Leakage current Current which flows along an unwanted path, normally to the earth potential.

In insulated high-frequency surgery, this is high-frequency current flowing to the earth potential.

Active electrode HF surgical instrument or accessory which concentrates the electrical

(therapeutic) current in the operating site.

Adapter Ampere (A)

Tipping the vessel forceps/forceps coagulation

Output current/voltage/power Auto bipolar

Bipolar output

Bipolar HF surgery

Bipolar instrument


Crest factor

CUSA system

Desiccation Direct coupling


Effective voltage

Electrosurgery (HF surgery)


Earth potential




Vessel forceps

Connection between incompatible connectors and sockets, facilitating correct connection and closure of the current circuit.

Unit of measurement for electrical current. One ampere (A) corresponds to 6.242 x 1018 electrons per second.

Surgical procedure for coagulating bleeding blood vessels, where the active electrode makes contact with the vessel forceps: the current passes through the vessel forceps to the target tissue. Typical for contact coagulation. The current, voltage or power produced by an electrical device, e.g. HF surgical device (HF generator, HF device).

Mode selected by a user, allowing for automatic application and interruption of the bipolar current depending on the impedance of the tissue between the branches of the bipolar forceps.

Insulated output in HF surgery where the electrical current flows between two bipolar electrodes positioned around the tissue to achieve a surgical effect in this tissue (usually desiccation).

HF surgical procedure where the electrical current flows between two bipolar electrodes positioned around the tissue to achieve a surgical effect in this tissue (usually desiccation). The current flows from one electrode through the target tissue to the other, closing the circuit, without the current penetrating in any other part of the patient's body.

HF surgical instrument or accessory in which the active and neutral electrodes are close together.

Wave mode including both incision and coagulation wave modes; current for incision with different levels of haemostasis.

Dimension for the capability of a coagulation form to achieve haemostasis without separating or cutting tissue. A higher crest factor indicates better coagulation with less tissue damage.

Cavitational ultrasonic dissector and aspirator produced by Valleylab, with selective tissue removal in contrast to ultrasonic knives. Can be used for ultrasonic high-frequency surgery.

HF surgical effect of hydrating the tissue and denaturising the protein, resulting from direct contact between the HF surgical electrode and the tissue. Condition occurring when an electrical conductor (the active electrode) has direct contact with another, second conductor (e.g. endoscope, forceps). The electrical current flows from the first conductor to the second and supplies it with energy.

Conductor transferring or receiving the HF surgical current. see also active electrode, neutral electrode.

Effective amount of voltage; square mean voltage (mean amount of voltage at any point in time) of a wave mode.

Achieving the required surgical effect by conducting high-frequency electrical current through the tissue.

Fibre-optic tubular or hose-shaped instrument for examining body cavities and organs.

Universal conductor and joint current return point for electric circuits; earthing.

Speed at which a cycle repeats. In HF surgery, the number of cycles per second in which the direction of current changes.

Use of electrical arcs (sparks) for coagulating tissue. The sparks jump from the electrode across an air gap to the tissue.

Discharge of electric current across an air gap; essential for incision and fulguration procedures in HF surgery.

Forceps for clamping a bleeding vessel to stop the flow of blood.

Generator Haemostasis Hertz (Hz)

HF surgery (electrosurgery)

HF surgical device HF surgical circuit

HF surgery burns

High frequency (HF) Impedance

Instant Response Technology


Insulated output

Insulation Insulation fault


Capacitive coupling

Coagulation Coagulation mode Coagulation across forceps/clip

Electrode holder

Cross coupling Short circuit


Device which converts low-frequency alternating current into high-frequency HF surgical current (HF surgical device, HF generator, HF device). Coagulation; in HF surgery, the use of heat generated by the HF current to stop the bleeding of a cut blood vessel.

Unit of measurement for frequency; one Hertz corresponds to one cycle per second.

Achieving the required surgical effect by conducting high-frequency electrical current through the tissue The HF surgical generator and its connection cables. The path taken by the therapeutic current. HF surgical device - active electrode - through the body tissue - neutral electrode - HF surgical device and in another direction (alternating current circuit).

Destruction of tissue caused by the concentration of HF current. This expression also includes the surgical effect, but usually refers to unintentional tissue damage; see also unintentional burns.

Frequencies at which radio signals can be transferred; here the high-frequency current used for HF surgery.

Resistance in the alternating current circuit, the ohmic resistance and the resistance generated by capacity or inductivity. The resistance of a material measured in ohms is its tendency to withstand the flow of current or, in other words, the tendency of a material not to conduct the current. HF device technology using a feedback circuit to scan the tissue resistance. The resistance of the target tissue can vary, so that the computer-controlled output voltage of the HF surgical device is automatically adjusted in certain modes. The result is a constant output power which achieves the same surgical effect in all tissue types.

Introduction or injection of gas, steam or powder into body cavities or organs (e.g. carbon dioxide in the abdominal cavity during a laparoscopy). Output of an HF surgical device which has no connection to the earth potential.

Material which does not conduct electric current.

This condition occurs when the insulation around an electrical conductor is damaged. The result can be that the current flows outside the intended current circuit.

Characteristic of a current circuit to transfer an electric charge from one conductor to another, even if these are separated by insulation. Transfer of energy from one conductor (the active electrode) through the intact insulation into adjacent conductive material (tissue, trocars, wires, etc.).

Clotting of blood or destruction of tissue without incision effect; HF surgery differentiates between desiccation and fulguration.

Intermittent high-voltage wave mode which has been optimised for HF surgical coagulation.

Surgical procedure for coagulating bleeding blood vessels, where the active electrode makes contact with the forceps/clip: the current passes through the vessel forceps to the target tissue. This procedure is a form of contact coagulation.

Insulated container for safe storage of the active HF electrode when not in use during the operation. Recommended to avoid accidents. Transfer of electric power between two neighbouring circuits. Condition of a HF surgical circuit when the high-frequency surgical device is activated and the active electrode has direct contact with the neutral electrode. An electrical circuit without load (consumer).

In HF surgery, the body tissue which is included in the HF surgical circuit; the electrical impedance in this circuit.




Macro bipolar

Micro bipolar Monopolar HF surgery

Monopolar output

Monopolar instrument


Neutral electrode

REM contact quality monitoring system

Incision Cut

Self-restricting power Voltage

Voltage from peak to peak

Peak voltage

Spray Current

Current density Circuit

Current division


Quantity of energy produced per second, expressed in watt. Material which conducts electric current.

HF surgical excision procedure in gynaecology, where a loop is used to remove the transformation zone of the cervix (large loop excision of the transformation zone).

HF surgical wave mode used in bipolar surgery with higher voltage and power than the normal bipolar HF surgical wave modes. It is used for bipolar incision or fast coagulation.

Bipolar wave mode with low voltage used for precise desiccation. HF surgery procedure where the active electrode is in the surgical wound. One active pole.

Earthed or insulated output for a HF surgical device which conducts current through the patient to the neutral electrode.

HF surgical instrument or accessory consisting of just one electrode; one active electrode. Destruction of tissue.

Conductive surface in direct contact with the patient's skin during HF surgery. During the operation, it absorbs the HF current from the patient across a wide surface, distributes it and returns it to the HF surgical device, closing the circuit. Standard neutral electrodes today are disposable electrodes fixed with an adhesive gel.

Unit of measurement for electrical resistance; volt per ampere. Special Valleylab safety system which continuously monitors the impedance level between patient and neutral electrode. If the REM system registers dangerous impedance levels as a result of poor contact between the neutral electrode and the patient, the system produces an acoustic and optical signal and the HF surgical device is switched off. To guarantee maximum safety, HF surgical devices equipped with REM must use a compatible neutral electrode. This electrode can be recognised as having two separate areas and a special connector with a middle pin.

HF surgical effect resulting from high current density in the tissue causing intracellular fluid to evaporate. This results in the cell wall bursting with destruction of the cell structure. Low voltage, high current flow. Continuous low-current wave mode optimised for HF surgical incision. Power feature of the HF surgical device which limits the power output at certain tissue resistances.

Force pressed across the resistance by the electrical current; electromotor force or potential difference, expressed in volt.

The voltage of a wave mode, measured from its maximum negative value to its maximum positive value.

The maximum voltage of a wave mode, starting from zero (0) in a positive or negative direction to the maximum value.

Coagulation mode allowing for optimum fulguration.

Number of electrons passing a given point in a second, measured in ampere

Amount of current flow per surface unit; the current density is directly proportional to the heat generated in the material. Path along which the electric current moves.

Electrical current which leaves the intended HF surgical circuit and follows an alternative path with the least resistance to the earth potential; typically the cause for unintended burns at earthed HF surgical devices far from the operating site.

In HF surgical devices an electrical connection circuit which changes the ratio of current to voltage and converts wave modes with low voltage and high current into wave modes with high voltage and low current.

Burns under the neutral electrode HF surgical burns resulting from an excess concentration of current or current density under the neutral electrode. Volt (V) Unit of measurement for electrical potential (voltage).

Watt (W) Unit of measurement for power.

Wave mode Graphical representation of electrical activity; it shows how voltage varies with the change in current over time. Resistance Lacking conductivity of a material, measured in ohms.

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