Electrocoagulation
Electrocoagulation is used to cause deeper tissue destruction and to stop bleeding with minimal carbonisation. The haemostatic and destructive capacity of electrocoagulation makes it ideal for the treatment of skin cancers and vascular skin conditions such as pyogenic granuloma. It can also be used to stop small blood vessels from bleeding during skin surgery.
Electrocoagulation uses monopolar or bipolar electrodes to produce low voltage and high-amperage current at relatively low power. An indifferent electrode prevents accumulation of current in the patient, hence low voltage is sufficient to establish current flow. High amperage causes deep tissue destruction and haemostasis by fusion of blood vessel collagen and elastic fibres.
The electrode is applied across the lesion until slightly pink to pale coagulation occurs. Coagulated tissue has greater resistance to electrical current than normal skin, and limits the amount of damage.
Electrocoagulation may result in permanent scarring and white marks (hypopigmentation).
Freestar
Electrosection
Electrosection is used to simultaneously cut skin and seal bleeding vessels by blending damped and undamped wavetrains. It is suited for excision of large, relatively vascular lesions, such as benign dermal naevi (moles), skin tags, or for shaving off seborrhoeic keratoses, folliculitis keloidalis nuchae and rhinophyma (see rosacea). Electrosection requires almost no manual pressure from the operator as the electrode glides through tissue with minimal resistance.
Electrosection uses an monopolar electrode to produce low-voltage and high-amperage current at higher power than is used for electrocoagulation. The current is highly focused to vaporise tissue with minimal peripheral heat damage. The electrode is usually a fine tungsten wire or loop.
The destruction of chemical bonds or decomposition of tissue arises through thermolysis (heat-induced) and electrolysis (via DC electric-current). The main component of tissue is water, which is broken down into its components, hydrogen and oxygen.
Radiofrequency devices are often used for electrosection, e.g. Ellman Surgitron®. They produce little heat so cause little collateral tissue damage.
An assortment of single use or disposable electrodes are available for the Surgitron.
Needles are available in various lengths and diameters.
Shaft may be straight, at an angle or curved.
Cutting wire, round, triangle or diamond-shaped loops come in various diameters and wire size.
Ball tips of various size can be used for coagulation.
Blade ‘scalpel’ electrodes
Insulated, coated needles can be used for sclerotherapy or internal sites.
Special handpieces can be used for nonablative skin tightening (radiothermoplasty).
Compared with surgical removal, benefits of electrosection include reduced surgical time, reduced post-operative complications (pain, swelling, infection), maximum readability of histologic specimen, enhanced healing and excellent cosmetic results. No sutures are necessary when it is used to remove small skin lesions flush with the normal skin contour.
Thermocautery
Thermocautery is used for pinpoint haemostasis during surgical procedures or to get rid of small blood vessels (telangiectasias).
Direct electric current is used to heat the surgical element, which then causes thermal injury by direct heat transference to the tissue. In contrast, in electrosurgery, the treating electrode remains cold.
Portable and disposable thermocautery devices are available powered by penlight batteries. The Shaw Hemostatix® Scalpel is a form of thermocautery in which a heated disposable copper alloy blade is used to cut tissue with reduced bleeding in highly vascular areas.
Thermocautery is suitable for patients with an implanted pacemaker or defibrillator.
Risks of electrosurgery
The risks of electrosurgery include electric shock and electrical burns, thermal burns, transmission of infection and production of toxic gases.
Electric shock
Electric shock can be minimised by:
Use of earthing/indifferent electrode
Surgeon wearing plastic surgical gloves
Electric/thermal burns
Electric/thermal burns can be minimised by:
Use of non-flammable cleanser such as chlorhexidine or povidone-iodine
Ensuring indifferent electrode has broad contact with skin and is not placed over a bony prominence, scar tissue, or implanted metal
Ensuring patient is not in contact with grounded metal objects
Removal of eschar: this is a fire hazard as it can ignite.
Transmission of infection and production of toxic gases
Electrosurgery may be used to treat viral warts. Thermolysis will generate smoke/fumes which may contain human papillomavirus (HPV) particles that may be transmitted to the operator who breaths in or comes into contact with the fume. When working with HPV-related lesions, minimise the risk of transmission.
Use smoke evacuator with intake nozzle 2 cm from operative site
Wear surgical mask (N95 is most effective) and eye protection.
Other viral DNA, bacteria, carcinogens, and irritants are also known to be present in electrosurgical smoke. NIOSH (the National Institute of Occupational Safety and Health) a division of CDC (Center for Disease Control, USA) have also studied electrosurgical smoke at length. They state: “Research studies have confirmed that this smoke plume can contain toxic gases and vapors such as benzene, hydrogen cyanide, and formaldehyde, bioaerosols, dead and live cellular material (including blood fragments), and viruses.”
Smoke can be removed using hand held suction. Newer smoke evacuation devices can be attached directly to a standard electrosurgical pencil reducing the work of an assistant during surgery.
Cardiac pacemaker and defibrillators
Electric currents from electrosurgery electrodes pass through the patient's body to the indifferent electrode. This may sometimes cause malfunction of implanted cardiac devices.
This risk may be mitigated in the following ways.
Use thermocautery including Shaw scalpel (no current flow through patient)
Use bipolar forceps with electrosurgery device (minimises current through patient)
If possible, avoid operating near the implanted device
Change pacemaker to fixed-rate mode or magnetically deactivate implantable cardioverter-defibrillator during electrosurgery.
Pre and postoperative input from a cardiologist may be required in complex patients.