BY: DR RAM RAKSHA PALFNB(MAS) RESIDENT

Energy devices in

surgery

HISTORY

Use of electrocautery (FIRE DRILL)is

described in ancient medicine ,3000

BC

In 1881, morton: electric current in

100,000 Hz does not produce shock

Bovie made first electrosurgical

generator

BASICS OF ELECTRICITY

TEMPERATURE VS TISSUE EFFECTS

45 degree C: collagen uncoils & may reanneal; covalent bonds b/w edges and fuse

60 degree C: irreversible protein denaturation, coagulation necrosis begins; blanching

80 degree C: carbonization begins; drying and shrinkage of tissues

90-100 degree C: complete cellular destruction by vaporization; plume of gas and smoke

125degree C: complete oxidation of protein & lipids; carbon residue & eschar formation

Standard electrical current: 60 Hz

Nerve and muscle stimulation

cease at: 100KHz

An electrosurgical generator takes

60 Hz current and increases its

frequency to over 200,000 Hz

ELECTROCAUTERY IS NOT ELECTROSURGERY

The terms electrocautery and electrosurgery are

frequently used interchangeably; however,

these terms define two distinctly different

modalities.

Electrocautery: use of electricity to heat an

object that is then used to burn a specific site

e.g. a hot wire

Electrosurgery: the electrical current heats the

tissue. The current must pass through the tissue

to produce the desired effect..

MONOPOLAR ELECTROSURGERY

MONOPOLAR ELECTROSURGERY

Most commonly used electrosurgical

modality.

The active electrode is in the wound.

Patient return electrode is attached

somewhere else on the patient.

4 components: generator, active electrode,

patient, patient return electrode

Produce variety of tissue effects depending

on waveform

TISSUE EFFECTS WITH WAVEFORM MODIFICATION

Cut waveform: Duty cycle(“on” time) is high,

continuous waveform

vaporize or cut tissue,

Produce heat very rapidly

Coagulation waveform: intermittent waveform

Duty cycle (“on” time) reduced,

Produce less heat so coagulum is formed

Blended current : not a mixture of cutting and

coagulation, but a modification of duty cycle

Only variable that determine

vaporization or coagulation is rate of

heat

High heat, more rapidly : vaporization

Low heat, more slowly : coagulum

ELECTROSURGICAL TISSUE EFFECTS

Cutting: divide tissue with

electric sparks that focus intense

heat at surgical site

-By sparking we acheive maximum

current concentration

Fulguration: sparking with

coagulation waveform

-coagulates and chars the tissue

over a wide area, result in coagulum

-high voltage coag current is

used(duty cycle 6%)

ELECTROSURGICAL TISSUE EFFECTS

Desiccation: occurs when electrode is in direct

contact with the tissue

--Achieved most efficiently with cutting current

--by touching electrode to the tissue, current

concentration reduced, result in less heat and no

cutting action

--cells dry out and form a coagulum

We can cut with coag current and

coagulate with cutting current.

Benefit of coagulating with cutting

current is that we use far less voltage.

it has important implications in MIS

VARIABLES IMPACTING TISSUE EFFECT

Waveform

Power settings

Size of electrode

Time

Manipulation of electrode

Type of tissuecurrent flow is greatest in tissues of high water content, such as blood, and least in those of low water content, such as bone

Eschar

ELECTROSURGICAL GENERATORS

two types of electrosurgical generators:

• Ground referenced generators (typically

older, outdated units)

• Isolated generators (today’s state-of-art

technology)

GROUNDED ELECTROSURGICAL SYSTEMS

The current passes through the patient and returns to the generator, which is linked to ground.

The problem is the current can go to any grounded object other than the pateientreturn electrode (ECG electrodes, OR bed, metal objects) and cause alternate site burns.

outdated technology

Current division:

ISOLATED ELECTROSURGICAL SYSTEM

In 1968,isolated generator technology

revolutionized electrosurgery

Circuit is completed by the generator, not

by ground

Current does not recognize grounded

objects as pathways to complete the

circuit

Patient return electrode is recognized as

preferred pathway

Hazards of current division and alternate

site burn are eliminated.

ISOLATED ELECTROSURGICAL SYSTEM

Generators with isolated circuits do not

protect from return electrode site burn

A return electrode burn occurs when the

heat produced, over time, is not safely

dissipated by the size or conductivity of

the patient return electrode.

PATIENT RETURN ELECTRODE

The only difference b/w active

electrode and patient return electrode

is their relative size and conductivity

At patient return electrode site:

reduced contact area- current

concentration increased- temperature

increased- burn

surface area impedance can be

increased by excessive hair, adipose

tissue, bony prominences, fluid

invasion, adhesive failure, scar tissue

PATIENT RETURN ELECTRODE MONITORING TECHNOLOGY

REM contact quality monitoring(RECQM)

-protects patient from pad site burn

-monitor impedance at the patient/pad

interface

-system deactivate if impedance is high

-such electrode can be identified by its split

appearance i.e. two separate areas and a

special plug with center pin.

INSTANT RESPONSE TECHNOLOGY

SAFETY CONSIDERATIONS DURING MIS

Direct Coupling

occurs when the active electrode touches another metal instrument.

The electrical current flows from one to the other and then proceeds to tissue resulting in unintended burn.

This can also occur if an active electrode is activated while in contact with a metal clip.

So, do not activate the generator while the active electrode is touching a metal object or not in vision.

INSULATION FAILURE

Insulation failure can occur when the insulation covering of an endoscopic instrument has been damaged

Cracks or breaks in the shaft’s insulation allow the electrical energy to escape and burn unintended tissue.

The insulation of endoscopic instruments must be inspected before, during and after each use

Most damage to insulation occurs during instrument processing, specifically during sterilization. Heat with subsequent cooling causes insulation to shrink and then expand. During this process cracks and breaks can occur.

INSULATION FAILURE

Coagulation waveform is high in

voltage, which can spark

through compromised

insulation. Also high voltage can

blow holes in weak insulation.

We can get the desired

coagulation effect without high

voltage , simply by using the

‘cutting’ current by holding the

electrode in direct contact with

tissue

CAPACITIVE COUPLING

During MIS procedure, an inadvertent capacitor may be

created by the surgical instruments

An electrostatic field created b/w two conductors,

resulting induced current in second conductor

Hybrid cannula are worst , metal part will create a

capacitor but plastic anchor will prevent the current

from dissipating through abd wall.This current may exit

to some adjacent tissue, result in significant injury

Use the lowest power setting

Use the lower voltage setting such as “Cut,” rather than

“Coag” or “Spray Coag.”

Keep the electrode eschar free

Use larger diameter trocars and smaller diameter

electrodes

ACTIVE ELECTRODE MONITORING

shielded and monitored instruments continuously direct stray energy, away from the patient via a protective shield.

When insulation failure occurs or capacitively coupled energy reaches dangerous levels, the electrosurgical unit (ESU) shuts down automatically and the surgical staff are alerted.

AEM system detects even the smallest full thickness insulation breaks on Laparscopic instruments, virtually eliminating accidental burns due to faulty insulation, saving costs and reducing the possibility of patient injury.

BIPOLAR ELECTROSURGERY

The two tines forceps

function active and return

electrodes.

Only the tissue grasped is

included in circuit.

No patient return electrode

Better hemostasis

Less thermal injury

Safer than monopolar

RECOMMENDATIONS TO AVOID

ELECTROSURGICAL COMPLICATIONS IN MIS

Inspect insulation carefully

Use lowest possible power settings

Use a low voltage waveform(cut)

Use brief intermittent activation vs prolonged

activation

Do not activate in open circuit

Do not activate in close proximity or direct

contact with other instrument

RECOMMENDATIONS TO AVOID

ELECTROSURGICAL COMPLICATIONS IN MIS

Use bipolar electrosurgery when

appropriate

Do not use hybrid canula. Select an all

metal canula system as the safest

choice.

Active electrode monitoring system: to

avoid problems of insulation failure and

capacitive coupling

VESSEL SEALING TECHNOLOGY

•Combination of pressure and energy

to create a seal.

•Feedback controlled output so

reliable seal in minimal time

•Seals vessels up to 7 mm with a

single activation.

•Seal strength comparable to

sutures/clips, can withstand >3 times

normal SBP.

•Lateral thermal spread :

-ligasure: 0 - 4.5 mm

-enseal trio: 1 mm

VESSEL SEALING TECHNOLOGY

•Applies optimal pressure to vessel

•Energy delivery cycle:

-measure initial resistance of tissue and

chooses appropriate energy settings

-delivers pulsed energy with continuous

feedback control

-senses that tissue response is complete

and stops the cycle.

ULTRASONIC ENERGY DEVICES

Ultrasonic shears employ both compression and friction to deliver mechanical energy to target tissue

Amino acids unwind and reshape and hydrogen bonds break resulting in sticky coagulum

Ultrasonic shears contain piezoelectric diskes, that converts electric energy into mechanical energy which is amplified by silicone element

Instrument blade vibrate at 55500 hz along the long axis

Safely coagulates and transect vessels upto 5 mm

ULTRASONIC ENERGY DEVICES

• provide excellent hemostasis, efficient

transection, minimal lateral thermal damage,

low smoke generation, and no risk of

electrical current passage to the patient.

• optimization of the energy delivery during

application can improve them further

HARMONIC ACE+ SHEARS

The new Adaptive Tissue

Technology

achieving better control of

energy delivery to the tissue,

seals vessels with supra-

physiological burst pressures,

low thermal damage.

THUNDERBEAT

THUNDERBEAT is

integration of both bipolar

and ultrasonic energies

delivered simultaneously

from a single versatile

instrument.

benefits of each individual

energy; the ability to rapidly

cut tissue with ultrasonic

energy; and the ability to

create reliable vessel seals

with bipolar energy.

THUNDERBEAT

THUNDERBEAT provides

unprecedented

versatility, including:

· Reliable 7 mm vessel

sealing

· Minimal thermal spread

· Quickest in-its-class

cutting

· Reduced mist generation

for improved visibility

· Fine dissection with fine

jaw design

· Fewer instrument

exchanges Revolutionary

jaw design

ARGON ENHANCED ELECTROSURGERY

CAVITRON ULTRASONIC SURGICAL ASPIRATOR(CUSA)

CUSA is a dissecting device that uses ultrasonic

frequencies to fragment tissue.

Utilizing a hollow titanium tip that vibrates along its

longitudinal axis, fragmentation of susceptible tissue

occurs while concurrently lavaging and aspirating

material from the surgical site.

The CUSA selectively ablates tissues with high water

content such as liver parenchyma, glandular, and

neoplastic tissue.

This instrument is most useful when removing

purportedly “non-resectable” brain and spine tumors.

With a gentle wand-like motion, the CUSA enables a

“layer by layer” surgical excision without affecting vital

structures