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Cervical Cerclage

Technique

Approach

Cerclage is usually done transvaginally as either a McDonald
or a Shiradkor
procedure. When these 2 procedures are unsuccessful or difficult to perform, the transabdominal cerclage procedure is done.

McDonald’s Cerclage

The McDonald’s cerclage is performed using a permanent suture. It was originally described as follows: “The bladder having been emptied, the cervix is exposed and grasped by Allis’ or Babcock forceps. A purse string suture of No. 4 Mersilk on a Mayo needle is inserted around the exo-cervix as high as possible to approximate to the level of the internal os. This is at the junction of the rugose vagina and smooth cervix. Five or six bites with the needle are made, with special attention to the stitches behind the cervix. These are difficult to insert and must be deep…The stitch is pulled tight enough to close the internal os, the knot being made in front of the cervix and the end left long enough to facilitate subsequent division.”

The author usually uses a Prolene #1 suture placed in a purse string fashion. Under regional anesthesia, the cervix is visualized by placing a long weighted speculum posteriorly, and curved or right angle retractors anteriorly and laterally as needed. With patient in stirrups and in the lithotomy position, the author uses an Allis to grasp the cervix as high in the vagina as possible, first at the 10 o’clock position. This Allis is used to retract cervical tissue inferiorly and laterally, to ensure that only cervical tissue is included in the bite and that the cervical canal is not violated or entered. The suture is placed immediately below the Allis clamp, hugging the clamp as the curved needle is rotated through. This maneuver is then repeated at the 8, 4, and 2 o’clock positions.

A surgeon’s knot is placed, the knot is cinched down tightly, and several additional throws are placed (see the image below). The ends are cut long to allow identification at term and facilitate removal. Several different modifications have been described, including placement of a second suture above the first if the surgeon feels the cervical length (which should be more than 10 mm) below the first suture is inadequate.

Suture placement.

Suture placement.

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Shiradkor Technique

The original technique was described as follows:

I. A strip of fascia lata 1/4 inch wide and 4 1/2 inches long, is removed from the outer side of the thigh, and each end of this strip is transfixed with a linen suture.

2. The cervix is pulled down, a transverse incision is made above the cervix as in anterior colporrhaphy, and the bladder is pushed well up above the internal os.

3. The cervix is then pulled forward, toward the symphysis pubis, and a vertical incision is made in the posterior vaginal wall, again at and above the internal os, going only through the vaginal wall.

4. Through the right and left corner of the anterior incision an aneurysm needle is passed between the cervix and the vaginal wall until its eye comes out of the posterior incision.

5. The linen attached to each end of the fascia is passed through the eye of the aneurysm needle, and the right end of the fascia is pulled retrovaginally forward into the anterior incision. The same thing is done from the left side.

6. The two ends of the strip cross each other in front of the cervix and are tightened to close the internal os. The operator’s left index finger in the internal os will indicate how much to pull on the strips. The assistant should be holding one end of the strip with an artery forceps.

7. The two ends are stitched together by a number of stitches that take a bite of the muscle fibers of the lowest part of the lower uterine segment, using a small curved needle and fine linen.

8. Extra portions of the fascia are cut out, and the anterior and posterior incisions are closed with chromic catgut No. 0.

Many modifications have been made, but in general the Shiradkor technique involves dissection of the vaginal mucosa and retraction of the bladder and rectum to expose the cervix at the level of the internal os. Usually, a curved Allis clamp is used to grasp the lateral edges of the anterior and posterior aspects of the transverse incisions and some paracervical tissue. The suture is then placed using a 5 mm tape suture with a double blunt needle at each end. The suture is placed anteriorly and tied posteriorly or placed posteriorly and tied anteriorly. If the patient is to be delivered by cesarean, the suture can be buried under the vaginal mucosa, which is then re-approximated using absorbable suture, or the knot can be left exposed for easy removal if vaginal delivery is planned.

Caspi et al described a modification using a single transverse incision in the anterior fornix.
A monofilament suture is passed on each side, under the mucosa at the level of the internal os, from the anterior incision to exit through the mucosa of the posterior cervix, and is then tied. The procedure was compared with the modified technique of Shirodkar in a randomized fashion in 90 subjects with previous failed McDonald procedure or with cervical anatomy felt to be unfavorable for McDonald cerclage placement.
Similar pregnancy outcomes were reported. The investigators believed that this modification has the advantages of simplicity, ease of removal, and lower incidence of severe vaginal discharge.

A retrospective study by Kindinger et al that included 678 women who received cervical cerclage reported that compared to monofilament suture, braided cerclage was associated with increased intrauterine death (15% vs 5%; P = 0.0001) and preterm birth (28% vs 17%; P = 0.0006). A prospective, longitudinal, follow-up study of the vaginal microbiome in women at risk of preterm birth because of short cervical length (≤25 mm) also found that braided suture induced a persistent shift toward vaginal microbiome dysbiosis. Although these results are preliminary and we need additional studies to confirm these findings, it appears that monofilament synthetic non-absorbable sutures like Prolene may be advantageous to braided sutures in the setting of cervical cerclage in pregnant women.

Authors’ preference

The patient is placed in the lithotomy position in stirrups. The vagina is prepped with Betadine. A long, weighted speculum is placed in the posterior vagina. The posterior lip of the cervix is grasped with ring forceps or tenacula. Care should be exercised not to lacerate the cervix.

Since bleeding from the anterior mucosal incision often obscures the operator’s view of the posterior cervix, the posterior mucosal incision is made first. A small (2-cm) vertical incision is begun approximately 2.5 cm above the external os and carried proximally. The plane between the vaginal mucosa and the cervix is entered and developed using blunt dissection.

The cervicovesical reflection is identified. The anterior mucosal incision, approximately 2 cm long is made transversely at the cervicovesical reflection, and blunt dissection is used to develop the appropriate plane approaching as close to the internal os as possible.

A curved Allis clamp is used to bring the mucosa and paracervical tissue laterally. One blade of the clamp is inserted in the anterior incision and the other in the posterior incision. As the clamp is closed, the tissue is drawn away from the substance of the cervix.

Five mm Mersilene tape on a curved needle is used. It is placed similarly to what is described above for the McDonald’s procedure. The needle is rotated against the clamp hugging the tip of the clamp opposite the curvature of the cervix. This ensures avoiding the cervical canal and membranes. It is best to enter posteriorly first so the knot ends up posterior and not anteriorly against the bladder. The exact procedure is performed on the opposite side driving the needle in the anterior to posterior direction.

A small permanent suture such as 3-0 Prolene can then be used to anchor the suture anteriorly at the level of internal os, or an absorbable suture can be used. Placing the permanent suture to anchor the tape anteriorly through the vaginal mucosa allows easy removal if the cerclage is to be removed later.

The cerclage can then be tied posteriorly. The ends are left long and through the posterior incision. The edges of the posterior and anterior incision are approximated by interrupted 3-0 chromic.

The advantage of Shiradkor is placement close to the level of the internal os and that most of the suture is buried (see image below); the disadvantages include bleeding when it is performed during pregnancy and difficulty in removal at term.

Cervical cerclage.

Cervical cerclage.

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Abdominal Cerclage

Some patients manifest severe cervical injures, and others have apparent congenital absence of the cervix, rendering Shirodkar or McDonald cerclage technically difficult or impossible. Benson and Durfee described an abdominal approach to cerclage, a procedure that was applied to congenitally short or surgically amputated cervices.

Novy popularized this procedure and added the indications of “wide or extensive cervical conization, cervico-vaginal fistulas following abortion, or a previously failed vaginal approach to cervical cerclage.”
In addition, Novy suggested using this procedure in pregnant patients with cervical effacement that precluded high placement of a vaginal cerclage. Novy later reported on 16 patients treated with transabdominal cerclage during a 14 year interval, including 22 pregnancies, 21 of which resulted in living children.

Guidelines for patient selection include the following:

Previous failed vaginal cerclage with scarring or lacerations rendering vaginal cerclage technically very difficult or impossible

Absent or very hypoplastic cervix with history of pregnancy loss fitting classical description of cervical insufficiency

Advantages to abdominal cerclage include the following:

It can be performed in patients who cannot be treated successfully with vaginal cerclage.

The cerclage can be placed higher on the cervix, at the level of the internal os.

The main disadvantages of abdominal cerclage are:

The patient must undergo two laparotomies, one for the cerclage placement and another for the cesarean delivery.

The pregnancy that results in fetal death or preterm labor prior to viability after abdominal cerclage will need a hysterotomy even though no living child will result.

This the procedure is reserved for highly selected cases. The following approach to abdominal cerclage is based upon Novy’s descriptions:

The procedure is planned at the end of the first trimester or the early second trimester, after fetal viability has been documented and initial ultrasound evaluation of the pregnancy has ruled out any major congenital malformation. It is important to wait until the risk of spontaneous first trimester abortion has passed, so that a second laparotomy to remove a nonviable pregnancy is not necessary.

Either regional or general anesthesia can be employed. A catheter is placed in the bladder. Both Pfannenstiel and vertical abdominal incisions have been advocated, but transverse incision is adequate in most cases.

The peritoneal cavity is opened, and the bladder flap is incised transversely for approximately 5 cm at its reflection on the uterus, just above the level of internal cervical os. The bladder flap is advanced downward bluntly for about 5 cm

The uterus is wrapped in a laparotomy pad moistened with warm saline. The uterus is elevated through the abdominal incision, putting the cervix on traction. The uterine artery on each side is identified and retracted laterally. The avascular space between the ascending and descending branch is visualized and then this space is further expanded by gentle lateral retraction.

A 5-mm Mersilene tape on a needle is then placed through the avascular space from anterior to posterior.

The same process is repeated on the other side of the uterus except that the needle carrying the Mersilene tape is now passed from posterior to anterior so that the knot can be placed anteriorly.

Care must be taken to insure that the Mersilene tape is flat all the way around and not twisted. A square knot is placed anterior to the internal os, compressing the cervical tissue but not too tightly. The free ends of the tape are secured with 3-0 Prolene sutures placed approximately 1 to 2 cm distal to the knot. The remaining free ends are then cut away . The posterior portion of the band passes around the isthmus of the uterus at about the level of insertion of the uterosacral ligaments and is easily palpable and visible from behind as the uterus is drawn into the incision. Later it will become encased in scar tissue.

The peritoneal cavity, and abdominal incision are closed.

Emergency Cerclage

All 3 of the above procedures for cervical insufficiency are best performed prior to cervical dilation and effacement. However, many patients do not have the classic history that indicates prophylactic cerclage in the late first or early second trimester. Such patients are managed expectantly, with cerclage reserved for those who manifest cervical change demonstrated clinically or by ultrasound.

Therefore, many cerclage procedures are performed emergently rather than prophylactically. The most important step in performing emergency cerclage is making the diagnosis. Other causes of premature cervical dilation must be ruled out, specifically preterm labor, premature rupture of membranes and chorioamnionitis.

If regular uterine contractions are present, tocolysis may be considered. Abruptio placentae should be part of the differential diagnosis, especially with bleeding and is considered a relative contraindication to tocolysis and probably an absolute contraindication to cerclage.

In patient with contractions, emergency cerclage should only be considered if uterine contractions can be successfully inhibited and the clinician is convinced that preterm labor was the result of cervical dilation rather than the cause of it. In my experience, the McDonald procedure has worked well. Prolene no. 0 or 1 suture is used, and multiple small bites are taken. One or two circumferential sutures are placed and tied anteriorly.

While ruptured membranes are clear contraindication to a cerclage, a number of investigators have published descriptions of approaches to the dilated cervix with bulging, unruptured membranes. McDonald suggested using a moistened swab on a sponge forceps to reduce the bulging membranes.
Goodlin suggested transabdominal amniocentesis to reduce the tension in the amniotic cavity and allow retraction of “hourglassing” membranes. (see image below)
The author has used this approach on occasion, but it usually does not reduce the prolapsed portion of the membranes, and other techniques are needed.

Cervical cerclage.

Cervical cerclage.

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Olatunbosun and Dyck recommended the placement of patients in steep Trendelenburg position under general anesthesia and the use of 6 to 10 cervical stay sutures of no. 00 silk, then using traction on these sutures to cause the membranes to fall back into the uterine cavity before placing the cerclage.

Katz and Chez suggested that filling the bladder by instilling 400 to 500 cc of normal saline may lead to a retraction of the amniotic sac into the uterine cavity, thus facilitating cerclage placement.

I have used a foley catheter with a large balloon at the tip. With a full bladder, and the patient in steep Trendelenburg, the catheter is introduced in the cervix and the balloon gently inflated. The membrane usually retracts back inside the uterine cavity and the cerclage can be completed. The balloon is then deflated and the Foley is removed.

Charles and Edwards recommended the use of prophylactic antibiotics when emergency cerclage is performed.
They found a 2.6-fold increase in chorioamnionitis when cerclage was performed after, compared to before, 18 weeks’ gestation and a tripling in the likelihood of preterm PROM. The use of antibiotics should be individualized to specific cases. Please see the ACOG 2011 recommendations above. The use of tocolysis after an emergency cerclage also needs to be individualized.

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