If the decision for a conservative treatment is made after surgical exploration, is image auxiliary diagnosis absolutely necessary? Yes, some features such as parametrial involvement, degree of lower uterus infiltration, and the presence of posterior invasion must be documented. Massive infiltration of lower uterus has been associated to unexpected and massive bleeding in conservative treatment (Figs. 13.2, 13.3, and 13.4).

If it exists, obstetricians need to consider practicing a planned hysterectomy in controlled conditions or operating on the patient during massive hemorrhage, which could significantly increase morbidity and mortality. Although these cases happened, unfortunately they were not published because of a death event. Other signs of uncommon involvement, such as parametrium [14] or posterior ones, can be analyzed with experts to provide the most accurate diagnosis to make decisions with informed consent.

Although retained placenta has many etiologies, the presence of undiagnosed AIP must always be considered [15] (Figs. 13.5 and 13.6a, b). As it was explained before, damage after abortion or curettage should be investigated in all cases [16]. If antecedent of abortion is confirmed and there is a problem to deliver the placenta, it is highly important to take all the measures to avoid additional tissue damage or/and unexpected bleeding.

Although accurate prenatal diagnosis made by a skilled ultrasound technician and pMRI studies is highly reliable, it is important to know that there is a possibility of false negative and positive cases [18, 19] (Figs. 13.7, 13.8 and 13.9).

In this respect, and due to the possible consequences of surgical treatment (bleeding, tissue damage, hysterectomy, etc.), we need to be cautious when first seeing that the incision does not agree with the prenatal diagnosis, because placental invasion might not be evident until bladder dissection is performed. Occasionally the baby is delivered through the fundal area, and after the absence of placental bleeding, the obstetrician decides to attempt to remove the placenta, because the anterior uterine wall appears to be normal. When the surgical exploration is not complete (posterior bladder wall), this maneuver is particularly dangerous and could end in a catastrophic and massive bleeding.

It is very important not to underestimate the possibility of unmanageable massive bleeding, because in some cases when the placenta is removed, the invaded uterus might break completely into two parts (even using gentle maneuvers), and uncontrollable bleeding may happen within few seconds [20].

It is highly recommendable to confirm the prenatal diagnosis by surgical exploration, especially before performing definitive maneuvers such as hysterectomy. Some experts avoid dissecting the bladder to reduce a possibility of damage and subsequent bleeding on the bulging area. Although the exact number of hysterectomies performed in normal implantation cases is unknown, it might be high when a definitive decision was only taken based on auxiliary diagnosis and on the first surgical view.

From a general point of view, it is not an acceptable practice to cross the placenta in certain or doubtful cases of AIP or to remove a high percentage of uterus with poor prenatal diagnosis or surgical appearance, which after pathological analysis might be normal.

Initial aspect in diagnosed cases is not always in agreement with the prenatal evaluation; for this reason, apparently normal aspect should never be underestimated [12] (Figs. 13.10, 13.11, 13.12, 13.13, 13.14, 13.15, and 13.16). The bladder, some tissue adhesions, or lower invasions (S2) could hide a classical aspect of AIP. When prenatal diagnosis is conclusive (US-pMRI), especially in patients with recognized antecedents of AIP, it is highly recommendable to finish the surgical exploration before confirming that it is a false positive case. It is mandatory to be completely sure that AIP is not present before making any attempt to remove the placenta.

Alternative treatments in AIP include resective ablative procedure, such as a hysterectomy, and conservative ones. Within the last group, there is a pure conservative treatment, in which the placenta is left in situ, and the conservative resective, in which the invaded area is resected and the placenta is extracted. All of them present advantages and disadvantages; their main features are presented on the following table.

In some countries, hysterectomy is the gold standard treatment for all types of AIP; however, this rule could end in unnecessary and definitive loss of possibility for gestation due to the false positive cases (Table 13.1). Contrary to what many people think, hysterectomy in AIP is not a simple procedure, which has high morbidity and mortality (Figs. 13.17a, b and 13.18). For this reason, hysterectomy is only recommended in centers with resources and a qualified team. When hysterectomy is started, generally, there is no possibility to turn back, especially because damaged tissue may start bleeding before it is separated from the uterus. Another problem is to find a dense adhesion with other organs, like the bladder. Upper bladder invasion is relatively easy to solve, but not the lower ones which can require special skills to be solved. Finally, undetected parametrial invasion might also be difficult to manage, especially when tissues are fragile or when they have vascular connections with the ureter or the pelvic wall. Most part of placental invasions (AIP) are linked with the uterine scar, so they are usually pelvisubperitoneal. This feature makes it necessary to manage the bladder, especially the posterior wall. Newly formed vessels among the placenta, the uterus, and the surrounding tissues are wide, fragile, and high flow; for this reason, the operator must be familiar with their management to practice the surgery. In summary, operators who perform a hysterectomy must be skilled and be able to manage a wide range of complications and variables [21, 22].