Electrosurgery, what is it and how does it work?

The electrosurgery unit, or electrosurgery, is a medical device that uses electrical phenomena to produce heat; Its objective is to coagulate, fulgurate, desiccate or cut tissues, depending on the established parameters. Heat production is achieved through the passage of an oscillatory electric current, concentrated in a small area. The smaller the space in which the current flows, the greater the energy density at this point, which causes increasing temperatures.

The heat energy comes from electrons moving from atoms at the rate of a difference in electrical potential; This movement of particles produces photons that carry energy, which is transformed into heat energy.

What are the parts of the electrosurgery?

The electrosurgery consists essentially of the following parts:

  • Indicators of the operating modes.
  • Power selectors.
  • Electrodes.
  • Foot switch.

The energy necessary for its operation is taken from the power grid, and is transformed into direct current by the internal power supply. This module is responsible for providing energy to all others. The radio frequency oscillator module creates the carrier wave, and the coagulation oscillator the modulating signal. These two waves are mixed in the modulator. They are then enlarged in the power amplifier, to exit, according to selection, by the monopolar socket towards the electrosurgery pencil, or the bipolar socket, towards the coagulating clamp.

What are the waveforms used?

Before defining the modes of operation, we must highlight the characteristics of each type of wave that can be used. In this case, the wave refers to alternating current variations. Among the types of waves we find: highly damped, moderately damped, combined current, pure sine wave

What are the modes of operation of an electrosurgery?


In this mode, the direct current frequency induces heat in the form of a wave and explodes the tissue cells immediately in front of the guided sheet. To obtain the cutting condition technically, contact electrodes as thin as possible will be used; a high frequency sine wave must be generated, above 350 kHz, called a carrier, with a sufficient potential difference (around 1 000 V) to supply the energy needed. This wave is still called in modern equipment “fully filtered wave”. Cut the tissues similar to the scalpel, but with less bleeding. The non-modulated current produces very little coagulation.


Electrosurgical fulguration refers to the use of a single treatment electrode capable of producing a spark without touching the tissue. In this process the tissue is superficially carbonized by repeated electrosurgical arcs and high voltage, which quickly raise the temperature to reach or exceed 200 ยฐ C. To achieve this, the electrode must be a few millimeters above, so that the discharge passes through said continuity solution.


Electrosurgical desiccation is the superficial destruction of tissues, by dehydration. It is essentially the same as fulguration, except that the treatment electrode is in contact with the tissue and does not produce sparks. The tip of the electrode moves smoothly across the surface of the treated lesion or is inserted into the thick keratotic lesions to allow deeper penetration of the current. The treated tissue shrinks and can be removed with gauze or a curette. Haemostasis is achieved by placing the treatment tip directly on the bleeding vessel or by touching with the tip of the treatment electrode a clamp that takes the vessel.


Coagulation by electro-scalpel produces protein denaturation and uses a doubly terminated method. In electrocoagulation the current is of a low voltage and high amperage. Because of this, it produces more heat than desiccation, with greater destructive effect, so it is more penetrating. The wave is modulated with a sine wave half wave called a partially rectified wave. Coagulated tissue seems โ€˜cookedโ€™ rather than scorched, hence it is also called โ€˜whiteโ€™ coagulation. This electrosurgical method uses a monopolar or bipolar current with moderate modulation.

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