Cervical Cerclage in Obstetrics: Indications, Contraindications, and Complications

Introduction to Cervical Cerclage

Cervical cerclage is a surgical procedure used to prevent preterm birth or second-trimester pregnancy loss in women with cervical insufficiency or other related conditions. This procedure involves placing a stitch around the cervix to keep it closed during pregnancy, reducing the risk of premature dilation and subsequent pregnancy loss.

Indications for Cervical Cerclage

The decision to perform cervical cerclage is based on several indications, primarily related to the risk of preterm birth due to cervical incompetence. These indications include:

1. History-Indicated Cerclage: This is recommended for women with a history of one or more second-trimester pregnancy losses due to painless cervical dilation in the absence of labor or abruption.
2. Ultrasound-Indicated Cerclage: For women with a history of preterm birth and a short cervix (less than 25 mm) detected by transvaginal ultrasound between 16 and 24 weeks of gestation.
3. Physical Exam-Indicated Cerclage: This is considered when cervical dilation is discovered during the second trimester in the absence of contractions.

Preoperative Evaluation

Before performing cervical cerclage, a thorough preoperative evaluation is essential to ensure the patient is an appropriate candidate for the procedure. The evaluation includes:

1. Detailed Obstetric History: A comprehensive history of previous pregnancies, including any previous preterm births, miscarriages, or cervical surgeries, should be taken.
2. Ultrasound Assessment: Transvaginal ultrasound is used to measure cervical length and assess the presence of funneling or cervical dilation.
3. Infection Screening: Testing for infections such as bacterial vaginosis, chlamydia, and gonorrhea is important as infections can increase the risk of complications.
4. Pelvic Examination: A physical examination to check for cervical dilation, effacement, and other abnormalities is necessary.
5. Counseling: Patients should be counseled about the risks, benefits, and alternatives to cervical cerclage. This includes discussing the potential for complications and the need for follow-up care.

Contraindications

Cervical cerclage is not suitable for all patients. Contraindications include:

1. Active Preterm Labor: If the patient is already in active labor, cervical cerclage is not recommended.
2. Intrauterine Infection: The presence of chorioamnionitis or any other intrauterine infection is a contraindication.
3. Fetal Anomalies: If the fetus has been diagnosed with a lethal anomaly or there is evidence of intrauterine fetal demise, cerclage is not indicated.
4. Vaginal Bleeding: Significant vaginal bleeding, particularly if it suggests placental abruption, contraindicates the procedure.
5. Ruptured Membranes: If the membranes have ruptured, cervical cerclage is contraindicated due to the high risk of infection and complications.

Surgical Techniques and Steps

There are several techniques for performing cervical cerclage, with the choice of method depending on the clinical scenario and surgeon preference. The three most common techniques are:

1. McDonald Cerclage

• Procedure: The McDonald technique is the most commonly used method. It involves placing a purse-string suture around the cervix at the level of the internal os. The suture is tightened to approximate the cervical tissues, effectively reinforcing the cervix.
• Steps:
  1. The patient is placed in a lithotomy position.
  2. A speculum is inserted to visualize the cervix.
  3. A Mersilene tape or a similar non-absorbable suture is threaded through a needle.
  4. The suture is passed around the cervix in a purse-string fashion.
  5. The suture is tied anteriorly, and the ends are left long to facilitate removal.

2. Shirodkar Cerclage

• Procedure: The Shirodkar method involves placing the suture higher up in the cervix, closer to the internal os, and may require dissection of the bladder anteriorly.
• Steps:
  1. The patient is positioned similarly to the McDonald procedure.
  2. The anterior vaginal wall is retracted, and the bladder is dissected away from the cervix.
  3. The suture is placed high on the cervix, typically through the cervicovaginal junction.
  4. The suture is tied posteriorly, and the bladder is repositioned.

3. Transabdominal Cerclage

• Procedure: This technique is reserved for women with a history of failed transvaginal cerclage or with a severely shortened or absent cervix. It involves placing the cerclage via an abdominal incision, often during a laparotomy or laparoscopic procedure.
• Steps:
  1. The patient is placed under general anesthesia.
  2. A low transverse abdominal incision is made, and the uterus is exposed.
  3. A suture is placed at the level of the internal os, either around the entire cervix or through the uterine isthmus.
  4. The suture is tied anteriorly or posteriorly, depending on the surgeon's preference.

Postoperative Care

Postoperative care is crucial to monitor for complications and ensure the success of the cerclage. Key aspects include:

1. Monitoring: Patients should be observed for signs of labor, rupture of membranes, or infection. Vital signs and uterine activity should be closely monitored.
2. Antibiotic Prophylaxis: Some practitioners recommend a short course of antibiotics postoperatively to reduce the risk of infection, though this practice is not universally accepted.
3. Activity Modification: Patients are often advised to avoid heavy lifting, sexual intercourse, and prolonged standing. Bed rest may be recommended in some cases, though evidence supporting strict bed rest is limited.
4. Follow-Up: Regular follow-up visits are essential to monitor cervical length, fetal growth, and the overall health of the pregnancy. Ultrasound may be used periodically to assess the status of the cerclage.
5. Removal of Cerclage: In most cases, the cerclage is removed at 36-37 weeks of gestation, or earlier if the patient goes into labor or if the membranes rupture. Removal is usually done in an outpatient setting without anesthesia.

Possible Complications

While cervical cerclage is generally safe, it is associated with several potential complications:

1. Infection: Chorioamnionitis or other infections can occur, particularly if the procedure is performed in the presence of an undiagnosed infection.
2. Preterm Labor: In some cases, the placement of the cerclage may induce preterm labor.
3. Rupture of Membranes: The procedure can lead to premature rupture of membranes, increasing the risk of preterm birth.
4. Cervical Laceration: During placement or removal of the cerclage, the cervix may be inadvertently lacerated.
5. Cervical Dystocia: In rare cases, the cervix may fail to dilate during labor after cerclage removal, requiring cesarean delivery.
6. Hemorrhage: Bleeding may occur during the procedure, particularly with the Shirodkar method.

Different Techniques and Approaches

The choice of technique for cervical cerclage is influenced by patient history, anatomical considerations, and surgeon experience. Below are comparisons and considerations for the different approaches:

• McDonald vs. Shirodkar: The McDonald technique is simpler and less invasive, making it the most commonly used method. The Shirodkar technique, while more complex, may offer additional support in cases of more severe cervical insufficiency.
• Transabdominal Cerclage: This method is reserved for cases where transvaginal cerclage has failed or is anatomically unfeasible. It requires a more invasive approach but offers a higher success rate in certain high-risk populations.

Prognosis and Outcome

The prognosis following cervical cerclage largely depends on the underlying condition, timing of the procedure, and the presence of any complications. Successful cerclage can significantly reduce the risk of preterm birth in women with cervical insufficiency, with live birth rates reported as high as 85-90% in properly selected cases.

• Success Rates: Women with history-indicated or ultrasound-indicated cerclage typically have good outcomes, particularly when the procedure is performed before significant cervical changes occur.
• Impact on Future Pregnancies: Women who undergo cervical cerclage may require the procedure in future pregnancies, depending on the recurrence of cervical insufficiency.
• Long-Term Outcomes: The long-term outcomes for the fetus are generally favorable if the pregnancy reaches term. However, preterm birth remains a risk, particularly in cases complicated by infection or rupture of membranes.

Alternative Options

For patients who are not candidates for cervical cerclage or who prefer to avoid surgery, alternative options include:

• Progesterone Therapy: Vaginal or intramuscular progesterone has been shown to reduce the risk of preterm birth in women with a history of preterm labor or a short cervix.
• Pessary: Cervical pessary placement is a non-surgical option that involves placing a silicone device around the cervix to provide support. The effectiveness of pessary use is still under investigation, and it is not widely adopted in all practice settings.
• Close Monitoring: Some women may be managed with close surveillance, including frequent cervical length measurements and early intervention if significant changes are observed.

Average Cost

The cost of cervical cerclage varies depending on the method used and the healthcare setting. In the United States, the procedure can range from $1,500 to $4,000, not including additional costs for preoperative evaluation, anesthesia, and postoperative care. Insurance coverage varies, and patients should be advised to check with their providers regarding out-of-pocket expenses.

Recent Advances

Recent research and technological advances have improved the understanding and management of cervical insufficiency. Key developments include:

• Biomarkers: The identification of biomarkers associated with cervical insufficiency and preterm birth may allow for earlier and more accurate identification of at-risk women.
• Enhanced Imaging Techniques: Advances in ultrasound and MRI technology have improved the ability to assess cervical length and integrity, aiding in the decision-making process for cerclage placement.
• Minimally Invasive Techniques: The development of laparoscopic and robotic-assisted techniques for transabdominal cerclage offers a less invasive option with potentially faster recovery times.
• Personalized Medicine: Ongoing research into the genetic and molecular basis of cervical insufficiency may lead to more personalized approaches to treatment, including targeted therapies.