[Gynecological hysteroscopy] Uterine septum resection

What are the indications for hysteroscopic septum resection?

The embryogenesis of the uterus originates from the Mullerian duct. At 4-6 weeks of embryonic development, the tail ends of the bilateral mesonephric ducts fuse, and the lower ends form the uterus and vagina. At 19-20 weeks of embryonic development, the bilateral mesonephric ducts have completely fused, and the septum in the middle is absorbed and degenerated, forming a normal uterine cavity.

Uterine septum is a female reproductive tract malformation caused by absorption disorders after the fusion of bilateral paramesonephric ducts due to some reasons during the development of uterine embryos. The incidence rate is 0.009%~12.000%, which is the most common uterine malformation, accounting for about 80%. Uterine septum can cause infertility, recurrent miscarriage, premature birth, and the probability of premature rupture of membranes, placenta previa, and placental abruption is relatively high.

According to the shape of the septum and the attachment position of the septum tip, it is divided into complete uterine septum and partial uterine septum. Complete uterine septum starts from the uterine fundus and ends at the internal or external cervical os, accounting for 14% to 17% of uterine septum. The septum tip ends at the external cervical os, usually looking like a double cervix. 20% to 25% of uterine septum is combined with vaginal septum. Partial uterine septum separates part of the uterus, and the tip of the uterine septum ends in the uterine cavity. Those with no history of adverse pregnancy and childbirth can try to get pregnant first.

Patients who desire to have children and have a history of infertility or adverse pregnancy and delivery such as recurrent miscarriage, premature birth, abnormal fetal position, intrauterine fetal death, etc., all have surgical indications and can undergo hysteroscopic uterine septum resection (TCRS) under ultrasound or laparoscopic monitoring. Zabak et al. believe that patients who have two or more spontaneous miscarriages due to the presence of uterine septum, infertility without other explanations, and infertile patients who plan to undergo assisted reproduction all have surgical indications.

Septate uterus: after the bilateral paramesonephric ducts fuse, a certain process of septum absorption is blocked, forming uterus of varying degrees, which can be divided into complete uterus and incomplete uterus. It can manifest as recurrent miscarriage, excessive menstrual flow, dysmenorrhea, etc. Generally, surgical treatment can restore the normal anatomical morphology and function of the uterus to a certain extent.

Common symptoms:

Clinically, it mainly affects the pregnancy outcomes of women in their childbearing period, including recurrent miscarriage, premature birth, premature rupture of membranes, etc., among which recurrent miscarriage is the most common.

Main cause: after the fusion of the two paramesonephric ducts, a certain process of septal absorption is blocked

Clinical classification

Depending on the position of the end of the septum in the uterine cavity, it can be divided into complete septate uterus and incomplete septate uterus.

1. Complete septate uterus: The end of the septum reaches or exceeds the internal cervical os, and the appearance is like a double cervix.

2. Incomplete septate uterus: The end of the septum ends above the internal os.

Treatment

The main surgical indication for uterine septate is a history of adverse obstetrics, not the discovery of septate uterus. There is still controversy about when to perform uterine septate correction surgery. Some scholars suggest that surgery should only be performed in cases with adverse reproductive history, while others recommend preventive hysteroscopic metroplasty to prevent adverse obstetric outcomes related to malformation.

The main indication for surgery in patients with a septate uterus is recurrent miscarriage, as surgery has been observed to improve reproductive outcomes in such patients. The value of metroplasty in patients with a septate uterus and infertility remains controversial. Mollo et al reported in a prospective study that patients had an increased pregnancy rate after correction of a septate uterus, and today it is accepted that hysteroscopic metroplasty improves pregnancy rates in patients with primary infertility.

De Angelis demonstrated the benefits of metroplasty before fertility treatment for patients who will undergo assisted reproduction and concluded that hysteroscopic metroplasty is recommended for all patients with uterus septate before IVF to improve the success rate.

The surgical approach to uterus septate has evolved from the laparotomy approach of Tompkins or Jones to the current hysteroscopic approach. In 1974, Edstrom first described the surgical method of removing the uterine septum under endoscopic guidance, which is the predecessor of today's metroplasty.

Hysteroscopic metroplasty includes two methods: transverse incision of the uterine septum and actual removal of the uterine septum. The septal incision should be performed in the middle of the septum, equidistant from the anterior and posterior walls of the uterus. The fallopian tube opening is very helpful in maintaining the correct plane and direction and avoiding damage to the normal uterine myometrium.

We conclude that removal of the uterine septum significantly reduces miscarriage and preterm birth rates and improves fertility in women with a septate uterus and unexplained infertility. Hysteroscopic metroplasty is an effective and safe treatment with a low complication rate when performed by an expert after an accurate diagnosis.

Surgical process

1. The patient is placed in lithotomy position, routine disinfection and draping are performed, gynecological examination is performed to understand the position and size of the uterus, the cervix is  exposed and clamped, and the cervical canal is disinfected.

2. Use diagnostic hysteroscopy to examine the cervical canal and uterine cavity to understand the type of uterine septum, the depth and width of the septum, etc. After the hysteroscopy confirms the diagnosis, withdraw the hysteroscope.

3. Explore the uterus and dilate the cervical canal (generally dilated to No. 10, depending on the outer diameter of the resectoscope used).

4. Insert the hysteroscopy with the needle electrode installed under direct vision.

5. Under hysteroscopy, use a needle electrode to remove the septum from the lower edge of the septum from the right side to the left side (or from the left side to the right side, depending on the surgeon's surgical habits and experience) on the line connecting the fallopian tube openings. Gradually remove the septum further toward the uterine fundus until the septum is completely removed.

6. After the septum has been removed under hysteroscopy, electrocoagulate obvious bleeding points (Figure 6), check for jetting bleeding points, withdraw the hysteroscopic resection mirror, and end the operation.

Special Cases

Special Case 1:

When the septum extends down to the cervix, it is first divided with cold shears or with a cutting electrosurgical probe. The resection begins at the level of the cervix and extends from the external ostium toward the uterus. The division of the uterine septum is continued, carefully preserving the plane of the tubal ostium.

Special Case 2:

When the uterine septum is wide, it is necessary to stop the bleeding as soon as possible. Then, the procedure is performed in the second operation 2 months after the second stage to complete the procedure.

Special Case 3:

The operation steps begin with dividing the vaginal septum using monopolar electrosurgery, excising the septum until the anterior and posterior fornix, and suturing the anterior and posterior surfaces of the vagina with interrupted absorbable sutures. Then the procedure is continued for the septate uterus.

End of surgery

At the end of the surgery, it is best to leave less than 1 cm from the fundus to avoid weakening the basal muscles. At the end, the tubal opening is visible under the same field of view as the hysteroscope. This is important because the risk of perforation increases if the resection is performed too far. Some surgeons recommend a follow-up ultrasound to ensure there is no perforation.

Immediately after surgery:

If the inflow-outflow assessment is above 500 mL, a chemical test must be performed.

After 2 months, a follow-up diagnostic hysteroscopy is performed:

Check for possible adhesions. These new, thinner adhesions are usually easily removed by the tip of the hysteroscope during the diagnostic procedure.

If the remaining fundus is greater than 1 cm, a second procedure is indicated.

The only criterion for success is a subsequent pregnancy resulting in a spontaneously viable fetus.