Flashcards in Electrosurgery, electrocoagulation, electrofulguration, electrodessication, electrosection, electrocautery Deck (89):
Electrosurgery refers to hermal tissue damage resulting from tissue resistance to the passage of high-frequency, alternating electric current.
Electrocautery is a form of electrosurgery.
F No current flows through the patient.
Electrocoagulation, electrofulguration, electrodesiccation and electrosection are not forms of electrosurgery.
The precise tissue effect of electric current depends on current density, voltage and electromagnetic waveform.
The risk of pacemaker and implantable cardioverter-debfibrillator malfunction with electrosurgery is high.
F Extremely low.
Electrolysis uses direct current to induce tissue damage via a chemical reaction at the electrode tip.
Coblation uses high-frequency alternating current to ionize an electrically conductive medium (usually isotonic saline solution) and transmits heat to cause superficial epidermal and dermal damage with minimal collateral tissue destruction.
T It’s used for facial rejuvenation.
Electrocautery uses tissue resistance to the passage of high-frequency alternating current to convert electric energy to heat, resulting in thermal tissue damage.
F This is true for high-frequency electosurgery, ie. electrodessication, electrogfulguration, electrocoagulation, electrosection.
Electrosection uses direct or high-frequency alternating current to heat an element that causes thermal injury by direct heat transference to tissue.
F This is true for electrocautery.
The element in electrocautery is hot, unlike the cold electrode of electrosurgery.
Electric current refers to the net flow of electrons through a conductor per second, and is measured in amperes.
The thinner the electrosurgical tip, the lower the current density at the point of electrode contact.
F Thinner tip = greater current density.
High current density results in greater tissue injury, and is the basis of surgical diathermy.
Therapeutic uses of direct current include electrolysis, iontophoresis, and sometimes electrocautery.
Resistance refers to the ability of a conductor to impede the passage of an electric current, and is measured in ohms.
Fat has a low resistivity to electric current, whereas muscle has a high resistivity.
F Fat = high resistivity, muscle = low
The resistivity of wet skin is higher than the resistivity of dry skin.
F Wet = low, dry = high
Electric current always flows from a region of high electron concentration to one of low electron concentration.
Heat production in tissue depends on such factors as resistance, current density and the duration of current application.
For a given current density, heat production is greater in fat than muscle.
T Because of its higher resistivity.
Minimal heat is generated in substances with high resistance.
F Little resistance. Eg blood
An electrosurgical unit is composed of three components: a transformer that modifies voltage; an oscillating circuit that increases the frequency; and the patient circuit.
Undamped waveforms are used in electrosection.
Moderately damped waveforms are used in electrofulgaration.
Markedly damped waveforms are used in electrocoagulation and electrodessication.
F Electrofulguration and electrodessication.
Cardiac pacemakers, deep-brain stimulators or implantable cardiodefibrillators may malfunction in the presence of electromagnetic radiation.
A non-alcohol solution such as chlorhexidine or povidone-iodine should be used when performing electrosurgery.
T Alcohol may spark or heat.
When performing electrosurgery in the perianal region, moist packing should be placed over the anus to prevent ignition of methane.
The prefixes ‘mono-‘ and ‘bi-‘ refer to the number of treatment electrodes used in electrosurgery. .
T Mono = 1 electrode delivers current to pt. Bi = 2 electrodes
Electrodessication and electrofulguration involve deep tissue destruction.
F Superficial. Electrocoagulation is deep.
Electrofulgration and electrodessication are monoterminal.
Electrocoagulation and electrosection are biterminal.
Electrocautery is monoterminal.
F No terminal – hot wire.
Electrofulguration involves tissue contact with an active electrode.
Electrodesiccation, electrocoagulation and electrosection do not involve tissue contact with an active electrode.
Voltage used for electrocagulation, electrosection and electrocautery is high.
F Low. Amperage is high.
Voltage used for electrofulguration and electrodessication is low.
F High. Amperage is low.
At low power settings electrofulguration and electrodessication are the preferred method for superficial lesion destruction
Treatment of highly vascular lesions with electrofulguration and electrodessication may result in a wet operative field, which quickly dissipates the heat
Because of their low amperage, electrodesiccation and electrofulguration are best suited for destruction of superficial and relatively avascular lesion, such as verrucae and seb K
Most tissue damage performed with electrofulguration and electrodessication is epidermal and there is minimal risk of scarring with lower power settings. .
T Higher power settings may be assoc with increased dermal coagulation, superficial scarring and hypopigmentation
Electrodessication represents a variation of electrofulguration in which the electrode is held 1-2mm fro the skin surface, and causes superficial tissue dehydration by sparks.
F Other way around. Electrofulgration is the variant of electrodessication.
Electrodessication and electrofulguration are best suited for superficial and relatively avascular lesions, such as verrucae and seborrhoeic keratoses.
Electrocoagulation uses low-voltage, moderately damped or partially rectified, high-amperage current in a biterminal fashion to cause deeper tissue destruction and haemostasis with minimal carbonisation.
The heat generated with electrocoagulation can be used to seal vessels by fusion of their collagen and elastin fibres.
T Operative field must be dry for maximal efficacy.
Electrocoagulation with biterminal forceps offers the advantage of localised electrocoagulation with minimal current flow beyond the treatment area.
Electrosection with undamped current yields cutting with some coagulation, whereas slightly damped current yields cutting without coagulation.
F Undamped = without coagulation,
Slightly damped = some coagulation
Electrosection using pure sine waves provides benefit over conventional scalpel surgery.
F Pure sine waves cut without coagulating.
Electrosection currents are commonly ‘blend’ damped and undamped wavetrains to cause simultaneous cutting and coagulation.
When performed correctly, electrosection requires moderate manual pressure from the operator as the electrode glides through tissue.
F No manual pressure as electrode guides through tissue with minimal resistance.
If sparking occurs during electrosection, the power setting is likely too high.
If the electrode drags during electrosection, the power setting is likely too low.
Advantages of electrosection are its speed and its ability to simultaneously cut and seal bleeding vessels.
Electrocautery uses low –voltage, high-amperage, direct or alternating current to heat a surgical tip to cause tissue dessication, coagulation or necrosis by direct heat transference to the tissue.
Carbonised tissue on the treatment electrode decreases current density and insulates against current flow, thereby reducing cutting and coagulation effect.
C+C actually refers to the sequence of curettage followed by electrodessication applied in 2-3 repetitions to the lesion.
If one reaches subcutaneous fat during C+C the procedure should be abandoned for excision.
C+C should be used with caution in lesions with the potential for follicular extension as recurrence risk is higher.
C+C should only be used to treat superficial BCC.
F Also nodular.
The highest cure rates for BCC treated by C+C destroy a substantial peripheral margin around the initial curettage.
Cure rates for BCC treatment with C+C vary from 60-70%
Patient age, sex, and lesion duration before treatment of a BCC with C+C are significant determinants of 5-year recurrence.
Increasing lesion diameter is not a significant determinant of 5-year recurrence post treatment of a BCC with C+C
Anatomical location is an independent determinant of 5-year recurrence post BCC treatment with C+C
T High risk sites = nose, paranasal, NLF, ear, chin, mandible, periocular, perioral
Low-risk sites for BCC recurrence post C+C include the scalp, forehead, pre- and post-auricular and malar areas.
F These are middle-risk sites. Low-risk = neck, trunk, extremities.
BCC 5-year recurrence rates post C+C are 3% for low-risk sites, 5% for middle-risk sites for lesions 10mm) and 5% for high-risk sites for lesions 5 mm).
Haemostasis can be performed on vessels up to 4mm.
F 1mm. Bigger should be ligated.
Incisions can be safely made with electrocoagulation.
F Associated with higher postop infections.
Electrosection results in more collateral tissue damage compared to scalpel surgery with some histological distortion of surgical margins.
For specimens requiring H&E analysis, use of a filtered, fully rectified current (cutting without coagulation) should be used to prevent significant electrosurgical artefact.
Electrochemotherapy refers to the local application of short, high-voltage, electric pulses to tumour tissue to increase tumour uptake of local or systemic chemotherapy.
Wounds created by electrosection develop tensile strength more rapidly than scalpel wounds.
F They are weaker for 21 days postoperatively, and thereafter have equal strength.
The indifferent electrode should have broad contact with skin, and not be placed over a bony prominence, scar tissue, or implanted metal.
With pacemakers/defibrillators, they may be changed to a fixed-mode rate or magnetically deactivated during electrosurgery to prevent malfunction.
Intraoperative techniques to minimise pacemaker/debfibrillator malfunction include using electrocautery, Shaw scalpel (no current flow through patient), or biterminal forceps (minimises current leakage in patient).
When performing electrosurgery on a patient with a cardiac PPM or defibrillator, you should choose a site far from the heart and device for grounding.
When performing electrosurgery on a patient with a cardiac PPM or defibrillator, you should ensure that the heart does not lie directly in the path between the treatment and indifferent electrode.
When performing electrosurgery on a patient with a cardiac PPM or defibrillator, the duration of electrosurgical current does not need to be restrained.
F Use current bursts
Current ‘channelling’ refers to the phenomenon of current concentration as it flows through a small area.
Current ‘channelling’ particularly occurs on vascular areas.
F Areas with narrow stalk or base.
Current ‘channelling’ has been reported on the scrotum with subsequent necrosis.
The active electrode of an electrosurgical device may be left on the patient while not in use.
F Should never do this due to risk of burn from inadvertent activation.
An indifferent electrode can be cut to size or bent in order to conform to the patient’s anatomy and allow for better contact.
F Never do this – decreases the dispersion area, current may concentrate at points.
The risk of current channelling may be minimised by using ‘bipolar’ forceps, an indifferent electrode, or by increasing the cross-sectional area of current flow.
T Wrap saline-soaked sponge (electrolyte conductor) around narrow base of mass being treated.
The heat induced by electrosurgery sterilises the electrode tip.
F This is true for electrocautery.
HPV may become aerosolized in blood microdroplets and in electrosurgical smoke.
Demand-type pacemakers are not affected by electrosurgical interference, whereas fixed-rate pacemakers can be.
F Other way round.
Electrosection poses the greatest risk for PPM-related complications.