[Causes of proximal atresia of the ureter in congenital hydronephrosis].

The proximal ureter atresia as a cause of a congenital hydronephrosis with functioning normal kidney is to a certain extent unknown. The histological elaboration of an uretero-pelvic resection preparation of a 7-year-old boy after Anderson-Hynes-plasty showed the transition of a stenosis of the ureter passage into a ureter atresia. Cause of the development of a proximal ureter atresia are secondary changes of the structure in the ureteropelvic segment due to the disturbed urodynamics in stenosis of the ureter passage. The possibilities of the genesis of atresia are discussed and it is referred to the clinical picture of the disease.