Midureteric knotted stent removed by percutaneous access!

Indwelling ureteric stents are commonly used in the management of upper urinary tract obstruction. A rare complication is the knotting of an indwelling ureteric stent at its proximal coiled end. We present a case of a mid ureteric knotted stent that put the kidney at risk. Stent was extracted successfully by Percutaneous method, after failed minimally invasive methods.

INTRODUCTION

Indwelling ureteral stents are commonly used in the management of upper urinary tract obstruction. A rare complication is the knotting of an indwelling ureteral stent at its proximal coiled end.[1-3] We present a case of a midureteric knotted stent that put the kidney at risk.

CASE REPORT

A 41-year-old male was evaluated for right loin pain and was found to have right renal calculus. He underwent right percutaneous nephrolithotomy (PCNL) with Double J stenting. Stone clearance as well as appropriate coiling of the proximal end of the stent in the renal pelvis was documented by fluoroscopy. The distal end was seen coiled in the bladder under direct cystoscopic examination. Postoperative period was uneventful. A month later, he came for follow-up and stent removal. Ultrasonography revealed moderate hydronephrosis and an X-ray KUB showed the DJ stent in situ with knotting at mid portion. Attempts at cystoscopic stent removal under local anesthesia and ureteroscopic removal under general anesthesia failed and hence percutaneous stent removal was planned. Superior caliceal puncture was made for better access into the renal pelvis and the upper ureter. Stent removal was accomplished easily with a 26 Fr Nephroscope, probably due to a dilated upper ureter. Postoperatively he recovered well.

DISCUSSION

Complications of indwelling stents include fragmentation, migration, encrustation, infection, and ureteric erosion or fistulae.[4] Although knotting of stents is a rare phenomenon, there are few reports describing knotted stents. It is interesting to speculate how the knot formed in that particular location. Most of these knots involve the proximal end of the stent near the coil, necessitating difficult and sometimes ingenious methods for extraction, including percutaneous approaches,[1] ureteroscopic methods,[2] and the use of special guide wires.[3] Recently, Holmium laser has been used with minimally invasive methods in the management of forgotten, severely encrusted stents.[5] Previous reports have attributed knot formation to excessive length of the stent with one end abutting the wall of a dilated renal pelvis and then passing through the open loop,[23] stent configuration (Double-J or multi-coil), and flexibility and[1-3] anatomical abnormalities such as cystocele and ileal conduits.[67] For selecting optimal stent length, Breau and Norman advocated direct measurement of ureteric length from the X-ray and postulated that the optimal stent-to-ureter length ratio is 1.04.[8] A variety of techniques to deal with knotted stents have been described. In this case, the stent was inserted to ensure drainage of the kidney in the immediate postoperative period. To our knowledge, this case represents the first instance in which a knot formed in the middle of the stent, in anatomically normal urinary tract. In conclusion, to prevent this unusual complication, variable or multi-length stents should probably be avoided and, when removing stents, we should be aware of the possibility of knotting, especially if there is significant resistance during withdrawal of the stent. Percutaneous access is a reliable and safe alternative for removal of such stents.