Percutaneous nephrolithotomy (PCNL)

How PCNL is done

Under general anaesthetic, a small puncture is made through the skin of the flank into the target calyx of the kidney, guided by x-ray and ultrasound. The tract is gently dilated over a wire, and a working sheath is placed directly into the kidney. Stones are then broken up and removed piece by piece using combinations of:

• Ultrasonic lithotripsy - sound-wave energy combined with suction to fragment and aspirate stone.
• Pneumatic lithotripsy - a miniature jackhammer-type probe.
• Holmium laser - for residual fragments in positions awkward for rigid probes.³

Flexible ureteroscopy is often used through the same tract, or from below, to check every calyx and retrieve fragments that cannot be reached from the main tract. At the end of the procedure, a small drainage tube (nephrostomy) or a ureteric stent may be left temporarily.

Mini-PCNL

For selected stones, a smaller-calibre approach - mini-PCNL - uses a tract of 14-22 French instead of the standard 24-30 French. This reduces the renal injury and bleeding risk and may allow tubeless (stent-only) drainage, at the cost of slightly longer operating time for larger stones.²

Who PCNL is recommended for

• Kidney stones greater than 2 cm.^{1, 2}
• Stag-horn stones and complex branched stones.
• Lower-pole kidney stones greater than 10 mm, where PCNL gives higher clearance than ESWL or flexible ureteroscopy.²
• Stones that have failed previous ESWL or flexible ureteroscopy.
• Anatomical variants (horseshoe kidney, pelvic kidney) where endoscopic access is limited.

Outcomes

For stones > 2 cm, PCNL achieves a single-session stone-free rate of around 75-90% in contemporary series, far higher than either ESWL or flexible ureteroscopy for the same stone burden.^{1, 2} A small proportion of patients need a second PCNL, or a second-stage ureteroscopy, to clear every fragment.

Risks to discuss

Because the procedure involves a working channel through the kidney, PCNL carries specific risks that are weighed carefully against the alternatives:

• Bleeding - the most important specific risk; transfusion is occasionally required and, very rarely, embolisation of a bleeding vessel in radiology.
• Infection and sepsis - minimised by ensuring a clear urine culture pre-operatively and by targeted antibiotic prophylaxis.
• Urinary leak after tube removal - usually self-limiting.
• Injury to adjacent structures - lung (pleura) for upper-pole punctures, colon, spleen or liver - all uncommon.
• Residual stone requiring a second procedure.

Admission, recovery and return to activity

1. Pre-admission

   Urine culture, full blood count, kidney function and clotting. Anticoagulants are usually stopped in advance under cardiology guidance.

2. The procedure

   General anaesthetic. Typically 1.5-3 hours depending on stone size and complexity. Patients receive broad-spectrum antibiotic prophylaxis.

3. In hospital

   A one- to two-night stay is typical.⁴ Any nephrostomy tube is assessed the following day and usually removed before discharge. A ureteric stent, if placed, stays in for 1-2 weeks.

4. Early recovery

   Oral analgesia for 7-14 days. A small amount of pink urine is common. Most patients return to desk work within 1-2 weeks.

5. Return to activity

   Heavy lifting and strenuous exercise are avoided for around 4 weeks.

6. Follow-up imaging

   CT KUB or ultrasound at 4-12 weeks to confirm stone clearance. A second procedure is arranged if clinically significant residual stone remains.

Patient information brochures

Percutaneous (keyhole) removal of kidney stones (PCNL) PDF - BAUS patient brochure Percutaneous nephrostomy PDF - BAUS patient brochure Endoscopic litholapaxy PDF - BAUS patient brochure

Related pages

References

1. Skolarikos A, et al. EAU Guidelines on Urolithiasis. 2025.
2. Pearle MS, et al. Surgical Management of Kidney and Ureteral Stones: AUA Guideline (2026).
3. Kim HJ, Ghani KR. Which is the best laser for lithotripsy? Holmium laser. European Urology Open Science. 2022.
4. Johns Hopkins Medicine. Percutaneous nephrolithotomy (PCNL).