Electrosurgery and curettage — Viva

Q1: Physics and definitions (2 min)

What is electrosurgery? How does it differ from electrocautery? Explain monoterminal versus biterminal circuits.

Expected answer: Electrosurgery delivers high-frequency RF current through tissue; resistive heating causes desiccation, fulguration, coagulation, or cutting. Electrocautery uses a heated metal tip without a patient electrical circuit. Monoterminal systems use a single active electrode with capacitive return through the patient (hyfrecator-style desiccation/fulguration). Biterminal systems add a large dispersive pad so current path and deeper coagulation/cutting are controlled.^[2]

Q2: Modalities (2 min)

List the four classical modalities and give one dermatologic use for each.

Expected answer: Electrodesiccation — contact dehydration for skin tags, C&E base. Electrofulguration — non-contact spark for superficial char. Electrocoagulation — vessel sealing after snip/shave/excision. Electrosection — cutting waveform for incision when an electrosurgical generator is used. Power settings are device-specific.

^[2]

Q3: C&E technique and selection (3 min)

When is electrodesiccation and curettage appropriate for BCC? Walk through the procedure and its histologic limitation.

Expected answer: Selected low-risk primary BCC — well-defined, non-aggressive histology, typically smaller lesions on trunk/extremities — not high-risk face, recurrent, or infiltrative disease. Technique: anaesthetic, dry field, curette to firm dermis, desiccate base/rim, repeat 1–3 cycles, dress, follow up. Curettings may confirm diagnosis but cannot provide complete orientated margin assessment; Mohs/excision are required when margin control matters.^[2]

Q4: Safety (3 min)

What fire and implantable-device precautions do you take?

Expected answer: Alcohol prep must dry completely; avoid sparking in oxygen-enriched fields; use plume evacuation when available. For pacemaker/ICD: history every time; prefer bipolar; short bursts; keep energy path away from generator/leads; monitor or seek cardiology input if high risk; hyfrecation is not universally interference-free.

^[1]

Q5: Critical pitfall (2 min)

A colleague wants to hyfrecate a dark irregular changing nodule. Your response?

Expected answer: Refuse destructive treatment. Changing irregular pigmented lesions are melanoma until proven otherwise. Destruction forfeits histology and staging. Dermoscopy now; excisional biopsy with appropriate narrow margins. This is the single most dangerous misuse of office electrosurgery.^[2]

References2ShowHide

1. [1]Amin SD, Homan KB, Assar M, et al. Hyfrecation and Interference With Implantable Cardiac Devices Dermatol Surg, 2020.PMID 31652225
2. [2]Taheri A, Mansoori P, Sandoval LF, et al. Electrosurgery: part II. Technology, applications, and safety of electrosurgical devices J Am Acad Dermatol, 2014.PMID 24629362