Commentary

Knotted ureteral stent is a rare phenomenon. Only 13 cases have been reported so far.[1] Queck et al., were the first to report the formation of a knot in the mid portion of a stent in a lady.[2] Although they were unsure of the mechanism of how it formed, the probable explanation was that the patient had significant cystocele. According to them, displacement of the bladder with postural changes from the cystocele allowed the stent to buckle and ultimately to knot in the middle. Also, stent movement was likely involved since the proximal end had migrated down by the time the patient underwent lithotripsy for a pelviureteric junction stone. It is really interesting to think how the knot formed in this patient. The only probable explanation I could think of is that a loose knot formed in the proximal part of the stent in the pelvis during insertion and it came down to mid-ureter with peristalsis of the ureter. The learning pearls from this paper are individualization of stent length, always place the stent under fluoroscopy and be vigilant for this complication during stent removal to avoid ureteric injury.