What is the treatment for large kidney stones using Percutaneous Nephrolithotomy (PCNL)?

Percutaneous Nephrolithotomy (PCNL) for Large Kidney Stones

For patients with large kidney stones (total renal stone burden >20 mm), PCNL should be offered as first-line therapy due to its significantly higher stone-free rates compared to other treatment modalities. 1, 2

Stone Size-Based Treatment Algorithm

• For renal stones ≤20 mm (non-lower pole), either shock wave lithotripsy (SWL) or ureteroscopy (URS) may be offered as first-line treatment 1, 2
• For renal stones >20 mm, PCNL is the preferred treatment with stone-free rates significantly higher (94%) than URS (75%) 1
• For lower pole stones ≤10 mm, either SWL or URS can be offered 1
• For lower pole stones >10 mm, SWL should not be offered as first-line therapy due to poor success rates (58% for 10-20 mm stones, declining to 10% for >20 mm stones) 1

PCNL Technique and Considerations

Pre-Procedure Assessment

• Evaluate for contraindications including anticoagulation/antiplatelet therapy that cannot be discontinued, contractures, or anatomic derangements that would prevent proper positioning 1
• Obtain appropriate imaging to assess stone burden and anatomy, with additional imaging for complex urinary tract anatomy 1
• Administer antimicrobial prophylaxis based on prior urine culture results and local antibiogram 1

Procedural Technique

• Use normal saline irrigation during PCNL to prevent electrolyte abnormalities (strong recommendation) 1, 2
• Employ a safety guidewire for most endoscopic procedures 1
• Perform flexible nephroscopy as a routine part of standard PCNL to access stone fragments that migrate to areas inaccessible by rigid nephroscope 1, 2, 3
• Consider tubeless PCNL (no nephrostomy tube) in uncomplicated cases where the patient is presumed stone-free 1, 2

Special Situations

• If purulent urine is encountered during the procedure, abort stone removal, establish drainage, continue antibiotics, and obtain urine culture 1
• For patients with obstructing stones and suspected infection, urgently drain the collecting system with a stent or nephrostomy tube before definitive stone treatment 1
• In patients not considered candidates for PCNL, staged URS may be offered as an alternative 1
• For patients with negligible kidney function in the affected kidney, nephrectomy may be considered 1

Outcomes and Complications

• PCNL offers the highest stone-free rates among all minimally invasive treatment options for large stones 4, 3
• The success rate of PCNL is less dependent on stone composition, density, and location compared to other modalities 1
• While PCNL has higher stone-free rates, it carries higher risks of bleeding and other complications compared to SWL or URS 2
• Recent advancements in PCNL techniques include miniaturized access tracts (mini-PCNL, ultra-mini PCNL) which may reduce morbidity while maintaining efficacy 5, 6

Post-Procedure Management

• Send stone material for analysis to guide prevention strategies 1
• When residual fragments are present, offer patients endoscopic procedures to render them stone-free, especially if infection stones are suspected 1
• Consider alpha-blockers and anti-muscarinic therapy to reduce stent discomfort if a ureteral stent is placed 1

Common Pitfalls and Caveats

• Avoid using non-isotonic irrigation solutions which can increase risk of hemolysis, hyponatremia, and heart failure 1
• Do not attempt PCNL without proper equipment and fluoroscopy access, as these are critical for ensuring complete stone removal 7
• Avoid tubeless PCNL if there is active hemorrhage or if another percutaneous procedure will likely be needed to remove residual stones 1
• Do not offer SWL as first-line therapy for stones >20 mm as it has significantly reduced stone-free rates and increased need for multiple treatments 1