Endopyelotomy in horseshoe kidneys.

Three patients aged 23 to 43 years underwent endopyelotomy to treat stenoses of the ureteropelvic junction (UPJ) in horseshoe kidneys. One patient had failed open primary pyeloplasty and division of the isthmus previously. The other two patients had primary UPJ obstruction and small caliceal calculi associated with horseshoe kidneys. A hook-shaped cold knife was used to incise the ventromedial wall of the stenosis because of malrotation of UPJ in the horseshoe kidney. In two patients, a 14F endopyelotomy stent was left indwelling for 6 weeks. All three patients improved symptomatically, and two patients have shown persistent improvement of renal function radiographically for 52 and 34 months. These results suggest that endopyelotomy can be safely applied to UPJ obstruction in horseshoe kidneys with high efficacy.