This observation has been supported by the many litigations I have been involved in either as a defendant or, more frequently, an expert witness. Thus, I feel obligated to draw your attention to using correct language so that all concerned understand and mean the same thing.
Electrosurgery is the cutting and coagulation with high-frequency, alternating currents. Regrettably, the terminology in common use is not standardized, which often leads to misunderstandings, confusion and accidents. The following are the more common terms used in this specialty.
- Electrobisection: correct terminology for cutting with RF-currents (HF-currents).
- Electrohemostatis: Correct terminology for the sealing of small vessels and capillaries with RF-currents, employing forceps, ball, blade and other large surface electrodes.
- Electrocoagulation: Correct terminology with similar meaning as electrohemostatis. It also includes tissue destruction with RF-currents before excavation, used in tumor surgery.
- Cautery: The correct definition of it is the tissue destruction with the "hot iron," including galvanic cautery. This technique is antiquated. The word cautery is commonly, but incorrectly, used, meaning electrosurgery and primarily electrocoagulation.
- Fulguration: Correct terminology for surface coagulation, produced by a sparking of RF-currents between the point of an active electrode and the tissue surface.
- Desiccation: Describing a technique by inserting a fine needle into the skin with a RF-current discharge.
- "Cold" coaguluation: Electrocoagulation with a smooth, non-modulated RF-current, employing coagulation electrodes such as clamps, balls, etc. This term is used because, if proper equipment and technique are employed, it produces coagulation without visible sparking between the active electrode and the tissue. This is contrary to the technique with spark-gap, or other modulated currents.
- "Hot" coagulation: Electrocoagulation with modulated RF-currents such as spark-gap, TESLAR, etc., employing all kinds of electrodes, including cutting electrodes. The term is used because there is a significant sparking between the active electrodes and the tissue. Fulguration is frequently included under this terminology.
- "Cold" cutting: Electrobisection with smooth, non-modulated RF-current. Little or no sparking between the cutting electrode and the tissue is visible.
- "Hot" cutting: Electrobisection with a modulated RF-current such as blended or mixed currents. This technique produces cuts with pronounced coagulation. Sparking between the cutting electrode and the tissue is visible.
RF-Generators and Their Common Terminology
- Bovie: Trademark of one specific electrosurgical unit. The term is frequently, but incorrectly, used to describe electrosurgical units of other manufacturers.
- Lesion generator: Electrosurgical unit
- Surgical diathermy: Electrosurgical unit
- RF-generator: Electrosurgical unit
- Cautery: Electrosurgical unit
- Tube generator: Produces non-modulated smooth RF-current with frequencies between 1.0- and 3.0 MHZ (long wave).
- Spark-gap generator: Produces modulated RF-currents of wide band frequencies and amplitudes. Voltages up to 15,000 volts.
- Solid state generator: Electrosurgical unit with the transistor oscillator replacing tubes and spark-gap components.
RF-Currents and Their Terminology
- Cutting current: Non-modulated smooth RF-current with frequencies between 0.5 and 3.0 MHz (long wave current). Produces smooth cuts ("cold" cutting) with cutting electrodes such as needles, lancets, loops and knife electrodes and coagulation ("cold" coagulation) with coagulation electrodes such as balls, blades, forceps, etc.
- Spark-gap current: Modulated RF-current of wide band amplitude and frequency. Produces "hot" coagulation with all kinds of electrodes, particularly cutting electrodes (provided by outdated equipment).
- Mixed or blended: Mixture between tube and spark-gap currents suitable for cutting with more or less heavy coagulation, respectively, produced by solid state generators.
Current
- TESLAR current: Suitable for fulguration and desiccation.
Regrettably, most of these terms are used incorrectly. Radio frequency (RF) current is often mentioned as something new, which is untrue. It is the same as high frequency (HF) current, meaning electrosurgical currents. The following parameters are important as to performance:
- Frequency: 0.5 to 3 MHz
- Waveform: Sinusoidal or modulated
- Peak-to-peak voltage: May range from 100 to 1,500 V
- Output impedance: May range from 50 to 500 Ohm
- Output compensation: Automatic or manually regulated
- Unipolar vs. bipolar output: Unipolar (or monopolar) employs a large patient electrode (patient plate) and a relatively small active electrode (needle, lancet, snare, forceps, etc.); in the bipolar circuit, both electrodes have to be of similar size and equal impedance is primarily used for bipolar sealing of bleeders.
Another criterion is the output design:
- Isolated: The current flows between two equally sized electrodes, such as in a bipolar circuit; or
- Monopolar application: Small active and large inactive electrodes are used. The RF-current is isolated from earth ground.
Ground referenced output, or capacitively grounded circuit, is only for unipolar applications because the neutral electrode is capacitively grounded, which means ground referenced.
Karl Hausner has served as the president of ELMED, Inc., since 1969. With a formal background in education in the natural sciences, he has conducted workshops with universities, primarily with emphasis on electrical safety in surgery, including publications and lectures. He was also a member of the board of Siemens Medical.
For more information, visit: www.elmed.com or to request the booklet "Introduction to Electrosurgery," write: ELMED, Inc. 60 W. Fay Ave. Addison, IL. 60101