Horseshoe kidney transplantation: an overview.

The horseshoe kidney is the most common anatomical renal variation. It represents a fusion anomaly, mainly at the lower poles, occurring between the 4th and 6th week of gestation. Horseshoe kidneys display a great variation in origin, number and size of the vasculature. Transplantation of these deviant kidneys can be done en bloc or they can be split into two halves and transplanted into two recipients, depending on the number of vessels and the anatomy of the urinary collecting system. A literature review reveals 31 case histories, published between 1975 and 1998. Of these 21 were transplanted into 38 recipients after division and ten were implanted en bloc. Nineteen grafts (41%) showed immediate function and 21 grafts (46%) showed delayed function. Thrombosis and acute rejection, leading to non-function was seen in six grafts (13%). The overall success rate was 87%) with a mean follow-up of 22 months. The results of horseshoe kidney transplantation are good. provided that attention is paid to certain technical details. Because of donor scarcity, horseshoe kidneys should be used for transplantation.