ABSTRACT
With the widespread use of maternal ultrasound, the
incidence of hydronephrosis has increased significantly,
altering the practice of urology. A recent review of the trends
in the prenatal sonography use and subsequent urological
diagnoses in the United States demonstrated significant
increase in the overall ultrasound use over the last two
decades. Moreover, the mean number of ultrasounds per
pregnancy also increased significantly from 2.7 in 1998 to 4.2
in 2005.1 Pelvi-ureteric junction obstruction is the most
common cause of hydronephrosis detected antenatally.2,3 The
next most common cause of prenatally detected hydrone-
phrosis is obstruction at the uretero-vesical junction.2
Management of these patients after birth remains controver-
sial. The decision to intervene surgically has become more
complex because spontaneous resolution of antenatal and
neonatal upper urinary tract dilatations is being increasingly
recognized.2,46 The recognition and relief of significant
obstruction is important to prevent irreversible damage to
the kidneys.7 Differentiating urinary tract dilatations that are
significantly obstructive and require surgery from those that
represent mere anatomical variants with no implications for
renal function is not a simple task especially in newborns. It
has been shown that the changes in the function of the
involved kidney should be used as a measure of degree of
obstruction and indication for surgical intervention.4,5,710
