High Frequency Heat Theraphy

7/31/2019 High Frequency Heat Theraphy

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Electro surgeryin Gynaecology


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History Heat therapy known since antiquity

Heat cures when everything fails Hipocrates.

Albucasis (980BC) used hot iron to stop bleeding.

Then followed use of electrical current on a metallic

element.

This method just burns the tissues.

But modern electro surgery or Surgical Diathermy is

a recent technology, which entails passage of highfrequency electrical current through tissues.


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History

Earliest recorded use of this technology wasby Arsenne d Arsonval in1893.

However extensive use of electro surgery in

brain surgery by Harvey Cushing & William T.Bovie and their publication in 1925 promotedElectrosurgery.

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 metallicconductor

It is essentiallyapplication of heat

and burning of tissue

Electro surgery High Frequency Alt.

Current through

living tissue Manipulation of

electrons to produceheat 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 & anegative peak.


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Alternating Current

Alt.Current can be generated in Threetypes of wave form:-1) Continuous / Uninterrupted / non-modulated wave

form (CUT) :-

Produced by continuous delivery of energy

2) COAG- Interrupted / Modulated / Dampened /Varied wave form:-

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 botheffects


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Alternating Current

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

delivery of energy


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Alternating Current

2) COAG- Interrupted / Modulated / Dampened /Varied wave form:-. when energy is deliveredonly 10% of the time


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Alternating Current

3) Blended wave forms:- Produced bydelivering energy at variable intervals, whichcan be controlled / varied thus producing

both effects


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The Machine (Generator)

It produces the required type of electricity in thepatient 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 cutpossible.


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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(


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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

Tissue gets heated leading to three

possibilities, depending on-

Current density,

Duration of application &

Specific resistance of the tissue.

This is the effect for clinical use.


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Thermal Effect: - Possibilities

Electrosurgical Cutting with / withoutCoagulation

Desiccation

Coagulation / Fulguration


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Electrosurgical Cutting +/- Coagulation

Very rapid heating of cells

No time for evaporation

Steam formation- Pressure-

Cells burst

With continuos current only

cutting

With blended current - both

cutting & coagulation.


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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 MP Ball / Needle electrodeor 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 twoelectrodes 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 activeelectrode through the patients body to the patient

plate.

It produces heat in the tissues proportional to theelectrical resistance of the tissues and the currentdensity.

Fatty tissues have a high resistance.

Electrosurgical Cutting with / without Coagulationand Desiccation / Fulguration all are possible.

Patient plate is required.


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Patient Plate

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

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

A 50% decrease in contact area near the

patient plate will produce two fold increase incurrent intensity and a four fold increase ofheat.


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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 patientplate.

Its density is higher at the corners and edges of

the patient plate nearer to the the activeelectrode.

Hence the patient plate should be placed such

that the longer edge points to the activeelectrode.


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Patient Plate

It should make maximum and complete contactwith the electrically conductive surface of the

body to avoid burns.

Metal plates not to be used. Large Siliconrubber plates should only be used.

Simple patient plates are not so simple.


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Diathermy in Gynaecology- General

Use

During surgery ( Open & Laparoscopic) for Cutting &

Haemostasis.

Cutting is more precise.

Haemostasis is better achieved. Can be used in LSCS. No effect on the fetus.

Take care while working near vital structures.

Apply the point first , then switch on the current. Monopolar & or Bipolar can be used.


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Diathermy in Gynaecology- Specific Use

Benign Cervical Lesions-

CIN (LEETZ / LEEP)-

Tubal Sterilisation-

Ovarian Drilling in PCOD-

Endometriosis-

Laparoscopic Myolysis- Hysteroscopic surgery- TCRE, sub mucus

Myoma, Septum Resection


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Electro surgery for Benign Cervical

Lesions

Coagulation / Desiccation / Cutting can bedone as the case may be, using Monopolar

diathermy in the following conditions.

Erosion & Chronic Cervicitis - Avoidendocervix

Mild degree Cx. Tears

Amputation


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Electro surgery for CIN Known as Large Loop Excision of the Transformation

Zone (LLETZ) or LEEP (Loop Electrosurgical ExcisionalProcedure).

A wire loop electrode on the end of an insulatedhandle is powered by an electrosurgical unit.

The current is designed to achieve a cutting and acoagulation effect simultaneously.

Power should be sufficient to excise tissue withoutcausing thermal artifact.

The procedure can be performed under localanalgesia.

Treatment success reported varies from 91% to 98%.


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Electro surgery for Tubal Sterilisation

Tubal sterilisation is usually done either by

mini- laparotomy 0r laparoscopy with almost

equal results.

But laparoscopy requires more sophisticated

and expensive equipment and greater skills.

Laparoscopic sterilisation should usually be

done by a single puncture and use of

monopolar coagulation as described by

Wheeless [Wheeless 1992].


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Female Sterilisation methods

0

5

10

15

20

25

30

35

40

clip bipolar interval ring mono PPTL overall

Method

24.8

7.5

17.7

36.5

20.1

7.5

18.5

Probability

per

1000procedures

Ten-Year Cumulative Probability ofPregnancy (per 1000 procedures)


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Electro surgery for PCOD For PCOD, Laparoscopic Ovarian Drilling (LOD) by Diathermy is

cost effective than Laser vaporization. It is done by passage of 40 W current for 4 seconds in 4 places

on each ovary with a monopolar needle.

Advantages of ovarian drilling-

Sensitizes the ovary to F.S.H. Less monitoring than Gonadotrophin therapy.

Unifollicular growth, No risk of OHSS and multiple pregnancy.

Low rate of abortion.

One treatment may result in many ovulatory cycles.

Ovulation rate 70 80% in failed C.C. cases, Pregnancy rate 60%

To reduce periovarian adhesions liberal peritoneal lavageshould be done. Early second look laparoscopy and adhesiolysismay be required.


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Electro surgery in Endometriosis

During surgery for endometriosis, small and

multiple lesions on the peritoneum are better

dealt with electrocoaglation.

Care should be taken while working near vital

structures.

Though both monopolar and bipolar may be

used, bipolar is safer and preferable.


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Electro surgery for Myoma

Myolysis - involves delivering electric current

via needles (Monopolar) to a fibroid at the

time of laparoscopy.

It offers a better alternative to myomectomy

with minimal blood loss to deal with myomas

particularly multiple ones.


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Hysteroscopic Electro surgery-

Endometrial ablation - Tran Cervical Resectionof Endometrium (TCRE), with wire loop orroller ball is a simple office procedure.

It can be the first line of surgical treatment inMenorrhagia (DUB) and may avoid hysterectomy.

Other hysteroscopic electrosurgicalprocedures are -

Electrovaporisation of sub mucus Myoma.

Septum Resection


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Conclusion

Modern diathermy is a versatile & usefulsurgical 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 surgerymore efficient, comfortable and simple.

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

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High Frequency Heat Theraphy