Investigation of changes in endometrial microbiota in isthmoseli cases

INTRODUCTION AND AIM: Isthmocele, also known as cesarean scar defect (CSD), is the disruption of the integrity of the myometrium in the cesarean section incision and the indentation of the opening in the myometrium towards the visceral peritoneum. Residual menstrual blood accumulating in the isthmocele sac can cause chronic endometritis. In the study, the clinical success of the hysteroscopic surgical approach (isthmoplasty) applied to the patients with isthmocele was investigated. In addition, the effect of isthmoplasty on the endometrial cavity microbiome was investigated. MATERIALS AND METHODS: Forty women who presented with symptoms of isthmocele who were found to have isthmocele in their transvaginal ultrasonographies (TVUSG) were included in the study. Microbiological culture and microbiome analyzes by nucleic acid isolation, 16S rRNA PCR, next generation sequencing, bioinformatics and statistical analysis were applied to lavage samples taken from the uterine cavity before and 3 months after surgery. Isthmocele diameter measurements and symptom inquiries were made before and during postoperative controls. RESULTS: The study was completed with 22 women. The dimensions of the isthmocele decreased after surgery (p<0.001). Isthmocele symptoms such as abnormal uterine bleeding, chronic pelvic pain, secondary infertility improved (p<0.001). Twelve (%66.) of 18 patients who applied for secondary infertility became pregnant spontaneously within the postoperative follow-up period (mean 8.9 months). Endometrial microbiome consisting predominantly of anaerobic bacteria in the endometrial lavage fluids taken before the surgical treatment, transformed into lactobacilli. CONCLUSION: CSD can be effectively treated with hysteroscopic isthmoplasty in selected cases. The return of the endometrial microbial flora to its normal physiological structure after closure of the CSD is the main reason for the improvement of the symptoms developing secondary to isthmocele, especially secondary infertility. Keywords: Endometrial microbiome, hysteroscopic, infertility, isthmocele, isthmoplasty.