Introduction. The duplex kidney is one of the most common congenital abnormalities of the urinary tract, and various surgical procedures exist for the management of this condition. Depending on the surgeon preferences, patients with duplex kidney may undergo heminephrectomy with ureterectomy using open or laparoscopic approach, uretero-cysto-anastomosis of the ectopic ureter or two ureters in a single block. Recently, there have been reports of inter-ureter anastomoses. Here we report our multicenter experience in open and laparoscopic uretero-ureteral anastomosis (UUA).
The study aimed to improve the treatment results in children with urodynamic dysfunction due to the duplicated upper urinary tract.
Materials and methods. We retrospectively analyzed medical records of 64 children treated from 2007 to 2017. There were 22 (32.8%) boys and 43 (67.2%) girls with mean age 40.2 months at the time of surgery. All of them had duplex kidneys, including 27 (42.2%) right-sided and 37 (57.8%) left-sided. Of them, 15 (23.4%) children underwent distal UUA (DUAA), and 49 (76.6%) had proximal UUA (PUUA).
Results. After surgery, acute pyelonephritis occurred in three patients. In the early postoperative period, a prolonged urinary leakage from surgical site drainage was observed in three (6.1%) patients after laparoscopic PUUA. One (4.2%) child developed a stumpitis. Thus, complications occurred in 7 (10.9%) children; one of them (1.6%) needed additional treatment.
Conclusion. Distal and proximal UUA is a safe and effective surgical treatment for urinary outflow disorders in patients with the duplicated upper urinary tract, minimizing the risk of the duplex kidney dysfunction.

Keywords: duplicated upper urinary tract, uretero-ureteral anastomosis, duplex kidney, laparoscopy, children