| 摘要 |
Electrosurgical methods and apparatus for removing tissue from a target site of a patient, the apparatus including a probe adapted for coupling to a power supply. The electrosurgical probe includes a shaft having a first electrode type and a second electrode type. The electrosurgical apparatus/probe lacks a dedicated return electrode. Instead, the first electrode type and the second electrode type alternate between serving as active electrode and serving as return electrode. The first electrode type comprises at least one ablation electrode adapted for aggressively removing tissue from a target site. The second electrode type comprises at least one digestion electrode adapted for aggressively digesting resected tissue fragments present in an aspiration stream. The apparatus may shift from a first mode of operation wherein the first electrode type serves as active electrode, to a second mode of operation wherein the second electrode type serves as active electrode, and back to the first mode of operation, without operator input. Such a shift may be determined by the presence or absence of tissue at the first and second electrode types, or by a change in electrical impedance in the milieu of the second electrode type, and such a shift may be dependent on a suitable surface area ratio of the first electrode type to the second electrode type. The probe may include an aspiration device which accommodates an aspiration stream emanating from the target site, and a fluid delivery device for delivering an extraneous electrically conductive fluid to the probe or to the target site.
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