===Removal of previous catheter===
*Check the position of the previous catheter tip with a few ml of iodinated contrast, preferably in two projections such as a lateral and a more frontal one.* <br>[[#Troubleshooting|Troubleshooting: Catheter in calyx]]
*Loosen any pigtail
*Insert a guidewire (such as Amplatz) into the renal pelvis or proximal ureter.* <br>[[#Troubleshooting|Troubleshooting: Cannot advance guidewire]]*Remove the previous catheter while keeping the guidewire in place.* <br>[[#Troubleshooting|Troubleshooting: Catheter stuck]]
===Insertion of new catheter===