Isthmotsele: modern aspects of diagnosis, therapy and prevention of complications (Literature review)

Worldwide there is an increased rate of caesarean section (CS), which leads to an growth in the percentage of intra- and postoperative complications compared to natural childbirth. One of such longterm complications after abdominal delivery is a scar defect on the uterus after SC (isthmocele).This literature review provides up-to-date scientific information on the etiology, risk factors, diagnosis, modern methods of correction and prevention of complications of this pathology.Isthmocele, by definition, is a scar defect after SC or a niche of the uterine wall, which has the appearance of a myometrial tear or a triangular anechoic defect of the anterior uterine wall, which can be classified as a small or large defect depending on the thickness of the residual (remaining) myometrium. Pathognomonic clinical symptoms are abnormal uterine bleeding, chronic pelvic pain, and infertility.In addition, pregnancy in the scar after SC, placenta previa or placenta accreta spectrum (PAS), rupture of the uterus in the area of the postoperative scar can be complications of this pathology during gestation.The main risk factors for isthmocele, proven to date, are previous SC and retroflexion of the uterus, and the influence of the technique of suturing the uterus during SC requires further research.In order to diagnose isthmocele and determine the thickness of the residual myometrium, transvaginal ultrasound, infusion sonohysterography with physiological solution, and magnetic resonance imaging are used.Treatment of isthmocele can be medical or surgical, depending on the size of the niche, the thickness of the remaining myometrium, the presence of symptoms and the woman’s reproductive plans. In case of refusal or contraindications to medical treatment, surgical correction of the isthmocele should be offered. Surgical treatment includes minimally invasive approaches using hysteroscopy, laparoscopy, or transvaginal techniques.Hysteroresectoscopy involves partial removal of the myometrium along the edges of the niche with coagulation of vessels. Therefore, this technique if the residual thickness of the myometrium is <3 mm should not be used in women who want to get pregnant. In these cases, myometrial repair is of primary importance and can be achieved by laparoscopic, laparotomy, or vaginal access. The review also provides information on the most serious complication of isthmocele – the development of a pregnancy in a scar/niche and modern approaches to managing such pregnancy.