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Ureteral StentsUreteral StentsFor the Diagnostic RadiologistFor the Diagnostic Radiologist
Jud Gash, MDJud Gash, MD University of Tennessee, KnoxvilleUniversity of Tennessee, Knoxville
The Typical StentThe Typical Stent
IndicationsIndications PlacementPlacement StentStent Normal PositionNormal Position Common SymptomsCommon Symptoms
IndicationsIndications
Benign or Malignant obstruction reliefBenign or Malignant obstruction relief Adjunct to stone therapyAdjunct to stone therapy
ObstructionObstruction ESWLESWL
PerioperativePerioperative Identification of the ureterIdentification of the ureter
Management of Urine leaksManagement of Urine leaks After trauma, surgery or fistulaAfter trauma, surgery or fistula
PlacementPlacement
Typically in ORTypically in OR Cystoscopy (identify ureteral orifice)Cystoscopy (identify ureteral orifice) +/- Retrograde pyelogram to outline upper tract+/- Retrograde pyelogram to outline upper tract Placement of soft guidewire into upper tract Placement of soft guidewire into upper tract
(kidney)(kidney) Place stent over guidewire (using pusher)Place stent over guidewire (using pusher) Remove guidwireRemove guidwire
Stent PlacementStent Placement
Typical StentTypical Stent
Double J/Pigtail configurationDouble J/Pigtail configuration 5-9 Fr5-9 Fr 20-32 cm20-32 cm PolyurethanePolyurethane
An aside – French Scale for DradsAn aside – French Scale for Drads Charriere, Parisian surgical Charriere, Parisian surgical
instrument makerinstrument maker French scale or gauge systemFrench scale or gauge system
Fr, F or GaFr, F or Ga Catheter sizeCatheter size
Sp. = External diameterSp. = External diameter 1 Fr = 1/3mm1 Fr = 1/3mm
D(mm) = Fr/3D(mm) = Fr/3 Ex. 30 fr catheter is (30/3) Ex. 30 fr catheter is (30/3)
– 10mm in diameter– 10mm in diameter Fr is close to circumferenceFr is close to circumference
30 fr cath is about 30mm in 30 fr cath is about 30mm in circumferencecircumference
pi*d = Cpi*d = C Contrasts Needle gauge size, Contrasts Needle gauge size,
where increasing gauge is where increasing gauge is smallersmaller
Normal PositionNormal Position Proximal coil in renal Proximal coil in renal
pelvispelvis Distal coil in bladder Distal coil in bladder
In upper 1/4In upper 1/4 Within 5cm of UVJWithin 5cm of UVJ Not beyond midline or Not beyond midline or
along bladder basealong bladder base Proper position …Proper position …
Assures proper functionAssures proper function Reduces chance of Reduces chance of
migrationmigration Reduces irritative Reduces irritative
symptomssymptoms
Proximal loop in renal pelvis
Distal loop in bladder, best in
upper 1/4
Common SymptomsCommon Symptoms
Stent IrritationStent Irritation Flank discomfortFlank discomfort Bladder discomfortBladder discomfort
PainPain Desire to voidDesire to void IncontinenceIncontinence
Hematuria/PyuriaHematuria/Pyuria Vesicoureteral RefluxVesicoureteral Reflux
Complications/IssuesComplications/Issues
Malposition (Too short or long/outside ureter)Malposition (Too short or long/outside ureter) MigrationMigration UTIUTI Inadequate Relief of ObstructionInadequate Relief of Obstruction EncrustationEncrustation FractureFracture Ureteral erosion/fistulaUreteral erosion/fistula Forgotten StentForgotten Stent
MalpositionMalposition Too shortToo short
Doesn’Doesn’t bridge the t bridge the obstruction/ureterobstruction/ureter
““fish reeling”fish reeling” Too longToo long
IrritationIrritation Urinary tract penetrationUrinary tract penetration
Usually proximalUsually proximal Urinoma; hematomaUrinoma; hematoma
Stent in optimal position
Malposition - Too Short Malposition - Too Short
Malposition – Too LongMalposition – Too Long
Update – Multi Length StentsUpdate – Multi Length Stents Variable length Variable length
22-28 cm most 22-28 cm most commoncommon
Distal coil adjusts to Distal coil adjusts to ureter lengthureter length Shorter ureter – more Shorter ureter – more
coilcoil Longer ureter – less Longer ureter – less
coilcoil Many fewer Many fewer “too “too
short” or “too long” short” or “too long” stentsstents
MalpositionMalposition
Proximal stent outside kidney
Subtle indication of malposition with stent distant to ureteral stone (after reposition)
MigrationMigration
Prevented by proximal and distal Prevented by proximal and distal “J” or loop“J” or loop May occur due to peristalsis or short stentMay occur due to peristalsis or short stent
MigrationMigration
Distal (more common) and proximal migration
Urinary Tract InfectionUrinary Tract Infection
Not uncommon with stentNot uncommon with stent CausesCauses
Stent placement (Abx before placement)Stent placement (Abx before placement) ColonizationColonization
Urinary tract infectionUrinary tract infection
Patient with flank pain and fever 1 week following stent for distal stone
Inadequate Relief of Obstruction Inadequate Relief of Obstruction or Stent Malfunctionor Stent Malfunction
Relief of obstruction with ureteral stent is Relief of obstruction with ureteral stent is complexcomplex Intrinsic obstruction (ie stones - stent good)Intrinsic obstruction (ie stones - stent good) Extrinsic obstruction (ie malignant – less effective)Extrinsic obstruction (ie malignant – less effective)
Complex issuesComplex issues
Stent May become clogged/obstructedStent May become clogged/obstructed Clinical SuggestionClinical Suggestion
Flank pain (but often present anyway)Flank pain (but often present anyway) Renal insufficiency (insenstive)Renal insufficiency (insenstive) Hydronephrosis (may persist from previous)Hydronephrosis (may persist from previous)
Inadequate Relief of Obstruction Inadequate Relief of Obstruction or Stent Malfunctionor Stent Malfunction
Imaging DiagnosisImaging Diagnosis Doppler US – no ureteral jet and increasing hydroDoppler US – no ureteral jet and increasing hydro No reflux at VCUG (or loopagram)No reflux at VCUG (or loopagram)
Patent StentPatent Stent
Stent Obstruction with exchangeStent Obstruction with exchange
EncrustationEncrustation
All stents will accrue crystalline depositionAll stents will accrue crystalline deposition Hastened by UTI; lithogenic urineHastened by UTI; lithogenic urine Increases with time (50% at 6-12 weeks)Increases with time (50% at 6-12 weeks)
A main reason for stent exchangeA main reason for stent exchange
Particularly involves proximal and distal endsParticularly involves proximal and distal ends ComplicationsComplications
Urinary tract injury and stent fracture at removalUrinary tract injury and stent fracture at removal Must be dealt with if severe prior to removalMust be dealt with if severe prior to removal
Lithotripsy, cystoscopy, etc.Lithotripsy, cystoscopy, etc.
EncrustationEncrustation
EncrustationEncrustation
EncrustationEncrustation
EncrustationEncrustation
Stone analysis revealed calcium oxalate 8% and calcium phosphate 92%
Kidney International (2007) 72, 899–900. doi:10.1038/sj.ki.5002429
Ureteral Erosion or FistulaUreteral Erosion or Fistula
Rarest and most feared Rarest and most feared complication, especially complication, especially arterialarterial
Usually in setting of Usually in setting of XRT and malignancy, XRT and malignancy, with indwelling stent with indwelling stent eroding into vesseleroding into vessel
Hematuria, can be Hematuria, can be massivemassive
Arteriogram or CTAArteriogram or CTA
Stent FractureStent Fracture
Urine is a hostile enviromentUrine is a hostile enviroment Rare todayRare today
Increases with indwelling timeIncreases with indwelling time Increases with encrustationIncreases with encrustation
Stent FractureStent Fracture
Forgotten StentForgotten Stent
Forgotten StentForgotten Stent
IJCRI 201 2;3(4):45–47.www.ijcasereportsandimages.com
Ureteral Stents – Wrap upUreteral Stents – Wrap up Typical StentTypical Stent
IndicationsIndications PlacementPlacement StentStent Normal PositionNormal Position Common SymptomsCommon Symptoms
ComplicationsComplications Malposition (Too short or long/outside ureter)Malposition (Too short or long/outside ureter) MigrationMigration UTIUTI Inadequate relief or recurrent obstructionInadequate relief or recurrent obstruction EncrustationEncrustation FractureFracture Ureteral erosion/fistulaUreteral erosion/fistula Forgotten StentForgotten Stent