Energy modalities used in MIGS

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Energy Modalities
Standard and New Technologies
TEVFİK YOLDEMİR MD. BSc. MA. PhD.
tyoldemir
profdrdryoldemir
• I have no conflict of interest
Different types of available energy sources
and tissue effect produced by them
unmodulated continuous waveform and coagulation refers modu-
lated interrupted waveform. During laparoscopic surgeries
continuous waveform results in flow of low energy electron thus
minimal smoke production with tissue cutting whereas interrupted
waveform is associated with high energy electron flow and more
smoke production with high temperature but better hemostasis.11
Monopolar energy is based on the use of active and passive elec-
trodes. In monopolar electro-surgery, the active electrode is located
on the surgical site. The return electrode is located on the patient, at
site away from surgical site to complete electrical circuit (cautery
plate). The current passes through the patient as it completes the
circuit from the active electrode to the patient return electrode.7,10
It has the ability to use continuous and “mix/blend” current to
dissect tissue while providing some hemostasis, fulguration in the
interrupted mode which results in adequate hemostasis by
carbonizing tissues with high capillary or small vessel density, and
coagulation of grasped tissue can be achieved where desiccation
occurs and proteins denature resulting in a coagulum formation.
Maximum temperature reached after activation is >100 C.11e13
The
tissue effects possible with monopolar electro-surgery include
tissue vaporization and transection, fulguration, desiccation, and
small vessel coaptation.
Bipolar
In bipolar energy sources current passes between two active
electrodes which are in close proximity to each other unlike the
monopolar in which it travels through patient body. As current
passes between tips of instrument, it only affects tissue grasped
between electrodes. These are relatively safe and more useful as
compared to monopolar as it causes minimum collateral spread,
reduce risk of interference with other devices and better coagula-
tion.1
The disadvantage of using conventional electrosurgery are it
cannot cut tissue and requires more time to coagulate causing more
tissue charring and adherence of tissue which may lead tearing of
adjacent vessel causing more bleed.7
These shortcomings were
overcome by advanced new generation bipolar and ultrasonic de-
vices. Conventional electrosurgical devices (monopolar and bipo-
lar) use are associated with stray current injuries like capacitive
coupling, insulation coupling, and direct coupling.13
Ligasure
The Ligasure™ (Valleylab Inc., Boulder, CO, USA) (LS) vessel
sealing instruments use a high-current, low-voltage continuous
bipolar radiofrequency energy in combination with a feedback
controlled response system that automatically delivers and dis-
rupts the power according to the composition and impedance of
the tissue between the jaws of the instruments. It fuses collagen
and elastin within the vessel walls, resulting in a permanent seal
that can withstand three times the normal systolic pressure, and
seals vessels up to 7 mm. Maximum temperature during activation
is below 100 C,14e17
thus reduces thermal spread to 1 mm with LS
Precise and to 1.5 mm with LS V.
Plasma kinetic gyrus
The Plasma Kinetic Gyrus™ (PK) (Gyrus ACMI, Southborough,
MA) is a bipolar electrosurgical device that uses plasma kinetic
technology to deliver a high current at a very low voltage to the
tissue. It has two tier jaw design with serrated surfaces for secure
grasping.
A series of rapid pulses allows a cooling phase during coagulation,
thereby decreasing lateral thermal spread. It can seal vessel up to
7 mm by denaturing the protein within the vessel walls, forming a
coagulum that occludes the lumen. It yields maximum temperature
which is below 100 C.16
This technology does not have a feedback
mechanism like LS and Enseal; however, it allows the physician to
choose how long energy is applied with the aid of audible tone
change, indicating tissue desiccation to the user. This system has
two different modes (vapor pulse coagulation and plasma kinetic
tissue cutting) delivering predetermined levels of energy matched
to special surgical instruments.10
Enseal
ENSEAL™ (Ethicon Endo-surgery, US, LLC) this tissue-sealing
and hemostasis system is a bipolar instrument that combines a
high-compression jaw with a tissue dynamic energy delivery
mechanism. Because of the configuration and the temperature
sensitive matrix (Nanopolar thermostats) embedded within the
jaws of the instrument, each tissue type within the jaws receives a
different energy dose that is constantly changing as the tissue is
being sealed and its impedance changes.10,18
It is the first and only
system that controls energy deposition at the electrode-tissue
interface.19
The instrument has a blade that simultaneously cuts
the sealed tissue. It can seal vessels ranging in diameter from 1 mm
to 7 mm, also sealed vessel walls are capable of withstanding
greater than seven times normal systolic pressure.1
Ultrasonic devices
In 1993, Amaral first described the ultrasonic scalpel for lapa-
roscopy as having the ability to provide both vessel sealing and
tissue transection. However, it gained practical popularity only
from 2010 onwards. It produces tissue effects by converting elec-
trical energy into vibrations at more than 20,000 cycles per second
which is above the audible range.15,20
Instrument consist of trans-
ducer, hand grip, long shaft and blades. The upper blade, called
tissue pad is an inactive one which helps in grasping the tissues and
also prevents the vibrational energy from spreading further while
lower active jaw vibrates and denatures protein in the tissue to
Table 1
Different types of available energy sources and tissue effect produce by them.23,43
Type Tissue effect
Monopolar Vaporization, fulguration, desiccation, coaptation
Conventional bipolar Desiccation, coaptation
Advanced bipolar Ligasure, pk gyrus, ENSEAL Desiccation, coaptation, tissue transection
Ultrasonic technology Ultracision harmonic scalpel, Harmonic ACE,
Harmonic focus, SonoSurg, AutoSonix
Desiccation, coaptation, mechanical tissue transection
Hybrid device Thunderbeat
Laser energy Nd: YAG laser, Argon laser, CO2 laser
Argon beam coagulator System 7550TM ABC, Cardioblate
Radiofrequency (RF) energy RF 3000, starburst, cardioblate
A. Jaiswal, K.-G. Huang / Gynecology and Minimally Invasive Therapy 6 (2017) 147e151148
Gynecology and Minimally Invasive Therapy 6 (2017) 147-151
International Journal of Medical Science and Health Research
Vol. 2, No. 06; 2018
ISSN: 2581-3366
www.ijmshr.com Page 42
vibration and a cutting effect. Meanwhile, coagulation is a less safe waveform because use
modulated low frequency-high voltage current, producing a slow rise in tissue temperature
(between 70 - 85 º C) leading to protein denaturation, desiccation and constriction of the cell
with more thermal spread. In the blend mode, alternation in between the cut and coagulation
waveform is applied, classified in three groups varying in the time spend of activation (50% -
40% - 25%). Other variables under the surgeon control that can modify the tissue effect are the
setting of the electrosurgical unit (ESU), the total time of activation, the size and shape of the tip
and the contact or not of the device tip with the tissue.
Concerns related to the morbidity due to thermal injuries on using monopolar energy contributed
to the develop of bipolar devices in around 1970 by Frangenheim in Germany and by Rioux and
Cloutier in North America. [3,4]
Mechanical energy is based on two major principles: higher speed mobilization and cavitation.
With the use of a piezoelectric part, the electrical energy from the wall outlet is transformed to a
mechanical movement, transmitted to the tip of the instrument. The high speed vibration (over
18.000 Hz) will determine heat and formation-explosion of air cavities within the tissue,
determining destruction of the cells.
Ferromagnetic heat energy is obtained by conducting radio-frequency in a loop coated with
thin micron thick ferromagnetic coating materials, with couples to the high frequency current. As
the radio-frequency passes through this loop, pure thermal heat is generated by magnetic
hysteresis losses and ohmic heating relayed to skin effect, finishing in a sudden and precise rise
and fall of temperature.
Plasma is the fourth state of the matter and is created by adding energy to gas, resulting in a high
energy- low density state. Using ionized inner gas with minimal electricity flow, plasma devices
allows cutting, coagulation and fulguration in the same instrument. Tissue effects of this and
other energies are show in Table 2.
Table 2. Tissue effects of surgical energies
Type of Energy Tissue Effect
Electrical
Monopolar Vaporization - Fulguration - Dessication - Coaptation
Bipolar Dessication - Coaptation
Advanced Bipolar Dessication - Coaptation - Tissue Transection
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ISSN: 2581-3366
Ultrasonic Dessication - Coaptation - Mechanical Tissue
Transection
Plasma Vaporization - Fulguration - Desiccation - Coaptation
Ferromagnetic heat Desiccation - Coaptation - Tissue Transection
Laser Hypertermia - Coagulation – Vaporization
It is paramount to understand the effect of the temperature on tissues. From 41 ºC protein starts
denaturation, and when this injury ( 43 to 60 ºC) is maintain for at least 6 minutes, irreversible
damage is established. Temperature between 60 to 80 ºC leads to “white coagulation” breaking
the protein and hydrogen bonds, unwinding of cellular DNA and collagen denaturation (with
preservation of elastin networks), resulting in about a 30 % shrink in cell length. From 90 ªC and
upper, water starts to evaporate (desiccation) and when 100 ºC is reached, water boil and form a
steam, cell walls rupture due the swelling, resulting in a massive intracellular expansion and a
cellular explosive vaporization with a cloud of steam, ions and organic matter. Over the 200 ºC,
organic molecules are broken down leading to a Black-Brown tissue appearance called the
“black coagulation”. [5] Also, surgeon must remember that the edge for neural damage is 45 º C.
[6]
The purpose of this review is to show and analyze the basic principles, characteristics and safety
issues of the main devices used in laparoscopic surgery. We start giving an introduction on the
energies in surgery. Afterward, we describe the specific characteristics and main devices of each
type of energy. Finally, we discuss the findings and draw conclusions.
Energy Based Surgical Devices
Monopolar devices
Monopolar (MP) electro surgery is the most used modality in laparoscopy. It is associated with
high electron flow, smoke production, higher temperature and hemostasis capacity.[7]
Maximum temperature reached after activation is over 100 ºC.[10,17,18] During surgery,
continuous waveform results in cutting effect, with low flow of electrons and minimal smoke
production, whereas interrupted waveform is used for hemostasis. This is included by defect
depending on the electrosurgical unit (ESU), allowing to select the “cutting” or “coagulating”
setting .Also, using a sharp or blunt electrode tip you can modify the current density, the
temperature and the final tissue effect.[5] Its is accepted that MP devices can safety divide
vessels up to 2mm diameter.[8]
All radio-frequency electro surgery systems are bipolar, but the difference will be done by the
location of the second (return) electrode. In this type, the current passes through the patient as it
Monopolar energy
• Electrosurgical generator has “cut” and “coag” settings, cut refers to
unmodulated continuous waveform and coagulation refers modulated
interrupted waveform.
• continuous waveform results in flow of low energy electron thus
minimal smoke production with tissue cutting
• interrupted waveform is associated with high energy electron flow and
more smoke production with high temperature but better hemostasis
• The tissue effects possible with monopolar electro-surgery include
tissue vaporization and transection, fulguration, desiccation, and small
vessel coaptation. Gynecology and Minimally Invasive Therapy 6 (2017) 147-151
Principles of electrosurgery -1
• Three clinical tissue effects are possible with electrosurgical units:
cutting, fulguration, and desiccation.
• Achieving these effects depends on the following factors:
• current density,
• time,
• electrode size,
• tissue conductivity, and
• type of current waveform.
• The greater the current that passes through an area, the greater
the effect will be on the tissue.
• The greater the amount of heat that is produced by the current,
the greater the thermal damage on tissue.
Current Opinion in Obstetrics and Gynecology 2008, 20:353–358

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• Too long or too short activation will produce either wider and
deeper tissue damage or an absence of the desired tissue
effect.
• The speed with which an electrode is moved will result in
either less or more coagulation and thermal spread.
• Smaller electrodes provide a higher current density and result
in a concentrated heating effect at the site of tissue contact.
• Muscle and skin are good conductors of electricity and have
low resistance, whereas adipose tissue and bone have high
resistance and are poor conductors of electricity
• A cut waveform consists of continuous radiofrequency sine waves
that incorporate higher current but lower voltage than coagulation
waveforms at the same power setting.
• A cutting current power setting must be between 50 and 80 W to
be effective.
• Ideally, the electrode is held slightly away from the tissue to create
a spark gap or steam envelope through which the current arcs to
the tissue.
• This steam envelope results from heating up the atmosphere
between the electrode and the tissue and allows the electrical
energy to cut the tissue cleanly.
• A coagulation waveform is composed of intermittent bursts of
radiofrequency sine waves that have higher voltage and lower current
than a cut waveform of the same power setting.
• Typically, the coagulation current is effective with the power setting in the
range of 30 – 50 W
• Fulguration is noncontact coagulation, which also utilizes the spark gap
concept to mediate the tissue effect that results in heating and necrosis
as well as greater thermal spread.
• Desiccation is nonspark gap coagulation in which direct contact with the
tissue is made during application of the electrosurgical current thereby
resulting in all of the electrical energy being converted into heat within
the tissue. The end result is deeper necrosis and greater thermal spread.
• A blend waveform is a modification of the cutting and the coagulation
waveform and is used when hemostasis is needed while cutting
• If the patient’s return electrode is not large enough to disperse the
current safely, has dried out, or is not completely in contact with the
patient’s skin, then the current exiting the body can have a high
enough density to produce an unintended burn.
• Excessive hair, adipose, scar tissue, and even the presence of
fluid/lotions can diminish the quality of contact between the return
electrode and the patient’s skin.
• It is important that the return electrode be placed on well
vascularized muscle tissue.
5
Monopolar Circuit
This picture represents a common monopolar circuit.
There are four components to the monopolar circuit:
Generator
Active Electrode
Patient
Patient Return Electrode
TISSUE EFFECTS CHANGE AS YOU MODIFY
THE WAVEFORM
Electrosurgical generators are able to produce a variety of
electrical waveforms. As waveforms change, so will the
corresponding tissue effects. Using a constant waveform, like
“cut,” the surgeon is able to vaporize or cut tissue. This waveform
produces heat very rapidly.
Using an intermittent waveform, like “coagulation,” causes the
generator to modify the waveform so that the duty cycle (“on”
time) is reduced.This interrupted waveform will produce less heat.
Instead of tissue vaporization, a coagulum is produced.
A “blended current” is not a mixture of both cutting and
coagulation current but rather a modification of the duty cycle. As
you go from Blend 1 to Blend 3 the duty cycle is progressively
reduced. A lower duty cycle produces less heat. Consequently,
Blend 1 is able to vaporize tissue with minimal hemostasis
whereas Blend 3 is less effective at cutting but has maximum
hemostasis.
The only variable that determines whether one waveform
vaporizes tissue and another produces a coagulum is the rate at
which heat is produced. High heat produced rapidly causes
vaporization. Low heat produced more slowly creates a coagulum.
Any one of the five waveforms can accomplish both tasks by
modifying the variables that impact tissue effect.
Low Voltage High Voltage
Typical Example
100% on
50% on
50% off
40% on
60% off
25% on
75% off
6% on
94% off
6
ELECTROSURGICAL TISSUE EFFECTS
Electrosurgical Cutting
Electrosurgical cutting divides tissue with electric sparks that focus
intense heat at the surgical site. By sparking to tissue, the surgeon
produces maximum current concentration. To create this spark the
surgeon should hold the electrode slightly away from the tissue.
This will produce the greatest amount of heat over a very short
period of time, which results in vaporization of tissue.
Fulguration
Electrosurgical fulguration (sparking with the coagulation
waveform) coagulates and chars the tissue over a wide area.
Since the duty cycle (on time) is only about 6 percent, less heat is
produced. The result is the creation of a coagulum rather than
cellular vaporization. In order to overcome the high impedance of
air, the coagulation waveform has significantly higher voltage than
the cutting current. Use of high voltage coagulation current has
implications during minimally invasive surgery.
Desiccation
Electrosurgical desiccation occurs when the electrode is in direct
contact with the tissue. Desiccation is achieved most efficiently
with the “cutting” current. By touching the tissue with the
electrode, the current concentration is reduced. Less heat is
generated and no cutting action occurs. The cells dry out and form
a coagulum rather than vaporize and explode.
Many surgeons routinely “cut” with the coagulation current.
Likewise, you can coagulate with the cutting current by holding
the electrode in direct contact with tissue. It may be necessary to
adjust power settings and electrode size to achieve the desired
surgical effect. The benefit of coagulating with the cutting current
is that you will be using far less voltage. Likewise, cutting with the
cut current will also accomplish the task with less voltage. This is
an important consideration during minimally invasive procedures.
Cut
Low voltage
waveform
100% duty cycle
Coag
High voltage
waveform
6% duty cycle
CoagBlendPure Cut
Low
Low
Thermal Spread/Charring
Voltage
High
High
USA). Vessel sealer/dividers are available for laparoscopy
along with an instrument line that seals tissue for open or
vaginal surgery. Subsequently, Gyrus ACMI (Maple
Grove, Minnesota, USA), SurgRx, Inc. (Palo Alto, Califor-
nia, USA), and ERBE USA, Inc. (Marietta, Georgia, USA)
are three additional companies that have developed
devices for open, laparoscopic and vaginal applications
[4,6,16–24].
Unique to the Gyrus ACMI platform is the ability to
deliver pulsed energy with continuous feedback control.
This PlasmaKinetic (PK) technology (Gyrus ACMI)
allows the generator to measure tissue impedance during
coagulation and modify delivery of power [25]. This
results in the only technology with a true bipolar cut.
Plasmacision (Gyrus ACMI) is the latest advancement in
PlasmaKinetic technology in which the devices can both
coagulate and cut using adaptive bipolar energy. The
basis of this technology is the passage of current within
the moisture of the tissue during cut and coagulation
cycles. This results in a hemostatic cut with minimal
thermal spread [26
].
The EnSeal Laparoscopic Vessel Fusion System
(SurgRx, Inc.) uses nanotechnologies to autoregulate
the electrosurgical output between the jaws. The device
consists of a truncated I-blade that is centrally set
between nickel embedded plastic jaws that conduct
regulated current and are thermosensitive. Temperature
along the tissue seal is limited to 1008C. It is the first and
only system to control energy deposition at the elec-
trode-tissue interface. Also unique to this particular
7500 psi) with controlled heat delivery, the EnSeal
device confers minimal thermal spread during vessel
sealing [26
,27].
Conclusion
The evolution of electrosurgical devices has been rapid
and continues to improve upon itself to the point that it
has even been incorporated into robotic surgery [28].
Table 1 demonstrates the distinct differences as well
as advantages/disadvantages of the various electrosurgical
devices. The ability of today’s instruments to minimize
blood loss and decrease operative times has had a sig-
nificant impact across all surgical specialties and will
continue to do so as surgeons develop a thorough under-
standing of the proper use of each energy modality. In the
end, more complex pathology can be addressed in a safe
and efficient fashion.
References and recommended reading
Papers of particular interest, published within the annual period of review, have
been highlighted as:
of special interest
of outstanding interest
Additional references related to this topic can also be found in the Current
World Literature section in this issue (p. 424).
1 Wicker P. Electrosurgery – part 1: the history of diathermy. NATNEWS 1990;
27:6–7.
2 Jones CM, Pierre KB, Nicoud IB, et al. Electrosurgery. Curr Surg 2006;
63:458–463.
3 Van Way CW, Hinrichs CS. Technology focus: electrosurgery 201: basic
electrical principles. Curr Surg 2000; 57:261–264.
4 Valleylab. Principles of electrosurgery. Valleylab; 1999. pp. 1–23.
Evolutionary state of electrosurgery Advincula and Wang 357
Table 1 Comparison of energy modalities
Monopolar Traditional bipolar Advanced bipolar
Instrument examples Bovie pencil Kleppinger PlasmaKinetic
Plasmacision
LigaSure
EnSeal
BiClamp
Tissue effect Cutting, coagulation Coagulation Cutting, coagulation
Power setting 50–80 W 30–50 W Default generator setting
Thermal spread Not well assessed
(multiple variables)
2–6 mm 1–4 mm
Maximum temperature 1008C 1008C Not well assessed
Vessel sealing capability Not applicable Not applicable Seals vessels 7 mm
Technique Not applicable Not applicable Tension-free application
Hazards Direct coupling Inadequate for large vessel
coagulation
Insulation failure Increased time needed for
coagulation
Capacitive coupling Tissue adherence

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Monopolar Electrosurgery Tissue Effects
the high fat content of the tissues. Activation of either
continuous or interrupted waveform with tissue con-
tact results in tissue desiccation and protein coagu-
lation; contact with small-medium vessels results in
vessel sealing or coaptation. Although tissue desiccation
is associated with lower tissue temperatures, there is
more pronounced lateral thermal spread than with either
vaporization or fulguration. In general terms, contact
monopolar electrosurgery has a similar tissue effect to
that achieved with bipolar electrosurgery.
Despite the popularity of monopolar electrosurgery
as a laparoscopic energy source, its use is not without
the risk of so-called “stray current injuries.” These in-
clude capacitive coupling, insulation coupling, and direct
coupling (see below).
Bipolar Electrosurgery
Bipolar electrosurgery was developed to decrease the
risk of stray current injury associated with monopolar
electrosurgery, at the same time providing the ability to
seal larger vessels. In bipolar electrosurgery, electric
current passes from one jaw of a grasper (the active elec-
trode equivalent) to the other jaw (the return pad electrode
equivalent). Hence, a return pad electrode attached to the
patient is not required for bipolar electrosurgery (indeed,
the use of a return pad may be associated with unwanted
stray current circuits through the patient). Current con-
ducted through tissue between the instrument jaws will
be desiccated in an analogous fashion to monopolar
electrosurgery used in “closed circuit” (ie, with the active
electrode in direct contact with the tissues). Advantages
of bipolar electrosurgery include a lower voltage re-
quirement to achieve the desired tissue effect (compared
with closed-circuit monopolar electrosurgery), because
the electrodes are in close proximity to each other
(resulting in relatively low tissue impedance). Because
alternating current is used for electrosurgery, the active
and return electrodes rapidly alternate, resulting in a
more even distribution of thermal effect. These factors
should theoretically result in decreased lateral thermal
spread.6
In addition, there is no risk of stray current
injury from capacitive coupling because the bidirec-
tional flow of current in the instrument does not induce
capacitive current.
Disadvantages of bipolar electrosurgery include the
diminished ability to vary operational parameters com-
pared with monopolar electrosurgery: both electrodes
are in contact with the tissues, so electrical current can
only be delivered in “closed circuit”; continuous electri-
cal waveform is standard; and electrodes are relatively
large to enable optimal contact with the tissues. These
factors manifest as a lack of versatility of tissue effects,
as neither tissue vaporization nor fulguration is possible
with bipolar electrosurgery (Table 1). In addition, tissues
can sometimes become adherent to the electrodes, and
disengagement of the instrument tips may cause tissue
trauma or tearing of blood vessels. This phenomenon
usually occurs when there is excessive dehydration of
tissues with resultant tissue charring and may be pre-
vented by activating the energy in a pulsatile manner
and by releasing the tissue just before current flow is
terminated. These thermal effects may be minimized
with advanced bipolar instruments (see below). Another
disadvantage of bipolar electrosurgery is the need to
change instruments to transect the desiccated tissue.
Some modern bipolar devices incorporate a blade for
transecting desiccated tissue without changing instru-
ments, thereby saving time by reducing “instrument
traffic.” Bipolar electrosurgery does not eliminate the
risk of stray current injury from insulation failure (with
or without direct coupling to other instruments) that has
been reported in reusable bipolar instruments.7
Advanced Bipolar Devices
In recent years, a new generation of bipolar devices
has been developed, with some approved by the Food
TABLE 1
Monopolar Electrosurgery Tissue Effects
Tissue Effect Surgical Effect Current Waveform Contact With Tissue Characteristics
Vaporization Cutting Continuous (“cut”) No contact Low-voltage sparks, minimal
smoke, and charring
Fulguration Hemostasis of small
vessels (1 mm)
Interrupted (“coag”) No Contact High-voltage sparks,
smoke, and charring
Desiccation Hemostasis of small
vessels (1 mm)
Continuous (“cut”) or
interrupted (“coag”)
Contact Similar action to bipolar
electrosurgery, pronounced
lateral thermal spread
Coaptation Sealing of small-medium
vessels (2 mm)
Continuous (“cut”) or
interrupted (“coag”)
Contact and compression
of vessel wall
Similar action to bipolar
electrosurgery, pronounced
lateral thermal spread
765Gynecologic Laparoscopic Surgery • CME Review Article
Copyright © 2014 Lippincott Williams Wilkins. Unauthorized reproduction of this article is prohibited.
OBSTETRICAL AND GYNECOLOGICAL SURVEY 2014 Volume 69, Number 12: 763-776
Bipolar energy
• As current passes between tips of instrument, it only affects
tissue grasped between electrodes.
• it causes minimum collateral spread, reduce risk of interference
with other devices and better coagulation
• it cannot cut tissue and requires more time to coagulate
causing more tissue charring and adherence of tissue which
may lead tearing of adjacent vessel causing more bleed
Bipolar - Advanced Bipolar devices
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ISSN: 2581-3366
completes the circuit from the active electrode to the patient return electrode, who is located at a
distance from the surgical site.[9]
According to work published by Jones in 2006, both the cutting and coagulation effect can be
achieved with a power setting (PS) of 50 - 80 Watts (W).[10]
The main risks are the energy escape, direct coupling, capacitive coupling and unintended direct
application. The mean incidence of electrical injuries is 1 to 5 per 1000 cases. [11, 12] Compared
to other devices, this seems to have the higher smoke and vapor production.[13]
Bipolar and advanced bipolar devices (Table 3)
Table 3. Bipolar - Advanced Bipolar devices and main Characteristics
Devices Characteristics
ROBI ®
Everest™ High frequency alternated electrical current
LigaSure - LigaSure V™ (*) 1 to 7 mm of lateral thermal spread
Gyrus PK™(*) Vessel Sealing up to 7 mm
Kleppinger(*)
ERBE Biclamp® (*)
BiCision® (*)
Enseal PTC™(**)
Note: *: Advanced Bipolars. **: Advanced bipolar with Nanotechnology.
Bipolar (BP) born from the pursuit of a safe way of delivering the energy. Using a non
modulated - low voltage current waveform allows the surgeon an effective hemostasis with less
collateral damage and thermal spread (LTS).[14,15] A small circuit of active - passive electrode,
generally represented by the jaws of an instrument, limit the electron flow to a restricted area of
tissue.[16,17]
Broadly talking, traditional bipolar instruments are used for coagulation purposes. Due to the
short separation of the electrodes, lower voltage is required to obtain the effect.[18] With PS
Vol. 2, No. 06; 2018 ISSN: 2581-3366
Ligasure
• vessel sealing instruments use a high-current, low-voltage
continuous bipolar radiofrequency energy in combination with a
feedback controlled response system that automatically delivers
and disrupts the power according to the composition and
impedance of the tissue between the jaws of the instruments
• It fuses collagen and elastin within the vessel walls, resulting in a
permanent seal that can withstand three times the normal systolic
pressure, seals vessels up to 7 mm.
• Maximum temperature during activation is below 100 ℃.
• It reduces thermal spread to 1 mm with LS Precise and to 1.5 mm
with LS V Gynecology and Minimally Invasive Therapy 6 (2017) 147-151
Plasma Kinetic Gyrus
• bipolar electrosurgical device that uses plasma kinetic technology to
deliver a high current at a very low voltage to the tissue.
• It has two tier jaw design with serrated surfaces for secure grasping.
• A series of rapid pulses allows a cooling phase during coagulation,
thereby decreasing lateral thermal spread.
• It can seal vessel up to 7 mm by denaturing the protein within the
vessel walls, forming a coagulum that occludes the lumen.
• It yields maximum temperature which is below 100 ℃
• two different modes (vapor pulse coagulation and plasma kinetic
tissue cutting) delivering predetermined levels of energy matched to
special surgical instruments.Gynecology and Minimally Invasive Therapy 6 (2017) 147-151
Enseal
• a bipolar instrument that combines a high-compression jaw
with a tissue dynamic energy delivery mechanism.
• each tissue type within the jaws receives a different energy
dose that is constantly changing as the tissue is being sealed
and its impedance changes
• It can seal vessels ranging in diameter from 1 mm to 7 mm, also
sealed vessel walls are capable of withstanding greater than
seven times normal systolic pressure

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Ultrasound devices
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ISSN: 2581-3366
Harmonic ACE® - ACE +® -
H1000®
Sonicision™ High speed mobilization and cavitation
SonoSurg™ 1 to 4 mm of Lateral thermal Spread
Autosonix™ Vessel Sealing up to 5 mm
Lotus®
Sonicbeat™
Since the first description of the ultrasonic scalpel by Amaral in 1993, the technology became
widely used, mostly from 2010.[32]
Three generations of US devices have been introduced: The Ultracision Ultrasonic Scalpel®
(First Generation, 1989); the Harmonic ACE®(Second generation: Ultracision™ and
SonoSurg™, 1998 - 2004) and the Sonicision™ (Third generation: 2011). The main difference
between the 2 devices of the second generation is that the SonoSurg™ uses slower US
frequencies (47 kHz vs 55.5 kHz) aiming better hemostatic control.
Sonicision™is the first cordless laparoscopic instrument. In 2012, the Harmonic ACE +®was
launched by Johnson and Johnson (JJ), including a tissue conditions response, similarly to the
last generation devices. Finally in 2017 the Harmonic HD1000i®appeared, the newest US
device launched by Ethicon Endosurgical.
Using a piezoelectric element that converts electrical to mechanical energy by polarity changes,
and provided by two blades (one of these active), a vibration rate between 23.500 to 55.500 HZ
(with 50 - 100 microns amplitude) is generated due to the dilatation - contraction sequence of the
piezoelectric system.[39] The active movement of the titanium blade induces longitudinal / linear
oscillation waves leading to a final mechanical effect on the tissue where applied.[40] Thus,
section and hemostasis is obtain based in two basic principles: The high speed mobilization (over
18 Khz) and the cavitation. The last one, defined as a creation and explosion of cavities in a
liquid state, will generate “cavitional bubbles” at the tip of the instrument due the vibration,
which concentrates in the surface and finally implodes, collapsing and breaking the cell.
Therefore, a cut effect is obtained by increasing of the temperature in the blade surface, protein
denaturation, hydrogen bonds breaking and friction between the blade and tissue due to the
vibrations.No contraction of the vessels sealed and significantly less heat from tissue friction is
obtain.[41,42] This is quite different to bipolar energy, which reduces the vessel caliber and
creates a proximal thrombus within it.
Vol. 2, No. 06; 2018 ISSN: 2581-3366
Ultrasonic devices
• It produces tissue effects by converting electrical energy into
vibrations at more than 20,000 cycles per second which is above
the audible range
• Instrument consist of transducer, hand grip, long shaft and
blades. The upper blade, called tissue pad is an inactive one
which helps in grasping the tissues and also prevents the
vibrational energy from spreading further while lower active jaw
vibrates and denatures protein in the tissue to form a sticky
coagulum.
• Harmonic ACETM seals vessel up to 5 mm in diameter.
Ultrasonic devices
• It has five power levels. Increasing the power level increases
cutting speed and decreases coagulation.
• Less power decreases cutting speed and increases coagulation.
However, the study had stated the ultrasonic devices reaching
temperatures of up to 200 ℃ which can cause lateral thermal
damage to adjacent tissue.
• A new Harmonic ACE+7 can seal vessels up to 7-mm diameter.
Hybrid device
Vol. 2, No. 06; 2018
ISSN: 2581-3366
Ultrasound and electrical current
Thunderbeat ™ Less than 5 mm of lateral thermal spread
Seal vessels up to 7 mm
Fastest surgery and higher versatility among all
It allows delivery of electrical bipolar and ultrasonic frictional heat energy, giving it a wide
versatility based in five variables: hemostasis, cutting, desiccation, histologic sealing and tissue
manipulation. All those determine a faster surgery and higher versatile score when compares
with any other device, with higher bursting pressure and lower LTS.[43] The generator has three
levels starting from 1 (cut and seal mode) to 3 (seal mode).[32]
Milsom in 2012 comparing TB, ACE®, LS and ES found the TB has the shorter dissection time
and the higher versatility score among all, with no significant differences in LTS and burst
pressure.[43,53]
In laboratory, can seal vessels up to 7 mm diameter.[51,53] Among all devices gives better field
visibility and faster average cutting time(10.7 sec).[43]
Devices Comparation in Gynecological Surgery
The main studies comparing operative time, blood loss, post operative pain score, complications
and hospital stay of these newer instruments in humans, was analyzed and presented by Amruta
Jaiswal and his group on the Gynecology and Minimally Invasive Therapy in 2017.[32]Main
findings of four randomized controlled, one cohort and three retrospective studies reveal:
1. All these new energy devices decrease surgical time and increase versatility during
surgery compared to conventional electro coagulation.
2. Insufficient evidence to consider a specific device/vessel sealing technology superior to
the other.
3. Thunder beat™ appears to be associated with short operative time and less post
operative pain.
4. Gyrus PK™ appears to have less blood loss when compares to conventional electro
surgery.
5. LS appear to have less operative time and blood loss when compares to HS.
CONCLUSION
Vol. 2, No. 06; 2018 ISSN: 2581-3366
Thunderbeat
• the first device to integrate both ultrasonically generated frictional
heat energy and advanced bipolar energy in one instrument.
• The ultrasonic technology rapidly cuts and precisely dissects tissue
while the advanced bipolar technology provides reliable vessel sealing.
• It can seal and cut vessels up to 7 mm in size with minimal thermal
spread.
• The generator has level 1 for cutting and sealing while level 3 for
sealing mode.
• The jaw is designed to provide precise, controlled dissection and
continuous bipolar support with grasping capability
Comparison between main devices used in
laparoscopic surgery
Vol. 2, No. 06; 2018
ISSN: 2581-3366
absorbing - dissipation of the heath. Lower values are associated with faster heating and tip
cooling, but more heat dissipation, and therefore the risk of damaging surrounding tissues. [50]
An evaluation of three US devices (ACE®, Sonicision™ and SonoSurg™) was presented by
Kim in 2014. Applying cutting and coagulating setting to a bovine mesentery and lamb renal
veins, found no significant differences in emissitivity and maximum coagulation temperatures
among them, ranging from 0.39 - 0.49 and 187 - 193 ºC respectively. Soncision™ show the
maximum cutting temperature (227.1ºC) followed by the ACE® (191.1ªC) and SonoSurg™
(184.4ºC). The cooling time (to reach 60º C after de-activation) was significantly lower for the
SonoSurg™(27.4 sec.) compared to ACE®(35.7sec.) and Sonicision™ ( 38.7 sec).[50] Similar
results were found by Seehofer in 2012, comparing Thunder beat™ (TB), ACE® and LS in a
pig model found that that TB and ACE®reach temperatures significantly higher than LS ( 192 -
209 ªC), with longer cooling time after de-activation.[51] A summary of these and other results
are shown in Table 6.
Table 6. Comparison between main devices used in laparoscopic surgery ( Combined data
from Lamberton et al., Kim et al; Hefermehl et al; Alkatout et al., Newcomb et al., Milsom et
al,, Seehofer et al.and Obona et al.)
Devices LTS.
.
MAXIUM
TEMPERA
TURE
SMOKE
PRODUC
TION
MEAN
BURST
PRESSUR
E
TIME TO
SEAL. .
TISSUE
STICKING
Harmonic
Scalpel™
49(1.5m
m)
200 Low 454 14 Low
LigaSure™ 55(1.7m
m)
Below 100 Low 615 10 Middle
EnSeal™ 58(1.8m
m)
100 Medium 678 19 Low
Thunderbeat™No Data (1.6 mm ) 200 Low 734 10.7. Lowest
* Note: LTS: Lateral thermal spread (Celsius grade at 2 millimeters lateral - lateral histologic
damage); MEAN BURST PRESSURE: MmHg; TIME TO SEAL: Seconds; TISSUE
STICKING: Low: No or minor sticking, Middle: Requiring activation of instrument to release
tissue.
Other devices
Vol. 2, No. 06; 2018 ISSN: 2581-3366

9.02.2019
5
efficiency and efficacy of different electrosurgical devices
• Efficiency of any energy source depends on seal time, lateral thermal
spread, burst pressure, smoke production.
• There are animal studies comparing Ligasure V, Gyrus PK, an
ultrasonic device, and ENSEAL.
• A trend toward lower burst pressures and higher failure rates as
vessel diameter increased for all 5 mm laparoscopic instruments
tested was shown.
• Overall highest burst pressures and lowest failure rates were seen
with the EnSealTM (RX), LigaSure VTM with LigaSureTM Vessel Sealing
generator (LS), and LigaSure VTM with Force TriadTM generator (FT) .
• The seal time was significantly faster for LigaSure VTM with Force
TriadTM generator (FT) compared to LigaSure VTM with LigaSureTM
Vessel Sealing generator (LS) for all vessel sizes (P 0.05) and faster
than EnSealTM (RX) for both 4-5 mm and 6-7 mm vessels (P 0.05),
making seal time a differentiating factor between devices with the
highest burst pressures and lowest failure rates.
• Versatility score (depending on hemostasis, histologic sealing, cutting,
dissection, and tissue manipulation) was higher (P 0.01) and
dissection time was shorter (P 0.01) using Thunderbeat (TB)
compared with Harmonic ScalpelTM (HS), Enseal and LigaSure VTM with
LigaSureTM Vessel Sealing generator (LS)
• A study comparing LigaSure VTM with LigaSureTM Vessel Sealing
generator (LS) vs. Plasma kinetic gyrus (PK) vs. Harmonic ace vs. Enseal
in simulator with bovine arteries of 5 mm size
• Burst pressure as LS ES HS,
• Smoke production as HS LS PK,
• Sealing time shorter for LS (10 s) PK (11.1 s) HS (14.3 s) Enseal (19.2 s).
• Lateral thermal spread less with HS (49.9 ℃ ) PK (64.5 ℃) but same for LS
(55.5 ℃) and Enseal (58.9 ℃).
• LS has the highest burst pressure and fastest sealing time and was the highest
rated overall
• The HS produced the lowest thermal spread and smoke but had the lowest
mean burst pressure. Gynecology and Minimally Invasive Therapy 6 (2017) 147-151
• The GP had the highest smoke production, and variable burst pressures.
• The burst pressure of the TB in the larger-artery category (5-7 mm) was
superior to that of the HA.
• The highest mean burst pressure was measured in the TB group (734 ±
64 mmHg); this was slightly higher than in the LS (615 ± 40 mmHg) group
and significantly higher than in the HA group (454 ± 50 mmHg).
• The dissection speed of the TB was significantly faster than that of the LS
and slightly faster than HA.
• The temperature profile of the HA and the TB was similar with respect to
the maximum heat production and the kinetics of cooling down to 60 ℃.
• The maximum temperature during activation and shortly thereafter was
around 200 ℃ in the HA and TB groups.
• In contrast, the temperature in the LS group during and after activation
was constantly below 100 ℃ Gynecology and Minimally Invasive Therapy 6 (2017) 147-151
• All laparoscopic energy sources, to a lesser or greater extent cause lateral
thermal spread, irrespective of vaporization, fulguration, desiccation, or
coaptation effect; a temperature beyond the ‘‘cell kill’’ threshold may occur
causing inadvertent tissue damage increasing morbidity and mortality.
• Smoke or vapor plumes hampering visibility is mostly observed with monopolar,
whereas least seen with ultrasonic devices.
• Second most common complication associated with laparoscopy surgery after
veress or trocar placement (41.8%) are related to electrosurgical devices (25.6%).
• Possible mechanisms behind injuries are
• mistaken target application,
• stay current injury due to defective insulation,
• direct coupling (when active electrode touches another metal instrument), c
• apacitive coupling,
• alternative site burns (due to defective dispersive pad).
Table 2
Comparative studies of different electrosurgical device.
Author Type of study Device Sample size (N) Procedure Operative time
(Min.) (Mean)
Blood loss (mL) Postoperative
pain score
Complication Hospital stay
(days)
Inference
Anna fagoti 2014 et al.28
Randomized,
controlled trial
TB vs. standard
electrosurgery
(SES)
N ¼ 71 (excluded 21
due to intraoperative
criteria).
TB ¼ 25
SES ¼ 25
Laparoscopic
radical
hysterectomy with
bilateral pelvic
lymphadenectomy
TB-85
SES-115
(P ¼ 0.001)
TB-50
SES-50
(P ¼ 0.52)
At 24 h
TB-1.96
SES-3.35
(P ¼ 0.005)
TB-0
SES-1
(P ¼ 0.31)
TB-3
SES-3
(P ¼ 0.82)
TB associated with
short operative
time and less
postoperative pain
Hakan ayatan et al 2014.33
Randomized
prospective
study
LS vs. Enseal vs. PK N ¼ 45
LS ¼ 15
PK ¼ 15
Enseal ¼ 15
Total laparoscopic
hysterectomy
LS-52.4
Enseal-55.7
PK-51.9
(P ¼ 0.73)
LS-138
Enseal-218
PK-118
(P ¼ 0.004)
e e LS-1.1
Enseal-1.4
PK-1.2
(P ¼ 0.22)
No significant
difference except
more blood loss in
Enseal group
Ralf Rothmund et al 201329
Prospective,
randomized,
controlled trial
Enseal vs. standard
bipolar
N ¼ 160, Enseal-80
bipolar e 80
Laparoscopic
Supracervical
hysterectomy
Enseal-78.18
Bipolar e 86.3
(P ¼ 0.03)
Enseal-50
mL (n ¼ 72)
50e100 mL
(n ¼ 8)
Bipolar e 50 mL
(n ¼ 62)
50e100 mL (18)
(P 0.001)
No significant
difference
No significant
difference
Enseal-2.01
Bipolar e 2.17
(P ¼ 0.03)
EnSeal device is at
least as reliable as
the conventional
electrocoagulation
technique in
laparoscopic
supracervical
hysterectomy
(LASH).
Total resection time
was shorter in the
experimental
group, and the
other investigated
clinical parameters
were not inferior in
the experimental
group compared
with the control
group
Janssen et al. 201131
Randomized
controlled trial
LS vs. CB N ¼ 140
LS-70
CB-70
Laparoscopic
hysterectomy
LS-148.1
CB-142.1
(P ¼ 0.46)
LS-234.1 mL
CB-273.1
(P ¼ 0.46)
e e LS-2.9
CB-2.9
(P ¼ 0.94)
No significant
differences in
operating time and
blood loss
Hsuan su et al.201130
Retrospective
study
PK vs. CES N-194
PK ¼ 97
CES ¼ 97
Laparoscopic
myomectomy
PK-117.8
CES-116.6
(P ¼ 0.906)
PK-190.4
CES-234.8
(P ¼ 0.025)
e e PK-2.7
CES-2.8
(P ¼ 0.315)
PK has advantage of
less blood loss
Demirturk et al (2007)34
Retrospective
study
HS vs. LS N ¼ 40
HS-19
LS-21
Total laparoscopic
hysterectomy with
salpingo-
oophorectomy
HS-90.95
LS-59.57
(P 0.001)
HS-152.63
LS-87.76
(P 0.001)
e e HS-3.42
LS-3.24
(P ¼ 0.436)
LS has advantage of
less operative time
and less blood loss
compared to HS
Lee et al. 200732
Retrospective
caseecontrol
study
PK vs. CB N ¼ 76
PK-38
CB-38
Laparoscopic
radical
hysterectomy with
pelvic
lymphadenectomy
PK-172
CB-229
(P 0.001)
PK-397 mL
CB-564 mL
(P 0.03)
e Less for PK
(P 0.01)
PK e 6.9
CB-7.5
(P ¼ 0.1)
PK has advantage of
less blood loss,
shorter operative
time and less post-
operative
complications
Wang et al. 200535
Prospective,
non
randomized
trial
PK vs. CB N ¼ 62
PK-31
CB-31
LAVH PK-87.6
CB-93.4
(P ¼ 0.368)
PK-196.8
CB-253.2
(P ¼ 0.105)
e e PK-3.2
CB-3.0
(P ¼ 0.499)
Operation time,
blood loss,
transfusion rate,
length of hospital
stay: no significant
difference
Conventional bipolar- CB, Conventional Electrosurgery-CES, Harmonic scalpel- HS, Ligasure- LS, Plasma kinetic gyrus-PK, standard electrosurgery- SES, Thunderbeat-TB.
A.Jaiswal,K.-G.Huang/GynecologyandMinimallyInvasiveTherapy6(2017)147e151150
Thunderbeat, Ligasure, Gyrus PK, Harmonic and Enseal are better
than or as reliable as conventional electrocoagulation.

9.02.2019
6
the application of electrosurgical devices between
experienced surgeons and surgical residents
Meeuwsen et al 375
Patient Characteristics
Relevant patient information and perioperative details
about the procedure were obtained from the hospital
information system (CS-EZIS, ChipSoft, Amsterdam,
The Netherlands). Surgery was performed on 30 men and
61 women, with an average age of 54 years (range 18-86
years). With an average body mass index (BMI) of 29
(range 18-44) our patients were generally overweight.
Forty-five patients had abdominal surgery before, which
may lead to adhesions and could make surgery more dif-
ficult. Four patients were admitted with an acute diagno-
sis; all others patients were scheduled on an elective
basis. Spillage of gallstones and bile during the procedure
was even for surgeons and residents, respectively, 14 and
10 times. Blood loss was not reported in 28 of proce-
dures, so is excluded in this analysis. No conversions to
laparotomy have occurred.
Data Analysis
The used sensor, measuring the electric current supplied
to the electrosurgical device, enables accurate detection
of device activation and a reliable estimate of the power-
level settings. A threshold of 15 mA was selected in the
data sets to detect single activations of the electrosurgical
device. An activation started when the signal reaches a
value higher than 15 mA and ended when the signal
dropped below it. The start and end times of procedures
were obtained from the hospital information system, and
the current sensor data were selected manually according
these timestamps.
Combining all available information, we were able to
detect the following parameters:
•• First moment of activation during the process
•• Last moment of activation during the process
•• Number/amount of activations
•• Duration of separate activations
•• Estimated height of activation
•• Duration of total device usage
Statistics
To control for possible effects of patient characteristics
on the use of the electrosurgical device we first deter-
mined whether the sex, age, BMI, and previous abdomi-
nalsurgerywascorrelatedwithanyoftheabove-mentioned
parameters. Pearson product-moment correlation coeffi-
cients were obtained to see whether there was a relation
between the number and duration of activations and the
duration of use of the device. Student’s t tests were per-
formed to determine whether there were significant dif-
ferences between the means of the grouped data of experts
and of the residents. Analysis was done with use of
MATLAB (version R2014b, MathWorks, Natick, MA).
Results
Activation Patterns
Laparoscopic cholecystectomies have a relatively stan-
dard execution. However, in this study the total procedure
time varied extensively (range 9 minutes to 1 hour 44 min-
utes, average 44 minutes). As an illustration, Figure 2A
shows that the use of the electrosurgical device was initi-
ated about 19 minutes after the first incision, indicating
that this was the time needed for placing the trocars and
reaching the gallbladder. Next, the electrosurgery device
was activated between the 19th minute and the 22nd min-
ute. At around the 25th minute a second burst of activa-
tions is seen. In contrast, in Figure 2B a more frequent
use of the device is seen.
With respect to the activation patterns of the electrosur-
gery device, several patterns were observed. Figure 2A
shows the pattern of an expert surgeon, whereas Figure
2B shows the performance of a surgical resident.
Activation Parameters
Analysis showed that there were no correlations between
the different patient characteristics, such as BMI, sex,
Figure 2. The activation patterns of the electrosurgical
device of a surgeon (A) and a resident (B). On the horizontal
axis the time in minutes is shown, starting immediately at
the time of first incision and ending with the actual end-time
of the procedure. On the y-axis the measurement data are
provided.
Surgical Innovation 2017, Vol. 24(4) 373–378
Meeuwsen et al 377
Possibly the apparent lack of knowledge about the
theoretical background is a factor in the development of
different application methods among surgeons and resi-
dents. An initiative from SAGES (Society of American
Gastrointestinal and Endoscopic Surgeons) called the
Fundamental Use of Surgical Energy (FUSE) program is
introduced to improve knowledge among surgeons and
residents about this subject.6,14
Also other studies about
knowledge-based programs show positive results.20
However, none of the currently offered teaching pro-
grams deal with all practical aspects of safe application of
electrosurgery.
In the current study, we took the first steps in obtaining
data on the application of electrosurgery from a large
number of procedures to eventually define the objectives
for an outcome-based training program. Outcome-based
education is an educational method that centers each part
of an educational system on goals (outcomes). An exam-
ple is the constructive alignment theory by Biggs.21
According to this theory, the objectives, learning activi-
ties, and assessments should be in line for effective teach-
ing and learning. For example, if students need to learn
how to present, they should be given the opportunity to
practice giving presentations, not only reading a book
about it. If this theory is applied to the training in electro-
surgery, residents in surgery should not only have theo-
retical education but also be offered practical skills
training and assessments. In this respect, without clear
knowledge of the objectives, an effective training pro-
gram cannot be developed according to Biggs theory. Our
approach makes it possible to gain detailed insight into
the use of electrosurgery devices by surgeons of different
levels of expertise.
With the availability of objective measurement tech-
niques, we can take the next step in developing a more
solid training program for surgical residents. We propose
including a hands-on component in the training curricu-
lum for electrosurgery. This could include a session in
which the application technique of the resident is moni-
tored in real-time and in which the effects of application
of different settings are made explicit. This could be
embedded in basic laparoscopic courses.
We conclude that differences are seen in the applica-
tion of electrosurgical devices between experienced sur-
geons and surgical residents in terms of the number of
activations and the activation times during a procedure.
Detailed application measurements can offer the opportu-
nity to relate technical approaches to clinical outcome
and to provide input for the development of a best prac-
tice model.
Authors’ Note
This study was presented at EAES 2016, June 18, 2016,
Amsterdam, The Netherlands.
Acknowledgments
The authors would like to thank Arjan van Dijke for technical
support, and the operating room staff of the Reinier de Graaf
Hospital, Delft, The Netherlands, for their collaboration during
the measurements.
Figure 4. Boxplots of the number of activations and the mean activation time per procedure.
Device cooling time for each device to cool
down from a maximum temperature
Surg Laparosc Endosc Percutan Tech 2015;25:e37–e41
7 types of energy devices:
AutoSonix (AU),
SonoSurg (SS),
Harmonic Scalpel (HS),
LigaSure Atlas (LA),
LigaSure Dolphin Tip (LD),
monopolar diathermy (Mono),
and bipolar scissors (Bi).
conditions among devices, including an ultrasonic coagu-
lation device and LigaSure, and reported the greatest
damage with monopolar diathermy, which was similar to
our experimental findings.
In contrast, the LA and LD use a bipolar feedback-
controlled sealing system,8 and like the Bi, are energy
devices based on the principle of bipolar coagulation. With
these 3 devices, the temperature rise of the dissected adja-
cent tissue did not exceed 201C. Because current is applied
between 2 nearby points to coagulate tissue, a smaller
amount of electrical energy passes through the surrounding
tissue. With ultrasonic coagulation and cutting devices, the
blade uses high-frequency vibration to coagulate proteins,6
so no electrical energy passes through the tissue. The kinetic
energy generated by vibration is converted into heat (ther-
mal energy) which is transmitted to the surrounding tissue.
With these 3 devices, the temperature rise did not exceed
131C in full mode, and did not exceed 241C even in variable
mode. Between variable mode and full mode, no large
differences in temperature rise were seen in any of these 3
devices themselves. However, the higher temperature rise of
the adjacent tissue in variable mode as compared with full
mode was due to the longer required dissection time for the
variable mode, which results in longer contact time of
the tissue with the high-temperature blade. Our findings
ultrasonic coagulation and cutting devices that generate
heat from kinetic energy, all reached temperatures exceed-
ing 1001C. These temperature rises were higher than those
with the Mono, LA, LD, or Bi, which use electrical energy
for coagulation. In a study under atmospheric conditions,
Kim et al15 similarly reported that peak temperature with
the HS reached Z1001C.
We observed a correlation between device maximum
temperature and time required for the device to cool down
to 501C. This suggests that the factor determining the time
until device temperature decline is the maximum temper-
ature rise of the device rather than the device type or
material. For the 3 ultrasonic coagulation and cutting
devices (AU, SS, and HS), irrespective of mode, temper-
atures remained Z1001C even at 8 seconds after dissection
was completed. It is difficult to assure how much temper-
ature of instrument would be safe to dissect human tissue.
At least temperature of instrument should not be Z601C,
because proteins will begin to denature at 601C18 (Fig. 5).
If an ultrasonic coagulation and cutting device is
subsequently applied for another tissue dissection after an
initial procedure, a thermal injury of the tissue may occur
due to already increased high temperature of the previously
used device. Ultrasonic coagulation and cutting devices
should thus be reapplied only after adequate cooling.
However, even at 8 seconds after use, device temperatures
were still Z1001C. Even with the HS in full mode, the
device setting with the fastest time to cool down, approx-
imately 40 seconds is required to cool down to 601C
before further use. Taking this into account, rather than
saving on forceps exchange time and continuing to use the
ultrasonic coagulation and cutting device, switching to
appropriate forceps and proceeding to the next maneuver is
safer and actually saves time.
CONCLUSIONS
Monopolar diathermy caused the highest rise in
adjacent tissue temperature. AU had the highest temper-
ature rise in the device itself, but the other ultrasonic
coagulation and cutting devices also reached temperatures
exceeding 1001C. Our findings suggest that when using
monopolar diathermy for coagulation and dissection, the
risk of thermal injury to adjacent tissue must be considered,
and a sufficient distance from organs must be maintained.
In addition, because ultrasonic coagulation and cutting
devices reach high temperatures, adequate cooling of these
devices is necessary before use in a subsequent maneuver.
REFERENCES
1. Sietses C, Eijsbouts QAJ, von Blomberg BM, et al. Ultrasonic
energy vs. monopolar electrosurgery in laparoscopic cholecys-
tectomy: influence on the postoperative systemic immune
response. Surg Endosc. 2001;15:69–71.
2. Abe K, Terashima M, Fujiwara H, et al. Experimental
evaluation of bursting pressure in lymphatic vessels with
ultrasonically activated shears. World J Surg. 2005;29:106–109.
3. Clements RH, Palepu R. In vivo comparison of the coagu-
lation capability of SonoSurg and Harmonic Ace on 4 mm and
5 mm arteries. Surg Endosc. 2007;21:2203–2206.
FIGURE 4. Relationship between cooling time needed from a
maximum temperature to reach 501C and a maximum temper-
ature of the devices.
FIGURE 5. Device cooling time for each device to cool down
from a maximum temperature, indicating that all ultrasonic
coagulation and cutting devices still keep over 1001C even at
8 seconds after deactivation.
e40 | www.surgical-laparoscopy.com Copyright r 2014 Wolters Kluwer Health, Inc. All rights reserved.
how long must the surgeon wait to touch
additional tissue?
Methods
Regulatory exemption due to designation of this study as
nonhuman research was obtained from the Colorado Multi-
Institutional Review Board (COMIRB #08-1377). The
laparoscopic instruments studied were the monopolar
L-hook (Conmed System 5000; Conmed, Centennial, CO),
30-W fulguration; the argon beam (Conmed), 75-W/7-l/
min flow; bipolar tissue fusion (Ligasure 5 mm; Covidien,
Boulder, CO, USA) set at two bars; and ultrasonic dis-
section (Harmonic ACE; Ethicon, Cincinnati, OH, USA) at
a power setting of 5.
Thermography was performed using a Flir camera
(Boston, MA, USA) in the 3- to 5-lm infrared range using
Thermacam Researcher Professional 2.8 software (Boston,
MA). The instrument tips were painted a flat black
(emissivity, 0.95). Bovine liver was used (emissivity, 0.94).
Emissivity, the ability of an object’s surface to emit energy
by radiation, is important for calibration of the infrared
camera.
To simulate realistic operative usage, each instrument
was activated 5 s four consecutive times, with 5 s pauses
between fires (Fig. 1). To simulate realistic operative
usage, the instruments were fired on a separate piece of
bovine liver tissue for each of the four activations. For the
argon and monopolar procedures, the energy was arced
over onto the tissue (fulguration), and there was not direct
contact between the active electrode and the tissue (des-
iccation). For the ultrasonic and bipolar tissue fusion pro-
cedures, tissue was grasped in the jaws of the instrument
during each activation. The peak temperatures of each
instrument were recorded by placing the tip of the instru-
ment in front of the infrared camera immediately after the
fourth (and final) activation.
The change in temperature of the bovine liver tissue was
measured 2.5, 5, 10, and 20 s after the fourth (and final)
activation. After the fourth activation, the instrument was
held in the air for 2.5, 5, 10, and 20 s before liver tissue
was touched. The temperature of the liver was measured
immediately after the instrument touched the tissue for 2 s.
This peak temperature was subtracted from the baseline
liver temperature to produce the reported data of a change
in temperature from baseline. The baseline temperature of
the liver tissue was recorded before each run.
Each measurement was repeated five times. The results
were reported as mean ± standard deviation. Statistical
analysis was performed using analysis of variance
(ANOVA) with multiple comparisons. Significance was set
at a P value 0.05.
Results
The maximum instrument tip temperature of the four lap-
aroscopic energy sources was measured immediately after
the fourth (and final) activation (Table 1). Ultrasonic
energy had the highest peak tip temperature, followed by
the monopolar, bipolar, and argon beam energy.
The temperature increase in bovine liver tissue from
baseline was recorded at several time intervals (2.5, 5, 10,
and 20 s) after the fourth (and final) activation. The
instrument tip then was touched to the tissue for 2 s
Fig. 1 Experimental energy activation sequence. To simulate real-
life operative energy usage, all energy devices were activated four
times (labeled as numbers 1–4) for 5 s each. Between activations, 5-s
pauses (during which time no energy was delivered to the instrument)
were used (labeled on the diagram as ‘‘off’’). Thermal measurements
began after the fourth (and final) activation
Table 1 Maximum instrument tip temperature
Instrument tip temperature (8C)
Argon beam 0.8 ± 1.0
Monopolar 81.5 ± 18.1
Bipolar tissue fusion 45.8 ± 18.6
Ultrasonic 172.6 ± 62.9
Analysis of variance multiple comparisons of instrument tip tem-
perature: argon versus monopolar (P = 0.10), argon versus bipolar
(P = 0.315), argon versus ultrasonic (P 0.001), monopolar versus
bipolar (P = 0.701), monopolar versus ultrasonic (P = 0.004), and
bipolar versus ultrasonic (P 0.001)
Table 2 Maximum residual heat induced rise in tissue temperature
during an interval of rest after final activation
Increase in tissue temperature measured (°C)
Argon
beam
Monopolar Bipolar
tissue
fusion
Ultrasonic P value
(US vs. all
others)
2.5 s 14.0 ± 1.4 21.1 ± 3.7 28.6 ± 2.7 53.6 ± 11.9 0.001
5 s 14.3 ± 1.2 17.2 ± 2.9 19.7 ± 8.2 58.0 ± 10.8 0.001
10 s 31.2 ± 1.6 13.6 ± 1.2 18.8 ± 3.6 37.9 ± 9.0 0.001
20 s 11.6 ± 1.8 7.8 ± 3.3 14.5 ± 5.2 23.8 ± 7.9 0.050
US ultrasonic energy
The ultrasonic device increased tissue temperatures more than the
other three energy devices during all four periods. At 20 s, compar-
ison of ultrasonic energy with the other devices showed argon beam
(P = 0.010), monopolar (P = 0.001), and bipolar tissue fusion
(P = 0.045)
3500 Surg Endosc (2011) 25:3499–3502
123
Surg Endosc (2011) 25:3499–3502
mption due to designation of this study as
arch was obtained from the Colorado Multi-
eview Board (COMIRB #08-1377). The
nstruments studied were the monopolar
ed System 5000; Conmed, Centennial, CO),
on; the argon beam (Conmed), 75-W/7-l/
lar tissue fusion (Ligasure 5 mm; Covidien,
USA) set at two bars; and ultrasonic dis-
nic ACE; Ethicon, Cincinnati, OH, USA) at
g of 5.
hy was performed using a Flir camera
USA) in the 3- to 5-lm infrared range using
searcher Professional 2.8 software (Boston,
strument tips were painted a flat black
5). Bovine liver was used (emissivity, 0.94).
ability of an object’s surface to emit energy
s important for calibration of the infrared
realistic operative usage, each instrument
5 s four consecutive times, with 5 s pauses
(Fig. 1). To simulate realistic operative
ruments were fired on a separate piece of
sue for each of the four activations. For the
nopolar procedures, the energy was arced
issue (fulguration), and there was not direct
contact between the active electrode and the tissue (des-
iccation). For the ultrasonic and bipolar tissue fusion pro-
cedures, tissue was grasped in the jaws of the instrument
during each activation. The peak temperatures of each
instrument were recorded by placing the tip of the instru-
ment in front of the infrared camera immediately after the
fourth (and final) activation.
The change in temperature of the bovine liver tissue was
measured 2.5, 5, 10, and 20 s after the fourth (and final)
activation. After the fourth activation, the instrument was
held in the air for 2.5, 5, 10, and 20 s before liver tissue
was touched. The temperature of the liver was measured
immediately after the instrument touched the tissue for 2 s.
This peak temperature was subtracted from the baseline
liver temperature to produce the reported data of a change
in temperature from baseline. The baseline temperature of
the liver tissue was recorded before each run.
Each measurement was repeated five times. The results
were reported as mean ± standard deviation. Statistical
analysis was performed using analysis of variance
(ANOVA) with multiple comparisons. Significance was set
at a P value 0.05.
Results
The maximum instrument tip temperature of the four lap-
aroscopic energy sources was measured immediately after
the fourth (and final) activation (Table 1). Ultrasonic
energy had the highest peak tip temperature, followed by
the monopolar, bipolar, and argon beam energy.
The temperature increase in bovine liver tissue from
baseline was recorded at several time intervals (2.5, 5, 10,
and 20 s) after the fourth (and final) activation. The
instrument tip then was touched to the tissue for 2 s
ntal energy activation sequence. To simulate real-
rgy usage, all energy devices were activated four
numbers 1–4) for 5 s each. Between activations, 5-s
ich time no energy was delivered to the instrument)
d on the diagram as ‘‘off’’). Thermal measurements
urth (and final) activation
m instrument tip temperature
Instrument tip temperature (8C)
0.8 ± 1.0
81.5 ± 18.1
ion 45.8 ± 18.6
172.6 ± 62.9
nce multiple comparisons of instrument tip tem-
ersus monopolar (P = 0.10), argon versus bipolar
n versus ultrasonic (P 0.001), monopolar versus
01), monopolar versus ultrasonic (P = 0.004), and
rasonic (P 0.001)
Table 2 Maximum residual heat induced rise in tissue temperature
during an interval of rest after final activation
Increase in tissue temperature measured (°C)
Argon
beam
Monopolar Bipolar
tissue
fusion
Ultrasonic P value
(US vs. all
others)
2.5 s 14.0 ± 1.4 21.1 ± 3.7 28.6 ± 2.7 53.6 ± 11.9 0.001
5 s 14.3 ± 1.2 17.2 ± 2.9 19.7 ± 8.2 58.0 ± 10.8 0.001
10 s 31.2 ± 1.6 13.6 ± 1.2 18.8 ± 3.6 37.9 ± 9.0 0.001
20 s 11.6 ± 1.8 7.8 ± 3.3 14.5 ± 5.2 23.8 ± 7.9 0.050
US ultrasonic energy
The ultrasonic device increased tissue temperatures more than the
other three energy devices during all four periods. At 20 s, compar-
ison of ultrasonic energy with the other devices showed argon beam
(P = 0.010), monopolar (P = 0.001), and bipolar tissue fusion
(P = 0.045)
Surg Endosc (2011) 25:3499–3502
(Table 2; Fig. 2). Ultrasonic energy increased the tissue
temperature the most (maximum increase, 58°C at 5 s) and
for the longest time (tissue remained 24°C above baseline
20 s after the final activation). The ultrasonic energy tips
continued to increase the tissue temperature even after the
final activation was completed (the 54°C change at 2.5 s
increased to a 58°C change at 5 s), a phenomenon that did
not occur with the other three energy sources.
Discussion
The residual heat of laparoscopic electrosurgical instru-
ments is relevant. The current study found that three energy
sources (monopolar, bipolar tissue fusion, and ultrasonic
devices) raised tissue temperature by a clinically relevant
20°C if the wait after the final activation until additional
tissue is touched is only 2.5 s. Ultrasonic energy instrument
tips had the highest temperature increase (173°C),
increasing tissue temperature the most (58°C at 5 s) and for
the longest interval after activation (24°C at 20 s).
Residual heat is one of five described patterns of lapa-
roscopic energy complications. The other four are insula-
tion failure, capacitive coupling, direct coupling, and direct
application [4–6]. Previous studies have investigated peak
temperatures of laparoscopic instruments [7] and the ther-
mal spread during activation of these instruments [8].
However, the most clinically relevant information for a
surgeon is an understanding of how long he or she must
wait before touching additional tissue after activation of an
energy device is completed.
The importance of the current study is the acknowl-
edgment that laparoscopic energy instruments retain a
significant amount of heat after completion of energy
activation. In fact, this residual heat is sufficiently high to
raise the temperature of additional tissue enough to cause
injury. We defined a temperature change of 20°C from
baseline to be clinically significant, an estimate that may be
too conservative. Previous work has shown that tempera-
ture increases exceeding 42°C, or about 5°C from baseline,
causes damage to both cell membranes and denatures
proteins [9–11]. However, the clinical relevance of
increased tissue temperature depends on both the maxi-
mum temperature and the length of time the tissue is
exposed to elevated temperature.
The current study found that an increase of tissue tem-
perature by more than 20°C occurred with three instru-
ments (ultrasonic, bipolar tissue fusion, and monopolar
devices) 2.5 s after activation and that ultrasonic instru-
ment tips raised tissue temperature more than 20°C even
20 s after activation. This information is important to
laparoscopic surgeons because it highlights the fact that
these common energy instruments require time to cool
between activations.
This study had three main limitations. First, the tissue
used was cadaveric bovine tissue stored at room tempera-
ture. As a result, the baseline tissue temperature was
10–15°C cooler than body temperature, and our model did
not account for blood flow. Second, this study used the
thermography temperature differential as the primary out-
come measure. The clinical relevance of increased tem-
perature measured by thermography is less certain than
histology or an in vivo animal survival model, in which
residual instrument temperature on the bowel can be fol-
lowed for a clinically relevant outcome such as perforation.
Third, we used only one instrument at one energy setting
with a one-time pattern of activation from each of the four
categories of energy devices. Therefore, we cannot
Fig. 2 Increased tissue
temperature at varying intervals
after energy activation
Surg Endosc (2011) 25:3499–3502 3501
123
Comparison of Properties of Major Energy
Devices
BurstPressure
Studiesshowthatadvancedbipolardevicescanseal
vesselsupto7mmindiameter8
andthatthese“sealed”
vesselscanwithstandupto3timesnormal-rangesys-
tolicbloodpressure.20
Theburstpressuresachieved
withthesetechnologiesisgenerallynotashighasthat
achievedwithtraditionallaparoscopicstaplingdevices
andclips,44,45
althoughthisdifferenceshouldnotbe
clinicallysignificant,consideringthattheburstpres-
suresachievedarestillsupraphysiological.Aslongas
theburstpressureisinthesupraphysiologicalrange,
withareasonablebuffer,itdoesnotmakeanyclinical
significanceastowhethertheburstpressureis300or
400mmHg.
Supraphysiologicalburstpressures,however,donot
guaranteeagainstfailureoftheseal.Forexample,even
thoughthePlasmaTrissectorwasreportedtohavea
meanburstpressureof322.7mmHgforsealing6-to
7-mmvessels,thesealfailureratewasreportedas92%,
withthefailureratedeterminedbydividingthenumber
ofsealfailuresbythetotalnumberofattemptedseals
requiredtoobtain13sealsforburstpressuretesting.8
AnindependentcomparisonofHarmonicACE,
LigaSure,GyrusPK,andEnSealhasbeenreportedin
sealing5-mmvesselsinasimulatedlaparoscopicenvi-
ronment(Table4).20
Inthisstudy,theLigaSurehada
highermeanburstpressurethanGyrusPK.However,
otherstudiesshowconflictingresults,andastudyspon-
soredbythemanufacturersofEnSealfoundthatEnSeal
hadsignificantlyhigherburstpressuresthanothervessel
sealers.46,47
SealTime
Sealtimeisdefinedasthetimedurationbetween
deviceactivationandwhenthedevicegivesasignal
indicatingthatthevesselissealed.TheLigaSureand
GyrusPKhadtheshortestvessel-sealingtime.20
How-
ever,in3of10applicationsoftheGyrusPKinthis
study,thevesselwasfoundtobecompletelyopenwhen
itwastransected,despitethesignalfromthedevice
indicatingthatthevesselissealed.Therefore,while
havingashortersealtimeshouldtheoreticallyreduce
theoveralloperatingtime,thismaynotbetruein
practiceifvesselsarenotreliablysealed,andextratime
needstobespenttoidentifyandcontrolbleedingfrom
inadequatelysealedvessels.
LateralThermalSpread
Itisreportedthattemperaturesabove42°Cmay
causetissuedamage,6,48
demonstratedhistologically
inaratmodel.49
Theuseofallinstrumentsutilizing
TABLE 4
Comparison of Properties of Major Energy Devices
Monopolar Standard Bipolar Plasma Kinetic LigaSure EnSeal Ultrasonic
FDA-Approved Maximum Vessel Size Not specified Not specified 7 mm 7 mm 7 mm 7 mm*
Lateral thermal spread; distance Not well assessed
(multiple variables)50,53
;
0.331–0.592 mm53
Not well assessed
(multiple variables);
2–22 mm44,64,65
1.5–3.2 mm66
1.8 mm (10 mm
LigaSure); 1.2–4.4 mm
(5-mm LigaSure)54,66
0.98 mm55
0–3 mm53,64,67,68
;
up to 25 mm with
continuous dissection
for 10–15 s at the
highest setting69
Mean maximum temperature at 2 mm
laterally,20
°C
— — 64.5 ± 2.7 55.5 ± 2.4 58.9 ± 2.6 49.9 ± 1.8
Seal time,20
s — — 11.1 ± 1.0 10.0 ± 0.9 19.2 ± 1.1 14.3 ± 1.0
Mean burst pressure,20
mm Hg — — 290 ± 110 385 ± 76 255 ± 80 204 ± 59
Smoke/vapor plume,20
ppm — — 74.1 ± 11.9 12.5 ± 3.6 21.6 ± 5.6 2.88 ± 0.6
*All ultrasonic laparoscopic energy sources are FDA approved for sealing vessels up to 5 mm, except for Harmonic ACE+7 which is approved for up to 7-mm vessels.
772ObstetricalandGynecologicalSurvey
Copyright©2014LippincottWilliamsWilkins.Unauthorizedreproductionofthisarticleisprohibited.
OBSTETRICAL AND GYNECOLOGICAL SURVEY 2014 Volume 69, Number 12: 763-776
A comparison of the advanced bipolar and
ultrasonic laparoscopic vessel sealers
sources [11] although the smoke plume from these devices
may still significantly obscure the surgeon’s view [18]. The
tips of the Harmonic ACE are more effective for dissection
than the Harmonic Scalpel but overall may have more limited
dissection capability when compared with monopolar scis-
sors and conventional bipolar forceps [13].
Comparison of Advanced Bipolar and Ultrasonic Vessel
Sealing Technologies
The reasons for a surgeon’s preference for a particular
laparoscopic energy source may be many and varied. A com-
mon reason for choosing a particular instrument is the sur-
geon’s own experience with that instrument that may have
been preordained by a mentor during surgical training. Un-
familiar technologies often are not trialed. Surgeons are
also subjected to marketing strategies and even inducements.
Indeed, device manufacturers sponsor many of the studies on
energy sources published in the medical literature. To com-
plicate matters further, it is generally not possible to com-
pare vessel sealing data from different studies because
study conditions may vary widely. Hence, it is difficult for
spread generally seems to be less with ultrasonic devices
[20,21] although the time of activation with this
technology, and the resultant amount of lateral spread, are
operator dependent. Interestingly, the residual temperature
of the instrument tip after activation is less with bipolar
devices [22]. As a general principle, tissue should not be
grasped with any energy source immediately after activation.
Particulate formation is less with ultrasonic devices although
all laparoscopic energy sources produce a plume of smoke or
steam [16]. In summary, there is insufficient evidence for one
vessel sealing technology to be considered superior to the
other. A detailed critical evaluation of comparative clinical,
laboratory, and animal studies of all classes of laparoscopic
energy sources is available elsewhere [6].
Devices have recently been developed that combine bipo-
lar vessel sealing and bipolar tissue transection (PKS Omni,
Gyrus ACMI), monopolar and bipolar electrosurgery
(LigaSure Advance, Covidien; Fig. 7), and ultrasonic and bi-
polar technologies (Thunderbeat, Olympus America; Fig. 8)
into a single instrument. Although it is desirable to incorpo-
rate multiple functionalities into 1 handpiece so that ‘‘instru-
ment traffic’’ can be minimized, it is important not to
compromise the functionality of individual technologies
for the sake of efficiency. A single laparoscopic energy
source that can produce all the tissue effects available
with individual energy sources may become a reality for
the future laparoscopic surgeon. Along with ultrasonic
and electrosurgical modalities, the ‘‘ideal laparoscopic
Table 3
A comparison of the advanced bipolar and ultrasonic laparoscopic
vessel sealers [1,3,6,11,19–22]
Parameter
Energy source
Advanced bipolar Ultrasonic
Vessel sealing: maximum
vessel diameter
Superior (7 mm) Inferior (5 mm)
Vessel sealing: time to seal Equal Equal
Lateral thermal spread* Inferior Superior
Residual instrument tip
temperature
Superior Inferior
Smoke/vapor plume Inferior Superior
* The time of activation for ultrasonic vessel sealing is operator-dependent so
the degree of lateral thermal spread may vary.
Fig. 7
The LigaSure Advance device incorporates advanced bipolar vessel
sealing and a blade for tissue transection, as well as a monopolar elec-
trode (visible at the distal end of the blue jaw) for extra dissection capa-
bility.
306 Journal of Minimally Invasive Gynecology, Vol 20, No 3, May/June 2013
Journal of Minimally Invasive Gynecology (2013) 20, 301–307
Acomparison ofmean burst pressures forsmall-, medium-,
and large-diametervessels amongthevessel sealingdevices
The mean seal times were highly variable among instru-
ments and tended to increase with increasing vessel
diameter (Fig. 3). Seal times were significantly shorter for
every vessel size when FT was compared with LS
(Table 1). The shortest seal times for 2–3 mm vessels were
observed with GP (1.36 s) and the highest with HS (4.07 s,
p 0.05) and LS (4.07 s, p 0.05). The shortest sealing
times for medium and large vessel sizes were observed
with the FT (3 s for 4–5 mm vessels and 3.54 s for
6–7 mm vessels). The highest seal time for medium vessels
was observed with the LS (7.2 s, p 0.05 compared with
FT, HS, PK, and GP), and the longest seal time for large
vessels was observed with the RX (8.25 s, p 0.05 com-
pared with FT, PK, HS, and GP). RX had the longest seal
time (6.35 s), and FT had the shortest seal time (3.13 s)
when all vessel sizes B7 mm were averaged together.
The percentage failure rates were highly variable among
instruments and tended to increase with increasing vessel
diameter (Fig. 4). Surgical clips and FT had no recorded
failures for any vessel size. The highest percentage failure
rate for each vessel size was observed with GP (54% for
2–3 mm vessels, 48% for 4–5 mm vessels, and 92% for
6–7 mm vessels). No significant difference in failure rate
was observed for 2–3 mm vessels among instruments tes-
cells at the sealed end. Increased coagulation necrosis was
seen with GP compared with the other devices. Apposition
of nucleated cells and minimal thermal spread was
observed with LS and FT (Figs. 5A–E and 6).
Discussion
The 5-mm laparoscopic instruments compared in this
experiment are currently available for clinical use and are
Food and Drug Administration (FDA) approved for sealing
vessels up to 7 mm in diameter, with the exception of the
HS, which is approved for sealing vessels up to 5 mm in
diameter. The HS uses a piezoelectric ceramic to convert
electrical impulses to mechanical energy at the active tip,
which vibrates at 55,000 cycles per second and can be set
at various excursion distances (power) for modification of
cutting and coagulation. Seals created with the HS are
formed by breaking hydrogen bonds between tissue pro-
teins, producing a coagulum with a water vapor by-product
[4]. The PK, GP, and LS are pulsatile, impedance-con-
trolled, bipolar electrosurgical instruments. The PK and GP
deliver energy to the tissue using a proprietary radiofre-
quency waveform to create a broad range of tissue effects.
Fig. 2 A comparison of mean
burst pressures for small-,
medium-, and large-diameter
vessels among the vessel sealing
devices
92 Surg Endosc (2009) 23:90–96
Surg Endosc (2009) 23:90–96

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