KNOT FORMATION IN A PATIENT WITH AN INDWELLING URETERAL STENT
BRIAN EISNER, HOWARD KIM, DIANNE SACCO
Department of Urology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
A patient treated for nephrolithiasis formed knots in 2 occasions, in 2 separate indwelling ureteral stents. This rare complication may make stent removal difficult. To our knowledge, this is the first case report of repeat knot formation in a single patient.
words: ureter; stent; complications; lithiasis
A rare complication of indwelling ureteral stents is knot-formation within the body or coiled portion of the ureteral stent. Several techniques for removal have been described, including simple traction, removal with guide wire assistance, ureteroscopy, and percutaneous removal (1-3). We report a case in which a patient formed knots in 2 separate stents.
82-year-old critically ill female with multiple medical problems, including
multiple sclerosis requiring tracheostomy, was treated for an 11x8 mm
left renal stone with a Cook Kwart Retro-Inject stent (6F x 22-32 cm)
in August, 2002. She was lost to follow up until July 2003 when she developed
Escherichia coli urosepsis. The stent was thickly encrusted requiring
2 shock wave lithotripsies and a ureteroscopy with laser lithotripsy to
facilitate removal. Examination revealed a knot in the proximal coiled
portion. Due to extensive manipulation during the procedure, a new Kwart
stent was placed with the plan to remove it within a short period of time.
formation is a rare complication of indwelling ureteral stents. We report
a patient who formed knots in 2 indwelling stents. Previous authors have
hypothesized that stent length, as well as coil configuration may be contributing
factors to stent knot formation (3). We surmise that the anatomy of the
patient’s renal pelvis in conjunction with the use of a Cook Kwart
Retro-Inject stent with multiple proximal coils increased the likelihood
of knot formation.
CONFLICT OF INTEREST