Methods of hysteroscopy

Gas Hysteroscopy

Expansion medium

With gas hysteroscopy, carbon dioxide is used to expand the uterine cavity. For the first time, the use of CO ₂ in hysteroscopy was reported by Rubin in 1925. A hysterophilic device is used to supply gas to the uterine cavity. When performing diagnostic hysteroscopy, sufficient pressure in the uterine cavity is 40-50 mm Hg, and the gas flow rate is more than 50-60 ml / min. The most important indicator is the gas feed rate. When gas is supplied at a rate of 50-60 ml / min, even its entry into the vein is not dangerous, since carbon dioxide readily dissolves in the blood. At a CO ₂ injection rate of more than 400 ml / min, acidosis occurs, so a toxic effect of CO ₂ in the form of cardiac abnormalities occurs, and at a gas flow rate of 1000 ml / min death occurs (Lindemann et al., 1976, Galliant, 1983). At a pressure of more than 100 mm Hg. And a CO ₂ feed rate of more than 100 ml / min, gas embolism cases have been described. Therefore, the use of a laparoscopic insufflator or any other device not intended for hysteroscopy is unacceptable for gas delivery to the uterine cavity. This can lead to uncontrolled supply of gas at high speed and cause the above complications.

Diagnostic hysteroscopy usually lasts for several minutes, and a small amount of gas entering the abdominal cavity is usually quickly absorbed without causing any complications. Sometimes, with good patency of the fallopian tubes, the gas enters the abdominal cavity, and there may be slight pain in the right shoulder, which are self-healing after a while. Gas hysteroscopy is easy to perform and gives a very good overview of the uterine cavity, especially in postmenopausal women and in the proliferative phase of the menstrual cycle. With the presence of blood in the uterine cavity, CO ₂ causes the formation of vesicles that limit the vision. In this situation, a transition to liquid hysteroscopy is necessary.

CO ₂ does not support combustion, so it can be safely used in electrosurgery, as it was done during the introduction of hysteroscopic sterilization by coagulation of the uterine tubes.

But for long-term operations, carbon dioxide is unacceptable, as it does not provide adequate conditions because of significant leakage through the fallopian tubes, the cervical canal and the operating canal.

In addition, gas hysteroscopy is undesirable to perform with cervical deformity when it is impossible to create sufficient tightness and achieve a full expansion of the uterine cavity, and when trying to use adapter neck caps there is a risk of injury to the cervix. With the germination of the myometrium by a cancerous tumor, the hermetic closure of the cervix by the adapter can promote the rupture of the uterus even at low gas pressures.

Due to the possible risk of gas embolism, CO _{2 is} not used for scraping the uterine cavity. The disadvantages of gas hysteroscopy can also be attributed to the difficulty of acquiring CO ₂.

The use of carbon dioxide is advisable in the conduct of diagnostic hysteroscopy and the absence of bloody discharge.

Thus, gas hysteroscopy has the following drawbacks:

1. Impossibility of surgical interventions in the uterine cavity.
2. Impossibility of hysteroscopy with uterine bleeding.
3. Risk of gas embolism.
4. Expensiveness.

Equipment

When carrying out gas hysteroscopy, it is better not to expand the cervical canal, but if necessary, Gegar dilators up to No. 6-7 are inserted into the cervical canal.

Depending on the size of the cervix, a cap-adapter of the appropriate size is selected. In the channel of the adapter enter the expander Gegar to No. 6-7, with which (after removing the bullet forceps from the cervix), the cap is put on the cervix and fixed on it by creating a negative pressure in the cap using a special syringe or vacuum suction.

After removing the expander from the adapter canula, a hysteroscope body is inserted into the uterine cavity without an optical tube. Through the channel of the body, 40-50 ml of isotonic sodium chloride solution (for washing the uterine cavity from the blood) are injected into the uterine cavity, then the solution is removed by suction.

The optic tube is connected to the optical tube of the hysteroscope, the optics are fixed to the hysteroscope body. To one of the valves in the body, a tube is connected to receive CO ₂ from the hysterophilator at a rate of 50-60 ml / min, with the pressure in the uterine cavity not exceeding 40-50 mm Hg.

Fluid Hysteroscopy

Expansion medium

Most surgeons prefer liquid hysteroscopy. With sufficiently clear visibility, liquid hysteroscopy makes it easy to control the flow of hysteroscopic operations.

The liquid is fed into the uterine cavity at a certain pressure. Very low pressure will worsen the review, not allowing adequately to expand the uterine cavity and tampon damaged vessels. Too high a pressure will provide excellent visibility, but the liquid will under pressure enter the circulatory system with the risk of significant fluid overload and metabolic disturbances. Therefore, it is desirable to control the pressure in the uterine cavity at a level of 40-100 mm Hg. Measurement of intrauterine pressure is desirable, but not necessary.

The fluid flowing through the tap of the outflow or the enlarged cervical canal is necessary to collect and constantly measure its volume. Loss of liquid should not exceed 1500 ml. With diagnostic hysteroscopy, these losses usually do not exceed 100-150 ml, for small operations 500 ml. With the perforation of the uterus, the loss of fluid immediately increases dramatically, it stops flowing through the tap or cervix, remaining in the abdominal cavity.

There are high- and low-molecular fluids for the expansion of the uterine cavity.

High molecular weight media: 32% dextran (giscon) and 70% dextrose. They support the necessary stretching of the uterine cavity, do not mix with blood and provide a good overview. Introducing a syringe into the uterine cavity, even 10-20 ml of such a solution is sufficient to ensure a clear view. But high-molecular solutions are quite expensive and very viscous, which creates difficulties in the work. Careful cleaning and flushing of the tools is necessary in order to avoid blockage of the cranes for supply and drainage of the liquid when these solutions dry out. The most significant drawback of these media is the possibility of anaphylactic reaction and coagulopathy. If the hysteroscopy is delayed, dextran can enter the abdominal cavity and, absorbed into the vascular bed due to its hyperosmolar properties, cause its overload, which can lead to pulmonary edema or DIC syndrome. Cleary et al. (1985) in their studies showed that for every 100 ml of high molecular weight dextran that enters the vascular bed, the volume of circulating blood increases by 800 ml. In addition, the absorption of these solutions from the abdominal cavity occurs slowly and reaches a peak only to the 3-4th day.

In view of all these drawbacks, high molecular weight liquid media are currently used extremely rarely, and in some countries (for example, in the UK) they are forbidden to use in hysteroscopy.

Low-molecular solutions: distilled water, saline solution, Ringer and Hartmann solutions, 1.5% glycine solution, 3 and 5% sorbitol solution, 5% glucose solution, mannitol. These are the main expanding media used in modern hysteroscopy.

1. Distilled water can be used for diagnostic and surgical hysteroscopy, short manipulations and operations. It is important to know that when more than 500 ml of distilled water is absorbed into the vascular bed, the risk of intravascular hemolysis, hemoglobinuria and, consequently, renal failure increases.
2. Physiological saline, solutions of Ringer and Hartmann - accessible and cheap environments. These fluids are isotonic with blood plasma and are easily removed from the vascular system without creating serious problems. Isotonic solutions are successfully used for hysteroscopy in the background of uterine bleeding, as they readily dissolve in the blood, wash out blood and fragments of cut tissue from the uterine cavity, and provide good visibility. These solutions are unacceptable in electrosurgery because of their electrical conductivity, are recommended only for diagnostic hysteroscopy, operations with mechanical tissue dissection and laser surgery.
3. For electrosurgical operations, non-electrolyte solutions of glycine, sorbitol and mannitol are used. It is acceptable to use 5% glucose solution, rheopolyglucin and polyglucin. They are quite cheap and affordable, but when using them, careful monitoring of the volume of injected and withdrawn liquid is necessary. The difference should not exceed 1500-2000 ml to avoid a significant increase in the volume of circulating blood, leading to electrolyte disorders, pulmonary edema and brain.
   • Glycine is a 1.5% solution of the amino acid glycine, the first use of which was described in 1948 (Nesbit and Glickman). When absorbed, glycine is metabolized and excreted by the kidneys and liver. Therefore, glycine is administered with caution in case of impaired liver and kidney function. Cases of hyponatremia of dilution have been described in both transurethral resection of the prostate and intrauterine resectoscopy.
   • 5% sorbitol, 5% glucose - isotonic solutions, easily mix with blood, provide fairly good visibility, quickly removed from the body. If a large number of these solutions get into the vascular bed, hyponatremia and postoperative hyperglycemia are possible.
   • Mannitol - a hypertonic solution with a strong diuretic effect, mainly removes sodium and very little - potassium. As a result, mannitol can cause significant electrolyte disturbances and pulmonary edema.

So, the liquid media used to expand the uterine cavity have the following drawbacks:

• Reducing the field of view by 30 °.
• Increased risk of infectious complications.
• The risk of anaphylactic shock, pulmonary edema, coagulopathy when using high molecular weight solutions.
• Ability to overload the vascular bed with all the ensuing consequences.

Equipment

When carrying out liquid hysteroscopy using various mechanical devices for fluid supply, it is desirable to maximally expand the cervical canal for better outflow of fluid (Gegar dilators to No. 11-12).

When using a system with a constant supply and outflow of fluid and an operating hysteroscope (Continuous flow), it is advisable to expand the cervical canal to No. 9-9.5.

The telescope is placed in the hysteroscope body and fixed with a locking lock. To the hysteroscope, connect a flexible light guide with a light source, a conductor connecting the device with a medium for expanding the uterine cavity, and a video camera. Before the introduction of the hysteroscope into the uterine cavity, the flow of the fluid intended for expansion of the uterine cavity is checked, the light source is turned on and the camera is focused.

The hysteroscope is inserted into the cervical canal and under the vision control is gradually advanced inside. They wait for the time necessary for a sufficient expansion of the uterine cavity. Orientations that make sure that the hysteroscope is located in the cavity serve the oviducts of the fallopian tubes. If the examination is interfered with by gas bubbles or blood, you need to wait a bit until the leakage fluid takes them out.

First, it is better to introduce a hysteroscope with a half-open tap for liquid influx and a fully open tap for outflow. If necessary, these valves can be partially closed or fully opened to regulate the extent of the uterine cavity extension and improve visibility.

Carefully carefully examine all the walls of the uterine cavity, the area of the uterine tubes, and at the exit - the cervical canal. During examination, attention should be paid to the color and thickness of the endometrium, its correspondence to the day of the menstrual-ovarian cycle, the shape and size of the uterine cavity, the presence of pathological formations and inclusions, the relief of the walls, the state of the uterine tubes.

If a focal pathology is found, the endometrium is guided by biopsy using biopsy forceps conducted through the operating channel of the hysteroscope. In the absence of focal pathology, the telescope is removed from the uterus and a separate diagnostic curettage of the uterine mucosa is performed. Curettage can be mechanical and vacuum.

The main causes of poor visibility may be gas bubbles, blood and insufficient lighting. When liquid hysteroscopy is used, the fluid delivery system must be closely monitored to avoid the entry of pressurized air, and to maintain an optimal fluid delivery rate for washing the uterine cavity from the blood.

Microhysteroscopy

Currently, there are two types of microhysteroscope Hamou - I and II. Their characteristics were presented above.

Microhysteroscope I is an original multi-purpose tool. With its help it is possible to examine the mucous membrane of the uterus both macro- and microscopically. Macroscopically, the mucosa is examined using a panoramic view, microscopic examination of cells is carried out using a contact method after intravital staining of the cells.

First, an ordinary panoramic examination is carried out, with special attention being paid, if possible, to atraumatic passage through the cervical canal under constant vision control.

Gradually promoting the hysteroscope, inspect the mucous membrane of the cervical canal, then panoramic view the entire cavity of the uterus, rotating the endoscope. If there is a suspicion of atypical changes in the endometrium, a straight eyepiece is changed on the lateral and a panoramic examination of the mucous membrane of the uterine cavity is made with a 20-fold increase. With such an increase, it is possible to assess the density of the glandular structures of the endometrium, as well as the presence or absence of dystrophic and other changes, the character of the location of the vessels. At the same magnification, a detailed examination of the mucous membrane of the cervical canal, especially of its distal part (cervicoscopy), is carried out. Then conduct microlithogetheroscopy.

The first stage of examination of the cervix with a microhysteroscope (20-fold increase) - colposcopy. Then the cervix is treated with a solution of methylene blue. The magnification is changed by 60-fold and microscopic examination is performed with a straight eyepiece by touching its distal end of the cervical tissue. Screw the image. This increase allows us to investigate cellular structures, identify atypical sites. Particular attention is paid to the transformation zone.

The second stage of micro-colposcopy is examination of the cervix with a 150-fold increase in the image, a check at the cellular level. Inspection is carried out through the lateral eyepiece, the distal end is pressed against the epithelium. With such an increase, only pathological areas are examined (for example, the proliferation zones).

The method of microcolloguscopy is rather complicated, it requires a lot of experience not so much in hysteroscopy as in cytology and histology. The difficulty in evaluating the image is also in the fact that the examination of the cells is carried out after an intravital staining. For the reasons listed above, the microhysteroscope I and microcampohysteroscopy have not been widely used.

Microhysteroscope II is widely used in operative hysteroscopy. This model allows a panoramic examination of the uterine cavity without enlargement, macrohysteroscopy with a 20-fold magnification and microhysteroscopy with a magnification of 80 times. The method of application is the same as described above. Using the microhysteroscope II, surgical hysteroscopic interventions are performed using semi-rigid and rigid surgical endoscopic instruments. In addition, a resectoscope is used with the same telescope.

[1], [2], [3], [4], [5], [6], [7], [8]