Urethral Valves

Introduction Posterior urethral valves (PUVs) are a rare malformation in the subcollicular region of the male urethra. They cause varying obstructions of the lower urinary tract. The resulting secondary pathological conditions extend from mild—in part, clinically unmanifested—urinary dysfunctions to severe, bilateral changes in the upper urinary tract and associated renal failure. The literature puts the incidence between 1 in 5,000 and 1 in 8,000 male births. No clear hereditary association has been demonstrated, although a certain hereditary aspect is probable.1 An incidence in identical twins and, very rarely, a familial cluster have been described in the literature. There are usually no concomitant malformations outside the genitourinary tract. The modern literature on PUVs had its origin in the publications of Young et al. in 1919.2 Their differentiation of three types of valves is a subject of debate, but is still used regularly. From the perspective of paediatric surgery, type I and type III urethral valves are of particular significance. In these, the flow of urine is opposed either by mucous membrane folds projecting “backdrop-like” into the lumen in lithotomy position from 7 to 5 o’clock directly below the seminal colliculus (type I), or by an aperture-like stenosis (type III). A more recent description of the valve structures with the designation COPUM (congenital obstructive posterior urethral membrane) subsumes Young et al.’s type I and II valves into one class. Endoscopic observations agree well with this classification, when it is taken together with the different structure known as “Cobb’s collar”, which is clearly distal of the seminal colliculus.3