Obstetrics and Gynecology - A.M. Hromova 2000

Operative Obstetrics
Operations Preparing the Birth Canal
Cervical Dilatation

Indications for mechanical dilatation of the cervix include:

1. Maternal conditions during Pregnancy requiring termination.

2. Pathological Changes in the cervix that impede its dilation:

a) cervical rigidity;

b) cicatricial strictures of the cervix;

c) vagino fixatio uteri — following this Procedure, the cervix is displaced posteriorly, and an angulation forms between the uterine body and the cervix, which prevents proper dilation of the cervical canal.

3. Complications during the dilation process: spastic stricture of the cervix, which may lead to cervical laceration.

Conditions required for these Procedures:

1. Effacement of the cervix.

2. Dilation of the os to at least 2 cm.

Digital Dilation of the Cervix

Surgical technique. After disinfecting the external genitalia with an antiseptic solution, the hand is introduced into the Vagina and two fingers are inserted into the cervix to spread the edges of the cervical canal. As dilation progresses, the third, fourth, and fifth fingers are successively introduced. Following this, corkscrew-like movements are performed to introduce the hand into the uterine cavity.

Cervical Dilation Using Hegar Dilators

Surgical technique. After disinfection of the external genitalia, the cervix is exposed using wide vaginal specula, elevated, and its margins are secured with bullet forceps. The obstetrician holds the bullet forceps in the left hand while using the right hand to introduce a uterine sound into the cervical canal. After sounding, the cervical canal is dilated using Hegar dilators (bougies).

Cervical Incisions (Dührssen's Incisions)

Surgical technique. The cervix is exposed using wide vaginal specula and elevated, with the margins secured by bullet forceps. Guided by two fingers, blunt-ended curved scissors are advanced toward the external os. One blade is inserted into the cervical canal, and the cervix is incised by no more than 1 cm at the 10, 1, 3, and 5 o'clock positions (corresponding to 10, 13, 15, and 19 hours on the clock face). Incising the cervix along the midline is contraindicated due to the risk of injuring the Urinary Bladder, uterine Arteries, or opening the extraperitoneal space should the laceration spontaneously extend under the pressure of the fetal presenting part during labor.

Metreurysis, Colpeurysis

The cervical canal can be dilated by introducing a sterile rubber balloon into the uterine cavity (in metreurysis) or into the posterior vaginal fornix (colpeurysis), followed by filling it with fluid. This stimulates reflex uterine contractions, accelerates cervical dilation, and prevents Premature Rupture of membranes. To prevent infection, the balloon should not remain in the birth canal for more than 4–6 hours.

Contraindications for metreurysis and colpeurysis include severe forms of late pre-Eclampsia, neoplasms in the cervical and vaginal regions, and the presence of an infection in the birth canal. These procedures are frequently complicated by uncoordinated or hypertonic uterine activity and can contribute to fetal malpresentation. In modern clinical practice, these procedures are rarely used.