An electrosurgical generator is disclosed. The generator includes an RF output stage configured to generate at least one electrosurgical waveform including a plurality of cycles; at least one sensor coupled to the RF output stage, the at least one sensor configured to measure a voltage and a current of the at least one electrosurgical waveform; and a controller coupled to the at least one sensor and the RF output stage, the controller including a proportional-integral-derivative controller having at least one of voltage limiter or a current limiter, the proportional-integral-derivative controller configured to saturate the RF output stage based on voltage-current characteristics of the RF output stage.

A surgical fluid management system delivers fluid for distending a uterine cavity to allow cutting and extraction of uterine fibroid tissue, polyps and other abnormal uterine tissue. The system comprises a fluid source, fluid deliver lines, one or more pumps, and a filter for re-circulating the distension fluid between the source and the uterine cavity. A controller can monitor fluid retention by the patient.

The plasma sensor monitors parameters characterizing the condition of the plasma during the treatment phase and/or the change thereof in order to recognize a prefiguring or already occurred interruption of the plasma in this manner and to avoid this interruption and, in the ideal case, avoid this by already changing the voltage form previously. The mentioned mechanisms can be used by the control device (22) also during a pulse packet. The length of each pulse packet is adapted at each change of the voltage form according to their characteristics in order to guarantee a constant average power.

Controlling a level of electrosurgical energy provided to tissue based on detected arcing patterns or impedance changes. The drag force imposed on an electrode or blade of an electrosurgical instrument may be controlled by adjusting the level of electrosurgical energy based on the arcing patterns or impedance changes. The arcing patterns or impedance changes may be detected by sensing and analyzing voltage and/or current waveforms of the electrosurgical energy. The current and/or voltage waveform analysis may involve calculating impedance based on the voltage and current waveforms and calculating changes in impedance over time. The waveform analysis may involve detecting harmonic distortion using FFTs, DFTs, Goertzel filters, polyphase demodulation techniques, and/or bandpass filters. The waveform analysis may involve determining a normalized difference or the average phase difference between the voltage and current waveforms.

The disclosure provides various embodiments of catheters having articulable ends that can be used for various procedures. Embodiments of methods are also provided that can be performed with catheters in accordance with the present disclosure.

A method of detecting a leakage current in an electrosurgical system operating at a high frequency includes: coupling an RF generator to a pair of RF output leads via an electrical interface, the RF generator having an operating frequency; inducing a test signal at an output of the electrical interface, the test signal having a test signal frequency that is less than the operating frequency; and monitoring for a presence of an induced common mode current that would indicate the presence of leakage current.

An arthroscopic cutting probe includes an outer sleeve having a longitudinal bore and an outer cutting window at its distal end. The outer sleeve has a metal body electrically insulated over its exterior except for a portion at least partially surrounding the outer cutting window which comprises an active electrode. An inner sleeve is rotationally disposed in a bore of the outer sleeve, and the inner sleeve has a distal end, a proximal end and a longitudinal passageway having an electrically conductive inner surface which comprises a return electrode. A dielectric cutting member is attached to the distal end of the inner sleeve and has a central passage extending from an inner cutting window at its distal end to an opening at its proximal end. The opening at the proximal end is contiguous with the longitudinal passageway in the inner sleeve, and rotation of the inner sleeve relative to the outer sleeve causes the inner cutting window to rotate past the outer cutting window to resect tissue received through the cutting windows as they pass each other.

A high-frequency generator connects an electrosurgical instrument, including an electrical output connection point for an electrosurgical instrument, a power supply, which is at least indirectly connected to the output connection point, and a power controller for controlling the electrical output power output via the output connection point. The power controller is designed to begin the output of an electrical output power when an output energy balance amount is greater than an output energy limit value and to end the output of the electrical output power when the output energy balance amount falls below a minimum value.

An apparatus (14) for supplying a medical instrument (15) for the treatment of biological tissue (11) due to the action of a plasma (28) is disposed, in accordance with the invention, in a special manner for the ignition and the stable development of a plasma (28) on the electrode (27) of the instrument (15). To accomplish this, the apparatus (14) comprises a control device (23) that, during an ignition test, limitspreferably in an instrument-specific mannerthe current deliverable to the instrument (15) and/or limits the electrical power to be output to the instrument (15), and/or, in doing so, works with a reduced operating voltage. With this measure, a rapid, stable plasma development with minimal spark play is achieved with a large variety of connectable instruments (15a-15e).

A tissue cutting device has an outer sleeve with a distal window and an inner cutting sleeve which moves past the window to cut tissue. The inner cutting sleeve has a lumen which may have a larger proximal diameter than distal diameter. A perimeter of the window may comprise a dielectric material. A distal edge of the inner sleeve may be displaced inwardly.