Transabdominal Cerclage

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To follow along, we suggest reading SMFM Consult Series #65: Transabdominal Cerclage 

  • What is the background to cerclages? 

    • Preterm birth is still the leading cause of neonatal morbidity and mortality 

    • Cervical insufficiency (inability of cervix to retain a pregnancy, characterized by painless cervical dilation usually in middle of second trimester) is an important cause of preterm birth 

    • Diagnosis of cervical insufficiency: 

      • History of one or more second-trimester losses after painless cervical dilation in absence of labor or abruption 

    • Cervical cerclages are indicated for those with cervical insufficiency – most are done transvaginally 

      • McDonald or Shirodkar method 

      • Other indications = history of PTB <34 weeks, cervical length <25 mm before 24 weeks 

      • Advanced cervical dilation before 24 weeks 

    • Transabdominal cerclage (TAC) are also an option - first described by Benson and Durfee in 1965 

      • Advantages: can be placed higher, in the cervicoisthmic junction, so may provide greater structural support  

        • Avoids presence of foreign body in vagina, so may decrease risk of PPROM or IAI 

      • Disadvantages: more morbid and more complicated surgery because need abdominal access and dissection, necessitates cesarean delivery 

  • So when is a TAC indicated? 

    • TACs are usually not offered as first line treatment for cervical insufficiency 

      • Due to increased morbidity of placement and need for CS 

      • Exception is for those where transvaginal cerclage would be very difficult to place 

        • Ie. Those with history of multiple LEEPs or trachelectomy 

    • More often, TAC is used for patients with unsuccessful transvaginal cerclage 

      • Previous unsuccessful TV cerclage = spontaneous delivery before 28 weeks of gestation 

      • TAC reduced risk of recurrent preterm birth compared with repeat transvaginal cerclage in patient with a previous delivery <33-34 weeks gestation 

    • Multicentre Abdominal vs. Vaginal Randomized Intervention of Cerclage (MAVRIC) study 

      • Randomized controlled trial 

      • Compared use of a TAC, high vaginal cerclage, and low vaginal cerclage among patients with previous miscarriage or preterm birth between 14-28 weeks of gestation with transvaginal cerclage in situ in previous pregnancy 

        • TACs were performed as an open procedure either before pregnancy or up to 14 weeks 

        • Vaginal cerclages done between 10-16 weeks gestation 

      • Findings: preterm birth rates <32 weeks were significantly lower with TAC compared with both low vaginal cerclage (8% vs. 33%%, RR 0.23, 95% CI 0.07-0.76), and high vaginal cerclage (8% vs. 38%, RR 0.2, 95% CI 0.06-0.64) 

      • NNT to prevent 1 preterm birth when TAC was compared with low vaginal cerclage was 3.9, and compared with high vaginal cerclage was 3.2 

  • How is a TAC placed?

    • We won’t go into full detail, since that’s a little beyond the scope of a podcast! 

    • Open technique 

      • Typically done via spinal or regional anesthesia 

      • Pfannenstiel incision 

      • Uterus is exteriorized and surgeon identifies and palpates the uterine vessels bilaterally 

      • Uterine vessels are retracted laterally → create an avascular space between the uterus and the vessels in the broad ligament at the level of the internal os of the cervix 

      • Non-absorbable thick braided 5mm suture (ie. Mersilene tape) guided through space with right-angle clamp 

      • Suture is tied anteriorly or posteriorly and left in place 

    • Minimally invasive technique 

      • Many different techniques have been described, using both traditional laparoscopy and robotic surgery

      • Most will use 3-port laparoscopic approach, some with fourth suprapubic assistant port 

      • Some will use a uterine manipulator (usually done prior to pregnancy) 

      • Can dissect the uterovesical and paravesical spaces and make a window in the broad ligament through which the suture is placed 

      • Suture used can be same nonabsorbable thick braided 5-mm suture (Mersilene tape), and some places have described using mono-filament, non-braided polypropylene suture 

      • Suture is tied anteriorly or posterior and left in-situ 

  • Is laparoscopic or open better? 

    • Studies show that laparoscopic TACs are associated with less risk of blood loss and shorter hospital stays 

    • However, laparoscopic procedures take longer 

    • Other studies show no difference in blood loss, operative time, or hospital stay between the two 

    • Overall, similar rates of pregnancy and miscarriage rates after laparoscopic and open TAC placement 

    • Many studies have also shown similar preterm birth rates <34 weeks with both approaches, but overall, no RCTs as of yet 

    • Therefore, both laparoscopic and open TAC are acceptable 

  • Should I tocolyze? 

    • No evidence to suggest that tocolysis is helpful 

  • Ideal time for placement 

    • Can be placed before pregnancy or in the first trimester 

    • However, if there is an indication for TAC after first trimester, placement up to 22 weeks can be considered 

  • Management of a pregnancy after TAC? 

  • Management antepartum 

    • MFM consultation should be obtained before TAC placement is done 

    • Can continue with MFM consultation if questions arise 

    • Should we continue to measure transvaginal cervical lengths? 

      • Several studies show that although cervical shortening after cerclage may increase the risk of preterm birth, cervical length does not directly correlate with outcomes 

      • Rescue cerclage does not improve outcomes in the setting of a short cervix after cerclage 

      • Therefore, SMFM does NOT recommend routine transvaginal cervical length screening for patients with TACs 

    • Should we use progesterone? 

      • In the MAVRIC trial, 27% of patients used progesterone (17% in TAC, 28% in high vaginal cerclage and 48% in low vaginal cerclage) 

      • However, since this trial, the FDA has withdrawn approval of IM progesterone 

      • Benefit of adding vaginal progesterone to treatment regimen of patients with cerclage is unknown

      • SMFM recommend having a risk-benefit discussion of supplemental vaginal progesterone be undertaken and shared decision making take place

        • What we did at Penn: If they were already on progesterone, we didn’t take it away. If they weren’t on progesterone already, we don’t recommend 

        • What did they do in UW? - same

  • What to do in setting of pregnancy loss 

    • If needed, D&E can be done with a TAC in situ 

    • Large retrospective study of 142 patients with TAC found that 14 patients underwent 19 D&E procedures, with 15 of those occurring at <12 weeks 

    • Osmotic dilators and standard surgical techniques were used 

    • No major complications noted 

    • SMFM recommends that pregnancy loss be managed with D&C or D&E with TAC in situ or with obstetrical management after laparoscopic removal of TAC depending on gestational age 

  • Timing of delivery 

    • Cesarean delivery is recommended, as TACs are not removed 

    • There have been case reports of uterine dehiscence or uterine rupture when patients with TAC labor 

    • Therefore, recommendation is delivery timing similar to previous myomectomy (37w0d-39w0d) 

    • Leave TAC in situ for future pregnancies