Electrosurgery and its Equipment
In 1926, an electrosurgical generator was first used at Brigham Hospital in Boston to remove a portion of tumor, it enabled a surgeon to remove a portion of tumor that couldn’t be taken out using more traditional methods, and with almost no bleeding.
The following are advancements that have been made since the introduction of the procedure:
Uses of Electrosurgery :
An Electrosurgical Unit is the application of a high-frequency electric current to biological tissue as a means to cut, coagulate, desiccate, or fulgurate tissue.
An ESU can be used to remove warts, spider veins or hair in the doctor’s office, as well as for heart, orthopedic or transplant procedures in the operating room. The cutting or coagulating effects on tissue is achieved using alternating currents at a high frequency.
Monopolar vs. Bipolar:
Electrosurgical applications may be monopolar or bipolar. In monopolar electrosurgery, tissue is cut and coagulated by completing an electrical circuit consisting of a high-frequency oscillator, amplifiers, the patient plate, connecting cables and the electrodes. Generally, the electric current runs through the surgical site with an active cable and electrode. The current then disperses through the patient to a return electrode. The energy returns to the generator, completing the circuit.
In bipolar electrosurgery, two electrodes are used – a patient plate isn’t necessary. The electrosurgical current in the patient is restricted to a small area of tissue, allowing the doctor greater control over the area to be coagulated.
Electrosurgery revolves around an extremely concentrated radio frequency current used to induce heat energy. This energy, in turn, can dry out tissue cells (resulting in the coagulation of blood) or vaporize cells (permitting an electrode to physically separate a path through living tissue). In electrosurgery, all of the current is forced to flow through a tiny area where the active electrode makes skin contact.
A generator can deliver its current via discrete or nondiscrete output. Discrete output means that although several active instruments are attached to the ESU, only one accessory can be activated at once. With nondiscrete output, when one accessory is activated, any of the other accessories connected to the unit are also activated. The physician must be careful to isolate all additional accessories from the operation site.
An ESU offers two types of cutting: pure cut and blended cut. Pure cut is intended for dissection – the electrosurgical effect of tissue dehydration and protein denaturation caused by direct contact between the electrosurgical electrode and tissue. Desiccation involves a lower current density and concentration than cutting.
In pure cut, the instrument performs similarly to a stainless steel scalpel, where the surgeon has little control over bleeding. However, it is the current that parts the tissue, not a scalpel. An active electrode encounters little resistance as it passes through tissue, making cutting nearly effortless. Much less pressure must be applied here compared with handling a scalpel, and the surgeon can focus on guiding the instrument.
A blended cut enables the doctor to cut and coagulate simultaneously. While in a pure cut the heat energy is so intense that cells vaporize, in blended cutting cooling periods decelerate the process to a slow dehydration of cellular fluid and protein. This stops the bleeding as the cuts are being made. Various levels of hemostasis can be achieved by adjusting the cutting blend. Typically, an office unit has one or two blend modes, and an operating room unit has between two and four blend modes. Once in a while, a unit offers more blend modes – as does the Aaron 2100 (Aaron Medical), which offers nine modes – but that is unusual.
Equally important to the cutting method is the coagulation process. The two types of coagulation – pinpoint and fulguration (spray) – differ in terms of how they are applied. With pinpoint, the doctor holds the electrode in physical contact with the tissue. When fulgurating, the electrode doesn’t touch the tissue. Instead, the current is delivered via sparks that contact the tissue. Pinpoint coagulation is used to stop local bleeding, while fulguration is useful for sealing off small, hidden bleeders or larger bleeders.
High Frequency Desiccators:
Today, surgeons have access to accurate, user-friendly instruments – low-powered electrosurgical devices without cutting power designed for dermatological work. These units are not to be confused with a cautery, which uses heat to perform a task. A high frequency desiccator relies on a specific waveform to desiccate, fulgurate or coagulate. Coagulation may be achieved using either a monopolar hand piece or in bipolar mode. In addition, high frequency desiccators don’t require the physician to use a grounding pad.
Units currently available are the Aaron 800 and 900 models (Aaron Medical) and the Hyfrecator (CONMED Corp., Utica, N.Y.). All three units are used in the same way, although they tout different features. Generally, procedures performed using high frequency desiccators are completed at a power setting under five watts. All three of these units are said to be accurate at low power settings.