Electrosurgery describes a range of techniques that use electricity to pass through the skin. The result is that the electricity generates heat destroying tissues. Different modalities are used for different situations.
Electrofulgration
Electrofulgration is ideally used to remove superficial lesions, particularly those that have a minimal blood supply. Lesions that are commonly treated with electrofulgration include skin tags, seborrhoeic keratoses, warts, xanthelasma, and dermatosis papulosa nigra (DPN).
Electrofulgration uses a high-voltage, low-amperage current through a sharp-tip mono-terminal electrode that is held 1-2 mm from the skin surface. This means that it is a non-contact procedure. This produces an arc of electricity resulting in superficial tissue dehydration and epidermal carbonisation. The carbon layer acts as an insulator minimising damage to deeper tissues such as the dermis. This means there is a minimal (but not a zero) risk of scarring, especially with lower power settings. Risks include superficial scarring and hypopigmentation (white areas).
Electrodessication
Electrodessication is similar to electrofulgration, except, the electrode comes into contact with the skin. This results in reasonably superficial dehydration and damage due to heating. Again, there is a minimal (but not a zero) risk of scarring with low-power settings. Scarring is expected to occur with higher power settings.
Electrodessication is often used in conjugation with curettage to treat superficial skin cancers.
Electrocoagulation
Electrocoagulation is normally used to control bleeding as part of a larger procedure such as a surgical excision or Mohs surgery. It is colloquially known as diathermy or bipolar (when used with two terminals). In contrast to electrofulgration, it uses a low-voltage, high-amperage current with two terminals. These electrical characteristics allow it to achieve haemostasis (control of bleeding) with minimal carbonisation. However, this does mean deeper tissue destruction meaning it is not ideal for the removal of lesions on the surface of the skin.
Nonetheless, it may still be used for vascular lesions on the skin surface as a higher current is normally required to stop bleeding. If used, it is important to realise that the risk of scarring is much higher.
Diathermy with implanted devices
Electrosurgery may interfere with implanted electrical devices such as pacemakers and implantable cardioverter-defibrillators (ICD), nerve stimulators, and cochlear implants. These devices are sometimes set to fire when they sense electrical impulses e.g., from the heart. Electrosurgery devices can sometimes cause these devices to trigger incorrectly.
Diathermy with pacemakers
Most modern pacemakers are designed to reduce the risk of interference. However, electrosurgery in close proximity to pacemakers can still trigger inappropriate pacemaker pulses although it is rare. All cases should be assessed on a case-by-case basis, and this may include consultation with your cardiac electrophysiologist. General guidelines include:
- Avoid surgery within 5-10 cm of a pacemaker. Measured interference occurs within 1cm of pacemakers when 10W is used for electrosurgery and 3 cm (20-30W).
- Use short bursts of electricity.
- Use bipolar forceps over monopolar electrodes.
If these guidelines are unable to be complied with, it may require temporarily switching off the sensing function and switching the pacemaker into a fixed-rate mode.
Diathermy with Implantable Cardioverter-Defibrillators
ICDs continually monitor a person’s heart rhythm and when an abnormal rhythm (arrhythmia) is detected it can respond by delivering an electrical shock (defibrillation) to terminate the abnormal rhythm which can be life-threatening. Electrosurgery can interfere with with the sensing function of ICDs causing them to malfunction including delivering inappropriate defibrillation.
ICDs will normally need to be deactivated prior to procedures requiring electrosurgery. This will be undertaken in consultation with your cardiac electrophysiologist.
References
- El-Gamal HM, Dufresne RG, Saddler K. Electrosurgery, pacemakers and ICDs: a survey of precautions and complications experienced by cutaneous surgeons. Dermatol Surg 2001; 27(4): 385-90. doi: 10.1046/j.1524-4725.2001.00287.x
- Weyer C, Siegle RJ, Eng GG. Investigation of hyfrecators and their in vitro interference with implantable cardiac devices. Dermatol Surg 2012; 38(11): 1843-8. doi: 10.1111/j.1524-4725.2012.02526.x
