Spontaneous knotting of a pigtail ureteric stent in the ureter requiring percutaneous removal.

Insertion of a ureteric stent is a common procedure in urologic practice. Ureteric stenting may be performed for: ureteric obstruction, benign or malignant: to prevent ureteric obstruction from stone fragments after extracorporeal shockwave lithotripsy (ESWL); or to prevent leakage from the upper urinary tract. A case of spontaneous knotting of a ureteric stent in situ is reported. Although this complication has been reported previously it is rare.