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

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.

Keywords: fetal intervention; fetal renal function; fetal ultrasound; lower urinary tract obstruction (LUTO); prenatal diagnosis; prognostic staging systems.