Breif description of monopolar, Bipolar, Thunderbeat, Harmonic, Ligasure.

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