The Society for Fetal Urology consensus statement on the evaluation and management of antenatal hydronephrosis

Hydronephrosis severity score: an objective assessment of hydronephrosis severity in children-a preliminary report

The main challenge in the management of antenatally diagnosed hydronephrosis and ureteropelvic junction obstruction (UPJO) is to differentiate the one that is likely to resolve from the pathological one. In this study, a new hydronephrosis severity score (HSS), combining ultrasonographic and renographic parameters, has been developed. Hydronephrosis severity score was analyzed with regard to its usefulness in assessing the severity of UPJO, postoperative resolution, and interobserver reliability.

METHODS

Hydronephrosis severity score was devised with three parameters: differential renal function (DRF), drainage curve pattern, and ultrasonogram grade (Table 1). Hydronephrosis severity score ranges were divided as 0-4, mild; 5-8, moderate; and 9-12, severe and compared with clinical outcomes (resolution, persistence, or surgical intervention) by retrospective case record review of children with unilateral UPJO. Among those who underwent surgery, surgical outcomes were compared with changes in HSS at 6-month follow-up. Hydronephrosis severity score was computed by three observers, and interobserver variability was calculated.

RESULTS

A total of 125 case records (male:female = 93:32; right:left = 44:81) were analyzed. Among the patients analyzed, none (0/59) with HSS 0-4 warranted surgery, whereas 1 of 35 patients with HSS 5-8 underwent surgery, and all (31/31) with HSS 9-12 underwent surgery (P = 0.001). Overall, hydronephrosis resolved in 65, persisted in 28, and required surgery in 32 patients. Mean (standard deviation) HSS was 2.1 (0.75) in whom it resolved, 6.2 (0.78) in whom it persisted, and 10.2 (0.79) in those who underwent surgery (analysis of variance P = 0.001). Among those who underwent surgery, a better recovery of HSS was noted in younger infants (aged 2-5 months) with higher pre-operative DRF. There was 94.4% median agreement between radiologists and the surgeon (kappa 0.851), indicating a very good interobserver agreement.

DISCUSSION

Loss of DRF on progressive renograms remains the accepted criterion of significant UPJO although the lost function does not always recover after pyeloplasty. Newer scoring systems keep evolving to predict the need for surgery as well as assess resolution of UPJO, and the study's preliminary report suggests that HSS could turn out to be one such useful tool. In this study, those who deteriorated were the ones with HSS ≥9. One can use this as a criterion and decide on intervention before DRF deterioration. Hydronephrosis severity score could also be applied as an objective parameter for quantifying improvement/deterioration after surgery and comparing outcomes across centers. The drawbacks of the present study are its small size and the retrospective nature. Further prospective studies are required to validate the usefulness of HSS.

Urology Mythbusters: should hydronephrosis grade be used to decide which newborns should undergo voiding cystourethrogram?

In this episode of Mythbusters the premise that among infants with prenatally identified urinary tract dilation (UTD), voiding cystourethrogram (VCUG) should be performed in those with higher grade UTD but not in those with lower grade UTD is critically examined. It is concluded that severity of dilation is not strongly associated with risk of vesicoureteral reflux or other anomalies diagnosed by VCUG. Therefore, using hydronephrosis grade to decide which infants with UTD should undergo VCUG is not evidence based.

Is Laparoscopic Pyeloplasty for Ureteropelvic Junction Obstruction in Infants Under 1 Year of Age a Good Option?

Purpose: Laparoscopic pyeloplasty in children younger than 1 year of age is still debatable due to its supposed technical difficulties and failure rate. We present our experience and outcome in infants. Materials and Methods: A retrospective study was conducted in 3 Departments of Pediatric Surgery. We reviewed the records of the children under 1 year of age operated on for ureteropelvic junction obstruction (UPJO), between 2007 and 2017. Anderson-Hynes laparoscopic transabdominal dismembered pyeloplasty was performed. Patients' demographics, results of preoperative and postoperative exams, perioperative details, complications, hospital stay, and long-term follow-up results were analyzed. Results: Sixty cases were operated on during this period (49 boys, 11 girls). Mean age at operation was 4.5 months (1-12 months). Mean operating time was 140 min (80-240 min). There was no conversion in this group. There were four early complications: 1 ileus, 1 hypertension immediately post-operatively requiring medical treatment, 1 omental herniation through a drain orifice, and 1 percutaneous transanastomotic stent migrated intra-abdominally. The two last children had to be reoperated. Mean hospital stay was of 2 days (1-10 days). Late complications: two patients (3.4%) presented a recurrence of UPJO, one had been re-operated 15 months later and for the patient with persistent hypertension, nephropexy was performed for malrotated kidney, 1 year after pyeloplasty. Long term follow-up with a mean of 2.8 years (1-10 years) showed that surgery improved mean pelvic dilatation from 31.8 mm (13-63 mm) preoperatively to 15.3 mm (4-40 mm) postoperatively (P < 0.0001). The renal function slightly improved, from a mean of 35.7% (5-55%) it passed to 40.5% (0-54%), p = 0.137. In three cases the operated kidney became finally non-functional and atrophic. Conclusions: Laparoscopic transperitoneal pyeloplasty is feasible and safe in children younger than 1 year of age. Nevertheless, it requires experience and good intra-abdominal suturing skills. Laparoscopic pyeloplasty has a success rate comparable with open treatment but with less morbidity and better cosmetic results.

A Predictive Model of Postnatal Surgical Intervention in Children With Prenatally Detected Congenital Anomalies of the Kidney and Urinary Tract

The aim of this study was to identify predictive factors and develop a model to assess individualized risk of postnatal surgical intervention in patients with antenatal hydronephrosis. This is a retrospective cohort study of 694 infants with prenatally detected congenital anomalies of kidney and urinary tract with a median follow-up time of 37 months. The main event of interest was postnatal surgical intervention. A predictive model was developed using Cox model with internal validation by bootstrap technique. Of 694 patients, 164 (24%) infants underwent surgical intervention in a median age of 7.8 months. Predictors of the surgical intervention in the model were: baseline glomerular filtration rate, associated hydronephrosis, presence of renal damage and the severity of renal pelvic dilatation. The optimism corrected c statistic for the model was 0.84 (95%CI, 0.82-0.87). The predictive model may contribute to identify infants at high risk for surgical intervention. Further studies are necessary to validate the model in patients from other settings.

Pediatric voiding cystourethrography: An essential examination for urologists but a terrible experience for children

Voiding cystourethrography is the most important fluoroscopic examination in pediatric urology for the investigation of lower urogenital tract diseases, such as vesicoureteral reflux or urethral stricture. However, this invasive procedure imposes a significant burden on children and their parents, and recently there has been a paradigm shift in the diagnosis and treatment of vesicoureteral reflux. In the 2011 revision, the American Academy of Pediatrics guidelines on urinary tract infection recommended abandoning routine voiding cystourethrography after the first febrile urinary tract infection. In 2014, the randomized intervention for children with vesicoureteral reflux study recommended discontinuation of routine continuous antibiotic prophylaxis for vesicoureteral reflux. The time is now ripe to radically reconsider indications for voiding cystourethrography and the procedure itself.

The association between continuous antibiotic prophylaxis and UTI from birth until initial postnatal imaging evaluation among newborns with antenatal hydronephrosis

INTRODUCTION

There is a lack of consensus regarding the use of continuous antibiotic prophylaxis (CAP) during the interval between birth and initial postnatal imaging in infants with a history of antenatal urinary tract dilation (AUTD).

OBJECTIVE

To determine the incidence of urinary tract infection (UTI), and the association between CAP use and UTI during the interval between birth and the first postnatal renal ultrasound (RUS) in infants with AUTD.

STUDY DESIGN

A single-institution, retrospective cohort study of newborns with a history of AUTD. Infants undergoing RUS within 3 months of birth for an indication of 'hydronephrosis' between 2012 and 2014 were identified. A random sample of 500 infants was selected; six were excluded for concomitant congenital anomalies. Baseline patient (sex, race, insurance) and clinical characteristics (circumcision status, UTD risk score, receipt of CAP, UTI prior to RUS, age at UTI, and age at RUS) were collected via retrospective chart review. Descriptive statistics were calculated. To adjust for receipt of CAP, propensity score adjusted univariate logistic regression for UTI based on CAP status was performed.

RESULTS

Among the 494 infants with AUTD, 157 (32%) received CAP. Infants with normal/low-risk UTD scores were less likely to receive CAP than those with medium/high-risk UTD (23% vs 77%; P < 0.001). There was no difference in CAP based on sex, insurance, or circumcision status (among 260/365 males with known circumcision status). Overall, seven infants (1.4%) developed UTI prior to imaging: six (1.8%) without CAP vs one (0.64%) with CAP (P = 0.44). The median age at UTI was 59 days (range 2-84); among those with UTI, initial imaging occurred significantly later (66 vs 28 days; P = 0.001). The propensity score adjusted odds of developing UTI with CAP (vs without) was 0.93 (95% CI 0.10-8.32; P = 0.95). The Summary Figure describes the infants with UTI.

CONCLUSION

The incidence of UTI prior to initial neonatal imaging in newborns with AUTD was low. Use of CAP was not associated with UTI incidence after adjusting for UTD severity. Routine use of CAP in newborns with AUTD prior to initial imaging may be of limited benefit in most patients.

Can dynamic ultrasonography replace urodynamics in the follow-up of patients with myelomeningocele? A prospective concurrent study

AIMS

To evaluate the accuracy of dynamic ultrasonography (DUS), as a feasible alternative diagnostic method to identify detrusor overactivity (DO) in patients with neurogenic bladder.

METHODS

We performed concurrent analysis of 81 pairs of urodynamic study (UDS) and DUS, in 63 patients with myelomeningocele (MMC), from June 2014 to February 2017. The assessment focused on bladder behavior during the filling phase, DO evaluation, DO with leakage, compliance, and maximum cystometric capacity (MCC).

RESULTS

Patient age ranged from 3 months to 34 years (median, 84 months); 47.6% were male. Overall, 9.5% of patients had chronic kidney disease, 20.6% had recurrent urinary tract infection, 19.05% had vesicoureteral reflux, and 69.8% had constipation. Anticholinergic therapy was used by 41.3% of patients. DO was observed in 45.67% of patients and DO with leakage in 42.6%. Mean bladder compliance was 10.39 mL/cmH₂ O and normal MCC was 56.79%. DUS had 91.89% sensitivity in identifying DO, 88.64% specificity, 87.18% positive predictive value, 92.86% negative predictive value, and 90.12% accuracy, with a kappa coefficient of 0.8 (P < 0.001).

CONCLUSION

MMC follow-up is essential because urinary parameters can change during patient growth. The standard examination is invasive and has related complications, making noninvasive evaluation a desirable alternative, like DUS. Our data suggest that DO and MCC can be evaluated using DUS in patients with MMC. UDS should be performed in patients with abnormal findings on ultrasound evaluation or those with worsening of urinary tract function.

Postnatal imaging of prenatally detected hydronephrosis-when is voiding cystourethrogram necessary?

OBJECTIVE

To evaluate whether grade 4-5 vesicoureteral reflux (VUR) can be predicted from renal ultrasound (RUS) findings and perform voiding cystourethrograms (VCUGs) only on high-risk patients.

METHODS

The RUS and VCUG images of infants with prenatally detected hydronephrosis admitted to our institution between 2003 and 2013 were re-evaluated. The UTI episodes were collected retrospectively from patient journals. Patients with complex urinary tract anomalies were excluded.

RESULTS

One hundred eighty, 44 female and 136 male, patients (352 renal units (RU)), 23 (30 RU) of them having grade 4-5 VUR, were included. The median age of the patients at the time of the RUS was 1.3 (0.1-3.0) months and the median follow-up time was 2.0 (0.1-11.2) years. In multivariate analysis, a visible ureter (OR 12.72; CI 5.33-32.04, p < 0.001) and shorter renal length (OR 2.67; CR 1.50-4.86, p < 0.001) in RUS predicted grade 4-5 VUR while a visible ureter predicted UTIs (OR 5.75; CI 2.59-12.66, p < 0.001). A three-grade risk score for high-grade VUR was developed based on the RUS findings and the patients were categorized into low-, intermediate-, and high-risk groups. The incidence of grade 4-5 VUR was 2.9% in the low-risk, 12.2% in the intermediate-risk, and 52.2% in the high-risk group. The sensitivity and specificity for detecting grade 4-5 VUR were 79 and 82%, respectively.

CONCLUSIONS

In patients with antenatally detected hydronephrosis, a visible ureter and reduced renal length in RUS are significant risk factors for high-grade VUR. A RUS-based risk scoring would probably reduce the proportion of unnecessary VCUGs.

Potential Novel Biomarkers of Obstructive Nephropathy in Children with Hydronephrosis

Obstructive nephropathy (ON) secondary to the congenital hydronephrosis (HN) is one of the most common causes of chronic kidney disease in children. Neither currently used imaging techniques nor conventional laboratory parameters are sufficient to assess the onset and outcome of this condition; hence, there is a need to prove the usefulness of newly discovered biomarkers of kidney injury in this respect. The purpose of the study was to assess the urinary excretion of alpha-GST, pi-GST, NGAL, and KIM-1 and the serum level of NGAL in children with congenital unilateral hydronephrosis secondary to ureteropelvic junction obstruction. The results were evaluated in relation to severity of HN, the presence of ON, relative function of an obstructed kidney, and the presence of proteinuria. The study comprised 45 children with HN of different grades and 21 healthy controls. Urinary and serum concentrations of biomarkers were measured using specific ELISA kits. Urinary biomarker excretions were expressed as a biomarker/creatinine (Cr) ratio. Patients with the highest grades of HN showed significantly increased values of all measured biomarkers, whereas those with the lowest grades of HN displayed only significant elevation of urinary alpha-GST and the serum NGAL. Urinary NGAL positively correlated with percentage loss of relative function of an obstructed kidney in renal scintigraphy. In patients with proteinuria, significantly higher urinary alpha-GST excretion was revealed as compared to those without this symptom. The ROC curve analysis showed the best diagnostic profile for urinary alpha-GST/Cr and NGAL/Cr ratios in the detection of ON. In conclusion, the results of the study showed that urinary alpha-GST and NGAL are promising biomarkers of ON. Ambiguous results of the remaining biomarkers, i.e., urinary pi-GST and KIM-1, and serum NGAL level may be related to a relatively small study group. Their utility in an early diagnosis of ON should be reevaluated.

Use of MR Urography in Pediatric Patients

PURPOSE OF REVIEW

In this article, we describe the basics of how magnetic resonance urography (MRU) is performed in the pediatric population as well as the common indications and relative performance compared to standard imaging modalities.

RECENT FINDINGS

Although MRU is still largely performed in major academic or specialty imaging centers, more and more applications in the pediatric setting have been described in the literature. MRU is a comprehensive imaging modality for evaluating multiple pediatric urologic conditions combining excellent anatomic detail with functional information previously only available via renal scintigraphy. While generally still reserved for problem solving, MRU should be considered for some conditions as an early imaging technique.

Prenatal Urinary Tract Dilatation

Urinary tract dilatation (UTD) is the most common congenital anomaly detected on prenatal ultrasonography (US), affecting 1% to 3% of all pregnancies. This article focuses on the prenatal detection of UTD and the postnatal evaluation and management based on the UTD grading system risk assessment. Prophylactic antibiotics and postnatal imaging are discussed. The recent management trend is for a more conservative approach to minimize unnecessary testing and exposures to the fetus and neonate while detecting those who may have clinically significant disorder. The renal bladder US remains a critical part of the evaluation and helps guide further investigations.

Continuous Antibiotic Prophylaxis in Pediatric Urology

Continuous antibiotic prophylaxis (CAP) for urinary tract infection prevention in children with vesicoureteral reflux, hydronephrosis, and hydroureteronephrosis is reviewed. A more selective use of CAP is advocated based on a review of known individual risk factors in each of these conditions that subsequently helps identify the children most likely to benefit from CAP. Both short-term and potential long-term side effects of CAP are reviewed, including the impact of prophylactic antibiotics on bacterial resistance and the microbiome. Alternatives to continuous antibiotic prophylaxis including Vaccinium macrocarpon (Cranberry), probiotics, and vaccines are reviewed.

Safe discharge parameters for patients with isolated antenatal hydronephrosis

INTRODUCTION

Antenatal hydronephrosis is a steady source of urology referrals since the era of routine fetal ultrasonography. Although most resolve, there are no guidelines for follow-up.

OBJECTIVE

Our goal is to define safe parameters with which patients can be discharged early and avoid unnecessary follow-up.

METHODS

We retrospectively reviewed all patients referred to a single children's referral hospital center for isolated antenetal hydronephrosis between 2010 and 2012. We looked at patients and renal units separately and divided the cohort into two groups for comparison. Our analysis endpoint is progression. That is, if the initial postnatal anterior-posterior diameter (APD) is less than 10 mm, progression occurs if the APD increases to 10 mm or above upon follow-up. Conversely, if the initial APD is 10 mm or more in at least one renal unit, progression occurs if the APD remains at 10 mm or above upon follow-up.

RESULTS

There majority of the 186 patients and 308 renal units included in the analysis, were classified in the APD less than 10 mm group. Most renal units in the APD of less than 10 mm group were of SFU grades 0-2 (92.1%) and most of the renal units in the APD of 10 mm or greater group were of SFU grades 3-4 (60%) (Table). Only 19 renal units (6.2%) underwent pyeloplasty, and they were all from the APD of 10 mm or greater group and classified as SFU grade 3-4. No renal unit with an APD of less than 10 mm, nor any with an APD of 10 mm or greater and a SFU grade 0-2 underwent pyeloplasty. More than half of the renal units' hydronephrosis resolved in the APD of 10 mm or greater group, in comparison with 96.1% of the APD of less than 10 mm group. On multivariate analysis, patients with an APD of 10 mm or greater were 7.76 times more likely to show progression (p = 0.0006).

CONCLUSION

An initial postnatal APD of 10 mm or greater, with a SFU grade 3-4, merits follow-up. However, all patients with an APD of less than 10 mm, especially when with a SFU grade 1-2, can be safely discharged as they are unlikely to experience complications.

Isolated low grade prenatally detected unilateral hydronephrosis: do we need long term follow-up?

Purpose:

To assess the need for postnatal evaluation and the medium term outcome in patients with isolated unilateral low grade prenatally detected hydronephrosis.

Materials and Methods:

We prospectively selected 424 patients (690 kidney units) with a prenatal diagnosis of urinary tract dilatation between 2010 and 2013. We included only those patients with isolated unilateral low-grade hydronephrosis who underwent at least 2 postnatal ultrasound examinations. The Society for Fetal Urology (SFU) grading system was utilized for assessment of the hydronephrosis. We excluded patients with bilateral dilation or other urological abnormalities. The fate of hydronephrosis including resolution, stability or worsening was documented.

Results:

A total of 66 infants (44 boys and 22 girls) with antenatally diagnosed unilateral urinary tract dilation (23 right and 43 left) were identified. Ultrasounds showed SFU grade 1 hydronephrosis in 32 patients (48%) and SFU grade 2 hydronephrosis in 34 (52%). After a mean follow-up period of 32 months (range 12 to 60), 37 patients (56%) had complete resolution of hydronephrosis while the remaining 29 were stable (44%). None of our patients developed UTIs during follow-up and none required surgical intervention.

Conclusions:

Prenatally detected, isolated unilateral low-grade hydronephrosis usually have a favorable prognosis. All cases in our cohort showed either stability or resolution of hydronephrosis without any harmful consequences. Based on our findings on medium-term in this category of patients, long-term follow-up is not warranted.

Is the renal pyramidal thickness a good predictor for pyeloplasty in postnatal hydronephrosis?

OBJECTIVES

We evaluated the feasibility and value of renal pyramidal thickness (PT) as a predictor of pyeloplasty in high-grade postnatal hydronephrosis.

PATIENTS AND METHODS

We retrospectively reviewed the charts of patients who presented with postnatal hydronephrosis from 2008 to 2013. Included cases had grade 3 or 4 hydronephrosis. We included only units diagnosed as ureteropelvic junction obstruction. Gender, laterality, hydronephrosis side, renogram data, and follow-up data were recorded. Two investigators reviewed all patients' ultrasounds images. We measured PT and pelvic anteroposterior diameter (APD) in the last ultrasound before surgery. For those managed conservatively, measurements were obtained from the ultrasound with worst hydronephrosis. PT was measured in supine position in the middle third of the sagittal plane (Figure). We assessed the reliability of PT measurement using the intraclass correlation coefficient (ICC). Univariate and multivariate analyses were used to correlate the collected parameters to pyeloplasty incidence. Receiver operating characteristic curve was used to evaluate the cutoff value of PT that predicts pyeloplasty.

RESULTS

The total included cases were 155 patients (165 units). One hundred and fourteen units had grade 3 hydronephrosis and 51 units had grade 4 hydronephrosis. Fifty-two cases (55 units) underwent pyeloplasty. The median follow-up period was 37.6 months. PT measurement was reliable (ICC = 0.94). Univariate analysis revealed that SFU grading, APD, PT, T1/2, and MAG-3 curves were associated with surgery. Multivariate analysis showed that PT was a single independent predictor for pyeloplasty. PT ≤ 3 mm had 98.1% sensitivity and 89.7% specificity in predicting pyeloplasty.

DISCUSSION

PT is the first portion of renal parenchyma that is affected in high-grade hydronephrosis. Moreover, it changes little over the first 9 years of life. PT measurement in hydronephrosis was not previously evaluated. We found that PT was easily measured in most kidneys with high negative predictive value. The PT value as an indicator for pyeloplasty should undergo extensive assessment by other institutions with different protocols.

CONCLUSION

Being a slowly growing part of the parenchyma, PT can be a good measurable parameter to predict pyeloplasty. Measurement of PT in hydronephrosis is reliable. PT ≤ 3 mm can predict pyeloplasty with 98.1% sensitivity and 89.7% specificity.

Risk factors for postobstructive diuresis in pediatric patients with ureteropelvic junction obstruction, following open pyeloplasty in three high complexity institutions

INTRODUCTION

Postobstructive diuresis (POD) is a polyuric state in which large quantities of salt and water are eliminated after solving a urinary tract obstruction. These patients are at increased risk of severe dehydration, electrolytic disturbances, hypovolemic shock, and death. Ureteropelvic junction obstruction (UPJO) is the most common etiology of collecting system dilatation in the fetal kidney, and a significant number of patients require pyeloplasty. There are limited data regarding prognostic risk factors for POD in this scenario.

OBJECTIVE

To describe possible clinical risk factors for POD in the pediatric population after open pyeloplasty.

STUDY DESIGN

This was a retrospective case series study of consecutive patients diagnosed with UPJO at three high complexity centers, managed with open pyeloplasty from 2006 to 2016. Multiple qualitative and quantitative variables possibly associated with POD were included according to the literature review. They were statistically analyzed with STATA 14 software.

RESULTS

A total of 88 patients with UPJO following open pyeloplasty were analyzed. Twenty-seven patients (30%) had POD. A tendency to present POD in younger patients was found, with a mean age of 20.2 months vs. 72.3 months. There was also an increased risk of POD in patients with previous diagnosis of tubular acidosis.

CONCLUSIONS

There are no data about prognostic clinical risk factors for POD after open pyeloplasty in the pediatric population. Our study corresponds to one of the larger series reported so far. It suggests that younger patients and patients with a previous diagnosis of tubular acidosis could be at greater risk of POD. Consequently, prospective studies are required for validation of our results, and possible impact on patient follow-up.

99mTc-DTPA Diuretic Renography with 3 hours late output fraction in the evaluation of hydronephrosis in children

Objective:

Dynamic renal scintigraphy complemented by late gravity assisted postvoid images to 60 minutes is a frequently used diagnostic test in the evaluation of hydrone- phrosis. The objective of this study is to evaluate the effectiveness in acquiring images at 180 minutes to calculate the late output fraction (LOF) of ^99mTc-DTPA in the diagno- sis of ureteropelvic junction obstruction (UPJO).

Materials and Methods:

A retrospective study of 177 patients (196 renal units) of sus- pected cases of clinical UPJO was conducted. The patients were submitted to at least two dynamic renal scintigraphies of ^99mTc-DTPA, with the addition of furosemide (F0), with a mean age of 4.3±3.8 years for the first study, and a follow-up of 2.7±2.5 years.

Results:

For diagnosis based on renal curves, a 100% sensitivity, 82.2% specificity, positive predictive value (PPV) of 10.4% and negative predictive value (NPV) of 100% were estimated. For diagnosis based on LOF, a 100% sensitivity, 96.3% specificity, PPV of 35.7% and NPV of 100% were estimated.

Conclusion:

A LOF <10% is indicative of UPJO, and a LOF ≥15% is indicative of no UPJO. The data demonstrate that LOF presents equivalent sensitivity and NPV, and higher specificity and PPV in comparison to diagnosis based on renal curves, and is useful in the evaluation and follow-up of suspected cases of UPJO.

Diuretic renography in hydronephrosis: a retrospective single-center study

PURPOSE

Ureteropelvic junction obstruction (UPJO) is one of the most common causes of hydronephrosis other than transient hydronephrosis. In children with unilateral hydronephrosis, mercaptoacetyltriglycine-3 diuretic renography (MAG₃) is used to calculate differential renal function and to assess drainage. The aim of our study is to examine whether anteroposterior pelvic diameter on renal ultrasound (US) scan can predict both differential renal function (DFR) and obstruction in pediatric patients, and whether an US adequately identifies those patients who need further investigation. We also aimed to design a study with a larger sample size than previous studies investigating the relationship between MAG₃ and US.

METHODS

We retrospectively reviewed the MAG₃, US, dimercaptosuccinic acid scan (DMSA) findings, and medical records of pediatric patients with hydronephrosis and/or atrophy who were at follow-up between January 2013 and December 2016 in our center which is located in the south-east region of Turkey.

RESULTS

Two hundred and twenty-five pediatric patients (M/F = 156/69) with unilateral hydronephrosis but without VUR were enrolled in this study. The mean age of the children was 45.4 ± 48.3 months (range 2-173 months). Sixty-nine patients had obstructive pattern on ^99mTc-MAG₃. With respect to obstructive pattern, there was a significant difference between the hydronephrosis groups both with 15 and 20 mm border. An APD of greater than 20 mm had 15.8 times (95% CI 5.72-43.69) higher likelihood of having obstruction MAG3 findings. On the other hand, an APD of greater than 15 cm had 9.2 times (95% CI 3.01-28.57) higher likelihood of having obstruction MAG₃ findings. The incidence of urinary tract infections was lower than in the obstructive group than the other groups. The regression analysis showed that an APD of greater than 20 mm was a risk factor for low DRF (OR = 5.208, 95% CI 1.529-17.743, p = 0.008). However, the regression analysis showed that an APD of greater than 15 mm was not a risk factor low DRF.

CONCLUSIONS

The combination of ultrasound and MAG₃ provides the necessary anatomical and functional information to follow the degree of obstruction and to decide between surgical intervention and conservative follow-up. Our study supports a threshold of 20 mm rather than 15 mm for severe obstruction and a low DRF. An APD threshold greater than 15 mm did not have a predictive value in DRF estimation.

Prenatal Diagnosis of Urinary Tract Dilation: A Case Study

Fetal urinary tract dilation (UTD), also known as fetal hydronephrosis, is one of the most common sonographically identified malformations in the prenatal period. The leading cause of UTD is a variety of obstructive uropathies. The literature on the management and classification systems for UTD is widespread and varied. Diagnosis by sonography benefits the outcome of the affected fetus because early recognition assists in determining further need for prenatal monitoring and postnatal care.

Transperitoneal Mini-Laparoscopic Pyeloplasty in Flank Position: A Safe Method for Infants and Young Adults

Introduction and Objectives

Open dismembered pyeloplasty has been the gold standard treatment for ureteropelvic junction obstruction in children. Laparoscopic pyeloplasty (LP) is becoming a standard procedure, but its acceptance is slow. We report our method for minilaparoscopy (MLP) in children using a tansperitoneal approach with the patient in the lateral flank decubitus which we found technically advantageous. 

Materials and Methods

Retrospective review of the records of 52 children and adolescents up to 18 years of age who underwent transperitoneal MLP at our institution during March 2012–October 2017 A 5 mm trocar is placed for the camera at the site of the umblicus by open technique, two 3 mm trocars placed in the upper and lower quadrants of the abdomen. No additional ports were necessary. 20cm long, 3-mm-diameter instruments are used. Few cases needed percutaneous fixation of the pelvis. The anastomosis is performed with 5–0 or 6–0 Polyglecaprone 25 (Monocryl®) with 13 mm half circle needle (TF plus) suture cut to 12–14 cm length and introduced through the 5-mm port. Needles are removed through the 3-mm port under direct vision. 

Results

Fifty-two children (53 renal units) with a mean age of 82 months (range 3.5–204), a mean weight of 24,35 kg (range 7–57), and a mean follow-up of 20,44 months (6–60). Nine children were younger than 12 months, and 14 were ≤10kg. Six patients were >50kg. The mean of preoperative grade of dilatation was III (SFU scale) and postoperatively improved to SFU 0,60 (0–2). In 50 (94,3%) of the cases, there was complete resolution of hydronephrosis. There was no conversions to open surgery. Three patients suffered complications Clavien-Dindo Classification IIIb, 2 omental prolapses through a port site in two children which required general anaesthesia and one percutaneous drainage due to a leakage. No reinterventions related to stent complications or obstruction were found. Mean hospital stay was 4,69 (3–14) days. 

Conclusions

The method of mini LP described here has proven efficient and safe. Weight appeared not to be limitation for both groups ≤10 and >50 kg.

Prenatal complicated duplex collecting system and ureterocele-Important risk factors for urinary tract infection

PURPOSE

To evaluate the risk of urinary tract infections (UTIs) in infants with prenatally detected complicated duplex collecting system (CDS) or ureterocele.

MATERIALS AND METHODS

All patients with prenatally detected CDS (n=34) or single system ureterocele (n=7) who were admitted to our institution between 2003 and 2013 were enrolled in this retrospective analysis. Duplex collecting systems with ureterocele (n=13), vesicoureteral reflux (VUR) (n=20) or nonrefluxing megaureter without ureterocele (n=7) were determined as complicated. Twenty-six (63%) patients were females. The prevalence of UTI was compared to 66 controls.

RESULTS

The median follow-up time was 5.5 (1.7-12.2) years. Eighteen (44%) patients and 3 (5%) controls had at least one UTI (p<0.001) at the median age of 0.8 and 0.4years, respectively (p=0.481). Fifty-seven percent of the UTIs were breakthrough infections and 82% of those were non-Escherichia coli infections. UTIs occurred prior to any surgical intervention in 4/13 (31%) patients with ureterocele, in 2/14 (14%) patients with VUR, in 4/7 (57%) patients with both ureterocele and VUR, and in 3/7 (43%) patients with nonrefluxing megaureter without VUR or ureterocele (p-values 0.012, 0.209, 0.001 and 0.010, respectively, compared to controls). Postoperative UTIs were observed in 29% of the girls and in none of the 11 boys (p=0.072). The incidence of UTI after perforation of ureterocele was only 14%.

CONCLUSIONS

Children with prenatally detected ureterocele or duplex collecting system associated with nonrefluxing megaureter are at high risk of UTI despite prophylactic antibiotics. In case of prenatally detected ureterocele we suggest to consider early endoscopic perforation.

LEVEL OF EVIDENCE

III.

Outcomes of Isolated Antenatal Hydronephrosis at First Year of Life

Objectives

To compare the grade of hydronephrosis between the antenatal and first postnatal ultrasound (US) and their clinical outcomes.

Methods

This retrospective study included all cases of isolated hydronephrosis detected by antenatal US from August 2005 to February 2011. Hydronephrosis was classified based on the standard criteria into mild, moderate, or severe. Cases associated with other major congenital anomalies were excluded. All patients were followed-up postnatally and outcomes available were analyzed at one year of age.

Results

A total of 105 cases were included out of which 83 (79.0%) were males and 22 (20.9%) were females with a median gestational age of 38 weeks. First postnatal US of 105 cases showed that 20 (19.0%) were free of hydronephrosis, 39 (37.1%) had mild, 29 (27.6%) moderate, and 17 (16.1%) had severe hydronephrosis. Half (50.4%) of hydronephrosis cases improved in their clinical presentation while 13.3% showed deterioration and 36.3% remained the same. Almost half of all cases (52 cases) were diagnosed by US at the end of first year without any effect on renal function.

Conclusions

Antenatal and postnatal US are sensitive tools for detecting hydronephrosis as well as for postnatal counseling. Fetal anatomy US is usually done at 18 weeks gestation and if this reveals any evidence of hydronephrosis, the patient is followed according to the severity. Postnatal US is not done routinely for cases where hydronephrosis resolves completely during pregnancy. Although newborns with antenatal hydronephrosis due to secondary causes are at greater risk for renal impairment, surgical intervention reserves renal function.

Current State of Fetal Intervention for Lower Urinary Tract Obstruction

PURPOSE OF THE REVIEW

In this article, we explore the origins of intervention of fetal lower urinary tract obstruction, and we specifically discuss the background and recent outcomes of vesicoamniotic shunt placement and fetal cystoscopy. The article seeks to provide a comprehensive overview of the field while bringing the reader quickly up to speed on the pertinent literature and the critical data that are available to guide decision-making regarding intervention.

RECENT FINDINGS

Appropriate patient selection for fetal intervention remains challenging despite advances in prenatal imaging. Both a randomized controlled trial and multiple systematic reviews show evidence of a perinatal survival benefit following fetal intervention but rates of renal morbidity remain very high. Despite 30 years of research, fetal lower urinary tract obstruction remains a difficulty entity to treat. Intervention may lead to survival, but physicians and caregivers must remain alert for the distinct possibility of long-term renal morbidity in survivors.

Standardization of pediatric uroradiological terms: a multidisciplinary European glossary

To promote the standardization of nephro-uroradiological terms used in children, the European Society of Paediatric Radiology uroradiology taskforce wrote a detailed glossary. This work has been subsequently submitted to European experts in pediatric urology and nephrology for discussion and acceptance to improve the quality of radiological reports and communication between different clinicians involved in pediatric urology and nephrology.

Expectant use of CIC in newborns with spinal dysraphism: Report of clinical outcomes

PURPOSE

Report urologic outcomes among newborns with spinal dysraphism managed within an expectant clean intermittent catheterization (CIC) program.

METHODS

Newborns were followed clinically and with serial ultrasound (US). Urodynamics (UD) and dimercaptosuccinic acid (DMSA) renal scan were obtained at 3-6 months, 1 year, 3 years, then as needed. Patients with initial evaluation after 6 months were excluded.

RESULTS

Median follow-up was 3.2 years. 11/102 began catheterization for continence (median 4.0 years) and 47/102 did not start CIC. Of these, 2/58 developed a DMSA abnormality. 44/102 began CIC early, often for elevated storage pressures and febrile urinary tract infection (UTI). Of these, 20/44 developed a DMSA abnormality including 9 who had abnormality detected prior to starting CIC. Being on CIC or starting immediately upon recognition of new hydronephrosis, reflux, elevated filling pressures, or febrile UTI was associated with lower chance of DMSA abnormalities (4/17, 24%) compared to delaying CIC (16/27, 60%) (p= 0.03).

CONCLUSIONS

CIC can be deferred until continence in select infants with a low risk of significant DMSA abnormality. However, immediate initiation of CIC upon recognition of risk factors is recommended as this was associated with fewer DMSA abnormalities than delaying CIC. Recommendations for expectantly-managed patients include close follow-up, serial US and UD, and prompt initiation of CIC upon recognition of new hydronephrosis, reflux, elevated storage pressures, or febrile UTIs.

Society for Fetal Urology Classification vs Urinary Tract Dilation Grading System for Prognostication in Prenatal Hydronephrosis: A Time to Resolution Analysis

PURPOSE

The Urinary Tract Dilation grading system for prenatal hydronephrosis was introduced to address potential shortcomings of the Society for Fetal Urology classification. Hydronephrosis resolution is an important patient outcome and is frequently discussed during family counseling. We compared these 2 grading systems and their ability to predict time to hydronephrosis resolution.

MATERIALS AND METHODS

We prospectively screened 855 patients with prenatal hydronephrosis due to ureteropelvic junction obstruction-like hydronephrosis, nonrefluxing primary megaureter or vesicoureteral reflux between 2009 and 2015. Of the patients 454 were excluded due to surgery, late referral, absence of postnatal dilatation or presence of other anomalies, resulting in 401 eligible patients (of whom 81% were male) to be included for analyses. Hydronephrosis grades collected at baseline and last followup were compared to identify resolution trends through time. Hydronephrosis resolution was defined as renal pelvis anteroposterior diameter 10 mm or less at last followup. Time to resolution was analyzed using Cox proportion regression.

RESULTS

Of 401 patients 328 (82%) had resolution during a mean ± SD followup of 24 ± 18 months (maximum 107). Cumulative resolution rate at 3 years was 98% for Society for Fetal Urology grade I hydronephrosis, 87% for grade II, 76% for grade III and 57% for grade IV. The 3-year hydronephrosis resolution rate was 90% for Urinary Tract Dilation postnatal grade 1 (low risk), 81% for grade 2 (intermediate risk) and 71% for grade 3 (high risk).

CONCLUSIONS

Patients with distinctive baseline hydronephrosis grades (classified by Society for Fetal Urology or Urinary Tract Dilation system) had significantly different resolution times for hydronephrosis (p <0.001). Counseling families regarding time to resolution of prenatal hydronephrosis should remain the same whether using Society for Fetal Urology or Urinary Tract Dilation grading system.

Minimally Invasive Management for Vesicoureteral Reflux in Infants and Young Children

Minimally invasive ureteral reimplantation is an attractive and useful tool in the armamentarium for the management of complicated vesicoureteral reflux (VUR). Subureteric dextranomer/hyaluronic acid injection, laparoscopic extravesical ureteric reimplantation and pneumovesicoscopic intravesical ureteral reimplantation with or without robotic assistance are established minimally invasive approaches to management of VUR. The high cost and the limited availability of robotics have restricted accessibility to these approaches. Laparoscopic and/or robotic ureteral reimplantation continues to evolve and will have a significant bearing on the management of complicated VUR in infants and young children.

Standardization of pediatric uroradiological terms: A multidisciplinary European glossary

To promote the standardization of nephro-uroradiological terms used in children, the European Society of Pediatric Radiology uroradiology taskforce wrote a detailed glossary. This work has been subsequently submitted to European experts in pediatric urology and nephrology for discussion and acceptance to improve the quality of radiological reports and communication among different clinicians involved in pediatric urology and nephrology.

Primary non-surgical management of unilateral ureteropelvic junction obstruction in children: a systematic review

Ureteropelvic junction obstruction (UPJO) is the most common obstructive uropathy and its optimal management remains controversial. However, there is a current trend towards non-surgical management. We aimed to determine the effects of the non-surgical management in children with unilateral UPJO. For a systematic review, we searched MEDLINE, EMBASE, CENTRAL, clinical trials registries, and selected conference proceedings for eligible studies. Any type of study reporting the outcomes renal function, secondary surgical intervention, drainage pattern or hydronephrosis of non-surgical management in children with unilateral UPJO was included. Data from 20 studies were extracted and evaluated by two independent authors. The pooled prevalence was 21% for split renal function deterioration, 27.9% for secondary surgical intervention, 3.2% for progressive hydronephrosis, and 82.2% for improved drainage pattern. Not all patients with surgical intervention regained split renal function from enrolment. Renal imaging methods did not strongly correlate with each other. Many studies had to be excluded because of a lack of detection of an obstruction or mixed populations with bilateral UPJO or other uropathies. The variable definitions of UPJO, different criteria for surgical intervention, incongruity of management protocols, and the imprecise reporting of outcomes were limiting factors in the comparability of the results, leading to heterogeneity in meta-analyses. Although the available evidence cannot recommend or refute the current non-surgical management, the systematic review clarifies aspects of the ongoing controversy by providing realistic estimates for non-surgical management in children with unilateral UPJO. Additionally, it reveals unclear potential risks, particularly for long-term outcomes, which were rarely reported.

Determination of threshold value for follow-up of isolated antenatal hydronephrosis detected in the second trimester

INTRODUCTION

Isolated antenatal hydronephrosis (ANH), defined as a dilation of the renal pelvis (≥5 mm), is one of the most common abnormalities detected on prenatal ultrasound. However, established cut-off values for postnatal follow-up differ between countries and are based on little evidence. The current protocol in the Netherlands for follow-up might be too conservative.

OBJECTIVE

To assess the applicability of a higher threshold for follow-up of isolated antenatal hydronephrosis (ANH) than the current practice, without the risk of missing significant postnatal urinary tract obstruction.

STUDY DESIGN

Retrospective case series on all fetuses with isolated ANH (anteroposterior pelvic diameter (APPD) ≥5 mm) at the second trimester anomaly scan, and diagnosed between 2000 and 2009, in relationship to renal outcome.

RESULTS

A total of 279 infants with second trimester isolated ANH were included. In 201/279 (72%) fetuses, ANH had normalized (APPD <10 mm) before the third trimester scans. Hydronephrosis persisted postnatally in a minority of 56/279 (20.1%). Postnatal assessment showed signs of obstruction in 41/279 (14.7%) infants, duplicated collecting system or vesicoureteral reflux (VUR). Surgery was performed in 18/279 (6.5%) infants. A non-functioning kidney was shown in 6/279 (2.2%) infants with ANH. Mild ANH (APPD <7 mm) during the second trimester (172/279 (61.6%)) never resulted in surgery for renal anomalies or non-functioning kidney. Infants with an APPD ≥10 mm in the second trimester were far more likely to develop renal anomalies or undergo surgery compared with infants with an APPD 7-10 mm. The number of non-functioning kidneys was too low to be conclusive.

CONCLUSIONS

Follow-up ultrasounds for isolated ANH ≥7 mm instead of ≥5 mm at the second trimester scan would have saved 62% of third trimester scans, without missing any infant with a non-functioning kidney, significant obstruction or symptomatic VUR. In view of the results, it is reasonable that referral for follow-up of second trimester ANH is not strictly indicated in cases with an APPD <7 mm.

A Pediatrician's Take on a Few Common Infant Urologic and Gynecologic Issues

Urologic and gynecologic issues are common in a pediatric primary care office. This article focuses on the evaluation and management of a few common diagnoses in infants and young children: fetal hydronephrosis, labial adhesions, physiologic phimosis, and hydrocele. This article can help pediatricians decide when these common issues can be managed in the primary care office and when they need subspecialty guidance. [Pediatr Ann. 2017;46(11):e397-e399.].

The antenatal urinary tract dilation classification system accurately predicts severity of kidney and urinary tract abnormalities

BACKGROUND

Urinary tract dilation (UTD) is a commonly diagnosed prenatal condition; however, it is currently unknown which features lead to benign and resolving or pathologic abnormalities. A consensus UTD classification system (antenatal UTD classification, UTD-A) was created by Nguyen et al. in 2014 [1], but has not yet been validated.

OBJECTIVE

To evaluate the ability of the UTD-A system to identify kidney and urinary tract (KUT) abnormalities, assess whether UTD-A can predict severity of KUT conditions, and perform a cost analysis of screening ultrasound (US).

METHODS

A retrospective single-center study was conducted at an academic medical center. Inclusion criteria were: neonates in the well or sick nursery who had a complete abdominal or limited renal US performed in the first 30 days of life between January 01, 2011 and December 31, 2013. Data were collected on prenatal US characteristics from which UTD-A classification was retrospectively applied, and postnatal data were collected up to 2 years following birth.

RESULTS

A total of 203 patients were identified. Of the 36 abnormal postnatal KUT diagnoses, 90% were identified prenatally as UTD A1 or UTD A2-3. The remaining 10% developed postnatal KUT abnormalities due to myelomeningocele, such as VUR or UTD, which were not evident prenatally. Overall sensitivity and specificity of the UTD-A system was 0.767 (95% CI 0.577, 0.901) and 0.836 (95% CI 0.758, 0.897), respectively, when resolved UTD was counted as a normal diagnosis. Postnatal diagnoses differed by UTD-A classification as shown in the Summary fig. Of all the obstructive uropathies, 90.9% occurred in the UTD A2-3 class and none occurred in UTD-A Normal. Rate of postnatally resolved UTD was significantly higher in the UTD A1 group (78%) compared with UTD A2-3 (31%) or UTD-A Normal (12%, all P < 0.001). There was a notable trend towards more UT surgeries, UTI, and positive VUR among UTD A2-3 patients, but statistical significance was limited by a small number of patients.

CONCLUSIONS

This study found that the UTD-A classification system revealed important differences in the severity of UTD abnormalities. With repeated validation in larger cohorts, the UTD-A classification may be used to offer a prognosis for parents regarding prenatally diagnosed KUT conditions. Larger prospective studies should be designed to validate whether the UTD-A system can predict postnatal events related to UTD morbidity such as need for UT-related surgery or UTI.

Imaging in children with unilateral ureteropelvic junction obstruction: time to reduce investigations?

The objective of the study was the development of an abridged risk-stratified imaging algorithm for the management of children with unilateral ureteropelvic junction obstruction (UPJO). Data on timing, frequency and duration of diagnostic imaging in children with unilateral UPJO was extracted retrospectively. Based on these findings, an abridged imaging algorithm was developed without changing the intended management by the clinicians and the outcome of the individual patient. The potential reduction of imaging studies was analysed and stratified by risk and management groups. The reduction in imaging studies, seen for ultrasound (US) and functional imaging (FI), was 45% each. On average, this is equivalent to 3 US and 1 FI studies less for every patient within the study period. The change was more pronounced in the low-risk groups. Progression of UPJO never occurred after 2 years of age and all secondary surgeries were carried out until the age of 3.

CONCLUSIONS

Although our findings need to be validated by further prospective research, the developed imaging algorithm represents a risk-stratified approach towards less imaging studies in children with unilateral UPJO, and a follow-up beyond 3 years of age should be considered only in selected cases at the discretion of the clinician. What is Known: • ultrasound and functional imaging represent an integral part of therapeutic decision-making in children with unilateral ureteropelvic junction obstruction • imaging studies cannot accurately assess which patients are in need of surgical intervention, therefore close, serial imaging is preferred What is New: • a new, risk-stratified imaging algorithm was developed for the first 3 years of life • applying this algorithm could lead to a considerable reduction of imaging studies, and also the associated risks and health-care costs.

Incidence of urinary tract infections in infants with antenatally diagnosed hydronephrosis-A retrospective single center study

OBJECTIVE

To evaluate the incidence of urinary tract infections (UTIs) in infants with antenatal hydronephrosis (AHN).

MATERIALS AND METHODS

A cohort of AHN patients admitted to our institution between 2003 and 2013 were identified. Altogether 192 patients with nonrefluxing hydronephrosis (HN, n=135), nonrefluxing hydroureteronephrosis (HUN, n=21), or vesicoureteral reflux (VUR, n=36) were identified. Patients with complex anomalies or neonatal decompression of the urinary tract were excluded. Information about UTIs diagnosed among the AHN patients was collected and compared with data from 58 controls.

RESULTS

During the median follow-up time of 2.6 (0.3-11.2) years, 24 (13%) patients (15 (10%) males and 9 (19%) females) and 2 (3%) controls experienced at least one UTI (p=0.033). Eighteen (69%) UTIs were febrile. The males had the first UTI at significantly younger age than the females (0.3, 0.0-1.7years vs. 1.0, 0.4-4.8years, p=0.010). UTI was detected in 15 (63%) patients with grade 4-5 VUR, in 8 (6%) patients with HN, and in one (5%) patient with HUN (p-values <0.001, 0.726 and >0.999 against the controls). None of the patients with grade≤3 VUR had UTI. Fifty-eight percent of the patients with UTI were on antimicrobial prophylaxis. In five (12%) cases UTI appeared within one week after voiding cystourethrography (VCUG).

CONCLUSIONS

Infants with AHN and grade 4-5 VUR had the highest risk of UTI. UTIs tented to be more common in females than in males; however, males experienced UTI at younger age than females. VCUG caused UTI in 2.3% in our material.

LEVEL OF EVIDENCE

III.