Patent ID: 8361065

Claim:
An electrosurgical instrument or system for selectively ablating or coagulating tissue at a surgical site during a surgical procedure, the electrosurgical instrument or system being switchable between an ablation mode and a coagulation mode, the electrosurgical instrument or system comprising: an elongate probe having a proximal end portion and a distal end portion; a first electrode positioned at the distal end portion of the elongate probe, the first electrode having a first surface area so as to generate a first current density sufficient to ablate tissue when a first amount of power is delivered to the first electrode during operation in an ablation mode; a coagulation electrode positioned at the distal end portion and electrically isolated from the first electrode, the coagulation electrode having a second surface area that is at least 10% greater than the first surface area so as to generate a second current density that is less than the first current density so as to coagulate tissue when a second amount of power greater than the first amount of power is delivered to the coagulation electrode during operation in a coagulation mode; and a user operable switch electrically coupled to the first electrode and to the coagulation electrode for selectively delivering power from a power generator to one or both of the first electrode or coagulation electrode, the user operable switch providing user selectable switching between the ablation mode and the coagulation mode, wherein: when the electrosurgical instrument or system operates in the ablation mode, the switch selectively causes the first amount of power to be delivered only to the first electrode and not to the coagulation electrode so as to generate the first current density at the first electrode sufficient to ablate tissue, and when the electrosurgical instrument or system operates in the coagulation mode, the switch selectively causes the second amount of power to be delivered to at least the coagulation electrode so as to generate the second current density at the coagulation electrode and optionally also at the first electrode sufficient to coagulate tissue.