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Indications / Contraindications
Indications
- Relief of urinary obstruction (calculi, malignancy, stricture, retroperitoneal fibrosis)
- Infected obstructed collecting system (pyonephrosis) — URGENT
- Urinary diversion (ureteral injury, fistula, leak)
- Portal for endourologic procedures (nephrolithotomy, ureteral stent, rendezvous)
- Diagnostic (pressure studies, antegrade pyelography)
- Note: Hydronephrosis alone is NOT an indication — obstruction must be confirmed clinically + with imaging/labs
Contraindications
- Absolute: Uncorrectable coagulopathy (relative)
- Relative: INR <1.5 and platelets >50K generally acceptable
- Non-dilated system (increased technical difficulty, drops success to 82–96%)
- Horseshoe/ectopic/transplant kidney (modified approach required)
SIR Bleeding Risk
Category 2–3. INR <1.5, Plt >50K. Consider Category 3 if multiple passes expected or non-dilated system.
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Pre-Procedure Checklist
Review CT/US. Identify degree of hydronephrosis, stone burden, relevant anatomy (ribs, bowel, spleen/liver, pleura). Know if collecting system is dilated or non-dilated — impacts planning significantly.
Labs. CBC, BMP, coagulation panel (INR, PTT, Plt). Target INR <1.5, Plt >50K.
Antibiotics. Ceftriaxone 1g IV or gentamicin 1.5 mg/kg IV. Start 1h before procedure. Do NOT proceed without antibiotics — risk of sepsis is significant, especially with infected urine.
Consent. Hemorrhage (major ~1–4%), sepsis, pneumothorax (transpleural access risk), organ injury (liver, spleen, colon), failure to access, urinoma, pain.
NPO. Yes, minimum 4–6h (moderate sedation required).
Urine culture. Order if not done. Inform urology.
Positioning. Prone (gold standard). Prone oblique may be needed for transplant/ectopic kidneys.
Imaging review. Check for accessory spleens, horseshoe kidney, retrorenal bowel loops on prior CT.
Non-dilated system. If the collecting system is not dilated, give furosemide (Lasix) 20–40 mg IV 15–30 minutes before access to induce diuresis and distend the collecting system — markedly improves calyceal visualization under fluoroscopy.
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Relevant Anatomy
Access Route
- Target: Posterior lower or middle pole calyx — standard approach
- Approach below the 12th rib to avoid pneumothorax. Stay above 12th rib = transpleural (avoid unless necessary)
- Access site: posterior axillary line, below 12th rib
- Brödel's line: Relatively avascular zone between anterior and posterior renal segments, 1 cm posterior to the lateral convex border — target zone for calyceal access
- Upper pole: Reserved for stone procedures requiring angled access; higher pneumothorax risk (below 11th rib)
- Transplant kidney: Typically RLQ iliac fossa, anterior approach with US guidance
Danger Structures
- Pleura: Upper pole access risk — below 11th rib = transpleural; approach below 12th rib
- Renal vasculature: Main renal artery enters hilum; lower pole posterior calyx approach avoids central vessels. Pseudoaneurysm/AV fistula = most feared vascular complication
- Colon: Retrorenal colon in ~10% of patients — check CT before access
- Liver/Spleen: Right-sided and left-sided lateral approaches respectively
- Subcostal nerve/vessels: Approach above rib edge (inferior margin)
- Infundibulopelvic veins: Large intrarenal veins can be crossed with small needles safely
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Technique
Default RadCall approach · share your own below
Supplies
Ultrasound + sterile probe cover
C-arm fluoroscopy
ChloraPrep
Sterile drape
1% lidocaine
21G Chiba needle
0.018-inch guidewire
AccuStick introducer set
0.035-inch Amplatz super-stiff wire
8–10 Fr dilators
8 Fr locking pigtail nephrostomy catheter (Cope loop)
Nephrostomy drainage bag
Contrast + syringes
#11 scalpel
Steps
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Position + imaging survey
Patient prone. Survey with US to identify collecting system, assess degree of dilation, select target calyx (posterior lower pole preferred). Confirm the calyx is posterior (pointing toward you) — on US the posterior calyx opens wide with probe pressure.
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Prep + sterile setup
ChloraPrep prep, sterile drape. Mix dilute contrast (1:5 with saline) for fluoroscopic confirmation.
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Local anesthesia
1% lidocaine from skin to renal capsule. Note depth to calyx from skin.
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Needle access
Under real-time US guidance, advance 21G Chiba needle into target calyx. Confirm urine return. Aspirate urine + instill equivolume contrast to confirm position and delineate collecting system. Avoid overdistension — increases sepsis risk. Don't inject if you don't get urine — it will just obscure your window.
▶ US-guided posterior calyceal access
US-guided access: 18G needle targeting posterior lower-pole calyx — aim for the papilla, not the infundibulum, to establish a straight working channel.
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Wire placement
Advance 0.018-inch wire into collecting system via needle. Confirm under fluoroscopy — coil in renal pelvis.
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Tract dilation
AccuStick coaxial system → exchange to 0.035-inch wire → serial dilation to appropriate size (8–10 Fr for standard PCN). One-stick technique if using 18G access.
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Catheter placement
Advance 8–10 Fr locking pigtail nephrostomy over Amplatz wire. Coil in renal pelvis. Release locking mechanism. Confirm position with nephrostogram (gravity drainage) — contrast should flow from collecting system to ureter/bladder if unobstructed.
▶ Antegrade nephrostogram — final catheter position
Antegrade nephrostogram confirms catheter pigtail in renal pelvis with free drainage — assess for ureteral obstruction level before securing catheter.
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Secure + connect
Suture catheter to skin with 0-silk. Apply sterile dressing. Connect to drainage bag. Label bag with date/time.
Double-Stick Technique (Non-Dilated or Difficult Systems)
Use when the collecting system is minimally dilated and direct calyceal targeting is difficult. The first needle opacifies the system; the second needle accesses the target calyx under fluoroscopic guidance.
- 1First stick — opacification needle: Under US guidance, advance a 21G or 22G Chiba needle into the renal pelvis or any accessible calyx (precision not critical for this pass).
- 2Inject contrast: Slowly inject diluted iodinated contrast (1:1 with saline) through the first needle to opacify the collecting system under fluoroscopy. The pelvicalyceal anatomy is now visible.
- 3Identify target calyx: Under fluoroscopy, identify the posterior lower or middle pole calyx — look for the "end-on" calyx (appears as a circle, not a projection).
- 4Second stick — working needle: Under fluoroscopic guidance, advance an 18G or 21G access needle directly into the target calyx. The contrast outline makes targeting precise.
- 5Confirm access: Urine return or contrast aspiration from the working needle confirms calyceal entry. Proceed with standard wire and sheath placement.
- 6Remove first needle once the working wire is secured.
Pearl: The double-stick technique is also useful when the first access lands in the renal pelvis (suboptimal position) — keep that wire in place as a landmark, then make a second calyceal stick alongside it.
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Troubleshooting
Problem
No urine return after needle insertion
Likely cause: Poorly dilated system, needle tip not in calyx, or decompressed collecting system.
Next step: In poorly dilated systems — try IV contrast 50–75 mL and wait 3–5 min for contrast excretion. Under fluoroscopic guidance with contrast in calyces, use triangulation for targeting. Consider cone-beam CT guidance for non-dilated systems.
Problem
Excessive bleeding after access
Likely cause: Arterial injury (bright red, pulsatile) vs. venous/collecting system blood (darker, non-pulsatile).
Next step: Distinguish vascular from renal pelvis blood. Bright red, pulsatile = arterial injury — do NOT dilate, apply pressure. Evaluate with urgent CT angiography → embolization if pseudoaneurysm confirmed.
Problem
Difficult wire navigation
Likely cause: Wire not traversing into ureter or encountering stone/stricture.
Next step: Use hydrophilic angled wire (Glidewire) + angled catheter (Cobra, vertebral) to navigate into ureter. For crossing obstructions, balloon dilation after traversal.
Problem
Transpleural access confirmed on fluoroscopy
Likely cause: Upper pole access with pleural transgression — air or contrast seen in pleural space.
Next step: If confirmed, obtain chest radiograph. If pneumothorax >10% or symptomatic, chest tube required. Modify future access to subcostal approach below 12th rib.
Problem
Dislodged catheter during dilation
Likely cause: Loss of wire control during dilator exchanges.
Next step: Re-access with fresh Chiba needle. Maintain super-stiff wire control throughout all dilation steps — do not let go of the wire. Consider placing a second wire as safety before dilating.
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Complications
Immediate
- Hemorrhage (major ~1–4%) — most concerning; pseudoaneurysm/AV fistula → embolization
- Sepsis/bacteremia (1–10%) — most common cause of death; prophylactic antibiotics reduce risk
- Pneumothorax (1–4%) — if upper pole access; obtain CXR post-procedure
- Urine extravasation/urinoma — from inadvertent tract disruption
- Organ injury — liver, spleen, colon (retrorenal); rare but serious
Delayed
- Catheter occlusion/dislodgement — most common delayed issue; flush q8h with saline
- Pseudoaneurysm — delayed bleeding typically 2–4 weeks post-procedure; presents as gross hematuria
- Arteriovenous fistula — may close spontaneously; embolization if symptomatic
- Tract infection — skin/tract cellulitis; local wound care ± antibiotics
- Post-obstructive diuresis — after relief of chronic obstruction; monitor electrolytes
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Post-Procedure Care
Monitoring
- Vitals q30 min × 2h post-procedure
- Monitor drainage output and color. Initial hematuria common (pinkish-red) — should clear in 24–48h. Frank blood = concerning
- Nephrostogram at 48–72h to confirm position and document drainage
- Drain flushing: 5–10 mL sterile saline q8h to maintain patency
- Urine culture from initial aspirate
Follow-up & Instructions
- Urology follow-up for definitive management planning
- Catheter exchange: every 3 months (Cope loop) to prevent encrustation
- Post-obstructive diuresis: Monitor electrolytes closely post-procedure. Diuresis >200 mL/h = replace 50–75% of output with IV saline
- Patient/family education: drain care, dressing changes, signs of dislodgement or infection
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Critical Pearls
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Lower pole posterior calyx is your friend. Angled back toward you on US, below 12th rib, away from major vessels. This is the default target — deviate from it only if the clinical indication requires otherwise.
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ALWAYS give antibiotics before procedure. Pyonephrosis → sepsis can happen intraoperatively. Do not start the case without prophylaxis in place.
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Never overdistend the collecting system with contrast. Aspirate urine volume = instill contrast volume only. Overfilling infected urine pyelovenous backflow → bacteremia → sepsis.
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Maintain a super-stiff wire throughout all dilation steps. Losing wire access = starting over. Keep firm control of the Amplatz wire at all times and confirm position fluoroscopically before each dilator exchange.
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Retrorenal colon in 10% of patients. Check CT before starting — especially left-sided nephrostomy. If retrorenal colon is present, access requires modification.
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Non-dilated system — have a plan. Consider IV contrast excretion technique (give 75 mL IV contrast, wait 5 min for calyceal opacification) or cone-beam CT guidance. Don't fight a non-dilated system blindly.
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Post-obstructive diuresis: After relieving chronic obstruction, monitor for diuresis >200 mL/h. Replace 50–75% of output with IV normal saline. Obtain BMP q6h until diuresis stabilizes.
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Catheter Management
Catheter Types & Exchange
- 8–10 Fr pigtail: Standard PCN; exchange every 3 months
- 14–18 Fr: For empyema/thick collections
- Large-bore: Complex stone access tracts
- Exchange earlier if: Occlusion, dislodgement, persistent infection, or encrustation
Output Norms
- Expected: 500–1500 mL/day after obstruction relief — track 24h output
- Urine leak around catheter: Check position + patency; flush. If dislodged, cover with sterile gauze and call IR immediately
- Catheter occlusion: Flush with 10 mL sterile saline gently. Do NOT force. If still occluded, exchange under fluoroscopy
- Minimal output: Rule out dislodgement, catheter kinking, or bladder outlet obstruction
Post-Obstructive Diuresis Protocol
| Urine Output Rate | Action | Additional Steps |
|---|---|---|
| <200 mL/h | Routine monitoring | BMP once at 6h |
| 200–500 mL/h | Replace 50–75% of output with IV normal saline | BMP q6h, strict I/O |
| >500 mL/h | Aggressive IVF replacement — 75% of hourly output | BMP q4–6h, consider ICU monitoring |
| Any rate with rising Cr or electrolyte abnormality | Nephrology consult | Adjust IVF composition based on lytes |
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References & Resources
Primary sources · Key data · Related procedures
Key Guidelines
- SIR practice standard for PCN
- EAU guidelines on urological infections
Primary References
- Dyer RB, Regan JD, Kavanagh PV, Khatod EG, Chen MY, Zagoria RJ. Percutaneous nephrostomy with extensions of the technique: step by step. Radiographics. 2002;22(3):503–525.
- Ramchandani P, Cardella JF, Grassi CJ, et al; Society of Interventional Radiology Standards of Practice Committee. Quality improvement guidelines for percutaneous nephrostomy. J Vasc Interv Radiol. 2003;14(9 Pt 2):S277–S281.
- Dagli M, Ramchandani P. Percutaneous nephrostomy: technical aspects and indications. Semin Intervent Radiol. 2011;28(4):424–437.