Dynamic Observation Of Diverticulum Formation In Uterine Incision Under Hysteroscopy

Objective: To investigate the possible mechanism of abnormal uterine bleeding caused by uterine incision diverticulum by observing the formation of uterine scar diverticulum after cesarean section under hysteroscopy in different periods,so as to provide theoretical basis for improving the treatment of abnormal uterine bleeding caused by uterine incision diverticulum.Methods: The general clinical data of 12 patients with uterine incisional diverticulum diagnosed by vaginal ultrasonography and hysteroscopy were collected from the department of gynecology of the Affiliated Hospital of Zunyi Medical University from May 2020 to Dec.2020.These patients visited the department for treatment due to prolonged minor bleeding from vagina 2 to 3 months after cesarean section.Hysteroscopies were performed every 3 months and they were followed up for 9 months.The formation and morphological changes of uterine incision diverticulum were observed,and the mechanism of abnormal uterine bleeding induced by uterine incision diverticulum was studied based on its clinical manifestations and pathological characteristics of local tissues.Results: 1.In the early stage of diverticulum formation(2-3 months after cesarean section),the patients diagnosed as uterine diverticulum by transvaginal ultrasound and hysteroscopy usually presented depression-like structure at uterine incision,local tissue edema,with grayish white or yellowish white inflammatory necrotic tissue and bleeding spots,and no endometrial covering on the wound surface.2.After 5 to 6 months after cesarean section,the local tissue edema of the diverticulum disappeared,and the appearance of the diverticulum was scar-like.The surface of the diverticulum was covered with the thin endometrium,and the neovascularization on the surface of the endometrium was not obvious in the patients who have not regained menstruation;The surface of the diverticulum was covered with the thin endometrium,and fine neovascularization and oozing blood spots were faintly seen on the surface of the endometrium in the patients who have regained menstruation but complicated by abnormal uterine bleeding.3.About 8-9months after cesarean section,all the patients had scarred diverticulum,the orifice of diverticulum and the base of diverticulum were covered with endometrium,and there were neovascularization.The patients with abnormal uterine bleeding had abundant neovascularization on the surface of diverticulum,and all had neovascular oozing.4.After11-12 months of cesarean section,all the patients had a thin intima covering around the diverticular orifice and at the diverticulum base during the period of postmenstrual bleeding.The vascular hyperplasia on the surface of the intima was obvious,and the shapes were various,all of them had hemorrhage foci.5.The scar tissue of uterine diverticulum was mainly composed of fibrous connective tissue,which contained a little smooth muscle component,accompanied by surface vascular proliferation and lymphocyte infiltration.In a few patients,endometrial gland-like structure could be seen in the scar tissue of diverticulum.Conclusion: 1.The formation of uterine incision diverticulum is a gradual process,the weak diverticular structure formed by the tissue necrosis and inflammatory reaction at the initial uterine incision.With the disappearance of local inflammatory reaction and the scarring of local tissue,new endometrium and vascular hyperplasia appear on the surface of the diverticulum.2.Abnormal uterine bleeding after menstruation in patients with uterine incision scar diverticulum is caused by hyperplastic blood vessels on the surface of the diverticulum,and may be related to the asynchrony of the exfoliation of the diverticulum and the failure of the diverticular scar to form an effective hemostatic mechanism.A few patients are associated with ectopic endometrium in diverticulum of uterine incision.