Gastrointestinal and Urinary
Procedure Guide
Indications
Nephrostomy Tube (PCN) - tube through the skin ending in the renal pelvis
Urinary obstruction, e.g., urosepsis, acute renal failure, intractable pain
Urinary diversion, e.g., hemorrhagic cystitis, ureteral injury, inflammatory/malignant fistula
Procedural access, e.g., stone removal, foreign body retrieval, tumor fulguration, ureteral embolization
Ureteroenteric fistula formation is known risk of urinary diversion for bladder CA in ~2.2% of cases
Primary surgical repair of ureteral injury/fistula fail in 35% (higher with cancer or XRT)
Diagnostic testing (rare today), e.g., antegrade pyelography, ureteral perfusion (Whitaker test)
Nephroureteral Tube/Stent (PCNU) - tube through skin often with pigtail in the renal pelvis but ending in the bladder. A “retrograde nephroureteral stent” instead uses the same tube as a nephrostomy tube for a patient with an ileal conduit but the tube passes through the urostomy ending in the renal pelvis.
Similar to above indications except urinary diversion. Classic teaching is that these should not be used for ileal conduits or neobladders as the bowel mucosa produces secretions that cause severe encrustation and clogging. However, PCNUs are still often used for treatment of anastomotic strictures and leaks after ileal conduit creation.
Provides access across the obstruction while undergoing treatment to resolve the obstruction, e.g., chemotherapy for a malignant obstruction or serial ureteroplasty. If the obstruction is unresolvable, it can serve as a bridge to ureteral stenting or destination (having the PCNU for life). Not all patients can tolerate have something in their bladder.
Ureteral Stent (JJ or “double J” stent) - tube from the renal pelvis to bladder with nothing external.
Most often placed by urology with cystoscopy retrograde but can also be placed antegrade.
Indications are the same to PCNUs and often prefered as first line for patient comfort (see alternatives below).
Ureteral Embolization
Palliative intervention often in the setting of malignancy with permanent pelvic fistulae to prevent constant leakage of urine and infections.
Require bilateral nephrostomy tubes for life
Contraindications
No absolute contraindication for initial placement if emergent but ideal to correct any coagulopathy
Stanford: Plt <50K, INR >1.7
SIR: Plt <50K, INR >1.9 OR Plt <30K, INR >2.5 with chronic liver disease
Efficacy and alternatives
Percutaneous nephrostomy access ~96-99% successful if dilated, ~85% if non-dilated, thresholds listed in the ACR-SIR-SPR Practice Parameter
Antegrade vs retrograde decompression for obstructive urosepsis has equivalent outcomes and risks in two RCTs (debunks common myth that retrograde with urology has increased bacteremia)
UTI/Obstruction + ureteral stents should exchange retrograde if remote last exchange. PCN better if suspected complication/progression after recent exchange
Malignant obstruction: antegrade > retrograde (98-100 vs 50%), particularly if distal obstruction
Transition to ureteral stent is ideal in terms of patient comfort but often requires established urologic care for exchanges and maturation of the tract.
Caveat: ureteral stents in women can be safely exchanged by IR with a retrograde approach using a snare
Should NOT use internalized ureteral stent for conduits as the mucous will obstruct the stent
Antegrade ureteral stent patency: 95% at 3 mo and 54% at 6 mo. However resonance metal stents can maintain patency up to 12 mo.
Pre-procedure care
Hold all antiplatelet and anticoagulant agents
Confirm with urology access needed if for a procedure, e.g., superior vs inferior pole calyx
Antibiotic prophylaxis recommended for new access (e.g. ceftriaxone)
procedures
Nephrostomy Tube
Prone or lateral decubitus positioning -> Pre-scan to plan approach (some say “ do more looking than sticking”). Good to stay more medial than lateral to avoid colon.
Access collection system
Many use a 22/21G echogenic needle (e.g. 22G Chiba or 21G thin wall). Others use a 19G needle if confident as this can accomodate an .035 wire (no transition).
Classic teaching is to target a posterolateral inferior pole calyx (Brodel’s avascular zone) unless different is needed for urology. Ideal to access calyx in single movement when entire needle and target in field of view because breathing will move target. Some use a needle guide while others do not.
Tricks for non-dilated systems:
Often help to give some IVFs while scanning and start of the case to help visualize a calyx to target.
Can use the “two stick technique” by sticking the renal pelvis with a 22G needle and injecting contrast and air (air will accumulate in posterior calices) and then target calyx with second stick (some recommend 18G). Renal pelvis can be targeted either via landmarks (often 2 cm lateral to L1/L2 transverse process) or targeting stone or stent if present.
Can also give IV contrast + 10 mg Lasix, but only have ~15 minutes of opacification after IV contrast.
Philips also has a system to use DynaCT to plan trajectory with dotted line to follow with fluoro.
(Optional) Contrast injection through access needle to confirm placement but can be dangerous if for obstructed urosepsis.
Advance Nitrix or similar microwire to maintain access, ideally into ureter.
Exchange needle for transition access catheter systems (e.g. MAK-NV, Greb set, Cook set) ideally into ureter.
Contrast injection to confirm placement
Exchange wire for Amplatz (or glide advantage if planning to cross obstruction with Kumpe or MPA).
Dilate tract being careful not too advance too far. Often place 8.5 Fr or 10.2 Fr initially.
Advance and form catheter.
Nephroureteral Tube/Stent
Same as above to gain access to the renal collection system. Some advocate for initially placing a nephrostomy tube and bringing the patient back to attempt crossing an obstruction once the tract has matured. Other suggest doing this in one visit, especially if initially access is not challenging.
Cross the obstruction and get access to the bladder
Some place a short sheath for stable access and supple, e.g., 8 Fr BriteTip
Common tools include glidewire + Kumpe, glidewire advantage, or just a Bentson allowing it to fold over to push past an obstruction.
For tougher obstructions, some use crossing catheter-sheath systems like with chronic venous obstructions (e.g. CXI and TriForce or NaviCross). Can also try sharp recanalization or RF wires like the venous system but more dangerous and less often used.
Measure the ureter length
PCNUs are sized by diameter (e.g. 10 vs 12 Fr) and the length between the pigtail in the renal pelvis and bladder (e.g. 10.2 Fr x 24 cm).
With a catheter down to the bladder (e.g. Kumpe), place a wire (e.g. Bentson) through the catheter so the tip is just within the bladder and place a clamp on the wire to mark this location. Pull the wire back so the tip is in the renal pelvis and place a second clamp on the wire to mark this location. Measure the distance between.
Some go up one size from the measurement as it’s better to be too long than too short (e.g. use a 24 cm PCNU when measuring 22 cm). However, if the PCNU is too long is can cause more bladder irritation.
Advance and form the PCNU - advance radioopaque marker of proximal pigtail into the proximal ureter. Removal the stiffener +/- wire. Twist the tube clockwise while gently pulling on the retention thread.
Ureteral Stent Extraction
Can be done fluoroscopically retrograde in women by snaring the distal pigtail and pulling out the stent through the shorter uretera.
For antegrade removal, place a 12-14 Fr peel-away sheath through nephrostomy access for 6 Fr ureteral stents or 14-16 Fr peel-away for 8 Fr ureteral stents.
Cutting a 45* bevel on the end of the peel-away can help for engaging the stent.
Three prong grasper or forceps used to grab the proximal pigtail and pull through the sheath.
A new stent or PCN can be placed if needed.
Whittaker Test (“Ureteral Stress Test”)
Place Foley as well as manometers in bladder and renal pelvis.
Record baseline pressures.
Infuse 20% contrast at 10 mL/min for 5 min and record pressures.
Increase infusion to 15-20 mL/min for 5 min and record pressures.
Repeat measurements with bladder distended.
Pressure differential between renal pelvis and bladder for flow rate of 10 mL/min <13 is normal, 14-22 mild/equivocal, 23-35 moderate obstruction, >35 severe obstruction.
Ureteroplasty
Many different approaches and “protocols” similar to benign biliary obstructions. Often involves serial plasty with larger balloons and tubes. People try a variety of things like prolonged inflation and cutting ballons. Things such as drug eluting balloons and cryoballoons have not been shown to be very helpful
Ureteral Embolization
Exchange PCN for an access sheath, e.g., 8Fr BriteTip
Advance a catheter into the distal ureter or just above the leak if ureteral leak.
Different people use different embolization material. Common approach is similar to gonadal vein embolization with “sandwich” of coils/plugs and glue, e.g., plug - glue - plug - glue - plug.
Replace the PCN
Complications
Major complications: septic shock (1-10%), hemorrhage (1-4%, higher with PCNL), vascular injury (0.1-1%), bowel transgression (0.2-0.5%), pleural complication (0.1-0.6%, higher if upper pole)
Minor complications: catheter malposition/dislodge (5%), pelvic perforation (4%), ileus (2%), fever (14%)
Post-procedure care & Follow Up
Most admit overnight for observation with fresh percutaneous access (some studies report up to 25% readmission rate for sepsis)
Monitor output - blood tinged urine is normal for a few days. Frank bloody output is not.
Flushing - some only have people flush if output very bloody or infected until urine clears. Other have people flush them daily. If the urine is clear, the flow of urine should keep the tubes patent.
Worsening or persistent bleeding -
Hold anticoagulation and antiplatelet agents and correct coagulopathies if present.
Can obtain CTA to assess for vascular injury and/or assess the tract by injecting contrast through a sheath over a wire and pulling back.
If performing angio for potential embolization, the PCN/PCNU may need to be removed over a wire for runs to unmask the lesion as the tube can tamponade and hide the issue.
Routine exchange every 2-3 months (2 months may be superior in terms of compliance and cost).
Can exchange ureteral stents in women under fluoroscopy. Easier than urologic approach according to some.
Long-term Issues:
Encrustation - only hydration found to be effective in preventing though many end up recommending flushing and more frequent exchanges
Decreased output - often due to dislodgement or clogging. Upon imaging to check positioning and assess flushing. Can sometime unclog with 1 mL syringe.
Dislodgment often requires exchange, urgent if completely dislodged as the percutaneous tract will close in a few days. Can try to recannulate with short Kumpe attached to contrast to try to opacify the tract.
Clogging - can try using a glidewire to get passed the blockage or the back end of a wire. Otherwise can try to Kumpe along side the existing tube or worst case, abandon the access and try to recannulate with the Kumpe.
Urinary tract infection - often does not require tube exchange unless the pathogen form biofilms