3. 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.
4. 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.
5. 3 forms of diathermy - wide use in hospitals :
Shortwave
Ultrasound
Microwave
6. 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.
7. 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.
8. 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.
9. 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.
10. 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.
12. 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.
13. 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.
14.
15. 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.
19. 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.
20. 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.
21. 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.
22. Short circuit instances leading to
electrocution
Interfere with pacemaker function
Channeling effects if used on viscus with
narrow pedicle (e.g. penis or testis)
