Abstract: An electrosurgical instrument that allows precise modulation of active Rf density in an engaged tissue volume. The working end of the instrument has a tissue-contacting surface of a conductive-resistive matrix that is variably resistive depending on its temperature. The matrix comprises a positive temperature coefficient (PTC) polymeric material hat exhibits very large increases in resistivity as any local portion increases beyond a selected temperature. In a method of use, the polymeric PTC material senses the temperature of engaged tissue in a manner akin to pixel-by-pixel sensing and thereby changes its resistance in a corresponding pixel-by-pixel manner. The instrument further carries cooling means to cause accelerated thermal relaxation of the PTC matrix during use to make the engagement surface highly responsive to temperature changes that in turn alter the matrix between being electrically conductive and electrically resistive.

Abstract: An electrosurgical working end for 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 surface of an elastomeric material with conductive elements that extend therethrough. In one embodiment, the expansion of the elastomeric material can de-couple the conductive elements from an interior electrode based temperature to modulate current flow.

Abstract: An electrosurgical medical device and method for creating thermal welds in engaged tissue. In one embodiment, at least one jaw of the instrument defines a tissue engagement plane carrying a conductive-resistive matrix of a conductively-doped non-conductive elastomer. The engagement surface portions thus can be described as a positive temperature coefficient material that has a unique selected decreased electrical conductance at each selected increased temperature thereof over a targeted treatment range. The conductive-resistive matrix can be engineered to bracket a targeted thermal treatment range, for example about 60° C. to 80° C., at which tissue welding can be accomplished. In one mode of operation, the engagement plane will automatically modulate and spatially localize ohmic heating within the engaged tissue from Rf energy application—across micron-scale portions of the engagement surface.

Abstract: An electrosurgical medical device and method for creating thermal welds in engaged tissue. In one embodiment, at least one jaw of the instrument defines a tissue engagement plane that carries a recessed central portion. In another embodiment, the controller coupled to the Rf source is adapted to switch from a power control operational mode to a voltage controlled operational mode at a selected transition impedance level.

Abstract: An electrosurgical medical device and method for creating thermal welds in engaged tissue. In one embodiment, at least one jaw of the instrument defines a tissue engagement plane carrying a conductive-resistive matrix of a conductively-doped non-conductive elastomer. The engagement surface portions thus can be described as a positive temperature coefficient material that has a unique selected decreased electrical conductance at each selected increased temperature thereof over a targeted treatment range. The conductive-resistive matrix can be engineered to bracket a targeted thermal treatment range, for example about 60° C. to 80° C., at which tissue welding can be accomplished. In one mode of operation, the engagement plane will automatically modulate and spatially localize ohmic heating within the engaged tissue from Rf energy application—across micron-scale portions of the engagement surface.

Abstract: An electrosurgical working end for 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 surface of an elastomeric material with conductive elements that extend therethrough. In one embodiment, the expansion of the elastomeric material can de-couple the conductive elements from an interior electrode based temperature to modulate current flow. In another embodiment, the elastomeric material can couple and de-couple the conductive elements from an interior electrode based engagement pressure to modulate current flow.

Abstract: An electrosurgical working end for 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 surface of an elastomeric material with conductive elements that extend therethrough. In one embodiment, the expansion of the elastomeric material can de-couple the conductive elements from an interior electrode based temperature to modulate current flow.

Abstract: An electrosurgical medical device and method for creating thermal welds in engaged tissue that carries the electrosurgical components in a disposable cartridge. The instrument also can carry a blade member in a disposable cartridge, thus making the instrument system inexpensive to use. In another embodiment, the electrical leads of the cartridge have a surface coating of a thermochromic material to provide the physician with a visual indicator of operational parameters when applying energy to tissue.

Abstract: An electrosurgical medical device and technique for creating thermal welds in engaged tissue that provides very high compressive forces. In one exemplary embodiment, at least one jaw of the instrument defines a tissue engagement plane carrying first and second surface portions that comprise (i) an electrically conductive material and (ii) a positive temperature coefficient (PTC) material having a selected increased resistance that differs at each selected increased temperature over a targeted treatment range. One type of PTC material is a doped ceramic that can be engineered to exhibit a selected positively sloped temperature-resistance curve over about 37° C. to 100° C. The 70° C. to 100° C. range can bracket a targeted “thermal treatment range” at which tissue welded can be accomplished. The engineered resistance of the PTC matrix at the upper end of the temperature range will terminate current flow through the matrix.

Abstract: Various embodiments of the invention provide polymeric compositions including PTC composites that exhibit highly non-linear PTC effects together with extremely rapid, repeatable switching within a predetermined temperature range. In one embodiment, the polymer composite includes a polymer base material with dispersed conductive particles that have very low densities and very low thermal conductivity properties. The conductive particle component can comprise hollow glass microspheres to provide low mass and low thermal conductivity properties together with a nanoscale conductive cladding of silver or gold. The conductively clad microspheres have a core portion with a bulk density of less than about 2.0 g/cm3 and a mean thermal conductivity of less than about 5.0 W/m-° K.

Abstract: An embodiment of a method of the invention provides a method for welding tissue comprising providing a tissue welding device having first and second tissue engaging surfaces with at least one surface including an electrode surface that defines a plurality of surface portions having different resistances to electrical current flow therethrough. A target tissue volume is engaged with the tissue engaging surfaces. Rf energy is delivered to the target volume to create a substantially even temperature distribution across at least a portion of the target tissue volume to substantially uniformly weld at least a portion of the target tissue volume.

Abstract: Various embodiments provide compositions that exhibit positive temperature coefficient of resistance (PTCR) properties for use in thermal interactions with tissue-including thermal sensing and I2R current-limiting interactions. Embodiments also provide tissue-engaging surfaces having PTCR materials that provide very fast switching times between low resistance and high, current-limiting resistance. One embodiment provides a matrix for an electrosurgical energy delivery surface comprising a PTCR material and a heat exchange material disposed within an interior of the matrix. The PTCR material has a substantially conductive state and a substantially non-conductive state. The heat exchange material has a structure configured to have an omni-directional thermal diffusivity for exchanging heat with the PTCR material to cause rapid switching of the PTCR material between the conductive state and non-conductive state. Preferably, the structure comprises a graphite foam having an open cell configuration.

Abstract: A particular embodiment of the invention provides an electrosurgical working end for performing high strength welding of tissue comprising a body having a tissue contacting energy delivery surface. The body includes pixel portions and non-pixel portions distributed within the tissue contacting surface. The pixel portions comprise a positive temperature coefficient of resistance (PTCR) material with at least one pixel portion configured to switch Rf current on and off in the at least one pixel portion responsive to tissue temperature adjacent the at least one pixel portion. The pixel portions can be configured to be coupled to an Rf current source such as an Rf generator. The pixelated energy delivery surfaces are capable of highly localized modulation of Rf energy application to the engaged tissue to create high strength tissue welds.

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: 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: 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 (i) a first surface conductive portion or a variably resistive matrix of a temperature-sensitive resistive material or a pressure-sensitive resistive material, and (ii) a second surface portion coupled to a fixed resistive material that coupled in series or parallel to a voltage source together with the first portion. In use, the engagement plane will apply active Rf energy to ohmically heat the captured tissue until the point in time that a controller senses an electrical parameter of the tissue such as impedance. Thereafter, the controller switches energy delivery to the second surface portion that is resistively heated to thereby apply energy to tissue by conductive heat transfer.

Abstract: Embodiments of the invention provide an electrosurgical jaw structure comprising first and second opposing jaws one or both of which include 3D variable resistance bodies. The jaw structure can be part of the working end of a surgical instrument. In one embodiment, the jaws can comprise first and second energy-delivery jaw surfaces having first and second 3D variable resistance bodies, with the jaw surface configured to be coupled to an Rf source. The 3D variable resistance bodies can define different temperature-resistance curves. The 3D bodies can be configured to control ohmic heating of tissue by modulating the delivery of Rf energy to tissue. Jaw structures having the 3D bodies can be used to engage and produce high strength tissue welds in targeted tissue including tissue volumes having varying tissue types. Such jaw structures can be configured to simultaneously apply different energy levels to each tissue type within the tissue volume.

Abstract: Various embodiments provide an electrosurgical instrument with a disposable electrosurgical cartridge. In one embodiment, the cartridge has first and second energy-delivery surfaces that carry first and second opposing polarity conductors coupled to a voltage source, together with first and second temperature-responsive variable impedance bodies exposed partly in the respective-delivery surfaces. The cartridge further carries a slidable blade member. The temperature-responsive variable impedance bodies are coupled to the voltage source by series and parallel circuitry. In use, the variable impedance bodies are adapted to modulate current flow and ohmic heating in engaged tissue by providing controlled current paths in the tissue and through the variable impedance bodies as the temperature-responsive bodies sense the temperature of adjacent engaged tissue.

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: An electrosurgical medical device for creating thermal welds in engaged tissue that provides general grasping and dissecting functionality. In an exemplary embodiment, at least one jaw of the instrument defines a tissue engagement plane carrying electrosurgical energy delivery means. The jaw assembly, in one mode of operation, can be used for general grasping and dissecting purposes wherein the jaws close in a non-parallel manner so that the distalmost jaw tip only engage tissue with little movement of the actuator lever in the handle of the instrument. In another mode of operation, the jaw assembly closes close in a parallel manner under very high compression to enable tissue welding.