US Patent 8394088 Electrosurgical instrument with an ablation mode and a coagulation mode

Electrosurgical instruments are configured to selectively perform ablation or coagulation as desired. The electrosurgical instruments include at least two electrodes on the electrode probe that can be activated using an RF generator. The electrosurgical instruments are selectively switchable between an ablation mode and a coagulation mode by changing the amount of active electrode surface area. In particular, in the ablation mode, a relatively small electrode surface area is active. Thus, for a given power input, the current density is relatively high. In the coagulation mode, the active electrode surface area is increased, thereby reducing the current density in the coagulation mode for the given power input.