Veterinary HFR

What is electrosurgery?

Electrosurgery is the use of electrical energy in the form of radio waves in the High Frequency radio band applied directly to tissue to induce histological effects. Like laser treatment, electrosurgery is thermo-dynamic and develops heat directly within tissue cells. Unlike laser however, electrosurgery works over the entire surface of the electrode tip in contact with tissue, which makes it ideal for sculpting living tissue.

Where is electrosurgery used?

Electrosurgery is used on soft tissue. In general surgery, electrosurgery is used on nearly every soft tissue in the human body. The energy introduced by electrosurgery reacts with water molecules within the cells of the tissue being treated.

Why use electrosurgery in veterinary practice?

The primary rationale for electrosurgery is because it allows surgery with concurrent hemostasis to be performed. In addition it performs coagulation in order to control bleeding or to desiccate diseased tissue (ablation). It may also be used to seal vessels.

Common uses of electrosurgery are: General surgery, emergency care, neuter, dental, oral, de-claw, de-bark, ear crop, tail dock, eyelid surgery, eyelid epilation, treating dermal lesions, biopsy, and to control bleeding in hemolytic compromise.

Is anesthesia required?

Yes, anesthesia is required for electrosurgery.


How is electrosurgery applied?

By means of two electrical connections called “electrodes”.

In “monopolar” electrosurgery, one is an “active” electrode and is used to introduce therapeutic current into tissue. These are also called “tips” or “electrode tips” and come in a wide variety of sizes and shapes suited to specific clinical indications for incision, excision, curettage, and coagulation. These are held in an insulated hand piece. The other electrode is the “dispersive” electrode and is in the form of a large flexible pad. The “Dispersive” connection to the patient is by means of capacitive coupling which can work through the patient’s coat without direct skin contact so that the patient reclines against the dispersive pad (or “plate”) completing the electrical circuit.

In “bipolar” electrosurgery, both electrodes are the same or similar size and are mounted on a common hand piece. No separate dispersive plate or pad is used and the cable from the bipolar hand piece to the electrosurgery unit has two conductors.

“Bipolar” refers to two things, a situation which engenders some confusion. First, it refers to a technique where therapeutic current is restrained to the immediate volume of tissue being treated and does not diffuse through the body. Bipolar electrodes are exemplified by bipolar forceps, where the two tips of the forceps are insulated from each other, and two wires connect the forceps to the unit. Bipolar also refers to the electrosurgical unit itself in terms of RF isolation. “Bipolar” is defined as a greater degree of isolation than “isolated”.  Delmarva HFR isolated units are rated safe for bipolar coagulation but not for incision or excision. Bipolar accessories are certainly not safe with ground referenced generators.

What is “isolated output”?

It refers to the path therapeutic current takes from the active electrode back to the unit. In an isolated output unit the path is from the active electrode, through the body, through the dispersive electrode and back to the unit. A very small clinically negligible amount of therapeutic current can stray off to electrical earth ground. The limitation of stray, or “RF leakage” current, prevents alternate site burns and makes isolated output units safe for concurrent use with physio-monitoring equipment and significantly reduces radio interference with other equipment in the room. This has been the standard in general surgery operating rooms for over 25 years. Isolated output units absolutely will not work without a dispersive plate in monopolar application. Therapeutic current in “ground referenced” units returns to the unit primarily through the dispersive electrode, which is connected to electrical earth ground through a capacitor inside the unit. However, therapeutic current will flow through any electrical path to earth ground wherever it is available: capacitively through the chair or table, through physio-monitoring leads such as EKG leads, or wherever else the patient contacts earth ground. These units can work without a dispersive plate when sufficient capacitive coupling between the patient and the chair or table exists. These units do readily interfere with other electronic equipment and are not recommended for use in conjunction with physio-monitors or with bipolar accessories. It is also not advisable to touch the metal casing of these units during operation either, since there is a risk of an unpleasant tingling or “shocking” sensation and even a small risk of coagulation burn.

Is electrosurgery safe around pregnant patients or veterinary physicians?

Yes. Safety is enhanced with isolated output units since therapeutic current does not diffuse through the body into the table; rather, it is significantly constrained to the dispersive pad. Judicious placement of the dispersive pad will prevent electrosurgical therapeutic current from passing through the womb. Do avoid draping the cables over the patient, especially the abdomen, for the greatest safety.

Is electrosurgery “self sterilizing”?

No. Bacterium and fungi are volatized along with target tissue and viruses can survive electrosurgery as well as in laser or thermal cautery interventions. Autoclaving the electrodes and hand piece before use is absolutely required in order to avoid cross contamination.

What is “fulguration”?

Fulguration is the application of electrosurgical therapeutic current by means of an arc, or spark. Commonly used in dermatology and general surgery for bleeding control over large areas, the effect of the technique is somewhat superficial and does not go deep into tissue. The treatment area is desiccated to about 1mm depth with an underlying coagulum. There may appear some eschar on the surface. This arcing represents a column of ionized atmospheric gases and limits the flow of therapeutic current while spreading it out over an area under the electrode. High voltage is required for effective fulguration.

What are the advantages of a 4.0MHz electrosurgery unit over lower frequency ones?

Assuming operating frequency is high enough (over 100KHz); neuro-muscular stimulation is avoided. A higher frequency of 4.0MHz provides better efficiency for the non-direct contact capacitive dispersive pad in comparison to most general surgery units which typically run around 500KHz or less and which rely on direct contact dispersive pads.

What about smoke and odor?

This phenomenon is shared by laser and thermal cautery, arising from the volatization of cellular fluid contents, primarily during incision and excision. The use of high speed suction held near the surgical site or a dedicated smoke evacuator is recommended, both of which are effective. Judicious use of irrigation can also help to reduce smoke production.