The Effect of Electrosurgery on Tissue

April 22, 2019

According to recent literature, electrosurgery is used for cutting and coagulating tissue in eight out of ten (80%) surgeries performed today.1 In fact, the use of electrosurgery is so common in the operating room, that sometimes clinicians take it for granted. Reviewing the basics of the effect of electrosurgery on tissue is the first step to understanding the more complex devices and issues facing today’s perioperative team: Electrosurgical Units (ESU), Advanced Energy, Smoke Evacuation and other topics.

The way electrosurgical devices create the effect they have on tissue is by creating heat. Even though some of the more modern surgical energy devices are not necessarily thought of as “cautery”; they still work by creating heat, including ultrasonic energy, laser energy, and plasma energy.

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Tissue responds in different ways to the heat generated by electrical currents:

1. “Vaporization: Tissue is vaporized when heated rapidly to 100°C or more in the cut mode. Steam generated during this process explodes tissue cells to create this cutting effect. Thermal spread is minimal if the active electrode is held just above the target tissue and kept in a constant, controlled motion.
2. Fulguration: Occurs when tissue is heated above 200°C, which carbonizes cells and creates coagulation that starts hemostasis. When done correctly using the coagulation (coag) setting, fulguration results in wide, shallow cuts.
3. Desiccation: Holding the active electrode in cut mode against tissue dries and collapses cells when the tissue is heated to 90°C. Using the coag setting for this purpose results in more thermal spread.”2

Patient related electrosurgical risks can cause poor outcomes and be a major cost to the healthcare system. Thermal spread, a major patient risk, is defined as direct application or damage to adjacent tissue and occurs when the heat generated spreads beyond the tissue that the surgeon intends to treat. Thermal heat depends upon voltage which is associated with Vpeak, the peak of the voltage during the duty cycles of cut and coag. This maximum voltage potential is what can lead to thermal spread.

There are two ways to minimize thermal spread via the relationship between lower voltage and Vpeak:

1) Operate the ESU at the lowest power setting possible to achieve the desired effect.
2) Purchase an ESU the provides optimal power at less Vpeak than otherwise similar generators.

Surgeons have an effect on the tissue as well. The surgeons choose between cut, coag, and other specialized settings.

1. CUT: The first clinical mode of a modern ESU. Electrosurgical “CUT” requires less pressure than actual scalpel. Two types of cutting:
a. Pure Cut: Dissection only, instrument performs like a scalpel.
b. Blended Cut: Adds some hemostatic effect, seals off small bleeders.

2. COAGULATION (COAG): The second clinical mode of a modern ESU. Used for hemostasis. Two types of coagulation:
a. Coagulation (pinpoint): Surgeon holds the electrode in physical contact with the tissue. Time of contact is important. Stops local bleeding. Cell necrosis is limited to surface layers of tissue.
b. Fulguration (spraying): Non-contact coagulation, current sparks or jumps from the active electrode to the tissue. Effective for sealing hidden bleeders and for areas with large bleeders. Used to destroy surface layers of cells in the bed where a suspicious lesion has been removed –will prevent possible migration of suspicious cells.

3. CHARRING/ESCHAR: Can be prevented with good technique. Secret is to keep electrode moving! It is very rare not to have some charring. DO NOT CLEAN ESCHAR with a SCALPEL BLADE!


1. Lee J. Update on electrosurgery: New products and features make procedures safer, easier. Outpatient Surgery Magazine 2002. electrosurgery–02-02.
2. Cook D. Playing It Safe with Electrosurgery. with-electrosurgery–07-11.

About the Author

Marilyn Burns Marilyn Burns
Director of Clinical Affairs & Medical Education at Symmetry Surgical®
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