The application describes systems and apparatus for applying electrical energy to tissue at a target site. In particular, an apparatus comprises an electrosurgical instrument having a shaft with a proximal end portion, a distal end portion and an aspiration lumen therebetween, the aspiration lumen having a distal opening at or near the distal end portion of the shaft. A return electrode adapted to be electrically coupled to a high frequency power supply and an aspiration electrode on the shaft in contact with the aspiration lumen are provided. A connector is provided near the proximal end of the shaft for electrically coupling the aspiration electrode to a high frequency power supply. In one embodiment, the aspiration electrode comprises a conductive screen which may be provided across the aspiration lumen.
