Comparison of Three Different Staging Systems Capable of Predicting the Severity of Congenital Lower Urinary Tract Obstruction (LUTO) and Its Prognosis - Review

Sep 29, 2026

Lower urinary tract obstruction (LUTO) is a rare but serious fetal condition linked to substantial morbidity and long-term renal risk. Although multiple prenatal staging systems have been developed to support management decisions and predict outcomes, their comparative prognostic performance remains unclear. This review critically evaluates three staging approaches used in clinical practice—those by Ruano, Fontanella, and Nassr—summarizing how each incorporates ultrasound findings, biochemical markers, and scoring to estimate severity and guide counseling.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages9

Reading Time23 min

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Introduction

Abstract

Review of Three Staging Systems

Journal of Clinical Ultrasound REVIEW OPEN ACCESS Comparison of Three Different Staging Systems Capable of Predicting the Severity of Congenital Lower Urinary Tract Obstruction (LUTO) and Its Prognosis Ugo Maria Pierucci1 | Irene Paraboschi2 | Matthieu Peycelon3 | Chryso P. Katsoufis4 | Alireza Alam5 | Gabriele Tonni6 | Mark D. Kilby7 | Gloria Pelizzo1,2 | Rodrigo Ruano8 1Department of Pediatric Surgery, Buzzi Children's Hospital, Milan, Italy | 2Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy | 3Department of Pediatric Surgery and Urology, National Reference Center for Rare Urinary Tract Malformations (CRMR MARVU), ERN eUROGEN Accredited Center, Robert-Debré University Hospital, APHP, GHU North, UMR INSERM 1141 NEURODEV, Université Paris Cité, Paris, France | 4Division of Pediatric Nephrology, University of Miami Miller School of Medicine, Miami, Florida, USA | 5Division of Pediatric Urology, Jackson Memorial Hospital, Miami, Florida, USA | 6Prenatal Diagnostic Centre, Department of Obstetrics and Neonatology, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Reggio Emilia, Italy | 7Birmingham Women's & Children's Foundation Trust and University of Birmingham, Birmingham, UK | 8Division of Maternal-Fetal Medicine, Department of Maternal and Fetal Medicine, Obstetrics and Gynecology, University of Miami, Miller School of Medicine, Miami, Florida, USA Correspondence: Rodrigo Ruano ([rodrigo.ruano@miami.edu](rodrigo.ruano@miami.edu); [rodrigoruano@hotmail.com](rodrigoruano@hotmail.com)) Received: 9 March 2025 | Revised: 24 June 2025 | Accepted: 13 August 2025 Funding: The authors received no specific funding for this work. Keywords: fetal intervention | fetal renal function | fetal ultrasound | lower urinary tract obstruction (LUTO) | prenatal diagnosis | prognostic staging systems ABSTRACT Lower urinary tract obstruction (LUTO) is a rare but severe fetal condition associated with significant morbidity and long-term renal risk. Several prenatal staging systems have been proposed to guide management and predict outcomes, yet their comparative prognostic value remains uncertain. This review provides a structured evaluation of three staging systems currently used in clinical practice: those proposed by Ruano, Fontanella, and Nassr. Ruano's system integrates detailed ultrasound findings and biochemical markers, providing explicit stage-specific management recommendations and guidance for specific prenatal therapy. Fontanella's approach depends solely on ultrasound parameters, specifically bladder volume and the gestational timing of oligohydramnios onset, without incorporating biochemical markers or offering clear treatment guidelines. Nassr's score employs both ultrasound and biochemical data within a numerical scoring framework, focusing primarily on identifying severe cases that might benefit from prenatal intervention. Each system has distinct strengths and limitations. Further multicenter validation studies are necessary to determine which staging system most effectively predicts clinical outcomes and optimally guides management for fetuses diagnosed with LUTO. 1 | Introduction Lower Urinary Tract Obstruction (LUTO) is a severe congenital anomaly associated with significant fetal morbidity and mortality (Haeri 2015; Pierucci et al. 2024) . It represents a diagnostic and therapeutic challenge, necessitating accurate and comprehensive staging systems to guide clinical management and predict outcomes (Farrugia 2020, 2016; Farrugia and | Gloria Pelizzo and Rodrigo Ruano contributed equally to this work and share last authorship. | | --- | | This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
© 2025 The Author(s). Journal of Clinical Ultrasound published by Wiley Periodicals LLC. | Journal of Clinica

FAQs

Why is prenatal staging important for congenital LUTO?

Prenatal staging is needed because LUTO shows marked phenotypic heterogeneity and inconsistent links between prenatal findings and long-term postnatal renal outcomes, making prognostication and counseling difficult.

What does the Ruano staging system incorporate?

Ruano’s system integrates detailed ultrasound findings with biochemical markers and provides explicit stage-specific management recommendations, including guidance for specific prenatal therapies.

How do Fontanella and Nassr staging approaches differ from Ruano?

Fontanella’s approach relies only on ultrasound parameters, including bladder volume and the gestational timing of oligohydramnios onset, without biochemical markers or clear treatment guidelines. Nassr’s score uses both ultrasound and biochemical data in a numerical framework, emphasizing identification of severe cases potentially benefiting from prenatal intervention.

Sep 29, 2026

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