Surgery: The McDonald Cerclage
/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!
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.