History Of Prenatal Hydronephrosis Research Articles

Correlation between renal sonographic measurements and differential renal function obtained from nuclear renography in children with unilateral hydronephrosis

Children with higher grades of hydronephrosis often undergo mercaptoacetyltriglycine nuclear renography scans (MAG3) to assess differential renal function (DRF) and drainage. Although MAG3 helps identify the potential need for pyeloplasty, its use incurs increased costs, radiation exposure, and stress for children and families. Several studies demonstrate pyramidal thickness (PT)≤3mm as a reliable predictive risk factor for pyeloplasty in children with a history of prenatal hydronephrosis. Our hypothesis was that renal sonographic measurements including PT and parenchymal thickness (ParT) correlate with DRF in children with high-grade unilateral hydronephrosis and may be used to better select the need and frequency of MAG3 scans in children at increased risk for diminished relative renal function. The objective of this project was to determine the correlation between sonographic renal measurements and DRF in patients with unilateral hydronephrosis, we assessed: 1) the correlation between PT, ParT, and the ratio of PT/ParT in hydronephrotic kidneys to DRF, 2) the correlation between the ratio of hydronephrotic PT/contralateral non-hydronephrotic PT and DRF, 3) the correlation between the ratio of hydronephrotic ParT/contralateral non-hydronephrotic ParT and DRF, and 4) the correlation between the ratio of (hydronephrotic PT/ParT)/(contralateral non-hydronephrotic PT/ParT) and DRF. We retrospectively reviewed 71 children with grades 3 or 4 unilateral hydronephrosis. Most patients presented with a history of prenatally detected hydronephrosis at median age (IQR) of 112 days (43-274). Measurements of PT and ParT were completed on 98 renal ultrasounds and DRF was collected from corresponding MAG3 scans. Threshold values were identified visually through scatterplots. Spearman's correlation coefficient and Fisher's p-values were calculated. Ratios of PT and ParT in hydronephrotic kidneys to contralateral non-hydronephrotic kidneys were positively correlated with DRF. Ratios of hydronephrotic PT/non-hydronephrotic PT>0.8 and hydronephrotic ParT/non-hydronephrotic ParT >0.7 occurred more frequently in patients with a DRF >40% (p=0.11 and p=0.001, respectively). A PT>3mm and ParT >5mm occurred significantly more frequently in patients with a DRF >40% (p=0.008 and p=0.006, respectively). Renal sonographic measurements including threshold values of PT>3mm, ParT > 5mm, ratio of hydronephrotic PT/contralateral non-hydronephrotic PT (>0.8), and ratio of hydronephrotic ParT/contralateral non-hydronephrotic ParT (>0.7) are good predictors of DRF >40% in unilateral high-grade hydronephrosis. These identified threshold values have potential utility in determining the need for nuclear renal scans in children with high-grade hydronephrosis.

Multicenter comparative study of open, laparoscopic, and robotic pyeloplasty in the pediatric population for the treatment of ureteropelvic junction obstruction (UPJO).

Dismembered open pyeloplasty described by Anderson and Hynes is the "gold standard" for the treatment of ureteropelvic junction obstruction. The aim of our study was to compare the results of open (OP) vs laparoscopic (LP) vs robotic (RALP) pyeloplasty. A multicenter prospective review was conducted of pyeloplasty surgeries performed at five high-volume centers between 2014 and 2018. Demographic data, history of prenatal hydronephrosis, access type, MAG3 renogram and differential renal function, surgery time, length of hospital stay, and complication rate (Clavien-Dindo) were recorded. Access type was compared using the Kruskal-Wallis, Chi-square, or Fisher's exact tests. A total of 322 patients were included: 62 OP, 86 LP, and 174 RALP. The mean age was 8.13 (r: 1-16) years, with a statistically significant lower age (mean 5 years) in OP (p < 0.001). There were no significant differences in the distribution of the side affected. Operative time was 110.5 min for OP, 140 min for LP, and 179 min for RALP (p < 0.0001). Hospital stay was significantly shorter in the RALP group than in the other groups (p < 0.0001). There were no differences in postoperative complications and reoperations between the three groups. Minimally invasive surgery for the management of UPJO in children is gaining more acceptance, even in patients younger than 1-year-old. Operative time continues to be significantly shorter in OP than in LP and RALP. Hospital stay was shorter in RALP compared to the other techniques. No differences were found in complication rates, type of complications, and reoperation rate.

Pediatric robotic-assisted laparoscopic pyeloplasty: Does age matter?

Although shown to be safe in infancy, robotic-assisted laparoscopic pyeloplasty (RALP) for ureteropelvic junction obstruction (UPJO) is most commonly performed in older children and adolescents. This study examined a contemporary RALP experience at a single tertiary pediatric center and compared outcomes in infants aged ≤1 year with an older cohort. All RALP procedures were entered into an Institutional Review Board-approved data registry from 2012 to 2016. Patients were retrospectively grouped according to age. The primary outcome was success rate. Secondary outcomes included complications and length of hospital stay. Failure was defined as the need for secondary surgical intervention for UPJO or worsening urinary tract dilation on imaging. Statistical analysis was performed using SPSS version 20. Mann-Whitney U testing was used for comparison. A total of 138 patients underwent RALP during 2012-2016, with a median age of 6 years (IQR 1, 13.25) and a male:female ratio of approximately 2:1. Of these, 34 (24.6%) were aged ≤1 year. Of all patients, 60 (43.5%) presented with a history of prenatal hydronephrosis, and 32% had a crossing vessel causing obstruction. An indwelling stent was placed in antegrade fashion in 71% of cases, and 18% had a percutaneously placed externalized stent. There were six (4%) failures requiring reoperation. Multivariate and comparative analysis demonstrated that the infant cohort utilized less morphine equivalents and more often had a percutaneous stent placed compared to the older cohort. Of the complications that occurred, 60% were minor (Clavien grades 1 and 2) and 40% were Clavien grade 3 in the infant cohort, and 70.1% and 29.9% in the older cohort, respectively. No studied criteria predicted failure in either cohort. This study presented one of the largest contemporary series of consecutive pediatric RALPs, and showed an overall success rate of 96%. There were no significant differences in length of hospital stay, and complications or failure rates in infants compared to older children. This study substantiated the ongoing trend towards the adaptation of robotic-assisted surgery for the entire pediatric patient population.

Robot-assisted laparoscopic lower pole partial nephrectomy in the pediatric patient

In pediatric urology, partial nephrectomy is used primarily to remove a non-functioning renal moiety in a duplicated system. There are few data on infants undergoing this procedure. As such, we present a robot-assisted laparoscopic lower pole partial nephrectomy in an infant. Our patient was an 11-month-old (10.7kg) male with a history of prenatal hydronephrosis, who was diagnosed postnatally with a duplicated right collecting system and severe hydroureteronephrosis of the right lower collecting system. A DMSA scan demonstrated no radiotracer uptake in the right lower pole. A robot-assisted laparoscopic lower pole partial nephrectomy was performed. A lower pole partial nephrectomy was accomplished. At 1 month postoperatively, an ultrasound demonstrated no hydronephrosis or perinephric fluid collection. Robotic partial nephrectomy is safe and feasible in pediatrics including both older children and infants. It is successful for both upper and lower pole partial nephrectomies.

Long-term results with the laparoscopic transposition of renal lower pole crossing vessels

For the treatment of ureterovascular pelviureteric junction obstruction (PUJO), transposition of lower pole crossing vessels (LPCV) has been described as an alternative to dismembered pyeloplasty. To report on the long-term follow-up of children after laparoscopic transposition of LPCV. A retrospective analysis of 70 children consecutively treated by laparoscopic transposition of LPCV. Candidate patients were selected on the basis of clinical history, renal ultrasound (US), and pre-operative mercaptoacetyltriglycine (MAG-3) scan. Selection criteria included: presence of LPCV with SFU Grade 1-2 hydronephrosis, impaired drainage on MAG-3 and intraoperative normal pelviureteric junction (PUJ) and ureter peristalsis. Thinned parenchyma, impaired renal function, or history of prenatal hydronephrosis were not considered as exclusion criteria. Children were clinically followed up with US and MAG-3 scan. Success was defined by symptom resolution with improvement in hydronephrosis. Seventy children, aged 8.3 years (range 2.75-16.0), were selected. Procedures were performed through transperitoneal laparoscopy (n = 42) or were robotic-assisted (n = 28). Operative time was 120 min and length of hospital stay was 2 days. The outcome was successful in 67/70 patients (96%), with a median follow-up of 52 months (range 13-114). There were three failures in children who eventually underwent dismembered pyeloplasty for a symptomatic, undiagnosed, intrinsic PUJ obstruction. Two of them had been postnatally followed for a resolving prenatally diagnosed hydronephrosis. Three children became free of symptoms, had improved hydronephrosis, but still showed impaired drainage on MAG-3 and are being closely followed up. Although this procedure proves to have long-term efficiency in selected indications, the main challenge is to intraoperatively ascertain the absence of associated intrinsic stenosis. Objective criteria remain difficult to establish, but intraoperative findings, including dependent, funnel-shaped, normal-looking PUJ with decreasing hydronephrosis after pelvis and LPCV mobilisation, and efficient peristalsis across the PUJ under intraoperative diuretic test, represent a low likelihood of associated intrinsic stenosis. Ipsilateral impaired renal function doesn't seem to be associated with an adverse outcome. In contrast, a prenatal history of mild or self-resolving hydronephrosis in a patient later presenting with intermittent dilatation, raises the suspicion of associated intrinsic PUJ obstruction, as it is associated with a higher risk of failure. With a long postoperative follow-up, the robotic-assisted or laparoscopic vascular hitch procedure has been successful in treating a selected group of children with obstructive LPCV, and represents a safe and reliable alternative to standard dismembered pyeloplasty in the absence of intrinsic PUJO suspected on prenatal US.

MP44-08 IMAGING AFTER UTI IN OLDER CHILDREN AND ADOLESCENTS

You have accessJournal of UrologyPediatrics: Urinary Tract Infection & Vesicoureteral Relux1 Apr 2014MP44-08 IMAGING AFTER UTI IN OLDER CHILDREN AND ADOLESCENTS Michael P. Kurtz, Jeanne S. Chow, Emilie K. Johnson, William Tan, Tanya Logvinenko, and Caleb P. Nelson Michael P. KurtzMichael P. Kurtz More articles by this author , Jeanne S. ChowJeanne S. Chow More articles by this author , Emilie K. JohnsonEmilie K. Johnson More articles by this author , William TanWilliam Tan More articles by this author , Tanya LogvinenkoTanya Logvinenko More articles by this author , and Caleb P. NelsonCaleb P. Nelson More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.1383AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail Introduction and Objectives While the 2011 AAP guidelines for evaluation after urinary tract infection (UTI) focused on infants age 2-24 months, there are few guidelines or data regarding workup in older children. Both voiding cystourethrogram (VCUG) and renal and bladder ultrasound (RBUS) have been used in such patients, but the value of such tests is uncertain. We sought to determine the clinical yield of RBUS and VCUG among older children and adolescents after UTI. Methods We analyzed VCUG and RBUS findings and clinical history of 3995 patients who underwent both studies on the same date between 1/06-12/10, and selected patients age 5-18 years who underwent imaging for indication of UTI. Patients with prior postnatal GU imaging or history of prenatal hydronephrosis (PNH) were excluded. RBUS was defined as positive for any degree of hydronephrosis or hydroureter, renal parenchymal or bladder abnormalities. A positive VCUG was defined as VUR>GII and/or bladder or urethral anomalies (e.g. diverticulum). Results We identified a cohort of 141 patients, 77% were of age 5-8 years, 29% age 8-12, and 2.8% age 12-18. 76.6% were female. 78.7% patients had a history of febrile UTI; 53.9% had a history of recurrent UTI. RBUS findings among girls included 9.2% hydronephrosis, 2.8% with ureteral dilation, 13% with renal parenchymal findings, and 9.2% with bladder findings. Among boys, 6.1% had hydronephrosis, 9.1% had ureteral dilation, 12% had renal parenchymal findings, and 18% had bladder findings. No subjects had moderate or greater hydronephrosis. On VCUG, VUR was observed in 49/141 subjects (34%); 41/108 (38%) girls and 8/33 (24%) boys. Other bladder or urethral anomalies were seen in 12%. 6.4% of all subjects had grade I, 26.2% had grade II-III, and1.4% had grade >III VUR. One boy had concurrent upper tract obstruction (precluding VUR grading); no boys had VUR > grade II. One boy had a urethral anomaly. Among girls, 1.9% had VUR > grade III. The test characteristics (with 95% CI) of any RBUS abnormality for VUR > grade II (or bladder or urethral anomalies) were: sensitivity 0.53 (0.36-0.70), specificity 0.71 (0.62-0.79), PPV 0.33 (0.22-0.48), NPV 0.85 (0.76-0.91). For any VUR grade (or bladder or urethral anomalies), these were: sensitivity 0.49 (0.37-0.62), specificity 0.76 (0.66-0.84), PPV 0.58 (0.44-0.71), NPV 0.69 (0.59-0.77). Conclusions Among older children with a history of UTI, mild genitourinary anomalies are common, but the yield of diagnostic imaging high grade hydronephrosis or high-grade VUR is very low. Renal ultrasound is not reliable as a screening test for predicting VCUG findings such as VUR, regardless of grade. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e445-e446 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Michael P. Kurtz More articles by this author Jeanne S. Chow More articles by this author Emilie K. Johnson More articles by this author William Tan More articles by this author Tanya Logvinenko More articles by this author Caleb P. Nelson More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Ultrasound as a Screening Test for Genitourinary Anomalies in Children With UTI

The 2011 American Academy of Pediatrics guidelines state that renal and bladder ultrasound (RBUS) should be performed after initial febrile urinary tract infection (UTI) in a young child, with voiding cystourethrogram (VCUG) performed only if RBUS shows abnormalities. We sought to determine test characteristics and predictive values of RBUS for VCUG findings in this setting. We analyzed 3995 clinical encounters from January 1, 2006 to December 31, 2010 during which VCUG and RBUS were performed for history of UTI. Patients who had previous postnatal genitourinary imaging or history of prenatal hydronephrosis were excluded. Sensitivity, specificity, and predictive values of RBUS for VCUG abnormalities were determined. We identified 2259 patients age <60 months who had UTI as the indication for imaging. RBUS was reported as "normal" in 75%. On VCUG, any vesicoureteral reflux (VUR) was identified in 41.7%, VUR grade >II in 20.9%, and VUR grade >III in 2.8%. Sensitivity of RBUS for any abnormal findings on VCUG ranged from 5% (specificity: 97%) to 28% (specificity: 77%). Sensitivity for VUR grade >III ranged from 18% (specificity: 97%) to 55% (specificity: 77%). Among the 1203 children aged 2 to 24 months imaged after a first febrile UTI, positive predictive value of RBUS was 37% to 47% for VUR grade >II (13% to 24% for VUR grade >III); negative predictive value was 72% to 74% for VUR grade >II (95% to 96% for VUR grade >III). RBUS is a poor screening test for genitourinary abnormalities. RBUS and VCUG should be considered complementary as they provide important, but different, information.

The role of urinary TIMP1 and MMP9 levels in predicting vesicoureteral reflux in neonates with antenatal hydronephrosis

Antenatal hydronephrosis (AH) is commonly found on evaluation of pregnant women and 20-30 % of neonates have vesicoureteral reflux (VUR). In order to diagnose VUR, we required invasive testing and exposure of the neonate to radiation. The concentrations of a matrix metalloproteinase, MMP9, and its inhibitor TIMP1, were analyzed in hydronephrotic newborns with VUR and were compared to those without reflux. The neonates with a history of prenatal hydronephrosis were enrolled in two groups based on imaging study results, the neonates with VUR and without VUR. Neonates with a normal prenatal history and postnatal ultrasound were placed in a third group. We measured the random urinary levels of MMP9, TIMP1, and creatinine, their cut-off values and the MMP9/Cr and MMP9/TIMP1/Cr ratio was calculated, and an ROC curve was drawn. Sixty-nine neonates were enrolled in three groups; 27 patients (20 male, seven female) with AH and VUR were in group 1, 23 neonates (19 male, four female) without VUR were placed in group 2, and 19 (15 male, four female) acted as controls in group 3. The differences between the three groups and the normal and total hydronephrotic groups were statistically significant for MMP9, the MMP9/Cr, MMP9/TIMP1, and MMP9/TIMP1/Cr ratios. The urinary TIMP1 and TIMP1/Cr ratios were not significantly different between the groups. A cut-off value of MMP9 was measured as 358.5 ng/ml (sensitivity [sens] 74 %, specificity [spec] 78 %) and was used to compare groups 1 and 2. For groups 2 and 3, this cut-off was 181.00 pg/ml (sens 91 %, spec 89 %). The cut-off values measured for the MMP9/TIMP1 ratio were 30.32 (sens 70 %, spec 61 %) and 9.85 (sens 96 %, spec 89 %) to compare groups 1 and 2, and 2 and 3, respectively. We found no valuable cut-offs for the TIMP1 and TIMP1/Cr values. There was no difference between neonates with mild, moderate, and severe VUR according to urinary biomarker concentrations. Evaluation of urinary levels of MMP9, or the MMP9/Cr, MMP9/TIMP1, or MMP9/TIMP1/Cr ratios may help us to differentiate the newborns with hydronephrosis and VUR from those without reflux.

Vesicoureteral Reflux and Urinary Tract Infection in Children With a History of Prenatal Hydronephrosis—Should Voiding Cystourethrography be Performed in Cases of Postnatally Persistent Grade II Hydronephrosis?

Vesicoureteral Reflux and Urinary Tract Infection in Children With a History of Prenatal Hydronephrosis—Should Voiding Cystourethrography be Performed in Cases of Postnatally Persistent Grade II Hydronephrosis?

Vesicoureteral Reflux and Urinary Tract Infection in Children With a History of Prenatal Hydronephrosis—Should Voiding Cystourethrography be Performed in Cases of Postnatally Persistent Grade II Hydronephrosis?

The clinical relevance of prenatal hydronephrosis is not well-defined. We determined the risk of febrile urinary tract infection in the absence of screening for vesicoureteral reflux, and whether postnatal voiding cystourethrography should be performed in patients with a history of prenatal hydronephrosis and postnatally persistent Society for Fetal Urology grade II hydronephrosis. From a longitudinal database of patients with prenatal hydronephrosis maintained since 1998 we identified those with postnatally persistent grade II hydronephrosis. This cohort was divided into patients who were and were not screened with an initial voiding cystourethrogram. The rates of vesicoureteral reflux and development of febrile urinary tract infection were determined. Of 2,076 patients with prenatal hydronephrosis 1,514 had grade II hydronephrosis. Of the patients 76% underwent an initial voiding cystourethrogram and vesicoureteral reflux was found in 28%. There was no relation between laterality of hydronephrosis and incidence of vesicoureteral reflux. There was no difference between nonscreened and screened patients with respect to gender and laterality of hydronephrosis. Urinary tract infection developed in 1.3% of the patients who were screened and did not have vesicoureteral reflux and, therefore, were not receiving antibiotics. Of the screened patients with vesicoureteral reflux who were receiving prophylactic antibiotics urinary tract infection developed in 1.6% at a mean age of 9.4 months. In 363 patients who did not undergo an initial voiding cystourethrogram we estimated (based on the screened population) that 101 would have vesicoureteral reflux and 5 would have a urinary tract infection. However, a febrile urinary tract infection developed in 16 patients (4.4% overall, p <0.0001) at a mean age of 9.3 months. Voiding cystourethrogram performed in these 16 patients revealed vesicoureteral reflux in 12. Of all the patients with a urinary tract infection who were ultimately observed to have vesicoureteral reflux (including those initially screened and those discovered to have reflux after a urinary tract infection) the laterality of hydronephrosis, grade of reflux and laterality of reflux were comparable. In patients with a history of prenatal hydronephrosis who are observed to have postnatally persistent grade II hydronephrosis identification of vesicoureteral reflux and use of prophylactic antibiotics significantly reduce the risk of febrile urinary tract infection. Therefore, we recommend that patients with a history of prenatal hydronephrosis and postnatally persistent hydronephrosis be screened with voiding cystourethrography early in life, and be placed on prophylactic antibiotics until the screening results are known.

Prenatal hydronephrosis: early evaluation

Fetal hydronephrosis is the most common anomaly detected on antenatal ultrasound examination, and its significance and management remain controversial. This review aims to address the early postnatal evaluation of the child with prenatally diagnosed hydronephrosis. The risk of significant urological pathology increases with the severity of prenatal hydronephrosis. The most common underlying conditions are ureteropelvic junction obstruction and vesicoureteral reflux. The use of postnatal ultrasonograpy in all patients with a history of any degree of prenatal hydronephrosis is routine, but ascertaining which patients require postnatal evaluation with a voiding cystourethrogram to investigate for vesicoureteral reflux remains controversial. Mild cases are the most controversial as the risk of pathology is lessened, however the risk of vesicoureteral reflux and consequent febrile urinary tract infection may be significant. Early postnatal evaluation of all children with a history of prenatal hydronephrosis with a voiding cystourethrogram may reduce this risk. No prospective randomized clinical trials are available, however, to adequately address the question of which patients require postnatal evaluation. The postnatal management of prenatal hydronephrosis remains controversial. Sufficient data are lacking to inform patient risk stratification. Therefore, early postnatal evaluation of children with a history of any degree of prenatal hydronephrosis with an ultrasound and voiding cystourethrogram is reasonable and may reduce the risk of febrile urinary tract infection.

Predictive Factors of Early Spontaneous Resolution in Children With Primary Vesicoureteral Reflux

Questions regarding the efficacy and safety of long-term prophylactic antibiotics and the option of minimally invasive therapy have increased clinical emphasis on predicting early resolution in patients with vesicoureteral reflux. We reviewed multiple potential prognostic factors in addition to grade to enhance predictive ability regarding early vesicoureteral reflux resolution. Medical records and cystograms from 324 children (257 girls and 67 boys) with primary vesicoureteral reflux were reviewed. Multiple factors were analyzed with respect to outcome and multivariable dependent tables were constructed to enhance the prediction of vesicoureteral reflux resolution. Mean +/- SD age at diagnosis was 2.3 +/- 2.1 years and followup was 1.7 +/- 2.8 years. Reflux grade was significantly associated with resolution (p <0.001). Multivariate analysis stratifying by grade demonstrated that a bladder volume at reflux onset on the initial cystogram of greater than 50% of predicted bladder capacity (p <0.001), age younger than 2 years at diagnosis (p = 0.003) and history of prenatal hydronephrosis (p <0.001) were significant factors predicting resolution within 2 years. Multivariable tables using age, bladder volume at reflux onset and grade demonstrated that children younger than 2 years at diagnosis and volume at onset greater than 50% of predicted bladder capacity had a higher early resolution rate for grades 2 (p = 0.012) and 3 (p <0.001) reflux. Initial reflux grade, bladder volume at reflux onset, age at diagnosis and history of prenatal hydronephrosis were shown to be independent factors affecting the resolution rates of vesicoureteral reflux. The multivariable tables permit improved individualized prediction of resolution in patients with grades 2 and 3 reflux.

DOES EVERY PATIENT WITH PRENATAL HYDRONEPHROSIS NEED VOIDING CYSTOURETHROGRAPHY?

Purpose Prenatal ultrasound has allowed early identification of urinary tract abnormalities that may require urological followup or early intervention. While all children with prenatal hydronephrosis should undergo ultrasound within the first few weeks of life, we believe that there is a subset of postnatal hydronephrosis for which voiding cystourethrography can be avoided if careful observation is continued. Materials and Methods For 5 years 175 infants with a history of prenatal hydronephrosis were evaluated by ultrasound. Of 60 infants with less than Society for Fetal Urology grade II unilateral or bilateral hydronephrosis 44 underwent voiding cystourethrography as part of the early evaluation and 16 were observed without voiding cystourethrography. Four infants for whom we would routinely obtain voiding cystourethrography were excluded from study due to severe prenatal hydronephrosis, renal duplication, hydroureter, ipsilateral small or echogenic kidney and grade II or higher hydronephrosis. Results Voiding cystourethrography was positive in 6 of the 40 infants (15%) with less than grade II hydronephrosis. Of these cases 3 had grade III or higher vesicoureteral reflux and 1 with high grade reflux required reimplantation. None of the 16 patients followed without voiding cystourethrography has required further evaluation or intervention. In all patients with negative or no voiding cystourethrography parenchyma was preserved and hydronephrosis stabilized or resolved. Conclusions Prenatal and postnatal ultrasound in infants should be used to guide further urological evaluation. Among infants with less than grade II hydronephrosis postnatally 15% had reflux on voiding cystourethrography, which is significantly higher than that reported among normal children (approximately 1%). However, none of the 16 infants observed without voiding cystourethrography on short-term antibiotic prophylaxis had deleterious renal events with 6 months to 4.5 years of followup. Therefore, we question the actual significance of the reflux detected in the first cohort of infants. Voiding cystourethrography can provide a definitive answer. However, we also believe that it is not absolutely mandatory based on the outcome in the observed group. With careful counseling and followup most patients with less than grade II hydronephrosis can be observed without urological sequela.