In an electrosurgical generator for generating radio frequency power, the generator includes a radio frequency output stage having two or more output connections, and a power supply coupled to the output stage for supplying power to the output stage. A controller is operable to cause the generator to supply a blended output signal alternating constantly between a first output signal across the output connections in which the radio frequency output voltage developed across the output connections is limited to at least a first predetermined threshold value for cutting or vaporisation of tissue, and a second output signal across the output connections in which the radio frequency output voltage developed across the output connections is limited to a second threshold value for coagulation. There is also provided adjustment means, operable by a user of the electrosurgical generator, for changing between various preset settings for the blended signal, the preset settings each having a predetermined duty cycle of the blended signal that is limited to the first threshold value for cutting or vaporisation, and a predetermined duty cycle of the blended signal that is limited to the second threshold value for coagulation.

Electrosurgical generator and system

An electrosurgical generator has an output power control system that causes the impedance of tissue to rise and fall in a cyclic pattern until the tissue is desiccated. The advantage of the power control system is that thermal spread and charring are reduced. In addition, the power control system offers improved performance for electrosurgical vessel sealing and tissue welding. The output power is applied cyclically by a control system with tissue impedance feedback. The impedance of the tissue follows the cyclic pattern of the output power several times, depending on the state of the tissue, until the tissue becomes fully desiccated. High power is applied to cause the tissue to reach a high impedance, and then the power is reduced to allow the impedance to fall. Thermal energy is allowed to dissipate during the low power cycle. The control system is adaptive to tissue in the sense that output power is modulated in response to the impedance of the tissue.

Electrosurgical generator with adaptive power control

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. In another mode of operation, a conductive-resistive matrix can induce a “wave” of Rf energy density to sweep across the tissue to thereby weld tissue.

Electrosurgical instrument and method of use

Surgical devices for treating tissue are provided. Also provided are systems for treating tissue and methods of treating tissue. An exemplary surgical device has a handle, a fluid passage connectable to a fluid source, a tip portion and a distal end. The tip portion can simultaneously provide RF power and conductive fluid to tissue. The tip portion includes an electrode having a domed portion having a domed surface and a cylindrical portion having a cylindrical surface. The domed portion is located distal to the cylindrical portion and occupies at least a portion of the distal end of the surgical device. The device includes a fluid outlet opening in fluid communication with the fluid passage, the fluid outlet opening configured to provide the conductive fluid to a surface of the electrode proximal to the distal end surface of the surgical device.

Fluid-assisted medical devices, systems and methods

A new method for the ablation of undesirable tissue such as cells of a cancerous or non-cancerous tumor is disclosed. It involves the placement of electrodes into or near the vicinity of the undesirable tissue through the application of electrical pulses causing irreversible electroporation of the cells throughout the entire area of the undesirable tissue. The electric pulses irreversibly permeate the cell membranes, thereby invoking cell death. The irreversibly permeabilized cells are left in situ and are removed by the body immune system. The amount of tissue ablation achievable through the use of irreversible electroporation without inducing thermal damage is considerable.

Tissue ablation with irreversible electroporation

An electrosurgical bipolar RF generator apparatus includes a bipolar electrode. An aperiodic sequence of uniform width bursts of a high frequency signal are electronically synthesized. Substantially identical decaying amplitude envelopes are impressed on the bursts of the high frequency signal. Each of the envelopes has a predetermined rate of change from a preselected initial amplitude. The impressed bursts of the high frequency signal are applied to the electrode. The electrical apparatus operates in a cut mode or a coagulation mode. The apparatus includes a power supply for providing a variable DC voltage, a short circuit detect circuit for detecting a short circuit at the bipolar electrode, and an open circuit detector for detecting an open circuit at the bipolar electrode.

Bipolar RF generator

A bipolar cutter/coagulator produces a coagulating waveform comprising an aperiodic sequence of damped RF bursts. The inter-burst spacing is pseudo-random, and the intra-burst RF frequency is swept between preset limits. The burst envelopes are uniform, always starting at the same preselected amplitude.

Bipolar cutter/coagulator

An electrosurgical generator apparatus controls a variable output signal to electrodes. The generator apparatus operates in a cut mode, a coagulation mode or a stimulate mode. The generator apparatus comprises a DC power supply that provides regulated low voltage and high voltage outputs and a radio frequency (RF) waveform generator circuit that provides pulse duration modulation (PDM) of a carrier signal. The carrier signal directly affects the variable output signal to the electrodes. A control circuit controls a variable output signal to electrodes used in electrosurgical procedures. The control circuit comprises a DC power supply circuit that provides regulated low voltage and high voltage outputs and an RF waveform generator circuit that provides pulse duration modulation of a carrier signal. The carrier signal directly affects the variable output signal to the electrodes.

Electrosurgical generator apparatus

An electrosurgical bipolar instrument includes an instrument housing having a distal end, a proximal end and an elongated body therebetween. The electrosurgical bipolar instrument includes a pair of radio frequency (RF) electrodes disposed at the distal end of the instrument housing and a control circuit mounted within the instrument housing. The control circuit has a first cut/coagulate mode pad, a common pad and a first cut/coagulate mode push button configured to electrically couple the first cut/coagulate mode pad to the common pad when actuated. The electrosurgical bipolar instrument further includes a plug coupled to the proximal end of the instrument housing having first and second RF contacts electrically coupled to the pair of RF electrodes. The plug has a first cut/coagulate mode contact and a first common contact electrically isolated from the first and second RF contacts and the pair of RF electrodes.

Robert R. Acorcey

Papers

Bipolar RF generator

Bipolar cutter/coagulator

Electrosurgical generator apparatus

Electrosurgical bipolar instrument

Surgical instrument handle