Does ultrasound-guided intervention during repeat cesarean sections improve uterine scar architecture and reduce the number of scars? A prospective controlled clinical intervention trial

Abstract

Purpose To evaluate whether intraoperative ultrasound-guided detection and resection of the uterine scar during repeat/second cesarean can reduce the number of scars and improve uterine scar architecture. Materials and methods A prospective controlled clinical intervention trial was performed with the following groups: control group 1 (CS1-G): first cesarean; control group 2 (CS2-G): second cesarean utilizing the usual procedure and intervention group (Int-G): repeat/second cesarean with intervention. Transvaginal ultrasound scans were performed 6-9 months after each cesarean. Both primary (double scarring rate) and secondary outcomes [deficiency ratio=d/(b+d)] were analyzed. The deficiency ratio describes the thinning of the remaining myometrium (d=residual myometrial thickness) over the "apparent" defect (b=scar depth). Results In total, 124 of the 156 recruited women were examined, eight were excluded from analysis. The double scarring rate decreased from 42.9% (12/28) in CS2-G to 7.1% (2/28) in the Int-G [difference: 35.8%; 95% confidence interval (CI) (13.2, 54.5); P=0.002]. Two-way analysis of variance (ANOVA) revealed a significant difference between CS2-G and the Int-G in the deficiency ratio adjusted for elective/primary cesareans, with thicker remaining myometrium over the scar defect in the Int-G [difference: -0.24; 95% CI (-0.34, -0.15); P<0.001]. Conclusion Ultrasound-guided resection of the uterine scar area during repeat cesareans reduces the scarring rate and improves thickness of the remaining myometrium as detected by ultrasonography 6-9 months postoperatively.

Does the appearance of the cutaneous scar after cesarean section reflect the residual myometrial thickness?

“…The myometrial thinning at the scar was measured as a deficiency ratio and a ratio above 50% was considered to be severe. Our proposed RMT ratio has an inverse relationship to such a deficiency ratio and a higher RMT ratio reflects better healing [13]. Our data show both median and average RMT ratios of around 56% which contradicts the assumption that a deficiency above 50% is severe.…”

Anatomy of the sonographic post-cesarean uterus

“…The changes of the uterine anatomy caused by a CS can be responsible for complications in a subsequent pregnancy, and the ultrasound findings of these changes are believed to be helpful in assessing the probability of obstetrical complications [ 16 , 17 ]. Most studies were conducted before the methodology for measuring post-cesarean uterine niches was established and standardized by Jordans et al guidelines [ 9 ].…”

“…Seliger et al measured a deficiency ratio of the niche depth in relation to the combination of RMT and niche depth. Thinning at the scar location with a deficiency ratio greater than 50% was classified as severe deficiency [ 17 ]. Our results indicate that such a deficiency is not severe considering that it is very close to our median.…”

The B‐mode sonographic evaluation of the post‐caesarean uterine wall and its methodology: A study protocol

“…A ratio of more than 50% was classified as severe deficiency. 17 Previous work measured the CS scars longitudinally during the pregnancy and showed that the measurements are reproducible, but they utilized transvaginal ultrasound throughout second and third trimesters. 8 Transabdominal ultrasound is more practical in the later stages of pregnancy; thus it should be the preferred method for evaluating the lower uterine segment.…”

“…Other studies similarly utilized ratios for calculating the degree of thinning at the scar level. A ratio of more than 50% was classified as severe deficiency 17 …”