Surgery: The McDonald Cerclage

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What is a McDonald cerclage? 

  • Definition: a suture placed around the cervix in a purse-string fashion and tied anteriorly 

  • Purpose: to decrease the risk of preterm birth in patients with

    • History of preterm birth and short cervix 

    • Second trimester with open cervix <24 weeks 

  • For more indications, please see our prevention of preterm birth episode! 

UPTODATE

Today we will focus on the surgical steps:

  • For pictures, we still like Atlas of Pelvic Surgery: 

    Pre-operative 

    • Surgical consent 

      • Review the way the procedure is done 

      • Discuss risks, benefits, and alternatives

        • Risks: injury to organs around the cervix (ie. bowel, bladder, vagina), small risk of breaking the bag of water and losing the pregnancy, infection, bleeding, etc.  

        • Benefits: could decrease preterm birth before 37 and 34 weeks compared to women who did not get cerclage (RR 0.77, 95% CI 0.66 to 0.89 based on a Cochrane review) 

        • Alternatives: doing nothing, using vaginal progesterone, etc. 

    • Preoperative work up 

      • Most providers will not need a CBC or other additional work up in young, healthy patients 

      • Some hospitals may require a type and screen for all patients going to the operating room, and most hospitals nowadays may also require a COVID swab 

        • Patients who are Rh negative: typically do NOT give Rhogam just for cerclage, given that any bleeding caused is presumably only cervical bleeding and we are not traumatizing the pregnancy.

      • Ultrasound, genetic screening 

        • General practice is to perform genetic screening if a patient desires it (ie. we don’t want to put a cerclage into a pregnancy that is affected by aneuploidy in a patient who may desire termination) 

        • Ultrasound - make sure there are not obvious fetal malformations early on (ie. anencephaly), make sure there is a fetal heartbeat before the procedure.

    • Anesthesia 

      • Most procedures are done with neuraxial anesthesia (ie. Spinal) 

    • Expectations 

      • Patients will go home same day 

      • Some can have some cramping and spotting, but if more than cramping, should come in for evaluation 

  • During the surgery 

    • Patient should have adequate anesthesia in the operating room and be prepped and draped 

    • Positioning: 

      • Dorsal lithotomy - yellowfins vs candy canes 

      • Tip: make sure patient’s bottom is slightly hanging off of the bed; put patients in slight Trendelenburg for visualization  

      • Empty bladder - usually helpful to be able to visualize cervix 

    • Surgical steps

      • Evaluate the cervix after adequate anesthesia has been achieved even if you examined them before anesthesia

        • After anesthesia and relaxation, the cervix can appear different or even more open! 

        • Evaluation should be done visually first in case there are exposed membranes 

      • Achieve visualization 

        • Can place a weighted speculum into the posterior vagina, or can also place 3 Bryskie retractors to visualize the cervix 

        • Place two ringed forceps onto the anterior and posterior lip of the cervix - this allows for maneuverability of the cervix 

        • Visualize the reflection of the bladder on the anterior cervix 

      • Place the suture

        • Permanent suture is used 

          • Types: Mersilene tape or a 0- or 1- Ti-Cron (coated braided polyester suture) - usually will use a large caliber suture

          • If using Ti-Cron, will usually use a mayo needle given large size of the needle that comes with the Ti-Cron 

        •  Usually the suture is placed with 4 or 5 bites 

          • Start at 12 or 1 o’clock on the cervix, as far back as possible without getting into the bladder 

          • The next bites should avoid 3 and 9 o’clock where the vessels are 

          • Assistants should use Bryskie retractors to hold back the vaginal walls, and the surgeon should use the two ringed forceps to maneuver the cervix 

        • Tying the suture 

          • Tighten the suture on both sides and recheck the cervix to make sure the suture is tight and the cervix is closed 

          • Tying: Fei ties 6 knots for Ti-Cron, and 4 for Mersilene tape. Then, for ease of removal later, I will tie an airknot and then tie down four more knots. You can also tag Mersilene tape with another soft non-absorbable suture (i.e., silk).

  • Post-operative 

    • In the hospital, the patient needs to have their spinal/epidural anesthesia wear off before they can go home 

      • Should be able to walk 

      • Should be able to urinate 

      • Check fetal heart tones 

    • Indocin and antibiotics or no? 

      • Er… it depends and there is a lot of conflicting data 

      • There is a randomized controlled trial of only 53 patients in 2014 looking at antibiotics and indocin for exam-indicated cerclages 

        • This showed that there was increased time to delivery for those that received Indomethacin and antibiotics, but gestational age at delivery and neonatal outcomes were the same in both groups 

        • Then a repeat study was done in 2020 that showed similar results (increase in latency):

        • So… I think many people would do Indocin and antibiotics for exam-indicated cerclages 

      • A retrospective study for all cerclages showed that there was no increase in gestational age or neonatal outcomes 

        • So, maybe not use indocin in history-indicated cerclages.

    • Follow-up 

      • Usually 1-2 week follow up for cerclage check in office.