ORIGINAL RESEARCH published: 12 April 2021 doi: 10.3389/fped.2021.646517 Hydronephrosis Classifications: Has UTD Overtaken APD and SFU? A Worldwide Survey Santiago Vallasciani 1*, Anna Bujons Tur 2 , John Gatti 3 , Marcos Machado 4 , Christopher S. Cooper 5 , Marie Klaire Farrugia 6 , Huixia Zhou 7 , Mohammed El Anbari 8 and Pedro-José Lopez 9,10 1 Division of Urology, Department of Surgery, Sidra Medicine, Doha, Qatar, 2 Division of Pediatric Urology, Puigvert Foundation, Barcelona, Spain, 3 Division of Pediatric Urology, Children’s Mercy Hospital, Kansas City, MO, United States, 4 Division of Pediatric Urology, University of São Paulo, São Paulo, Brazil, 5 Department of Urology, University of Iowa Hospitals and Clinics, Iowa City, IA, United States, 6 Division of Pediatric Urology, Chelsea and Westminster Hospital NHS Foundation Trust, London, United Kingdom, 7 Department of Pediatric Urology, Bayi Children’s Hospital, Affiliated of the Seventh Medical Center of PLA General Hospital, Beijing, China, 8 Division of Clinical Informatics, Sidra Medicine, Doha, Qatar, 9 Hospital Exequiel Gonzalez Cortes & Clinica Alemana, Santiago, Chile, 10 University of Chile, Santiago, Chile Edited by: Venkata R. Jayanthi, Nationwide Children’s Hospital, Objective: To collect baseline information on the ultrasonographic reporting preferences. United States Reviewed by: Method: A 13-multiple choice questionnaire was designed and distributed worldwide Onur Telli, among pediatric urologists, pediatric surgeons, and urologists. The statistical analysis Istanbul Kartal Dr. Lutfi Kirdar of the survey data consisted of 3 steps: a univariate analysis, a bivariate and a Education and Research Hospital, Turkey multivariate analysis. John Samuel Wiener, Results: Three hundred eighty participants responded from all the continents. Duke University, United States The bivariate analysis showed the significant differences in the geographical area, *Correspondence: Santiago Vallasciani the years of experience and the volume of cases. Most of the physicians prefer santiago.vallasciani@gmail.com the SFU and APD systems because of familiarity and simplicity (37 and 34%, respectively). Respondents noted that their imaging providers most often report findings Specialty section: This article was submitted to utilizing the mild-moderate-severe system or the APD measurements (28 and 39%, Pediatric Urology, respectively) except for North America (SFU in 50%). Multivariate analysis did not provide a section of the journal Frontiers in Pediatrics significant differences. Received: 27 December 2020 Conclusion: Our study evaluates the opinions regarding the various pediatric Accepted: 23 February 2021 hydronephrosis classification systems from a large number of specialists and Published: 12 April 2021 demonstrates that there is no single preferred grading system. The greatest reported Citation: Vallasciani S, Bujons Tur A, Gatti J, shortcoming of all the systems was the lack of universal utilization. The observations Machado M, Cooper CS, taken from this study may serve as basis for the construction of a common worldwide Farrugia MK, Zhou H, El Anbari M and Lopez P-J (2021) Hydronephrosis system. As APD and SFU are the preferred systems and the UTD a newer combination of Classifications: Has UTD Overtaken both, it is possible that with time, UTD may become the universal language for reporting APD and SFU? A Worldwide Survey. hydronephrosis. This time, based on the result of this survey, seems not arrived yet. Front. Pediatr. 9:646517. doi: 10.3389/fped.2021.646517 Keywords: hydronephrosis, classification, survey, pediatric urology, ultrasound, pediatric radiology Frontiers in Pediatrics | www.frontiersin.org 1 April 2021 | Volume 9 | Article 646517 Vallasciani et al. Hydronephrosis Classification Preferences Worldwide Survey INTRODUCTION (Sociedad Iberoamericana de Urologia Pediatrica, Argentinian, Chilean, and Brazilian Society for Pediatric Urology). The Ultrasound reports serve as an instrument to communicate Society for Fetal Urology advertised it through their members. anatomic findings to health care providers permitting the Colleagues in China had an alternative link to the same survey patient’s physician to make therapeutic decisions and counsel through SurveyMonkey(R). Duplicate respondents were avoided families. In the specific case of hydronephrosis, the report can as these survey platforms identify the respondent before allowing be generated from the maternal-fetal specialist in the prenatal them to submit the survey. A secondary assessment of potential period or the pediatric radiologist postnatally. To communicate duplicated responses was performed manually by the authors the results of the ultrasound study reliably and accurately, reviewing case by case the answers. several classifications have been developed. Initially the anterior- The statistical analysis of the survey data consists of 3 steps: a posterior diameter of the renal pelvis (APD) was developed. univariate analysis by providing the frequencies and representing Subsequently, additional systems that included other anatomical graphically each variable alone; a bivariate analysis by measuring details regarding the calyces, renal parenchyma, ureters, and/or dependence of each variable from a first group with each variable bladder were developed. These classification systems included from a second group, this is done using a G-test which is more the Society of Fetal Urology (SFU), Onen, UTD (Urinary general than a chi-square test; and a multivariate analysis using Tract Dilatation), and European Society of Pediatric Radiology Multiple Correspondence Analysis (MCA) to form groups of the system (ESPR). surveyed people depending on their answers to all the questions. To date, there is no clear consensus on which of these All the statistical analyses are performed using the R statistical systems offer better categorization of the dilatations, the best software version 3.5.0. inter/intra-rater reliability, or the best prognostic value at the time of its assessment in cases of suspected or diagnosed urinary tract obstruction or vesicoureteric reflux. Even among pediatric RESULTS urologists and surgeons, the individuals who will utilize these reports to make therapeutic and surgical decisions, no apparent Three hundred and eighty physicians participated to the consensus exists on which system is preferable. To advance questionnaire. The univariate analysis results are depicted in the communication and subsequent research in this area, a clear Figures 1, 2. consensus among pediatric urologists regarding the preferable Globally, the two most preferred systems were the SFU system system for categorization and reporting of hydronephrosis and the renal Pelvic AP diameter with 37 and 34%, respectively is needed. (140/380 and 129/380). The more recently developed UTD We hypothesize that there is no single preferred system ranked third in terms of overall preference with 18% hydronephrosis grading system among pediatric surgeons choosing it as their preference. A minority of participants (8%) and urologists. The aim of this study was to collect choose the mild-moderate-severe system and only 1% chose the baseline information on the ultrasonographic reporting Onen or the ESPR system (Figure 2, right). preferences among pediatric urologists and surgeons evaluating The classification systems most utilized by providers was hydronephrosis and correlate it with the reporting system based on an open question (question 11) that permitted the utilized in their localities. participant to choose more than one classification system. Globally there were 601 responses to this question, averaging nearly 2 study systems per respondent. This resulted in an MATERIALS AND METHODS increase of the popularity of the mild-moderate-severe (28%) and a net reduction on SFU and UTD (25 and 7). The Pelvic AP A 13-multiple choice questionnaire was designed by the authors diameter was slightly increased (39%) while the Onen and ESPR (Appendix 1 in Supplementary Material). It was comprised remained uncommon (0.3 and 1%) (Figure 2, left). of 4 questions on surgical specialty and type of practice, 4 The bivariate analysis (Table 1) showed significant differences on classification preferences, 3 related to communication with in the type of responses. Three main variables affected these report providers, and 2 on future perspectives (Appendix 1 in differences: The geographical area for favorite classification Supplementary Material). system, communication with providers, system used by providers Institutional Review Board of the Institution of the first author and attempt to build a common system, the years of experience waived the review by them as considered not a requirement for attempting to build a common system and willingness to change the present research. The participation of the responders was the preferred system, and the volume of cases per provider. voluntary and considered as consent. The responders were also There were significant differences in preferred grading system able to decide whether to provide their names and email contact related to the geographical area (Supplementary Table 1). Asia, or remain anonymous. Europe and Oceania prefer the Pelvic AP diameter (47, 45, and From November 2018 to February 2019, the questionnaire 57%) whereas Middle East/North Africa and North America was accessible online through GoogleForm(R) platform and prefer the SFU system (63 and 59%). South America did not publicized through mailing lists (peds-urology@lists.it.uab.edu, show a marked difference among the Pelvic AP diameter and novo-uroped@googlegroups.com, European Society for Pediatric SFU (38 and 30%). Within geographic areas, there were major Urology roster members database) and social media groups differences in communication with providers. The majority of Frontiers in Pediatrics | www.frontiersin.org 2 April 2021 | Volume 9 | Article 646517 Vallasciani et al. Hydronephrosis Classification Preferences Worldwide Survey FIGURE 1 | Demographic details of the 380 participants to the study. FIGURE 2 | Graphic representation of the differences between Grading systems provided and Grading systems preferred. Frontiers in Pediatrics | www.frontiersin.org 3 April 2021 | Volume 9 | Article 646517 Vallasciani et al. Hydronephrosis Classification Preferences Worldwide Survey TABLE 1 | P-values corresponding to a G-test of independence between the variables Q5, Q7, Q8, …Q13 and the demographic variables Q1, …, Q4. Q1. What is your Q2. What is your Q3. Years of experience Q4. How many cases of subspecialty? geographical area? in Pediatric Urology hydronephrosis you manage in a typical week? Q5. When you deal with a case of 0.05201 0.00000007 0.3287 1.955e-06 hydronephrosis, which is your favorite classification system? Q7. Why do you prefer the system you 0.4818 0.07535 0.7218 0.2789 use? (you can choose more than one) Q8. What are the shortcomings of the 0.9644 0.3354 0.6167 0.6515 system you use? (you can choose more than one) Q9. Do you have direct communication 0.3372 0.001802 0.1221 0.1835 with your radiology report providers? Q10. If yes, how often? 0.4125 0.00004 0.938 0.257 Q11. Which is the most frequently used 0.9974 0.0000005 0.2386 0.0004758 classification system you see in your practice (the one most used by your providers)? (you can choose more than one) Q12. Did you attempt to build a common 0.1706 0.001403 0.008423 0.4134 language for description of hydronephrosis among your own team? Q13. Are you available to change your 0.586 0.1987 0.0403 0.6104 preference in case the majority of Pediatric Urologist prefers another grading system? We see that the responses to question Q5 depend on the demographic variables Q2 and Q4. Q9 is dependent on Q2. Q10 depends on Q2. The answers to Q11 depend on Q2 and Q4 while the answers to Q12 are associated with Q2 and Q3. Finally, the categories taken by Q13 depends on the categories taken by Q3. Bolded P values < 0.005. the participants described direct communication to varying package ade4 in R with data points labeled by continents is degrees (Supplementary Table 2). In Europe, North America available in the complementary documents of this manuscript). and Oceania this is more common than in the rest of the world. The participants were able to express their opinions regarding The frequency of this contact is also different with the higher the utility of each system by grading it from “very useful” to frequency in Europe and Oceana. The grading system used by “useless” (question 6). This was also an open question permitting providers also varied geographically (Supplementary Table 3). multiple responses. Scores were given according to the number In all the regions except North America the most utilized system of responses in each category except for “not known” which was by the providers is the Pelvic AP diameter. In North America, not scored. In order to assign a numeric value to this answer, each the SFU system is the most frequently used. In most areas, category had a weighted multiplying factor as shown in Table 2. there was an attempt to build a common system, but more The highest scores for utility were obtained by the Pelvic AP common in Europe, South America, and Oceania (Figure 3 and diameter and the SFU systems. The systems categorized as “not Supplementary Table 4). known” by most of the participants were the ESPR and the Onen Years of experience was associated with an increased attempt (112 and 127, respectively). to build a common system (Supplementary Table 5). The Participants were invited to express their opinion regarding willingness to change the preferred system (91%, range 88–98) the strengths of their preferred systems. Points of strength for revealed that those who most willing are the group with middle mild-moderate-severe, Pelvic AP diameter, and SFU systems was experience (10–15 years) (Supplementary Table 6). “Familiarity” and “Simplicity.” In addition, “Good prognostic The volume of cases also had an impact on the preferred value” was a strength reported for the SFU and UTD systems. grading system (Supplementary Table 7). SFU and UTD The most frequent shortcomings noted were principally that the preference grew with increasing patient volume. In contrast, system was “Not used universally.” the low volume responders preferred the Pelvic AP diameter system (Figure 3). The system used by providers DISCUSSION (Supplementary Table 8) was similar to the preferred grading system. Higher volumes correlated with preference for SFU and Prenatal and postnatal hydronephrosis is a very common UTD and lower volumes with the mild-moderate-severe system. condition affecting approximately 1% of pregnancies. In many The multivariate analysis revealed no statistically significant countries/areas the role of pre and postnatal counseling and care correlations between all the variables studied (two-dimensional for hydronephrosis is provided by Pediatric Urologist or by either correspondence analysis plot of the questionnaire data using the Pediatric Surgeons or Adult Urologists dedicated to pediatric Frontiers in Pediatrics | www.frontiersin.org 4 April 2021 | Volume 9 | Article 646517 Vallasciani et al. Hydronephrosis Classification Preferences Worldwide Survey FIGURE 3 | Difference of preferences based on geographical provenience (Top) and cases per week volume (Bottom). patients. The goal of a common and objective language in the Onen presented his individual experience with a modified description of the degree and characteristics of hydronephrosis system aimed to better stratify the ultrasound characteristics along with prognostic clinical correlation has been attempted of the hydronephrotic kidney and its clinical significance (3). since the wide use of ultrasound as first line investigation in Finally, a consensus among several societies of Pediatric Urology, both the prenatal and postnatal period. Dhillon et al. published Nephrology and Radiology was accomplished in 2014 and a detailed report correlating the degree of dilatation with the resulted in the Urinary Tract Dilatation system (4). This system clinical outcome in terms of need for surgical intervention (5). introduced additional characteristics of the urinary tract not Although many experienced physicians prefer to independently considered in the previous systems including ureteric dilation assess the radiological images rather than rely on reports, the and bladder abnormalities and can be considered an integration images are not always available adding delays in management of the SFU and anterior-posterior diameter systems. decision and timing of intervention. The evolution of classification systems has attempted to Grading systems have evolved in complexity over time improve prognostic ability by combining additional sonographic beginning with the simpler, classic “mild-moderate-severe” findings. The use of multiple different classification systems system (6) and the anterior-posterior diameter (7). In 1993 the makes communication and translation of research findings Society for Fetal Urology proposed the SFU classification system difficult. Over the last 30 years, multiple studies have been for postnatal hydronephrosis (1), followed by the European done evaluating the strengths and challenges of the various Society for Pediatric Radiology which proposed its modified classification systems. Considering multiple specialities, Zanetta system by adding the anterior-posterior diameter (2). In 2007, et al. (8) demonstrated lack of agreement within different Frontiers in Pediatrics | www.frontiersin.org 5 April 2021 | Volume 9 | Article 646517 Vallasciani et al. Hydronephrosis Classification Preferences Worldwide Survey TABLE 2 | Opinion of the responders of each system. Very useful (x4) Somewhat Minimally Useless (x1) SCORE Not known useful (x3) useful (x2) Mild-moderate-severe system 46 (184) 125 (375) 129 (258) 53 870 5 Pelvic AP Diameter measurements 184 (736) 137 (411) 31 (62) 4 1,213 2 Society of Fetal Urology system (1) 191 (764) 125 (375) 24 (48) 2 1,189 8 ESPR Pediatric Uroradiology Working 29 (116) 138 (276) 63 (126) 10 528 112 Group grading (2) Onen grading system (3) 22 (88) 120 (360) 64 (128) 17 593 127 Urinary Tract Dilation (UTD) classification 113 (452) 142 (426) 51 (102) 4 984 44 system (4) Bolded values of higher significance. specialities involved in the management of hydronephrosis most of the physicians charged with the management of pediatric both in grading system and management. Our study hydronephrosis prefer the SFU and APD systems because of uniquely evaluates opinions regarding the various pediatric familiarity and simplicity with these systems (37 and 34%, hydronephrosis classification systems from a large number of respectively). Respondents noted that their imaging providers surgical specialists from throughout the world. most often report findings utilizing the mild-moderate-severe Our study supports our hypothesis that that there is no system or the APD measurements (28 and 39%, respectively) single preferred hydronephrosis grading system among pediatric except for North America where the SFU system is more seen surgeons and urologists. The geographical differences were (50%). The greatest reported shortcoming of all the systems was subtle in some areas while particularly marked in others. This the lack of universal utilization. Nearly all respondents were may reflect agreement between regional societies or presence optimistic that if a consensus regarding a classification system of leadership opinions that influence preferences toward a was determined, they would be able to have this new system particular system. implemented at their institution. The observations taken from Our study is not without limitation. Although we had 380 this study may serve as basis for the construction of a common respondents, it is not known how representative this group is of worldwide system among physicians managing hydronephrosis the global census of physicians that manage fetal and pediatric and imaging providers. As APD and SFU are the preferred hydronephrosis. Currently there is no estimation of the number systems and the UTD a newer combination of both, it is possible of physicians (pediatric urologists, pediatric surgeons) practicing that with time, UTD may become the universal language for worldwide. Based on the organization with the highest number of reporting hydronephrosis. The result of this survey, however, physicians dedicated to Pediatric Urology, the European Society shows that this time has not come yet. for Pediatric Urology whose roster is of 790 members from different areas of the world (www.espu.org website) plus another DATA AVAILABILITY STATEMENT 450 certified by SPU and SFU, it can be hypothesized that the number of respondents to the present survey represents a The raw data supporting the conclusions of this article will be significant portion of the physicians managing cases of children made available by the authors, without undue reservation. with hydronephrosis. The utilization of multiple sources of engagement and repetition of the invitations was a strategy to AUTHOR CONTRIBUTIONS enhance inclusion and representation as recommended by Ponto in the paper on surveys as a research tool (9). SV, AB, JG, MM, CC, and P-JL: conception and design. SV, AB, The heterogeneity in “years of experience,” “subspeciality,” and JG, MM, CC, MF, HZ, and P-JL: acquisition of data. SV and ME: “geographic area” are also limitations of the study. The lack of an analysis and interpretation of data. SV, ME, JG, and CC: drafting overriding organization for physicians treating hydronephrosis of the manuscript. JG, CC, MF, and P-JL: critical revision of necessitated broad solicitation of voluntary participation by the manuscript for important intellectual content. ME: statistical physicians of differring backgrounds. Another limitation is that analysis. All authors contributed to the article and approved the the opinions were expressed anonymously [although 284/380 submitted version. (73%) participants voluntarily disclosed their identity] making it impossible to assess the validity of all responses. SUPPLEMENTARY MATERIAL The Supplementary Material for this article can be found CONCLUSION online at: https://www.frontiersin.org/articles/10.3389/fped. 2021.646517/full#supplementary-material The present survey demonstrates that there is no single preferred Supplementary Figure 1 | Two-dimensional correspondence analysis plot of the hydronephrosis grading system among pediatric surgeons and questionnaire data using the package ade4 in R. The data points are labeled by urologists. Despite a clear favorite, even with regional variations, continents. Frontiers in Pediatrics | www.frontiersin.org 6 April 2021 | Volume 9 | Article 646517 Vallasciani et al. Hydronephrosis Classification Preferences Worldwide Survey Supplementary Table 1 | Preferred system by geographical area. Supplementary Table 5 | Attempt to build a common system by years of experience. Supplementary Table 2 | Communication with providers by geographical area. Supplementary Table 6 | Availability to change the preferred system by years of experience. Supplementary Table 3 | System by providers by geographical area. Supplementary Table 7 | Preferred system by number of cases seen by week. Supplementary Table 4 | Attempt to build a common system by geographical Supplementary Table 8 | System by providers by number of cases seen by area. week. REFERENCES 7. Grignon A, Filion R, Filiatrault D, Robitaille P, Homsy Y, Boutin H, et al. Urinary tract dilatation in utero: classification and clinical applications. 1. Fernbach SK, Maizels M, Conway JJ. Ultrasound grading of hydronephrosis: Radiology. (1986) 160:645–7. introduction to the system used by the Society for Fetal Urology. Pediatr Radiol. 8. Zanetta VC, Rosman BM, Bromley B, Shipp TD, Chow JS, Campbell (1993) 23:478–80. JB, et al. Variations in management of mild prenatal hydronephrosis 2. 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