Can distal ureteral diameter measurement predict primary vesicoureteral reflux clinical outcome and success of endoscopic injection?

Ultrasound-based predictive indicators for treatment outcomes in pediatric vesicoureteral reflux

PURPOSE

To evaluate the effectiveness of preoperative ultrasound (US) measurements in predicting pediatric vesicoureteral reflux (VUR) treatment outcomes.

METHODS

This prospective study enrolled 35 patients (53 renal units) aged 1-16 years who underwent subureteric injection therapy for primary VUR between July 2020 and June 2022. Preoperative ultrasound examinations measured the bladder wall thickness at the ureteral orifice, ureteral submucosal tunnel length, distal ureteral diameter, patient demographics, VUR grade, presenting complaints, bladder-bowel dysfunction, and renal scarring, and the impact of these variables on treatment success was analyzed.

RESULTS

Among the patients, 91.4% were female, with a mean age of 6.83 ± 3.84 years. A comparison between the treatment success and failure groups revealed no significant differences in the age, sex, VUR grade, laterality, bilaterality, presenting complaints, bladder-bowel dysfunction, bladder wall thickness, or distal ureteral diameter (p > 0.05). However, renal scarring occurred in 16 (38.1%) patients in the treatment success group and 10 (90.9%) in the treatment failure group (p = 0.002). The treatment failure group had shorter detrusor-to-ureteral orifice distances and smaller detrusor-ureteral orifice distance-to-distal ureteral diameter (D/U) ratios than that of the success group (p = 0.004 and p = 0.006, respectively). Patients with a detrusor-to-ureteral orifice distance < 7.4 mm had an 81.82% likelihood of treatment failure.

CONCLUSION

Ultrasound measurements of the detrusor-to-ureteral orifice distance and D/U ratio proved reliable in predicting the success of endoscopic subureteric injection therapy for VUR.

The impact of the distal ureteral diameter ratio, bladder volume at onset of vesicoureteral reflux, and/or grade in predictive models of clinical outcomes in children with vesicoureteral reflux

PURPOSE

Vesicoureteral reflux (VUR) grade has been used as a primary factor in assessing a child's risk of clinical outcomes. Unfortunately, grade has poor inter-observer reliability. We hypothesized that more objective and reliable VCUG parameters including the distal ureteral diameter ratio (UDR) and volume at onset of VUR (Vol) may either augment or replace the current grading system to provide more reliable prediction of clinical outcomes.

MATERIALS AND METHODS

Multivariate clinical outcome models were analyzed to assess the impact on predictive accuracy by the addition of voiding cystourethrogram (VCUG) data including grade, UDR, and Vol, alone or in combinations. Clinical variables from retrospective review of 841 children's records included age, gender, presentation, VUR laterality, bowel and bladder dysfunction, history of febrile urinary tract infection (UTI), and number of UTIs. The primary outcomes assessed included VUR resolution or persistence and need for operative intervention.

RESULTS

Grade, UDR, and Vol were independent predictors of resolution and operative intervention. Vol increased predictive accuracy in resolution models with grade or UDR alone; however, no significant difference occurred in models with the substitution of grade with UDR.

CONCLUSIONS

A more reliable classification system for VUR, with improved predictive accuracy regarding clinical outcomes, may be developed incorporating UDR and Vol. Whether VUR grade can be completely replaced by Vol and UDR measurements requires further evaluation with larger number of patients.

Update and Summary of the European Association of Urology/European Society of Paediatric Urology Paediatric Guidelines on Vesicoureteral Reflux in Children

BACKGROUND AND OBJECTIVE

The prescriptive literature on vesicoureteral reflux (VUR) is still limited and thus the level of evidence is generally low. The aim of these guidelines is to provide a practical approach to the treatment of VUR that is based on risk analysis and selective indications for both diagnostic tests and interventions. We provide a 2023 update on the chapter on VUR in children from the European Association of Urology (EAU) and European Society for Paediatric Urology (ESPU) guidelines.

METHODS

A structured literature review was performed for all relevant publications published from the last update up to March 2022.

KEY FINDINGS AND LIMITATIONS

The most important updates are as follows. Bladder and bowel dysfunction (BBD) is common in toilet-trained children presenting with urinary tract infection (UTI) with or without primary VUR and increases the risk of febrile UTI and focal uptake defects on a radionuclide scan. Continuous antibiotic prophylaxis (CAP) may not be required in every VUR patient. Although the literature does not provide any reliable information on CAP duration in VUR patients, a practical approach would be to consider CAP until there is no further BBD. Recommendations for children with febrile UTI and high-grade VUR include initial medical treatment, with surgical care reserved for CAP noncompliance, breakthrough febrile UTIs despite CAP, and symptomatic VUR that persists during long-term follow-up. Comparison of laparoscopic extravesical versus transvesicoscopic ureteral reimplantation demonstrated that both are good option in terms of resolution and complication rates. Extravesical surgery is the most common approach used for robotic reimplantation, with a wide range of variations and success rates.

CONCLUSIONS AND CLINICAL IMPLICATIONS

This summary of the updated 2023 EAU/ESPU guidelines provides practical considerations for the management and diagnostic evaluation of VUR in children.

ADVANCING PRACTICE

For children with VUR, it is important to treat BBD if present. A practical approach regarding the duration of CAP is to consider administration until BBD resolution.

PATIENT SUMMARY

We provide a summary and update of guidelines on the diagnosis and management of urinary reflux (where urine flows back up through the urinary tract) in children. Treatment of bladder and bowel dysfunction is critical, as this is common in toilet-trained children presenting with urinary tract infection.

Update on imaging recommendations in paediatric uroradiology: the European Society of Paediatric Radiology workgroup session on voiding cystourethrography

Voiding cystourethrography (VCUG) is a fluoroscopic technique that allows the assessment of the urinary tract, including the urethra, bladder, and-if vesicoureteral reflux (VUR) is present-the ureters and the pelvicalyceal systems. The technique also allows for the assessment of bladder filling and emptying, providing information on anatomical and functional aspects. VCUG is, together with contrast-enhanced voiding urosonography (VUS), still the gold standard test to diagnose VUR and it is one of the most performed fluoroscopic examinations in pediatric radiology departments. VCUG is also considered a follow-up examination after urinary tract surgery, and one of the most sensitive techniques for studying anatomy of the lower genitourinary tract in suspected anatomical malformations. The international reflux study in 1985 published the first reflux-protocol and graded VUR into five classes; over the following years, other papers have been published on this topic. In 2008, the European Society of Paediatric Radiology (ESPR) Uroradiology Task Force published the first proposed VCUG Guidelines with internal scientific society agreement. The purpose of our work is to create a detailed overview of VCUG indications, procedural recommendations, and to provide a structured final report, with the aim of updating the 2008 VCUG paper proposed by the European Society of Paediatric Radiology (ESPR). We have also compared VCUG with contrast-enhanced VUS as an emergent alternative. As a result of this work, the ESPR Urogenital Task Force strongly recommends the use of contrast-enhanced VUS as a non-radiating imaging technique whenever indicated and possible.

Dynamic and static ultrasound features predictive of vesicoureteral reflux and renal damage in children and adolescents with neurogenic bladder

PURPOSE

This study aimed to analyze the diagnostic accuracy of dynamic and static ultrasound (DSUS) in detecting vesicoureteral reflux (VUR) and renal scarring in a cohort of children with neurogenic bladder (NB).

MATERIALS AND METHODS

A retrospective, longitudinal, observational study was conducted using the Reporting Diagnostic Accuracy Studies guideline. The DSUS (index test) data were compared with voiding cystourethrography (VCUG) and renal scintigraphy 99mTc-dimercaptosuccinic (reference tests). Overall performance for predicting VUR and renal scarring was assessed using renal pelvic diameter (RPD)/distal ureteral diameter and renal parenchymal thinning on DSUS, respectively.

RESULTS

A total of 107 patients (66 girls, median age 9.6 years) participated. Seventeen patients (15.9%) presented VUR, eight bilateral. For overall reflux grade, the AUC was 0.624 for RPD and 0.630 for distal ureteral diameter. The diagnostic performance for detecting high-grade VUR was slightly better for DSUS parameters. The AUC was 0.666 for RPD and 0.691 for distal ureteral diameter. The cut-offs of 5 mm for RPD and 6.5 mm for distal ureteral diameter presented the best diagnostic odds ratio (DOR) to identify high-grade VUR. The increase of RPD during detrusor contractions showed an accuracy of 89.2%. The thinness of renal parenchyma presented an accuracy of 88% for renal scarring.

CONCLUSION

DSUS predicts VUR and renal scarring in children with NB with fair to good accuracy, and all measurements exhibited a high negative predictive value (NPV). The increase in RPD during voiding or detrusor contractions proved to be the most accurate parameter for indicating the presence of VUR in this study.

Does the distal ureteral diameter ratio (UDR) matter in the surgical management of vesicoureteral reflux in children?

PURPOSE

To evaluate UDR reliability, sensitivity, specificity and to identify the best treatment basing on UDR among single or double endoscopic injections and ureteral reimplantation.

METHODS

Data of patients affected by primary VUR and treated by endoscopic injection over a 10 years period were retrospectively analyzed. Two radiologist attributed reflux grade and UDR on voiding cystourethrogram twice and blinded. Follow-up focused on resolution after 1 or 2 endoscopic injections. Relation between UDR, reflux grade and outcomes were analyzed.

RESULTS

Patient enrolled were 198. Low grade VUR was present in 24.8%, grade 3 in 41.6%, grade 4-5 in 33.6%. Resolution after one injection was obtained in 88 patients; among 110 not resolved 104 cases had a second injection. Success after 2 injections was reported in 138 cases. UDR showed a higher reliability compared with reflux grade both in intra than inter-reader measurement (ICC > 90%). Success after 1 or 2 injections was reported for UDR < 0.33 and UDR < 0.47 respectively.

CONCLUSION

UDR shows to be a more reliable measurement that allows for an objective estimation of VUR severity and prognosis. It represents a quantitative parameter that might be useful to identify patients who may benefit endoscopic or surgical treatment, avoiding unnecessary under or over-treatment.

Vesicoureteral Reflux: Current Care Trends and Future Possibilities

Although investigations over the past 2 decades have improved our understanding of the natural history of vesicoureteral reflux (VUR) and helped identify those at higher risk of both VUR itself as well as its potential severe sequelae, debate exists regarding key aspects of care, including when to perform diagnostic imaging and which patients benefit from continuous antibiotic prophylaxis. Artificial intelligence and machine learning have the potential to distill large volumes of granular data into practical tools that clinicians can use to guide diagnosis and management decisions. Surgical treatment, when indicated, remains highly effective and is associated with low morbidity.

The ureteral diameter ratio as a predictive factor in renal scarring associated with primary vesicoureteral reflux

INTRODUCTION

The ureteral diameter ratio (UDR) is reported to be effective in predicting the outcomes of vesicoureteral reflux (VUR) in several studies.

OBJECTIVE

The objective of the current study was to compare the risk of scarring in patients with VUR relative to UDR and the VUR grade. We also aimed to demonstrate other associated risk factors in scarring and investigate the long-term complications of VUR and their relationship with UDR.

STUDY DESIGN

Patients diagnosed with primary VUR were retrospectively enrolled in the study. UDR was calculated by dividing the largest ureteral diameter (UD) by the distance between L1-L3 vertebral bodies. Demographic and clinical data, laterality, VUR grade, UDR, delayed upper tract drainage on voiding cystourethrogram, recurrent urinary tract infections (UTI), and long-term complications of VUR were compared between the patients with and without renal scars.

RESULTS

A total of 127 patients and 177 renal units were included in the study. There was a significant difference between the patients with and without renal scars according to age at diagnosis, bilaterality, reflux grade, UDR, recurrent UTI, bladder bowel dysfunction, hypertension, decreased estimated glomerular filtration rate, and proteinuria. The logistic regression analysis revealed that UDR had the highest odds ratio among the factors affecting scarring in VUR.

DISCUSSION

VUR grading based on the evaluation of the upper urinary tract is one of the most important predictors for treatment options and prognosis. However, it is more likely to reflect ureterovesical junctional anatomy and function, which play a crucial role in the pathogenesis of VUR.

CONCLUSION

UDR measurement seems to be an objective method that can help clinicians predict renal scarring in patients with primary VUR.

Endoscopic injection of bulking agents in pediatric vesicoureteral reflux: a narrative review of the literature

In the last 20 years, endoscopic injection (EI) has affirmed as a valid alternative to open surgery for management of pediatric vesicoureteral reflux (VUR). This study aimed to investigate and discuss some debated aspects such as indications, bulking agents and comparison, techniques of injection and comparison, predictive factors of success, use in specific situations. EI is minimally invasive, well accepted by patients and families, with short learning curve and low-morbidity profile. It provides reflux resolution rates approaching those of open reimplantation, ranging from 69 to 100%. Obviously, the success rate may be influenced by several factors. Recently, it is adopted as first-line therapy also in high grade reflux or complex anatomy such as duplex, bladder diverticula, ectopic ureters. The two most used materials for injection are Deflux and Vantris. The first is absorbable, easier to inject, has lower risk of obstruction, but can lose efficacy over time. The second is non-absorbable, more difficult to inject, has higher risk of obstruction, but it is potentially more durable. The two main techniques are STING and HIT. To date, the ideal material and technique of injection has not yet clearly established, but the choice remains dependent on surgeon's preference and experience.

The additive impact of the distal ureteral diameter ratio in predicting early breakthrough urinary tract infections in children with vesicoureteral reflux

INTRODUCTION

Many factors influence patient and provider decisions to surgically correct vesicoureteral reflux (VUR), including risk of breakthrough febrile urinary tract infections and likelihood of spontaneous resolution. Ureteral diameter ratio has been shown in several studies to be more predictive than reflux grade with regard to breakthrough urinary tract infection (UTI). We developed and investigated the accuracy of a computational model for predicating febrile breakthrough urinary tract infection within 13 months of starting prophylactic antibiotics in children with VUR.

OBJECTIVE

The aim of this study was to validate a model for evaluating the impact of distal ureteral diameter ratio (UDR) in predicting early breakthrough urinary tract infections in children with VUR.

STUDY DESIGN

Following a retrospective review, we recorded patient demographics, presenting symptoms, VUR grade, laterality, VUR during filling or voiding, initial bladder volume at the onset of VUR, ureteral duplication, voiding dysfunction, distal ureteral diameter ratio, and number of UTIs prior to VUR diagnosis. NeUROn++, a set of C++ programs, was used to model each data set using logistic regression and neural networks with different architectures.

RESULTS

After exclusions, 136 children (93 girls and 43 boys) diagnosed with primary VUR had detailed VCUG and UDR data available. Fourteen children (10.3%) experienced breakthrough febrile UTI events within 13 months of VUR diagnosis. There was a significant association with UDR and breakthrough UTI (p = 0.008). Various computational prediction models for the outcome of breakthrough UTI were developed and evaluated. The computational model that fit best was a model using all variables with an ROC of 0.802.

DISCUSSION AND CONCLUSIONS

Clinicians and parents often opt for intervention based on likelihood of spontaneous resolution of VUR as well as clinical course, thereby placing an emphasis on the ability to predict likelihood of breakthrough UTI infections. Our statistical analysis and prediction models further confirm UDR as an important variable predictive of breakthrough UTIs within the first 13 months of beginning prophylactic antibiotics. Furthermore, we developed a neural network model incorporating UDR and grade with an ability to yield the greatest accuracy of any breakthrough UTI predictive calculator to date at 80%.

Additional VCUG-related parameters for predicting the success of endoscopic injection in children with primary vesicoureteral reflux

INTRODUCTION AND OBJECTIVE

Prediction of vesicoureteral reflux (VUR) prognosis and decision for treatment are usually made according to the reflux grading classification. But the management of VUR is still controversial since there are difficulties in distinguishing reflux grade due to inter- and intra-observer variations. Previous studies have demonstrated that the distal ureteral diameter ratio (UDR) on voiding cystourethrography (VCUG) may be more predictive for clinical prognosis than reflux grade. We aimed to predict the success of endoscopic injection in primary VUR by creating new models that include other additional parameters (timing of reflux, delayed post-voiding contrast drainage of the upper urinary tract) as well as UDR.

STUDY DESIGN

A total of 200 patients aged 2-15 years with primary VUR undergoing endoscopic injection were retrospectively evaluated. Demographic and clinical data for a total of 248 renal units were recorded. Besides reflux grade and laterality, distal ureteral diameter, UDR, timing of reflux [early filling, late filling or voiding] and presence of contrast delay in upper tract drainage were also assessed on VCUG. According to the complete resolution of VUR on the control VCUG at the postoperative 3rd month, the renal units were divided into two main groups: successful (n = 171, 68.9%) and unresolved (n = 77, 31.1%) RESULTS: The failure rate of endoscopic injection was found to be 4.068 times greater with early filling reflux on VCUG, 3.076 times greater with UDR>0.24, 2.745 times greater with delayed contrast drainage of the upper urinary tract, 2.666 times greater with the presence of scar in DMSA, 2.493 times greater with bladder-bowel dysfunction and 2.341 times greater with febrile urinary tract infection. We also observed that a model in which all VCUG-related parameters were combined provided a better estimation of endoscopic injection outcomes compared to only the reflux grade (AUC: 0.903 vs. 0.604, respectively).

DISCUSSION

Distal ureteral dilatation is considered to be a more decisive factor for clinical outcomes of primary VUR rather than upper urinary tract dilatation since ureterovesical junction anatomy plays a more important role in primary VUR pathophysiology. Studies investigating new prediction models on this topic have recently become more popular. However, a consensus has not yet been achieved.

CONCLUSION

We consider that UDR level, the timing of reflux and delayed upper tract drainage on VCUG may be more predictive parameters of endoscopic injection success compared with reflux grade, and could facilitate selecting the best candidates for surgery.

Management of Vesicoureteral Reflux: What Have We Learned Over the Last 20 Years?

Vesicoureteral reflux (VUR) is associated with increased risks of urinary tract infection, renal scarring and reflux nephropathy. We review advancements over the last two decades in our understanding and management of VUR. Over time, the condition may resolve spontaneously but it can persist for many years and bladder/bowel dysfunction is often involved. Some factors that increase the likelihood of persistence (e.g., high grade) also increase the risk of renal scarring. Voiding cystourethrography (VCUG) is generally considered the definitive method for diagnosing VUR, and helpful in determining the need for treatment. However, this procedure causes distress and radiation exposure. Therefore, strategies to reduce clinicians' reliance upon VCUG (e.g., after a VUR treatment procedure) have been developed. There are several options for managing patients with VUR. Observation is suitable only for patients at low risk of renal injury. Antibiotic prophylaxis can reduce the incidence of UTIs, but drawbacks such as antibiotic resistance and incomplete adherence mean that this option is not viable for long-term use. Long-term studies of endoscopic injection have helped us understand factors influencing use and the effectiveness of this procedure. Ureteral reimplantation is still performed commonly, and robot-assisted laparoscopic methods are gaining popularity. Over the last 20 years, there has been a shift toward more conservative management of VUR with an individualized, risk-based approach. For continued treatment improvement, better identification of children at risk of renal scarring, robust evidence regarding the available interventions, and an improved VUR grading system are needed.

Endoscopic Injection Treatment of Vesicoureteral Reflux in Children: Meeting with the Factors Involved in the Success Rate

The challenges and controversies in vesicoureteral reflux intervention guidelines resulted in a more individualized treatment planning. Endoscopic injection therapy is now widely used and is considered preferable, but still remains less successful than ureteral reimplantation. Τhe endoscopic vesicoureteral reflux approach should be risk-adapted to current knowledge, so more experience and longer-term follow-up are needed. The precise of preoperative, intraoperative, and postoperative factors that affecting endoscopic injection therapy success rates and outcome have not yet been clearly determined. The aim of this study was to investigate these associated factors. Although the reflux grade is the most well-known factor that can affect the success of the procedure, there is no agreement on which factors are the most influential for the efficacy of endoscopic reflux treatment. So, we carried out a broad review of published papers on this topic, and we presented all the potential predictive variables of endoscopic reflux resolution in children.