Study design
Prospective observational study. During the 2015–2020 period, all pregnant women between 15 and 24 weeks of gestation who presented with clinical cervical modification with or without membrane prolapse, or who were diagnosed with this condition after ultrasound diagnosis, were offered the option of undergoing emergency cerclage to prevent a preterm delivery.
Study population
Twenty-four pregnant women at 15 to 24 weeks gestation with cervical dilatation and bursa prolapse.
This procedure was offered only when one of the following clinical criterion was met: 1) cervical length <15 mm, measured with a 2.5–6.0 MHz transvaginal ultrasound probe (measurement had to be taken in the lithotomy position with the bladder completely empty, the shortest measurement was recorded) or 2) examination finding of a cervical dilatation between 1–4 cm, with visualization of the membranes at or exceeding the level of the external cervical os. Cerclage was not performed in the presence of fetal anomalies, bacterial vaginosis, uterine contractions, preterm premature rupture of membranes, active labor, and clinical symptoms or laboratory findings that suggest chorioamnionitis.
All patients underwent a 24-h observation period to rule out chorioamnionitis, bacterial vaginosis, and active labor before the surgery. In addition, vaginal ovules with clorhexidina were used 24 h before the operation.
Premature rupture of membranes (PROM) was determined using Actim® PROM (Medix Biochemica, Espoo, Finland) or by the direct identification of amniotic fluid thru the cervix and sonographic characteristics of oligohydramnios or anhydramnios. Chorioamnionitis was defined by fever >38ºC, significantly elevated maternal serum leukocyte count (>15000/mm3) (11), and the combination of positive amniotic Gram stain and glucose <5 mg/dl. Bacterial vaginosis was diagnosed by purulent vaginal discharge detected during the speculum examination on admission. Active labor was defined as the presence of regular uterine contractions, three or more in 10 minutes with cervical modifications.
Patients who underwent the procedure were informed that the surgeon may choose to make adaptations to the conventional cerclage techniques depending on the clinical conditions.
All patients provided the necessary consent to undergo cerclage and for participation in the study. This study was approved by the Ethical Committee of the Hospital Regional Universitario de Málaga.
Operative procedure
After making the diagnosis of cervical incompetence, our group decided to apply a modification to the cerclage technique consisting of:
- A first cerclage in a purse-string suture to ensure the reduction of the bag
- A subsequent occlusive cerclage to ensure good cervical competence
- To this technique a posterior cervical cleisis would be added depending on the cervical dilation and the degree of prolapse (TSEC)
The TSEC was reserved for those patients with dilation greater than 3 cm with a prolapsed bag, while the McDonald-type cerclage was performed in those patients with greater cervical length and less dilation, reserving double cerclage without cleisis for the remaining patients.
The technique for performing the TSEC was performed as follows:
- The cervix was exposed using Sim’s specula, after washing and asepsis of the vagina with chlorhexidine.
- The bag was reduced using a swab impregnated with sterile lubricant, until both cervical lips were exposed (normally the lower lip proves more difficult) and then pulled up using a Foester clamp.
- A Foley catheter was prepared and cut at the distal end, at the level of the upper edge of the inflated balloon. It was important not to leave any edges that could damage the amniotic sac.
- The Foley catheter was inserted and then filled depending on the degree of cervical dilation and the stage of the procedure. To do this, a third assistant helped to increase or reduce the drainage flow, depending on the stage of the procedure. This initially corrected the prolapse. It was then reduced in order to cross the cervical canal and later, once past the internal cervical os, the volume was increased again to fix the reduction of the bag and to facilitate safe cerclage (Fig. 1).
- The first cerclage was performed using Prolene 1. A purse-string suture was placed as cranially as possible and as close as possible to the level of the internal cervical os, with care taken not to damage the bladder. The suture was applied superficially, without going too deep into the cervical stroma, since the aim of this step is to keep the bag reduced once the Foley catheter had been removed, and to leave a segment of the cervix free on which to perform a second cerclage, so conglutination is completely guaranteed (Fig. 2).
- The tobacco pouch seam was then closed while the Foley catheter was simultaneously deflated and removed, ensuring that the cervix was completely closed.
- A second cerclage was performed with Mersilene tape, which was attached approximately 1 cm below the previous cerclage. The stitches in this suture were designed to conglutinate the cervix, including the anterior and posterior lips at both commissures (8 to 11 o’clock on the left edge and 4 to 1 o’clock on the right edge). The point applied on the lower edge extended from 7 to 5 o’clock, and it was positioned as cranially as possible. The knot was located at 12 o'clock (Fig. 3)
- The cervix was closed at the cervical os using Vycril 0. Two double stitches were applied in both commissures(Fig 4), plus a third in the central area (Fig. 5).
TSEC has a number of differences with respect to the techniques described so far.
- The aim of the first suture is to reduce the prolapse, isolate and protect the amniotic sac and provide the widest possible portion of cervix on which to apply the second cerclage, with the aim of containing the product of gestation and restoring the functionality and competence of the cervix. This is why this first step can be done with smaller sutures of 1 or 0 and with shorter needles. This facilitates access and execution of the suture as close as possible the internal cervical os, especially in situations where the cervix is very shortened and dilated. In addition, as its main objective is not to restore cervical functionality but to keep the pouch reduced, we can superficially affect the cervical tissue without going deep into it, which avoids possible accidental ruptures or lacerations of the pouch, as well as injuries to neighbouring organs (bladder, ureter or rectum). Unlike the Shirodkar technique, it is not necessary to detach or reject the bladder from the cervix, which makes it technically simpler and avoids possible complications associated with this approach.
- The second suture, as we have mentioned, has a functional objective of containment, but unlike what happens when performing the McDonald's technique, by having a completely free cervical stump, the application of the suture will be performed medially and covering the entire cervical diameter, thus joining both lips with what we understand we can give more strength to this suture, also requiring only three points as a triangle around the theoretical cervical canal.
- Finally, we finish the procedure by adding a cervical cleisis, which although as an isolated technique had already been applied, we believe that added to the previous steps, especially in patients with advanced dilatation and exposure of the amniotic sac, can offer additional protection against possible contamination or ascending infections, which are one of the main risks to be avoided in these patients.
Once the cerclage was performed, we evaluated its correct application using ultrasonographic visualization of the location of the suture, correct reduction of the pocket, and verification of a cervical length of >20 mm.
All patients were given ceftriazone intravenously in the operation room. Patients with bulging membranes at diagnosis, were given additional prophilactic erythromycine and ampiciline IV during the first 48 h after the procedure.
Prophylactic tocolysis was indicated with 50 mg transrectal indomethacin every 6 h during the first 48 h, keeping the patient on Trendelenburg for the first 24–48 h. The patients were discharged after 72 h. Prior to hospital discharge, an ultrasound reevaluation of the cervix was performed to confirm correct placement of the cerclage and the absence of cervical dilation or bag prolapse.
Cerclage removal was performed on an outpatient basis by sectioning the knots at week 37, if labor began, or when any circumstance that required termination of pregnancy occurred.
The main outcome measure was the mean latency until delivery from the placement of the different cerclages, as well as perinatal outcomes. The latency period was defined as the time elapsed from the application of cerclage to delivery. Other main outcomes included immediate maternal complications, including rupture of membranes, pregnancy loss, excessive blood loss during the procedure (more than 25 ml), or cervical injury.
Other evaluated outcomes were gestational age at delivery, time elapsed from the application of cerclage, birth weight, and neonatal outcomes.
Statistical Analyses
We performed an initial analysis of the frequency distribution of the independent variables. Subsequently, a bivariate analysis was performed to identify associations between variables. For bivariate analyses, we used the independent sample t-test to compare the mean values in two groups/categories of women when conditions of normality were present, and a Mann Whitney U test for the rest of cases. For comparisons between a greater number of groups, we used either a single-factor ANOVA or the non-parametric Kruskal–Wallis test according to the conditions of homoscedasticity that were evaluated using Levene's test. The chi-square test was used to compare qualitative variables. To analyze the relationship between quantitative variables, the Pearson´s correlation coefficient was used. The significance level was set at p < 0.05. We used logistic regression models to predict the results of the main dependent variable, latency to delivery. The models were constructed using the Intro procedure, including the sociodemographic and obstetric variables that were shown first to be significantly associated, using the typical stopping p-value thresholds for explanatory modeling.(17)