Hysteroscopic niche resection
Hysteroscopic niche resection was performed according to a standardized protocol under the general anesthesia in the Daycare Surgery department. A resectoscope (Ch. 26 model WA22061 with a 12° optic 22001A) equipped with a 3-mm-deep and 5-mm-wide loop (Olympus, Germany) was used. As distention medium we used 0.9% NaCl under 120 mmHg intrauterine pressure. Patients were in lithotomy position, after bimanual examination to determine the size and the position of the uterus, the cervix was disinfection and grasped with a tenaculum forceps. Dilatation of the cervix up to Hegar 9, aspiration of the endometrium for histological examination and hysteroscopic examination of the uterine cavity. Then the outflow tract was resected and the niche surface including all small vessels in the niche were coagulated (Figure S1). Patients were observed postoperatively for at least 3 hours.
Both procedures were performed by one trained doctor with extensive experience in performing the procedures.