Long-term upper and lower urinary tract functions in children with posterior urethral valves

Posterior urethral valve in thai boys

BACKGROUND

Posterior urethral valve (PUV) is the most common congenital bladder outlet obstruction in boys, causing renal damage beginning in utero. There are scarce data from Thailand regarding the long-term outcomes of PUV in boys, thus the aim of this study was to examine the presentation, clinical course, complications, outcomes and renal survival in PUV boys.

METHODS

We reviewed the medical records of PUV boys treated at the Pediatric Nephrology Clinic, Prince of Songkla University, Thailand, over a 30-year-period.

RESULTS

Seventy-seven PUV boys were identified, with a median age at diagnosis of 4.8 months. The most common presentations were urinary tract infection (UTI), poor urine stream and urinary dribbling in 26 (33.8%), 19 (24.7%) and 11 (14.3%) boys, respectively. Renal ultrasound results in 70 boys showed 8 (11.4%) unilateral and 56 (80%) bilateral hydronephroses. Of 72 voiding cystourethrograms, 18 (25.0%) showed unilateral and 22 (30.6%) bilateral vesicoureteral refluxes. 99mTc dimercaptosuccinic acid renal scans in 30 boys showed 12 (40%) unilateral and 8 (26.7%) bilateral renal damage. Fifty-nine (76.6%) boys had 149 UTIs; 42 (54.4%) had recurrent UTI. Forty-eight boys had valve ablation at the median age of 30.3 months. 22 boys (28.6%) developed chronic kidney disease (CKD) at a median age of 15.0 years.

CONCLUSION

Of 77 PUV Thai boys, UTI was the most common presentation. Recurrence of UTI and CKD was the most common consequence. Lifelong follow-up for renal and bladder functions is essential for all PUV patients.

Does VURD syndrome impact voiding efficiency in posterior urethral valves?

INTRODUCTION

There is debate regarding the effect of VURD syndrome, consisting of vesicoureteral reflux (VUR) and ipsilateral kidney dysplasia, on long-term outcomes in boys with posterior urethral valve (PUV). Here, we assessed whether VURD syndrome played a "protective" role on long-term bladder outcomes and voiding efficiency in boys with PUV.

MATERIALS AND METHOD

A retrospective chart review was conducted for toilet-trained children with PUV managed at our institution between 2000 and 2022, only excluding cases without recorded uroflowmetry studies. Patients were stratified by VUR status and by the presence of VURD syndrome (high-grade VUR + ipsilateral kidney dysplasia). Outcomes included initial and final uroflowmetry parameters, and initiation of clean-intermittent catheterization (CIC).

RESULTS

We identified a total of 101 patients who met study inclusion criteria, with an overall median follow-up of 114 months (IQR 67, 169). The median age of first and last uroflowmetry was 57 months (IQR 48, 82) and 120 months (IQR 89, 160), respectively. Patients with VURD syndrome had similar flow velocity, post-void residuals, and bladder voiding efficiency to other PUV patients at last follow-up uroflowmetry. On survival analysis, patients with VURD syndrome had no significant difference in risk of requiring CIC compared to patients without pop-offs (p = 0.06).

DISCUSSION

Like more contemporary studies on pressure pop-offs, we show that this population is not at higher risk of poorer voiding and intermittent catheterization than others. VURD syndrome does not confer protection against poorer bladder function. Instead, our study suggests an independent association between kidney dysplasia and bladder outcomes which requires further attention.

CONCLUSIONS

Among boys with PUV, VURD syndrome was not associated with significantly different uroflowmetry findings or rates of CIC by last follow-up.

Evaluating the impact of pop-off mechanisms in boys with posterior urethral valves

INTRODUCTION

Posterior urethral valves are urethral leaflets that cause Lower Urinary Tract Obstruction (LUTO) in boys and are associated with congenital renal dysplasia and abnormal bladder function. They affect 1:4,000 to 1:25,000 births and can be responsible for End-Stage Renal Failure in childhood. There have been several studies on the effect of pop-off mechanisms in boys with posterior urethral valves, but results are contradictory. We aimed to assess and discuss the effect of pop-off mechanisms on renal function in a large cohort of patients.

PATIENTS AND METHOD

Boys with PUV with and without pop-off mechanisms (urinoma, VURD or giant bladder diverticula) were divided into three severity groups for renal function according to their nadir creatinine (low-risk NC < 35 μmol/L, intermediate-risk NC between 35 and 75 μmol/L, and high-risk NC > 75 μmol/L). We compared children with and children without pop-off mechanisms for mean renal function as well as patient distribution within each severity group.

RESULTS

We included 137 boys of which 39 had a pop-off mechanism. Patients had complete data for at least 5 years follow-up. Though there was no significant statistical difference in mean renal function between the pop-off and non-pop-off group, patient distribution within each severity group varied according to whether patients had a pop-off mechanism or not.

CONCLUSION

Though there was no significant difference in mean renal function between boys with and without pop-off mechanisms, it is possible that these are two different patient populations and direct comparison is not possible.

Renal, Bladder and Sexual Outcomes in Adult Men with History of Posterior Urethral Valves Treated in Childhood

OBJECTIVE

To determine the adulthood outcomes of bladder, kidney, and sexual functions of posterior urethral valve (PUV) patients.

MATERIALS AND METHODS

The records of patients who were treated for PUV between 1980, and 2001 and aged ≥18 years by the end of 2019 were retrospectively reviewed. Patients with complete adulthood data were included in the study. Renal, bladder, and sexual functions were assessed. Adulthood uroflowmetry results of 22 patients were also evaluated.

RESULTS

Thirty-nine patients with complete adulthood data out of 89 were included. The median follow-up time was 22.7 years (15-33 years). Median age at initial surgery for PUV was 36 months (1-168 months), and median age at last follow-up was 26 years (18-46 years). Lower urinary tract dysfunction was noted in 15 (38%) patients. In 22 patients (56%) with uroflowmetric analyses, median values of Q_max, voided volume, and post voiding residual urine volume were 20.5 mL/sec (7-43 mL/sec), 389 mL (154-1750 mL), and 18.5 mL (range 0-190 mL), respectively. Nineteen patients (48.7%) had normal glomerular filtration rate, 2 patients (5.1%) had chronic kidney disease, and the remaining 18 patients (46.1%) had end stage renal disease, 14 (35.9%) of whom underwent renal transplantation. Thirty-two patients (82%) had sexual function evaluation, none of which reported erectile dysfunction. However, 4 patients (12.5%) reported slow ejaculation. Five patients fathered a child whereas infertility was observed in 2 patients.

CONCLUSION

After 2 decades, glomerular filtration rate was normal almost in half of the PUV patients while lower urinary tract dysfunction was detected in 38%. Furthermore, erectile dysfunction was rare.

The posterior urethral valves revisited: embryological correlation, clinical classification, and risk stratification of the spectrum

Background

The diagnosis of posterior urethral valves (PUV) encompasses a vast spectrum of disease with variable severity and clinical features. It is vital to understand the extent of developmental insult and to define the different distinct entities grouped together under the diagnostic umbrella of PUV. This would help to determine the severity of the disease, enable better prognostication, and optimize therapy. The objective of this study is to analyze the variable features of PUV and correlate the different manifestations with the embryological development of the urinary system. The possible developmental basis of anomalies in PUV is analyzed, as recognition of the underlying defect would help to determine the severity of the disease. A clinical classification and a risk stratification approach encompassing the spectrum of PUV is proposed, to help define diagnosis and guide prognosis. A combined retrospective and prospective analysis of cases diagnosed as PUV at the tertiary teaching institute over a 5-year period from July 2014 to July 2019 was done. The outcome of selected cases was analyzed, based on the risk group stratification.

Results

The incidence of major complications during follow-up in each risk group was assessed individually and found to be highest in the high-risk group (92%), which was significantly higher than the other groups. The intermediate risk group was found to have a complication rate of 38%, while the low-risk group had only 12.5% complication rate. The three key concepts addressed in this study pertain to the embryological basis of PUV, the necessity of a clinical subdivision of patients, and the possibility of risk stratification based on clinical criteria. The limited review of institutional series is added to highlight the method of risk stratification and its probable utility.

Conclusions

The most critical factors to be accounted for in the diagnosis and management of PUV are the definition of disease severity, recognition of systemic complications, and identification of children at risk of progression to ESRD. The proposed developmental defect analysis, description of PUV sequence, clinical classification, and risk stratification approach are only the means to this end of segregating patient groups within the diagnostic spectrum.

Are pressure pop-offs beneficial to the bladder in boys with posterior urethral valves?

BACKGROUND

Pressure pop-offs, such as high-grade vesicoureteral reflux with renal dysplasia, have historically been considered beneficial for renal and bladder outcomes in boys with posterior urethral valves (PUV). Recent longer-term studies have called into question the beneficial effects of pop-offs on renal function.

OBJECTIVE

To evaluate how pop-offs affect bladder outcomes in boys with PUV.

STUDY DESIGN

At a single-center, the electronic medical records of boys with PUV who underwent valve ablation from 2000 to 2014 were retrospectively reviewed for bladder and continence outcomes. Patients were excluded due to presentation after one year of age, age at last follow-up <1 year, lack of urodynamic study (UDS), lack of voiding cystourethrogram, or concomitant prune belly syndrome. Between patients with and without pop-offs, the following outcomes were compared: prevalence of significant hydronephrosis (Society for Fetal Urology grade 3 or 4) prior to valve ablation and at last follow-up, nadir creatinine level, classification of initial UDS, type of medical and/or surgical interventions, dryness during the day and toilet-training status at last follow-up (among patients ≥4 years), and age at toilet-training. For patients with multiple UDS, initial and latest UDS were compared.

RESULTS

48 patients met inclusion criteria, of whom 31 (65%) had pop-offs and 17 (35%) did not. Median age at last follow-up was 5.9 years (range: 1.0-12.2 years). Patients with pop-offs were more likely to have unsafe initial UDS (26% vs. 12%, p = 0.15) but less likely to have high voiding pressures at their latest UDS (15% vs. 50%, p = 0.03). Patients with pop-offs were more likely to have used clean intermittent catheterization (26% vs. 0%, p = 0.04) and were less likely to be toilet-trained by age 4 (76% vs. 100%, p = 0.15) or dry during the day at last follow-up (56% vs. 92%, p = 0.06). Toilet-trained patients with pop-offs were toilet-trained by an earlier age than patients without pop-offs (3 vs 4 years, p = 0.04).

DISCUSSION

The results of the present retrospective study show that patients with pop-offs required more extensive interventions to achieve continence, and achieved continence and toilet-training less frequently than patients without pop-offs. Additionally, our results demonstrated that patients with pop-offs had worse bladder dynamics initially, which may suggest that pop-offs are a manifestation of more excessive pressure build-up prior to valve ablation.

CONCLUSIONS

Among boys with posterior urethral valves who present in the first year of life, pop-offs do not appear to impart significant benefit to bladder outcomes and may indicate more severe bladder dysfunction.

Posterior urethral valves: comparison of clinical outcomes between postnatal and antenatal cohorts

BACKGROUND

Posterior urethral valves (PUVs) constitute the most common infravesical urinary obstruction in boys and are often accompanied by severe consequences to the lower and upper urinary tract. Currently, about two-thirds of diagnosis of PUVs has been suspected by prenatal ultrasonography findings. The aim of this study was to compare long-term clinical outcomes in two groups of patients with PUVs, with antenatal vs. postnatal diagnosis.

STUDY DESIGN

This was a retrospective cohort study of 173 patients with PUVs systematically followed up in a tertiary center. Median follow-up time was 66.5 months (interquartile range [IQ], 11.4-147.9 months) for those patients who survived neonatal period. Seventy-nine (45.6%) patients were followed up for more than 5 years and 55 (32%) for more than 10 years. For analysis, the cohort was stratified into two groups according to the clinical presentation (prenatal vs. postnatal). The events of interest were urinary tract infection (UTI), surgical interventions, proteinuria, hypertension, chronic kidney disease (CKD), and death. Survival analyses were performed to evaluate time until occurrence of the events.

RESULTS

Sixty-two patients (35.8%) were diagnosed by fetal sonography. Patients of postnatal group presented a higher incidence rate of UTI episodes (6.5, 95% confidence interval [CI], 4.9-8.3) than antenatal group (1.2, 95% CI, 0.4-2.7) (P < 0.001). Thirty-six patients (21%) presented hypertension, and 77 (44.5%) had persistent mild proteinuria. There was no significant difference in the estimated incidence of hypertension (P = 0.28) and proteinuria (P = 0.78) between antenatal and postnatal groups. The cumulative incidence of CKD stage ≥3 was estimated to be about 37% at 10 years of age, and 56% at 18 years of age. By survival analysis, there was no significant difference in the estimated incidence of CKD stage ≥3 (log-rank = 0.32, P = 0.57) and CKD stage 5 (log-rank = 1.08, P = 0.28, Figure) between antenatal and postnatal groups. Of 173 patients included in the analysis, 13 (7.5%) died during follow-up with a median age of 2.6 months (IQ, 15 days-62 months). Survival analyses have not shown any significant difference in the estimated incidence of death between antenatal and postnatal groups (log-rank = 1.38, P = 0.24).

CONCLUSION

The study findings did not corroborate the initial hypothesis that the rates of renal function declining in patients with PUVs would be attenuated by an early diagnosis and intervention after antenatal diagnosis.

A clinical predictive model of chronic kidney disease in children with posterior urethral valves

BACKGROUND

Posterior urethral valves (PUVs) are associated with severe consequences to the urinary tract and are a common cause of chronic kidney disease (CKD). The aim of this study was to develop clinical predictive model of CKD in a cohort of patients with PUVs.

METHODS

In this retrospective cohort study, 173 patients with PUVs were systematically followed up at a single tertiary unit. The primary endpoint was CKD ≥ stage 3. Survival analyses were performed by Cox regression proportional hazard models with time-fixed and time-dependent covariables.

RESULTS

Mean follow-up time was 83 months (SD, 70 months). Sixty-five children (37.6%) developed CKD stage ≥ 3. After adjustment by the time-dependent Cox model, baseline creatinine, nadir creatinine, hypertension, and proteinuria remained as predictors of the endpoint. After adjustment by time-fixed model, three variables were predictors of CKD ≥ stage 3: baseline creatinine, nadir creatinine, and proteinuria. The prognostic risk score was divided into three categories: low-risk (69 children, 39.9%), medium-risk (45, 26%), and high-risk (59, 34.1%). The probability of CKD ≥ stage 3 at 10 years age was estimated as 6%, 40%, and 70% for patients assigned to the low-risk, medium-risk, and high-risk groups, respectively (P < 0.001). The main limitation was the preclusion of some relevant variables, especially bladder dysfunction, that might contribute to a more accurate prediction of renal outcome.

CONCLUSION

The model accurately predicts the risk of CKD in PUVs patients. This model could be clinically useful in applying timely intervention and in preventing the impairment of renal function.

Consensus on the Management of Posterior Urethral Valves from Antenatal Period to Puberty

The need for successful management of posterior urethral valves always captivates the minds of pediatric surgeons. Its success, however, depends on several factors ranging from prenatal preservation of upper tracts to postoperative pharmacological compliance. Regardless of measures available, some cases do not respond and progress to end stage. The management depends on several issues ranging from age and severity at presentation to long-term follow-up and prevention of secondary renal damage and managing valve bladder syndrome. This article is based on a consensus to the set of questionnaires, prepared by research section of Indian Association of Paediatric Surgeons and discussed by experienced pediatric surgeons based in different institutions in the country. Standard operating procedures for conducting a voiding cystourethrogram and cystoscopy were formulated. Age-wise contrast dosage was calculated for ready reference. Current evidence from literature was also reviewed and included to complete the topic.

Split-cuff nipple technique of ureteral reimplantation in children with thick-walled bladders due to posterior urethral valves

OBJECTIVE

To describe a novel technique of ureteral reimplantation in patients with thick-walled bladders, which addresses the technical challenges and high failure rates seen in this population.

METHODS

From 1997 to 2012, 45 megaureters were reimplanted in 26 children aged 2-11 years. Key surgical modifications included ureteral trough creation within the detrusor, formation of a distal ureteral split-cuff nipple, reliance on transureteroureterostomy (TUU) when the bladder would not support the reimplantation of 2 ureters, performance of psoas vesicopexy, and judicious utilization of ureteral stump augmentation in patients undergoing TUU. Follow-up ranged from 1 to 12 years.

RESULTS

Seven patients underwent unilateral and 4 underwent bilateral ureteral reimplantation; TUU was performed in 15. Psoas vesicopexy was performed in 22 patients. Voiding cystourethrography showed no reflux in all children who underwent vesicopexy. Reflux resolved in 6 of 8 bilaterally reimplanted ureters; 2 of 8 had improved reflux that later resolved with Deflux injection. No ureters obstructed. Hydronephrosis improved in 32 of 45 renal units and remained stable in 13. Seven patients continue to develop bacteriuria. Five have developed renal failure.

CONCLUSION

In our experience, a long ureteral trough combined with a split-cuff nipple technique for reimplanting megaureters into thick-walled bladders yields improved results over conventional submucosal tunneling, effectively eliminating or improving reflux and preventing obstruction. TUU and psoas vesicopexy proved useful adjuncts in creating adequate intravesical trough length. The risk for continued bacteriuria and renal failure due to limited renal reserve, however, remain notable in this group.

[Is there an outcome difference between posterior urethral valves diagnosed prenatally and postnatally at the time of antenatal screening?]

PURPOSE

Posterior urethral valves (PUV) diagnosed during childhood have classically been associated with a better outcome than antenatally diagnosed PUV. The aim of our study was to compare long-term outcome of these two patients' groups.

MATERIAL AND METHODS

We retrospectively reviewed the medical records of boys with PUV managed between 1990 and 2010. Patient demographics, clinical background, radiographic data (including prenatal ultrasonography data when available), renal and bladder functional outcomes, surgical procedures and urinary tract infections (UTI) were abstracted. Impaired renal function (IRF) was defined as glomerular filtration rate less than 90 mL/min/1.73 m(2) at last follow-up.

RESULTS

We identified 69 patients with confirmed PUV. Thirty-eight were diagnosed prenatally (group 1) at 30.5 weeks of gestation and 31 had a delayed diagnosis (group 2) at a median age of 6.31 years. At diagnosis, 20 patients in group 1 had renal insufficiency versus two in group 2 (P<0.05). At the end of mean follow-up of 7.2 ± 0.5 years, in group 1, 26.3% developed IRF versus 6.3% in group 2 (mean follow-up 2.3 years). Mean age at last follow-up was 7.3 years in group 1 versus 8.3 in group 2 (P>0.05). In group 1, 27% had voiding dysfunction versus 30% in group 2 (NS). In group 1, 35% had UTI during follow-up versus 10% (P=0.01).

CONCLUSION

During the follow-up, the patients with delayed diagnosis VUP have developed fewer complications related to the initial obstruction than the population who was detected antenatally and managed from the early hours of life. However, the rate of IRF and voiding disorders in our study, associated with the data of the literature, highlights the potential persistence and worsening of these conditions. That is why, whatever the age at diagnosis, VUP patients require a close monitoring.

The correlation between bladder volume wall index and the pattern of uroflowmetry/external sphincter electromyography in children with lower urinary tract malfunction

OBJECTIVE

To evaluate the relationship between bladder volume wall index (BVWI) and the pattern of uroflowmetry in children with lower urinary tract malfunction.

PATIENTS & METHODS

91 children aged 4-15 years with history of bladder dysfunction and 59 age/sex-matched healthy children with negative urine culture in previous month were enrolled. Uroflowmetry and kidney and bladder sonography were performed in all children. BVWI was measured by dividing maximum bladder volume index by mean bladder thickness. It was expressed as percentage by dividing calculated BVWI by expected BVWI, and values between 70% and 130% were presumed normal. Urodynamic study was done in symptomatic cases.

RESULTS

The bladder was thick (<70%) in 39 (28 cases, 11 controls) and thin (>130%) in 35 (18 cases, 17 controls) (P > 0.05). Uroflowmetry was abnormal in 82 (61 cases, 21 controls) (P < 0.05). Severe sphincter dyssynergia was detected in 47% of cases compared with 20% of controls (P < 0.05).There was no relationship between BVWI and uroflowmetry in cases or in controls (P > 0.05). The median post-void residual urine was not statistically different between the groups (20 vs 12.3 ml) (P > 0.05). When both bladder sonography and uroflowmetry were abnormal, they had an association with abnormal urodynamics (P < 0.05).

CONCLUSION

Among children with lower urinary tract dysfunction, the pattern of uroflowmetry could not be predicted from the BVWI, but in cases with combined abnormal bladder sonography and uroflowmetry results, there was a significant association with an abnormal urodynamic study.

Posterior urethral valves: long-term outcome

Posterior urethral valves represent the most common cause of bladder outlet obstruction in infancy that impairs renal and bladder function. Long-term outcome of patients with previous PUV is evaluated. Patients over 18 years of age, treated from 1982 to 1995 before the age of 3 years were considered. Previous surgery, renal function, bladder activity, urinary incontinence, and fertility/sexual activity were evaluated. Clinical interview, creatinine clearance, uroflowmetry with ultrasound post-void urine residue, and self-administered questionnaire were recorded. Out of 45 identified records, 24 patients (53.3%) accepted to be enrolled (age 18-34 years, mean 23 years). The mean follow-up was 19.5 years (16-30 years). Out of the 21 excluded patients, 20 did not reply to the clinical interview and 1 died at age of 6 years. All the 24 patients had early endoscopic section of PUV; nine also received transient ureterocutaneostomy or vesicostomy. Ureteroneocystostomy was performed in five patients and ureterocystoplasty with unilateral nephrectomy in two. At follow-up chronic renal failure was detected in 13 patients (54.1%) and 9 (37.5%) had arterial hypertension. End-stage renal disease developed in five patients (20.8%): three had successful renal transplantation and two were in dialysis. Lower urinary tract symptoms were present in seven patients (29.1%). No significant fertility deficit and sexual dysfunction were observed in 23 patients, while 1 patient was azoospermic. No paternity was reported so far. Long-term outcome of patients with previously treated PUV is mandatory. Kidney, bladder, and sexual functions should be monitored till adulthood to verify any modified behaviour.