[The hazards and complications of internal drainage of the upper urinary tract].

The causes, diagnosis, prevention and management of complications arising in insertion of internal ureteral stents have been analyzed basing on the results of 289 procedures in 272 patients. Dangers and complications related to drainage of upper urinary tracts (UUT) may be divided into technological (arising when inserting or removing the stent) and clinical (arising within the time of the stent location in the UUT). Technological complications emerged in 25 cases (8.7%). Of them, iatrogenic ureteral perforation occurred most frequently (9 cases, 3.1%). Clinical complications were registered in 41 patients (14.2%). Most common of them were: attacks of pyelonephritis due to vesicoureteral reflux and stent impassibility (19 and 9 patients, 6.6% and 3.1%, respectively). To ascertain the causes of the stent impassibility for urine, a complex of x-ray and ultrasound investigations was applied. The reflux is often provoked by the bladder drainage with urethral catheter. In the stent obstruction or concrement formation on it, the removal and changes of the stent were combined with extracorporeal or contact lithotripsy. Spontaneous distal migration of the stent (8 cases) necessitated its transurethral removal. Insertion of inner ureteral stents is rarely complicated by spontaneous migration of the drainage above the ureteral ostium (1 case) and by development of arterial-ureteral fistula (1 case). Thorough roentgenoendoscopical control over the stent insertion and staying in the UUT assists prevention and treatment of complications consequent to UUT internal drainage.