Abstract: A high frequency power supply for applying electrical energy to a target site on or within a patient's body includes an electrical output driver, an output current sensor detecting the current output from the driver, and a power limiting device coupled to the current sensor during normal conditions, the power limiting device operates on a continuous basis. When current output exceeds a predetermined threshold level, the power limiting device is adapted to reduce power on the output driver to a standby mode. The power limiting device operates on a periodic detection or duty cycle when in the standby mode. The power limiting device switches into the stand-by mode to prevent excessive power drains. The power supply operates at a low power, pulsatile manner when an attached probe is in conductive or isotonic fluid but is not engaging body tissue or near a high impedance source. In this pulsatile mode, the power supply operates in a cyclical manner, typically at a predetermined duty cycle.

Abstract: Systems and methods are provided for removing fatty tissue underlying a patient's epidermis (e.g., blepharoplasty, brow lifts, eyelid shortening procedures, and the like). These methods include positioning one or more active electrode(s) and one or more return electrode(s) in close proximity to a target site on an external body surface of the patient. A high frequency voltage difference is applied between the active and return electrode(s), and the active electrode(s) are translated across the external body surface to create an incision therein. The bipolar configuration controls the flow of current to within and around the distal end of the probe, which minimizes tissue necrosis and the conduction of current through unwanted paths in the patient. The residual heat from the electrical energy also provides simultaneous hemostasis of severed blood vessels, which increases visualization and improves recovery time for the patient.

Abstract: Systems and methods are provided for resecting and/or ablating tissue within the urethra, prostate and bladder, such as transurethral resection of the prostate (TURP). A resectoscope includes an active loop electrode and a return electrode oversheath for applying high frequency electrical energy therebetween. Electrically conductive fluid, e.g., isotonic saline, is delivered to the target site to generate a current flow path between the active and return electrodes, and it allows for a new mechanism for ablation or molecular dissociation of tissue. The isotonic saline also eliminates the complications associated with the use of hypotonic (low salt) irrigating solutions.

Abstract: The present invention provides systems and methods for selectively applying electrical energy to a target location within the head and neck of a patient's body, particularly including tissue in the ear, nose and throat. The present invention applies high frequency (RF) electrical energy to one or more electrode terminals in the presence of electrically conductive fluid to remove and/or modify the structure of tissue structures. Depending on the specific procedure, the present invention may be used to: (1) volumetrically remove tissue (i.e., ablate or effect molecular dissociation of the tissue structure); (2) shrink or contract collagen connective tissue; and/or (3) coagulate severed blood vessels. For example, the present invention may be useful for ablation and hemostasis of tissue in sinus surgery (e.g., chronic sinusitis or the removal of turbinates, polypectomies), collagen shrinkage, ablation and/or hemostasis in procedures for treating snoring and obstructive sleep apnea (e.g.

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: Systems and methods are provided for treating tissue within a patient's spine, such as laminectomy/discectomy procedures for treating herniated disks, posterior lumbosacral and cervical spine fusions and the like. An electrosurgical probe includes one or more electrode terminal(s) and a return electrode coupled to a high frequency voltage supply. Electrically conductive fluid, such as isotonic saline, is delivered to the electrode terminal, and a high frequency voltage difference is applied between the electrode terminal and the return electrode to treat tissue within the spine. The isotonic saline provides a current flow path between the electrode terminal and the return electrode, and it allows for a new mechanism for ablation or molecular dissociation of tissue within the spine.

Abstract: Systems, apparatus and methods are provided for canalizing or boring channels, divots, trenches or holes through tissue to revascularize the region around this tissue. In one method, an electrode terminal is positioned in close proximity to a target site and a high frequency voltage difference is applied between the electrode terminal and a return electrode to volumetrically remove or ablate tissue at the target site. The electrode terminal(s) may be translated relative to the body structure during or after the application of electrical energy to sculpt a void within the body structure, such as a hole, channel, stripe, crater, divot or the like. The present invention may be useful for revascularization of a healthy meniscus, or a torn or damaged meniscus during a repair procedure.

Abstract: The present invention provides systems and methods for selectively applying electrical energy to a target location within the head and neck of a patient's body, particularly including tissue in the ear, nose and throat. The present invention applies high frequency (RF) electrical energy to one or more electrode terminals in the presence of electrically conductive fluid to remove and/or modify the structure of tissue structures. The present invention is particularly useful for treating sleep obstructive disorders, such as sleep apnea and snoring.

Abstract: An electrosurgical probe (10) comprises a shaft (13) having an electrode array (58) at its distal end and a connector (19) at its proximal end for coupling the electrode array to a high frequency power supply (28). The shaft includes a return electrode (56) recessed from its distal end and enclosed within an insulating jacket (18). The return electrode defines an inner passage (83) electrically connected to both the return electrode and the electrode array for passage of an electrically conducting liquid (50). By applying high frequency voltage to the electrode array and the return electrode, the electrically conducting liquid generates a current flow path between the return electrode and the electrode array so that target tissue may be cut or ablated. The probe is particularly useful in dry environments, such as the mouth or abdominal cavity, because the electrically conducting liquid provides the necessary return current path between the active and return electrodes.

Abstract: The present invention provides systems and methods for selectively applying electrical energy to a target location within the head and neck of a patient's body, particularly including tissue in the ear, nose and throat. In one aspect, a method is provided for reducing the volume of enlarge swollen tissue in the patient's nose, such as swollen nasal tissue, mucus membranes, turbinates, polyps, neoplasms, cartilage (e.g., the nasal septum) or the like. In particular, the turbinates are treated by positioning one or more electrode terminal(s) adjacent to the turbinates, and delivering electrically conductive fluid, such as isotonic saline, to the nasal cavity to substantially surround the electrode terminal(s) with the fluid.

Abstract: The present invention provides systems and methods for selectively applying electrical energy to a target location within the head and neck of a patient's body, particularly including tissue in the ear, nose and throat. The present invention applies high frequency (RF) electrical energy to one or more electrode terminals in the presence of electrically conductive fluid to remove and/or modify the structure of tissue structures. The present invention is particularly useful for removing occlusive media within the small body passages connected to sinus cavities within the patient's nose to treat chronic sinusitis.

Abstract: The present invention provides systems and methods for selectively applying electrical energy to a target location within a patient's heart to remove calcified deposits and fibroid material from valve leaflets. The method of the present invention comprises positioning an electrosurgical probe or catheter adjacent the target site so that one or more electrode terminal(s) are brought into at least partial contact or close proximity with the target heart valve. High frequency voltage is then applied between the electrode terminal(s) and one or more return electrode(s) to volumetrically remove or ablate at least a portion of the calcified material while minimizing damage to the heart valve and substantially preserving the elastic fiber layer of the valve leaflets.

Abstract: The present invention provides systems and methods for selectively applying electrical energy to a target location within a patient's brain and spinal cord. The systems and methods of the present invention are particularly useful for treating cerebrovascular diseases, such as vessel occlusion, or for the volumetric removal or ablation of intracranial tumors or Arteriovenous Malformations (AVMs). The method of the present invention comprises positioning an electrosurgical probe or catheter adjacent the target site so that one or more electrode terminal(s) are brought into at least partial contact or close proximity with a body structure within the patient's head or neck, such as tumor tissue or an occlusion within a blood vessel. High frequency voltage is then applied between the electrode terminal(s) and one or more return electrode(s) to volumetrically remove or ablate at least a portion of the body structure in situ.

Abstract: A method for transmyocardial revascularization of the heart of a patient includes positioning an active electrode surface in close proximity to a target site on the wall of a patient's heart, and applying high frequency voltage between the active voltage surface and a return electrode to ablate tissue at the heart wall. The high frequency voltage ablates, i.e. volumetrically removes the heart tissue, and the electrode surface is axially translated into the space vacated by the removed tissue to bore a channel through the heart tissue. The active electrode surface may be introduced into the thoracic cavity and placed adjacent the epicardium to form an inward channel toward the ventricular cavity, or it may be delivered into the ventricular cavity of the heart and positioned adjacent the endocardium to form a channel extending outward towards the epicardium.

Abstract: A system and method for surface tissue ablation on the patient's outer skin, such as the epidermis or the underlying dermis. An electrosurgical probe (130) comprises a shaft (132) having an array of active electrodes (136) on its distal tip and a connector (134) at its proximal end for coupling the electrode array to a high frequency power supply. An electrically conducting liquid is directed along a fluid flow path (142) past a return electrode surface (138) to the target site to provide a current flow path between the target site and the return electrode. High frequency voltage is then applied to the active and return electrodes so that an electric current flows from the active electrode, through a layer of vapor formed at the tip of the electrode, and to the return electrode through the current flow path provided by the electrically conducting liquid.

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.

Abstract: Cardiac output is measured utilizing a catheter in conjunction with the indicator dilution technique. Non-thermal analyte-containing fluid is used as the injectate. This fluid is biocompatible with and metabolizable within the body of the patient. An analyte concentration sensor is mounted upon the catheter and located downstream within the bloodstream from the port from which the analyte-containing fluid is expressed. Because of the matching of rapid concentration sensor response with an analyte-containing fluid which is metabolizable, the measurement of cardiac output may be carried out as often as about one to three minutes in conjunction with an infusion interval substantially less than the measurement frequency interval. The analyte-containing fluids are selected from a group consisting of ammoniacal fluid, heparin, ethanol, a carbon dioxide releasing fluid, glucose, and anesthesia agent.

Abstract: A resistively heated thermally cutting and coagulating surgical instrument which may be employed with a conventional electrosurgical generator having bipolar output ports and a bipolar cable. The instrument utilizes a heating element which is heated to a predetermined upper temperature limit while in still air under a starting condition. Under this condition, heat dissipation by radiation, convection, and conduction through the instrument itself provides a high temperature end form of regulation. Under a subsequent working condition wherein the heated component or element is in contact with the tissue, heat dissipation is by thermal conduction both into the tissue and through the thermally conductive components of the instrument.

Abstract: Dual program audio apparatus is provided having two or more sources of input audio program signals, switching circuitry for selecting two of the input audio signals for amplification, one or more amplifiers for amplifying the selected input audio program signals, and one or more audio speakers for enabling a listener to hear both audio programs simultaneously. Volume control circuitry is provided for selecting a higher volume level for a foreground program and a relatively lower volume for a background program and circuitry is provided for selectively interchanging the foreground and background programs either instantaneously or gradually and continuously.