From Big Medical Encyclopedia

DIATHERMOCOAGULATION (a diathermy + coagulation) — a medical method of impact on living tissues heat which is formed in them during the passing of current of high frequency. The method is entered in to lay down. to the practician in 1905 by the Czech doctor R. Zeyneck. Is founded on heating of fabrics to temperature, at a cut there is irreversible coagulation of proteins. Spark and electronic and lamp generators are a source of electric current of high frequency at D. (see. Diathermy ). Temperature increase on the limited site of a surface of fabric in the place of its contact with an electrode is reached thanks to the high density of alternating electric current with a frequency of fluctuation of 1000 — 1500 kHz. The amount of the formed heat variously for different fabrics and according to Joule-Lenz law with other things being equal depends on their full electric resistance. In process of removal from electrodes density of current decreases, at the same time also the effect of coagulation decreases.

Fig. 1. The scheme of an arrangement of electrodes at a bipolar monoactive way of diathermocoagulation: at the left — active, on the right — passive.
Fig. 2. The scheme of an arrangement of active electrodes at a bipolar biaktivny way of diathermocoagulation of the tumor acting over a surface.

Carry out by means of special devices — diathermocoagulators. There are two methods D.: monopolar when patient attach only to one pole of a source of current, and bipolar when patient attach to both poles. At a bipolar method depending on the surface area of electrodes and their activity distinguish: a bipolar monoactive method when electrodes have different size — one with a big surface (passive), another with a small surface (active), and bipolar biaktivny method when apply two identical small active electrodes which are located close from each other (fig. 1 and 2). At a bipolar monoactive method the mobile electrode because of the small area of contact with fabrics provides considerable heating at the expense of the high density of current under it; the passive electrode considerably of the bigger area is strengthened from the place at a distance to lay down. influences (on a hip, a buttock, in lumbar area, etc.), providing its good prileganiye to skin in order to avoid a burn. This method in a wedge, practice is applied more often.

Fig. 3. A set of various active electrodes and the holder with the inserted electrode (below).

Apply to a stop of bleeding from small vessels at surgeries for what the vein captured by the ends of a styptic clip or tweezers is coagulated a touch of an active electrode, and also for removal or destruction of a row patol, educations. As the indication for D. serve new growths of skin, a throat, a digestive tract, a rectum, an erosion of a neck of uterus, papilloma and an ulcer of a wall of a bladder, amotio of a retina of an eye, etc. At D. depending on the aims which she pursues use active electrodes of various form: in the form of a disk, a spear, tweezers, a ball or an edge of a scalpel (fig. 3).

If an active electrode 1 — 2 mm from the surface of education have at distance, then coagulation of fabrics comes from a bunch of electric discharges or single sparks — a diatermokarbonization. Hl use method of carbonization. obr. in cosmetic surgery for coagulation of superficial cutifications.

D.'s use caused development of the whole industry of surgery — electrosurgeries (see), in a cut basic elements of interventions — a section of fabrics (elektrokoagulotomiya) and excision of various educations make (electroscission), using currents of high frequency. The electrosurgery finds application in ophthalmology, urology, dermatology, stomatology, medical cosmetics and especially in oncology since coagulation of fabrics in the field of a section leads of them to death of malignant cells and interferes with their dissimination during operation.

For a section of fabrics there is a special device EN-57 with the factory name «The Device for Coagulation and Cutting by Current of High Frequency», or «Elektronozh». Elektrokoagulotomiya is made an active electrode, carrying out it by the bystry movement on a surface of the diconnected fabric. The narrow and equal wound is formed. Due to the high density of current under an active electrode there is intensive calorification owing to what the liquid which is in cells of fabric, instantly («with explosion») evaporates and breaks off them through bystry advance of an electroknife. At slow advance of an active electrode the section of fabrics happens to coagulation of edges of a wound — a diatermokoagulotomiya.

The main condition of successful D. — dryness of a surface of influence (a wound, education etc.). It is never necessary to bring to a carbonization of fabric since the charred fabric sticks to an electrode and at its otnyatiya it is broken off that can cause bleeding. Therefore at D.'s performance it is necessary to have an opportunity to instantly switch on and off current for what the special pedal or the switch serves in the handle of an active electrode.

Contraindications: proximity of large vascular and nervous educations, bleeding from vessels of a large diameter.

Complications: widespread rough keloid cicatrixes, secondary bleedings from the vessels which underwent a carbonization as a result of misuse of D., a burn of skin at leaky fixing of a passive electrode because of passing of spark categories are possible. At D.'s use it is necessary to consider potential of explosion of a method.

DIATHERMOCOAGULATION in gynecology — see. Uterus .

Bibliography: Liventsev H. M and Livenson A. R. Electromedical equipment, M., 1974.

L. S. Tapinsky.