Background: A horseshoe kidney is the most common renal fusion anomaly and occurs
in 0.2% to 0.3% of the population. Horseshoe kidneys are fused by the formation of
an isthmus between the lower poles of the left and right kidneys during development.
The insertion of the ureter in the renal pelvis is displaced super-laterally, probably as the
result of incomplete renal rotation, and is associated with a significant rate of ureteropelvic
junction (UPJ) obstruction.
Case Presentation: We report a patient with single kidney at right side with obstruction in
upper ureter. Before the surgery our plan was transureteroureterostomy according to
failure of previous surgeries, dismembered pyeloplasty and ureterocalicostomy, but after
mobilizing the proximal ureter we noticed that transureteroureterostomy was impossible
because of short fibrotic ureter. Other choices such as Boari flap technique with psoas
hitch is impossible because of small fibrotic bladder, so we decided to use appendix as
Conclusions: According to our experience and previous studies, we can use appendix as a
ureter substitution in refractory proximal and middle ureter stenosis, but in our case we
anatomized proximal ureter to appendix instead of anastomosis of pelvic to appendix.