Should the Triple-P Procedure be used as an Alternative to Peripartum Hysterectomy in the Surgical Treatment of Placenta Percreta?

Morbidly adherent placenta is an important cause of massive postpartum hemorrhage and is associated with increased maternal morbidity and mortality. Unfortunately, the incidence of morbidly adherent placenta is increasing worldwide and is believed to be due to the increasing rate of cesarean sections [1]. It is likely that scarring due to a previous cesarean section (or rarely, due to a previous traumatic uterine curettage and intrauterine sepsis) results in damage to the decidua basalis, which is the layer that is widely considered to act as a ‘barrier’ against deeper trophoblastic invasion. Hence, in the subsequent pregnancy, trophoblasts may invade through this deficient area, breaching the deciduo-myometrial interphase to reach the inner half of the myometrium (placenta accrete) or may penetrate deeper into the outer half of the myometrium (placenta increta). In severe cases, the placenta penetrates through the entire thickness of the myometrium and comes out of the uterine serosa (placenta percreta). Such a ‘perforating’ placenta is associated with serious maternal morbidity and mortality as the trophoblasts may not only invade adjacent organs (anteriorly into the urinary bladder, posteriorly into the colon and laterally into the broad ligaments and the ureters), but may also develop an additional blood supply from the blood vessels supplying these organs. Hence, removal of the placenta after birth is fraught with intentional and unintentional damage to surrounding organs, as well as difficulties in arresting an ‘ongoing’ massive obstetric hemorrhage due to multiple sources of blood supply, in addition to uterine arteries with traditional obstetric surgical procedures.

Management of morbidly adherent placenta involves anticipation (i.e., previous uterine surgery, traumatic curettage, uterine sepsis) and antenatal diagnosis using a high-resolution ultrasound scan with a color Doppler. A MRI scan is not routinely indicated for the diagnosis of anterior placenta percreta because a transabdominal high-resolution ultrasound scan with color Doppler provides sufficient information to aid diagnosis. However, in cases of posterior placenta percreta (where the fetal head may obscure the view) or lateral placenta percreta (possible invasion of the broad ligament or ureters), MRI scan may be very helpful in the diagnosis.

Once the diagnosis of morbidly adherent placenta is confirmed, a multidisciplinary team approach as well as the use of specific ‘care bundles’, as developed by the National Patient Safety Agency, may be useful in improving maternal outcome [2].

Placenta accrete and increta can be managed with multiple hemostatic sutures to the placental bed to arrest bleeding [3]. A peripartum hysterectomy may be considered either electively, if the woman has completed her family or as an emergency procedure, when conservative procedures have failed to arrest bleeding. However, this procedure is associated with increased maternal morbidity and mortality. It is worth noting that a 15-year analysis of peripartum hysterectomy reported that this procedure itself was associated with a maternal mortality rate of 12.5% and a urinary tract injury rate of 7.5% [4].

Placenta percreta is a serious and potentially fatal condition as the placenta perforates the uterine serosa and may invade adjacent structures. Although it accounts for only 10% of all morbidly adherent placentae, it causes more maternal morbidity (invasion into urinary bladder, bowel or ureters including fistulae or incontinence) and mortality due to uterine rupture or massive postpartum hemorrhage. Current management strategies for placenta percreta that invade adjacent organs include conservative surgical management to avoid separation of the placenta from its myometrial bed at the time of birth (‘intentional retention of placenta’), and radical surgery (peripartum hysterectomy with resection and repair of affected organs) with or without prophylactic uterine artery balloon catheter placement and/or embolization.

Conservative surgery involves incising the uterus above the upper placental border to deliver the fetus through a classical (usually a ‘fundal’) incision and clamping, cutting and ligating the umbilical cord very close to the placental surface (2–3 cm) and leaving the placenta in situ for spontaneous resorption. The main advantage of the conservative approach is the avoidance of massive postpartum hemorrhage at the time of delivery and its sequelae (i.e., multiple blood transfusions, transfusion-associated acute lung injury, coagulopathy, sepsis and multiorgan failure). However, leaving the placenta in situ may be associated with serious complications including secondary postpartum hemorrhage, disseminated intravascular coagulation and sepsis, all of which are potentially life-threatening. In addition, emergency hysterectomy and occurrence of ‘utero-cutaneous fistula’ have also been reported [5]. The conservative approach does reduce intraoperative and immediate postoperative complications, but it is associated with delayed, potentially fatal complications. Therefore, it requires intensive surveillance after discharge from hospital for 12–16 weeks to detect complications and hence, it is resource intensive. In addition, it requires patient compliance during follow-up.

The radical approach involves cesarean hysterectomy with resection of affected organs to remove invading trophoblasts and this may be performed as a planned procedure (i.e., ‘elective’) or as an emergency, when other surgical measures to arrest bleeding fail. According to the UK Obstetric Surveillance System on Morbidly Adherent Placenta, 39% of all peripartum hysterectomies were performed for this indication [6]. Ligation of internal iliac arteries or the use of interventional radiology (prophylactic placement of uterine artery balloon catheters, with or without embolization) may be used as adjuvants. The main advantage of peripartum hysterectomy is that it ensures removal of the adherent placenta at the time of delivery and if this is performed as an ‘elective’ procedure, the amount of intraoperative blood loss is also minimized, as no attempts are made at separating the morbidly adherent placenta from its underlying myometrial bed. However, as the placenta may derive its blood supply from adjacent organs into which it has invaded, bleeding may continue even after hysterectomy due to the secondary blood supply from these organs. Vaginal arteries may also feed a low-lying placenta from below and this may not be amenable to traditional internal artery ligation and/or interventional radiology techniques. Peripartum hysterectomy may also result in damage (intentional or unintentional) to adjacent organs (i.e., bladder, ureters and bowel) into which the placenta had invaded. This may result in increased morbidity and complications such as prolonged catheterization, ureteric stenting or re-implantation and prolonged hospital stay. Long-term implications include psychological effects owing to the loss of feminity.

The ‘Triple-P procedure’ for percreta has been developed as a conservative surgical alternative to peripartum hysterectomy [7]. Triple-P involves three steps: perioperative placental localization using a transabdominal ultrasound scan to delineate the upper border of the placenta on the operation table and delivery of the fetus through a uterine incision placed above the upper border of the placenta; pelvic devascularization immediately after delivery of the fetus by inflation of prepositioned uterine artery occlusion balloons to reduce blood supply to the myometrium and placental nonseparation and myometrial excision (to avoid separation of the morbidly adherent placenta from the underlying myometrial bed) with reconstruction of the uterine wall. The line of placental infiltration into the bladder is left untouched as attempts at separation may result in perforation of the urinary bladder. Myometrial excision has been previously described for morbidly adherent placenta [8,9]. However, avoidance of placental incision by delineating the upper border of the placenta immediately prior to cesarean section and immediate pelvic devascularization prior to myometrial excision helps minimize blood loss.

We initially reported this Triple-P procedure with four cases and have subsequently performed an additional four procedures, including one for placenta percreta at the site of resection of previous cornual ectopic pregnancy. In cases where there were no additional risk factors for postpartum hemorrhage such as uterine fibroids, blood loss during the procedure was <1 1. All patients were followed-up after 6 weeks and repeat serum β-human chorionic gonadotropin was undetectable and a transvaginal scan confirmed a normal uterine cavity. Hence, the Triple-P procedure appears to be a very effective alternative to peripartum hysterectomy, with minimum complications, in women with morbidly adherent placenta.

Potential drawbacks of the Triple-P procedure include technical difficulties with the placenta infiltrating the cervix and the broad ligament, where myometrial resection may not be possible. In addition, this procedure is not suitable for lateral placentae infiltrating the ureters. Although all our patients opted for peripartum sterilization, if future fertility is desired, concerns about possible uterine rupture and optimum timing of delivery remain. In low-resource countries, facilities for interventional radiology may not be available, but pelvic devascularization may still be carried out by uterine artery or quadruple ligation [3] and hence, the Triple-P procedure could still be a viable option.

The incidence of placenta percreta is reported to be rising and the impact of this ‘man-made monster’ is mainly felt by women who have suffered serious complications and families who have lost their loved ones due to massive postpartum hemorrhage and its sequelae. It is vital that our surgical techniques should also evolve to combat this potentially lethal ‘iatrogenic’ condition. The Triple-P procedure for percreta could be a useful weapon in an obstetrician's armamentarium and has the potential to be a conservative alternative to peripartum hysterectomy for a vast majority of women with an anterior placenta percreta infiltrating a previous cesarean section scar. Elective and emergency peripartum hysterectomy will still be required for some women with placenta percreta to save their lives, but hopefully, this number will gradually diminish in the future.