Comparison of the effectiveness of ultrasound diagnosis in assessment of uterine scar defets after cesarean section

Aim: To improve the effectiveness of uterine scar assessment after cesarean section (CS) using ultrasound techniques. Materials and methods: A comparative study included 65 patients with thinned uterine scar after CS, who were planning repeated pregnancy. The first stage of research was a routine pelvic ultrasound examination on the outpatient basis, which was performed outside the Research Center for Obstetrics, Gynecology and Perinatology. The second stage was expert pelvic ultrasound examination and scar measurements using a modified Delphi procedure that was performed in the National Medical Research Center for Obstetrics, Gynecology and Perinatology. At the third stage, two specialists of the Center independently performed complex ultrasound, which included expert pelvic ultrasound examination and hysterosalpingography (HSG). The results of measurements of cesarean section scars obtained at the 1st and 2nd stages of research and during expert pelvic ultrasound examination and HSG, as well as the consistency of measurement results obtained by 2 sonographers at the third stage were evaluated. Results: The comparative analysis of routine and expert pelvic ultrasound showed that statistically significant differences were found in measurement of residual myometrial thickness (RMT) (3.21 (1.2) mm and 2.76 (1.0) mm, respectively, р<0.05), width and depth of SC scar. The comparative analysis of expert US and HSG showed that statistically significant differences were found in measurements of RMT (2.83 (1.1) mm and 2.4 (0.95) mm, respectively, р<0,05, width, length and depth of niche. The comparative analysis of the results independently obtained by 2 sonographers during performance of expert ultrasound and HSG did not show statistically significant differences. However, according to the Bland-Altman analysis, the scatter plot of the obtained values was less in HSG than in expert US. This indicates a greater reproducibility of the research method. Conclusion: When uterine scar defect after cesarean section is found during ultrasound at the stage of outpatient examination, it is appropriate to refer the patient to a specialized medical institution to undergo examination there and to define management strategy. Expert pelvic US using Delphi criteria helps to determine how accurately cesarean section scars can be detected. In doubtful cases, as well as when it is required to take a decision on necessity and the volume of surgery, it is preferable to perform HSG that ensures high reproducibility and provides additional "navigation" information for the surgeon.

uterine scar defect after cesarean section (CS scar defect), niche, cesarean section, ultrasound examination, hysterosalpingography