Abstract: Method, system and apparatus for carrying out electrosurgical procedures interstitially. Elevated temperature fluid such as steam generated by an instrument born electrosurgical cutting arc is evacuated through an intake port located adjacent the cutting electrode. Instrument cannula surface heating caused by transport of the heated fluid is isolated. Such thermal isolation is provided by a thermal shield which may be configured as an enveloping sheath.

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: Samples are recoverable from very dense tissue utilizing an instrument incorporating a capture component formed with leafs extending to leaf tip regions supporting a stainless steel pursing cable assembly. The cables of this assembly are electrosurgically excited to define a confronting leading edge and extend rearwardly to a terminator component. Motor drive is imparted to the capture component to deploy the leafs at a substantially constant initial angle of attack. During this procedure the terminator component is drawn forwardly by the cable until encountering a cable stop whereupon continued motor operation loads the cables in tension. By applying a preliminary loading tension to the cables before encountering the pursing cable stop, the angle of attack of the leaf tip region is gradually altered to lessen the development of lateral tissue induced forces against the leaf structures.

Abstract: The capture component of tissue retrieval apparatus is strengthened to improve its structural integrity when utilized within very dense tissue. Eyelet structures carrying pursing cable are improved through the utilization of slightly expanded constant widths with diminished lengths to avoid fold back phenomena. The pursing cables employed with the capture component exhibit more than a 100% improvement in tensile strength at high electrosurgical cutting temperatures through the utilization of strands having about a 1.4 mil diameter formed with a type 316 stainless steel.

Abstract: An electrosurgical generator which provides a constant power output particularly suited for cutting arc formation at an active electrode which exhibits a dynamic active surface area of varying geometry. Essentially constant power-based control is achieved through the utilization of a d.c. link voltage the level of which functions to establish the amplitude of the output of an RF resonant inverter. A dual loop feedback control is described wherein output power based control signals are slowly introduced at low gain, while link voltage based controls are comparatively rapidly applied. Enhanced development of a controlling d.c. link voltage is achieved through the utilization of an input network incorporating a power factor correction stage.

Abstract: An electrosurgical generator which provides a constant voltage and variable power output particularly suited for cutting arc formation at an active electrode which exhibits a dynamic active surface area of varying geometry. Essentially constant voltage-based control is achieved through the utilization of a d.c. link voltage the level of which functions to establish the amplitude of the output of an RF resonant inverter. A dual loop feedback control is described wherein output voltage based control signals are slowly introduced at low gain, while link voltage motor-based controls are comparatively rapidly applied. Enhanced development of a controlling d.c. link voltage is achieved through the utilization of an input network incorporating a power factor correction stage.

Abstract: Method, system and apparatus for carrying out accurate electrosurgical cutting. A thin resilient electrode is utilized at the forward end region of an instrument which is deployable from a longitudinally disposed slot positioned rearwardly of the tip of the instrument. Lateral sides of the slot extend between a forward location adjacent the tip and a rearward location. The electrode is deployed by urging it forwardly in compression to form an arch profile supported by the abutting slot sides adjacent the forward and rearward locations. Electrosurgically excitable with a cutting output, the electrode may carry out a cutting action both during its deployment and retraction into the noted slot. This permits a pivoting maneuver effective for circumscribing a volume of targeted tissue.

Abstract: System, method and apparatus for carrying out the recovery of an intact volume of tissue wherein a delivery cannula distal end is positioned in confronting adjacency with the volume of tissue to be recovered. A capture component formed of a plurality of metal leafs is deployed from the distal end of the delivery cannula. The tips of these leafs carry a pursing cable assembly which is electrically excited to electrosurgically cut around and circumscribe the tissue volume. These pursing cables are tensioned to complete the envelopment of the tissue volumes by drawing the leaf tips together. Drive to the capture component ultimately is developed from an electric motor and electrosurgical cutting current is supplied initially at a boost voltage level and thereafter at a lower normal cutting voltage level.

Abstract: Methods and apparatus are provided for cauterizing predetermined volumes of abnormal biological tissue using a user selectable or adjustable energy applicator including two or more electrodes having electrode parameters configured cause cauterization of predetermined volumes when operated in a bipolar mode. The energy applicators are employed with a control device that couples the energy applicators to a power source and includes circuitry for interrupting activation of the energy applicator when the current between the two or more electrodes decreases more than a predetermined amount from the current sensed upon initial activation of the energy applicator.

Abstract: Apparatus system and method for cauterizing a volume of tissue wherein electrode assemblies are deployed from the forward end region of an instrument in conjunction with an electrosurgical cutting activity. Upon deployment to one or more deployed orientations, the electrodes assemblies are made biactive and the cauterization of tissue is carried out in a bipolar fashion. Following the procedure, the electrode assemblies are retracted toward the instrument and the instrument is withdrawn from the tissue region.

Abstract: System, method and apparatus for carrying out the recovery of an intact volume of tissue wherein a delivery cannula distal end is positioned in confronting adjacency with the volume of tissue to be recovered. An expandable metal capture component is expressed from the distal end of the cannula to expand while being electrically excited to electrosurgically cut around and circumscribe the tissue volume. Pursing cables are tensioned to complete the envelopment of the tissue volume, whereupon the volume is recovered by withdrawal of the instrument.

Abstract: Methods and apparatus are provided for cauterizing predetermined volumes of abnormal biological tissue using a user selectable or adjustable energy applicator including two or more electrodes having electrode parameters configured cause cauterization of predetermined volumes when operated in a bipolar mode. The energy applicators are employed with a control device that couples the energy applicators to a power source and includes circuitry for interrupting activation of the energy applicator when the current between the two or more electrodes decreases more than a predetermined amount from the current sensed upon initial activation of the energy applicator.

Abstract: Methods and apparatus are provided for cauterizing predetermined volumes of abnormal biological tissue using a user selectable or adjustable energy applicator including two or more electrodes having electrode parameters configured to cause cauterization of predetermined volumes when operated in a bipolar mode. The energy applicators are employed with a control device that couples the energy applicators to a power source and includes circuitry for interrupting activation of the energy applicator when the current between the two or more electrodes decreases more than a predetermined amount from the current sensed upon initial activation of the energy applicator.

Abstract: Apparatus and methods are provided for performing an in situ characterization of a tissue mass which may be normal, malignant, or benign, and, based on the measured characteristics of the tissue mass, therapeutically treating the tissue mass to cause necrosis of the tissue. In an illustrative preferred embodiment, the characterization of the tissue is accomplished by measuring an electrical property of the tissue, such as electrical impedance, while treatment is accomplished by supplying heat to the tissue to induce cauterization.