Is there a need for endoscopic evaluation in symptomatic boys with an unsuspicious urethra on VCUG? A consideration of secondary radiologic signs of posterior urethral valves

Seeking clinical consensus on risk assessment in anatomical infravesical obstruction of boys - A Delphi study

INTRODUCTION

Infravesical obstruction (IO) is a common urological condition in young boys. Patients may present with various signs and symptoms at different ages, with severity depending to a large extent on the degree of obstruction. Consensus concerning accurate and objective modalities to diagnose IO and to differentiate between an anatomical or functional cause is still lacking.

OBJECTIVE

This study aimed to reach consensus on the diagnostic determinants that are important to assess the likelihood of anatomical IO in boys and differentiate between an anatomical or functional cause.

STUDY DESIGN

A Delphi method was used to establish a list of diagnostic determinants that can be utilized in order to diagnose anatomical IO in boys. An international and interdisciplinary panel of experts was recruited to reach consensus using three sequential rounds of electronic questionnaires. Data were collected using the online survey platform Qualtrics. Rounds one and two were used to define diagnostic determinants. Round three was used to stratify key determinants according to age.

RESULTS

All rounds received a response rate of 100%. In round one, consensus was achieved on 44 of a total 79 items. In round two, consensus was achieved on 19 of a total 51 items. Round three identified a variation in key determinants per age group.

DISCUSSION

To create an effective tool for assessing IO in boys, key determinants identified in this study will need to be validated in a prospective clinical trial. Due to a large number of determinants and sections, this will not be a trivial task. In addition, since a Delphi study is based on expert opinion, any consensus achieved remains subjective. Diagnostic determinants identified in this study will need to be validated using prospective clinical data. Artificial Intelligence provides techniques for uncovering complex associations that cannot easily be reduced to equations. It may therefore play a pivotal role in the future development of robust IO risk assessment tools.

CONCLUSION

An international group of experts agreed that a risk assessment tool for IO in boys would be beneficial for both clinical practice and research purposes. Using a Delphi study methodology, consensus was reached on a set of diagnostic determinants that were considered important to assess the likelihood of IO and differentiate between an anatomical or functional cause. This study paves the way for further research on IO in boys. Eventually this could lead to an accurate and standardized assessment tool for IO.

Appearance of the bladder on initial voiding cystogram in boys with PUV and its relation to pre and postnatal findings

Introduction

Bladder profile in boys with Posterior Urethral Valves can be very varied with a spectrum going from high pressure, unstable, hypocompliant small bladders to hypercompliant, large acontractile bladders, with some being near-normal. Our question was whether appearance, specifically of the bladder, on initial VCUG was correlated to prenatal features and whether it could predict early postnatal outcome.

Method

We used a prospectively gathered database of boys with prenatally suspected PUV. We analyzed whether the appearance, specifically of the bladder, was related to date of prenatal diagnosis, presence of a megacystis on prenatal ultrasound, presence of vesico-ureteral reflux (VUR), presence of abnormal DMSA scan, nadir creatinine or presence of febrile urinary tract infection (fUTI) during the first two years of life.

Results

The database comprised 90 cystograms. 15% of bladders were judged normal/regular, 54 % were small/diverticular and 31% were large/diverticular. Bladder appearance was not associated with presence of prenatal megacystis, abnormal DMSA scan, VUR, nor rate of fUTI. The only significant associations were normal/regular bladder and early prenatal diagnosis (p = 0.04) and normal/regular bladder and elevated nadir creatinine (>75µmol/l) (p = 0.01).

Discussion

We believe that when focusing solely on the appearance of the bladder, excluding information about the urethra and presence of reflux, the cystogram alone is insufficient to inform on future bladder function. This could be used as an argument in favor of performing early urodynamics in this population.

Indirect signs of infravesical obstruction on voiding cystourethrography improve post-neonatal posterior urethral valves detection rate

OBJECTIVES

To identify the diagnostic performance of clinical and radiological signs (on voiding cystourethrography [VCUG]) to detect posterior urethral valves (PUV) in the post-neonatal period.

MATERIALS AND METHODS

One hundred eighteen males (median age = 0.8 years, range = 1 month-14 years, 48 toilet-trained) undergoing VCUG in a 2-year period were prospectively enrolled. Direct (dilated posterior urethra) and indirect (hypertrophied bladder neck, musculus interuretericus hypertrophy, and trabeculated appearance of the bladder wall) PUV signs on VCUG were assessed. Uroflowmetry was defined pathological by patterns suggesting infravesical obstruction.

RESULTS

Twenty-two patients with direct, 28 with indirect PUV signs on VCUG, and one with normal VCUG but persisting micturition symptoms with pathological uroflowmetry underwent urethrocystoscopy and in 43/51 a PUV diagnosis was made (n = 22, 51.2%, with direct PUV signs). In 8/28 patients with indirect signs, PUV were not confirmed. Among non-toilet-trained patients, none of the clinical signs/symptoms was associated with PUV while among toilet-trained patients only pathological uroflowmetry (odds ratio, OR = 4.0 [95% confidence interval:1.2-13.2; p = 0.02]) and pathological uroflowmetry with history of urinary tract infection (OR = infinity) were significantly associated with PUV. Significant associations with PUV of direct and indirect signs on VCUG were found both in toilet-trained and non-toilet trained patients. Direct PUV sign had 100% specificity and sensitivity while indirect PUV signs showed sensitivity = 58.1% and specificity = 89.3%. The absence of any radiological sign had a negative predictive value = 98.5%.

CONCLUSION

Only half of patients with endoscopy-confirmed PUV presents with direct sign of PUV on VCUG. Accounting for indirect PUV signs on VCUG and pathological uroflowmetry (in toilet-trained children) could improve the PUV detection rate.

CLINICAL RELEVANCE STATEMENT

Indirect radiological PUV signs should be valorized when interpreting VCUG to improve the PUV detection rate. The absence of any radiological PUV (direct and indirect) sign on VCUG excludes PUV with a very high negative predictive value.

KEY POINTS

• Worldwide agreement is that a non-dilated urethra on voiding cystourethrography excludes obstruction. • Half of patients with posterior urethral valves have non-dilated urethra on voiding cystourethrography. • Accounting for indirect signs of posterior urethral valves on voiding cystourethrography improves the diagnostic performance.

Thulium Laser for the Treatment of Posterior Urethral Valves in Infants

Objective: Thulium laser (ThL) has become popular in urology, because of its powerful action on tissue, achieving optimal ablation and hemostasis. Aim of our article was to evaluate efficacy of ThL in infants affected by posterior urethral valve (PUV) ablation. Patients and Methods: Clinical charts of 25 infants (age ≤12 months) who underwent PUV ablation were retrospectively reviewed. According to our protocol, all patients performed voiding cystourethrography and cystoscopy 6 to 8 months after initial treatment. Several factors, including age and weight at surgery, operative time, postoperative bleeding, catheterization period, postoperative urinary retention, retreatment for valve remnants, and stricture at follow-up, were evaluated. Preoperative, intraoperative, and postoperative data were analyzed. Results: Mean age at primary surgery was 4.5 months (5 days-10.5 months) and mean weight at primary surgery was 5.7 kg (2.5-10.3 kg). Mean operative time was 29.5 minutes (range 15-50 minutes). None of the patients experienced intraoperative and postoperative bleeding. In all cases, postoperative catheterization period was 1 day. Residual valves were found in 6 of 25 (24%) patients. No cases of urethral stricture were registered during follow-up (48.4 months, range: 11-95). Analyzing literature data using other techniques, complication rate of ThL PUV ablation seems lower than standard treatments (electrofulguration, cold knife) and comparable with those reported with other laser techniques. Conclusion: PUV ablation with ThL has proven to be feasible and safe in infants. Further studies are needed to define the real effectiveness of this laser technology in PUV ablation. Miniaturized instruments and ThL technology make early PUV treatment feasible also in low body weight newborns.

Early-in-Life Serum Aldosterone Levels Could Predict Surgery in Patients with Obstructive Congenital Anomalies of the Kidney and Urinary Tract: A Pilot Study

The aim of the study was to evaluate whether serum aldosterone levels or plasmatic renin activity (PRA) measured early in life (1-3 months) could predict a future surgical intervention for obstructive congenital anomalies of kidney and urinary tract (CAKUT). Twenty babies aged 1-3 months of life with suspected obstructive CAKUT were prospectively enrolled. The patients underwent a 2-year follow-up and were classified as patients needing or not needing surgery. In all of the enrolled patients, PRA and serum aldosterone levels were measured at 1-3 months of life and were evaluated as predictors of surgery by receiver-operating characteristic (ROC) curve analysis. Patients undergoing surgery during follow-up showed significantly higher levels of aldosterone at 1-3 months of life compared to those who did not require surgery (p = 0.006). The ROC curve analysis of the aldosterone for obstructive CAKUT needing surgery showed an area under the ROC curve of 0.88 (95%CI = 0.71-0.95; p = 0.001). The aldosterone cut-off of 100 ng/dL presented 100% sensitivity and 64.3% specificity and predicted surgery in 100% of cases. The PRA at 1-3 months of life was not a predictor of surgery. In conclusion, serum aldosterone levels at 1-3 months could predict the need for surgery during obstructive CAKUT follow-up.

Detection of bladder trabeculation by voiding cystourethrography and sonography: observations in boys with posterior urethral valves

Background

As trabeculated bladder wall is often referred to as a sign of chronically increased intravesical pressure, we investigated whether voiding cystourethrography (VCUG) or sonography reliably predicts bladder trabeculation on later urethrocystoscopy.

Methods

A total of 76 consecutive patients (2012–2017) with cystoscopically confirmed posterior urethral valves (PUV) and pre-endoscopy VCUG were included. Sonography data were available for 68 of these patients. Radiological findings were reassessed and compared with endoscopic findings using Fisher’s exact test and Spearman’s rank assessment.

Results

VCUG showed a sensitivity of 83.3% and a specificity of 30% in predicting trabeculation on a later urethrocystoscopy, with no significant difference in determining mild or severe forms (p=0.51). Sonography proved a sensitivity of 27.6% and a specificity of 70%, with no correlation between sonographic signs and trabeculation on cystoscopy (r=0.1311). In addition, vesicoureteral reflux had no significant influence as a possible pressure pop-off mechanism on the development of trabeculation in our group.

Conclusions

While VCUG predicts bladder trabeculation in children with PUV with limited reliability, sonography mostly fails to detect trabeculation. Therefore, such findings should only be used with utmost caution in relation to clinical decision-making.

Prolonged Indwelling Urethral Catheterization as Minimally Invasive Approach for Definitive Treatment of Posterior Urethral Valves in Unstable Premature Babies

Premature newborns with posterior urethral valves (PUV) may present with medical conditions taking priority over definitive surgical care. We encountered three of such cases who underwent initial bladder decompression via transurethral catheterization and waited 2-3 weeks until they were fit enough for voiding cysto-urethrography to confirm PUV. An unexpected good urinary flow and negligible residual urine volume were documented during micturition, suggestive of valve disruption induced by insertion and prolonged duration of indwelling urethral catheter drainage. Cystoscopy documented non-obstructing remnant leaflets. Non-operative treatment may be considered as a viable alternative therapeutic option for PUV in tiny babies facing prolonged intensive care unit stay.