Outcome analysis of vesicoamniotic shunting in a comprehensive population

Prenatal detection of obstructive uropathy is used widely and vesicoamniotic shunting is the accepted procedure in well-defined cases. We present outcomes of vesicoamniotic shunting in a consecutive series from a coordinated prenatal-postnatal treatment program.

From 1989 to 1998 bladder obstruction was identified in 89 fetuses at a multidisciplinary prenatal high risk clinic. Prenatal intervention was considered in cases of bilateral hydronephrosis associated with evidence of bladder outlet obstruction and oligohydramnios.

Indications for prenatal shunting were present in 12 patients (13%), and 9 underwent vesicoamniotic shunt insertion between weeks 20 and 28 of gestation. None of the prenatal procedures was associated with preterm labor, chorioamnionitis or urine chemistry values greater than cutoff threshold on bladder tap. Shunts were extruded from 2 fetuses, which required sequential insertion. After prenatal intervention 1 patient elected pregnancy termination and the others proceeded to term. Two neonates died at birth, and 6 survived. The underlying urological diagnosis was posterior urethral valves in 4 newborns, urethral atresia in 1, and prune belly variant and urethral atresia in 1. Of the patients 3 had relatively normal renal function, 2 had severe renal insufficiency and 1 had mild renal impairment. Five newborns are voiding freely and 1 underwent bladder reconstruction and is on intermittent catheterization. None of the patients had pulmonary problems at last followup.

Although vesicoamniotic shunting is effective in reversing oligohydramnios, its ability to achieve sustainable good renal function in infancy is variable. No specific prenatal parameters were effective in predicting eventual good renal function. Pulmonary function cannot be assured with restoration of amniotic fluid.