What is the recommended treatment for a patient with kidney stones, specifically considering lithoplaxy (percutaneous nephrolithotomy, PCNL) as a potential option?

Lithoplaxy (Percutaneous Nephrolithotomy) for Kidney Stones

Percutaneous nephrolithotomy (PCNL) should be offered as first-line therapy for renal stones >20 mm, achieving stone-free rates of 87-94%, while ureteroscopy (URS) or shock wave lithotripsy (SWL) are preferred for stones ≤20 mm. 1, 2

Treatment Algorithm Based on Stone Size

Stones ≤10 mm

• URS or SWL are both acceptable first-line options, with URS providing higher stone-free rates (90% vs 72%) but SWL offering somewhat better quality of life outcomes 2, 3
• For lower pole stones specifically in this size range, URS achieves approximately 81% stone-free rates compared to 58% for SWL 2, 3
• Patient body habitus, skin-to-stone distance, and stone composition should guide the choice between these modalities 2

Stones 10-20 mm

• URS or PCNL are recommended, with median success rates of 81% for URS and 87% for PCNL 2
• SWL should NOT be offered as first-line therapy for stones >10 mm due to significantly lower success rates (dropping to 58% for 10-20 mm stones and only 10% for stones >20 mm) 2
• For lower pole stones in this range, PCNL becomes increasingly favorable given the gravity-dependent drainage issues that impair fragment clearance 2

Stones >20 mm

• PCNL is the definitive first-line therapy, achieving stone-free rates of 87-94% compared to 75-81% for URS 2
• PCNL requires fewer secondary interventions and provides superior outcomes for large stone burden 1, 2
• Open/laparoscopic/robotic surgery should NOT be offered as first-line therapy except in rare cases of anatomic abnormalities requiring concomitant reconstruction 1

Critical Technical Considerations for PCNL

Mandatory Procedural Standards

• Flexible nephroscopy must be routinely performed during PCNL to access stone fragments in areas inaccessible by rigid nephroscope 1, 2
• Normal saline irrigation must be used to prevent electrolyte abnormalities and hemolysis 1, 2
• Multiple percutaneous access tracts may be necessary to facilitate complete stone removal 1
• Second-look flexible nephroscopy via the preexisting nephrostomy tract should be used if residual stones are identified on post-PCNL imaging 1

Antibiotic Prophylaxis Requirements

• Antimicrobial prophylaxis is mandatory for PCNL, administered within 60 minutes of the procedure 1
• A single oral or IV dose covering gram-positive and gram-negative uropathogens is recommended 1
• If purulent urine is encountered, immediately abort the procedure, establish drainage (stent or nephrostomy), culture the urine, and continue broad-spectrum antibiotics 1

Post-Procedure Management

• Nephrostomy tube placement after uncomplicated PCNL is optional 2
• Residual fragments, especially infection stones, should be removed via second-look procedures to prevent stone growth, recurrent UTI, and renal damage 1

Absolute Contraindications to PCNL

• Untreated urinary tract infection (relative contraindication for URS) 2
• Pregnancy 2
• Anticoagulation or antiplatelet therapy that cannot be discontinued - in these cases, URS should be used as first-line therapy instead 1, 2

When PCNL Fails or Is Not Appropriate

• If initial SWL fails, endoscopic therapy (URS or PCNL) should be offered as the next treatment option, with success rates of 86-100% for PCNL and 62-100% for URS as secondary procedures 1
• For patients with negligible kidney function in the affected kidney, nephrectomy may be considered 2
• Open/laparoscopic/robotic approaches may be offered for patients who fail or are unlikely to have successful results with endoscopic methods, particularly with anatomic abnormalities requiring reconstruction 1, 2

Common Pitfalls to Avoid

• Do not use SWL monotherapy for staghorn or large cystine stones - outcomes are poor with stone-free rates inadequate for stones ≥25 mm 1
• Do not rely solely on CT imaging for stone size estimation - motion artifact can cause warping distortion making stones appear larger than actual size; correlate with KUB radiograph and ultrasound 4
• Do not perform "dust and go" approach except for large renal stones - complete stone removal is the goal 2
• Always use a safety guidewire during endoscopic procedures to facilitate rapid re-access if the primary working wire is lost 1