The document discusses various energy sources used in surgery such as electrosurgery, electrocautery, bipolar electrosurgery, and ultrasonic devices. It explains the properties of electricity and how electrosurgical units work. The effects of different waveforms, power settings, and other variables on tissue are described along with safety considerations for different energy modalities.

1. ENERGY SOURCES IN
SURGERY
Dr Naveen Kumar A,
Dept. of General
Surgery,
MMHRC.

2. PROPERTIES OF ELECTRICITY
 Current = flow of electrons during a period of time.
 Voltage = force with which the electrons are
pushed through the tissue
 Impedence/Resistance = measure of the difficulty
that a given tissue presents to the passage of
electrons
 Circuit = Pathway for uninterrupted flow of
electrons.
 Power = Capacity to do work per unit time.

3. Standard electrical current: 60 Hz
Nerve and muscle stimulation cease at:
100KHz
An electrosurgical generator takes 60 Hz
current and increases its frequency to over
200,000 Hz

4. Electrosurgical Unit
 Converts a 60 cycles / sec (60 Hz), lowvoltage
alternating current into higher voltage radio
frequency (500 KHz - 3.0MHz) current.

5. Electrocautery is NOT Electrosurgery
 The terms electrocautery and electrosurgery are
frequently used interchangeably; however, these
terms define two distinctly different modalities.
 Electrocautery: use of electricity to heat an object
that is then used to burn a specific site e.g. a hot wire
 Electrosurgery: the electrical current heats the
tissue. The current must pass through the tissue to
produce the desired effect..

6. MONOPOLAR ELECTROSURGERY

7.  4 components: generator, active electrode, patient,
patient return electrode.
 Electrical energy flows from the generator (ESU
unit), to the active electrode (cautery pencil).
 The energy then passes through the patient to the
dispersive cautery pad, thus completing the electrical
circuit.

8. Effect of temperature on cells and tissue
 cellular temperature reaches 50°C cell death will
occur in approximately 6 min.
 if the local temperature is 60°C cellular death is
instantaneous.
 Between about 60 and 95°C two process occur
- first is protein denaturation -> coagulum
- dessication
 If the intracellular temperature rises to 100°C or
more – vapourization.
 local temperature reaches 200°C or more -
carbonization

9. TISSUE EFFECTS WITH WAVEFORM
MODIFICATION
 Cut waveform: Duty cycle(“on”
time) is high, continuous
waveform
 vaporize or cut tissue,
 Produce heat very rapidly
 Coagulation waveform:
intermittent waveform
 Duty cycle (“on” time) reduced,
 Produce less heat so coagulum is
formed
 Blended current : not a mixture
of cutting and coagulation, but a
modification of duty cycle

10. ELECTROSURGICAL TISSUE EFFECTS
 Cutting: divide tissue
with electric sparks that
focus intense heat at
surgical site
 -By sparking we achieve
maximum current
concentration
 Fulguration: sparking
with coagulation
waveform
 -coagulates and chars
the tissue over a wide
area, result in coagulum
 -high voltage coag
current is used(duty
cycle 6%)

11.  Desiccation: occurs
when electrode is in
direct contact with the
tissue
- -Achieved most
efficiently with cutting
current
- -by touching electrode
to the tissue, current
concentration reduced,
result in less heat and
no cutting action
- -cells dry out and form
a coagulum

12. VARIABLES IMPACTING TISSUE
EFFECT
 Waveform
 Power settings
 Size of electrode
 Time
 Manipulation of
electrode
 Type of tissue
 eschar

13. Patient return electrode
 The only difference
b/w active electrode
and patient return
electrode is their
relative size and
conductivity
 At patient return
electrode site:
reduced contact area-
current concentration
increased-
temperature
increased- burn

14.  REM contact quality
monitoring(RECQM)
 -protects patient from
pad site burn
 -monitor impedance at
the patient/pad
interface
 -system deactivate if
impedance is high
 -such electrode can be
identified by its split
appearance i.e. two
separate areas and a
special plug with
center pin.

15. ELECTROSURGICAL INJURY
Direct coupling
 occurs when the active electrode touches another
metal instrument.
 The electrical current flows from one to the other
and then proceeds to tissue resulting in unintended
burn.

16. Insulation failure
 occur when the insulation covering of an
instrument has been damaged.
 Cracks or breaks in the shaft’s insulation allow the
electrical energy to escape and burn unintended
tissue.
 Coagulation waveform is high in voltage, which
can spark through compromised insulation. Also high
voltage can blow holes in weak insulation.

17. Capacitive coupling
 During MIS procedure, an inadvertent capacitor may be created by
the surgical instruments.
 A capacitor creates electrostatic field created b/w two conductors,
resulting induced current in second conductor.
 Hybrid cannula are worst , metal part will create a capacitor but plastic
anchor will prevent the current from dissipating through abd wall.This
current may exit to some adjacent tissue, result in significant injury.

18. BIPOLAR ELECTROSURGERY
 The two tines forceps
function active and return
electrodes.
 Only the tissue grasped is
included in circuit.
 No patient return electrode
 Better hemostasis
 Less thermal injury
 Safer than monopolar

19. LIGASURE
BIPOLAR VESSEL SEALING DEVICE
 Electrosurgical technology
that combines pressure
and energy to create a
seal.
 Seals vessels up to 7 mm
with a single activation.
 Seal strength comparable
to sutures/clips, can
withstand >3 times normal
SBP.
 Lateral thermal spread :
0 - 4.5 mm

20.  Energy delivery cycle:
-measure initial resistance of tissue and chooses
appropriate energy settings
-delivers pulsed energy with continuous feedback
control
-senses that tissue response is complete and
stops the cycle.

21. HARMONIC ACE

22.  Electrical energy is passed to the hand piece
 Piezo-electric ceramic disks in hand piece
become excited
 Disks transfer electrical energy into mechanical
energy
 Reaches maximum frequency of 55,500
cycles/sec at blade tip

23.  Blade comes into contact with tissue, pressure
causes coaptation of blood vessel
- Hydrogen bonds are broken, protein in cells is
denatured
- Denatured protein forms a sticky coagulum
 allows for simultaneous cutting and coagulation
to take place at a lower temperature
 Can seal vessels upto 5mm

24. THUNDERBEAT
 THUNDERBEAT is
integration of both bipolar
and ultrasonic energies
delivered simultaneously
from a single versatile
instrument.
 benefits of each individual
energy; the ability to rapidly
cut tissue with ultrasonic
energy; and the ability to
create reliable vessel seals
with bipolar energy.

25.  Reliable 7 mm vessel sealing
·Minimal thermal spread
·Quickest in-its-class cutting
·Reduced mist generation for improved
visibility
·Fine dissection with fine jaw design