Beyond POP-Q: A Scoping Review of Pelvic Floor Ultrasound for Anatomical Phenotyping of Anterior Compartment Prolapse

Background/Objective: Anterior compartment prolapse is commonly described as cystocele or anterior vaginal wall descent, although these terms do not identify the underlying mechanism of support failure. Similar POP-Q findings may result from different anatomical defects, including central cystocele, paravaginal support loss, apical descent, levator ani injury, hiatal ballooning, or combined abnormalities. Pelvic floor ultrasound may improve anatomical characterization, but its role in defect-specific phenotyping remains unclear. Our objective was to map the current evidence on the use of pelvic floor ultrasound for anatomical phenotyping of anterior compartment prolapse beyond POP-Q staging. Methods: A scoping review was conducted according to PRISMA-ScR guidelines. PubMed/MEDLINE, Scopus, and Web of Science were searched through May 2026. Studies evaluating anterior compartment prolapse using pelvic floor ultrasound were included. Non-ultrasound anatomical, clinical, and MRI studies were considered only as contextual literature and were not included in the evidence synthesis. Results: Twelve ultrasound-based studies were included. Most studies focused on lateral/paravaginal support abnormalities, while fewer investigated central cystocele configuration, apical-related anterior prolapse, levator-related abnormalities, and hiatal ballooning. Ultrasound techniques were heterogeneous and included transabdominal, introital, transvaginal, and translabial/transperineal approaches, frequently using three-dimensional and four-dimensional imaging. Conclusions: The available evidence suggests that anterior compartment prolapse represents a heterogeneous anatomical condition rather than a single entity defined by POP-Q descent alone. Pelvic floor ultrasound may complement clinical examination by providing dynamic information on different components of anterior compartment support, including cystocele configuration, levator ani integrity, and hiatal dimensions. However, the clinical interpretation of several phenotypes remains limited by heterogeneous terminology, variable imaging protocols, and the lack of standardized diagnostic criteria, particularly for paravaginal defects and the apical contribution to anterior wall descent. Future research should focus on harmonized ultrasound definitions, reproducible acquisition protocols, and prospective validation against anatomical and clinical outcomes to determine the role of ultrasound-based phenotyping in individualized management.