What is Intrauterine Synechia (Adhesions)?
Intrauterine synechia (adhesions), or the so-called Asherman syndrome, consist in partial or complete fusion of the uterine cavity.
Pathogenesis during Intrauterine Synechia (Adhesions)
There are infectious, traumatic, neuro-visceral theory of intrauterine synechia. The main factor is the mechanical trauma of the basal layer of the endometrium after childbirth or abortion (wound phase), and the infection serves as a secondary factor. In terms of possible injury to the uterine mucosa, the first 4 weeks after childbirth or termination of pregnancy are considered the most dangerous.
The occurrence of intrauterine synechiae is most likely in patients with a missed abortion. After curettage of the uterus, they more often than in patients with incomplete abortion, intrauterine synechia develop, which is associated with the fact that the placental tissue residues can cause the activation of fibroblasts and the formation of collagen before endometrial regeneration. Intrauterine synechia develop in 5-40% of patients with repeated miscarriages.
Intrauterine synechia can occur after surgery on the uterus: myomectomy, metroplasty or diagnostic curettage of the uterine mucosa, conization of the cervix, as well as after endometritis. This pathology can also provoke intrauterine contraceptive.
Classification. There are several classifications of intra-uterine synechia.
On the histological structure, O. Sugimoto (1978) identifies 3 types of intrauterine synechia:
- light – synechia in the form of a film, usually consisting of basal endometrium, are easily dissected with the tip of a hysteroscope;
- medium – fibromuscular, covered with endometrium, bleed when dissected;
- heavy – connective tissue, dense synechiae, usually do not bleed when dissected, dissected with difficulty.
According to the prevalence and degree of involvement of the uterus, S. March, R. Izrael (1981) proposed the following classification:
- I degree – less than 1/4 of the uterine cavity is involved, thin adhesions, the bottom and mouth of the tubes are free;
- II degree – 1/4 to 3/4 of the uterine cavity is involved, there is no adhesion of the walls, only adhesions, the bottom and mouth of the tubes are partially closed;
- III degree – more than 3/4 of the uterine cavity is involved.
Since 1995, a classification adopted by the European Association of Endoscopic Gynecologists (ESH) has been used in Europe, highlighting 5 degrees of intrauterine synechia based on hysterography and hysteroscopy, depending on the condition and extent of synechiae, occlusion of the orifices of the fallopian tubes and the extent of damage to the endometrium:
- I degree. Thin or gentle synechia – easily destroyed by the body of the hysteroscope, the areas of the mouths of the fallopian tubes free.
- II degree. A single dense synechia – connecting separate, isolated areas of the uterus, usually seen the mouth of both fallopian tubes, can not be destroyed only by the body of the hysteroscope.
– IIa degree. Synechiae only in the area of the internal os, the upper sections of the uterus are normal.
- III degree. Multiple dense synechia – connecting separate isolated areas of the uterus, unilateral obliteration of the mouth of the fallopian tubes.
- IV degree. Extensive dense synechia with (partial) occlusion of the uterus – the mouth of both fallopian tubes partially closed.
– Va degree. Extensive scarring and fibrosis of the endometrium in combination with grade I or II – with amenorrhea or overt hypomenorrhea.
– Vb degree. Extensive scarring and fibrosis of the endometrium in combination with grade III or IV – with amenorrhea.
In the United States, the classification of the American Association for Infertility (AFS), adopted in 1988, is used. This classification is somewhat cumbersome; scores are conducted on the involvement of the uterus, type of synechiae, and changes in menstrual function.
There are 3 stages: weak (I), medium (II) and severe (III).
Scoring is conducted separately according to hysteroscopy and hysterosalpingography. Stage I correspond to 1-4 points, Stage II – 5-8 points, Stage III – 9-12 points.
Symptoms of Intrauterine Synechia (Adhesions)
Depending on the degree of overgrowth of the uterus, intrauterine synechia manifest as hypomenstrual syndrome or amenorrhea and, as a result, sterility and miscarriage. In the case of a fusion of the lower part of the uterine cavity with a normal functioning endometrium in the upper part of the uterine cavity, a hematometer may develop. Significant fusion of the uterine cavity and the lack of a normally functioning endometrium lead to the difficulty of implantation of the ovum. Even mild intrauterine synechiae are one of the reasons for the ineffectiveness of in vitro fertilization.
1/3 of women with intrauterine synechiae have spontaneous miscarriages, 1/3 have premature births and 1/3 have pathology of the placenta (tight attachment, presentation). Thus, pregnancy in patients with intrauterine synechia should be considered as a high risk, with a high potential for complications of pregnancy, childbirth and the postpartum period.
Diagnosis of Intrauterine Synechia (Adhesions)
To date, there is no uniform algorithm for examining patients with suspected intrauterine synechia. According to many researchers, the examination of patients with suspected intrauterine synechia should begin with diagnostic hysteroscopy and in case of doubt carry out hysterosalpingography.
Hysterosalpingography. The X-ray picture of intra-intra-synechiae depends on the nature and extent of synechiae. Usually they manifest themselves in the form of single or multiple filling defects, irregular, lacuniform shapes and various sizes. Dense multiple synechiae can divide the uterus into multiple chambers of different sizes, interconnected by small ducts. This configuration of the uterus is not determined by hysteroscopy, which can reveal only the first few centimeters of the lower segment of the uterus. With hysterography, the fluid contrast will find its way through these complex labyrinths and non-obliterated spaces. However, hysterosalpingography gives a lot of false positive results due to scraps of the endometrium, mucus, curvature of the uterus.
Ultrasound. The possibilities of echography in the diagnosis of intrauterine synechiae are limited. In some cases, irregular contours of the endometrium are visualized, with an hematometer, an anechoic mass is formed that fills the uterine cavity. Hydrosonography allows to identify single intrauterine fusion in those observations when there is no complete obstruction in the lower part of the uterus.
Hysteroscopy has now become the main diagnostic method for intrauterine synechia. During hysteroscopy, the synechiae are defined as whitish avascular cords of various lengths, densities and lengths between the walls of the uterus, often reducing its cavity, and sometimes completely obliterating it. Synechiae can also be located in the cervical canal, causing it to fade and preventing entry into the uterine cavity. Gentle synechias look like strands of a pale pink color, in the form of cobwebs, sometimes there are vessels passing through them.
More dense synechias are defined as dense whitish yarns, which are usually located on the side walls and rarely in the center of the uterus. Multiple transverse synechiae cause partial fusion of the uterine cavity with cavities of various sizes in the form of depressions (holes). Sometimes these holes are mistaken for the mouth of the fallopian tubes.
Treatment of Intrauterine Synechia (Adhesions)
Currently, the only treatment for intrauterine synechiae is to dissect it under direct visual control with a hysteroscope without injuring the remaining endometrium to restore the normal menstrual cycle and fertility. The nature of the operation, its effectiveness and long-term results depend on the type of intrauterine synechia and the degree of occlusion of the uterus.
Centrally located synechiae can be divided bluntly with the help of a hysteroscope housing. Endoscopic scissors and forceps, a hysteroresectoscope with an electrocautery electrode are also used according to the contact technique.
Gentle, weak synechiae (endometrial) are easy to destroy with a hysteroscope body or cut with scissors and forceps. More dense synechias are dissected with scissors gradually, step by step, until the normal shape of the uterus cavity is restored. When dissecting dense, fibrous synechiae, it is better to use a hysteroresectoscope with an electrode, an “electrocautery” or a laser conductor. To prevent possible perforation of the uterus, the operation is performed under ultrasound guidance with a small occlusion of the uterus and under laparoscopic control with significant occlusion.
Despite the high efficacy of hysteroscopic adhesiolysis of intrauterine synechiae, a relapse of the disease is not excluded, especially with widespread, dense synechiae (up to 60%) and in patients with tuberculous lesion of the uterus. To prevent recurrence of intrauterine adhesions, almost all surgeons suggest introducing various devices (Foley catheter, IUD) with subsequent hormonal therapy (estrogen-gestagens in high doses) into the uterine cavity in order to restore the endometrium within 3-6 months. Preferably the introduction of the IUD type Lipps loop for a period of at least 1 month.
Forecast. Transervical dissection of intrauterine synechia under the control of a hysteroscope is highly effective. The effectiveness of such an operation depends on the prevalence and extent of intrauterine adhesions: the more overgrown the uterus, the less effective the operation. The worst predictions in terms of menstrual and reproductive function recovery and disease recurrence are during intrauterine synechia of tuberculosis etiology. Restoration of menstrual function and the creation of a normal uterine cavity can be achieved in 79-90%, pregnancy occurs in 35-75%, and pathology of placental attachment occurs in 5-31% of cases.
Pregnant women after dissection of common intrauterine synechiae are at risk. In addition to frequent miscarriage, postpartum bleeding is observed.
Prevention of Intrauterine Synechia (Adhesions)
It is necessary to remember about the possibility of intrauterine synechia in patients with a complicated course of the early postpartum and post-abortion periods. In the event of menstrual disorders in such women, hysteroscopy should be carried out as early as possible for early diagnosis and destruction of synechia. In patients with suspected delayed residues of the ovum or placenta, it is advisable to carry out not just curettage of the uterus mucosa, but hysteroscopy to clarify the location of the pathological focus and its targeted removal without injury to the normal endometrium.