108 Neonatal Nephrostomy

Clinical Presentation

Prenatal ultrasonography demonstrated hydronephrosis and oligohydramnios. Immediate postnatal ultrasonography confirms the hydronephrosis and shows posterior urethral valves and a thickened bladder wall.

Figure 108A

Figure 108B

Radiologic Findings

Ultrasonography of the abdomen and pelvis demonstrates a markedly thickened bladder wall (Fig. 108A1), hydroureter, hydronephrosis (Fig. 108A2), and distended posterior urethra. Voiding cystourethrogram shows posterior urethral valves with thickened bladder and diverticulae (Fig. 108B).

Diagnosis

Posterior urethral valves with thickened bladder wall, hydroureter, and hydronephrosis. A percutaneous nephrostomy was requested.

Differential Diagnosis

Bilateral ureterovesical junction (UVJ) obstruction
Bilateral ureteropelvic junction (UPJ) obstruction

Discussion

Background

Percutaneous nephrostomy is a well-established procedure for the treatment of obstructive uropathy in the pediatric population. The neonatal population presents some additional difficulties, which are not seen in older children. Placing catheters in neonates may therefore be challenging even when the collecting systems are severely dilated.

Etiology

Congenital malformations are the predominant cause of urinary tract obstruction in the pediatric population. These include:

Ureteral malformations:
- UPJ narrowing or obstruction
- UVJ narrowing or obstruction
- Ureterocele
- Retrocaval ureter
Bladder outlet malformations:
- Bladder neck obstruction
- Ureterocele
Urethra malformations:
- Posterior urethral valves
- Anterior urethral valves
- Stricture
- Meatal stenosis
- Phimosis