Abstract: An electrosurgery system includes an electrosurgical generator (10) coupled to or part of an electrosurgical instrument, the generator being operable to generate electrosurgical power in low frequency (typically at 1 MHz) and high frequency bands (typically at 2.45 GHz) either simultaneously or individually. The generator includes a load-responsive control circuit which, in one mode, causes power to be generated predominantly at 1 MHz when the load impedance is high and predominantly at 2.45 MHz when it is low. This allows automatic switching between cutting and coagulation operation. In one embodiment, the instrument includes a gas plasma generator operating such that an ionisable gas is energised in a gas supply passage by the 2.45 GHz component to form a plasma stream which acts as a conductor for delivering the 1 MHz component to a tissue treatment outlet of the passage.

Abstract: An electrosurgery system includes an electrosurgical generator (10) coupled to or part of an electrosurgical instrument, the generator being operable to generate electrosurgical power in low frequency (typically at 1 MHz) and high frequency bands (typically at 2.45 GHz) either simultaneously or individually the generator includes a load-responsive control circuit which, in one mode, causes power to be generated predominantly at 1 MHz when the load impedance is high and predominantly at 2.45 MHz when it is low. This allows automatic switching between cutting and coagulation operation. In one embodiment, the instrument includes a gas plasma generator operating such that an ionizable gas is energized in a gas supply passage by the 2.45 GHz component to form a plasma stream which acts as a conductor for delivering the 1 MHz component to a tissue treatment outlet of the passage. (FIG. 4).

Abstract: An electrosurgical instrument has coaxial inner and outer tubular members (1,2) made of a conductive material to form a coaxial transmitting line. The inner member (1) is preferably dimensioned to receive a laparoscopic tool with the working elements of the tool projecting beyond a distal end (1D) of the inner member (1). Alternatively, the inner member (1) may, itself, incorporate a working element at its distal end. The outer member (2) is connected to the inner member (1) at a distance from the distal end (1D) of the later, and a radio frequency (r.f.) feed (4) is connected to the inner member (1) distally of the connection (7) between the inner and outer members. Between the connections there is an r.f. isolating structure formed by or associated with the inner member (1) to present a series impedance between the connections (4,7) at an operating frequency of the instrument.

Abstract: An electrosurgery system has an electrosurgical generator operable to generate electrosurgical power at a frequency in the UHF band (typically 2.45 GHz), a feed structure, and an electrode assembly for delivering the electrosurgical power to tissue to be cut. The electrode assembly has an elongate active electrode which, at the operating frequency, is &lgr;/8 in length (&lgr; being the wavelength in air) and has an active surface area of less than 30 square millimeters. A return electrode set back proximally from the active electrode is arranged so as to be capacitively coupled to tissue adjacent the active electrode and is isolated from the feed structure in respect of unbalanced currents. Tissue cutting occurs due to thermal dissipation of UHF power in the tissue substantially without arcing, resulting from the lossy dielectric behavior of the tissue.