Ureteral stents are used to relieve benign or malignant obstruction of the ureter or as an adjunct to stone therapy. They are typically placed cystoscopically with the proximal coil in the renal pelvis and distal coil in the bladder. Complications can include malposition if too short or long, migration, urinary tract infection, inadequate relief of obstruction, encrustation, fracture, or erosion of the ureter. Careful positioning and timely removal are important to prevent complications.

1. Ureteral Stents
For the Diagnostic Radiologist
Jud Gash, MD
University of Tennessee, Knoxville
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3. The Typical Stent
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Indications
Placement
Stent
Normal Position
Common Symptoms

4. Indications
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Benign or Malignant obstruction relief
Adjunct to stone therapy
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Perioperative
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Obstruction
ESWL
Identification of the ureter
Management of Urine leaks
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After trauma, surgery or fistula

5. Placement
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Typically in OR
Cystoscopy (identify ureteral orifice)
+/- Retrograde pyelogram to outline upper tract
Placement of soft guidewire into upper tract
(kidney)
Place stent over guidewire (using pusher)
Remove guidwire

6. Stent Placement

7. Typical Stent
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Double J/Pigtail configuration
5-9 Fr
20-32 cm
Polyurethane

8. An aside – French Scale for Drads
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Charriere, Parisian surgical
instrument maker
French scale or gauge system
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Fr, F or Ga
Catheter size
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1 Fr = 1/3mm
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D(mm) = Fr/3
Ex. 30 fr catheter is (30/3)
– 10mm in diameter
Fr is close to circumference
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Sp. = External diameter
30 fr cath is about 30mm in
circumference
pi*d = C
Contrasts Needle gauge size,
where increasing gauge is
smaller

9. Normal Position
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Proximal coil in renal
pelvis
Distal coil in bladder
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In upper 1/4
Within 5cm of UVJ
Not beyond midline or
along bladder base
Proper position …
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Assures proper function
Reduces chance of
migration
Reduces irritative
symptoms
Proximal loop in
renal pelvis
Distal loop in
bladder, best in
upper 1/4

10. Common Symptoms
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Stent Irritation
Flank discomfort
 Bladder discomfort
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Pain
 Desire to void
 Incontinence
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Hematuria/Pyuria
Vesicoureteral Reflux

11. Complications/Issues
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Malposition (Too short or long/outside ureter)
Migration
UTI
Inadequate Relief of Obstruction
Encrustation
Fracture
Ureteral erosion/fistula
Forgotten Stent

12. Malposition
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Too short
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Doesn’t bridge the
obstruction/ureter
“fish reeling”
Too long
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Irritation
Urinary tract penetration
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Usually proximal
Urinoma; hematoma
Stent in optimal position

13. Malposition - Too Short

14. Malposition – Too Long

15. Update – Multi Length Stents
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Variable length
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Distal coil adjusts to
ureter length
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22-28 cm most
common
Shorter ureter – more
coil
Longer ureter – less
coil
Many fewer “too
short” or “too long”
stents

16. Malposition
Proximal
stent outside
kidney
Subtle indication of malposition with stent
distant to ureteral stone (after reposition)

17. Migration
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Prevented by proximal and distal “J” or loop
May occur due to peristalsis or short stent

18. Migration
Distal (more common)
and proximal migration

19. Urinary Tract Infection
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Not uncommon with stent
Causes
Stent placement (Abx before placement)
 Colonization
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20. Urinary tract infection
Patient with flank pain and fever 1
week following stent for distal stone

21. Inadequate Relief of Obstruction
or Stent Malfunction
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Relief of obstruction with ureteral stent is
complex
Intrinsic obstruction (ie stones - stent good)
 Extrinsic obstruction (ie malignant – less effective)
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Complex issues
Stent May become clogged/obstructed
Clinical Suggestion
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Flank pain (but often present anyway)
Renal insufficiency (insenstive)
Hydronephrosis (may persist from previous)

22. Inadequate Relief of Obstruction
or Stent Malfunction
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Imaging Diagnosis
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Doppler US – no ureteral jet and increasing hydro
No reflux at VCUG (or loopagram)

23. Patent Stent

24. Stent Obstruction with exchange

25. Encrustation
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All stents will accrue crystalline deposition
Hastened by UTI; lithogenic urine
 Increases with time (50% at 6-12 weeks)
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Particularly involves proximal and distal ends
Complications
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A main reason for stent exchange
Urinary tract injury and stent fracture at removal
Must be dealt with if severe prior to removal
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Lithotripsy, cystoscopy, etc.

26. Encrustation

27. Encrustation

28. Encrustation

29. Encrustation
Stone analysis revealed calcium oxalate 8% and calcium phosphate 92%
Kidney International (2007) 72, 899–900. doi:10.1038/sj.ki.5002429

30. Ureteral Erosion or Fistula
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Rarest and most feared
complication, especially
arterial
Usually in setting of
XRT and malignancy,
with indwelling stent
eroding into vessel
Hematuria, can be
massive
Arteriogram or CTA

31. Stent Fracture
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Urine is a hostile enviroment
Rare today
Increases with indwelling time
 Increases with encrustation
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32. Stent Fracture

33. Forgotten Stent

34. Forgotten Stent
IJCRI 201 2;3(4):45–47.
www.ijcasereportsandimages.com

35. Ureteral Stents – Wrap up
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Typical Stent
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Indications
Placement
Stent
Normal Position
Common Symptoms
Complications
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Malposition (Too short or long/outside ureter)
Migration
UTI
Inadequate relief or recurrent obstruction
Encrustation
Fracture
Ureteral erosion/fistula
Forgotten Stent