Cervical Incompetence and Cerclage - 7 - All Cerclages are Not Created Equally
In February of 2006, Dr. Zarko Alfirevic published an editorial entitled: "Cerclage: We All Know How to Do It but Can’t Agree When to Do It.” (Obstet Gynecol 2006;107:219-20). The editorial was written as a commentary to an article in the same issue by Daskalakis and colleagues (Obstet Gynecol 2006;107:221-26) in which the authors described their success with rescue cerclage placed in women between 18 and 26 weeks in whom significant cervical changes (dilation and bulging of membranes) were detected by transvaginal ultrasound screening. The study was not randomized, comprised a total of 46 women, and simply compared outcomes between the 29 who elected to proceed with cerclage and the 17 who chose simply to be treated with bedrest, tocolysis, and antibiotics (also prescribed to the ‘cerclage group’).
The results of the study were quite impressive. In the cerclage group, the mean prolongation of pregnancy was almost 9 weeks and the mean birth weight was 2101 g. These results contrasted dramatically with the ‘control’ group, mean prolongation of 3 weeks and birth weight of 739 g. Twenty-five of the cerclage pregnancies resulted in live births compared with 7 of 17 in the bedrest group. Other outcomes in cerclage vs controls included: neonatal survival 96% vs 57%; delivery at less than 32 weeks 31% vs 94%; and, adnissions to the neonatal intensive care unit 28% vs 86%. The reduction in overall perinatal mortality from the bedrest group of 76% to the cerclage group of 17% is certainly hard to ignore (and even harder to explain to a patient in the same situation in an objective manner). Furthermore, no significant surgical complications were noted in the group that received a cerclage.
Although the potential flaws of a nonrandomized study with a small cohort of women are correctly pointed out by Dr. Alfirevic in his editorial review, and his compliment regarding the success and low maternal morbidity as “testament to the surgical skills of the team” was warranted, I sense a degree of skepticism throughout his comments. And, while it is true that the published literature does not necessarily support the results, personally, I believe them because of the similar (if not even better) success rates we have experienced throughout the years. Indeed, I now fully believe that the premise of the editorial’s title regarding “Cerclage: We All Know How to Do It…” is what is fundamentally flawed and that is perhaps the major reason such disparate results regarding cerclage pervade the literature.
Although cervical cerclage often can be a relatively simple procedure, to say all cerclages are placed equally well is like saying all physicians have comparable skills because they all happened to finish residencies. The bottom line is it just ain’t so! Like any other surgical procedure, the results depend on the skills and experiences of the surgeon. So, with that as background, in our next post, I really will discuss the technique and rationale for the same we regularly use for cerclage…