The electro-scalpel

The electro-scalpel, also called an electric scalpel, surgical unit or HF appliance, is an electrical appliance that converts electrical energy into heat for the purpose of cutting, removing or coagulating soft tissue such as meat, thanks to currents that are above 200,000 Hz.

These frequencies are used because they only produce heat, and because using lower frequencies could interfere with the nervous processes of the body.

By the 1980s electricity as an energy application in surgery fell into disgrace. The use of the laser was hypertrophied by the same media that published cases of malpractice arising from electrosurgical complications. Patients appeared in the offices of gynecologists demanding the healing powers of the laser. Establishing throughout the country "laser centers", which required any surgeon seeking to be accredited as an expert in the use of laser a deep knowledge of the physics of the laser, which did not happen for the use of electric current.

The operation of the electric scalpel is as follows:

It circulates high-frequency current of moderate or high intensity between two electrodes applied to the body. This causes heat to be generated in the place applied and the tissue to be cut (electrosection) or coagulated (electrocoagulation).

The currents can be of two types: direct current or alternating current. In direct current, also called galvanic current, there is a continuous exchange of electrons in a single direction between two opposite poles.

In alternating current the exchange of electrons is bidirectional and the magnitude and direction vary cyclically in a sinusoidal way.

When the current is applied to human tissue, the following three effects occur:

Faradic effect: low or medium frequency alternating current causes stimulations in muscles or nerves, something that can produce tetany, extrasystolic ventricular fibrillation, or in the worst case, death. The maximum impact occurs when the current is about 100 Hz, and decreases as the frequency increases, because with high frequencies is lost its harmful effect.

Electrolytic effect: a current of ions is produced in the tissue caused by the electric current. With direct current the positive ions would move towards the negative pole and the negative ions towards the positive pole, causing tissue damage. For this reason, direct current is not used. With alternating current, on the other hand, the ions move permanently in a different direction, which does not cause any damage to human tissue.

Thermal effect: it is produced with high frequency alternating current, something that is used in current electro scalpels and that avoids the two previous effects.