Meaning of ureter dilatation during ultrasonography in infants for evaluating vesicoureteral reflux

Does preoperative screening VCUG affect the outcomes and complications of pyeloplasty in patients with ureteropelvic junction obstruction?

INTRODUCTION

The role of voiding cystourethrogram (VCUG) in evaluating vesicoureteral reflux (VUR) in patients with known ureteropelvic junction obstruction (UPJO) remains unclear. While VCUG is frequently performed, the incidence of concomitant VUR and UPJO is low, and VUR is often low-grade with high rates of spontaneous regression.

OBJECTIVE

To analyze the clinical relevance of VCUG in patients with UPJO by determining its incidence and studying the difference in clinical outcomes between patients with known, unknown, and negative VUR.

STUDY DESIGN

Retrospective review of patients with UPJO who underwent pyeloplasty from 2012 to 2020 with <18 years-old, unilateral UPJO, postoperative follow-up of ≥2 months and had at least 1 renal ultrasound (US) after pyeloplasty. Results were compared among 3 groups: patients who underwent VCUG before pyeloplasty and were found to have VUR (group 1), patients who underwent VCUG before pyeloplasty without VUR (group 2), and patients who did not have a VCUG before pyeloplasty (group 3).

RESULTS

A total of 275 patients met the inclusion criteria, of which 21 patients were classified in group 1, 166 patients in group 2, and 88 patients in group 3 (Table). The age at preoperative VCUG was 14.7 ± 32.9 months in group 1 and 15.17 ± 35.8 months in group 2 (p = 0.960). Overall, the incidence of concomitant UPJO and VUR was 11.2%. In group 1 the initial VUR grade was 5 in 2 patients, 4 in 3, 3 in 5, 2 in 7, and 1 in 4 patients. Of these, only 1 patient required ureteral reimplantation after pyeloplasty. Post-pyeloplasty, no significant differences were observed in complications (p = 0.7436), length of follow up (p = 0.3212), SFU grade 4 hydronephrosis (p = 0.2247), postoperative UTIs (p = 0.1047) and pyeloplasty success rate (p = 0.4206) among the 3 groups. Despite the use of antibiotic prophylaxis being significantly different amongst the three groups (p < 0.001), it was not associated with a lower incidence of postoperative UTIs (group 1 p = 0.068, group 2 p = 0.486, group 3 p = 1). In patients with reflux, an increase in age was associated with a decrease in the rates of complications (p = 0.019).

CONCLUSION

We found no significant difference in the outcomes in patients who had a preoperative VCUG as compared to those who did not. The preoperative diagnosis of VUR by VCUG changed the management in less than 1% of the study population and thus its role in patients with UPJO should be reevaluated.

Conflicting views of physicians and surgeons concerning pediatric urinary tract infection: a comparative review

BACKGROUND

A first febrile urinary tract infection (UTI) is a common condition in children, and pathways of management have evolved over time.

OBJECTIVE

To determine the extent to which pediatricians and surgeons differ in their investigation and management of a first febrile UTI, and to evaluate the justifications for any divergence of approach.

MATERIALS AND METHODS

A literature search was conducted for papers addressing investigation and/or management following a first febrile UTI in children published between 2011 and 2021. Searches were conducted on Medline, Embase, and the Cochrane Controlled Trials Register. To be eligible for inclusion, a paper was required to provide recommendations on one or more of the following: ultrasound (US) and voiding cystourethrogram (VCUG), the need for continuous antibiotic prophylaxis and surgery when vesicoureteral reflux (VUR) was detected. The authorship required at least one pediatrician or surgeon. Authorship was categorized as medical, surgical, or combined.

RESULTS

Pediatricians advocated less imaging and intervention and were more inclined to adopt a "watchful-waiting" approach, confident that any significant abnormality, grades IV-V VUR in particular, should be detected following a second febrile UTI. In contrast, surgeons were more likely to recommend imaging to detect VUR (p<0.00001), and antibiotic prophylaxis (p<0.001) and/or surgical correction (p=0.004) if it was detected, concerned that any delay in diagnosis and treatment could place the child at risk of kidney damage. Papers with combined authorship displayed intermediate results.

CONCLUSION

There are two distinct directions in the literature regarding the investigation of an uncomplicated first febrile UTI in a child. In general, when presented with a first febrile UTI in a child, physicians recommend fewer investigations and less treatment, in contrast to surgeons who advocate extensive investigation and aggressive intervention in the event that imaging detects an abnormality. This has the potential to confuse the carers of affected children.

Spontaneous vesicoureteral reflux resolution curves based on ureteral diameter ratio

INTRODUCTION

Various factors influence the clinical course of vesicoureteral reflux (VUR) in the pediatric population. Distal ureteral diameter ratio (UDR) is an objective measure reflective of ureterovesical junction anatomy that has been shown to independently predict both spontaneous resolution and breakthrough febrile urinary tract infection (UTI) in children with primary reflux. UDR resolution curves were created, hypothesizing that a UDR value existed at which spontaneous resolution was unlikely to occur.

MATERIALS AND METHODS

UDR was computed by measuring largest ureteral diameter within the pelvis and dividing by the distance between L1-L3 vertebral bodies. Recursive partitioning with 10-fold cross validation methodology for time to event data, utilizing martingale residuals was used to create high and low risk groups based on UDR, and stratified by age at diagnosis and laterality.

RESULTS

Three hundred and four patients (226 female, 78 male) were analyzed with a mean age at diagnosis of 1.55 ± 1.98 years. Unilateral reflux (p = 0.02), VUR grades 1-3 (p < 0.001), and lower UDR (p < 0.001) were associated with spontaneous resolution on univariate analysis. UDR values were categorized into risk groups based on recursive partitioning. Low risk patients (those with UDR <0.30) achieved VUR resolution faster and with a continuing rate compared to the high-risk group (≥0.30), which had persistent reflux after 3 years [Summary Figure]. When the 0.30 cutoff was applied randomly to patients in test group, the cutoff significantly discriminated between low and high-risk patients (log rank test p = 0.02).

DISCUSSION

Primary VUR is often a self-limiting diagnosis, with conservative management favored in low-risk children, UDR may be used to help distinguish those children who may benefit from intervention. Unlike traditional VUR grading where children with any grade of reflux may spontaneously resolve, there appears to be a consistent UDR cutoff whereby patients are very unlikely to spontaneously resolve, regardless of length of follow-up. Therefore, parents of children with a UDR above the 0.3 cutoff, regardless of VUR grade, may be counselled that VUR is very unlikely to resolve over time - thereby reducing the number of VCUGs and length of time these patients are on prophylactic antibiotic prior to surgical intervention.

CONCLUSIONS

Children with primary VUR and a UDR of greater than 0.30 are significantly less likely to spontaneously resolve regardless of length of follow-up, and resolution after 3 years was rare. UDR provides objective prognostic information facilitating individualized patient management.

Model for predicting high-grade vesicoureteral reflux in young children presenting with febrile urinary tract infection

INTRODUCTION

High-grade vesicoureteral reflux (VUR) is associated with long-term renal outcome, and can be missed if voiding cystourethrogram (VCUG) is not performed. The current febrile urinary tract infection (UTI) guidelines have narrowed down the indications for VCUG. This study aimed to determine the predictors and develop a model to predict high-grade VUR (grade III-V) in young children presenting with febrile UTI.

METHODS

We retrospectively reviewed 324 children aged 2-60 months who presented with first or recurrent febrile UTI and underwent both renal and bladder ultrasonography (RBUS) and VCUG during 2004-2013. Multivariate logistic regression was used to identify independent predictors of high-grade VUR, and a predictive model and scoring system were developed. Sensitivity and specificity of the predictors were evaluated.

RESULTS

Sixty-two (67.4%) of 92 children with VUR were high-grade VUR. The independent risk factors for high-grade VUR were recurrent UTI (p < 0.001), non-Escherichia coli (non-E. coli) pathogen (p = 0.011), and abnormal RBUS (p < 0.001) including pelvicalyceal dilation only (p = 0.003), and with ureteric dilation (p < 0.001). Abnormal RBUS showed highest sensitivity (58.1%), while ureteric dilation had highest specificity (96.6%) to predict high-grade VUR. Combination of these predictors improved the specificity but decreased the sensitivity. The prediction score was calculated, as follows: recurrent UTI = 3 points + non-E. coli = 1 point + pelvicalyceal dilation only = 1 point + pelvicalyceal and ureteric dilation = 3 point. A cutoff score of 1 showed sensitivity of 82.3% and specificity of 63.7%. The specificity would increase (87.8, 92.7, 97.7, 100, 100, and 100%) for higher scores of 2, 3, 4, 5, 6 and 7, respectively.

DISCUSSION

High-grade VUR could be predicted by simple model using single or combined predictors. Sensitivity and specificity varied according to each predictor. The specificity of ureteral dilation was as high as recurrent UTI. The weighing score for each presenting predictor and the summation of the scores provided more detailed in sensitivity and specificity.

CONCLUSIONS

Children with febrile UTI who have the predictor(s) of high-grade VUR are recommended to undergo VCUG. The high-grade VUR prediction score may help for decision-making regarding whether to perform VCUG in a particular child.

The Change in the Renal Pelvis Anterior-Posterior Diameter Between Prevoiding and Postvoiding Status, and Its Correlation With Vesicoureteral Reflux

In this study, our aim was to evaluate the significance of the change in renal pelvis anterior-posterior diameter (RPAPD) before and after micturition between vesicoureteral reflux (VUR)-positive and -negative patients to whom had voiding cystourethrography (VCUG) was performed.In this study, 69 children, age ranging from 0 to 12 years, were included. Before the VCUG imaging, the RPAPD was measured first with a full bladder and then after urination via ultrasound (US). The differences between in RPAPD measurements were noted and values compared made among VUR-positive and -negative children. Data distribution was inhomogeneous, and the Wilcoxon Sign Rank test was utilized instead of Student t test. There was no statistically significant difference in prevoiding and postvoiding RPAPD in VUR (+) and VUR (-) patients (P = 0.672). There was no statistically significant relation between VUR and the presence of hydronephrosis (P = 0.126). Vesicoureteral reflux is more common in patients with urinary tract infections (UTI) (P = 0.001). There was no statistically significant relationship between prevoiding and postvoiding RPAPD change and VUR diagnosis (P = 0,164).Ultrasound is the modality of choice for urinary system evaluation. Diagnosis of hydronephrosis via US is not sufficient in predicting VUR; however, indirect findings may reveal the diagnosis. A decrease in RPAPD in postvoiding US evaluation may not rule out the VUR diagnosis for this reason further imaging modalities, such as VCUG, should be taken into consideration for the patients with clinical suspicion.

New trends in voiding cystourethrography and vesicoureteral reflux: Who, when and how?

Vesicoureteral reflux, retrograde flow of urine from the bladder into the upper urinary tract, is one of the most common urological diagnoses in the pediatric population. Diagnosis and subsequent management of urinary reflux have become increasingly debated in the past decade, with divergent opinions over which patients should be evaluated for reflux, and when detected, which children should receive intervention. Although some argue that vesicoureteral reflux is a "phenotype" that often resolves without intervention, others contest that untreated reflux has the potential to cause irreversible renal damage over time. Voiding cystourethrogram images the urethra and bladder during both bladder filling and emptying, as well as the ureters and kidneys when reflux is present, and is considered the gold standard for diagnosing vesicoureteral reflux. Once detected, therapeutic options for urinary reflux are diverse, ranging from observation with or without low-dose antibiotic prophylaxis to a variety of operative interventions. Management should be based on a multitude of factors including patient age, risk of subsequent urinary tract infections, risk of renal parenchymal injury, a given child's projected clinical course and parental preference. Over the past two decades, investigators have elucidated many crucial voiding cystourethrogram findings in addition to grade that provide significant prognostic information and are useful in determining the best course of action for a child on a more individualized basis.

Influence of postnatal hydroureter in determining the need for voiding cystourethrogram in children with high-grade hydronephrosis

Objective

To evaluate the utility of hydroureter (HU) to identify high-grade vesico-ureteric reflux (VUR) in patients with high-grade postnatal hydronephrosis (PH).

Patients and methods

We retrospectively reviewed patients’ charts that had antenatal hydronephrosis from 2008 to 2014. Patients were excluded if they presented with febrile urinary tract infection (fUTI), neurogenic bladder, posterior urethral valve, multi-cystic dysplastic kidney, and multiple congenital malformations. We reviewed postnatal ultrasonography images and patients with Society of Fetal Urology (SFU) Grades 3 and 4 hydronephrosis with a renal pelvic antero-posterior diameter of ≥10 mm were included. The ureter was assessed and considered dilated if the ureteric diameter was  ≥4 mm. The voiding cystourethrogram (VCUG) studies, fUTI incidence, and surgical reports were reviewed.

Results

Of the 654 patients reviewed, we included 148 patients (164 renal units) of whom 113 (76.4%) were male and 35 (23.6%) female. SFU Grade 3 PH was identified in 49% of the renal units, with the remaining 51% being SFU Grade 4. HU was found in 50/164 renal units and was not detected in the remaining 114 units. VUR was diagnosed in four units (3.5%) without HU (low-grade VUR); whilst it was detected in 19 units (38%) with HU (72.7% were high-grade VUR) (P < 0.001). VUR was diagnosed on the contralateral side in four/105 patients with PH without HU and diagnosed in 10/43 patients with PH with HU (P < 0.001). During a median follow-up of 25.9 months, none of the renal units that had VUR without HU developed UTI or had surgeries.

Conclusion

Low-grade uncomplicated VUR was diagnosed in 3.5% of renal units without HU. Our results support limiting the use of VCUG to renal units with PH if associated with HU.