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 - Beyond the Abstract

Posterior urethral valves (PUV) are the most common cause of clinically significant urethral obstruction in boys with a significant proportion becoming symptomatic only after the perinatal period. Voiding cystourethrography (VCUG) often might fail to identify PUVs. Recent studies showed that detection rates for VCUG compared to endoscopy might be as low as 60%.

Especially after the perinatal period, there is a wide range of potential clinical symptoms rendering diagnosis challenging. Nevertheless, PUV is responsible for 17% of pediatric end-stage renal disease. Before damage of the kidneys occurs, boys show symptoms like febrile urinary tract infections (UTI), VUR, refractory bladder overactivity, daytime incontinence or they might show suggestive sonography findings. PUV represent a wide spectrum of urethral obstruction, initially described by Young et al. more than a century ago, who delineated three different forms of which mainly the so-called “Type I” PUV (originating at the seminal collicle with two leaflets unifying at a 12 o’clock position) and “Type III” PUV (more distally, ring-like appearance) are clinically accepted. Moreover, minor forms are reported in the literature with a varying degree of associated urodynamic obstruction. At present, it is unsure whether the several anatomical variants and shapes of PUV have a different impact on the development of modifications in the higher urinary tract.

This study evaluated the relationship between the radiological appearance of the posterior urethra, potential secondary radiological signs (bladder neck hypertrophy, bladder trabeculation and hypertrophy of the musculus interuretericus) and endoscopically documented PUV – considering also their extent and their anatomy. With cystoscopy as the current gold-standard method for diagnosis of PUV, this study is an approach of getting one step closer to a reliable assessment of the lower urinary tract in symptomatic boys through determining the present sensitivity of VCUG and identifying secondary radiological signs.

VCUG voiding image before endoscopy
Figure 1. VCUG voiding image before endoscopy and endoscopic image of the same patient. Note the regular calibre of the urethra on VCUG with no apparent sign of the significantly appearing Young Type I PUV found on endoscopy

Written by: Jonas Thüminger, MD, Resident Doctor for Children and Adolescent Surgery, University Clinic for Children and Adolescent Surgery, Salzburg State Clinics, Paracelsus Medical University, Salzburg, Austria, and Bernhard Haid, MD, Department of Urology, Sisters of Mercy Hospital Vienna, Vienna, Austria, Twitter: @bernhardhaid

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