Glossary of Electrosurgery

Active (electrode)

Electrode that can be connected to the electrodes-holder handle thanks to that it is possible to transfer the HF output power to the patient, therefore, to obtain the selected performance. This electrode is used for monopolar application of electrosurgical units together with neutral electrode.

Argon

Inert gas used by special units (called “Argon coagulators”) for obtaining a coagulating effect on the patient tissue. The gas inside the tank is delivered at a low pressure towards the tissue while activating a function with high voltage, which brings the Argon’s spark, then starting the coagulating process. It's a further variant from the coagulating techniques.

Automatic Bipolar Coagulation

It is not necessary to activate bipolar coagulation by the operator; the contact between the forceps and the patient tissue activates the unit and, thus, enables the coagulation.

Bi-coagulation

See “Bipolar coagulation”.

Bipolar Coagulation

Type of coagulation which uses the bipolar forceps that permits to deliver the HF output power on an impedance having value of approximately 100 ohm. Such value is equal to the one of the tissue section which is normally between the tips of the forceps.

Bipolar (electrode)

Forcep electrode thanks to that it is possible to utilize the bipolar performances of electrosurgical units, i.e. those in which every electrode tip represents one of two poles of the circuit where the patient in included.

Bipolar (operation)

The way to use electrosurgical units being possible thanks to forcep electrodes, where the HF output power is delivered between the 2 forcep tips, thanks to that the surgeon is able to carry out small coagulations.

Blend Cut

Waveform with a percentage of modulation less than the pure coagulation. The modulation is a gap thanks to that it is possible to deliver suitable “train impulse” of HF energy. The width of the gap compared to the HF power delivery span lets the water contained inside the cells to evaporate more or less quickly. This comes to a coagulating effect more or less significant (haemostatic effect).

Coagulation

Output waveform that makes the water inside the cell to evaporate gradually, without making the cell tissue bursted (as it happens when cutting).

Cut

Particular waveform that causes a very quick evaporation of the water inside the cells of the patient tissues; at macroscopic level it is a dissection of the tissue itself.

Defibrillator

Device, compulsory by law in the operating theatre, able to supply a strong electric discharge to patients in ventricular fibrillation condition. It is used in order to recover the heart function that has suddenly stopped beating. On the electrosurgical units it must be clearly stated the protection from defibrillator discharge since, in case of emergency, it could not be able to take off the neutral electrode from the patient. In such cases the discharge does not have to create risks either for the patient or the instrumentation connected to him.

Earth-referred (unit)

Is defined as “earth-referred” an electrosurgical unit whose patient circuit is electrically separated from the protective earth or earthing equalizationsystem only as regarding the low frequency currents. It means that, when the device delivers the HF output power, the neutral electrode (and thus the patient) is connected to earth. The electrical separation between the patient circuit and the earth is normally done by the use of a capacitor that blocks the low frequency components (for which it acts as an high-valued impedance), while it becomes almost “transparent” regarding the radiofrequency output current of the device itself.

Electrode-holder pencil

Plastic accessory, with or without buttons on its body depending on the type of activation, that permits using the monopolar electrodes.

Electromagnetic compatibility

Characteristic that permits the electric units to interact with others without undergoing or causing such interferences that can compromisetheir correct operation. Some tests able to verify the electromagnetic emission level and their immunity have been carried out to verify such compatibility.

Floating (unit)

“Floating” is used for a surgical unit whose patient circuit is always found separated from the protective earth. These are units that can guarantee the highest level of safety from the dangers relevant to the dispersion currents.

Fulguration

Particular type of coagulation that permits to cauterize small blood vessels. A difference from the normal coagulations by contact, the Fulguration allows the coagulation by starting a spark that produces the desired effect with particular precision and speed, thanks to using a high voltage of output waveform.

HF Leakage current

High Frequency current whose effect can cause a burn in the patient. It's one of the main problems using an eletrosurgical unit It is normally caused by a coupling between the patient and the earth, due to an accidental contact of the patient himself with a conductive part connected to earth, or by using of other devices for monitoring during the operation.

Laparoscopy

Surgical technique that allows to operate the patient inside him abdomen. The operating field remains closed and it is possible to enter in the zone subjected for the operation thanks to three small probes (one of them is used for introducing the camera, the others for the accessories connected to the electrosurgical units) inserted in the abdomen of the patient. Where is possible to apply this technique, the post-operation recover time reduces remarkably, since the trauma due to the wound is minimized.

LF Leakage current

Electric current, normally at mains frequency , that must be absolutely kept within the limit prescribed by the general standard for the safety of the medical units CEI EN 60601-1. The observance of the imposed values avoids the risk of fulguration for the patient or the operator.

Monopolar (operation)

Way of using the electrosurgical unit by the active electrode and neutral electrode; with having these 2 electrodes, the active one is used for cutting and coagulating the patient tissue because of its very reduced surface, while the neutral one acts exclusively as return electrode.

Neuromuscular Stimolation

Effect caused by the low frequency alternating current. The central nervous system works thanks to the delivering low frequency electric pulses. A low frequency current stimulates the muscles and causes their contraction. This happens also for the cardiac muscle, that can go in “fibrillation”. To avoid such dangerous effect the frequency of the current delivered by an electrosurgical unit must be high enough in order not to allow the nerves of being able to “react”.

Neutral (electrode)

Flat electrode of surface approximately 150-200 cm² essential in monopolar working of the electrosurgical unit, that allows the “return” of the current (which has produced the cutting or the coagulation) towards the device.

Neutral plate

See “Neutral (electrode)”.

Radiofrequency

Range of requency (normally from 300 kHz up to 3 MHz) within that it is selected the operative frequency of an electrosurgical unit. Values under 300 kHz could increase the risk of neuromuscolar stimulation for the patient; values above 3 MHz could create difficulties in control the high frequency dispersion currents (and therefore could increase the burning risk on the patient).

Rated load

The value of non-reactive load resistance that results in the maximum HF output power from each operating mode of the HF surgical equipment.

Spray Coagulation

Particular kind of coagulation that takes place without contact between the active electrode and the patient tissue. The output voltage is even higher than the Fulguration and produces an effect similar to a spray of a canister (the name of “spray” comes from that).

T.U.R.

Is the acronym for “Trans-Urethral Resection”.