Primary megaureter in the neonate with prenatal or postnatal diagnosis.

Twenty-nine cases of primary megaureter diagnosed before the age of 3 months are grouped in this diagnostic and therapeutic study. Seventy-five per cent were discovered by antenatal sonography due to the presence of pelvicalyceal dilatation without localising precisely the position of obstruction, twenty-five per cent were detected by the occurrence of early urinary tract infection. Four patients were operated during the first few months. 2 diversions and 2 reimplantations. Fifteen including the 2 with early diversion were submitted to later reimplantation at the average age of 15 months. 12 patients were treated conservatively by antibiotics and regular supervision. The respective results of the operated and non-operated patients were evaluated comparing the initial dilatation and the last IVU using the classification of Beurton. Regardless of the marked initial dilatation, significant spontaneous regression or complete resolution were often seen during the first year of follow-up. Thus surgery should be deferred initially even for the severely dilated forms, except in a few critical cases where a diversion is indicated. Reimplantation should be deferred for some months unless deterioration is noted, or performed only after one year or 18 months if regression is insufficient, thus optimising operative conditions.