Society For Pediatric Urology

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How Can We Quantify Worsening Hydronephrosis On Ultrasound?
Amr Hodhod, M.D, Moahmed El-Sherbiny, M.D, Roman Jednak, M.D, John Paul Capolicchio, M.D.
McGill University Health Center, Montreal, QC, Canada.

Introduction and objectives: Worsening hydronephrosis (HN) is a frequent indication for pyeloplasty in children with conservatively managed hydronephrosis. Apart from upgrading, the worsening of HN can be described by an increase in anteroposterior renal pelvic diameter (APD) on ultrasound (US), consistent with the fact that APD is an important predictor for pyeloplasty. Currently, no objective criteria exist which would permit one to quantify if the degree of HN deterioration is significant. We sought to answer this question – what is a significant degree of worsening HN on US?
Patients and methods: We retrospectively reviewed patients' data who presented with antenatal hydronephrosis from 2004 to 2017. We selected a cohort of consecutive patients who had Pyeloplasty for worsening hydronephrosis with conservative management. A Control group consisted of patients with conservatively managed high-grade hydronephrosis (SFU grade 3 and 4) and initial APD diameter ≥10 mm. For the Pyeloplasty group, we reviewed the last two US before surgery in addition to the initial one. For the Control group, we reviewed the last two ultrasounds before the age of 3 years old or the last two ultrasounds before resolution, in addition to the initial one. Ultrasound images were reviewed to record the APD and SFU grade. The percentage worsening of the APD (PW-APD) was calculated by comparing APD at two time points; the First- Last US and the Previous-Last US.
Results: There were 37 patients (37 units) in the Pyeloplasty group and 47 patients (49 units) in the Control group. Patients in the Pyeloplasty group deteriorated at a median age of 13.3 months (4-148.1). There was no difference in the initial APD between the two groups (p=0.12). The median PW-APD in the First-Last US was 100% (14.3-525) for the Pyeloplasty group and -28.4% (-100 ˗ 33.3) for the Control group (p<0.001). Regarding the Previous-Last US, the median PW-APD was 58.8% (10.5- 297) for the Pyeloplasty group while for the Control group it was -4.7% (-100 ˗ 69.5) (p<0.001).
Conclusion: The PW-APD was significantly different between the Pyeloplasty and the Control group. One hundred percent worsening of the APD in the First-Last US and 59% APD worsening in the Previous-Last US was observed in renal units that underwent pyeloplasty for worsening hydronephrosis.

ParameterPyeloplasty Group
(37 patients)
Control Group
(47 patients)
P value
Median age at presentation (range)*0.4 (0.1-47.7)0.73 (0.03-6.3)0.97
Gender Male (%)27 (72.9)37 (78.7)0.49
Female (%)10 (27.1)10 (21.3)
Side Right (%)10 (27)9 (18.4)0.24
Left (%)27 (73)40 (81.6)
LateralityUnilateral (%)37 (100)45 (95.7)0.2
Bilateral (%)0 (0)2 (4.3)
Initial SFUGrade 2 (%)3 (8.1)0 (0)0.001
Grade 3 (%)18 (48.7)41 (85.7)
Grade 4 (%)16 (43.2)8 (14.3)
Median Follow up period (range)*13.3 (4-148.1)18.7 (10.9-32.4)0.02

*Age is presented in months
Table 1 The demographics of included patients
ParameterPyeloplasty GroupControl GroupP value
Initial SFUGrade 2 (%)3 (8.1)0 (0)<0.001
Grade 3 (%)18 (48.6)41 (85.7)
Grade 4 (%)16 (43.2)8 (14.3)
Median APD1 (range)14 (4-27)12.8 (10-22)0.12
Previous last SFUGrade1 (%)0 (0)1 (2)0.004
Grade2 (%)1 (4.3)17 (34.7)
Grade 3 (%)12 (52.2)25 (51)
Grade 4 (%)10 (43.5)6 (12.3)
Median APD2 (range)17 (9-30)9 (4-18.7)<0.001
Last SFUGrade0 (%)0 (0)3 (6.1)<0.001
Grade1 (%)0 (0)4 (8.2)
Grade2 (%)0 (0)19 (38.8)
Grade 3 (%)3 (8.1)21 (44.9)
Grade 4 (%)34 (91.9)2 (4)
Median APD3 (range)28 (17-54)9.8 (0-18)<0.001

Table Ultrasound findings in both groups including the SFU grading and APD measurement.
ParameterPyeloplasty GroupControl GroupP value
First-Last ultrasounds
Number of renal units3749
Median time interval (range)*9.1 (3-101.5)16.8 (9.7-31.9)<0.001
% of APD Worsening
Median (range)
100 (14.3-525)-28.4 (-100 - 33.3)<0.001
Previous-Last ultrasounds
Number of renal units2349
Median time interval (range )*5.6 (1.6-63.9)7 (3.8-17.9)<0.001
% of APD Worsening
Median (range)
58.8 (10.5-297)-4.7 (-100-69.5)<0.001

* Time is presented in months
Table Percentage of APD worsening regarding the treatment modality


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