Surgical Energy

- DR. PRASHANT SHARMA
SURGICAL ENERGY
DR. PRASHANT SHARMA

INTRODUCTION
 Surgical energy is an essential part of every operation; yet, the basic principles and application
remain poorly understood among surgeons of all ages and experiences.
 Electrosurgical injuries account for over 5% of all laparoscopic complications and can result in
severe disability or death as well as a source litigation.
 Public awareness of surgical energy complications significantly increased following the 2010
death of Pennsylvania Congressman John Murtha likely secondary to an electrosurgical injury.
 To combat the widespread lack of in-depth knowledge, the Society of American Gastrointestinal
and Endoscopic Surgeons developed the Fundamental Use of Surgical Energy (FUSE) curricula
and certification.
• The FUSE curriculum has proven robust especially when accompanied by an interactive
component and is being rapidly accepted and applied internationally.

TYPES OF ENERGY IN THE OPERATING ROOM
1. MONOPOLAR RADIOFREQUENCY ENERGY
 The most common device in today’s operating room is based upon the monopolar
device originally popularized by Dr. William Bovie and Dr. Harvey Cushing in the
1920s.
 The “Bovie,” as it is commonly called in North American surgical suites, is a highly
versatile device that is used in open surgery, laparoscopy, and endoscopy and
permeates through all surgical specialties.
 When activated, the electrosurgical unit (ESU) converts 60 Hz alternating current
from an electrical outlet to approximately 500,000 Hz of radiofrequency energy.
 This travels from the tip of the instrument, through the tissue, and into the patient and
returns to the ESU via a dispersive electrode or “grounding pad”.

 Varying the duration of energy discharged (i.e., selecting “cut,” “coag,” or “blend” mode) from
the generator as well as the proximity of the tip to the tissue (e.g., current density) creates
three different clinic effects:
1. Vaporization (Cutting),
2. Desiccation (Coagulation),
3. Fulguration (Spraying).
 VAPORIZATION (CUTTING) MODE
 To cut or vaporize tissue, a low voltage/high current mode is selected (i.e., cut mode).
 This is combined with a surgical technique that creates high current density (treating a small
amount of tissue near the thin tip of the instrument) during activation.
 This focuses energy on a small area of tissue resulting in rapid heating of the cells to the
boiling point. Linear movement of the instrument cuts tissue with less than 200 μm of lateral
thermal injury.

 DESSICATION (COAGULATION) MODE
 To achieve more coagulative effect yet still move through tissue, a high voltage/low current
mode is typically selected (coag mode) and the current density reduced by increasing the area
of tissue contact with the instrument.
 This raises cell temperatures more slowly to 60° to 95°C which results in protein coagulation
or “desiccation,” as opposed to vaporization.
 A “blended” mode is a combination of the cut and coag waveforms which seeks to maximize
energy effectiveness by creating a safer, low voltage mode that can both cut and coagulate
tissue.
Desiccation of tissue with the coag mode is an effective way to increase coagulation during
dissection but should not be used for vessel sealing.
 Vessel sealing is better accomplished in cut mode while grasping and occluding the vessel
with forceps. The apparent paradox (“cut” mode is more effective than “coag” mode for vessel
sealing) is due to the fact that the continuous cut waveform more evenly heats tissues for a
homogenous vessel seal as it cannot vaporize the cells due to the low current density created
by the relatively large amount of tissue held between the tips of the tissue forceps.

 FULGURATION (SPRAYING) MODE
 Superficial coagulation or “fulguration” is achieved most commonly in a high voltage/low current
flow mode (coag mode) while holding the instrument close but not contacting the tissue. Energy
can then arc to the superficial tissues creating temperatures in excess of 200°C.
 The low current density rapidly heats and cools cells creating black eschar as a result of the
breakdown of elements, especially carbon, into their atomic components.
Thermal penetration is typically 5 mm or less.
 The versatility and effectiveness of monopolar radiofrequency energy in surgery continues to
increase as alternative modes and techniques of operation emerge.
 Energy devices and generators that continuously monitor tissue effect during activation are
already available.
 When combined, these new devices and techniques all bring the surgeon closer to the ultimate
goal of energy application: the ability to utilize the smallest amount of energy possible to create
the desired tissue effect.

2. BIPOLAR RADIOFREQUENCY ENERGY
 Bipolar devices contain both limbs of the electrical circuit in a single device so as to focus
radiofrequency energy solely on the tissue between the instrument’s tips.
 This reduces the required voltage from 1,400 to 9,000 V during monopolar energy use to
approximately 100 to 200 V.
 Basic bipolar devices are designed for coagulation of tissue alone; however, newer devices
are available that have added a cutting blade to transect tissue.
 These “advanced” bipolar devices often include tissue feedback mechanisms and audible
tones to notify the surgeon when the tissue is ready for transection.
 This slightly increase operative time and smoke production when compared to other
devices but has the benefit of consistently sealing vessels up to 7 mm in diameter.
Bipolar energy is highly useful while operating on delicate tissues and in the tissues with
high neural density. e.g. during Thyroidectomy

3. ULTRASONIC ENERGY
 Ultrasonic devices convert low-voltage radiofrequency energy into high frequency
(approximately 44,000 Hz) mechanical vibrations via piezoelectric crystals in the device
handle.
 These rapid vibrations generate friction that heats tissue, denatures proteins (coagulates), and
creates tissue separation (cuts) at temperatures below boiling.
 A transient mist is formed due to the cavitation effect of the vibration but minimal charring
(tissue temperatures do not exceed 100°C) and lateral thermal spread is seen on low settings.
 This facilitates dissection and decreases operative time in contrast to monopolar and bipolar
instruments.
 Ultrasonic devices can effectively seal vascular structures up to 3 mm in size although newer
devices can reportedly seal larger vessels by increasing dwell time.
A Harmonic Scalpel is the device that works on this principle and is widely used in surgical
practice now.

4. PLASMA ENERGY
 Radiofrequency energy can be applied in short, 40 μs bursts to create plasma energy along
the edge of a device.
 Plasma energy can also be carried onto the tissue itself by an inert gas, most commonly,
argon.
 When combined with short bursts of high-voltage radiofrequency energy, plasma energy can
provide tissue cutting and coagulation functions with minimal thermal spread.
 Argon plasma coagulators are thus designed for the superficial coagulation of diffusely
bleeding tissue (e.g., cut liver or spleen).
 They are highly effective in a bleeding or debris-filled field and produce less smoke than
monopolar or bipolar devices with a constant thermal spread of 2 to 3 mm.
 However, intravascular embolism of insoluble argon gas has resulted in cardiac arrest and
death; thus, avoidance of direct tissue contact and minimal gas flow volume is recommended.

5. LASER ENERGY
 Lasers generate heat by focusing a concentrated beam of light on tissue.
 They can be used for both cutting and coagulating tissue and were quite common in the 1980s
and early 1990s.
 Due to their high cost, need for specialized training and general increase in operating times
lasers have been relegated to use in limited, specific scenarios. e.g. Hemorrhoid laser surgery.
 Precise control of the depth of penetration promotes their continued use in dental, eye,
cosmetic, anorectal and gynecologic fertility procedures.

6. MICROWAVE AND RADIOFREQUENCY ENERGY ABLATION
• Microwave or radiofrequency energy can be applied directly to tissue to induce necrosis in
either an open or percutaneous fashion.
• The goal of this directed use is typically tumor necrosis or arrhythmia ablation.
 Radiofrequency ablation devices take many different forms (bipolar, monopolar, internally
cooled, etc.) and function via the principles of monopolar and bipolar energy discussed above.
• Significantly larger amounts of radiofrequency energy are used and extra care should be taken
to decrease the risk of electrosurgical complication.
 Microwave ablation devices function within a different part of the electromagnetic spectrum
(frequencies between 915 MHz and 9.2 GHz) and create tissue effect via dielectric heating.
• The microwave energy causes rapid alternation of the positive and negative poles within cells.
The charged ions (especially water) rotate every time the positive and negative poles switch
polarity (approximately 109 times per second) and this creates rapid and uniform heating of
cells within the microwave field.
No dispersive electrode is needed as no circuit is created—heating is a direct result of the
microwave energy on the cells.

• Both radiofrequency energy and microwave ablation are susceptible to nearby perfusion which
can reduce complete ablation rates.
• Radiofrequency energy will follow the path of least resistance as it travels to the dispersive
electrode so nearby vasculature, bile ducts, lymphatics, and so forth can serve as an “electric
sink.”
• Microwave ablation can also be affected by nearby perfusion acting as a “thermal sink.” As no
circuit is created, no electrons are stolen but the constant flow of liquid removes heat just as an
automobile radiator cools an engine.
A distinct benefit of microwave ablation is the ability to achieve high tissue temperatures (150°C)
in contrast to the 60° to 100°C limit that guides energy flow during radiofrequency energy ablation.
This can result in shorter ablation times (typically 4 to 10 minutes).
 Both modalities can be successfully used to achieve complete tumor ablation and use is often
guided by availability and experience.
 All surgeons should be aware of the different mechanisms of action in order to minimize the risk of
electrosurgical complication.
 Due to each device’s complexity and relative rarity of use, utilization with imaging guidance and
manufacturer assistance is recommended.

NEW TECHNIQUES AND INSTRUMENTS
VESSEL SEALING TECHNOLOGY
• Combination of pressure and energy to create a seal.
• Feedback controlled output so reliable seal in minimal time
• Seals vessels up to 7 mm with a single activation.
• Seal strength comparable to sutures/clips, can withstand >3 times
normal pressure
• Lateral thermal spread :
 LIGASURE: 0 - 4.5 mm
 ENSEAL TRIO: 1 mm

LIGASURE
Combination of Press Advance Bipolar
Device.
Pressure and Energy.
Feedback Controlled System.
 Rachet Grips Vessels tightly.
 Measures resistance in tissue
and sends to generator.
 Continues till vessel is sealed.

• Seal time: 2-4 seconds
• Seals vessel upto 7 mm
• Tolerates 3 times SBP
• Max. Temperature 60-90⁰C
• Thermal Spread 4.5 mm

ENSEAL
Only System Control energy deposition.
Nanopolar thermostat in jaws.
Adjusts energy according to tissue
impedance.
Less heat required:
Tissue Volume reduced by
compression.

THUNDERBEAT™
 World’s 1st and only integrated
energy system.
 Integration of ultrasonic and bipolar
technology.
 Rapid cutting of tissues with ultrasonic
energy and sealing of vessel with
bipolar energy.
 Minimal thermal spread.
 Improved visibility due to reduced
mist.
 Allows upto7 mm sealing.
 Precise dissection.

THE EIGHT REPRODUCIBLE PATTERNS OF ELECTROSURGICAL
INJURY
 Energy-based device have become ubiquitous in the contemporary operative room.
 Increasing use has resulted in more complications that adhere to eight common patterns of
injury:
1. Fires,
2. Antenna Coupling,
3. Insulation Failure,
4. Residual Heat,
5. Direct Application Interaction With Electronic Devices,
6. Direct Coupling, And
7. Capacitive Coupling

 Fires
 Operating room fires and explosions are fortunately rare events (550 to 650 per year) but can
result in significant injury or death.
 In order for a fire to occur, three elements must be present:
1. Heat or an ignition source (i.e., surgical energy, patient or fluid warmer),
2. Fuel (alcohol-based prep, surgical drapes, etc.), and
3. Oxygen.
• The majority of surgical fires occur in the airway (21%) or around the upper chest, head, and
neck (44%) likely due to increased oxygen content.
• Utilization of closed breathing circuits (i.e., endotracheal tube) as opposed to nasal cannula or
mask oxygenation as well as maintaining oxygen content at ≤30% will minimize risk.
 Should a fire or explosion happen the following steps should be immediately undertaken:
1. Stop the flow of all airway gases and disconnect the patient from the breathing circuit including
removing the endotracheal tube during an airway fire;
2. Remove any burning or burned materials;
3. Extinguish the fire from the burning materials by dousing it with saline, smothering it or utilizing
a carbon dioxide fire extinguisher.

If the fire is not contained by these steps then practitioners should follow the acronym:
 RACE:
 Rescue; attempt to rescue the patient or staff.
 Alert; activate the fire alarm and alert nearby staff.
 Confine; isolate the fire by closing doors, shutting of medical gas and electrical power.
 Evacuate; evacuate the incident room and entire surgical suite if necessary.
 Preventative Strategies:
 Education of the surgeon and operating room staff on the three elements needed for fire
creation taking special note of oxygen-rich environments such as the airway or under surgical
drapes.
 Do not place surgical drapes until alcohol-based preps are completely dry without pooling
 Enter the airway with cold surgical instruments with the patient on the minimal amount of
oxygen enrichment necessary to maintain appropriate saturations (goal oxygen content
<30%).
 Maintain the fiber optic light in stand-by or “off” mode any time that it is not connected to the
laparoscopic telescope.

 Antenna Coupling
 Electrosurgical injury due to antenna coupling has only recently been elucidated but is thought
to be a major source of thermal injury.
 Radiofrequency energy, most commonly from the wire/cable of monopolar devices, can be
transmitted into the air (through intact insulation) and into nearby conductors (cables,
instruments, or monitoring electrodes).
 Antenna coupling is one of the most ubiquitous sources of electrosurgical complications during
monopolar energy use as any wire/cable that lay within close proximity of the “Bovie” cord (or
return electrode cord) will pick up stray energy and can burn the patient.
 Close proximity and parallel alignment of instruments/wires/cables has also been shown to
increase tissue temperatures nearly 60°C.
 The forced parallel alignment and close proximity of Single Incision Laparoscopic Surgery
(SILS) also increases antenna coupling and the resultant thermal injuries may be an explanation
for the increased postoperative hernias and incisional pain.
 The simple maneuver of separating the cords has been consistently shown in benchtop and in
vivo trials to reduce the incidence of antenna coupling.

1. Separate the active electrode and dispersive electrode cords from other nearby wires/cords.
2. Minimize voltage by decreasing power, using lower power modes (cut or blend), or switching
to lower power bipolar/ultrasonic devices.
3. Avoid use of monopolar energy during single incision laparoscopic surgery.

 Insulation Failure
 Electrosurgical injury via insulation failure is thought to be one of the most common causes
of inadvertent thermal injury during laparoscopy.
 It may also be the most easily managed. Insulation defects can be found in up to 39% of
monopolar instruments, typically near the instrument tip as the insulation begins to thin and
taper.
 Interestingly, these defects (and resultant injuries) are more common during robotic surgery.
Unfortunately, just 10% of insulation defects are visible to the naked eye; thus, some authors
suggest routine use of porosity detectors during sterile processing of laparoscopic
instruments.
1. Careful inspection of the instrument prior to use for obvious breaks in insulation.
2. Maximize visualization of entire instrument during activation to identify aberrant energy
arcs. For laparoscopy and endoscopy this often requires pulling the telescope back into
the port or out of the patient to see the “big picture.”
3. Routine porosity detection of reusable laparoscopic instruments including any devices that
may be connected to energy (e.g., L-hook, spatula, graspers, and/or scissors).

 Residual Heat
• Residual heat is defined as the increased instrument temperature after energy activation is
completed.
• The rate of increase and maximal instrument temperature is unique to each device and
causes injury when the tip touches tissue prior to complete heat dissipation.
• This is most commonly seen with ultrasonic devices which reach higher maximum
temperature (>200°C) and remain hot longer than bipolar or monopolar devices.
 Clinical Example:
• During laparoscopic hemi-colectomy, the ultrasonic device is used to transect the
transverse mesocolon and then immediately used to grasp/retract small bowel resulting in a
full thickness injury and delayed perforation.
 Delay use of ultrasonic devices for grasping or dissecting until at least 5 seconds have
passed after activation (2 seconds for advanced bipolar and monopolar devices).

 Direct Application
 Electrosurgical injury via direct application is a result of unintentional activation of any type of
instrument while contacting tissue.
 Clinical Examples:
1. While leaning against the patient, the surgeon unintentionally activates the monopolar
device resulting in a burn to the patient at a site remote from the surgery.
2. The monopolar “bovie” is activated directly on the staple line of an intestinal anastomosis
and focuses on a single staple resulting in enormous current density and melting of the
staple with staple-line breakdown
1. Routine use of protective “holsters” or “sleeves” when devices are not in use.
2. Activate devices with the tips fully visualized and containing only the tissue intended to
coagulate and/or cut.
3. Understand the activation cycle of each device.

 Interaction With Electronic Devices
 Radiofrequency energy transmitted through the air interferes with nearby monitoring
devices such as ECG leads, neuro-monitoring devices, and even implanted cardiac
devices.
 The transfer of energy into monitoring cables hampers waveform interpretation and can
cause direct thermal injury via antenna coupling.
 In addition, the transferred energy can interfere with implanted cardiac device sensing and
cause malfunction.
1. Utilize low power settings or low energy devices (bipolar, ultrasonic) when operating on
patients with implanted cardiac devices.
2. Avoid use of energy devices near or parallel to the implantable device current vector.

 Direct Coupling
 Direct coupling is intentionally created when the surgeon touches the monopolar device to a
forceps or other conductor while grasping tissue to coagulate.
 Complications arise when energy is unintentionally transferred to a nonelectrically active
conductor.
Clinical Examples:
1. A monopolar instrument with an extension is activated in the pelvis while unintentionally
touching a forceps that is retracting the ureter during a low anterior resection resulting in
delayed ureteral injury.
2. A monopolar, laparoscopic L-hook is activated near the tip of the metal suction–irrigation
resulting in energy transfer to the suction tip and into unintended tissue.
1. Avoid contact with other conductive instruments prior to activation.
2. Maintain complete visualization of the monopolar electrode in contact with the tissue.

 Capacitive Coupling
 Capacitance is stored electric charge when two conductors are separated by an insulator.
 This stored energy can be transferred, through intact insulation, into nearby conductors
(such as the bowel) resulting in thermal injury. Capacitive coupling occurs almost
exclusively with monopolar energy use due to its high voltage.
 Clinical Examples:
1. The laparoscopic monopolar L-hook is activated and capacitive energy is discharged
directly into bowel contacting the insulated shaft of the instrument resulting in a delayed
bowel injury.
2. Prior to the development of video cameras for laparoscopy, surgeons looking directly
through the eyepiece of the laparoendoscope would suffer burns to their eyes due to
capacitive coupling.
1. Utilize lowest power setting to achieve effect or low energy devices (bipolar, ultrasonic).
2. Avoid the use of combined metal/plastic laparoscopic trocars.
3. Maintain complete visualization of instruments during energy activation.

CONCLUSION
The best energy device for a particular patient and surgery is dependent on a multitude of factors.
The characteristics of each energy device should be considered in addition to other factors such
as device availability and user experience which are not universally quantifiable.
Monopolar energy remains the most common and versatile instrument in the surgeon’s energy
armamentarium.
It is everyone’s responsibility in the operating room to understand how electro-surgery works and
to take steps to ensure the patient’s safety.
As our understanding of surgical energy device function increases so should the safety of our
operating rooms.
Choosing the right tool for the job requires an evidence-based approach as well as lifelong
learning.

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