Surgical Technology: Surgical Energy

Techniques/Instruments

Electrosurgery

  • Passes Electrical Current Through Tissue to Achieve a Desired Effect
  • Instruments:
    • Electrosurgery Pen/Pencil – Transmits Monopolar Energy
      • The Most Commonly Used Surgical Energy Form
    • Bipolar Forceps – Bipolar Energy Transmitted Between Tips
    • LigaSure – Uses a Combination of Pressure & Continuous Bipolar Energy
  • Terms “Bovie” & “Cauterize” are Often Mistakenly Used in Electrosurgery

Electrocautery/Bovie

  • Bovie is a Brand Name of a Tool Used to Cauterize Tissue
  • Passes Electrical Current Through a Wire to Heat at High Temperatures
  • Heated Wire Cauterizes (Burns & Coagulates) Tissue

Argon Beam

  • Monopolar Device
  • Argon Provides Electron Rich Medium for Superior Fulguration
  • Primarily Used in Liver Resection
  • Increased Risk of Gas Embolism

Ultrasonic Energy (Harmonic)

  • Ceramic Discs Create Mechanical Energy
  • Effects from Friction of Pressure from Vibrating Blades
    • Power/Energy Effect Fixed Blade Excursion (Not Voltage)
  • No Current Travels Through Patient

Radiofrequency Ablation (RFA)

  • Destroys Large Volumes of Tissue by Coagulation
  • Avoids Vaporization or Carbonization

Microwave Ablation (MWA)

  • Heat Transferred Outward from Antenna

Electrosurgery Pen

Electrocautery/Bovie

LigaSure

Argon Beam

Ultrasonic Energy (Harmonic)

Radiofrequency Ablation (RFA)

Microwave Ablation (MWA)

Electrosurgery Energy

Components & Electrodes

  • Electrosurgical Unit (ESU): Generates the Current
  • Active Electrode: Disperses Current into the Tissue (The Pen/Pencil)
  • Dispersive Electrode: Completes the Circuit & Returns Current from the Tissue (The Pad)
    • Pads are Wide to Disperse the Current Over a Wider Area & Prevent Injury at the Site
    • Not a “Grounding” Pad – Electrosurgery Works in an Isolated Circuit & Does Not Send Current to the Ground

Energy Waveforms

  • Cut
    • Types
      • Pure: Continuous Duty Cycle (100%)
      • Blend: Interrupted Duty Cycle (80%)
    • Lowest Voltage
  • Coag
    • Interrupted Duty Cycle (6%)
    • Highest Voltage
    • More Damage/Coagulation to Collateral Tissues

Polarity

  • Monopolar: Single Active Electrode
    • Energy Transferred from Active Electrode to Dispersive Electrode
  • Bipolar: Both Electrodes Active
    • Energy Transferred Between Tips
    • Minimizes Accidental Diversion
    • Can Seal Vessels ≤ 7 mm

Energy Waveforms 1

Thermal Energy Effects

60-95 Degrees C

  • Desiccation: Cell Loses Water
  • Coagulation: Protein Denaturation & Reformation
  • Seals Vessels

> 100 Degrees C

  • Vaporization: Cell Rupture from Massive Expansion Due to Steam
  • Cuts Through Tissue

> 200 Degrees C

  • Fulguration/Carbonization: Cellular Breakdown Forming Eschar
  • Good Superficial Coagulation
  • Best in Coag Mode (Risen Impedance Diverts to Zones of Less Impedance)

Accidental Thermal Injury

Direct vs Indirect

  • Direct Injury: Misidentification or Pilot Error
  • Indirect Injury: Current Conducted Along Unintentional Pathway

Indirect Injury

  • Insulation Failure
    • Break in Insulation of the Active Instrument Causes Conduction of Current to Unintended Tissues
  • Direct Coupling
    • Active Instrument Contacts Nonactive Instrument
    • May Be Intentional to Seal Vessels (Vessel Grabbed by Forceps)
      • Best in Cut Mode – More Even/Homogenous Seal
  • Capacitative Coupling
    • Field Around Active Conductor Transferred Through Insulation to Another Conductor (Scope/Cannula/Instrument)
    • Risk Factors: Parallel Alignment of Cords

Insulation Failure 1

Direct Coupling 1

Capacitative Coupling 1

References

  1. Alkatout I, Schollmeyer T, Hawaldar NA, Sharma N, Mettler L. Principles and safety measures of electrosurgery in laparoscopy. JSLS. 2012 Jan-Mar;16(1):130-9. (License: CC BY-NC-ND-3.0)