Electrosurgery

Electrosurgery - Shocking Science Stuff

• Uses high-frequency (HF) alternating current (0.5 - 4 MHz) to cut, coagulate, desiccate, or fulgurate tissue. Avoids neuromuscular stimulation (faradic effect < 100 kHz).
• Tissue Effects: Depend on waveform, power, time, electrode.
  • Cutting: Continuous waveform; rapid heating, vaporization.
  • Coagulation: Interrupted waveform; slower heating, protein denaturation.
  • Fulguration: Non-contact sparking; superficial charring.
  • Desiccation: Direct contact; deeper tissue dehydration.
• Modes:
  • Monopolar: Current path: active electrode → patient → dispersive (grounding) pad.
    • ⚠️ Risk: Grounding pad burns if poor contact/small size.
  • Bipolar: Current confined between two closely spaced electrode tips. No grounding pad needed; generally safer.
    • Preferred for delicate tissues & patients with pacemakers.
• 📌 Cutting Continues (Continuous waveform for cutting).

⭐ Bipolar electrosurgery is generally preferred in patients with cardiac pacemakers or implantable cardioverter-defibrillators (ICDs) to minimize electromagnetic interference and current diversion through the device lead system.

Electrosurgery - Zap That Lesion!

Utilizes high-frequency AC ($> \textbf{100}$ kHz, typically 0.5-2.5 MHz) for controlled tissue destruction or cutting via heat.

• Modes:
  • Monopolar: Active electrode delivers current; patient completes circuit via dispersive plate. Risk of burns if poor contact.
  • Bipolar: Current confined between electrode tines. No dispersive plate. Safer for pacemakers/ICDs.
• Waveforms & Tissue Effects:
  • Damped (interrupted, high voltage): Dehydration, coagulation. For desiccation, fulguration, coagulation.
  • Undamped (continuous): Vaporization, cutting. For electrosection.

⭐ In electrosection, a pure "cutting" current (fully filtered, undamped) produces the least lateral heat damage, ideal for obtaining biopsy specimens with minimal thermal artifact.

Electrosurgery - Handle With Care!

Electrosurgery uses high-frequency electrical current for cutting, coagulation, desiccation, or fulguration. Safety is paramount.

• Key Safety Principles:

  • Dispersive Electrode (Return Pad):
    • Large, well-vascularized area (e.g., thigh).
    • Avoid bony prominences, scars, metal implants.
    • Ensure full, firm contact. ⚠️ Prevents burns.
  • Pacemakers/ICDs:
    • Bipolar mode strongly preferred.
    • Monopolar: short bursts, lowest power, orient current path away from device. Cardiology input.
  • Flammable Agents: Ensure alcohol preps are completely dry.
  • Smoke Evacuation: Mandatory; smoke contains carcinogens, irritants.

• Common Modes:

  • Monopolar: Active electrode delivers current; passes through patient to dispersive pad.
    • Cutting: Continuous waveform. Coagulation: Interrupted.
  • Bipolar: Current confined between instrument tips. No dispersive pad. Safer for delicate areas, pacemakers.

• Potential Complications:

  • Burns (active or dispersive site).
  • Surgical smoke hazards.
  • Fire/Explosion (rare).
  • Electromagnetic interference with devices.

• Contraindications:

  • Absolute: Patient refusal.
  • Relative: Pregnancy (cautious use, avoid pelvis/fetus).

⭐ Bipolar electrosurgery is generally safer in patients with pacemakers/ICDs as the electrical current is confined between the instrument tips, minimizing systemic passage.

High‑Yield Points - ⚡ Biggest Takeaways

• Electrosurgery utilizes high-frequency alternating current for tissue destruction (e.g., cutting, coagulation).
• Monopolar mode requires a dispersive (patient return) electrode; current passes through the patient.
• Bipolar mode confines current between two active electrodes; safer, no dispersive plate needed.
• Cutting current is continuous (undamped); coagulation current is intermittent (damped waveform).
• Fulguration creates a spark to superficial tissue; desiccation dehydrates tissue via direct contact.
• Key risks include burns, pacemaker interference (especially with monopolar), and surgical smoke hazards.