In cases of PP where the placenta covers the lower uterine segment, it may be necessary to cross the placenta to deliver the baby. In addition, due to the poor contractility of the lower uterine segment and because of the increased blood supply, this manoeuvre usually produces additional haemorrhage. If the bleeding is not controlled, the process may be aggravated and end in coagulopathy or other severe complications [
11]. On the other hand, in this serious condition, it is necessary to deliver the baby quickly and control the haemorrhage to avoid shock and coagulopathy. This is not a minor issue, especially when the response time is short [
12].
There is no current universal treatment for PP. Management could be different according to personal or maternal preferences and medical experiences, skills and resources. Although, several approaches are available, all aim to avoid maternal bleeding during delivery [
13]. PP can be managed conservatively without hysterectomy in the following two ways: (i) leave the placenta in situ and (ii) partial myometrial resection of the entire placenta and restoration of the uterine anatomy. Each method has weaknesses and strengths. The major advantage of myometrial resection is that it allows for pathological confirmation of PP [
12].
Palacios et al. published the largest series on the conservative treatment of PP worldwide [
5]. A uterine incision was usually located in the upper section of the involved segment, and the trans-placental approach was recommended, when possible. Haemostasis was achieved with additional surgical procedures, such as selective vascular ligatures of the large vessels, and additional coagulant materials, such as fibrin glue and polyglycolic mesh. They performed an antero-posterior fundal extra hysterotomy (DI) to extract the foetus when segmental dissection was not feasible due to tissue fusion of the involved areas. The success rate was 50/68 (73.53%) in this case series. Our study is the first to compare DI and SI via the trans-placental approach in uterus-preserving surgery for PP.
DI was based on the following three aims:
1-
Safe extraction of the foetus, decreasing time loss during vesico-uterine dissection and damage to the foetal-placental circulation
2-
Reduce blood loss due to the incision adjacent to pathologically adhesive placenta
3-
Easily change the surgery type to hysterectomy, if necessary.
The dissection of the vesical-uterine fold should be performed before extraction of the foetus in SI. Bladder invasion is a severe complication of PP. Abnormal blood supply of invaded tissue, adhesions, a narrow operating space and a lack of dissection planes may make this surgery exceedingly difficult for the surgeon. The dissection is processed step by step with ligation through neoformation of vessels and might take a long time and substantial effort. The DI technique first aims to protect the foetus from the time loss during vesical-uterine dissection. Because of the propensity for severe haemorrhage, almost all patients with PP undergo general anaesthesia. In a previous study, it was shown that induction-to-delivery intervals of more than eight minutes and uterine incision-to-delivery intervals of more than three minutes were associated with a greater incidence of low Apgar scores and significantly more instances of neonatal acidosis [
14]. The severity of adhesion is usually established when attempts are made to separate the adherent placenta from the bladder. This manoeuvre can cause massive haemorrhage that is often quite challenging to control [
15]. The best procedure must protect the foetus from massive haemorrhage and avoidable complications during delivery. The second incision is far from invasive, and adhered placenta could protect the foetus from the negative effects of massive bleeding due to the dissection. Extraction of the foetus might enhance vision in the area of the operation. Moreover, the surgeon could more calmly concentrate on the placenta dissection. Caesarean hysterectomy with a PP in situ is clearly more difficult than other elective caesarean hysterectomies [
16]. There is a greater need to both maintain a margin from the vascular cervical-placental mass and protect the ureters and vesical. The region of PP will most often involve the lower uterine segment and mid posterior fundus of the bladder. It is important that the uterus is devascularized as much as possible before this region is approached [
17]. DI should give surgeons sufficient time for segmental resection, and all of these interventions might be performed to prevent massive haemorrhage.
We compared results of segmental resection via SI or DI. The characteristics of the cases, such as the ages, gravidas, numbers of previous caesarean deliveries, and gestational ages on delivery, were similar. Five of the 10 cases in the SI group underwent operations in emergency conditions, and the skin incision was the Pfannenstiel incision in four of these cases. Only two cases with DI had surgeries in emergency conditions. An infra-umbilical midline incision was markedly more common in DI (10 of 12) compared to in SI (two of 10 cases). We chose the type of skin incision because of the individual risk of cases. In cases with a high risk for wide invasion, which had anterior placental placement and dense, widespread invasion, the skin incision was planned as an infra-umbilical midline incision. This method prevented unnecessary infra-umbilical midline incisions. These findings support our success with pre-operative foresight. In high-risk patients, we preferred an infra-umbilical midline incision before surgery, and these patients underwent segmental resection with DI after laparotomy. On the other hand, there might have been a potential selection bias in our study because it was retrospectively designed, even though the data were prospectively collected.
Although DI was applied to patients who had a high risk of wide invasion, we have seen that DI did not extend the operation time. No study has discussed blood loss or the need for transfusion based on focusing on PP cases who were treated conservatively. Wright et al. examined predictors of blood loss for women with placenta accreta who had undergone hysterectomy [
18]. The median estimated blood loss was three litres, and the mean transfusion requirement was five units. In our study, the median transfusion requirements were three units in the SI group and four units in the DI group. There was no statistically significant difference. A patient underwent re-laparotomy in response to disrupted haemodynamics in the 15
th hour of operation, with suspicion of intra-abdominal bleeding, and received 13 units of packed red cells. When we excluded this case, the median transfusion requirement was 2 units. SI or DI did not change the number of days spent in the intensive care unit or hospital. Additionally, the success rate of conservative surgery was not different between SI and DI.
Reported complications in the conservative surgery of PP included venous haemorrhage, rupture of an epigastric artery and disseminated intravascular coagulation. Ureteral lesions, simple vesical fistula, iatrogenic foreign body and uterine infection with anaerobic gram-negative bacteria were reported in previous studies [
5,
19]. We observed mild disseminated intravascular coagulation in one patient. This patient underwent re-operation, and we performed hysterectomy. We have not observed any vesical injury in our case series. We thought that this could be due to the effect of filling the bladder before dissection of the retro-vesical space. This method helps the surgeon identify the borders of the bladder and neoformation vessels. However, this issue requires support from further studies. There was a urinary system infection in one patient in each group, and the patients were treated with appropriate antibiotics.
Long-term complications are a constant source of concern in the conservative management of PP. Palacios et al. reported on 10 pregnancies in 42 patients who were followed up for 3 years after surgery [
5]. They did not observe any complications during the pregnancies, and vesical and segmental dissection were easily performed in all of them. DI could improve the risk of uterine rupture; however, this hypothesis needs to be tested with long-term follow-up studies. It has been reported that there is an approximate 22-28% recurrence risk of PP when patients undergo conservative management and have a subsequent pregnancy [
20,
21]. This risk should be discussed with women who have an antenatal diagnosis of PP and who may be considering conservative treatment.
We acknowledge the limitations of this type of case series report and the susceptibility to bias. However, it is clinically challenging to perform a study with large cohorts on such a rare condition.