(19) United States
(12) Patent Application Publication (io) Pub. No.: US 2002/0029036 Al
Goble et al. (43) Pub. Date: Mar. 7,2002
(54) ELECTROSURGICAL GENERATOR AND SYSTEM
(75) Inventors: Nigel Mark Goble, Nr. Cardiff (GB);
Colin Charles Owen Goble, South
NIXON & VANDERHYE P.C.
1100 North Glebe Road
Arlington, VA 22201-4714 (US)
(73) Assignee: Gyrus Medical Limited
(21) Appl. No.: 09/924,485
(22) Filed: Aug. 9, 2001
Related U.S. Application Data
(63) Continuation ol application No. 09/048,717, filed on Mar. 26, 1998, which is a continuation-in-part ol application No. 08/642,121, filed on May 2, 1996, now Pat. No. 6,293,942.
(30) Foreign Application Priority Data
Jun. 23, 1995 (GB) 9512889.8
An electrosurgical system including an electrode assembly having two electrodes lor use immersed in an electrically conductive fluid has a generator with control circuitry for rapidly reducing the delivered radio frequency output power by at least 50% within at most a lew cycles ol the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam generation. The same peak voltage limitation technique is used in a tissue vaporization or cutting mode to limit the size ol the steam pocket at the electrodes and to avoid electrode burning. In a blended mode, the output voltage is alternately limited to a value appropriate for coagulation and a value appropriate for cutting or vaporization.