Resection (ablation) of the endometrium

Resection (ablation) of the endometrium

Uterine bleeding (menorrhagia and metrorrhagia), recurrent and leading to anemia, are often an indication for the removal of the uterus. Hormonal therapy does not always give a positive effect, and it is contraindicated for some women. Over the years, researchers have searched for various methods of treating uterine bleeding to avoid hysterectomy. The ablation of the endometrium was first proposed by Bardenheuer in 1937. Its essence consists in removing the entire thickness of the endometrium and the surface part of the myometrium. To achieve this, different campaigns were proposed in different years. Chemical and physical methods were originally developed. Thus, in 1947 Rongy reported on the introduction of radium into the uterine cavity. Droegmuller et al. In 1971, cryodestruction was used to destroy the endometrium. Later this idea was developed and improved in the works of V.N. Zaporozhana and co-authors. (1982, 1996), etc. Shenker and Polishuk (1973) injected chemicals into the uterine cavity with the aim of destroying the endometrium and infecting the uterine cavity. Attempts were made to introduce hot water into the uterine cavity, but this technique was not used because of thermal complications.

In 1981, Goldrath et al. For the first time, the endometrial photovaporization of the endometrium with an Nd-YAG laser was carried out by a contact technique consisting in the destruction of all endometrium leading to secondary amenorrhea. Since that time, the number of papers on the ablation of the endometrium has increased rapidly.

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

Subsequently, with the introduction of a hysteroresectoscope, interest in surgical hysteroscopy again increased significantly, including in terms of its use for resection of the endometrium. For the first time, it was proposed to use a hysteroresectoscope for resection of the endometrium of De Cherney and Polan in 1983. Improvement of endoscopic equipment, especially in the last 5-10 years (high-frequency voltage generator, set of various electrodes, apparatus for constant fluid supply with constant pressure and simultaneous suction of fluid) to a wide distribution of electroresection of the endometrium.

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

However, the search for new techniques continues. So, in 1990 Phipps et al. Suggested the use of radio-frequency electromagnetic energy for ablation of the endometrium. This method is based on the heating of the endometrium (including the basal layer) by a special conductor inserted into the uterine cavity. It is a disposable conductor with a plastic balloon with 12 plate-shaped electrodes (VALLEYLAB VESTA DUB Treatment System) at its tip.

It is known that at a temperature above 43 ° C, depending on the duration of exposure, the tissues of the human body are subject to irreversible changes as a result of protein denaturation and cell damage. The VESTA guide is inserted into the uterine cavity and air is compressed until the electrodes close to the surface of the uterine wall, then the electric power supply device is turned on. Endometrium is heated to 75 ° C, the time of therapeutic action is 4 minutes with full contact of the plates of the electrodes with the surface of the walls of the uterus. This technique does not require the use of hysteroscopy. According to research, the effectiveness of the technique is quite high, but it has not yet found wide application, and the remote results of such treatment are unknown.

In 1995, Loftier proposed a technique for ablation of the endometrium using a heating element inside a latex balloon. This balloon is placed in the uterine cavity at the tip of the applicator [Cavaterm (Wallsten MEDICAL)]. After the balloon is inserted into the uterine cavity, glycerol is injected into it, then the heating element is turned on, which causes the glycerin to be heated in the balloon, and the temperature on the surface of the balloon must be 75 ° C. In the author's opinion, such a technique is indicated for inoperable uterine cancer or perforation of the uterus, 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 time of application, necessary for its creation, is 6-12 minutes. A number of authors estimate the effectiveness of this technique in 90%.

Until now, gynecologists are not clear about the terminology: what is considered ablation of the endometrium and when to use the term "endometrial resection". Ablation of the endometrium - destruction of the entire thickness of the endometrium - can be laser and electrosurgical. In this operation, it is impossible to take tissue for histological examination. Resection of the endometrium - excision of the entire thickness of the endometrium - can only be electrosurgical: a cutting loop excises the entire mucosa in the form of shavings. With this type of surgery, it is possible to conduct a histological examination of the excised tissue.

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

Until now, there are still no clear indications for ablation or resection of the endometrium. At the same time, most endoscopic surgeons believe that indications for these surgical interventions include the following conditions:

1. Recurrent, profuse, prolonged and frequent uterine bleeding with ineffectiveness of conservative methods of therapy and lack of data on malignant pathology of internal genitalia in patients older than 35 years.
2. Recurrent hyperplastic endometrial processes in patients in pre- and postmenopausal women.
3. Proliferative processes of the endometrium in postmenopause if hormonal therapy is not possible.

Some doctors believe that with recurrent endometrial hyperplastic processes during the postmenopause, ablation (resection) of the endometrium should be combined with laparoscopic adnexectomy, as almost all patients of this group have pathological processes in one or both ovaries (more often hormone secreting structures).

Some endoscopists recommend the ablation of the endometrium with algodismorrhea, premenstrual syndrome and bleeding caused by hormone replacement therapy. However, this issue is still being debated.

When deciding whether to carry out ablation (resection) of the endometrium, in addition to a general clinical examination, other causes of uterine bleeding should be excluded. Therefore, the number of mandatory studies includes examination of the thyroid gland, hormonal status, radiography of the skull (Turkish saddle). The examination plan also includes a cytological examination of smears taken from the cervical mucosa, colposcopy and ultrasound of the pelvic organs by vaginal and abdominal sensors giving additional information about the size of the uterus, the thickness of the endometrium, the presence and location of myomatous nodes, their size and ovarian status. With a large size 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. The woman's unwillingness to maintain reproductive function.
2. Refusal from hysterectomy (desire to save the uterus) or the danger of its implementation by an open method.
3. The size of the uterus is no more than 10-12 weeks gestation.

Contraindications. The presence of fibroids is not considered a contraindication to ablation (resection) of the endometrium, provided that none of the nodes is more than 4-5 cm. Otherwise, the operation is contraindicated. Contra-indication of uterine prolapse is also contraindicated.

Ablation (resection) of the endometrium does not guarantee amenorrhea and sterilization; this patient must be warned.

Preliminary conducted hysteroscopy to assess the state of the uterine cavity, its size and contours with a histological examination of the uterine mucosa and cervical canal to exclude atypical changes in them. Women with established atypical changes in the endometrium and malignant damage to the internal genitalia should not be subjected to ablation (resection) of the endometrium.

Preparation of the endometrium. It is proved that the Nd-YAG laser beam and electric energy from the electrosurgical loop and the ball electrode destroy tissues to a depth of 4-6 mm. At the same time, even with a normal menstrual cycle, the thickness of the endometrium varies from 1 mm in the early phase of proliferation to 10-18 mm in the phase of secretion. Therefore, to obtain optimal results for ablation (resection) of the endometrium, its thickness should be less than 4 mm. For this, the operation should be performed in the early phase of proliferation, which is not always convenient for both the patient and the doctor.

Some authors propose to perform mechanical or vacuum curettage of the uterus immediately before the operation, considering it an effective alternative to drug suppression of the endometrium. The procedure becomes cheaper and more affordable, it avoids the numerous undesirable side effects of hormone therapy. In addition, the operation can be performed independently of the day of the menstrual cycle and enables the histological examination of the endometrium immediately before its ablation.

However, many surgeons believe that curettage gives insufficient thinning of the endometrium and, therefore, prefer to prepare the endometrium with the help of hormones. With hormonal suppression of the endometrium, its ablation (resection) can be performed with the subtlest endometrium, besides hormonal preparation worsens the blood supply to the uterus and reduces the size of its cavity. This reduces the operation time, 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 ablation of the endometrium (laser or electrosurgical) is planned and at a uterus size of more than 7-8 weeks of pregnancy. It is not necessary to carry out hormonal preparation if a resection of the endometrium with loop electrodes is planned.

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

Important organizational issues (especially for a beginner endoscopist): a set of necessary equipment, liquid media for stretching the uterine cavity in sufficient quantities, the correct choice of the 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 the expansion of the uterine cavity and a system for their supply under constant pressure with simultaneous suction (endomat).
4. Light source, preferably xenon.
5. Camcorder 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. Great importance for the safety, accuracy and correctness of the operation has the use of a video monitor and an intense light source.

Expanding environment. Most endoscopists prefer to perform ablation (resection) of the endometrium with liquid hysteroscopy, since the fluid provides a clear overview, while it is easy to control the course of the operation. Only Gallinat recommends the use of CO ₂ as a dilatation of the uterine cavity in endometrial ablation.

The choice of fluid for the expansion of the uterine cavity depends on the proposed method of operation. Electrosurgical operation requires non-electrolyte solutions (1.5% glycine, 5% glucose, reopolyglucin, polyglucin, etc.), while using a laser, simple liquids such as saline, Hartmann's solution, etc. Can be used. For safety reasons, fluid and pressure in the uterine cavity, constantly monitor the amount of injected and withdrawn fluid to avoid possible complications. The pressure in the uterine cavity should be in the range of 40-100 mm Hg.

For electrosurgical resection of the endometrium, most surgeons use a 8 mm diameter cutting loop that removes tissue within a 4 mm radius with one cutting, which avoids the repeated passage of the same area. When using a smaller diameter loop (4 or 6 mm), for the optimal result, the same section has to be crossed twice, which creates a hazard during the operation. But these loops are convenient for working in hard-to-reach places (the area of the uterine 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 burn tissue 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 must be 100-110 W in cutting mode.

The ablation of the endometrium is carried out with a ball or cylindrical electrode. Its shape most closely matches the inner surface of the uterus, which allows you to quickly perform an operation with a lesser depth of damage. When using ball and cylindrical electrodes, a current of 75 W is used in the coagulation mode.

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

Joint ablation (resection) of the endometrium with laparoscopy is also advisable in the following situations:

1. Resection of large and deep myomatous nodes along with resection of the endometrium.
2. Sterilization. In this case, the sterilization is first performed, and then the ablation (resection) of the endometrium to prevent the entry of fluid through the fallopian tubes into the abdominal cavity.
3. Ablation (resection) of the endometrium in a patient with a two-legged uterus or a thick septum in the uterus.

After ablation (resection) of the endometrium (both electrosurgical and laser), complete amenorrhea does not appear in all. A woman before surgery should be warned that a good outcome is considered hypomenorrhea (a significant reduction in menstrual bleeding). According to different authors, amenorrhea is recorded in 25-60% of cases. The effect of the operation is maintained for 1-2 years in approximately 80% of the operated.

The result of the operation is influenced by the age of the patient, the size of the uterine cavity, the presence of adenomyosis. The best results were obtained in women aged 50 years and older with small uterine sizes. At present, a lot of work has been done on re-ablation of the endometrium.

Even with complete amenorrhea, the risk of becoming pregnant after the ablation of the endometrium is maintained, so patients of reproductive age are advised to sterilize before surgery. There is also the risk of an ectopic pregnancy, and in the case of uterine pregnancy, due to a deterioration in the blood supply to the uterus, there may be impairments in the development of the fetus and the placenta (for example, the risk of a true increase in the placenta increases). About these problems a woman needs to be informed.

After ablation of the endometrium, hormone replacement therapy is not contraindicated.

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

The method of electrosurgical ablation of the endometrium

The patient is located on the operating chair, as with small gynecological operations. Preliminary conduct bimanual examination to determine the position of the uterus and its magnitude. After processing the external genitalia, the cervix is fixed with bullet forceps, the cervical canal is widened by Gegar dilators to No. 9-10 (depending on the resectoscope model and the size of its outer casing). The patient is given Trendelenburg's position for intestinal distraction in the cephalic direction in order 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 in the integrity and integrity of the electrical wires, the correctness of their connection.

After this 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-sized submucosal nodes does not serve as a contraindication to surgery. If a septum is diagnosed in the uterus cavity or a bicornic uterus, the operation is not discarded, but it is carried out very carefully, by slightly changing the technique. When identifying areas of the endometrium that are suspected of malignancy, a targeted biopsy of these lesions is performed and the operation is postponed until the results of the histological examination are obtained.

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

In EC, one of the following procedures is used.

1. Ablation of the endometrium. A spherical or cylindrical electrode produces ironing (dashed) oppositely directed motions, a power of 75 W, a coagulation regime.
2. Resection of the endometrium with a loop electrode. The endometry is cut in the form of chips all over the surface from the top down, the current power is 80-120 W, the cutting mode.
3. Combined method. Carry out a resection of the endometrium of the posterior, anterior walls and the bottom of the uterus with a loop to a depth of 3-4 mm. Thinner sections of the uterine wall (areas of the uterine tube corners and side walls) do not undergo resection, and if they are subjected, a small loop. The resected tissue pieces are removed from the uterine cavity. Then, changing the electrode to ball or cylindrical, and the current in the coagulation mode - in accordance with the value of the electrode (the smaller the electrode, the lower the current power), coagulate the area of the uterine angles, lateral walls and bleeding vessels.

At the end of the operation, the intrauterine pressure is slowly lowered, and when they are detected, the remaining bleeding vessels are coagulated.

Operation technique. With any of these techniques, it is better to start from the bottom of the uterus and the area of the tube angles. These are the most uncomfortable areas, so it is better to resect them before the pieces of the removed tissue close the view.

Perform scooping movements along the bottom and small shaving movements around the mouths of the fallopian tubes until it becomes visible to the myometrium. You should always remember about the different thickness of the myometrium in different parts of the uterus to minimize the risk of perforation or bleeding to a minimum. Manipulation in the uterine cavity should be done so that the electrode is constantly in the field of vision. In the field of the uterine fundus and the ostium of the fallopian tubes, it is better to work with the use of a ball electrode to prevent complications (especially to beginning surgeons).

After treatment of the uterine fundus and the area of the uterus of the fallopian tubes, the operation is performed on the back wall of the uterus, as the resected pieces of tissue descend to the cervical canal and posterior wall, worsening its view. Therefore, it is necessary to process the back wall before the deterioration of the survey.

The movements of the loop electrode towards the surgeon resect the endometrium from the entire posterior wall, then from the anterior end. Sufficient resection of the endometrium before visualization of circular muscle fibers with a thin endometrium is 2-3 mm deep. Deeper resection is not recommended because of the risk of injury to large vessels with a risk of bleeding and fluid overload of the vascular bed.

Work with the side walls must be carefully and shallow, as it is possible to damage large vascular bundles. These areas are safer to handle with a ball electrode. In the course of the operation and at its end, the removed pieces of tissue are removed from the uterine cavity by forceps or a small curette; this should be done very carefully to avoid perforation of the uterus.

It is possible to use another technique, in which a complete resection of the endometrium is carried out along the entire length (from the bottom to the neck), without making a cutting loop of movements in the resectoscope body, and slowly removing the resectoscope from the uterine cavity. With this procedure, long fragments of tissue that interfere with the vision are formed, and they must be removed from the uterine cavity after each cutting.

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

The disadvantage is that every time you need to remove a resectoscope, which lengthens the operation and bleeding.

In any of the methods, resection of the endometrium should be stopped, not reaching 1 cm to the inner throat, to avoid atresia of the cervical canal.

Particular attention in resection of the endometrium deserves a patient with a scar in the lower segment of the uterus after cesarean section. The wall in this place can be thinned, therefore the resection should be extremely shallow or it is necessary to carry out surface coagulation with the ball electrode.

With increased bleeding of the blood vessels, in order not to increase excessive pressure in the uterine cavity, during the operation it is advisable to periodically inject the myometrial reducing preparations into the cervix of the uterus in small doses. Some doctors recommend that you dilute 2 ml of oxytocin in 10 ml of physiological saline, and then add 1-2 ml to the cervix as needed.

The method of laser ablation of the endometrium

During surgery, special glasses should be worn on the patient and the surgeon. First, a general examination of the uterine cavity with an assessment of the state of the endometrium, the relief of the walls of the uterus, the size of the uterine cavity, the presence of any pathological inclusions. The laser light guide is then passed through the operating channel of the hysteroscope.

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

Contact technique. The laser tip is applied to the endometrium surface in the area of the uterus of the fallopian tubes, the laser is activated by pressing the pedal and the light guide is pulled along the surface of the endometrium towards the cervix. With this, the right hand is constantly pressed onto the light guide and sips it, and the hysteroscope is held with the left hand. It is important to remember that the emitting end of the fiber should be constantly in the center of vision and in contact with the wall of the uterus (it illuminates in red and is clearly visible). In this case, parallel furrows are formed in a yellowish brown color. Usually, first these furrows are created around the mouths of the fallopian tubes, then on the anterior, lateral and (lastly) posterior walls of the uterus, until the entire uterine cavity turns into a furrowed surface of a yellowish brown color. Treatment of the inner surface of the uterus is made up to the level of the internal throat if an amenorrhoea is planned, and if not, then the laser beam is stopped at a distance of 8-10 mm to the inner pharynx.

During vaporization, many gas bubbles and small fragments of the endometrium are formed, which worsen the vision. In such a situation it is necessary to wait until all of them are washed away by the current of the liquid and the review does not improve.

With this technique, because of the small size of the emitting end of the laser light guide, the operation is time-consuming, which is considered a disadvantage.

Non-contact technique. The radiating end of the laser light guide passes over the surface of the uterine wall as closely 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 order of treatment of the walls of the uterus is the same as in the contact technique. When exposed to laser energy, the endometrium becomes white and swells, as in coagulation. These changes are less pronounced than with the contact technique. The uterine cavity has small dimensions, 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 connection, a combination of two methods is often used: contact and non-contact.

[1], [2], [3], [4]