Comprehensive surgical staging for placenta accreta spectrum

Objective: To analyze how precise the surgical staging is after prenatal diagnosis of patients with placenta accreta spectrum (PAS).

Material and methods: This was a retrospective cohort study that included 622 women diagnosed with placenta accreta spectrum who underwent surgery between 1 January 2000, and 1 January 2020, in public, private, and university hospitals in Buenos Aires, Argentina. Prenatal diagnosis included abdominal and transvaginal ultrasounds and T2-weighted MRI scans. Comprehensive surgical staging (CSS) was performed by dissecting the coalescence spaces of the pelvic fasciae, including the broad ligament and the colpouterine and retrouterine spaces. Once the compromised uterine wall (lateral, anterior or posterior) was identified, the characteristics of the lesion were evaluated. The lateral invasion was classified as type A when there was no placental tissue in the parametrial zone; type B when the placental tissue protruded laterally and was covered by serosa, and type C when the placental tissue included neoformed vessels. Involvement of the retrovesical space (anterior uterine wall) was classified as type A when no neoformed vessels and no firm adherence between nearby organs were present, type B when the retrovesical area partially adhered but the planes could be dissected, and type C when the lower dissection of the vesicouterine space was extremely adhered or impossible.The posterior uterine aspect was classified after exteriorizing the organ, with the placenta still inside. It was determined as type A when there was no evidence of placental invasion, type B when there was organ adherence or it showed a heterogeneous appearance of the posterior uterine wall above the peritoneal reflection, and type C when there was adherence to other organs or when the invasion or neovascularization was below the peritoneal reflection.

Results: CSS increases the efficacy of prenatal studies, including ultrasound and MRI, by up to 50%. The diagnosis of type 2 (parametrial) PAS or low retrovesical invasion implied an immediate modification of the surgical tactics, vascular control, or a specific type of surgery. Additionally, deep interfacial dissection allowed the identification of healthy uterine tissue, modifying the initial indication of hysterectomy for a conservative reconstructive procedure.

Conclusions: Comprehensive surgical staging of PAS proved to be an excellent tool for determining the extent and specific topography of placental invasion.