Objective: The postmenstrual bleeding with cesarean-induced diverticulum is a bothersome symptom and can be confused with other abnormal-uterine bleeding disease. The aim of the present study was to evaluate the efficacy and safety of laparoscopic combined with hysteroscopic repair vs operative hysteroscopy in treatment of symptomatic cesarean-induced diverticulum.

Methods: Eighty-two women with cesarean-induced diverticulum who underwent either laparoscopic combined with hysteroscopic repair or operative hysteroscopy between January 2012 and September 2015 were retrospectively included in the study. We evaluated the menstrual duration before and after the surgery, the width, length and depth of the niche, operating time, blood loss, complications, and postoperative pregnancy status.

Results: 62.2% (51/82) patients started to have postmenstrual bleeding immediately when they gained regular menstruation after their cesarean section. The laparoscopic group has longer operative time and greater blood loss (p<0.001). Both groups have a significant improvement in their menstruation duration ( p< 0.001). The patients in the laparoscopic repair group had a greater improvement in bringing the uterine bleeding into normal menstruation duration (P=0.046) and the same in pregnancy rate (P=0.505). The interval between operation and pregnancy in laparoscopic combined with hysteroscopic group was much longer than the hysteroscopic group (27 vs 10 months, p<0.001).

Conclusion: the laparoscopic repair exhibited a better efficiency in bringing the uterine bleeding into normal menstruation duration and in improving the pregnancy rate However, there was not a clear absolute advantage for one of the two type of surgeries. Thus, patients with post-cesarean section diverticulum (PCSD) should choose with caution the type of surgery, considering the residual myometrial thickness (RMT), the age, the desire for further fertility and ovarian reserve capacity.

The number of deliveries by cesarean section has been increasing steadily worldwide in recent decades, especially in China. It has been reported that half of the deliveries in 2010 were by cesareans [1] despite the short-term risks such as an increased blood loss, the high risk of infection and the thromboprophylaxis [2, 3]. Cesarean section carries long-term sequelae, which can adversely affect subsequent pregnancies. In a recent study, 64.5% of patients who underwent cesarean section developed uterine incision diverticulum within 6 to 12 weeks after surgery, which can cause abnormal uterine bleeding. Women with a single caesarean section had a 62% risk of developing niche, compared with 68.2% of women with two caesarean sections and 77.8% of women with three-times caesarean sections [4]. However, the syndrome often confuses with other uterine diseases. Some inexperienced doctors, especially from the underdeveloped communities hardly notice this defect. Currently, the treatment of this diverticulum may be performed by laparoscopic, combined laparoscopic vaginal surgery or vaginal surgery and operative hysteroscopy, transabdominal or transvaginal, all minimally invasive approaches to improve symptoms and restore fertility [5, 6]. However, there is no guideline to indicate which technique should be selected. In the present study, the diagnosis and the prevalence of associated symptoms will be reviewed; how the various surgical approaches (hysteroscopic or laparoscopic) may improve clinical problems related to cesarean section scar will be also discussed.

The defects in cesarean section scars are common [7]. The prevalence of caesarean scar diverticulum was found to vary between 56% and 84% according to a published study [8]. As not all women with an history of cesarean section develop a diverticulum, it is of interest to identify the symptoms that may predict them. There is growing interest in possible associations between the presence of a niche and various gynecological symptoms, and in the mechanisms behind the development of these symptoms. Among women with cesarean scar defect, abnormal uterine bleeding, a common symptom reported to be associated with the presence of ache, was found in 28.9-82% of cases [9]. The most typical and bothersome symptom is postmenstrual bleeding (all our cases) characterized by the discharge of a dark hematic material collected in the scar pouch during the days after menstruation. The bloody fluid retention which is due to the atypical anatomical defect and the hemorrhage from the scarred area can be the cause of this syndrome. It has been reported that one out of three women with a niche has a abnormal menstrual bleeding, compared with one out of ten women without a niche. The syndrome occurs one year after caesarean section was strongly related to the presence of a niche [4]. Our result shows that 62.2% (51/82) patients start having postmenstrual bleeding immediately when they gain regular menstruation after their cesarean section. The defect of cesarean scar has been reported to be as high as 24% to 64.5% in women, 6 to 12 weeks after cesarean section [4, 8]. Due to breast-feeding, part of the women gain their menstruation after the cesarean section diverticulum is formed. The bloody fluid retention which is due to the atypical anatomical defect can be the cause of what was found herein. Wang C.B [10] believes that the size of the cesarean scar defect is associated with postmenstrual bleeding. van der Voet [4] found that postmenstrual spotting was related to a residual myometrium: women with residual myometrium at the site of the uterine scar measuring <50% of the adjacent myometrial thickness had postmenstrual spotting more often than women with a residual myometrial thickness >50% of the adjacent myometrial thickness. In our study, we have not started measuring the residual myometrium vs the adjacent myometrial thickness. However, there was no correlation between the length, width or depth of the diverticulum and the length of patient menstrual periods. The postmenstrual bleeding of cesarean section diverticulum may have multiple physiopathologic mechanisms along with an atypical anatomy that requires further randomized research.

The surgical treatment of symptomatic women with cesarean scar defect is the partial resection of scarring by hysteroscopy and complete resection of the scar tissue, the suture of the healthy tissue through abdominal or through vaginal surgery. To date, there are no guidelines for the selection of operative strategies for this defect. Some reports have cited an RMT of <2mm as a rough indicator of the risk of uterine rupture during a trial of labor after cesarean delivery [11, 12]. Furthermore, a RMT of <2mm has been shown to increase the risk of uterine rupture and bladder injury during hysteroscopic surgery [13]. Satoshi Tanimura used RMT and the position of the uterus as criteria for the selection of surgery to treat cesarean scar defect and showed that hysteroscopic surgery is only indicated for women with an RMT of ≥2.5mm [14]. But in the present study, there are 25 RMT in the hysteroscopic group <2mm and no significant difference between the two group. None of the 82 patients got uterine rupture, bladder injury and infection. Thus, we assume that the RMT is not the essential criteria selection of surgery. The limited operative time and the surgical proficiency can help to eliminate the risk.

Due to the short operative time and the smaller loss of blood, operative hysteroscopy can be performed if the adjacent myometrium exists and is continuous. However, whether the myometrium can bear the pregnancy remains unknown. In the present study, we performed the Laparoscopic Repair when the patient RMT was <1mm, with the intention of a future pregnancy.

The clinical efficacy of these two types of surgery varies according to different articles. It has been reported that the hysteroscopic repair of cesarean scar defect is associated with an improvement in uterine bleeding in 59% to 100% of cases and the pregnancy rate in 77.8% to 100% of cases. Improvement in uterine bleeding after vaginal repair occurs in 89% to 93.5% of cases. Laparoscopic repair leads to uterine bleeding improvement in 86% of cases, with a pregnancy rate of 86% [9]. In our finding, the laparoscopic repair was more efficient in bringing the uterine bleeding into a normal menstruation duration and similar in the pregnancy rate. In China, we recommend that women have at least a one year inter-pregnancy interval after cesarean section. We favor the same interval for women after laparoscopic repair and 3 months for the hysteroscopic repair, the laparoscopic repair having a much longer contraceptive time than the hysteroscopic repair, which may affect the pregnancy rate due to our short observation time. In our opinion, women with advanced age (>40 years) or women with lower ovarian reserve capacity are not suitable for laparoscopic repair. If a patient with an advanced age and a RMT <1mm still has plan for a further pregnancy, she should be fully informed of the consequence and choose the operation with caution. An oocyte retrieval should be done before the laparoscopic surgery to preserve the fertility. To date, it has been reported that postoperative menstruation and imaging data did not differ significantly between 3 months and 6 months after vaginal repair, suggesting that follow-up at 3 months represents an adequate endpoint for evaluating the effectiveness of surgery [15]. This may be an indication that there is still a space for shortening the contraceptive time for the women who underwent laparoscopic repair.

The limitations of the current study include its retrospective nature, its limited sample size. Moreover, we did not examine the nidus size after the surgery to evaluate the efficacy of the methods. A large, randomized controlled trial and a longer follow-up period are needed to verify our findings.

Postmenstrual bleeding occurred immediately when the patient gained regular menstruation after the cesarean section suggested the existence of a cesarean section diverticulum. As the two type of surgeries can be still envisionned, patients with PCSD should choose with caution the method to be used, considering the RMT, the age, the desire for further fertility and the ovarian reserve capacity. However, the hysteroscopic repair may be a more suitable choice in a number of patients.

The authors have no conflict of interest to declare.

This investigation was supported by the construction project of clinical specialty in Fujian Province (project No. 2012149).