Assessing lateral uterine wall defects and residual myometrial thickness after cesarean section

The association between gynecological complaints and the uterine sonographic features in women with a history of cesarean section

PURPOSE

The aim of this study is to investigate the association between post-cesarean sonographic uterine measures, dysmenorrhea, and bleeding disorders.

METHODS

This is a cross-sectional study where 500 women with a history of only one cesarean section (CS) were recruited. A transvaginal transducer, GE RIC6-12-D was used for the acquisition of volumetric datasets 18 ± 7 months postpartum. Uterine length (UL), cervical length (CL), niche length (L), niche depth (D), niche width (W), fibrosis length (FL), fibrosis depth (FD), residual myometrial thickness (RMT), endometrial thickness (EM), scar to internal os distance (SO), anterior myometrial thickness superior (sAMT) and inferior (iAMT) to the scar, and the posterior myometrial thickness opposite the scar (PMT), superior (sPMT), and inferior to it (iPMT) were measured. Logistic regression with odds ratios (OR), 95% confidence intervals (CI) and ROC curves were utilized.

RESULTS

The proportion of patients with incident post-cesarean bleeding disorders and dysmenorrhoea was 36% (CI 32%, 40%) and 17% (CI 14%, 21%) respectively. Univariate logistic regression showed that only UL was associated with bleeding disorders [OR 1.04 (CI 1.01,10.7) p value 0.005], whereas dysmenorrhea was associated with RMT [OR 0.82 (CI 0.71,0.95) p value 0.008], SO [OR 0.91 (CI 0.86,0.98) p value 0.01], and RMT ratio [OR 0.98 (CI 0.97,0.99) p value 0.03]. Multivariate logistic regression for dysmenorrhoea including SO and RMT remains statistically significant with p values <0.05 and area under the curve of 0.66.

CONCLUSION

There is an association between sonographic appearance of CS scars and dysmenorrhoea. Nevertheless, the association is weak and other biological post-cesarean characteristics should be explored as potential causes.

The Novel Parallel Closure Technique Compared to Single-Layer Closure of the Uterus After Primary Cesarean Section Decreases the Incidence of Isthmocele Formation and Increases Residual Myometrial Thickness

Background Isthmocele or a scar defect is a relatively common consequence of cesarean section resulting in menstrual disturbances and infertility and may compromise the myometrial integrity of the uterus in women contemplating subsequent vaginal birth. Several preventive measures have been suggested, including the modification of surgical techniques used for the closure of the uterine incision. The current study aimed to compare the incidence of isthmocele and assess residual myometrial thickness in women who underwent single versus parallel layered closure to approximate the endo-myometrial layer during cesarean section. Methodology This retrospective study evaluated data of women undergoing their first cesarean section under elective conditions (n = 497) where the uterine incision was closed using a single (n = 295) or a parallel layer (n = 202) technique. Patients were evaluated twice, at 3-6 months and 18 months postpartum, with a transvaginal ultrasound noting the presence or absence of an isthmocele and measurement of the residual myometrial thickness. Results Regardless of the closure technique, 64 (12.9%) women had an ultrasound-diagnosed isthmocele. Significantly fewer patients in the parallel-layer closure group presented with an isthmocele both at 3-6 (13.6 vs. 6.9%; p = 0.019) and 18 months (16.3 vs. 7.8%; p = 0.009) postpartum. Residual myometrium was significantly thicker in the parallel-layer closure group (8.0 vs. 13.2 mm at 3-6 months postpartum; p = 0.000 and 7.2 vs. 12.3 mm at 18 months postpartum; p = 0.004). For all patients, a retroverted position of the uterus at 3-6 months follow-up examination significantly increased the frequency of isthmocele (36/395 (9.1%) with an anteverted uterus and 18/102 (17.6%) with a retroverted uterus; p = 0.002). In patients with a single-layer closure, a retroverted uterus at the 3-6-month follow-up was associated with an isthmocele in 29.5% (18/61) of patients, while no isthmocele was recorded when the uterus was retroverted in the parallel-layer closure group (0/41) (p = 0.001). At 18 months postpartum, of the 64 patients with an isthmocele, 26 (40.6%) presented with abnormal uterine bleeding mainly in the form of postmenstrual spotting. Of the 26 patients with abnormal bleeding, 23 were in the single-layer and three were in the parallel-layer closure group. Conclusions The parallel-layer closure when compared to a single-layer closure of the uterine incision in patients undergoing primary cesarean section decreased the incidence of isthmocele formation and increased residual myometrial thickness. More patients in the single-layer closure group had menstrual cycle disturbances at 18 months postpartum.

The effect of the onset of labor on the characteristics of the cesarean scar

OBJECTIVE

To assess the effect of cesarean section (CS) timing, elective versus unplanned, on the residual myometrial thickness (RMT) and CS scars.

METHODS

This is a prospective single-blinded observational cohort study with 186 observations. Patients indicated to undergo first singleton CS were preoperatively recruited. Exclusion criteria were history of repeated CS, vertical hysterotomy, diabetes, and additional uterine surgeries. Sonographic examination was performed for assessing the RMT ratio, the presence of a niche, fibrosis, and the distance from the scar to the internal os (SO) 1 year after CS. Power analysis was performed with 0.05 α, 0.1 β, and all statistical analyses were conducted with Stata^® .

RESULTS

Wilcoxon rank-sum test for the association between CS timing, RMT ratio and SO showed Z values of -0.59 and -4.94 (P = 0.553 and P < 0.001), respectively. There was no association between CS timing and niches and fibrosis (P > 0.99 and P = 0.268, respectively). Linear regression between SO and the extent of cervical dilatation showed a -0.45 β (95% confidence interval -0.68 to -0.21) and a 10.22-mm intercept (P < 0.001).

CONCLUSION

RMT is independent of the timing of CS, but the SO distance shows a negative linear relationship with the cervical dilatation.