Electrosurgery
Electrosurgery uses high-frequency alternating current (radiofrequency, RF, from 300 kHz to 4 MHz) to cut, coagulate or vaporize diseased tissue. It differs from electrocautery, which uses direct current to heat a metal tip that then transfers heat to the skin indirectly. In electrosurgery, the patient's own tissue acts as the resistor, converting electrical energy into heat inside the cells so the lesion can be treated precisely.
The Four Electrosurgical Techniques
Depending on voltage, current, waveform and how the electrode contacts the skin, electrosurgery falls into four basic techniques:
- Electrodesiccation: A monopolar electrode touches the lesion directly and delivers a markedly damped waveform at high voltage and low current. Water inside the cells evaporates and the cells shrivel, making it suitable for superficial epidermal lesions.
- Fulguration: The monopolar electrode is held 1–2 mm above the lesion. The current sparks across the air gap, causing broad but shallow necrosis without penetrating deep into the dermis.
- Electrocoagulation: A bipolar electrode, or a monopolar one with a dispersive pad, delivers a moderately damped waveform at low voltage and high current. The rapid temperature rise coagulates tissue proteins and denatures collagen, effectively sealing vessels under 1 mm in diameter.
- Electrosection: Uses a continuous, undamped high-frequency current (3.8–4.0 MHz). Cell water vaporizes instantly along the electrode's path, giving a clean cut comparable to a scalpel, with the added benefit of hemostasis.
Clinical Indications for Electrosurgery
| Lesion Group | Typical Lesions | Technique Used |
|---|---|---|
| Superficial benign lesions | Syringoma, skin tags, seborrheic keratosis | Electrodesiccation |
| Vascular lesions | Spider angioma, cherry angioma, telangiectasia | Electrocoagulation |
| Infectious lesions | Common warts, molluscum contagiosum | Electrodesiccation with curettage |
| Excision / sampling | Removal of dermatofibromas and hypertrophic lesions | Electrosection |
Safety Measures and Risk Control
- Fire safety: Antiseptics containing 70% alcohol or ether must be wiped dry and fully evaporated before any current is applied. The procedure is never performed near flammable gases such as oxygen.
- Patients with implanted electronic devices: Monopolar current can interfere with pacemakers and implantable cardioverter-defibrillators (ICDs). In these patients, we switch to bipolar electrosurgery or electrocautery, and position the dispersive pad so current does not pass through the heart.
- Managing surgical plume: The smoke produced contains fine particles, toxic chemicals and viable viral DNA (such as HPV). Staff must use a dedicated smoke evacuator with a ULPA filter and wear N95 or FFP3 respirators.
- Limiting thermal spread: Holding the electrode in one spot too long (more than 2 seconds) lets heat spread into the deep dermis, which can lead to depressed or hypertrophic scars.
