Various types of Energy Sources used in Surgery are discussed In this presentation,like Radio frequency ablation,Ultrasound Energy, Argon beam Coagulation etc Dr H V Shivaram, HOD-Surgery & Allied Specialties, Aster CMI Hospital, Bangalore

1. Energy Sources In Surgery
Dr Ritika Jha
Moderator –Dr H V Shivaram

2. 1. Introduction
2. History
3. Basic principles of electrosurgery
4. Radiofrequency electrosurgery
• Monopolar
• Bipolar
• Complications
5. Recent technologies

3. Electrosurgery
• Application of high frequency alternating polarity,electrical current to biological
tissue as a means to cut ,coagulate,fulgurate,dessicate tissue
• Electrocautery uses heat conduction from probe,heated to high temperature by
direct electrical current

4. History
• Becquerel (Early 19 th century) –first used Electrocautery
• D Arsonoval –pioneered use of Alternating current
• Late 1920:William T Bovie with Harvey Cushing :Electrosurgical
Generator
• In 1968 ,Valleylab developed smaller model,
produced today’s platform for electrosurgical
units

5. Basic principles of electrosurgery
• Ohm’s law
V = I x R

7. Electrical circuit
• 3 Components
1. Electrosurgery generator
2. AC current
3. Tissue Effect

8. Electro surgery generator
• Electromagnetic generator takes 60 Hz current and converts its frequency over
20,0000 Hz
• Nerve and muscle stimulation cease at 100 KHz
Current
AC current:
No net flow of electrons
Less chances of electrocution

9. Thermal effects at tissue level
To and fro motion
of electrons
Electrical energy
converted to
kinetic energy
Kinetic energy
converted to
thermal energy

10. • Thermal Change =𝑘 𝑥( 𝐽)2𝑥 𝑅 𝑥 𝑇
• J is Current Density = Current /Surface Area
• R is Resistance
• T is Time
• Heat generated depends on :
1. Power/frequency setting of current
2. Length of activation time
3. Waveform:continuous/intermittent
4. Contact area

11. CUT
• Low voltage + Long duration
• Produce heat rapidly
COAGULATE
• High Voltage + Short duration
• Produce less heat ,so coagulum
formation

12. Dessication
• Electrode in direct contact with tissue
• Achieved with cutting current
• Current concentration reduces on
direct contact,less heat,no cutting
action
• Cells dry out and form coagulum
Fulguration
• Sparking with coagulation waveform
• Coagulates and chars the tissue over
wide area,result in coagulum
• High voltage coagulation current is
used

13. Radiofrequency Electrosurgery
• Monopolar • Bipolar

14. Monopolar Electrosurgery
• Most commonly used electrosurgical modality
• 4 COMPONENETS:
1. Generator
2. Active electrode: in wound
3. Patient
4. Return electrode: attached some where on patient
• Produce tissue effects based on waveforms

15. Variables impacting tissue effect
• Waveforms
• Power settings
• Size of electrode
• Time
• Manipulation of electrode
• Type of tissue

16. Generator
Ground Electrosurgical System
Current passes through patient and
returns to generator ,which is linked to
ground.
Disadvantage:
Current goes to any grounded object
other than patient return electrode and
cause alternate site burns.
Isolated Electrosurgical Unit
Circuit completed by generator,not by
ground
Patient return electrode is recognized as
preferred pathway
Hazards of current division and alternate
site burn eliminated.Isolated circuits do
not protect from return electrode site
burn
Return electrode burn occurs when heat
produced ,overtime,is not safely
dissipated by size or conductivity of
patient return electrode

17. • Active electrode
-Entry site
-Used to
Cut
Blend
Coagulate
Dessication
Fulguration

18. Advantages
• Convenient
• Multiple modalities
• Adjust current density
• Inexpensive
• Easily available
• Best method for simple incisions on
skin
Disadvantages
• Interference with pacemakers during
surgery
• Higher temperatures at tool tip and
longer time to cool
• Large thermal spread

19. • Active Electrode and patient return electrode:
Difference is between surface area and conductivity
• Return electrode monitoring system:
- Protects patient from pad site burn
- Monitor impedance at patient/pad interface
- System deactivate if impedance high
- Electrode identified by split appearance :two separate areas and special plug with
center pin

20. Bipolar Electrosurgery
• Short circuit established between tips of instrument
• Tissue between two electrodes heated and dessicated
easily
• Best for coagulation
mainly for small vessel coagulation

21. Advantages
• Better control
• Risk of patient burns reduced
• Used in patients with implants
• Good for coaptive vessel sealing
Disadvantages
• Operation time longer
• Not as effective on small blood vessels

23. Complications Mechanical
injury
Dispersive
electrode
Application
site issue
Partial
detachment
Current
Diversion
Insulation
failure
Direct
Coupling
Active electrode
injury
Inadvertent
activation
Direct
extension

24. Insulation Failure
Break/defect in insulation coating of instrument
Cause:
Excessive use of instrument
Frequent Mechanized sterilization
Prevention:
Decrease current concentration
Coagulation with cutting current
Use of Active electrode monitoring system

25. • Direct Coupling
Electrosurgical unit accidentally
activated if active electrode is in
contact with other metal
instrument

26. • Capacitative Coupling
Electrical current in tissue/metal instrument running parallel but not in direct
contact.
Prevention:
o Metal trocars
o Electrode monitoring system
o Limiting time for which high voltage
setting used
o Large diameter trocars with smaller
diameter electrodes

27. Newer Technologies
Active electrode monitoring systems
Monitor and shield against stray electrosurgical currents when interfaced with
electrosurgical units
Minimise risk of insulation failure,capacitative coupling
Tissue response generator
Computer controlled tissue feedback system senses tissue resistance,a consistent
electrosurgical effect obtained through all tissues types

28. Vascular Sealing Technology/Ligasure
• Based on bipolar electrosurgery relying on tissue response generators
• Electrical current with mechanical pressure delivery by instrument to fuse vessel
wall
• High current,low voltage denature elastin and collagen
• Mechanical pressure allows denatured protein to form coagulum
• ENERGY DELIVERY CYCLE:
o Measures initial resistance of tissues and choose appropriate energy settings
o Delivers pulsed energy with continuous feedback control
o Senses tissue response complete ,stops cycle

29. • Vessels upto 7 mm and large tissue bundles can be ligated
• Advantage:
• Decrease operating time,blood loss
• Feedback controlled output so reliable seal.Seal strength comparable to
sutures/clips
• Lateral thermal spread is less
• Disadvantage:High cost

30. Ultrasonic energy system
• Ultrasonic >20,000 Hz
Ultrasonic wave
Transmit
through
solid/liquid
Mechanical
energy

31. • Employs compression and friction to deliver mechanical energy to target tissue
• Amino acids unwind and Hydrogen bond break to form coagulum
• Ultrasonic shears contain piezoelectric discs ,which convert electric energy to
mechanical energy
• Instrument blade vibrates at 55000 Hz
• Coagulates and transect vessels upto 3 mm(recent instruments can do upto 5mm)

32. • 2 Cutting mechanisms of harmonic scalpel:
1) Cavitational cutting and Fragmentation
2) Actual power cutting by large blade vibrating at 55,000 times/sec

33. Ultrasonic Generator
• Minimum setup: Power 5 = 50 micron displacement
• Maximum setup: Power 1 = 100 micron displacement
• We can set power set up from 1 to 5

34. Tissue effects
• Cutting
• Coagulation
• Cavitations
• Drilling

35. • Advantages
• Less heat produced
• No transmission of active current ,so
eliminate risk of electric shock
• Disadvantages
• Slower coagulation
• Not efficient to seal vessels >3 mm size
• High blade temperatures and can
damage adjacent tissues after being
switched off
• Aerosolized fatty droplets produced
which effect visualisation through
laparoscope

36. ULTRASONIC LIGASURE MONOPOLAR
Coagulation YES YES YES
Small vessel coagulation YES NO -
Large vessel coagulation No YES -
Cutting YES NO YES
Lateral thermal effects LOWEST MEDIUM HIGHEST

37. Thunderbeat
• Integration of both Bipolar and ultrasonic energies
delivered from single versatile instrument
• Adv:Ultrasonic:rapidly cut tissue
• Bipolar energy:ablity to create vessel seals

38. Advantages:
• Reliable 7 mm vessel sealing
• Minimal thermal spread
• Quickest class cutting
• Reduced mist generation
• Fine dissection
• Fewer instrument changes

39. Energy
system
Visiblity Operation
time
Thermal
spread
Thunderbeat Unimpaired Fastest in class
cutting
Least
LVSS Smoke
production
Slow 2mm
HS Mist
production
Slower Less than 1
mm

40. Argon Beam Coagulation
Mechanism:
Direct beam of Argon gas from electrode tip used in conduction of radio frequency
current to tissue by ionisation
Advantage:
Faster coagulation system
Uniform and shallower coagulation region
Faster dispersion ,less tissue damage

42. • Advantages
1. Most effective haemostasis
2. Faster coagulation
3. Argon blows away blood and debris
from coagulated surface ,making
more uniform
4. Less smoke
5. Constant thermal spread (2-3 mm)
• Disadvantages
1. Argon beam embolism
2. Mostly for coagulation

43. Transmission of infection and prevention
• MODE OF TRANSMISSION:
1. SURGICAL SMOKE
2. AEROSOLIZED BLOOD
3. ELECTRODE
Possilble transmission:Hepatitis B
Virus,HPV,Staph aureous
• Prevention
1. Smoke evacuating system to be
used
2. Face mask
3. Protective eye ware
4. Disposable electrodes

44. THANK YOU