Introduction

Forms of diathermy

Surgical uses & Types of diathermy

Complications

Diathermy, form of physical therapy in which deep heating of tissues is accomplished by the use of high-frequency electrical current.

The term diathermy is derived from the Greek words “Therma”, meaning heat, and “Dia”, meaning through.

Diathermy literally means “Heating through”. Carl France Nagelschmidt, a German

physician, in 1909 coined the term diathermy.

Depending on the amount of heat generated, diathermy can be used to merely warm or to destroy tissue.

In the first instance, it is particularly beneficial in relieving muscle soreness and sprain.

In the second, as an adjunct to surgery, diathermy is used to coagulate, prevent excessive bleeding, and seal off traumatized tissues.

It is particularly effective in eye surgery, neurosurgery & dermatology.

3 forms of diathermy - wide use in hospitals :

Shortwave

Ultrasound

Microwave

In shortwave diathermy, the part to be treated is placed between two condenser plates, and the highest temperature is concentrated in the subcutaneous tissues.

It is usually prescribed as treatment for deep muscles and joints and is sometimes used to localize deep inflammatory disease.

It uses high-frequency acoustic vibrations; their heating effect ↑ circulation and metabolism and speeds up the rate of ion diffusion across cellular membranes.

During treatment the apparatus is moved slowly across the surface of the area to be affected.

Ultrasound is used to heat selected muscles that are too deep to be significantly affected by surface heating.

Microwave diathermy uses radiation of very high frequency & short wavelength similar to radar waves.

All physiologic responses are due to its heating effect.

Microwave diathermy is used in the management of superficial tumours with conventional RT & CT.

Surgical diathermy is usually better known as "electrosurgery". (It is also referred to occasionally as "electrocautery“)

Electrosurgery and surgical diathermy involve the use of high frequency A.C. electrical current in surgery.

Diathermy can be used for 3 purposes :

Coagulation – Sealing of blood vessels.

Fulguration – the destructive coagulation of tissues with charring.

Cutting – used to divide tissues during bloodless surgery.

MONOPOLAR

BIPOLAR

Where electrical current passes from one electrode near the tissue to be treated to other fixed electrode (indifferent electrode) elsewhere in the body.

Usually this type of electrode is placed in contact with buttocks or around the leg.

Active electrode in surgical site.

Patient return electrode – electrical plate – attached elsewhere.

Current flows through patient.

Localised heating at tip of instrument.

Minimal heating on plate as more surface area.

Bipolar, where both electrodes are mounted on same pen-like device and electrical current passes only through the tissue being treated.

Advantage of bipolar electrosurgery is that it prevents the flow of current through other tissues of the body and focuses only on the tissue in contact.

This is useful in microsurgery and in patients with cardiac pacemaker.

Explosion

Burns

Lap.surgery

Sparks from diathermy can ignite any volatile or gases or fluid within the theatre.

Alcohol based skin preparation can catch fire if they are allowed to pool or around the patient.

Faulty application of the indifferent electrode with inadequate contact area.

Patient being earthed by touching any metal object.

Faulty insulation of diathermy leads.

Inadvertent activity such as accidental activation of foot pedal.

Diathermy of wrong structure becoz of lack of clarity of vision.

Faulty insulation of any lap instrument. Intraperitoneal contact of diathermy

with another metal instrument. Inadvertent activity while tip is out of

vision of the camera. Retained heat in the tip – touching the

bowel.

Short circuit instances leading to electrocution

Interfere with pacemaker function

Channeling effects if used on viscus with narrow pedicle (e.g. penis or testis)