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internal ureteral stents are used to maintain ureteral patency in the management of various benign and malignant forms of ureteral obstruction ( 1 ) .
today , placement of a double - j ureteral stent ( djus ) is a widely used treatment for palliative decompression by diversion of urine and prevention of uremia in patients with malignant ureteral obstruction .
however , djus is associated with some adverse effects such as encrustation , stone formation , pain , infection , reflux , bladder irritation and decreased ureteral peristalsis ( 2 , 3 ) . therefore
, these stents have to be exchanged or removed within 4 - 6 months of placement and often cause significant patient discomfort and decrease quality of life . in an attempt to improve existing djus ,
ureteral stent exchange is usually performed under both fluoroscopic and cystoscopic guidance . in previous studies ,
ureteral stent exchange using a snare loop or foreign body forceps has been performed under fluoroscopic guidance ( 6 - 8 ) .
herein , we have reported our experiences with retrograde placement of metallic ureteral stent via urethra under fluoroscopic guidance in two patients .
this case report was approved by our institutional review board . an informed consent to participate in this study
a 56-year - old woman was admitted with left hydronephrosis on computed tomography ( ct ) .
she had undergone an operation ( total gastrectomy , distal pancreatectomy and splenectomy ) for gastric cancer one month ago .
the patient had undergone percutaneous nephrostomy ( pcn ) and placement of djus was performed electively via pcn tract after urine was clear .
after one month , the patient complained dysuria and frequency and wanted to place metallic ureteral stent instead of djus .
patient was placed in a supine position and povidone - iodine was used locally as aseptic agent .
analgesia ( fentanyl citrate ) was routinely administrated intravenously ( iv ) , immediately before the procedure without conscious sedation .
after topical urethral anesthesia with lidocaine gel , insertion of 10f vascular sheath was performed . under fluoroscopic guidance ( axiom artis dta , siemens , erlangen , germany ) , a snare wire of 25mm - in - diameter ( amplatz gooseneck snare , coviden , plymouth , mn , usa ) was introduced through the sheath into the bladder lumen .
after capture and partial extraction of the previously inserted djus ( figure 1 a ) , insertion of the wire ( radiofocus , terumo , tokyo , japan ) through djus into left renal pelvis and removal of the djus were performed .
tubogram obtained after insertion of the wire showed diffuse stricture of proximal to mid ureter with mild dilatation of pelvicalyceal system of the left kidney .
after exchange of wire to stiff one ( radiofocus , terumo ) and dilatation using 6 mm - 10 cm balloon ( mustang balloon , boston scientific , natick , ma , usa ) with hand injection pressure , insertion of two 6mm-12 cm metallic ureter stents ( uventa , taewoong medical , gimpo , korea ) were performed with sparing of distal ureter ( figure 1 b ) .
final tubogram using 5f kumpe catheter ( cook , bloomington , in , usa ) showed good passage of contrast media ( xenetix 300 , guerbet , roissy cdg cedex , france ) into urinary bladder through partially expanded stent ( figure 1 c ) .
the ureteral stent had been patent for six months and creatinine level remained normal on follow - up . a 54-year - old woman with gastric cancer
the patient had undergone pcn and placement of djus was performed . during six months after placement of djus , the patient continuously complained dysuria , frequency and discomfort and wanted to place metallic ureteral stent instead of djus .
we placed 6 mm - 12 cm metallic ureter stent ( uveta stent ) via transurethral route as abovementioned method ( figure 2 ) .
a 56-year - old woman was admitted with left hydronephrosis on computed tomography ( ct ) .
she had undergone an operation ( total gastrectomy , distal pancreatectomy and splenectomy ) for gastric cancer one month ago .
the patient had undergone percutaneous nephrostomy ( pcn ) and placement of djus was performed electively via pcn tract after urine was clear .
after one month , the patient complained dysuria and frequency and wanted to place metallic ureteral stent instead of djus .
patient was placed in a supine position and povidone - iodine was used locally as aseptic agent .
analgesia ( fentanyl citrate ) was routinely administrated intravenously ( iv ) , immediately before the procedure without conscious sedation .
after topical urethral anesthesia with lidocaine gel , insertion of 10f vascular sheath was performed . under fluoroscopic guidance ( axiom artis dta , siemens , erlangen , germany ) , a snare wire of 25mm - in - diameter ( amplatz gooseneck snare , coviden , plymouth , mn , usa ) was introduced through the sheath into the bladder lumen .
after capture and partial extraction of the previously inserted djus ( figure 1 a ) , insertion of the wire ( radiofocus , terumo , tokyo , japan ) through djus into left renal pelvis and removal of the djus were performed .
tubogram obtained after insertion of the wire showed diffuse stricture of proximal to mid ureter with mild dilatation of pelvicalyceal system of the left kidney .
after exchange of wire to stiff one ( radiofocus , terumo ) and dilatation using 6 mm - 10 cm balloon ( mustang balloon , boston scientific , natick , ma , usa ) with hand injection pressure , insertion of two 6mm-12 cm metallic ureter stents ( uventa , taewoong medical , gimpo , korea ) were performed with sparing of distal ureter ( figure 1 b ) .
final tubogram using 5f kumpe catheter ( cook , bloomington , in , usa ) showed good passage of contrast media ( xenetix 300 , guerbet , roissy cdg cedex , france ) into urinary bladder through partially expanded stent ( figure 1 c ) .
the ureteral stent had been patent for six months and creatinine level remained normal on follow - up .
a 54-year - old woman with gastric cancer was admitted with right hydronephrosis on follow - up ct .
the patient had undergone pcn and placement of djus was performed . during six months after placement of djus , the patient continuously complained dysuria , frequency and discomfort and wanted to place metallic ureteral stent instead of djus .
we placed 6 mm - 12 cm metallic ureter stent ( uveta stent ) via transurethral route as abovementioned method ( figure 2 ) .
however , it evokes significant discomfort and decreases the quality of life because of the externally placed catheter .
although djus is more comfortable for patient than pcn , there are several flaws that prevent its widespread use .
moreover , complications such as early obstruction , migration and fracture can occur easily after placement ( 4 ) .
metallic stent does not need change or removal periodically and decreases symptoms related to djus such as pain and urinary symptoms .
therefore , using metallic stent instead of djus leads to higher quality of life and longer ureteral patency ( 5 ) .
antegrade approaches for removal and exchange of ureteral stents via pcn tract have been described ( 9 ) .
however , these are technically more difficult , are much more painful and psychologically demanding for patients than retrograde approaches , also require placement of a large catheter through a percutaneous tract with all the attendant risks and complications of that procedure ( 10 ) . therefore , this procedure was used in limited cases of failure of retrograde transurethral approach . the standard technique used to exchange a djus
is performed under cystoscopy ( 6 , 7 ) . however , because of the rigidity and larger diameter of a cystoscope , some patients need deep sedation or general or epidural anesthesia for pain management during the procedure ( 10 ) .
fluoroscopic transurethral exchange of djus has been described with various techniques in the literature ( 6 - 8 , 10 ) . the simple snare technique using a goose - neck snare can be performed easily in most cases . the same as exchange of djus , fluoroscopy guided placement of metallic stent by transurethral approach was possible in patients with previously inserted djus . as above described cases , exchange of ureteral metallic stent was easy and safe by the same method of djus exchange . as compared with antegrade approach , this technique has advantage that there is no need to make a new pcn tract . generally , retrograde exchange of ureteral stents under fluoroscopic guidance is safe and easy ( 6 - 8 , 10 ) .
it can be performed under topical anesthesia by radiologists after a short training period and the success rate is high with a low incidence of complications among women ( 7 ) . however , these cases were female , which could be a weak point .
retrograde approach may be more difficult in men , because men have a longer urethral tract and the possibility of benign prostatic hyperplasia making the advancement of the sheath difficult . in conclusion , in patients with djus and symptoms who want to change djus to metallic stent , fluoroscopic guidance of transurethral placement of ureteral metallic stent is a good option instead of cystoscopic procedure or percutaneous procedure through pcn tract .
ureteral stent exchange is usually performed under both fluoroscopic and cystoscopic guidance . 
 we experienced two cases with retrograde placement of metallic ureteral stent via urethra under fluoroscopic guidance . 
 when patients with double - j ureteral stent ( djus)have symptom and want to change djus to metallic stent , fluoroscopic guided transurethral placement of ureteral metallic stent is a good option as alternative of cystoscopic procedure or percutaneous procedure through percutaneous nephrostomy tract .