DUPLICATION OF THE URINARY COLLECTING SYS TEM WITH OBSTRUCTION

Duplication of the urinary collecting system (DUCS) is characterized b y the presence of two ureters draining the same kidney. There are usua lly no symptoms. Obstruction occurs only in the event of abnormal uret eral termination, of which each type leads to specific manifestations. Sixty-nine pediatric patients with DUCS were treated between 1988 and 1993. Most were under one year of age, 23 had reflux into the lower p ole ureter, 18 had ectopic ureteral insertion and 26 had a ureterocele involving the upper pole ureter (two also had obstruction of the lowe r ureteropelvic junction). The diagnosis was prenatal in 40 cases. The treatment of reflux and ectopic ureteral insertion proved simple; ure terovesical reimplantation was done in 16 cases, uretero-ureteral anas tomosis in four, and heminephrectomy in 21, and no reoperations were n eeded. In contrast, the ureteroceles raised challenging therapeutic pr oblems: of the nine patients treated by heminephrectomy, four required a second surgical procedure, and of the 14 patients treated by remova l of the ureterocele with or without heminephrectomy and/or ureteral r eimplantation, four developed complications requiring surgical treatme nt. Endoscopic treatment was done in 13 patients and allowed preservat ion of the upper pole in seven; however, surgery was required subseque ntly in ten of these 13 patients. Renal lesions were often severe: of the 73 renal poles involved (six patients had bilateral DUCS), 39 were nonfunctional and 21 were dysplastic. These findings, together with t he fact that most of the patients were neonates, indicates that renal lesions in patients with DUCS are mainly the result of malformation.