Introduction
In 1995, Morris first identified a poorly muscular healing scar on the
uterine incision, now called the previous cesarean scar defect (CSD), of
patients who developed postmenstrual abnormal uterine bleeding(PAUB)
after a cesarean section (C-section) (Figure 1A-1C). The incidence of
CSD ranges from 50% to 84% in random populations of women with a
history of cesarean section1.
Because many scholars consider that reducing the rate of the cesarean
section can reduce the occurrence of CSD, CSD has not received
widespread attention. However, women with CSD suffer from a series of
symptoms, all of which affect the patient’s quality of life. PAUB can
affect a couple’s sex life and the couple’s relationship. It can also
cause genital tract inflammation, vulva pruritus, and chronic abdominal
pain2,3. Additionally, with the implementation of China’s three-child
policy, women of childbearing age who have a history of C-section will
face subsequent pregnancy, and research has shown that CSD size and the
TRM are significantly correlated with subsequent infertility, it also
significantly reduces the success rate of frozen embryo transfer4-5. It
has also shows that CSD is associated with cesarean scar pregnancy,
placenta previa with placenta accreta, and even uterine rupture6,7.
The treatment approaches for CSD are usually divided into durgs and
surgery, but there are no treatment guidelines. Drugs mainly include
oral contraceptives, which can improve the symptom of PAUB during
medication, but it may relapse after stopping drugs8. Common surgical
procedures can be broadly categorized as reconstructive surgery and
surgery for improved PAUB symptoms. Reconstructive surgical techniques,
such as laparoscopic(LP)and vaginal repair(VR), involve isthmocele
resection and resuture. Surgery for improving PAUB symptoms, such as
hysteroscopic electroresection (HP), HP involves the removal of the
fibrous tissue flap from the bottom of the defect and cauterizes the
remaining scar tissue by using a wire loop9-11. Hysteroscopic resection
surgery can improve PAUB symptoms but will lead to thinning of the
myometrial tissue around the CSD, increasing the risk of the subsequent
pregnancy12. In patients with severe pelvic adhesions, attempt to repair
the CSD through vaginal surgery may be difficult in entering the
abdomen, leading to the risk of bladder injury or surgical failure. We
use vaginal repair assisted by single-port laparoscopy to reduce the
risk of bladder injury (Figure 1D, E, F). Therefore, a good preoperative
evaluation can help to formulate a more suitable treatment to improve
prognosis. It is particularly important to recognize that not all
diverticula require surgery and that not all surgeries can improve the
diverticulum.
Our surgical team has treated more than 1500 CSD patients from 17
provinces and cities across China, Australia, and the United States
since 2013. More than 1200 cases of CSD through VR have been
successfully carried out, and it is the largest CSD treatment cohort
known nationally and internationally.
Our previous study screened 607 women
with a history of C-section by transvaginal ultrasound(TVS) and found
that when the mean TRM is more than 5.39 mm, these women without PAUB
symptoms (menstrual durations less than 7 days) 14. This TRM size is
similar to that of Glavind’s study, whose research shows the TRM of 5.8
mm will be helpful for symptom control post-operatively13. According to
this result, we define a menstruation duration of no more than 7 days
and a TRM of no less than 5.39 mm after vaginal repair as optimal
healing.
Our previous studies indicated that CSD disappeared in 64.52% of CSD
patients after VR and that 60.0% of patients reached ≤7 days of
menstruation15. However, the factors affected healing were not defined,
so a model for predicting the outcome of repair surgery is urgently
needed. This study retrospectively analyzed 1015 cases of transvaginal
repair of CSD to develop a prediction model for the first time. The
findings of this study will be used to form an evidence-based proposal
for patient selection.