Table 1.

Patients' demographics.

Number of patients	60 (49 males/11 females)
Pre-natal diagnostic	59 patients
Age at surgery	4.5 months (1–12 months)
Type of hydronephrosis (SFU)	22 grade III/38 grade IV
Weight at surgery	7.5 kg (5.2–9.5 kg)
Affected side	20 right kidney/41 left kidney
Associated anomalies	1 bilateral UPJO: left side operated at 8 month-old, right side at 3 year-old 1 horseshoe kidney 1 stenotic megaureter on the same side as UPJO 3 contralateral multicystic dysplastic kidneys
Complications before surgery	1 patient: atrial and ventricular septal defect and persistence of arterial duct, nephrostomy at 7 days of life because of severe obstruction; pyeloplasty performed 5 months later after the cardiac surgery 1 patient: pyonephrosis and sepsis had nephrostomy at 10 days of life; surgery was performed 4.5 months later 1 patient: upper pole perforation at 3 months of age required nephrostomy; surgery performed 15 days later
Mean operating time	140 min (80–240 min)
Conversion	0
Stent (Double J/percutaneous transanastomotic)	57 (29 Double J/28 percutaneous transanastomotic)
Suction drain	7