Clinical application of new classification of the calyx-pelvic system dilation UTD in children in a perinatal center

The aim of the study was to evaluate the clinical significance of the new urinary tract dilation classification (UTD-2014) in predicting outcomes of the calyx-pelvic system dilation detected by ultrasound (US) in children in the perinatal center.

Materials and methods. A retrospective analysis of the urinary system ultrasound protocols and the outcomes of 152 children with dilated calyx-pelvic system due to various causes examined at the National Medical Research Center for Obstetrics, Gynecology and Perinatology for the period from 2017 to 2022 was carried out.

Results. The median age of patients at the time of the first ultrasound was 2 days, the median duration of follow -up was 10 months. The decrease in the UTD category during the observation period occurred in –/35/29/10% of patients in groups with the primary established UTD category 0/I/II/III, respectively. The UTD category remained the same in 42%, an increase in the category occurred in 32/26/4/-% of patients with UTD 0/I/II/III, respectively. The age at the time of the first ultrasound of patients who had an increase in the UTD category (median – 2 (1; 3.5) days) was significantly less than in other children (with the exception of operated patients). Surgical intervention was performed by 0/2/31/60% of patients with UTD category 0/I/II/III (only 18%), respectively.

Conclusions. UTD classification correlates well with outcomes of the calyx-pelvic system dilation due to various causes in children – the larger the category according to primary ultrasound, the less often its decrease or lack of dynamics is noted during follow-up, surgical treatment is more often necessary. When using the UTD classification in the perinatal center, there is a high risk of underestimating the degree of dilatation due to the early conduct of the first ultrasound in the first two days of life.

1. Geldt V.G., Kuzovleva G.I. Diagnosis of the urinary system malformations in newborns and infants. Pediatrics. Journal named after G.N. Speransky. 2006; 85 (1): 87–94. (In Russian)

2. Malformations of the urinary system. Chapter 40. In: Neonatal surgery / Eds Yu.F. Isakov, N.N. Volodin, A.V. Geraskin. M.: Publishing House “Dynasty”, 2011: 598–638. (In Russian)

3. Nguyen H.T., Benson C.B., Bromley B. et al. Multidisciplinary consensus on the classification of prenatal and postnatal urinary tract dilation (UTD classification system). J. Pediatr. Urol. 2014; 10 (6): 982–999. https://doi.org/10.1016/j.jpurol.2014.10.002

4. Nguyen H.T., Phelps A., Coley B. et al. 2021 update on the urinary tract dilation (UTD) classification system: clarifications, review of the literature, and practical suggestions. Pediatr. Radiol. 2022; 52 (4): 740–751. https://doi.org/10.1007/s00247-021-05263-w

5. Fernbach S.K., Maizels M., Conway J.J. Ultrasound grading of hydronephrosis: introduction to the system used by the Society for Fetal Urology. Pediatr. Radiol. 1993; 23 (6): 478–480. https://doi.org/10.1007/BF02012459

6. Onen A. An alternative grading system to refine the criteria for severity of hydronephrosis and optimal treatment guidelines in neonates with primary UPJ-type hydronephrosis. J. Pediatr. Urol. 2007; 3 (3): 200–205. https://doi.org/10.1016/j.jpurol.2006.08.002

7. Riccabona M., Avni F.E., Blickman J.G. et al. Imaging recommendations in paediatric uroradiology: minutes of the ESPR workgroup session on urinary tract infection, fetal hydronephrosis, urinary tract ultrasongraphy and voiding cystourethrography. Barcelona, Spain, June 2007. Pediatr. Radiol. 2008; 38 (2): 138–145. https://doi.org/10.1007/s00247-007-0695-7

8. Levitskaya M.V., Menovshchikova L.B., Golodenko N.V. et al. Diagnostic algorithm in infants with antenatal pyelectasia. Pediatric Surgery. 2012; 1: 7–11. (In Russian)

9. Kadioglu A. Renal measurements, including length, parenchymal thickness, and medullary pyramid thickness, in healthy children: what are the normative ultrasound values? Am. J. Roentgenol. 2010; 194: 509–515. https://doi.org/10.2214/AJR.09.2986

10. Melo F.F., Vasconcelos M.A., Mak R.H. et al. Postnatal urinary tract dilatation classification: improvement of the accuracy in predicting kidney injury. Pediatr. Nephrol. 2022; 37: 613–623. https://doi.org/10.1007/s00467-021-05254-x

11. Hodhod A., Capolicchio J.P., Jednak R. et al. Evaluation of urinary tract dilation classification system for grading postnatal hydronephrosis. J. Urol. 2016; 195 (3): 725–730. https://doi.org/10.1016/j.juro.2015.10.089

12. Braga L.H., McGrath M., Farrokhyar F. et al. Association of initial society for fetal urology grades and urinary tract dilatation risk groups with clinical outcomes in patients with isolated prenatal hydronephrosis. J. Urol. 2017; 197 (3, Pt 2): 831–837. https://doi.org/10.1016/j.juro.2016.08.099

13. Braga L.H., McGrath M., Farrokhyar F. et al. Society for Fetal Urology Classification vs Urinary Tract Dilation Grading System for prognostication in prenatal hydronephrosis: a time to resolution analysis. J. Urol. 2018; 199 (6): 1615–1621. https://doi.org/10.1016/j.juro.2017.11.077

14. Nelson C.P., Lee R.S., Trout A.T. et al. The association of postnatal urinary tract dilation risk score with clinical outcomes. J. Pediatr. Urol. 2019; 15 (4): 341.e1–341.e6. https://doi.org/10.1016/j.jpurol.2019.05.001

15. Bratina P., Kersnik Levart T. Clinical outcome is associated with the Urinary Tract Dilation Classification System grade. Croat. Med. J. 2020; 61 (3): 246–251. https://doi.org/10.3325/cmj.2020.61.246