PRIMENA RADIOTALASA U ORALNOJ HIRURGIJI THE USE OF RADIOFREQUENCY ABLATION IN ORAL SURGERY

Uvod: Aparati koji koriste elektromagnetno zračenje u vidu visokofrekventnih radiotalasa sve češće nalaze primenu u mnogim granama medicine, a u poslednje vreme i u oralnoj hirurgiji. Rade na istom principu kao i elektrokauteri, s tom razlikom što elektrokauteri koriste talase frekvencije od 300kHz do 500kH, a radiotalasni aparati talase frekvencije 4MHz. To im omogućava daleko manju dubinu prodiranja energije, manju destrukciju i ograničeno lateralno oštećenje tkiva, bez opekotinskog efekta. Zarastanje rana je brže, formiranje ožiljaka je manje, a kozmetički efekat je izraženiji. U toku godinu dana na Odeljenju za oralnu hirurgiju primenjivanje radiotalasni aparat kod mnogih oralnohirurških intervencija. Sečenje tkiva bez dodira, simultano, sa izrazitim hemostatskim efektom ili čista koagulacija sprovode se vrlo jednostavno i uspešno. Aparat je testiran prilikom rada na mekim tkivima kože i sluzokože. Pravilnim i stručnim rukovanjem izbegavaju se eventualni štetni efekti. Kod pacijenata sa srčanim pejsmejkerom treba biti posebno obazriv i pridržavati se protokola. Ukoliko pacijent ima ugrađene dentalne implantate kontraindikovano je njihovo dodirivanje u toku rada aktivnom elektrodom. Zaključak: Radiotalasna hirurgija ima niz prednosti u odnosu na konvencionalnu hirurgiju u određenim indikacionim područjima.


Introduction
The application of heat in order to stop the bleeding is known from the Neolithic period. Ancient Egyptians (3000 BC) described the use of metal instruments for the treatment of the ulcers and breast tumor. Hippocrates (469-370 BC) used the heat to remove the tumor from the neck. The Ancient Romans, had already warmed the various metal instruments for the control of bleeding 1 Hot oil, and even gunpowder (combustion in tissue), found in China in the 13th century were used for similar purposes throughout history. In the mid-eighteen century, with the appearance of electricity, for the first time its use for heating instruments to perform coagulation was described 2 . The thermocauteries were developed soon; their working part made of wire was heated to candescence and used to stop the bleeding. Thermocauteries are widely used today, especially in dentistry and are integral part of most dental devices. The discovery of alternating currents quickly affected the development of electrosurgery. One of the most important parameters of alternating power is the frequency. It indicates the number of power changes in one second. It was discovered that alternating current frequencies, by moving through the human body, cause muscle contraction, while alternating high frequency current does not cause muscle contraction, but tissue warming. Thus, the diathermia (Greek: Through, Therme -heat) was rapidly developed; it was based on increasing the heat of a particular part of the body due to the resistance of the tissues to the high-frequency power pass. When the high frequency flows over a large surface the effect of warming tissue is small and remains within the physiological range (40-45°C). These appliances have been used in physical medicine. However, when the density of high frequency electricity is concentrated on small dotted surfaces, the heating effect is large (250 -600°C), which enables cutting and coagulation of tissues. These appliances have been used in surgery. William T. Bovie 1920. constructed the first electrosurgical appliance 3 . Since then, electrosurgery has been rapidly evolving and is now represented in most surgical institutions.
Radio waves are a kind of electromagnetic radiation. They are part of an electromagnetic spectrum immediately above infrared radiation, wavelengths of 0.3 to a few kilometers, frequencies from 3Hz to 300GHz. They are obtained using the alternating power generator.
Za razliku od elektrokautera radiotalasni aparati koriste radiotalase frekvencije od 4MHz. Pri njihovom radu elektromagnetna energija u kontaktu sa tkivom ne pretvara se u toplotnu energiju,već se toplota generiše u samom tkivu, tj. apsorbuje u vodenoj komponenti ćelije izazivajući njeno isparavanje 7 . Aktivna elektroda ne mora da ostvari prisan odnos sa tkivom (radi se simultano), jer funkcioniše kao antena, a ne kao elektroda 8 . Ona ostaje hladna, nema dima ili ga ima vrlo malo. Može biti različitog oblika (igla, kuglica, pločica, omča). Krvni sudovi apsorbuju ćelijsku plazmu, tako da nema ostataka nekrotičnog tkiva. Dubina prodiranja energije radiotalasa iznosi manje od 0,02 mm, što prouzrokuje manju traumu ćelija, minimalno lateralno oštećenje tkiva bez opekotina, brže zarastanje rana i formiranje manjih ožiljaka 9 . Savremeni radiotalasni aparati imaju veći broj različitih talasnih oblika sa različitim efektom dejstva na tkiva. U toku rada pasivna elektroda ne zahteva direktan kontakt sa pacijentovom kožom. Može da deluje i preko tanke tkanine (pantalone, suknja) tako da je dovoljno da Standard appliances for electro-cauterization use radio waves frequency of 300kHz to 500kHz 4 . Electrocauteries consist of two electrodes, a cathode and an anode, one of it is passive and is brought into contact with the surface of the body, while the other is active and the surgeon is holding it in his hand which he moves. During the contact of the active electrode with the tissue, an electric circuit is established, whereby electromagnetic energy is converted into heat energy that achieves coagulation and tissue cutting. So the thermal effect is present only around the active electrode, where the density of the current is greatest. It can be of different shapes. Thin sharp active electrodes create a high density current and therefore a high temperature. It is used to cut tissue. Active electrodes of large surfaces create currents of less density and therefore lower temperatures. They serve for coagulation. The current flows further through the tissue to the passive electrode, which has a much larger surface area, which reduces the density of the current and unwanted thermal effects are not present. The depth of penetration of thermal energy at the level of the active electrode is more than 1 mm 5 . This causes cell destruction, spreads lateral tissue damage, slower healing of the wounds and the formation of larger scars. During work, it is important to have a good direct contact of the passive electrode with the patient's skin. In addition, it attracts freed energy and returns it back to the appliance, which means that the best effect is achieved if the passive electrode is as close as possible to the operating region 6 . Application of conventional electrocautery appliances gives unequal and insufficiently controlled results. In addition, there is a risk of burns. In contrast to electrocautery, radio waves appliances use radio frequencies of 4MHz. In their work electromagnetic energy in contact with tissue does not turn into heat energy, but heat is generated in the tissue itself, i.e. is absorbed into the aqueous cell component causing it to evaporate 7 . The active electrode does not have to achieve a close relationship with the tissue (it works simultaneously) because it functions as an antenna rather than an electrode 8 . It stays cold, there is no or very little smoke. It can be of a different shape (needle, ball, tile, loop). Blood vessels absorb cell plasma, so there are no remains of necrotic tissue. The depth of penetration of radio waves of energy is less than 0.02 mm, causing a smaller cell trauma, minimal lateral damage to the tissue without burns, faster healing of the wound and the formation of smaller scars 9 .
Blend Cut (sečenje-koagulacija) -Monopolarni talasni oblik gde elektrohirurški generator proizvodi struju i napon nekontinuirano, sa prekidima. effects on the tissue. During the operation, the passive electrode does not require direct contact with the patient's skin. It can also work through thin fabrics (trousers, skirts) so that it is enough for the patient to sit or lean on the electrode. It is very important not to place a passive electrode near the heart (ventricular fibrillation). It should be placed closer to the surgical field 10 . The use of radio wave appliances provides predictable and controlled results, as well as great therapeutic safety. There is almost no risk of burns.
In the case of a radio wave appliances, as with electrocautery, tweezers coagulation method can be applied. The procedure consists of capturing the blood vessel with tweezers, and then the active electrode touches the tweezers and activates the apparatus. The tweezers then serve as an extension of the active electrode, and the coagulation takes place at the point of contact of the instrument and the blood vessel.
The applliance for radio wave surgery by dimensions is very similar to electrocautery. It often comes with a convenient and very useful stand, not heavy, easy to use and easily portable. It can be successfully used in surgical room and in oral surgery ambulance.
The authors used the radiosurgical appliance RWS 70 -PROXIMA medical technology, 70W power, 4MHz frequency, with foot control. The apparatus was used to cut and coagulate the tissues during the implementation of various oral surgical procedures on soft tissues over a period of one year. All surgical interventions were done at the Department of Oral Surgery at the Clinic for Dentistry at the Medical Faculty in Niš.
The radio appliance has three modes of work (pure cut, blend cut and soft coag), whose simple selection adjusts the character of the action at the level of the active electrode.
Pure Cut (cutting)-Monopolar wave form where the electro-surgical generator produces continuous current and voltage, without interruption. Cutting (evaporation, vapor-ization) is carried out by thin electrodes in the form of a needle or knife. The needle has a very small surface through which the high density current leaves the electrode and passes into the tissue. As the active electrode approaches the tissue, the air gap is shorter and, at one point, the spark from the electrode passes into the tissue in the form of a very narrow impact zone.
Za razliku od elektrokautera, koji daje veliki lateralni morbiditet rane, radiotalasna Due to the instantaneous heating of the liquid in the cells, the tissue evaporates the effect of cutting is appeared. This is done simultaneously so the tissue is nearly not touched by the active electrode.
Blend Cut (cutting-coagulation) is a monopolar waveform where electrosurgical generator creates electricity and voltage, discontinuously, with stops. The effect of coagulation depends on the duration of pause imported in the signal. Longer duration of the pause means larger effect of coagulation and vice versa. Ratio between the duration of the signal and pause inside the signal is displayed in percentage and it can be 75% and 50%.
If we were about to use larger mode for cutting tissue, it would require more voltage, which would cause bigger thermal lateral tissue damage.
Soft Coag (coagulation and coagulation spraying-non-contact phenomenon) is a monopolar waveform where electrosurgical generator creates electricity and voltage with most stops. Ratio between the duration of signal and duration of pause for contact coagulation is 50%, and for spraying coagulation (fulguration) goes up to 6%. As it has the longest duration of pause in signal for the same form of power, this type of mode requires very high voltage, thereby increasing the probability of adverse effects. It is performed by electrodes in shapes of smaller or larger globes. By touching the tissue, the area where the current leaves electrode is increased and transferred into the tissue. The density of electricity is decreased, which causes warming up of cellular fluids, dehydration and drainage of cells which still maintain their shape and form. Temperature goes from 70 to 80°C and white coagulum is formed. This means the coagulation is performed well. The active electrode has to be in sufficiently long contact (one second or half of second) with the tissue, for maintaining of effect of coagulation and dehydration. Further heating of the tissue causes carbonification of the tissue and the blood on the electrodes. Piled material on electrodes increases resistance, which increases voltage for maintaining the same source of power. Clean electrodes require lower voltage for transferring the same amount of power on tissue. Our experience shows that radiofrequency (radio wave) surgery is an alternative to conventional surgery in methods hirurgija izvanrednom preciznošću i minimalnim oštećenjem tkiva pruža veliku sigurnost naročito kada se radi u blizini osetljivih anatomskih struktura, kao što su nervi, krvni sudovi, estetske zone i sl.
As opposed to electrocautery, which gives large lateral morbidity to the wound, radio wave surgery with outstanding precision and minimal tissue damage brings greater security, especially when it is done near sensitive anatomical structures, like blood vessels, nerves and aesthetical zones.
On the skin, radiofrequency surgery is used for removing of furunculus and carbunculus, especially in the middle third of the face, to prevent spreading of infections towards the cavernous sinus, and sagittal venous sinus. It is suitable for removing of nevi, papillomas, fibromas, haemangiomas, keratoses and small capillaries of the face. Removing of these is done with the incision which is light, without pressure, and simultaneous. Healing of the wound is fast, and the creation of scar tissue is minimal. Because of that, we have ideal cosmetic results on the skin.
The effect of coagulation with radiowave device depends on the amount of water in the tissue, which means that when the percentage of water is larger, so is the resistance, and then the coagulation is weaker. The water evaporates, coagulation of the tissue and resistance are rising up to the point in which electricity is not transferred. For this reason, it is very important that the working area (field) is absolutely dry in the moment of coagulation. It is achieved with good synchronicity of work between oral surgeon and his assistant. Different types of tissues have different resistance for the transmission of electricity. For tissues with higher resistance we need bigger working voltage and vice versa. Because of that, it is extremely important to pick adequate active electrode and working mode so that we can have optimal results in shorter time of duration.
It is important to notice that radiowave device with its effect can destabilize the activity of the heart's pacemaker. For this reason, it is necessary to put passive electrode farther from it. After the surgical procedure, it is necessary to control how the pacemaker works.
Aways when it is possible in that situation bipolar method should be used. Electricity does not pass through the body, buth from one end of bipolar tweezars to the other end, making electricity circuit and coagulation.
If patient has dental implants, touching them is contraindicated while working with active electrode.
Complications are often caused bu bad practice, or avoiding principes of working with this appliance.
This may cause burns, lateral tissue damage, that lead to long lasting wound healing and making great scars.