Electrosurgery Notes

Terminologies

• Monopolar = 1 tip at the end of surgical electrode
• Bipolar = 2 tip at the end of surgical electrode
• Monoterminal = Use of treatment electrode without ground plate (indifferent electrode)
• Biterminal = Both treatment and indifferent electrodes (ground plate) are used

Electrosurgery modalities

Modality	Electrode configuration	Waveform	Indications	Remarks
DC
Electrocautery			Patients with ICDs and pacemakers	No current passes through patient (direct heat transference to tissue)
AC		Unaltered sine wave
a. High voltage, Low ampere				Can be tolerated in patients with pacemakers at low dosage
Electrodessication	Monoterminal	Markedly damped	Superficial tissue destruction	Probe directly contacts tissue
Electrofulguration	Monoterminal	Markedly damped		Probe held far (spark effect)
b. High ampere, Low voltage				Cannot be tolerated in patients with pacemakers
Electrocoagulation	Biterminal	Sine wave – 6% on and 94% off	Deep tissue destruction	Higher contact surface area Lower impedance Lower current density
Electrosection (pure cut)	Biterminal	Sinewave – 100% on	Cutting	Vaporization Lower contact surface area Higher impedance Higher current density
Blend (coagulation + cut)	Biterminal	Sine wave – different proportions of on/off	Hemostasis + Cutting

Mnemonic: ABC

1. Ampere high
2. Biterminal
3. Coagulation, Cut, Coagulation + Cut (blend)

Mnemonic: VMDeF

1. Voltage high
2. Monoterminal
3. Dessication
4. Fulguration

Complications

Mnemonic: ABCDE

1. Active electrode trauma: inappropriate contact or inadvertent activation

2. Blaze (fire): near alcohol source or oxygen

3. Current diversion: ACID

• Alternate ground site burns
• Capacitive coupling: Transfer of current between 2 conductors (electrode tip and metal cannula) separated by insulator through the electrostatic field (reduced by plastic cannula instead of metal cannula); risk increased with –
  • High voltage (coagulation mode)
  • Open activation (electrodes not in contact with tissue)
  • Increased impedance (wrapping of cable around metal clamps like towel clip or activation over previously coagulated tissue)
• Insulation failure: Mainly with high voltage coagulation; smaller the break in insulation, higher the density of current dispersed
• Direct coupling: Transfer of current from one conductive source to another

4. Cardiac pacemaker: Interference from electromagnetic current; reduced by using –

• Bipolar electrode
• Short bursts of monopolar electrode
• Application of dispersive electrode as far as possible from pacemaker
• Immediate deactivation and activation of ICD preoperatively and postoperatively respectively

5. Dispersive electrode burns

• Loss of contact of electrode with patient
• Inappropriate application of electrode on bony prominences or adjacent to ECG leads

6. Explosions: in the vicinity of inflammable gas under pressure

Further reading: Complications, Implications, and Prevention of Electrosurgical Injuries: Corner Stone of Diathermy Use for Junior Surgical Trainees – PMC (nih.gov)