Owing to the increasing number of deliveries via CS worldwide, subsequent complications associated with CS, such as prolonged menstruation, irregular genital bleeding, and secondary infertility, have become a considerable concern and treatment for these complications has drawn more and more attention. The association between the diverticulum and bleeding disorders is gradually revealed .
Currently, the two main treatment options include hormonal therapy and surgical repair of the diverticulum . Studies reported that CSD related menstrual bleeding disorders or cyclic pain do often not respond to hormonal therapies [8, 15]. Methods of operative repair of diverticulum include vaginal repair, laparoscopy, and hysteroscopy. The technique of defect repair through the hysteroscopy used in our clinic results in control of intermenstrual bleeding and pain control. One system review display that hysteroscopy is the most commonly reported approach for the revision of CSD and the existing evidence is inadequate to conclude that either hysteroscopy or laparoscopy is effective or superior to each other. However, hysteroscopy may have a potential risk of decreased resistance of the residual myometrial tissue at the level of the repair and furthermore may lead to uterine rupture during subsequent pregnancy [16, 17]
We believed that the choice of the surgical approach is mainly based on the clinical features of patients.In our population, all patients have no plans to conceive again and the residual myometrium thickness should not be less than 3 mm, given the anticipated risk on perforation or bladder injuries. Indeed, we only resected the distal rim of the defect to prevent proximal resection could harm the strength of the cervix and may induce unneeded cervical incompetence. Concurrently superficial coagulation of vessels in the niche aims at reducing blood loss from these fragile vessels.
Under this premise, the cure rate of CSD repair was 47.2% after 3 months, and 65.6% after 6 months in our study. However, the cure rate of CSD repair reportedly ranges between 54% and 84%,  varying considerably depending on the study. For example, Fabres et al. showed that 84% of CSD patients (20/24) were successfully treated by hysteroscopic surgery after a follow-up of 24 months . In the study of Wang et al., only 59.6% of patients (34/57) reported a postoperative improvement in symptoms after 3 months of surgery. The difference is mainly due to the absence of universal assessment criteria for CSD symptom improvement. Furthermore, data from one study showed that the intraoperative blood loss, operative time of hysteroscopy resection were (10.1±10.2 ml) and (20±5.6 min), lower than vaginal repair(P<0.05) and combined laparoscopic and hysteroscopy(P<0.05). The results of our study are similar to the above (intraoperative blood loss, 12.89±12.59 ml; operative time, 44.73±17.12 min). We and others assume that hysteroscopic resection is more cost-effective. Moreover, in our study, no major complications, such as massive bleeding or uterine perforation, were encountered during surgery.
Our study confirms that a higher number of previous CS is associated with poorly improved symptoms. In the studies cited[22, 23], the numbers of scar defects and large scar defects increase as the number of CS increases, the ultrasound examiner found that the more CS, the more difficult it was to evaluate the individual scars, and the number of scars seen at ultrasound imaging did not always correspond to the number of Cesarean sections in women who had undergone more than one Cesarean section. Not all CSD is likely treated completely, and this might explain why patients who had undergone≥2 CS were more likely to have no improvement compared with those who had one CS.
Clear and broad vision to ensure the successful hysteroscopic surgery of CSD, effective removal of the lower margin of the uterine diverticulum and intimal tissue in the incision is essential, hypertrophic endometrium can affect the surgical field of vision, at the same time, the endometrium is thin in the first half of the menstrual cycle due to hormones. Therefore, surgery should be performed in the first half of the menstrual cycle to ensure a clear view of the operation. Obstetrics and Gynecology of Chinese Medical Association Branch proposed the norm about gynecological hysteroscopy, and it suggests that Hysteroscopic surgery should be selected in the early follicular phase of the implementation, 21 which is convenient for operation because of broad vision. Our findings also confirm that poor outcomes were associated with a longer interval between the last menstrual period and the surgical treatment date (timing of surgery), this seems natural because the clear and broad vision of CSD surgery is likely to be an important factor affecting the improvement of postoperative symptoms. Taken together, these findings suggest that the timing of surgery may be an indicator of the incidence of incomplete relief of the performance of the menstrual cycle irregular menstruation after CSD repair.
The present study has several limitations. First, because our study was retrospective, CSD symptom relieve destination for patients was subject to selection bias and unmeasured confounding. This might include factors that determine the severity of CSD, technical factors and processes of surgery, and access to the Guangzhou Women and Children Medical Center, a tertiary obstetrics and gynecology hospital. Second, the small number size of the present study does not allow to extrapolate our findings to other population, and a proportion of patients were lost to follow-up at the 6th month, may lead to an underestimation of the improvement rate. Third, the parameter variables of CSD involved in our study were only the length, width, depth, and RMT, other parameters that may affect the prognosis are not fully considered. Final, the follow-up period (six months) might be too short to generalize our results to longer-term outcomes after CSD. But one recent study suggested that postoperative menstruation and imaging data did not differ markedly between 3 and 6 months after surgery, suggesting that follow-up at 6 months represents an adequate endpoint for evaluating the effectiveness of surgery.