Endometrial resection (ablation)

Resection (ablation) of the endometrium

Uterine bleeding (menorrhagia and metrorrhagia), recurrent and leading to anemia, are often an indication for hysterectomy. Hormonal therapy does not always have a positive effect, and it is contraindicated for some women. For many years, researchers have looked for various methods of treating uterine bleeding in order to avoid hysterectomy. Endometrial ablation was first proposed by Bardenheuer in 1937. Its essence consists in removing the entire thickness of the endometrium and the superficial part of the myometrium. Different approaches have been proposed over the years to achieve this. Initially, chemical and physical methods were developed. Thus, Rongy in 1947 reported on the introduction of radium into the uterine cavity. Droegmuller et al. in 1971 used cryodestruction to destroy the endometrium. This idea was later developed and improved in the works of V.N. Zaporozhan et al. (1982, 1996) and others. Shenker and Polishuk (1973) introduced chemicals into the uterine cavity to destroy the endometrium and cause uterine cavity closure. Attempts were made to introduce hot water into the uterine cavity, but this method was not used due to thermal complications.

In 1981, Goldrath et al. first performed photovaporization of the endometrium with a Nd-YAG laser using a contact technique that involved the destruction of the entire endometrium, resulting in secondary amenorrhea. Since then, the number of studies on endometrial ablation has increased rapidly.

In 1987, Leffler proposed a modification of laser ablation - a non-contact method (the so-called bleaching technique).

Subsequently, with the introduction of the hysteroresectoscope, interest in operative hysteroscopy significantly increased again, including in terms of its use for endometrial resection. De Cherney and Polan were the first to propose using a hysteroresectoscope for endometrial resection in 1983. Improvements in endoscopic equipment, especially over the past 5-10 years (high-frequency voltage generator, a set of different electrodes, a device for continuous fluid supply with constant pressure and simultaneous fluid suction), have led to the widespread use of endometrial electroresection.

Currently, the two most commonly used methods of ablation (resection) of the endometrium are laser and electrosurgical.

However, the search for new methods continues. Thus, in 1990, Phipps et al. proposed the use of radiofrequency electromagnetic energy for ablation of the endometrium. This method is based on heating the endometrium (including the basal layer) with a special conductor inserted into the uterine cavity. This is a disposable conductor, at the tip of which there is a plastic balloon with 12 plate-shaped electrodes (VALLEYLAB VESTA DUB Treatment System).

It is known that at temperatures above 43 °C, depending on the duration of exposure, the tissues of the human body undergo irreversible changes as a result of protein denaturation and cell damage. The VESTA conductor is inserted into the uterine cavity and air is pumped until the electrodes are in close contact with the surface of the uterine walls, then the electric device is turned on to supply energy. The endometrium is heated to 75 °C, the therapeutic effect time is 4 minutes with full contact of the electrode plates with the surface of the uterine walls. This method does not require the use of hysteroscopy. According to research, the effectiveness of the method is quite high, but it has not yet found wide application, and the long-term results of such treatment are also unknown.

In 1995, Loftier proposed a method of endometrial ablation using a heating element inside a latex balloon. This balloon is placed in the uterine cavity on the tip of the applicator [Cavaterm (Wallsten MEDICAL)]. After the balloon is inserted into the uterine cavity, glycerin is pumped into it, then the heating element is turned on, which causes the glycerin in the balloon to heat up, and the temperature on the balloon surface should be 75 °C. According to the author, this method is indicated for inoperable uterine cancer or uterine perforation, since in this case it is impossible to create and maintain sufficient pressure in the uterine cavity. The destruction zone is from 4 to 10 mm, the application time required to create it is 6-12 minutes. A number of authors estimate the effectiveness of this method at 90%.

To date, there is no clarity among gynecologists regarding the terminology: what is considered endometrial ablation and when to use the term "endometrial resection". Endometrial ablation - destruction of the entire thickness of the endometrium - can be laser and electrosurgical. With this operation, it is impossible to take tissue for histological examination. Endometrial resection - excision of the entire thickness of the endometrium - can only be electrosurgical: a cutting loop excises the entire mucous membrane in the form of shavings. With this type of operation, it is possible to conduct a histological examination of the excised tissue.

The endometrium is a tissue with a high capacity for regeneration. To obtain the effect of these treatment methods, it is necessary to prevent the restoration of the endometrium by destroying its basal layer and glands.

To date, there are no clear indications for endometrial ablation or resection. At the same time, most endoscopist surgeons believe that indications for these surgical interventions include the following conditions:

1. Recurrent, heavy, prolonged and frequent uterine bleeding with the ineffectiveness of conservative treatment methods and the absence of data on malignant pathology of the internal genital organs in patients over 35 years of age.
2. Recurrent hyperplastic processes of the endometrium in pre- and postmenopausal patients.
3. Proliferative processes of the endometrium in postmenopause when hormonal therapy is impossible.

Some doctors believe that in the case of recurrent hyperplastic processes of the endometrium during the postmenopausal period, it is advisable to combine ablation (resection) of the endometrium with laparoscopic adnexectomy, since almost all patients in this group have pathological processes in one or both ovaries (usually hormone-secreting structures).

Some endoscopists recommend endometrial ablation for algomenorrhea, premenstrual syndrome, and bleeding caused by hormone replacement therapy. However, this issue is still under debate.

When deciding on endometrial ablation (resection), in addition to a general clinical examination, it is necessary to exclude other causes of uterine bleeding. Therefore, mandatory examinations include examination of the thyroid gland, hormonal status, and skull (sella turcica) radiography. The examination plan also includes cytological examination of smears taken from the mucous membrane of the cervix, colposcopy, and ultrasound of the pelvic organs with vaginal and abdominal sensors, which provide additional information about the size of the uterus, the thickness of the endometrium, the presence and localization of myomatous nodes, their size, and the condition of the ovaries. With large sizes of the uterine cavity and deep adenomyosis, the percentage of failures and complications increases.

Indications for ablation (resection) of the endometrium are formulated taking into account the following factors:

1. A woman's unwillingness to maintain reproductive function.
2. Refusal of hysterectomy (desire to preserve the uterus) or the danger of performing it using the open method.
3. The size of the uterus is no more than 10-12 weeks of pregnancy.

Contraindications. The presence of fibroids is not considered a contraindication to ablation (resection) of the endometrium, provided that none of the nodes exceeds 4-5 cm. Otherwise, the operation is contraindicated. Prolapse of the uterus is also considered a contraindication.

Endometrial ablation (resection) does not guarantee amenorrhea and sterilization; the patient should be warned about this.

Hysteroscopy is performed in advance to assess the condition of the uterine cavity, its size and contours with a histological examination of the mucous membrane of the uterus and cervical canal to exclude atypical changes in them. Women with established atypical changes in the endometrium and malignant lesions of the internal genital organs cannot be subjected to ablation (resection) of the endometrium.

Endometrial preparation. It has been proven that the Nd-YAG laser beam and electrical energy from the electrosurgical loop and ball electrode destroy tissue to a depth of 4-6 mm. At the same time, even during a normal menstrual cycle, the thickness of the endometrium changes from 1 mm in the early proliferation phase to 10-18 mm in the secretory phase. Therefore, to obtain optimal results in ablation (resection) of the endometrium, its thickness should be less than 4 mm. To achieve this, the operation must be performed in the early proliferation phase, which is not always convenient for both the patient and the doctor.

Some authors suggest performing mechanical or vacuum curettage of the uterus immediately before the operation, considering it an effective alternative to drug suppression of the endometrium. In this case, the procedure becomes cheaper and more accessible, and allows avoiding numerous undesirable side effects of hormonal therapy. In addition, the operation can be performed regardless of the day of the menstrual cycle and allows for histological examination of the endometrium immediately before its ablation.

However, many surgeons believe that curettage does not thin the endometrium sufficiently and, therefore, prefer to prepare the endometrium using hormones. With hormonal suppression of the endometrium, its ablation (resection) can be performed with the thinnest endometrium, in addition, hormonal preparation worsens the blood supply to the uterus and reduces the size of its cavity. This reduces the time of the operation, reduces the risk of significant fluid overload of the vascular bed and increases the proportion of successful results.

According to the authors of the book, hormonal preparation is necessary if endometrial ablation (laser or electrosurgical) is planned and if the uterus is larger than 7-8 weeks of pregnancy. Hormonal preparation is not necessary if endometrial resection with loop electrodes is planned.

For the purpose of hormonal preparation, various drugs are used: GnRH agonists (zoladex, 1-2 injections of decapeptyl depending on the size of the uterus), antigonadotropic hormones (danazol 400-600 mg daily for 4-8 weeks) or gestagens (norethisterone, medroxyprogesterone acetate, norcolut 10 mg daily for 6-8 weeks), etc.

Important organizational points (especially for a novice endoscopist): a set of necessary equipment, liquid media for stretching the uterine cavity in sufficient quantity, the correct choice of electrode and parameters of the energy used, etc.

Necessary equipment and tools

1. Hysteroresectoscope with electrodes and high-frequency voltage generator.
2. Nd-YAG laser with operating hysteroscope.
3. Solutions for expansion of the uterine cavity and a system for their delivery under constant pressure with simultaneous suction (endomat).
4. Light source, preferably xenon.
5. Video camera with monitor.

It is recommended to use a telescope with a viewing angle of 30°, but this depends on the experience and habits of the surgeon. The use of a video monitor and an intense light source is of great importance for the safety, accuracy and correctness of the operation.

Dilating medium. Most endoscopists prefer to perform endometrial ablation (resection) using liquid hysteroscopy, as the liquid provides a clear view and easy control of the operation. Only Gallinat recommends using CO2 _as a dilating agent for endometrial ablation.

The choice of fluid for uterine cavity expansion depends on the proposed surgical method. Electrosurgical surgery requires non-electrolyte solutions (1.5% glycine, 5% glucose, rheopolyglucin, polyglucin, etc.), while laser surgery can use simple fluids - saline, Hartmann's solution, etc. For the safety of the operation, it is necessary to remember the fluid supply rate and the pressure in the uterine cavity, constantly monitor the amount of fluid introduced and removed to avoid possible complications. The pressure in the uterine cavity should be within 40-100 mm Hg.

For electrosurgical resection of the endometrium, most surgeons use a cutting loop with a diameter of 8 mm, removing tissue within a radius of 4 mm with one cut, which avoids re-passing the same area. When using a loop of a smaller diameter (4 or 6 mm), the same area must be passed twice to achieve an optimal result, which creates a danger during the operation. But these loops are convenient for working in hard-to-reach places (the area of the mouths of the fallopian tubes). Here, you need to be especially careful, since the thickness of the myometrium in these places does not exceed 4 mm. The depth of tissue burn damage depends not only on the size of the loop, but also on the time of exposure to the tissue and the power of the current used. Slow movement of the loop at high power significantly damages the tissue. The current power should be 100-110 W in cutting mode.

Endometrial ablation is performed using a ball or cylindrical electrode. Its shape best matches the inner surface of the uterus, which allows for a quick operation with less damage. When using ball and cylindrical electrodes, a current of 75 W is used in coagulation mode.

Some doctors believe that in the initial stages of mastering the technique to prevent uterine perforation, ablation (resection) of the endometrium should be performed under laparoscopic control.

The combined use of endometrial ablation (resection) with laparoscopy is also advisable in the following situations:

1. Resection of large and deep myomatous nodes along with endometrial resection.
2. Sterilization. In this case, sterilization is performed first, and then ablation (resection) of the endometrium is performed to prevent fluid from entering the abdominal cavity through the fallopian tubes.
3. Endometrial ablation (resection) in a patient with a bicornuate uterus or a thick uterine septum.

After ablation (resection) of the endometrium (both electrosurgical and laser), complete amenorrhea does not occur in everyone. Before the operation, the woman must be warned that hypomenorrhea (a significant reduction in menstrual bleeding) is considered a good outcome. According to various authors, amenorrhea is recorded in 25-60% of cases. The effect of the operation lasts for 1-2 years in approximately 80% of those operated on.

The patient's age, the size of the uterine cavity, and the presence of adenomyosis influence the outcome of the operation. The best results are obtained in women aged 50 and older with small uterine sizes. Currently, many studies have appeared on repeated endometrial ablation.

Even with complete amenorrhea, the risk of pregnancy after endometrial ablation remains, so patients of reproductive age are recommended to undergo sterilization before the operation. There is also a risk of ectopic pregnancy, and in the case of intrauterine pregnancy, due to deterioration of the blood supply to the uterus, there may be developmental disorders of the fetus and placenta (for example, the risk of true placenta accreta increases). The woman must be informed about these problems.

Hormonal replacement therapy is not contraindicated after endometrial ablation.

Anesthesia. The operation is usually performed under general intravenous anesthesia or epidural anesthesia. If the operation is performed together with laparoscopy, endotracheal anesthesia is used.

Electrosurgical ablation of the endometrium technique

The patient is placed on the operating chair, as in minor gynecological surgeries. A bimanual examination is performed beforehand to determine the position of the uterus and its size. After the external genitalia have been treated, the cervix is fixed with bullet forceps, the cervical canal is widened with Hegar dilators to No. 9-10 (depending on the resectoscope model and the size of its outer body). The patient is placed in the Trendelenburg position to retract the intestines in the cephalic direction to avoid serious complications. Before starting work, it is important to make sure that there is no air in the irrigation system, as well as the serviceability and integrity of the electrical wires, and their correct connection.

After this, the resectoscope is inserted into the uterine cavity. Each side of the uterus is examined in detail, especially if diagnostic hysteroscopy was not performed before the operation. The detection of endometrial polyps or small submucous nodes is not a contraindication to surgery. If a septum in the uterine cavity or a bicornuate uterus is diagnosed, the operation is not abandoned, but it is performed extremely carefully, slightly changing the technique. If areas of the endometrium are detected that are suspicious for malignancy, a targeted biopsy of these foci is performed and the operation is postponed until the results of the histological examination are received.

Initially, polyps or myomatous nodes (if any) are excised with a loop electrode. The removed tissue must be sent separately for histological examination. After this, the actual ablation (resection) of the endometrium begins.

For EC, one of the following methods is used.

1. Endometrial ablation. A spherical or cylindrical electrode is used to make ironing (stroking) movements in opposite directions, current power 75 W, coagulation mode.
2. Endometrial resection with a loop electrode. The endometrium is cut in the form of shavings over the entire surface from top to bottom, current power 80-120 W, cutting mode.
3. Combined method. Resection of the endometrium of the posterior, anterior walls and fundus of the uterus is performed with a loop to a depth of 3-4 mm. Thinner areas of the uterine wall (areas of the tubal angles of the uterus and lateral walls) are not resected, and if they are, then with a small loop. The resected pieces of tissue are removed from the uterine cavity. Then, having changed the electrode to a spherical or cylindrical one, and the current power in the coagulation mode - in accordance with the size of the electrode (the smaller the electrode, the lower the current power), coagulation of the area of the uterine angles, lateral walls and bleeding vessels is performed.

At the end of the operation, the intrauterine pressure is slowly reduced; if any remaining bleeding vessels are identified, they are coagulated.

Surgical technique. With any of these methods, it is better to start from the fundus of the uterus and the area of the tubal angles. These are the most inconvenient areas, so it is better to resect them before pieces of removed tissue block the view.

Make scooping movements along the fundus and small shaving movements around the mouths of the fallopian tubes until the myometrium becomes visible. It is important to constantly remember the different thickness of the myometrium in different areas of the uterus to minimize the risk of perforation or bleeding. Manipulations in the uterine cavity must be carried out so that the electrode is constantly in the field of vision. In the area of the fundus of the uterus and the mouths of the fallopian tubes, it is better to work with a ball electrode to prevent complications (especially for novice surgeons).

After treating the uterine fundus and the area of the fallopian tube orifices, the operation is performed on the posterior wall of the uterus, since the resected pieces of tissue descend to the cervical canal and the posterior wall, impairing its visibility. Therefore, the posterior wall must be treated before the visibility deteriorates.

By moving the loop electrode towards the surgeon, the endometrium is resected from the entire posterior wall, then from the anterior wall. Resection of the endometrium to the visualization of circular muscle fibers is sufficient in the case of thinned endometrium - this is a depth of 2-3 mm. Deeper resection is not recommended due to the risk of injury to large vessels with the risk of bleeding and fluid overload of the vascular bed.

The side walls must be treated carefully and not too deeply, as large vascular bundles can be damaged. It is safer to treat these areas with a ball electrode. During the operation and at its end, the removed pieces of tissue are removed from the uterine cavity with forceps or a small curette; this must be done very carefully to avoid perforation of the uterus.

Another technique can be used, in which a complete resection of the endometrium is performed along its entire length (from the bottom to the cervix), without moving the cutting loop in the body of the resectoscope, but slowly removing the resectoscope itself from the uterine cavity. This procedure produces long tissue fragments that obscure the view, and they must be removed from the uterine cavity after each cut.

The advantage of this technique is that the uterine cavity is always free of resected tissue.

The disadvantage is that the resectoscope must be removed each time, which prolongs the operation and bleeding.

With any of the methods, endometrial resection must be stopped 1 cm before reaching the internal os to avoid cervical canal atresia.

Special attention should be paid to patients with a scar in the lower segment of the uterus after a cesarean section during endometrial resection. The wall in this area may be thinned, so the resection should be extremely shallow or superficial coagulation with a ball electrode should be performed.

In case of increased vascular bleeding, in order not to increase excessive pressure in the uterine cavity, it is advisable to periodically inject myometrium-contracting drugs into the cervix in small doses during the operation. Some doctors recommend diluting 2 ml of oxytocin in 10 ml of physiological solution for this purpose, and then injecting this solution into the cervix as needed, 1-2 ml at a time.

Endometrial laser ablation technique

During the operation, the patient and the surgeon must wear special glasses. First, a general examination of the uterine cavity is performed with an assessment of the state of the endometrium, the relief of the uterine walls, the size of the uterine cavity, and the presence of any pathological inclusions. Then the laser light guide is passed through the surgical channel of the hysteroscope.

There are two methods of laser exposure: contact and non-contact.

Contact technique. The laser tip is applied to the surface of the endometrium in the area of the mouths of the fallopian tubes, the laser is activated by pressing the pedal and the light guide is pulled along the surface of the endometrium in the direction of the cervix. In this case, the right hand constantly presses and pulls the light guide, and the left hand holds the hysteroscope. It is important to remember that the emitting end of the light guide must always be in the center of the field of view and in contact with the wall of the uterus (it illuminates with red light and is clearly visible). In this case, parallel grooves of a yellowish-brown color are formed. Usually, such grooves are first created around the mouths of the fallopian tubes, then on the anterior, lateral and (last of all) posterior walls of the uterus, until the entire uterine cavity turns into a grooved surface of a yellowish-brown color. The inner surface of the uterus is treated up to the level of the internal os if amenorrhea is expected to occur, and if not, then the laser beam is stopped at a distance of 8-10 mm from the internal os.

During vaporization, many gas bubbles and small fragments of the endometrium are formed, which impair visibility. In such a situation, it is necessary to wait until all of them are washed away by the flow of liquid and the visibility improves.

With this method, due to the small size of the emitting end of the laser light guide, the operation is time-consuming, which is considered its disadvantage.

Non-contact technique. The emitting end of the laser light guide passes over the surface of the uterine wall as close as possible without touching. In this case, it is necessary to try to direct the light guide perpendicular to the surface of the uterine wall. The sequence of treating the uterine walls is the same as in the contact technique. When exposed to laser energy, the endometrium turns white and swells, as in coagulation. These changes are less pronounced than in the contact technique. The uterine cavity is small, so it is quite difficult to bring the laser light guide perpendicular to the surface, especially in the area of the lower segment of the uterus. In this regard, a combination of two techniques is often used: contact and non-contact.

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