enables the physician to displace the cutting wire between extended and retracted positions. The cutting wire and electrode are electrically isolated. In addition, the catheter assembly may include a planar tip which, when extended outside the distal end of the assembly, assumes a substantially flat unbiased configuration for use. The apparatus of the present invention allows the physician to make incisions in or ablate tissue using electrosurgery, irrigate tissue, and cauterize or coagulate tissue without having to remove the apparatus from the working channel of the endoscope.

Abstract: The present invention relates to methods and devices for performing endoscopic cannulation, papillotomy and sphincterotomy and similar procedures. According to the present state of the art, endoscopic cannulation of the common bile duct and papillotomy and similar procedures are accomplished by advancing the device into an endoscope/duodenoscope so that the distal tip of the device exits the endoscope adjacent the sphincter muscles at the Papilla of Vater. The endoscope mechanisms are then manipulated to orient the distal tip of the device to the desired position for proper cannulation of the duct. Due to inconsistencies in, for example, the sphincterotome, anatomy, and endoscope manipulation, it is difficult to accurately and consistently position the sphincterotome for proper cannulation.

Abstract: An electrosurgical system including an electrode assembly having two electrodes for use immersed in an electrically conductive fluid has a generator with control circuitry for rapidly reducing the delivered radio frequency output power by at least 50% within at most a few cycles of the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam generation. The same peak voltage limitation technique is used in a tissue vaporization or cutting mode to limit the size of the steam pocket at the electrodes and to avoid electrode burning. In a blended mode, the output voltage is alternately limited to a value appropriate for coagulation and a value appropriate for cutting or vaporization.

Abstract: A heating treatment system consists mainly of coagulating/incising forceps in which a plurality of heating elements are incorporated, and a main unit that feeds power to the heating elements incorporated in the coagulating/incising forceps and that drives and controls the heating elements. The main unit can be connected to coagulating/incising forceps in which up to four heating elements are incorporated. The main unit includes element temperature measurement/output control units and temperature setting units which are associated with four channels allocated to the heating elements. A control unit controls the element temperature measurement/output control units and temperature setting units. The control unit judges the type of connected forceps by referencing data stored in advance in a memory using information of the type of forceps received from the coagulating/incising forceps, and controls power feed to the heating elements.

Abstract: A method of assessing the adequacy of contact between an ablation electrode and biological tissue within a biological organ having biological fluid therein includes the steps of positioning the ablation electrode proximal the biological tissue; positioning a reference electrode a distance from the ablation electrode; measuring the impedance between the ablation electrode and the reference electrode at a first frequency and measuring the impedance between the ablation electrode and the reference electrode at a second frequency. The percentage difference between the first-frequency impedance and the second-frequency impedance provides an indication of the state of electrode/tissue contact. In general, a percentage difference of at least approximately 10% serves as an indication of substantially complete electrode/tissue contact. A percentage difference in the approximate range between 5% and 10% serves as an indication of partial electrode/tissue contact.

Abstract: An arthroscopic probe with a distally orientated concave curve which constrains tissue is disclosed. It is particularly adapted to cutting ligaments and tendons. Also disclosed is a thermal energy delivery apparatus that includes (a) a probe with a distal end and a proximal end, (b) a first electrode positioned at the distal end of the probe and (c) a cabling coupled to the proximal end of the probe.

Abstract: An electrosurgical electrode comprises a generally L-shaped metal member comprising an electrically-insulated, generally straight shank part for mounting in a standard electrosurgical handpiece, and a generally curved part divided into first, second, third, and fourth sections, the second, third, and fourth of which are electrically-insulating and the first of which is bare and terminates in a pointed end. The second and third sections are covered with a thin electrically-insulating coating, whereas the fourth section, closest to the shank, is covered with a thicker electrically-insulating coating. The first, second, and third sections are dimensioned and constructed so as to enable the surgeon to know fairly precisely the depth of the first section in tissue targeted for radiofrequency thermal ablation. An important application is volumetric shrinkage of tongue base tissue, for example, for treating sleep disordered breathing.

Abstract: An electrosurgical system including an electrode assembly having two electrodes for use immersed in an electrically conductive fluid has a generator with control circuitry for rapidly reducing the delivered radio frequency output power by at least 50% within at most a few cycles of the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam generation. The same peak voltage limitation technique is used in a tissue vaporisation or cutting mode to limit the size of the steam pocket at the electrodes and to avoid electrode burning.

Abstract: An electrosurgical apparatus supplies high-frequency power from a high-frequency power supply unit to an instrument placed in association with an organic tissue to dissect or coagulate the organic tissue. An impedance calculating section calculates the impedance value of the organic tissue. A rate-of-impedance-change calculating section calculates the rate of impedance change of the organic tissue based on the impedance value calculated by the impedance calculating section. A control section controls the high-frequency output of the high-frequency power supply unit based on a predetermined condition provided by combining the impedance value calculated by the impedance calculating section with the rate of impedance change calculated by the rate-of-impedance-change calculating section.

Abstract: An electrosurgical system including an electrode assembly having two electrodes for use immersed in an electrically conductive fluid has a generator with control circuitry for rapidly reducing the delivered radio frequency output power by at least 50% within at most a few cycles of the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam generation. The same peak voltage limitation technique is used in a tissue vaporization or cutting mode to limit the size of the steam pocket at the electrodes and to avoid electrode burning. In a blended mode, the output voltage is alternately limited to a value appropriate for coagulation and a value appropriate for cutting or vaporization.

Abstract: An electrosurgery system for electrosurgically cutting or vaporising living tissue includes an electrosurgical generator having a pair of output terminals coupled to an electrosurgical instrument containing an electrode assembly. The electrode asssembly has at least one treatment electrode and an adjacent return electrode. The generator and the assembly are arranged to deliver to the treatment and return electrodes radio frequency (r.f.) energy individually or simultaneously at at least two frequencies, one of which is below 100 MHz and the other of which is above 300 MHz. The generator includes a load-responsive control circuit which, in one mode, causes power to be generated predominantly at the lower frequency when the load impedance is high and predominantly at the upper frequency when it is low. This allows automatic switching between cutting and coagulation operation. In another embodiment the r.f.

Abstract: A surgical apparatus for cutting a tissue mass comprising an elongated housing having a distal portion, a rotatable shaft positioned in the elongated housing, and a plurality of flexible electrocautery cutting blades extending from the housing, wherein the plurality of cutting blades are radially expandable from a first position defining a first diameter to a second larger diameter and the blades are rotatable and transmit electrical energy to cut the tissue mass.

Abstract: A medical device for treating the hemorrhoid, or reducing the dilatation of cellular tissues comprising ligating a hemorrhoid tissue and heating the hemorrhoid tissue. In one embodiment, an elongate tubular shaft comprises at least one coil loop electrode arrangement disposed at the distal end portion of the shaft, a RF energy generating source, and a method for deploying a dilated ligature element to effect the pressure therapy for the hemorrhoid tissues.

Abstract: An atherectomy device includes a catheter with a window at its distal tip for admitting tissue into a catheter compartment. A cylindrical cartridge in the compartment has a cutting edge that supports an electrically conductive cutting element, e.g. a band or wire. The cutting element and adjacent tissue can be heated to a selected temperature by generating an electrical current through the cutting element. The catheter is maneuverable to position its distal end near a lesion in an artery. The catheter incorporates a dilatation balloon or other feature to urge the catheter against the lesion, so that at least part of the lesion enters the compartment through the window. Then, the cartridge is manipulated from the catheter's proximal end to move the cutting edge across the window, severing the acquired tissue. According to alternative embodiments, the cartridge is either rotated or moved axially relative to the catheter, in either event closing the catheter window when the cut is complete.

Abstract: A bipolar medical instrument is provided for cutting tissue. The instrument comprises a first working element and at least one second working element, which are arranged adjacent to one another at a distal end of the instrument. The first working element and the second working element are configured as an electrode connectable to high frequency current and a counter electrode. One of the first working element and the second working element comprises at least one projection, which is directed toward the other working element. The free end of the projection is configured such that a concentration of the current density occurs at the free end.

Abstract: An electrosurgical system including an electrode assembly having two electrodes for use immersed in an electrically conductive fluid has a generator with control circuitry for rapidly reducing the delivered radio frequency output power by at least 50% within at most a few cycles of the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam generation. The same peak voltage limitation technique is used in a tissue vaporization or cutting mode to limit the size of the steam pocket at the electrodes and to avoid electrode burning.

Abstract: An electrosurgical system including an electrode assembly having two electrodes for use immersed in an electrically conductive fluid has a generator with control circuitry for rapidly reducing the delivered radio frequency output power by at least 50% within at most a few cycles of the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam Generation. The same peak voltage limitation technique is used in a tissue vaporisation or cutting mode to limit the size of the steam pocket at the electrodes and to avoid electrode burning.

Abstract: The invention features an assembly for taking a biopsy sample from a site within the body of a patient. The assembly includes a resecting device having a cutter near its distal end for resecting and containing a tissue sample and a sheath exterior to the resecting device and sized to be present within the body with the resecting device. The sheath includes an electrode element electrically isolated from the resecting device and disposed on the sheath's outer surface for cauterizing tissue. The resecting device and the sheath cooperate to permit sequential resecting of a tissue sample from a resecting site and cauterizing of the site with the cutter sufficiently spaced from the electrode element to avoid heat damage to the tissue sample.

Abstract: Low-power, low-voltage electrosurgical apparatus providing three current unipolar modes whose circuitry for generating the modulation signals needed to implement the three current modes employs no microcontroller but generates the modulation waveforms using a oscillator-binary counter and dual multiplexers, integrated components (ICs) that are of relatively low cost. Safety features can be incorporated by including a timer circuit cooperating with the binary counter to provide power to the IC components and avoid overheating of the apparatus. The oscillator-binary counter component is used to generate at plural outputs plural series of digital pulses at various frequencies, some of the pulse series being used to generate approximate sine-waves that can be employed for the cut/coag and hemo modes, and others of the pulse series being employed to operate a timer, indicator lights, and an audible warning system.

Abstract: An apparatus and method for igniting plasma in a surgical system is disclosed. A corona discharge is generated on a surgical handpiece which is used to ignite a plasma arc for surgical operations. The advantages include greater reliability and repeatability of plasma arc ignition. The apparatus comprises a handpiece incorporating an active electrode, a passage for ionizable gas, and a corona return electrode. The corona return electrode has a terminus on the holder and near the distal end of the holder. The corona return electrode is electrically connected to the return path of the electrosurgical generator. A non-uniform electric field is generated between the active electrode and the corona return electrode of sufficient strength so that a corona is formed near the active electrode. A separate return electrode may be on the patient, or the apparatus may be configured for bipolar electrosurgical operation by carrying the return electrode on the handpiece.

Abstract: An electrosurgical generator control responds to tissue impedance between active and return electrodes during desiccation. Active and return generator leads to supply energy and a user control sets the level of energy desired for electrosurgery. Voltage and current sensing circuits respond to high frequency energy in the leads to signal voltage and current in the leads. A multiplier receives the signals to calculate power. A clock sets units of time during for which power calculation. An integrator calculates the energy supplied through the leads per time unit. The user control sets a reference signal for the energy level desired. A correlation circuit receives the energy calculations from the integrator and the reference signal and provides a feedback signal to indicate when the energy calculation equals the user control setting for altering the generator supply of energy to the leads.

Abstract: An automatic circuit that controls a surgical instrument having a pair of bipolar electrodes. The circuit comprises means for measuring the current between the pair of electrodes, an impedance detection circuit in electrical communication with the current measuring means, a comparator in electrical communication with the impedance detection circuit and a controller electrically connected to the comparator. The impedance detection circuit calculates the impedance between the electrodes based on the measured current and generates a first signal indicative of the calculated impedance. The comparator processes the first signal and generates an activation signal if the calculated impedance falls within a predetermined range of impedance values and generates a deactivation signal if the calculated impedance exceeds a deactivation threshold.

Abstract: A puncture instrument capable of punctured high frequency treatments. The puncture instrument essentially includes: a guide tube to be inserted into an intracavitary portion of a patient; a puncture needle member having an elongated needle body slidably received in the guide tube, and a sharp-pointed needle head provided contiguously at the fore end of the elongated needle body and protrudable out of the guide tube to penetrate into a target intracorporeal portion to be treated when the needle body is manipulated in a forward direction; and a high frequency electrode provided on a fore end portion of the needle body to be penetrated into the target intracorporeal portion together with the sharp-pointed needle head.

Abstract: A handpiece is disclosed for a multifunctional instrument for endoscopic surgery. The handpiece comprises a case; a connector disposed on the case and adapted to be connected to connecting lines such as electrical lines, liquid supply and discharge lines, and the like; at least one ultrasonic transducer arranged in the case; an ultrasonic sonotrode transmitting the ultrasonic energy; and at least one switch for controlling functions of the handpiece. The handpiece is characterized by, among other things, the provision that the sonotrode includes a long and thin probe section with a duct composed of several segments which are welded to each other.

Abstract: Disclosed herein is a new arthroscopic probe with a concave distal tip which simultaneously constrains and cuts tissue. It is particularly adapted to cutting ligaments and tendons. Also disclosed is a thermal energy delivery apparatus which includes (a) a probe means with a distal end and a proximal end, wherein the distal end has a concave tip; (b) a first electrode means positioned at the distal end of the probe means, wherein the first electrode means is configured to deliver sufficient thermal energy to cut ligaments or tendons; and (c) a cabling means coupled to the proximal end of the probe means.In another embodiment of the invention a controller for controlling the delivery of energy and liquid to a surgical instrument with a temperature sensor is disclosed. The energy is supplied by an energy source and the liquid is supplied by a pump. The controller includes a temperature and a flow regulator. The temperature regulator is coupled to the energy source and coupled to the pump.

Abstract: A method for performing electrosurgery using sub-microsecond, high-power electrical pulses applied to an electrosurgical probe endface. The probe endface has an area of about 200-1000 microns.sup.2. The pulses have a duration less than 300 nanoseconds, and preferably have very fast risetimes and very fast falltimes (e.g. less than 100 nanoseconds). The pulses also have power dissipation greater than 500 Watts (e.g. 800-2500 Watts), or voltage greater than 1.5 kV (e.g. 2-3 kV). These pulse characteristics provide for reduced collateral damage, and effective cutting of tissue. Cutting is mainly provided by plasma streamers which are formed on the probe tip endface. However, cutting is also provided by shock waves formed by the discharges. The method is applicable to microsurgical procedures such as retinal surgery and capsulotomy. Also disclosed are electrical circuits for performing the method.

Abstract: Methods and systems are provided for necrosing and resecting tissue. A pair of electrodes are placed on opposed tissue surfaces, and radio frequency power is applied through the electrodes to necrose a tissue mass therebetween. After necrosis has been effected, the tissue may be resected along a plane within the necrosed region with minimum or no bleeding. The tissue mass may then be removed.

Abstract: A radio frequency generator for an electrosurgical system is provided, the system including an electrode assembly having two electrodes for use immersed in an electrically conductive fluid. The generator has control circuitry for rapidly reducing the delivered radio frequency output power by at least 50% within at most a few cycles of the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam generation. The same peak voltage limitation technique is used in a tissue vaporisation or cutting mode to limit the size of the steam pocket at the electrodes and to avoid electrode burning. The generator has a push-pull output stage with a series-resonant output circuit, the output stage being driven by a radio frequency oscillator at a frequency which, in general, differs from the resonant frequency of the resonant output circuit.

Abstract: An ultrasonic operating apparatus includes an ultrasonic vibrator, an oscillation circuit and a power amplifier which serve as a driving energy supply portion for supplying a driving energy for driving the ultrasonic vibrator. A current detector detects a driving energy supplied to the ultrasonic vibrator. A determining device determines whether or not the ultrasonic vibrator is driven normally depending on whether or not the current component of the driving energy detected by the current detector is in a predetermined range. If it is determined that the ultrasonic vibrator is not driven normally, a stop device stops a supply of the driving energy to the ultrasonic vibrator.

Abstract: A tissue ablation apparatus for minimally invasive treatment for disorders of the upper airway by the treatment of soft tissues in the upper airway comprising a hand-held device adapted to be held by the human hand. Radio frequency energy is delivered to the hand-held device. The hand-held device comprises a housing having a handle portion adapted to be grasped by the human hand and a probe portion. At least one guide tube is mounted in the probe portion and has a bore extending therethrough. A carrier block is slidably mounted in the housing relative to the guide tube. At least one needle assembly is mounted in the carrier block assembly and is movable with the carrier block assembly. The at least one needle assembly extends distally of the carrier block and is slidably disposed in the at least one guide tube. A slider is mounted on the housing exterior of the housing for slidable movement longitudinally of the housing and is adapted to be grasped by the thumb of the hand holding the housing.

Abstract: The apparatus and method of the current invention relate to electrosurgical work involving the forming of cuts in and coagulation of body tissue of a patient. The apparatus and method of the invention overcome disadvantages common with conventional dipolar and monopolar apparatus. In one aspect the invention provides a cutting tool or instrument with at least one cutting or coagulation tip and the tool is adapted to operate as both a power supply electrode to supply power to the tip and as a return electrode to allow impedance feedback signals to be received by a control means thereby eliminating the need for a separate second electrode and taking the patient out of the circuit received by a control means. According to a second aspect the feedback information is stored, processed and analysed in relation to pregrogrammed and previous actual feedback to allow alteration to the power supply to the tip to create optimum cutting and/or coagulating conditions.