Uro instruments- energy modalities

Dept of Urology
Govt Royapettah Hospital and Kilpauk Medical College
Chennai
1

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Moderators:
Professors:
 Prof. Dr. G. Sivasankar, M.S., M.Ch.,
 Prof. Dr. A. Senthilvel, M.S., M.Ch.,
Asst Professors:
 Dr. J. Sivabalan, M.S., M.Ch.,
 Dr. R. Bhargavi, M.S., M.Ch.,
 Dr. S. Raju, M.S., M.Ch.,
 Dr. K. Muthurathinam, M.S., M.Ch.,
 Dr. D. Tamilselvan, M.S., M.Ch.,
 Dr. K. Senthilkumar, M.S., M.Ch.
Dept Of Urology, KMC and GRH,
Chennai
2

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 Electrosurgery is the application of electrical current
to tissue to achieve the effects of cutting, coagulation,
desiccation, or fulguration.
 In the 1920s, Bovie, an electrical engineer at the
Massachusetts Institute of Technology, developed a
cutting loop that delivered electrical energy.
 On October 1, 1926, at the Peter Bent Brigham
Hospital in Boston, used the device to remove a
highly vascular myeloma from the head of a patient
that previously had been deemed inoperable.
History
Chennai
3

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 A typical electrosurgical generator takes our household current of 60
cycles/second and raises the frequency to 200,000 cycles/second. Such
high frequencies are radio frequencies, when current passes at such
high frequency through the human body no neuromuscular
stimulation occurs and patient does not get an electric shock.
Electrosurgical
Generator
Chennai
4

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 For coagulation to occur, the current is interrupted
approximately 30,000 times per second, cells are allowed
to cool as the energy cycle is off and the cells dry out
instead of rupturing.
 For cutting current, the radiofrequency current is
delivered continuously, the cells rapidly heat up to the
point of boiling and rupture.
 Blended cutting, which adds some coagulation properties
to the cutting current
 Fulguration results when the electrode is placed about 2
to 5 mm from the tissue.
Monopolar
Electrosurgery
Chennai
5

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Chennai
6

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 Cutting current will penetrate deeper and
coagulation current will have lateral spread.
Chennai
7

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 Traditional monopolar devices do not work well in a
liquid environment.
 It works by adding a column of argon gas
 Electrosurgical energy then ionizes the argon gas
and helps to displace the blood in the surgical field.
 Because it is a noble gas, the current from the
electrode is effectively transmitted to the underlying
tissue.
Argon Beam Coagulator
Chennai
8

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 The incidence of electrosurgical injuries is estimated
to be 2 to 5 per 1000.
 During monopolar electrosurgery, the patient is part
of a complete electrical circuit.
 In patients with pacemakers, the manufacturer
should be consulted before surgery involving
monopolar cautery to ensure that interference with
the devices does not occur during surgery. The
devices may need to be temporarily deactivated
during the procedure.
Safety
Chennai
9

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 Prosthetic joints can also affect current conduction
but are not an absolute contraindication to use of
monopolar cautery. Ideally, the direct path of the
electrical circuit should be directed away from the
prosthetic joint. For example, if the patient has a
right hip prosthesis, the dispersion electrode pad
should be placed on the contralateral hip
 Insulation failures can occur.
 The surgeon is also at risk for electrosurgical burns
particularly when gloves are wet as they do not
afford enough protection.
Safety
Chennai
10

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 Direct coupling: When the activated active electrode
touches a nearby metallic instrument it energizes it
and this stray energy may find its way to the patient
plate causing injury.
Safety
Chennai
11

Direct coupling
Like if a monopolar hook
touches a laparoscopic
telescope, if the telescope
is in turn in contact with
bowel. The energized
telescope will cause
thermal injury to the
bowel.
Chennai
12

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 Use lowest possible setting and increase the energy as per
need.
 Electrode tip can become coated with eschar, which
causes an increase in impedance.
 A common technique during open surgical procedures is
for the surgeon to grasp a bleeding vessel with a forceps
or hemostat and then have the assistant touch the
instrument with the activated electrode of the Bovie.
During these maneuvers, the surgeon must be careful not
to touch the patient with his or her free hand. Doing so
would create an alternative circuit that could allow the
current to travel to a different part of the patient's body.
General Safety Tips
Chennai
13

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 Patient pad placement: Patient plate should be in
contact over a large surface area at least 100 square
cm.
 One should avoid bony prominences; Soft pads are
better than metallic plates as they give uniform area
of contact.
 The pads should be placed near the area of interest
General Safety Tips
Chennai
14

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 To keep the operating field neatly organized and not
tangling cords when multiple corded instruments
are used.
 Care should be taken not to wrap cords around
metal instruments because insulation defects could
lead to burns.
General Safety Tips
Chennai
15

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 Active and return electrodes are integrated in the
delivery hand piece.
 Bipolar “vessel sealing” devices have been
developed that use computing technology built into
the electrosurgical generators.
 Vascular structures up to 7 mm in diameter to be
fused and can help obviate the need for sutures,
clips, or surgical staple
Bipolar Devices
Chennai
16

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 It combines pressure and energy to create a seal.
 Ligasure uses higher current and lower voltage (180
V ) along with optimal pressure delivery by the
instruments.
 It has a feedback control mechanism, which gives an
alarm once the tissue is adequately sealed.
 It has minimal thermal spread and the seal site is
often translucent, this allows the surgeon to look for
hemostasis prior to cutting the tissue
Ligasure
Chennai
17

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 Sealed blood vessel can with stand a rise in blood
pressure equal to three times, the systolic pressure.
 Sealing tissue and blood vessels with this device is
as effective as suture ligation or clip application.
Ligasure
Chennai
18

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Chennai
19

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 It is based on principle of vapor pulse coagulation (VPC).
 On application of the energy, tissue fluid boils producing steam
which form vapor pockets, these vapor pockets coalesce to form
vapor zones. This heating of the tissue causes denaturing of
vessel wall protein and coagulum formation, which occludes
the vessel lumen, pulse-off periods allow tissue for cooling and
moisture to return to the targeted area, greatly reducing hot
spots and coagulum formation.
 The Gyrus PK system has its own generator, which works in
tandem with its own instruments. It has application in open
surgery, laparoscopy and robotic surgery.
 Separated instruments are developed for all types of surgery’s
but the generator can remain the same.
The Gyrus PK tissue
management system
Chennai
20

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Chennai
21

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Enseal
Chennai
22

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 It uses an advanced bipolar technology to seal the tissue within
the blades
 It uses the patented I Blade technology, which offers strong
uniform compression along the tissue sealing line.
 Enseal uses a smart electrode technology, which includes
numerous conductive particles embedded in a plate, which is
temperature-sensitive.
 Each of these particles acts like a discrete thermostatic switch to
regulate the quantity of current that passes into the tissues in
contact.
 Once the tissue starts heating above a critical level, these
nanoparticles interrupt the flow of current and when the
temperature dips below, the desired level they again reactivate the
current, this cycle is continued till desired temperature is reached
(temperature is regulated to a set level of 100°C.
Enseal
Chennai
23

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 Physics of ultrasound: Ultrasound is longitudinal wave,
whose frequency is above the audible range.
 High power ultrasound can be harnessed to produce
surgical cutting, coagulation, and dissection of tissues.
 Mechanical energy and heat are generated, and these
cause the denaturation of proteins and the formation of a
coagulum that can seal small vessels.
 Vessels 2 to 3 mm in diameter can be sealed, and vessels
up to 5 mm in diameter can be sealed with some newer
instruments.
 Aerosolized fatty droplets may develop as the tissue is
divided, and this can negatively affect visualization
through the laparoscope.(ex. Harmonic Scalpel)
Ultrasonic
Instrumentation
Chennai
24

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 Incisions made with the ultrasonically activated scalpel
or cold steel scalpel heal almost identically and, therefore,
are superior to electrosurgically made incisions.
 Heat generated using the harmonic is limited to
temperature below 80°C.
 This leads to reduced tissue charring and desiccation and
also minimizes the zone of thermal injury.
 Ultrasonic surgery causes slower coagulation than that
observed with either electrosurgery or laser surgery, but
is as effective.
Ultrasonic
Instrumentation
Chennai
25

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 A study comparing the vessel sealing times and thermal
spread of two bipolar vessel sealing systems (LigaSure
and PK [Gyrus ACMI, Southborough, MA]) and an
ultrasonic device (Harmonic Scalpel) was performed.
 This study demonstrated that the two bipolar systems
had faster vessel-sealing times with higher burst
pressures compared with the ultrasonic device.
 However, the ultrasonic device had less thermal spread
and smoke production (Lamberton et al, 2008).
 The smoke plume produced by ultrasonic devices may
also be less toxic compared with electrosurgically
generated smoke.
Comparison between Bipolar
and Ultrasonic device
Chennai
26

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 The ThunderbeatTM (Olympus), was the first
device to integrate the ultrasonic and advanced
bipolar generator. Both the generators can be used
interchangeably.
 Ethicon has also come up with an integrated
generator ETHICON ENDO-SURGERYTM
compatible with all harmonic and enseal devices.
 The sealing capabilities of this device is necessarily
same as ultrasonic or advanced bipolar depending
on the generator used.
Integrated Ultrasound and Advanced
Bipolar Generators
Chennai
27

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Device Safety(
Minimum
thermal Spread)
Vessel sealing
(efficacy on
vessls <7mm)
Utility (multiple
uses)
Harmonic
Scalpel
1 mm Poor Excellent
Gyrus PK 2-6 mm Poor Fair
Ligasure 2-3 mm Excellent Fair
Enseal 1 mm Excellent Poor
Chennai
28

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 Two electrodes are positioned at the tip of the probe,
creating a spark when triggered.
 Immersed in a liquid, the electrical spark creates an
immediate transition from fluid to gas, creating a
rapidly expanding plasma shockwave radiating from
the spark outward 360 degrees.
 The collapse of this shockwave creates a cavitation
bubble, which creates a secondary shockwave and
high-pressure microjets
Electrohydraulic
Lithotripsy
Chennai
29

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Electrohydraulic
Lithotripsy
Chennai
30

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 At less than 500 mJ, mucosal injuries are rare; at
greater than 1000 mJ, the risk of tissue damage is
increased.
 Because fluid vaporization provides the force
required for fragmentation, a small space between
the probe and stone is recommended during
fragmentation
Electrohydraulic
Lithotripsy
Chennai
31

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 Typically, 1 mm is required because increasing the probe-
to-stone distance leads to exponential decreases in
shockwave power.
 Probes between 1.9 and 3.3 Fr are available. Thinner
probes are considered more versatile because of their
application in flexible and semirigid ureteroscopy.
 A 1.9-Fr probe can be used with flexible ureteroscopy and
allows active deflection for acceptable rates of stone
fragmentation in all calyces
 Reducing probe diameter does not clearly lessen
fragmentation potential; however, durability is decreased
Electrohydraulic
Lithotripsy
Chennai
32

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 Chemical stone composition has been shown to
affect fragmentation efficiency during EHL
ureteroscopy.
 Uric acid stones required the most time, followed by
calcium oxalate monohydrate.
 This association may be due to the smooth outer
surface and lamination of uric acid stones being
more difficult for shockwave-generated
fragmentation.
Electrohydraulic
Lithotripsy
Chennai
33

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Pneumatic Lithotripsy
 Pneumatic lithotripsy uses ballistic forces to propel a
projectile against probe tip, thursting forward like a
piston.
 Either compressed gas (medical air or CO2
cartridges) or electromagnetic oscillations are used to
drive a projectile.
 When applied to compliant surfaces such as soft
tissue, the impact energy is absorbed and dispersed,
whereas rigid objects are not compliant resulting in
fracture.
Chennai
34

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 Pneumatic lithotripsy have been found to be useful
in large hard stones such as calcium oxalate
monohydrate and cystine stones.
 When increasing probe sizes at constant pressures (2
bar), incremental improvements in fragmentation
were noted (3 Fr = 14 min/g, 6 Fr = 6 min/g).
 Stone migration is a significant disadvantage when
treating ureteric stones with pneumatic lithotripsy.
Chennai
35

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 Pneumatic devices are the only modality not to cut
through wire. Most useful in Ureteroscopy where
guidewires and basket lie in close proximity to stone.
Chennai
36

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 Ellectric current is passed through pizo electric
crystal. It produces sound waves of 23,000 to 27,000
Hz. It is passed through metal probe which
fragments the stone.
 Instead of manually extracting fragments after
treatment, a central channel for suction provides
simultaneous stone debris aspiration during
lithotripsy
Ultrasonic Lithotripsy
Chennai
37

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 Ultrasonic fragmentation was found to reduce
operating times (from 210 minutes to 120 minutes),
admission times (from 7 days to 5 days), and
secondary interventions (from 50% to 20%), with a
much earlier return to normal physical activity (43
days vs. 9 days).
 Mucosal stripping occurs when suction is applied in
direct contact with urothelium.
Ultrasonic Lithotripsy
Chennai
38

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 Dual modality fragmentation with combined
ultrasonic lithotripsy and pneumatic lithotripsy
showed improved stone-free rates (92% vs. 85%
ultrasonography alone), fewer secondary
procedures, and decreased operative times, without
an increase in complication rates.
 When soft stones (e.g., struvite) are encountered,
complete fragmentation and suction removal of the
stone may be facilitated with ultrasonic lithotripsy.
 For harder stones, a drilling technique can be used to
fracture the stone into manually extractable stones.
Combined Ultrasonic and Pneumatic
Lithotripsy
Chennai
39

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 Using continuous irrigation and suction keeps the
probe tip cool, while continuously removing
particles.
 As the fluid is evacuated through the hand piece, it
cools the piezoceramic crystals.
 It is necessary to create a balance between suction
and irrigation. Air can be introduced if aspiration
outpaces irrigation and it can obscure the vision. It
can be managed by reducing suction presure,
increasing the height of irrigation ot intermittently
clamping the suction tubing.
Combined Ultrasonic and Pneumatic
Lithotripsy
Chennai
40

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 Laser lithotripsy can produce the smallest fragments
and is efficacious in all stone compositions.
 Ruby and Nd:YAG lasers use photoacoustic effect
where Light energy creates shock waves that
fragment the stone.
 With Holmium Laser photo thermal stone
breakdown occurs and it produces fine fragments
Laser Lithotripsy
Chennai
41

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 As a result of the relatively long pulse rate (250 to
350 μsec), the Ho:YAG laser is considerably less
efficient than other shorter pulse lasers like Er:YAG.
Laser Lithotripsy
Chennai
42

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 Er: YAG has longer wavelength( 2940 nm) and
shorter pulse rate compared to Holmium Laser.
 It has more photo acoustic effect compared to
Ho:YAG.
 Er: YAG forms torpedo shaped vapor bubble
between stone surface and probe where as in
Holmium laser it is Pear shaped with loss of energy
laterally producing weak shock waves that has
minimal effect on stone fracture.
Laser Lithotripsy
Chennai
43

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 Problem with Er:YAG laser technology is that the
hydroxy silica quartz fibers used in Ho:YAG
machines are not compatible.
 Sapphire fibers used with Er:YAG are too brittle and
thick to be used in routine endourologic procedures.
Laser Lithotripsy
Chennai
44

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 For flexible ureteroscopy, the fiber must be durable
enough to repeatedly pass through scope without
breaking even when deflected to 270 degrees.
 Ho:YAG laser lithotripsy fulfills these requirements
because hydroxy silica fibers are thin, flexible, and
durable.
Laser Lithotripsy
Chennai
45

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 Flexible ureteroscopy typically uses 200-μm laser
fibers, which have a minimal impact on scope
deflection.
 For semirigid ureteroscopy, 365-μm fibers are more
suitable, although they can be used with flexible
nephroscopy if minimal deflection is required.
 Fiber advancement should be performed with the
scope tip in neutral position and then actively
deflected to the area of interest.
Laser Lithotripsy
Chennai
46

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 Newer fibers (i.e., Flexiva TracTip [Boston Scientific,
Marlborough, MA]) have been created with a carved
bulbous tip, theoretically allowing the fiber to pass
through an already deflected scope without damage.
 With low energy and high frequency small debris are
created. This technique is known as “Painting”
 “Popcorning” uses both the photoacoustic and the
photothermal mechanisms of laser lithotripsy.
 Pop corning requires shorter pulse duration.
Laser Lithotripsy
Chennai
47

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 Although most Ho:YAG lasers have fixed durations
of 250 to 350 μm, adjustable units are becoming more
common.
 Shorter pulses yield higher peak power in resulting
shockwaves.
 The fiber tip is placed several millimeters away from
the stones (and mucosa), and shockwaves produced
by vapor bubbles collapsing cause stones to bounce
like popcorn.
Laser Lithotripsy
Chennai
48

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 As time passes, the “popcorning” effect continues to
produce smaller and smaller fragments, resulting in
a fine stone dust, which is passed without
consequence.
 An in vitro experiment identified settings of 1.0 J and
20 Hz as giving the most efficient fragmentation
when using this technique.
Laser Lithotripsy
Chennai
49

Chennai
50

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Lasers in PCNL
 Anterograde nephroscopy using flexible scopes can
access calyces that rigid nephroscopes cannot reach,
reducing the need for multiple accesses.
 Laser fragmentation is central to percutaneous
nephrolithotomy performed with reduced-diameter
sheaths (i.e., minipercutaneous, ultra-
minipercutaneous, micro percutaneous).
Chennai
51

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 This combines ultrasonic and pneumatic lithotripters
into a single hand piece.
 Pneumatic lithotripsy is effective at fragmenting
harder stones, whereas ultrasonic action produces
smaller fragments, while simultaneously removing
them from the field.
 Ex. Swiss LithoClast Ultra and CyberWand
Dual Modality
Lithotripters
Chennai
52

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 The front piece houses the ultrasonic lithotripter,
with a central channel allowing throughway for the
slender pneumatic probe.
LithoClast Ultra
Chennai
53

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 For maximal control, the tip of the pneumatic probe
should be slightly recessed from the outer ultrasonic
probe.
 In this way, the ultrasonic probe can make maximal
contact with the stone surface, and pneumatic
retropulsion is limited.
 When activated, the pneumatic tip advances and strikes
the stone beyond the ultrasonic probe tip.
 If large immobile stones are being treated (i.e., staghorn
calculi), better fragmentation can be achieved by
adjusting the pneumatic probe 2.5 mm past the ultrasonic
sheath;
Chennai
54

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 In this system hand piece has pizo electric crystal
which produces vibrational energy.
 Disposable probes are made up of inner 2.77 mm
and outer 3.75 mm cylindrical metal tube.
 Selecting Large stone setting on the foot pedal
couples both sheath. Ultrasonic energy from inner
sheath is transmitted to outer sheath and outer
sheath moves in ballistic manner similar to
Pneumatic Lithotripter.
Cyberwand
Chennai
55

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 The Small stone setting activates only the ultrasound
action of inner probe.
 Several studies showed the combination of
pneumatic and ultrasonic lithotripters is more
efficient compared with pneumatic or ultrasonic
lithotripsy alone.
Cyberwand
Chennai
56

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