What is the preferred treatment for renal calculus, Percutaneous Nephrolithotomy (PCNL) or Retrograde Intrarenal Surgery (RIRS)?

PCNL vs RIRS for Renal Calculus

Direct Answer

For renal stones >20mm, PCNL should be offered as first-line therapy due to superior stone-free rates and fewer secondary interventions, while RIRS is preferred for stones ≤20mm given comparable efficacy with lower morbidity. 1

Treatment Algorithm Based on Stone Size

Stones ≤20mm

• RIRS or SWL are appropriate first-line options, with RIRS providing higher stone-free rates (90% vs 72% for ESWL). 1
• For lower pole stones 10-20mm specifically, median success rates are: RIRS/URS (81%) vs PCNL (87%), making either option reasonable. 1
• RIRS offers the advantage of lower morbidity in this size range. 1

Stones >20mm

• PCNL achieves stone-free rates of 87-94% compared to 75-81% for RIRS in this size range. 1
• For stones 2.3cm (23mm), PCNL provides a 94% stone-free rate compared to 75% with RIRS in randomized trials. 2
• PCNL requires fewer secondary interventions: 153 fewer per 1000 patients compared to RIRS (absolute difference 15.3%). 3

Comparative Outcomes Analysis

Stone-Free Rates

• PCNL improves stone-free rates by 10% absolute difference (RR 1.13,95% CI 1.08-1.18) compared to RIRS. 3
• This advantage is most pronounced for stones >20mm where PCNL's success is less dependent on stone composition, density, and location. 2

Safety Profile

• PCNL and RIRS have equivalent major complication rates (RR 0.86,95% CI 0.59-1.25). 3
• PCNL has higher overall complications (RR 1.51,95% CI 1.24-1.83), specifically Clavien-Dindo grade 2 complications. 4
• No difference exists in ureteral stricture rates between the two approaches (RR 0.93,95% CI 0.39-2.21). 3

Secondary Interventions

• PCNL reduces need for secondary interventions by 15.3% absolute difference (RR 0.31,95% CI 0.17-0.55). 3
• Only 26% of RIRS patients require a second procedure when staged RIRS is planned. 4
• When RIRS is repeated up to two times if needed, stone-free rates become equivalent to single-stage PCNL. 4

Hospital Stay

• PCNL extends hospital stay by 1.04 days compared to RIRS (95% CI 0.27-1.81 days). 3
• This represents a clinically meaningful difference exceeding the predefined threshold of one day. 3

Special Considerations and Contraindications

PCNL Contraindications

• Anticoagulation or antiplatelet therapy that cannot be discontinued. 1
• Untreated urinary tract infection (absolute contraindication). 1
• Pregnancy. 1

RIRS Relative Contraindications

• Untreated urinary tract infection (relative contraindication). 1

Urgent Situations

• For obstructing stones with suspected infection, urgent drainage via stent or nephrostomy tube is mandatory before definitive treatment with either modality. 1, 2

Technical Considerations

PCNL Technique

• Flexible nephroscopy should be routine during PCNL to access fragments in areas inaccessible by rigid nephroscope. 1
• Normal saline irrigation must be used to prevent electrolyte abnormalities and hemolysis. 1
• Nephrostomy tube placement after uncomplicated PCNL is optional. 1

RIRS Technique

• Ho:YAG laser is the gold standard for lithotripsy, with thulium fiber laser offering comparable efficacy. 1
• Routine post-procedure stenting is unnecessary after uncomplicated RIRS and may increase morbidity. 1

Common Pitfalls to Avoid

• Do not offer SWL as first-line therapy for stones >20mm due to unacceptably low success rates (10% for stones >20mm). 1
• Do not perform single-stage RIRS for stones >20mm without counseling patients about the likely need for staged procedures. 4
• Avoid proceeding with definitive stone treatment in the presence of infection without first achieving drainage and antibiotic control. 1, 2

Clinical Decision Framework

For stones ≤20mm: Choose RIRS for shorter hospital stay and lower morbidity, accepting slightly lower single-procedure stone-free rates. 1, 3

For stones >20mm: Choose PCNL for superior stone-free rates and fewer secondary interventions, accepting longer hospital stay. 1, 2, 3

For stones >20mm in patients who cannot tolerate longer hospitalization or have PCNL contraindications: Staged RIRS (up to two procedures) achieves equivalent stone-free rates to PCNL. 4