[Congenital megaureter and its implications].

Divided into 9 sections, the difficult subject of megaureters is discussed. The classification comprises the primary and the secondary megaureter as well as the less well defined megacystis-megaureter syndrome. An embryopathy of the Wolffian duct and the ureteric buds is the underlying cause. Their main characteristics are obstruction and dysplasia. The primary megaureter develops supravesically. The secondary megaureter, as far as its cause is concerned, starts infravesically and is to be divided into two subgroups, depending on the time the embryopathy is developing. The megaureter, originating in the early embryonal phase is characterized by dysplasia and obstruction. The megaureter, originating in the late embryonal phase, presents obstruction only. The corresponding nephropathy shows obstructive, refluxive and dysplastic features. The causative distal obstruction ascends, its urodynamic reaction, however, descends in accordance with the rules of the pathophysiology of the smooth muscles of cavitary organs. Dilatation of the vesical bladder and the ureter are both prerequisite and symptom of muscular decompensation. The megacystis-megaureter syndrome is felt to be an extreme type of a simple reflux. The infravesical desobstruction is the most important step of the therapeutic strategy, followed by an antireflux ureterocystoneostomy with modellage. The indications are presented. Special types (the ectopic megaureter of a superior renal anlage, the prune-belly syndrome and the megaureter of the neurogenic bladder) are attributed to the classification as described above.