Abstract: A method and apparatus for treating tissue using an electrosurgical system. The system includes an electrosurgical system having an RF generator, a treatment electrode electrically coupled to the RF generator and positioned in contact with target tissue to be treated, and a spark gap switch positioned between the RF generator and the target tissue. The spark gap includes a threshold voltage and is configured to prevent conduction of current from the RF generator to the tissue until the voltage across the spark gap reaches the threshold voltage.

Abstract: An RF treatment apparatus includes a catheter with a catheter lumen. A removable needle electrode is positioned in the catheter lumen in a fixed relationship to the catheter. The needle electrode includes a needle lumen and a needle electrode distal end. A removable introducer is slidably positioned in the needle lumen. The introducer includes an introducer distal end. A first sensor is positioned on a surface of the needle electrode or the insulator. An RF power source is coupled to the needle electrode and a return electrode. An insulator sleeve is slidably positioned around the electrode and includes a second sensor. Resources are associated with the electrodes, sensors as well as the RF power source for maintaining a selected power at the electrode independent of changes in current or voltage.

Abstract: An RF treatment apparatus includes a catheter with a catheter lumen. A removable needle electrode is positioned in the catheter lumen in a fixed relationship to the catheter. The needle electrode includes a needle lumen and a needle electrode distal end. A removable introducer is slidably positioned in the needle lumen. The introducer includes an introducer distal end. A first sensor is positioned on a surface of the needle electrode or the insulator. An RF power source is coupled to the needle electrode and a return electrode. An insulator sleeve is slidably positioned around the electrode and includes a second sensor. Resources are associated with the electrodes, sensors as well as the RF power source for maintaining a selected power at the electrode independent of changes in current or voltage.

Abstract: Structures, processes, and mechanisms are provided for the ablation of hollow organs. Ablation structures, having deployable electrically conductive probes, are placed within a hollow organ, such as a stomach. The ablation structure typically includes a distension mechanism, whereby the hollow organ is controllably distended. The electrically conductive probes are then deployed, such that the probes extend make electrical contact with the tissue of the hollow organ, typically by extending through a mucosal layer of the hollow organ. The electrically conductive probes are typically deployed by extension of movable electrically conductive probes, from a first protected position to a second extended position. In alternate embodiments of the ablation system, the ablation apparatus includes means for vacuum-directed contact between the tissue and the electrically conductive probes.

Abstract: An apparatus and method for use in performing ablation of organs and other tissues includes a radio frequency generator which provides a radio frequency signal to ablation electrodes. The power level of the radio frequency signal is determined based on the subject area of ablation. The radio frequency signal is coupled with the ablation electrodes through a transformation circuit. The transformation circuit includes a high impedance transformation circuit and a low impedance transformation circuit. The high or low impedance transformation circuit is selected based on the impedance of the ablation electrodes in contact with the subject tissue. Vacuum level, impedance level, resistance level, and time are measured during ablation. If these parameters exceed determinable limits the ablation procedure is terminated.

Abstract: Methods and apparatus are provided for cleaning a thin disc. In accordance with a first aspect, an apparatus is provided that includes a tank adapted to contain a fluid, and at least one support mechanism adapted to support a thin disc such that the thin disc is at least partially submerged in the fluid. The apparatus further includes a plurality of transducers each adapted to produce energy waves in the fluid, and a controller adapted to adjust the energy waves produced by each transducer so as to scan an energy wave maximum along a surface of a thin disc supported by the at least one support mechanism.

Abstract: A working end of a surgical instrument that carries first and second jaws for delivering energy to tissue. In a preferred embodiment, at least one jaw of the working end defines a tissue-engagement plane that contacts the targeted tissue. The cross-section of the engagement plane reveals that it defines a surface conductive portion that overlies a variably resistive matrix of a temperature-sensitive resistive material or a pressure-sensitive resistive material. An interior of the jaw carries a conductive material or electrode that is coupled to an Rf source and controller. In an exemplary embodiment, the variably resistive matrix can comprise a positive temperature coefficient (PTC) material, such as a ceramic, that is engineered to exhibit a dramatically increasing resistance (i.e., several orders of magnitude) above a specific temperature of the material.

Abstract: An electrosurgical working end for instant and automatic modulation of active Rf density in a targeted tissue volume. The working end of the probe of the present invention defines a tissue-engagement plane that is adapted to contact the targeted tissue. The cross-section energy delivery apparatus comprises (i) a conductive surface engagement plane for tissue contact, (ii) a substrate comprising a medial conductive matrix of a temperature sensitive resistive material; and (iii) an inner or core conductive material (electrode) that is coupled to an Rf source and controller. Of particular interest, the medial conductive matrix comprises a positive temperature coefficient (PTC) that exhibits very large increases in resistivity as it increases beyond a selected temperature, which is described as a switching range. The PTC material is selected and fabricated to define a switching range that approximates a particular thermally-mediated therapy.

Abstract: A surgical system for controlled application of ultrasound energy to engaged tissue volumes for creating effective biological welds or seals in tissue. The invention provides an ultrasound transmission assembly including piezoelectric elements coupled to an elongate waveguide that is reciprocatable in an interior of an introducer. The reciprocatable waveguide assembly of the invention is adapted to have multiple functionality: (i) to couple ultrasound energy to both opposing jaws to thereby deliver energy to both sides of engaged tissues to create uniform thermal weld effects; (ii) to apply very high compressive forces to captured tissues over the length of elongate jaws by engaging substantially the entire length of the jaws, and (iii) to transect the captured tissues contemporaneous with the delivery of energy to create the thermal weld.

Abstract: An apparatus and method for use in performing ablation of organs and other tissues includes a radio frequency generator which provides a radio frequency signal to ablation electrodes. The power level of the radio frequency signal is determined based on the subject area of ablation. The radio frequency signal is coupled with the ablation electrodes through a transformation circuit. The transformation circuit includes a high impedance transformation circuit and a low impedance transformation circuit. The high or low impedance transformation circuit is selected based on the impedance of the ablation electrodes in contact with the subject tissue. Vacuum level, impedance level, resistance level, and time are measured during ablation. If these parameters exceed determinable limits the ablation procedure is terminated.

Abstract: An improved biopsy needle assembly for efficient removal of multiple biopsy cores from a single needle penetration. The needle apparatus comprises an elongate assembly of paired sleeves with an open notch in the wall of the outer sleeve for engaging a tissue volume in the bore of that sleeve. An inner sleeve or blade member with a sharp blade edge is moveable from a retracted position to an extended position to both (i) excise the tissue volume, and (ii) function as valve means to alter the open notch between an open position and a closed position. The invention provides a looped inflow-outflow passageway system for using high-pressure fluid flows to push or expel the excised tissue from the bore in working end where the excised tissue is captured. The looped passageway system is coupled to a remote pressurization source.

Abstract: A system for occlusion of aneurysms comprising a class of polymer embolic elements that carry a conductive material to provide the element with a specified resistivity. The embolic element is introduced into a targeted vascular malformation from a catheter sleeve that carries an electrode arrangement at its distal terminus. After introducing any selected length of the embolic element into the vascular malformation to mechanically occlude the malformation, the physician delivers electrical current within a first selected power range to the electrode at the catheter terminus. The electrical current flows to the embolic element wherein the specified resistivity of the element controllably causes a selected thickness of coagulum to form about the surface of the embolic element to more fully occupy the volume of the malformation with occlusive material.

Abstract: Methods for heating tissue completely, thoroughly, and uniformly comprise delivering radio frequency energy through a bipolar surgical instrument having first and second jaws with first and second electrode members within the treatment region. Tissue is grasped between the first and second jaws of the bipolar instrument. The electrode members are energized at a power level to deliver electrical energy to and heat tissue between the first and second electrode members. The power level is increased at a predetermined rate from an initial level. The initial level and predetermined rate are selected to avoid creating a vapor layer and to permit an impedance increase to occur as a result of complete tissue desiccation. A tissue impedance may also be measured and compared to a preset impedance limit for terminating the power delivery when the measured impedance exceeds the impedance limit.

Abstract: An electrode catheter assembly for ablation of obstructive material formed within and around a stent inserted within a lumen includes an elongate flexible tube having a distal end and a proximal end, and an electrode assembly attached to the distal end of the tube. The electrode assembly includes: a first electrode formed by a cylindrical body defining a longitudinal axis and having a first end, and an opposite second end, the body having a plurality of slits formed therein, each of the slits extending parallel to the axis from a corresponding first point proximate the first end to a corresponding second point proximate the second end, the slits defining a plurality of elongated deformable segments; and a second electrode disposed along the axis at a distance from the first electrode. A spacer means, disposed between the first and second electrodes, is operative to physically separate and electrically insulate the first electrode from the second electrode.

Abstract: A method is provided for stimulating nerve growth, especially for nerve regeneration after damage to the nerve. The method comprises: applying thermal energy to one or more nerve segments adjacent a damaged region of the nerve, such that nerve fibers from the treated adjacent segment are stimulated to grow and extend toward the damaged region. The method may be used to enhance mechanical stimulative effect at a terminus of a severed nerve or a region of nerve injured by crush or other physical forces. The method may also be used to treat nerve segments retrograde up the nerve fiber and to increase the response of the injured nerve to regrowth and extension rapidly. An apparatus for delivery of thermal energy to the distal terminus of the severed nerve or region is disclosed. Thermal conductive or electromagnetic energy is delivered through a probe having a handle and a shaft.

Abstract: A method and apparatus for treating tissue using an electrosurgical system. The system includes an electrosurgical system having an RF generator, a treatment electrode electrically coupled to the RF generator and positioned in contact with target tissue to be treated, and a spark gap switch positioned between the RF generator and the target tissue. The spark gap includes a threshold voltage and is configured to prevent conduction of current from the RF generator to the tissue until the voltage across the spark gap reaches the threshold voltage. The method includes the steps of using the RF generator to apply a voltage across the spark gap switch, the spark gap switch causing conduction of current from the RF generator to the target tissue once the voltage across the spark gap reaches the threshold voltage.

Abstract: An ablation apparatus has an expandable member that is inserted into an organ of a body and ablates all or a selected portion of the inner layer of the organ. Electrolytic solution fills the expandable member, and the expandable member includes a plurality of apertures from which electrolytic solution flows from the expandable member. First and second fluid conduits, which can be first and second conforming members, are in a surrounding relationship to the expandable member. The second conforming member, including a conductive surface, is made of a material that provides substantial conformity between the conductive surface and a shape of the inner layer of the organ. A plurality of electrodes is positioned between the two conforming members. The expandable member serves as an insulator to RF energy. Each electrode includes an insulator formed on a surface of the electrode positioned adjacent to the second conforming member.

Abstract: A method for controlled removal of surface tissue layer portions with a non-contact energy delivery modality that applies electrical energy to the targeted tissue surface to cause electrochemical ablation. The system provides (i) a UV energy source for irradiating a beam path through a selected neutral gas environment overlying the targeted tissue thereby creating an ionized gas volume (i.e., a conductive non-equilibrium plasma), and (ii) an electrical source for creating an intense electrical field in the ionized gas volume to thereby apply energy to the targeted surface layer to cause volatilization and removal of the surface layer in a plasma-mediated ablation. The ultrafast plasma creation events are repeated at a high repetition rate to ablate surface layer portions in a controlled manner.

Abstract: An electrosurgical aspiration instrument that permits aspiration of an area being treated by the instrument. The instrument is coupled at a proximal end to a power source and includes an energy application surface area at a distal end. The power source supplied energy to the energy application surface area such that the distal end of the instrument may apply energy to the treatment area to modify the characteristics of biological material, such as biological tissue in the area. An aspiration lumen is formed through the instrument with an opening through the energy application surface area. The energy application surface area is configured to reduce blockage of the opening. Accordingly, aspiration may be performed simultaneously with electrosurgical treatment whereby unwanted matter such as by-products, biological debris and excess fluid is removed from the treatment area.

Abstract: An electrosurgical aspiration instrument that permits aspiration of an area being treated by the instrument. The instrument is coupled at a proximal end to a power source and includes an energy application surface area at a distal end. The power source supplied energy to the energy application surface area such that the distal end of the instrument may apply energy to the treatment area to modify the characteristics of biological material, such as biological tissue in the area. An aspiration lumen is formed through the instrument with an opening through the energy application surface area. The energy application surface area is configured to reduce blockage of the opening. Accordingly, aspiration may be performed simultaneously with electrosurgical treatment whereby unwanted matter such as by-products, biological debris and excess fluid is removed from the treatment area.