Exchange of an occluded nephroureteral stent by using a snare.

Percutaneous retrograde nephroureteral stent exchange may be complicated by catheter occlusion with calcareous debris. When a guide wire cannot be passed through the catheter, a snare may be advanced over the stent into the renal pelvis, permitting withdrawal of the occluded stent while maintaining access for placement of a new stent. This procedure was performed successfully in a 73-year-old man.