Page 27 - World Journal of Laparoscopic Surgery

WJOLS

Perspective of Electrosurgical Sources in Minimal Access Surgery
But the electrosurgical device does not give us the occurs. Monopolar electrosurgery generates tissue tem-
privilege to set the current on our own. They allow us peratures of ~100°C, 100–200°C, and >200°C for desicca-
to set the power (W) for application. The relationship tion, vaporization, and fulguration respectively. Other
of power to above variables is product of voltage and laparoscopic energy sources have limited tissue effects of
current. desiccation and coaptation, and they also generate tissue
temperatures of ~100°C. 1,4
W = V × I
The major disadvantage of monopolar electrosurgery
For example, as the current flows through the target is the unavoidable risk of stray current injury (SCI). These
tissue and coagulates it, the tissue becomes nonconductive injuries are regularly not seen amid of surgery as they
and current takes the path of least resistance. Hence, the ordinarily happen outside of the specialist’s field of vision.
path of current in living tissue is erratic. They are not attributable to specialist mistake or absence
Broadly, there are two types of electrosurgery of ability. Rather, it is the physics at fault. When used in
resources available: Monopolar and bipolar energy contact mode, there is the risk of lateral thermal spread
sources. injury to adjacent structures with monopolar electro-
surgery, just as for all energy sources that yield tissue
MONOPOLAR ENERGY
effects of desiccation and coaptation. Smoke production
All electrosurgery is “bipolar” in light of the fact that the during monopolar electrosurgery may be problematic,
electrical current streams from one electrode on to the especially during fulguration. 3
other. In monopolar electrosurgery, the active terminal There is a risk of capacitative coupling if by mistake
is one electrode in surgeon’s hand and the patient return the wire gets wrapped around other instrument. So,
cathode is the other. The primary contrast between monopolar electrosurgery is a relatively inexpensive,
monopolar electrosurgery and the other electrosurgery readily available, and versatile energy source that yields
modalities is that electrical current courses through the the best range of tissue effects, but despite all this it has
patient. This distinction benefits the best scope of tissue a large risk of complications leading to smaller safety
impacts to monopolar electrosurgery. 1,2 margin.
The tissue impacts produced with monopolar electro-
surgery incorporate vaporization (tissue destruction and PRINCIPLES OF MONOPOLAR
cutting), fulguration (tissue destruction and little vessel ELECTROSURGERY
hemostasis), desiccation (cell wall break and cytoplasm
boiling), and coaptation (vessel sealing inferable from Current Pathway
2
denaturation and renaturation of proteins) (Table 1). In monopolar electrosurgery, electrical current goes from
These tissue impacts are fundamentally accomplished the ESU to the active electrode, then via the patient to
by using the “cut” or “coag” mode of electrosurgical unit exit by means of a dispersive electrode, at last coming to
(ESU) while contacting or non contacting the objective “electrical ground” (Fig. 1). The potential for SCI emerges
3
tissue (Table 2). Varying other parameters are under the in light of the fact that power inside the patient will take
specialist’s control, such as power setting, length of enact- whatever pathway it can to come back to ground, includ-
ment, and terminal arrangement, can facilitate adjusting ing by means of unintended tissue targets. 1-7
the wanted tissue effect. 1-3
All energy sources generate tissue temperatures above Current Density
45°C, the temperature at which irreversible cell damage
The tissue impacts of monopolar current are identified
with the current density in the tissue. Consequently,
Table 1: The main classes of laparoscopic energy sources
and their tissue effects 2 engaged current from the active electrode enters the
patient at the site of surgery to yield a tissue impact
Energy source Tissue effects
Monopolar electrosurgery Vaporization, fulguration, though current, leaving the patient by means of a disper-
desiccation, coaptation* sive return electrode just results in a clinically inconse-
Conventional bipolar Desiccation, coaptation quential ascent in tissue temperature due to low current
electrosurgery density. Any damage can happen at any part of the circuit
Advanced bipolar Desiccation, coaptation, blade in the event where the current density is sufficiently
electrosurgery** tissue transection
Ultrasonic technology Desiccation, coaptation, high. For case, blazes have beforehand happened at the
mechanical tissue transection patient return electrode inferable from poor contact with
*Vessel sealing achieved with coagulation and compression. the patient's skin, leading to high current density at the
**Tissue impedance monitoring optimizes activation time. current way out point.
World Journal of Laparoscopic Surgery, September-December 2016;9(3):130-137 131