Hysteroscopic "360°" Surgery for Improvement of Symptoms in Cesarean Scar Defects

Inclusion Criteria: * Patients with surgical adaptation: changes in menstruation after cesarean section (prolonged menstrual period) * No surgical contraindications; * Age 18-45 years old; * The thickness of residual muscle layer measured by ultrasound is greater than or equal to 2.5mm; * Patients with symptoms that have not improved significantly for more than 1 month after oral short-acting contraceptive cycle treatment or who strongly require surgery; * Understand and agree to the research plan. Exclusion Criteria: * Patients with other diseases that may cause abnormal uterine bleeding (including endometrial polyps, endometrial hyperplasia, submucosal myoma, etc.) indicated by two-dimensional ultrasound * There are contraindications of surgery: such as severe internal and surgical complications, pregnancy, reproductive tract infection, malignant tumor;