This document discusses different power sources used in surgery including electrosurgery, argon beam coagulation, cryotherapy, and ultrasound dissection. It explains that electrosurgery uses high frequency electromagnetic waves to heat and destroy tissue in a localized area depending on whether cutting or coagulation is needed. Argon beam coagulation uses an inert argon gas to conduct monopolar radiofrequency current to tissues to achieve hemostasis without direct electrode contact. Cryotherapy uses freezing temperatures to cause cell death by mechanisms like cold shock injury and destruction of tumor vasculature. Ultrasound dissection uses high frequency mechanical vibrations to fragment tissues.
2. Principles of Electrosurgery
• Electrosurgery means using of high-frequency
electromagnetic waves to produce a localized
heating of tissues, leading to localized tissue
destruction.
• The effect produced (cutting vs coagulation)
depends on how this energy is supplied.
3. ELECTROSURGERY
• Definitions:
1. An Electrical Circuit: الكهربية الدايرة
Any pathway that allows the uninterrupted flow of electrons.
2. Electrical current: الكهربائي التيار
The flow of electricity (the number of electrons) in a circuit over a
constant period of time and is measured in amperes (A).
3. Current can be supplied either as
Direct current (DC) with constant positive and negative terminals or
Alternating current (AC) with constantly reversing poles.
4. Voltage:
Measurement of the force that pushed the current of electrons and is
related to the difference in potential energy between two terminals.
4. 5. The resistance:
tendency of any component of a circuit to resist the
flow of electrons and applies to DC circuits.
6. Any electromagnetic wave
Can be described by three components:
Speed (constant as travel by speed of light),
frequency, and wavelength.
Since these three characteristics are defined by the
equation: c = fλ
frequency (f) and wavelength (λ) are inversely related;
that is, as frequency increases, wavelength decreases,
and vice versa.
5. The ability to pass high-frequency
current through the human body
without causing excess damage makes
electrosurgery possible
7. The electrosurgical circuit consists of
four primary parts:
1. The Electrosurgical Generator,
2. The Active Electrode,
3. The Patient, And
4. The Return Electrode.
N.B. Not monopolar (2 electrodes)
11. • The Essential Components of the bipolar
electrosurgical circuit are the same.
• However, the active and return electrodes are in
the same surgical instrument.
• High-frequency current is passed through the
active electrode === through the patient to
heat and disrupt tissue===the return electrode
on the opposite pole of the active electrode.
• This method enables the surgeon to heat only a
discrete amount of tissue
12.
13. The Electromagnetic Spectrum &
Tissue Effects
• The current of the electrosurgical generator is
supplied at a frequency of 60 Hz ===
produce strong neuromuscular stimulation
and heart stimulation in cardiac arrest.
• The current of the electrosurgical generator is
supplied at a frequency of 200 Hz known as
radiofrequency === produce serious RF
burns in focal lesions.
14. Types of Electrosurgery
A. Cutting:
• Depends on the production of a continuous
sine wave of current.
• Current flow 100% of the cycle
• Low voltage Produce Intense heat.
• Non-contact mode == vaporises and cuts.
• Contact mode == Dehydrate
15. B. Coagulation: Desiccation and
Fulguration
• Produce non continous wave of current.
• Current flow 6% of the cycle.
• High voltage.
• Sparks across agap to coagulate.
• Desiccation تجفيف
Direct contact of the electrode with tissue
• Fulguration صعق
The tip of the active electrode is not in contact with
the tissues
16.
17.
18. Disadvantages and Potential Hazards
• Alternate site burns— Buttock, knee, med.
And lat. malulous
• Surgical fires— flammable substances must be
kept away from heat sources.
• Direct coupling between the electrode and
other conductive instruments, leading to
inadvertent tissue damage.
VIDEO
19.
20.
21. Argon Beam Coagulation
• Principles:
1. Argon uses a coaxial flow of argon gas (inert
gas) as spray to conduct monopolar RF
current to the target tissue (Obtain
hemostasis).
2. Can operate only in two modes:
Pinpoint coagulation and Spray coagulation.
The method does not cut even the most delicate
tissue.
22.
23. Advantages
1. Allows use of the coagulation mode without
contact of the electrode prevent formation of
eschar.
2. Less smoke and less odor from coagulating
with this type of current.
3. Less Tissue loss and Tissue damage.
4. Reduces blood loss and the risk of
rebleeding.
24. Disadvantages
1. Cannot used to produce a cutting effect.
2. If used for a prolonged period of time, it may
overheat and cause damage and perforation.
25. Applications
• Suited to
dissecting very
vascular tissues
and organs, such
as the liver.
• Hemorraghe after
polypectomy,
After Radioation
proctitis and
angiodysplasia.
27. • A technique of in situ tissue ablation that uses
freezing temperatures to cause cell death.
• Used for cutaneous lesions, tumours of the
head and neck, cervix, rectum, prostate,breast
and liver.
• Used in irresectable or multiple liver
metastases from colorectal cancer.
28. Mechanism of action:
1. Cold shock injury
2. Reduction in cell volume by osmotic
dehydration
3. Denaturation of vital cellular enzymes.
4. Perforation of cell membranes by
intracellular ice crystals.
5. Destruction of tumour microvasculature
30. • Use high-frequency mechanical vibrations to
fragment tissue.
• Used in ophthalmic, neuro., hepato-biliary and
oncologic cytoreductive surgery.
• Fragments tissue by contact with high water
content cells – Vibration generate vapor
pockets within the cells that lead to disruption
and fragmentation.
