What is the recommended surgical procedure for removing a large kidney stone after stent placement?

Surgical Management of Large Kidney Stones After Stent Placement

For large kidney stones (>20 mm), percutaneous nephrolithotomy (PCNL) is the recommended first-line surgical procedure, regardless of prior stent placement. 1

Primary Treatment Recommendation

PCNL should be offered as the definitive treatment for large renal stones because it provides:

• Stone-free rates of 74-87% for complex stones 1
• Superior efficacy compared to other modalities when stone burden exceeds 20 mm 1
• Direct visualization and removal of all stone fragments under direct vision 1

The presence of a pre-existing ureteral stent does not change this recommendation—PCNL remains the optimal approach for large stone burden. 1

PCNL Technical Approach

Access and Stone Removal

• Upper pole access typically provides optimal visualization of the entire collecting system for staghorn or large stones 1
• Multiple access tracts may be required (10-50% of cases) depending on collecting system complexity 1
• Flexible nephroscopy must be routinely performed during PCNL to access fragments that migrate to areas inaccessible by rigid nephroscope 1
• Holmium:YAG laser or pneumatic/ultrasonic lithotripsy should be used for stone fragmentation 1

Irrigation and Drainage

• Normal saline irrigation is mandatory to prevent hemolysis, hyponatremia, and electrolyte abnormalities 1
• Nephrostomy tube placement after uncomplicated PCNL is optional, though complex stones may require drainage for 24-48 hours 1
• Tubeless PCNL with ureteral stent alone is acceptable if there is no active hemorrhage and no anticipated need for repeat percutaneous access 1

Alternative Approaches When PCNL is Contraindicated

If PCNL cannot be performed due to:

• Uncorrectable coagulopathy or anticoagulation 1
• Anatomic derangements preventing proper positioning 1
• Severe contractures or flexion deformities 1

Then staged ureteroscopy (URS) is the viable alternative, though it:

• Requires multiple procedures for large stone volumes 1
• May not render patients completely stone-free 1
• Has lower stone-free rates (81% for 10-20 mm stones) compared to PCNL (87%) 1

Combination Therapy Considerations

PCNL combined with shock wave lithotripsy (SWL) may be used for complex stones, but:

• PCNL should be performed first to remove bulk stone burden 1
• The final procedure should be percutaneous nephroscopy (second-look PCNL), not SWL, as fragment passage after SWL is incomplete 1
• This approach is used less frequently due to improvements in flexible nephroscopy and laser technology 1

Critical Safety Considerations

Infection Management

• If purulent urine is encountered during any procedure, abort immediately, establish drainage (stent or nephrostomy), culture the urine, and continue broad-spectrum antibiotics 1
• For septic patients with obstructing stones, urgent decompression with percutaneous nephrostomy or ureteral stent is mandatory before definitive stone treatment 1

Antibiotic Prophylaxis

• Administer antimicrobial prophylaxis within 60 minutes of PCNL based on prior urine cultures and local antibiogram 1
• Single dose covering gram-positive and gram-negative uropathogens is recommended 1

Expected Outcomes and Follow-up

• Average 1.3 PCNL procedures are needed for complete stone clearance 1
• Transfusion rates range from 14-24% 1
• Hospital stay typically 1-5 days depending on complexity and need for secondary procedures 1
• Return to normal activities within 1-2 weeks after drainage tube removal 1
• Stone material should be sent for analysis to guide metabolic evaluation 1

When Open/Laparoscopic Surgery May Be Considered

Open, laparoscopic, or robotic surgery should not be first-line therapy except in rare cases of: 1

• Anatomic abnormalities requiring concomitant reconstruction (UPJ obstruction, ureteral stricture) 1
• Failed endoscopic approaches with large or complex stones 1