Posterior urethral valves

Retrograde access seems to be the most frequently used procedure and has a very low rate of complications its main risk is post-procedural infection. The suprapubic approach is mainly used in neonates with posterior urethral valves and in children in whom catheter placement can be difficult or painful (urethral trauma, hypospadias, cloacal malformation). Suprapubic access requires preliminary bladder US. It can fail when the child voids during puncture. Leakage around the catheter in the prevesical space is common and benign. The risk of post-procedural infection decreases when using the supra-pubic approach. 

Indications for IRC include whenever renal reflux must be excluded in the toilet-trained older child (Figs. 1.3.1, 1.3.3, 1.3.4) ureteric dilatation, again in the toilet-trained older child older children with known bladder dysfunction (including posterior urethral valve) (Dinneen et al. 1994) and girls with recurrent UTI and normal ultrasound and Tc-99m DMSA scans, in whom the entire nephrourological system can be evaluated. 

Dinneen MD, Duffy PG, Lythgoe ME et al (1994) Mercapto-acetyltriglycine (MAG 3) renography and indirect radionuclide cystography in posterior urethral valves. Br J Urol 74 785-789... 

Rubinstein-Taybi syndrome Broad thumbs and toes, distinctive facial features, mental retardation, microcephaly, cryptorchism, small phallus Posterior urethral valves, abnormal bladder shape, absent or extra kidney, double renal pelvis Microdeletion 16p (about 25%), most often de novo (180849), further cases with mutations in CREBBP, EP300... 

Kaufmann-McKusick syndrome Hydrometrocolpos, transverse vaginal membrane, vaginal septum, postaxial polydactyly, cardiac anomalies, hypospadias Hydroureter, ureteral duplication, ectopic urethra, urogenital sinus, posterior urethral valves AR (236700), mutations in Bardet-Biedl type 6 BBS6 gene... 

An urinoma may complicate a UPJ obstruction. This type of complication may occur already in utero. It is more common with posterior urethral valves and acts like a protecting mechanism against obstruction (Avni et al. 1987 Genes and Vachon 1989). 

Cope RM, Snow BW (1991) Massive cystic ureteral diverticula in infancy. J Urol 146 575-577 CorralesJG, Elder JS (1996) Segmental multicystic kidney and ipsilateral duplication anomalies. J Urol 155 1398-1401 Cremin BJ (1986) A review of the US appearances of posterior urethral valves and ureteroceles. Pediatr Radiol 16 357-364... 

Posterior Urethral Valves in Neonates Imaging and Follow-Up 126... 

Posterior urethral valves consist of abnormal mucosal folds between the urethral wall and the distal end of the verumontanum. The classification established by Young at the beginning of the twentieth century appears questionable from an endoscopic perspective (Dewan et al. 1992). Young had identified three types of valves. Type I was described as a bicuspid valve radiating distally from the posterior edge of the verumontanum to the anterior aspect of the proximal membranous urethra. Type 1 valves are by... 

Fig. 6.3. Suprapubic voiding cystourethrography in a neonate with posterior urethral valves. A high-capacity heavily trabeculated bladder was opacified. Distended posterior urethra. Valves are ballooned by contrast medium ( sail in the wind sign)...

Continence is often a problem in children and adolescents with a history of obstructive posterior urethral valves. Urodynamic studies are sometimes helpful to evaluate vesical and sphincter functions. Growth of the prostate gland during puberty often yields transient or definite improvement (Pfister et al. 1996). 

In spite of extensive and precocious surgical treatment following prenatal diagnosis, many patients with a perinatal history of posterior urethral valves have subsequent deterioration of their renal function. Usually, if renal function quickly improves immediately after obstruction relief, then deterioration slowly develops in the following years (Drozdz et al. 1998). End-stage renal disease occurs in most patients with a history of severe obstruction during the first 20 years of life. 

Fig. 6.5. VCU in a neonate with prenatal diagnosis of megacystis and bilateral ureterohydronephrosis. Absence of posterior urethral valves. Megacystis megaureter association by aberrant micturition phenomenon...

There is a broad spectrum in posterior urethral valves. It should be remembered that some boys may have marked folds with no obstruction at all (Dewan and Goh 1995). This frequent radiological or endoscopic finding should be correlated with clinical complaints in order to ensure proper management of patients. 

Optimal neonatal management of boys with a prenatal diagnosis of posterior urethral valves necessitates excellent cooperation among obstetricians, pediatricians, surgeons and radiologists. Unfortunately, end-stage renal disease is still a frequent outcome. 

Fig. 6.7. a VCU in a 7-year-old boy with dysuria, showing extrinsic compression of the urethra due to abnormal sphincter contraction during micturition. This functional anomaly should not be mistaken for posterior urethral valves. Urody-namic studies favor dysfunctional voiding with bladder-sphincter dyscoordination during voiding. Biofeedback physiotherapy was carried out. Clinical outcome was favorable, b Follow-up VCU shows normalization of urethral anatomy during... 

Abbott JF, Levine D, Wapner R (1998) Posterior urethral valves inaccuracy of prenatal diagnosis. Fetal Diagn Ther 13 179-183... 

Reuter KL, Lebowitz RL (1985) Massive vesicoureteral reflux mimicking posterior urethral valves in a fetus. J Clin Ultrasound 13 584-587... 

Rittenberg MH, Hulbert WC, Snyder HM et al (1988) Protective factors in posterior urethral valves. J Urol 140 993-996... 

Whitaker RH, Sherwood T (1986) An improved hook for destroying posterior urethral valves. J Urol 135 531-532... 

Fig. 11.7. a Left grade IVUR and b posterior urethral valves seen during the voiding phase... 

Hulbert WC, Rosenberg HK, Cartwright PC et al (1992) The predictive value of US in evaluation of infants with posterior urethral valves. J Urol 148 122-124 Ismaili K, Avni FE, Piepz A et al (2006) VUR in children. 

Jungers P, Houilier P, Chauveau D et al (1996) Pregnancy in women with reflux nephropathy. Kidney Int 50 393-399 Kaefer M, Keating MA, Adams MC et al (1995) Posterior urethral valves, pressure pop-off and bladder function. J Urol 154 708-711... 

Bladder outlet obstruction (commonly posterior urethral valve)... 

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