Energy source in surgery

1. Energy sources in surgery
DR.UMA

2. Types of energy in operating room
• Monopolar radiofrequency energy
• Bipolar radiofrequency energy
• Ultrasonic energy
• Thunder beat
• Plasma energy
• Laser
• Radiofrequency energy abalation
• Microwave
• Radiosurgery
• Cryotherapy
• Photodynamic therapy
• CUSA
• Vessel ligation technology

3. History
• William bovie developed the first
electrosurgical device
• First usage started at 1926 at peter bent
bringham hospital in bostan
• Cushing first published series of 5000
neurosurgeries performed with an
electrocautery device by bovie

4. Electrocautery & Electrosurgery
• Electrocautery refers to direct current whereas
electrosurgery refers to alternate current
• During electro cautery current donot enter
patients body and only heated wire comes in
contact with tissue whereas in electrosurgery
patient is included in circuit and currents
enters patients body

7. Electrosurgery
• Electrosurgery is passage of high frequency
electric current through tissue to create a
desired clinical effect
• Basic principle of electricity is it seeks the
path of least resistance

8. Properties of electricity
• POWER(W)=VOLTS * AMPERE
• CURRENT(A)= VLOTS/ IMPEDENCE
• W= Energy produced over time
• V=pressure required to push electron
• A= rate at which electron flow
• Impedence = resistance to flow of
current(ohms)

9. Fundamental of electrosurgey
• In radiofrequency electrosurgery
electromagnetic energy is converted into
kinetic energy then to thermal energy
• Medium of current is high frequency AC
current as low frequency cause stimulation of
neuromuscular system causing fasciculations
• Because the frequency used is in excess of
300kHz they are called radiofrequency

10. • Galvanic effect:
– When direct current is used anions and cations
disperse towards their respective oppositely
charged electrodes and serves no medical
purpose
– Whereas AC current is applied they migrate
towards opposite poles but cannot maintain single
orientation within cell and they oscillate in
conjugation with differing polarity

12. • Faradic effect:
– When low frequency AC (20-30kHz ) is used It
cause depolarization & stimulation of nerve and
muscle causing fasciculation and pain
• when an high frequency alternating current is
applied across cell membrane, pulse duration is so
short that sodium and potassium channel is not even
opened and electromagnetic energy is converted into
mechanical energy then into thermal energy with the
help of friction forces

13. • Joules law:
– when an AC/ DC flows through the resistor heat is
generated (i.e)due to impedance provided to flow
of current & thermal energy is generated

15. Components of electrosurgery
• Radiofrequency electrosurgical generator or
unit ESU
• Electrosurgical radio frequency instruments
– Active electrode
– Dispersive electrode

16. Principle of diathermy
• When electric current pass through conductor
some of energy appears as heat and it
depends on:
– Intensity of current
– Waveform of current
– Electrical property of tissue through which energy
passes
– Relative size of two electrodes

17. Principle of monopolar
• Alternating current produced by generator
and passed to patient via an active electrode
which has a very small surface area
• Then the current passes through the tissue
and returns via a large surface plate back to
earth pole
• As surface area of electrode is small the
current produce heat at operative site

18. • The large surface area of patient plate spreads
the returning current over a wide and surface
area so it is less concentrated and produce
less heat

20. Principle of bipolar
• Two active electrodes are usually represented
by limbs of pair of diathermy
• Both forceps ends are active and therefore
current flows through them heats only the
tissue between them

21. Effects of diathemy
• Coagulation: sealing of blood vessel
– High voltage low current mode
• Fulguration: the destructive coagulation of
tissues with charring
– High voltage , low current mode
• Cutting: to divide tissue during bloodless
surgery
– Low voltage , high current

22. Tissue effects with waveform
modification
• Cutting
– Uses constant waveform
– Current flow is 100% of cycle
– Low voltage produces intense heat
– Contact mode cause dehydration of tissue
– Non contact mode cause vapourisation and
cutting

23. • Coagulation:
– Uses intermittent waveform so ‘on’ time( duty
cycle is reduced)
– Produce less heat
– Current flow 6% of cycle
– Uses high voltage low flow current

24. • Blend:
– Is not a mixture of both cutting and coagulation
– It is modification of duty cycle( on time)
– Duty cycle is progressively reduced from blend 1
to blend 3
– Low duty cycle produce less heat
– Blend 1 vaporise tissue with less hemostasis and
vicecersa

27. Variables impacting tissue effects
• Waveforms
• Size of electrode: smaller is the electrode the
higher the current concentration
• Time : the longer the generator is active more
heat is produced
• Manipulation of electrode: in contact or away
from tissue
• Type of tissue: which varies in resistance
• Eschar :electrodes free of eschar have enhanced
performance

28. Grounded electrosurgical system
• Originally generators used grounded current
• It was assumed that current entered the
patients body would return to ground
through patient return electrode
• But electricity will always seek path of least
resistance and as many conductive objects
touching patient , the current will enter this
pathway to ground leading to alternate site
burns

30. RF Current division
• The current may split and follow more than one
path to ground
• Patients are exposed to alternate site burns
• Reasons :
– Currents flows through easiest pathway
– Any grounded object not just generator complete the
circuit
– Surgical environment offers many alternate route
– If resistance of alternate pathway is least the current
flowing through this pathway is sufficient to cause
burns

31. Isolated electrosurgical system
• Isolated generators isolate the therapeutic
current from grounded by referencing with
the generator circuit
• Even though ground objects remain in OR
electrosurgical current from isolated
generators will not recognise these objects

33. Deactivated isolated system
• If the circuit to patient return electrode is
broken an isolated generator will deactivate
because current cannot return to its source
• Isolated system can mitigate alternate site
burns but donot protect from return electrode
burns

34. Return electrode
• They are not inactive or passive and the only
difference between active electrode and
return electrode is size and relative
conductivity
• The function of return electrode or dispersive
electrode is to safely remove current from
patients body
• The return electrode should present a large
and low impedence contact area to patient

35. • If the surface area is reduced or impedance of
contact is increased it results in burns
• When surface area is reduced large amount of
current is concentrated in small area produce
heat
• Impedance increases when it is attached to
hairy area, adipose tissue, bony prominence ,
scar tissue adhesive failure, fluid invasion

36. Return electrode monitering
technology
• Quality monitering to protect patients from
burns due to inadequate contact of return
electrode
• REM equipped generators actively moniter the
amount of impedance at the patient pad
interface
• The system is designed to deactivate before an
injury occurs if it detects dangerous level of
impedance

37. Bipolar diathermy
• Advantages :
– Precise
– Safe
– Used in endoscopic surgery
– Unintentional burns avoided
– Less distrubances to other electronic devices
connected to patient
•Disadvantage :
•Only small amount of tissue can be handeled
•Cutting possible only with microprocessor controlled machine

38. Complication of diathermy:
• Fire :
– For fire to occur 3 elements must be present
– Heat( surgical energy), fuel( alcohol based
preperation), oxygen
– Rescue patient or staff
– Alert- activate fire alarm
– Confine- isolate fire by closing doors
– Evacuate the incident room and entire surgical
suite

39. • Antenna coupling
– Radiofrequency energy from wire or cable of
monopolar device can transmit into air and
nearby conductors
– Prevention:
• separate active and dispersive electrodes from other
nearby wires
• Minimize voltage
• Avoid usage of monopolar in single incision laproscopic
surgery

40. • Insulation failure
– Most common cause of thermal injury
– Common in monopolar
– Prevention:
• Careful inspection of instrument prior to use
• Maximize visualisation of entire instrument during activation to
indentify abberent energy arcs
• Residual heat
– Is defined as increased instrument temperature after
energy activation is complete
– Causes injury to tissue when reapplied prior to complete
heat dissipation
– Prevention: resue after 5 seconds of cooling

42. • Direct application:
– Unintentional activation of device during device use
– Eg: when surgeon leans on monopolar it activates and
burns patient skin
• Interaction with electronic devices
– Radiofrequency energy transmitted through air interferes
with nearby monitering devises like ECG leads, implanted
cardiac devices
– Eg: during activatio of monopolar cardiac defibrilator
sensitize dysrythmia and administer shock
– Prevention:utilize low power and avoid use of energy
devise near or parallel to implantable devise

44. • Direct coupling:
– Intentional when surgeon touches monopolar to
forceps to coagulate a tissue
– Unintentional when it is not under vision
– Prevention: avoid contact with other conductive
instruments, have complete visualisation before
activation

46. • Capacitive coupling
• capacitance is stored electric charges
when two conductors are seperated by an
insulator
• the stored energy can be transferred
through intact insulation into nearby
conductors like bowel producing injury
• prevention:
– use of low voltage
– Avoid usage of combined plastic and metal lap trocars
– Maintain complete visualisation of instrument

48. Channeling
• Occurs if current passes through a narrow
channel or a pedicle to active electrode,
enough heat may be generated to coagulate
tissue
– Coagulation of penis in children undergoing
circumcision
– Coagulation of spermatic cord when the electrode
is applied for testis

54. Ultrasonic energy
• Converts low voltage energy into high-
frequency mechanical vibrations via
piezoeletric crystals
• Rapid vibrations generate friction that heats
tissues, degenerate proteins(coagulate) and
creates tissue seperations (cuts) at
temperature below boiling point

56. • Advantage
– minimal charring,
– decrease operative time,
– seal vasculature upto 3mm,
– excellent hemostasis,
– minimal lateral thermal damage,
– low smoke,
– no risk of electrical current passage into patient
• Disadvantage: high cost

57. Thunderbeat
• Integration of ultrasonic and bipolar energy
simultaneously from a single instrument
• Ability to cut tissue with ultrasonic energy and
ability to create reliable vessel seals with
bipolar energy
• Advantage:
– 7mm sealing
– Minimal thermal spread
– Reduces mist formation

58. Plasma energy
• Radiofrequency energy is applied is carried
into tissue by an inert gas (argon)
• Used for superficial coagulation of diffuse
bleeding tissue like liver and spleen
• Disadvantage : intravascular embolism of
insoluble argon resulted in cardiac arrest and
death

59. Laser
• Generates heat by focusing beam of light on
tissue
• Can be used for both cutting and coagulation
• Can be used in dental, opthal, cosmetic and
gynecological procedure
• Common type: argon, Nd-YAG
• Penetration : Nd-Yag>CO2>argon
• Drawback: high cost

60. Radiofrequency energy abalation
• Basic method: placing a electrode on target tissue
to transmit high frequency alternating current to
tissue @ 300-500kHz- where kinetic energy is
converted into heat
• Has built in sensor for automatically terminating
transmission of current at a particular set point to
prevent unwanted collateral damage
• Used in tumor of liver, pancreas, thyroid, breast,
bone

61. Microwave abalation
• Uses generator to transmit microwave energy
at frequency of 2450MHz via probe placed
within target organ under image guidance
• Application : liver, partial nephrectomy,
prostatic hyperplasia, endometrial bleeding
• Only small area is abalated so it needs
mulitple insertion of probe to treat single
lesion

62. Radiosurgery
• Principle in neurosurgery
• Tool is gamma knife
• Allows more than 200 separate source of high
energy gamma radiation to be focused onto a
minute area in brain
• Ability to destroy minute area in brain and
used in treatment of benign and malignant
neoplasm, AV malformations and epilepsy

63. Cryotherapy
• Destroy cells by freezing and thawing
• With liquid nitrogen or argon circulating
through probe placed over or within lesion
tissue can be frozen to temperature of -35
degree
• Used for cutaneous lesion., tumor of head and
neck, cervix and rectum, prostate
• Major disadvantage: cost

64. Photodynamic therpy
• Administration of target specific photo
sensitizer in target tissue
• Photosensitizing agent is then activated with
wavelength specific light source – leads to
generation of free radicals cytotoxic to target
tissue
• Used in early pancreatic cancer, SCC, BCC,
chest involvement in breast cancer, chest wall
recurrence in breast cancer

65. CUSA
• Cavitron ultrasonic surgical aspirator
• Dissecting device that uses low ultrasonic
frequencies to fragment tissue
• Utilizing hollow titanium tip that vibrates and
cause fragmentation of susceptible tissue,
while concurrently irrigating and aspirating
material from surgical site
• Selectively abalates tissue with high water
content

67. • Advantage:
– Less blood loss
– Improved visibility
– Reduced collateral tissue injury
– Useful in removing non ressectable brain and
spine tumor, non cirrhotic liver and pancreatic
tumor

68. Vessel sealing technology
• Ligasure :
– Combination of pressure and energy-> denaturate collagen
and elastin –> permanent seal
– Seals upto 7mm vessel and withstand 3 times normal SBP
• Enseal :
– Small electrode technology : Uses million of nano
conductive particles each with discrete thermostatic
switch
– Particle interupts current flow when temperature rises and
turns back on when temperature falls
– Vessel wall fuses by compression and protein denaturation

69. REFERENCE
• FISCHER’S MASTER OF SURGERY
• BAILEY AND LOVE
• SABISTON

70. THANK U