Systematic antenatal ultrasonography has significantly altered the con
ditions of diagnosis of megaureters. Pediatric urologists are now conf
ronted with a large group of neonates with asymptomatic megaureter. Fu
rthermore, reports of spontaneous resolution of primary megaureter wit
hout reflux have become common. We were confronted with 59 renal units
in 48 neonates. We postulated that primary megaureter represented a s
ignificant obstructive uropathy when the kidney exhibited stasis and l
arge pelvic and caliceal dilatations. So, 35 ureters were operated on
initially. The other 24 cases were managed conservatively but among th
ese patients, 11 ureters were operated on secondarily 7-29 months afte
r the diagnosis because they were unchanged [6] or worsened [5]. 13 ur
eters are currently without treatment: 7 total regressions and 6 incom
plete regressions with persistent mild pelvic dilatation. The results
of reimplantation, early or delayed, have been excellent (1 postoperat
ive necrosis reoperated, 1 secondary reimplantation, 2 persistent mild
dilatations). Relief of obstruction without reflux was obtained in 36
/39 long-term follow-up cases (92%). There is a disagreement about the
relative merits of various modalities in the assessment of ureteral o
bstruction and impairment of renal function. Therefore, we chose to us
e essentially intravenous pyelography (IVP) and to operate initially w
hen there was a delayed appearance of the contrast agent, a massive di
latation and delayed drainage from the ureter into the bladder. This a
ttitude is open to question but no more illogical than waiting for imp
airment of renal function to decide on surgery.