Dr Yogesh NikamGynaecologist

Laparoscopic & Robotic SurgeonMBBS, FRANZCOG, Master of Surgery (Obstetrics & Gynaecology)

Diploma in Advanced Endoscopic Surgery, Germany

Diploma in Gynaecological Endoscopy, BEAMS

Sydney West Advanced Pelvic Surgery, AU

VMO Norwest Private | Westmead Private | SAN Hospital

VMO Westmead Public | Staff Specialist (O&G), WSAHS

Senior Lecturer – UWS & Sydney University

Electro surgery in Gynaecology

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History

“Heat cures when everything fails” …Hipocrates. Albucasis (980BC) used hot iron to stop

bleeding. Then followed use of electrical current on a

metallic element…. just burns the tissues. But modern electro surgery or “Surgical

Diathermy” entails passage of high frequency electrical current through tissues.

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History

Earliest recorded use of this technology was by Arsenne d’ Arsonval in1893.

However extensive use of electro surgery in brain surgery by Harvey Cushing & William T. Bovie and their publication in 1925 promoted Electrosurgery.

They described three distinctive effects Desiccation Cutting Coagulation

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Electro cautery and Electro surgery

Electro cautery Direct current

through a high resistance metallic conductor

It is essentially application of heat and burning of tissue

Electro surgery High Frequency Alt.

Current through living tissue

Manipulation of electrons to produce heat within the cells to destroy the tissue

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Basics of Electricity

Two types of Current- Direct Current (DC) Alternating Current (AC)

DC flows continuously in one direction AC flows in two directions, first increasing

to a maximum in one direction & then increasing to a maximum in the opposite direction in a sinusoidal wave form.

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Basics of Electricity

Alt.Cur. has a positive & a negative peak.

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Alternating Current

Alt.Current can be generated in Three types of wave form:-

1) Continuous / Uninterrupted / non-modulated wave form (CUT) :-

Produced by continuous delivery of energy

2) Interrupted / Modulated / Dampened / Varied wave form (Coagulation):-

when energy is delivered only 10% of the time

3) Blended wave forms:- Produced by delivering energy at variable intervals,

which can be controlled / varied thus producing both effects

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Alternating Current

Continuous / Uninterrupted / non-modulated

Produced by continuous delivery of energy

Current flows 100% of the time the pedal is pressed

CUT

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Alternating Current

COAGULATION- Interrupted / Modulated / Dampened / Varied wave form

COAG

current is delivered only 10% of the time

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Alternating Current

Blended wave forms:-Produced by delivering energy at variable

intervals, which can be controlled / varied thus producing both effects

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The Machine (Generator)

It produces the required type of electricity in the patient circuit by induction from the supply line.

It has been undergoing constant improvement. 1st. Generation- Tungsten contacts. 2nd.Generation- Valve Generators. 3rd. Generation- Transistor technology. 4th. Generation- Digital Electronics technology. Latest- Microprocessor controlled diathermy,

User programmable, auto functions, error detection, safety alarms & cut offs.

Constant power delivery Under water application, soft & spray coagulation and

bipolar cut possible.

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Effect of Electricity on Living Tissue

Electrolytic Effect Faradic Effect Thermal Effect

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Electrolytic Effect

Produced by DC/ AC of very low frequency (<5kHz).

Electrolytic effect used in current induced drug transport…ophthalmology.

Undesirable in HF Electrosurgery

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Faradic Effect

Produced by AC of >20 kHz Stimulation of nerve & muscle cells –

Undesirable Can be avoided by using current of >300kHz

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Thermal Effect

Produced with AC >300kHz At this frequency Electrolytic & Faradic effect

are eliminated Tissue gets heated leading to three

possibilities, depending on- Current density, Duration of application & Specific resistance of the tissue.

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Thermal Effect: - Possibilities

Electrosurgical Cutting with / without Coagulation Desiccation Coagulation / Fulguration

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Thermal Effect: - Possibilities

440C Tissue Necrosis Starts

700C Coagulation begins with protein denaturation.. ”white coagulation”

900C Cells loose water content, tissues dehydrate but architecture is preserved…..desiccation

1000C Vaporization of boiled water starts…cells burst

2000C Carbonization starts…black eschar

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Electrosurgical Cutting

HF electricity raises tissue temperature very rapidly

Very rapid heating of cells No time for intra or extra

cellular fluid evaporation Steam formation-Pressure-

Explosive bursting of Cells With continuos current only

cutting

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Electrosurgical Desiccation

Tissue is gradually heated Water is slowly driven out Cell plasma coagulates Cut blood vessels shrink Bleeding stops Can be done with Needle electrode or bipolar

Coagulating Forceps.

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Electrosurgical Desiccation

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Bipolar Diathermy

Current flows locally through a small portion of tissue between two electrodes of the bipolar forceps

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Bipolar Diathermy

Advantages Technique is precise & safe for the patient. Preferred in endoscopic surgery. Unintentional burns avoided. Causes less disturbance to other electronic

equipments connected to the patient. Disadvantages

Only small amount of tissues can be handled. Cutting possible only with microprocessor

controlled machine.

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Monopolar Diathermy

High frequency current flows from the active electrode through the patient’s body to the patient plate.

It produces heat in the tissues proportional to the electrical resistance of the tissues and the current density.

Fatty tissues have a high resistance. Electrosurgical Cutting with / without Coagulation and

Desiccation / Fulguration all are possible.

Patient plate is required.

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Patient Plate

It is the negative pole / passive electrode through which the current returns to the machine after passing through the patient.

The current density at the patient plate is inversely proportional to the contact area.

A 50% decrease in contact area near the patient plate will produce two fold increase in current intensity and a four fold increase of heat.

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Patient Plate

Hence the Patient plate should be as large as possible.

It should be applied to a wide area of electrically more conductive tissues like muscles.

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Patient Plate

Current does not flow uniformly to the patient plate. Its density is higher at the corners and edges of the

patient plate nearer to the the active electrode. Hence the patient plate should be placed such that the

longer edge points to the active electrode.

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Patient Plate

It should make maximum and complete contact with the electrically conductive surface of the body to avoid burns.

Metal plates not to be used. Large Silicon rubber plates should only be used.

Simple patient plates are not so simplenot so simple..

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Conclusion

Modern diathermy is a versatile & useful surgical tool.

Advancements in the technology has opened up many new vistas in treatment.

Its proper & judicious use can not only benefit the patients but also will make the surgery more efficient, comfortable and simple.

However utmost care has to be taken during its use so as to avoid catastrophes.

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Electrosurgical Injuries

Secondary to thermal injuries Easily missed at time of injury Classified

1. Unintended thermal injury through the active electrode

2. Injury when the current is diverted to another path causing damage distant from the principal operative field

3. Injury at the site of the dispersive electrode

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Direct Coupling (out of view)

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Electrical Isolation(metal canula)

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Electrical Isolation(tissue)

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Sparking/Jumping

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Avoiding Electrosurgical Injuries

lower settings Keep probe in camera field

Check instruments for insulation

Metal vs... Plastic Trocars

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Harmonic Benefits

Minimal thermal tissue damage Greater precision near vital structures Less tissue charring and desiccation Minimal smoke for improved visibility Fewer instrument changes no electric current is sent through the

patient

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How does it work?

The electrical energy provided by the microprocessor-controlled Generator is converted into mechanical energy by the Hand Piece through a piezoelectric crystal system. The blade or tip of the instrument being used vibrates axially with a constant frequency of 55,500 Hz. The longitudinal extension of the vibration can be varied between 25 and 100 µ in 5 levels, by adjusting the power setting of the Generator.

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3 possible effects:

Cavitation Cavitation is achieved by the formation of vapor bubbles at

body temperature due to the rapid volume changes of the tissue and cell fluids, induced by the transmitted vibration to the tissues.

Coaptation /coagulation joint application of pressure and ultrasound to the tissue

fragments the protein compounds, leading to the adherence of collagen molecules at low temperatures

achieved at a temperature range of 37 °C to 63 °C Cutting

locally applied energy acts for longer periods, the rise in temperature leads to denaturing of protein – coagulation, at a maximum temperature of 150°C

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ULTRACISION HARMONIC SCALPEL Balance between Cutting and Coagulation

Cutting speed and extent of coagulation are easily controlled and can be balanced by varying four factors: Power Blade sharpness Tissue tension Grip force/pressure

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Power Setting

The Harmonic Scalpel generator has five power levels. Increasing the power level increases cutting speed and decreases

coagulation. In contrast, less power decreases cutting speed and increases coagulation.

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Blade Sharpness

Cutting speed is also a function of blade sharpness. The shear mode of the LCS cuts faster than the blunt mode; the blunt mode provides more coagulation, assuring coagulation when vascular tissue or vessels are encountered.

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Tissue Tension

More coagulation can be achieved with slower cutting when tissue tension is reduced. Increased tissue tension leads to faster cutting with less coagulation.

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Grip Force/Pressure

Grip force, or pressure, is another factor controlling the balance between cutting and coagulation. Application of a gentle force, or light pressure, achieves more coagulation with slower cutting. A firmer grip force achieves less coagulation with faster cutting.

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Hand piece of harmonic

Harmonic in action

4422/04/23 Courtesy : Ethicon Website

Monopolar in action in a da Vinci Robotic Surgery

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Bipolar in action in a da Vinci Robotic Surgery

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In summary In monopolar surgery, electrical current goes through the patient to complete

the current cycle, while

In bipolar surgery, the current only goes through the tissue in between the two electrodes of the instrument.

The cut mode on the electrosurgical unit generates a continuous, low voltage current concentrating the energy over a small area.

The coagulation mode on the electrosurgical unit generates an interrupted, high voltage current dispersed over a large surface area

Fulguration and vaporization are non-contact methods of monopolar electrosurgery, while desiccation/coagulation is a direct contact method of monopolar electrosurgery.

Vaporization results from rapid heating in the cut mode with intense vibration and heat within the cells, which causes the cell to explode and form smoke (plume)

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Fulguration is caused by an interrupted current (coagulation mode), causing slower tissue heating and less focused tissue effect.

The cut mode is preferred when thermal spread is undesirable, such as when the electrosurgical device is in close proximity to vital structures.

The coagulation mode is better suited for fatty tissue and scar tissue and when fulgurating a large surface area with superficial bleeding.

A return electrode monitoring system and active electrode monitoring are important safety tools during monopolar electrosurgery.

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Bipolar electrosurgery is ideal when dealing with vascular areas or large blood vessels, such as the uterine artery.

The disappearance of water vapor is a good guide for deciding when to stop the application of bipolar electrosurgical energy. Newer bipolar devices measure tissue impedance & stop the generator once the tissue is desiccated

The Ligasure had the best overall performance with the highest burst pressure, fast sealing time, low thermal spread, and low smoke production. Can be used on bigger vessels upto 7mm.

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The PK has a fast sealing time, high smoke production, variable and sometimes extremely low burst pressures.

The Harmonic Ace is a mechanical way to seal vessels. It has the lowest thermal spread and smoke production, but is slow and has low mean burst pressures. It is best used to seal vessels of 2-5mm of diameter.

A knowledgeable surgeon using an appropriate instrument at precise location for just adequate time is the best prevention against electrosurgical injuries.

Finally, Dr Andrew Bril put aptly at the AAGL conference

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It's not the magic wand, it's the magician!

THANK YOUTHANK YOU