Optimisation of the McDonald cerclage: Despite the well-known McDonald cerclage method, we felt it was useful to mention the optimising measures that have been developed over decades of use.
for more pictures see https://spaetling.net/optimierung-der-…ge-nach-mcdonald/
Pre-treatment: A disinfecting vaginal suppository is inserted the day before. For prolapse and partial prolapse, we consider perioperative antibiotics to be useful. The operation is performed under spinal anaesthesia. We use octenidine for vaginal disinfection.
Procedure
Placement of the cerclage tape
The operation should be performed by three people if possible. Insertion of an Hänge- and Breisky speculum to unfold the vagina, grasping the anterior and posterior labia majora with light caudal traction using tissue forceps. If the amniotic sac has prolapsed, it can be pushed up with a small swab. We always use an Mersilene tape with needles at the ends (Ethicon BT3-5 mm 40 cm). The larger needles that are also available are almost always a hindrance. Half of the tape is marked with a Pean clamp. Tape ends of equal length make knotting easier, especially with the tape in the desired high position. To place the tape as high as possible, we place the blunt needle on the vaginal skin at the fold and slide it cranially, applying light pressure without piercing the skin.
Once we have reached the desired height, we increase the pressure until the needle penetrates the skin with a slight noise and sudden release of the counter-pressure, with the needle tip in front of the cervical stroma. We try to avoid penetration of the stroma, as this is often very soft, and we want to avoid injury to the amniotic sac, especially in the case of prolapsed amniotic sac or funnel-shaped internal os. We puncture at 6 o’clock, at 3 o’clock we withdraw and puncture again, using less than the described 10 mm between puncture and withdrawal. The needle is removed at 12 o’clock. The index finger of the free hand can make it easier to find the needle tip. The band is then pulled through to exactly half. The Pean clamp is then at 6 o’clock and can be removed. Unlike Shirodkar’s cerclage, the convexity of the needle always points to the centre of the cervix.
Now we proceed in the same way from 6 o’clock to 9 o’clock to 12 o’clock. It can be helpful to use a second needle holder to hold the needle. After cutting the needles, tie a knot. It is best to tie the knot by choosing a simple knot and pulling the band laterally with both index fingers directly at the knot. Meanwhile, the assistant carefully removes the swab holding the amniotic sac.
We do not tie the knot with maximum force, but we want to feel the internal os about 5 mm (fingertip) wide. We then tie three knots in alternating directions and tie a small loop about 2 cm long, which makes it easier to find and remove later.
If the bladder ruptures during the cerclage, a TMV should be connected.
TIP
For later removal at about 36 weeks of gestation, we take a long dissecting scissors without further preparation after a gynaecological examination, grasp the bridge with a long straight clamp, pull it to the right until the band distal to the knot becomes visible, slide the closed scissors under the band, tilt and open them a little so that the band slides between the branches. Then we cut and remove the ligament.
We insert an indwelling bladder catheter until the patient is able to stand up independently again. A tamponade, the tip of which we moisten with povidone, is rarely necessary. Because of the possibility of triggering contractions, we prescribe bolus oxytocin with fenoterol (4 µg/12 min) for at least 24 hours.
Ludwig Spätling, Gynaecological Clinic, Fulda Clinic,
Abstract from Gynäkol. prax. 39:437-449 (2015)