RF electrosurgery is performed using a RF electrosurgical generator (also referred to as an electrosurgical unit or ESU) and a handpiece including one or two electrodes—a monopolar or bipolar instrument. All RF electrosurgery is bipolar so the difference between monopolar and bipolar instruments is that monopolar instruments comprise only one electrode while bipolar instruments include both electrodes in their design.
The monopolar instrument called an "active electrode" when energized, requires the application of another monopolar instrument called a "dispersive electrode" elsewhere on the patient's body that functions to 'defocus' or disperse the RF current thereby preventing thermal injury to the underlying tissue. This dispersive electrode is frequently and mistakenly called a "ground pad" or "neutral electrode". However virtually all currently available RF electrosurgical systems are designed to function with isolated circuits—the dispersive electrode is directly attached to the ESU, not to "ground". The same electrical current is transmitted across both the dispersive electrode and the active electrode, so it is not "neutral". The term "return electrode" is also technically incorrect since alternating electrical currents refer to alternating polarity, a circumstance that results in bidirectional flow across both electrodes in the circuit.
Bipolar instruments generally are designed with two "active" electrodes, such as a forceps for sealing blood vessels. However, the bipolar instrument can be designed such that one electrode is dispersive. The main advantage of bipolar instruments is that the only part of the patient included in the circuit is that which is between the two electrodes, a circumstance that eliminates the risk of current diversion and related adverse events. However, except for those devices designed to function in fluid, it is difficult to vaporize or cut tissue with bipolar instruments.
Jinhua Huacheng Medical Appliance Co.,Ltd.
Manufactuer of disposable medical products: Electrosurgical pencil,grounding plate,skin stapler and ECG electrode
