Electro-Surgery in laparoscopic surgery

RCMC.BASIC LAPAROSCOPIC COURS

Dr.Medhat M. IbrahimConsultant pediatric surgeryand Minimal access surgery.

IntroductionMany energy sources are avilable to:Cut,Coagulate,evaporate tissue ,The objective of this study is; understanding the energy source

Basic electro-surgical circuit – (Monopolar)

Surgeon

Source - Gen

Patient

Return cable/path

Active cable/PathPower supply

Patient Return Electrode

High current density at the narrowing of an electrical conductor creates heat

220 Volt 50 Hz

Tissue on plate is part of the circuit

Active Electrode

High current density= heat development in tissue

Low current density / No heat development in tissue

Return Electrode

220volt/50Hz

Why not 50 Hertz

Alternating current at frequencies from

1 to 100,000 Hertz will interfere with the neuro-muscular system.

Above 100,000 Hertz these stimuli occur too quickly to affect the neuro-muscular system.

350 KHz to 3.3 MHzElectrosurgery

HouseholdPurposes

NeuromuscularStimulation ceases

AM Radio FM Radio

TV

50 Hz 550 Khz1550 Khz 54 – 880 MHz

100 Khz

Below 100 Khz – Electrical shock Above 100 Khz - No electrical shock

What it does?

Vapourises

& De-Hydrates

across almost all tissue types

Basic electro-surgical circuit - Monopolar

Source - Gen

Patient

Return cable/path

Active cable/Path

SurgeonPower supply

Patient Return Electrode

Vaporization & De-Hydration

Cut/Vaporization:

High current concentration at active electrode causes

intense heat in tissue (above 100c)

Coagulation (Dessication)

Intermittent supply of current to a larger electrode

causes less intense heat into tissue (below 100c),

allows heat dispersion

Coagulation

Cut

Energy

Intense Energy

Dehydration through heating

Coagulated cell

Cell expands through increase in pressure

Exploded cell

Wave forms

pure cut blend cut desiccation fulguration

Pure cut uses the lowest level of voltage

Monopolar Electrosurgery

Cut

Pure Blend

Coagulation

Fulguration Dessication

Pure cut Blend Fulguration/non contact coag

Dessication 1

Dessication 2

Dessication 3

Spray coagulation or fulguration

Blade electrode

Bleeding vesselPrinciple:Current followsPath of leastresistance

Limiting power settings by limiting contact

Blade electrode Micro Needle electrode

Choice of electrode & technique determines tissue effect

Forceps - tips

The electrosurgical effect is influenced by:

1. Contact Time

2. Power Settings of Generator

3. Type of electrode used (Current Density)

4. Whether Cut or Coag activated

5. Tissue Impedance

6. Distance from Active to Return

Bipolar electrosurgery in egg white/glass

Bipolar Forceps coagulation

SalineCorrect

Correct

Incorrect

Incorrect

Some Issues

Usually, a very safe device to use, however, these machines are often seen as the most

hazardous device used in an OR!

WHY?

The patient return electrodeGeneral rules for safe practice

Minimally Invasive Surgery issues

Pad site burns are prevented by assuring optimal conditions at the pad-patient

interface.

High current concentration/density

Low current concentration/density

Pad site burns are caused by adverse conditions at the pad-patient interface

which result in increased current density.

Current density increases when– current removal area is too small– heat is applied for too long – power setting is too high

High current concentration/density

Plate Burns !!!

A burn under the patient plate is

ALWAYS

negligence

Monitoring Current

RF Current

RF Current

Basic rules

1. Position plate as close as possible to surgical site

2. Check contact of plate throughout procedure

Avoid the following patient plate locations

Scar tissueMetal implantsPacemakersBony structuresMonitoring electrodesAreas of moisture concentration

Glove burn (“Bovie-bite”)

Result glove burn

!!Whoops???

Causes of glove burn Activation of fulgurate or spray output High power settings Surgeons technique

Open circuit activation

Removal of forceps whilst activating

Carbonisation causes higher leakage current due to increased resistance

Quality of gloves

Recommendation: Use Cut or Dessicate

Other Complications

• Bowel gas ignition

• Staple line/clip conductivity

• Current Density Complications

• Prep fluid

Electrosurgery Safety Considerations for

Minimally Invasive Procedures

Direct Coupling

LaparoscopeView

Active Electrode

MetalInstrument

Telescopewith Camera

Bowel

Insulation Failure

Electrode Insulation Failure

Abdominal Wall

Electrode Tip

Laparoscopic View

Metal Trocar Cannula

Bowel

Insulation Failure

Thermal injury caused by Insulation Failure of electro-surgical instrumentduring Laparoscopic Cholecystectomy

Intended Current Flow

Induced Current

Metal CoilConductor

Air(Insulator

Metal CoilConductor

Capacitor

Capacitance Increases with Use of

– Longer instruments– Higher voltages– Narrower diameter

cannulas

L

Instrument/Metal Cannula ConfigurationCreating a Capacitor

Abdominal Wall

Conductor(Electrode Tip)

Insulator (Electrode Insulation)

Laparoscopic View

Conductor (Metal Cannula)

Instrument/Plastic Cannula Configuration

Can capacitive coupling occur?

Abdominal Wall

Conductor(Electrode Tip)

Insulator (Electrode Insulation)

Laparoscopic View

Insulator (Plastic Cannula)

Instrument/Hybrid Cannula ConfigurationCapacitively Coupled Fault Condition

Capacitively Coupled Energy to Metal Cannula

Electrode TipBowel

Plastic Collar

Energy dispertion

Energy Dispertion

Hybrid Trocar/Cannula System

You make one yourself.

Conclusion

Electro-Surgical devices can be a potential hazard in an Operating Room.

However, they can also be very safe,

its always the driver in control!