Proximal urinary diversion in the management of posterior urethral valves: is it necessary?

In infants with posterior urethral valves in whom renal function fails to normalize following decompression of the lower urinary tract supravesical urinary diversion is customarily recommended for presumed concomitant ureterovesical junction obstruction. We determined the true incidence of fixed or permanent ureterovesical junction obstruction and the renal prognosis for infants treated with proximal urinary diversion.

We evaluated 26 patients with posterior urethral valves treated with supravesical urinary diversion. Mean gestational age at birth was 35 weeks (range 27 to 40). After initial decompression via an indwelling catheter for a median of 7 days (range 4 to 18) persistently high serum creatinine was present (median 2.5 mg./dl., range 1.9 to 3.5). One month after proximal urinary diversion median creatinine was 1.3 mg./dl. (range 0.5 to 2.8). At 1 year, median nadir creatinine was 1.0 mg./dl. (range 0.3 to 2.5). At reconstruction a Whitaker test in all 26 patients (52 renal units) demonstrated fixed ureterovesical junction obstruction in 2 units (4%).

Renal biopsy in 44 of the 52 renal units (85%) revealed renal dysplasia. At a median followup of 9 years (range 1 to 14) end stage renal disease developed in 11 patients (42%).

In neonates with posterior urethral valves who undergo proximal urinary diversion fixed ureterovesical junction obstruction is rare, renal biopsy invariably demonstrates areas of renal dysplasia and end stage renal disease frequently develops despite proximal diversion. These findings lead us to question the necessity of supravesical urinary diversion.