Types of electrosurgery

Distinguish between monopolar and bipolar electrosurgery. With monopolar electrosurgery, the entire body of the patient is the conductor. The electric current passes through it from the surgeon's electrode to the patient's electrode. Previously, they were called active and passive (return) electrodes, respectively. However, we are dealing with an alternating current where there is no constant motion of charged particles from one pole to another, but their rapid oscillations occur. The electrodes of the surgeon and the patient differ in size, area of contact with the tissues and relative conductivity. In addition, the very term "passive electrode" causes insufficient attention of physicians to this plate, which can become a source of serious complications.

Monopolar electrosurgery is the most common system for supplying radio-frequency current in both open and laparoscopic interventions. It is quite simple and convenient. The use of monopolar electrosurgery for 70 years has shown its safety and effectiveness in surgical practice. It is used both for cutting (cutting) and for coagulation of tissues.

In bipolar electrosurgery, the generator is connected to two active electrodes mounted in one instrument. The current passes through only a small portion of tissue, sandwiched between the brushes of the bipolar instrument. Bipolar electrosurgery is less universal, requires more complex electrodes, but is safer, since it affects the tissues locally. They work only in coagulation mode. The patient's plate is not used. The use of bipolar electrosurgery is limited by the absence of a cutting regime, burning out the surface and accumulation of carbon on the working part of the instrument.

Electrical circuit

A necessary condition for high-frequency electrosurgery is the creation of an electrical circuit, along which the current moves, producing cutting or coagulation. The components of the circuit are different when using monopolar and bipolar electrosurgery.

In the first case, the complete chain consists of ECG, which supplies the voltage of the surgeon's electrode, the patient's electrode and the cables connecting them to the generator. In the second case, both electrodes are active and combine with ECG. When the active electrode touches the tissues, the circuit is closed. In this case, it is referred to as an electrode under load.

Current always goes along the path of least resistance from one electrode to another.

With an equivalent resistance of tissues, the current always chooses the shortest path.

Unconnected, but energized circuit can cause complications.

In hysteroscopy, only monopolar systems are used so far.

Hysteroscopic equipment for electrosurgery consists of a generator of high-frequency voltage, connecting wires and electrodes. Hysteroscopic electrodes are usually placed in a resectoscope.

Sufficient expansion of the uterine cavity and good visibility are important for the use of electrosurgery.

To the expanding environment in electrosurgery, the basic requirement is the absence of electrical conductivity. For this purpose, high- and low-molecular liquid media are used. The advantages and disadvantages of these media are mentioned above.

The overwhelming majority of surgeons use low-molecular liquid media: 1.5% glycine, 3 and 5% glucose, rheopolyglucin, polyglucin.

Basic principles of working with resectoscope

1. Quality image.
2. Activation of the electrode only when it is in the zone of visibility.
3. Activation of the electrode only when it moves towards the body of the resectoscope (passive mechanism).
4. Constant monitoring of the volume of injected and withdrawn liquid.
5. Termination of surgery with a fluid deficit of 1500 ml or more.

Principles of laser surgery

The surgical laser was first described by Fox in 1969. In gynecology, the first CO ₂ laser was used by Bruchat et al. In 1979 during laparoscopy. In the future, with the improvement of laser technology, their use in operative gynecology was expanding. In 1981, Goldrath et al. For the first time, the endometrial photovaporization was performed with an Nd-YAG laser.

Laser - an instrument that generates coherent light waves. The phenomenon is based on the emission of electromagnetic energy in the form of photons. This occurs as the excited electrons return from the excited state (E2) to the quiet state (E1).

Each type of laser has its own wavelength, amplitude and frequency.

The laser light is monochromatic, has one wavelength, i.e. It is not divided into composite components like ordinary light. Since the laser light is very slightly scattered, it can be focused strictly locally, and the area of the surface illuminated by the laser will practically not depend on the distance between the surface and the laser.

In addition to the power of the laser, there are other important factors affecting the photon: tissue - the degree of absorption, refraction and reflection of laser light by tissue. Since water enters the composition of each tissue, any tissue under laser action boils and evaporates.

The light of argon and neodymium lasers is completely absorbed by the pigmented tissue containing hemoglobin, but is not absorbed by water and a transparent tissue. Therefore, when using these lasers, evaporation of tissues is less effective, but they are successfully used for coagulation of bleeding vessels and ablation of pigmented tissues (endometrium, vascular tumors).

In hysteroscopic surgery, the most commonly used Nd-YAG laser (neodymium laser), giving light with a wavelength of 1064 nm (invisible, infrared spectrum). The neodymium laser has the following properties:

1. The energy of this laser is easily transferred through the light guide from the laser generator to the required point of the operating field.
2. The energy of an Nd-YAG laser is not absorbed when passing through water and transparent liquids, does not create a directed motion of charged particles in electrolytes.
3. The Nd-YAG laser produces a clinical effect due to coagulation of tissue proteins and penetrates to a depth of 5-6 mm, i.e. Deeper than CO ₂ -laser or argon laser.

When an Nd-YAG laser is used, energy is transmitted through the emitting end of the fiber. The minimum power of the current suitable for treatment is 60 W, but since there is a small energy loss at the emitting end of the fiber, it is better to use 80-100 W power. The lightguide usually has a diameter of 600 μm, but lightguides with a large diameter of 800, 1000, and 1200 μm can also be used. An optical fiber with a large diameter destroys a large tissue surface in a unit of time. But since the impact of energy must be spreading inward, the fiber must move slowly to achieve the desired effect. Therefore, most surgeons using the laser technique use a standard fiber with a diameter of 600 μm, conducted through the operating channel of the hysteroscope.

Only some of the power of laser energy is absorbed by tissues, 30-40% of it is reflected and dissipated. Dispersion of laser energy from tissues is dangerous for the surgeon's eyes, therefore it is necessary to use special protective lenses or glasses if the operation is performed without a video monitor.

The fluid used to expand the uterine cavity (saline solution, Hartmann's solution) is fed into the uterine cavity at constant pressure and simultaneously aspirated to ensure good visibility. To do this, it is better to use an endomat, but you can apply a simple pump. It is desirable to carry out the operation under the control of a video monitor.

There are two methods of laser surgery - contact and non-contact, detailed described in the section of surgical procedures.

In laser surgery, the following rules must be observed:

1. Activate the laser only at the time when the emitting end of the fiber is visible.
2. Do not activate the laser in the stationary state for a long time.
3. Activate the laser only when moving towards the surgeon and never when returning it to the bottom of the uterus.

Observance of these rules helps to avoid perforation of the uterus.