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

Treatment Selection for Renal Stones: RIRS vs PCNL

Direct Answer

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

Treatment Algorithm Based on Stone Burden

Stones ≤20 mm

• RIRS or ESWL are appropriate first-line options for stones up to 20 mm, with RIRS providing higher stone-free rates (90% vs 72% for ESWL) 1, 2
• RIRS requires fewer repeat procedures and allows patients to become stone-free more quickly 3
• Patient quality of life measures may be somewhat better with ESWL, though intraoperative complications are only slightly higher with RIRS (not statistically significant) 3

Stones >20 mm

• PCNL is the recommended first-line therapy for total renal stone burden exceeding 20 mm 1
• PCNL achieves stone-free rates of 87-94% compared to 75-81% for RIRS in this size range 1, 2
• PCNL significantly reduces the need for secondary interventions (15.3% absolute reduction) compared to RIRS 4
• The stone-free rate advantage with PCNL represents a 10% absolute improvement over RIRS, exceeding the clinically meaningful threshold of 5% 4

Lower Pole Stones: Special Considerations

• For lower pole stones ≤10 mm: RIRS or ESWL are both acceptable 1, 2
• For lower pole stones >10 mm: ESWL should NOT be offered as first-line therapy due to success rates dropping to only 58% for 10-20 mm stones and 10% for stones >20 mm 1, 2
• For lower pole stones 10-20 mm: median success rates are PCNL 87%, RIRS 81%, ESWL 58% 2, 3

Comparative Safety Profile

Major Complications

• PCNL and RIRS have similar rates of major complications (approximately 3% vs 3.1%), with no clinically significant difference 4
• PCNL-specific complications include fever (10.8%), transfusion requirement (7%), and sepsis (0.5%) 3
• RIRS has lower overall complication rates, particularly for stones 2-3 cm (8.8% vs 13.5% for PCNL) 5

Hospital Stay

• PCNL extends hospital stay by approximately 1 day compared to RIRS (mean difference 1.04 days), which exceeds the clinically meaningful threshold 4
• This represents a trade-off between higher stone-free rates and longer recovery time 4

Ureteral Complications

• Both procedures have similar rates of ureteral stricture or injury (approximately 1.4% for both) 4

When RIRS May Be Considered for Larger Stones (2-4 cm)

Despite guideline recommendations favoring PCNL for stones >20 mm, emerging evidence suggests RIRS may be viable in select cases:

• Multistage RIRS achieves 81% stone-free rates for 2-4 cm stones with fewer complications than PCNL 6
• Average of 2.1 procedures per patient required to achieve stone-free status 6
• RIRS offers advantages when PCNL is contraindicated: patients on anticoagulation that cannot be discontinued, anatomic derangements preventing proper positioning, or patient preference for less invasive approach 1, 6

However, this approach requires patient counseling that multiple staged procedures will likely be necessary and complete stone-free status may not be achieved 1

Absolute Contraindications to Consider

PCNL Contraindications

• Anticoagulation or antiplatelet therapy that cannot be discontinued 1
• Untreated urinary tract infection 1
• Contractures, flexion deformities, or anatomic derangements preventing proper positioning 1
• Pregnancy 1
• Suspected malignant kidney tumor in access tract 1

RIRS Contraindications

• Untreated urinary tract infection (relative contraindication) 1
• General anesthesia risks in high-risk patients 1

Critical Pre-Treatment Steps

Before any definitive stone treatment, rule out obstructing stone with infection—if suspected, urgent drainage with nephrostomy tube or ureteral stent is mandatory 2, 3

• Delay definitive treatment until infection is controlled with appropriate antibiotics 2, 3
• Obtain CT imaging as gold standard for treatment planning and accurate stone burden measurement 3
• Measure stone in multiple dimensions using multiplanar CT for accurate representation of stone burden 3

Technical Considerations

PCNL Best Practices

• Flexible nephroscopy should be routine during PCNL to access fragments in areas inaccessible by rigid nephroscope 1, 2
• Normal saline irrigation must be used to prevent electrolyte abnormalities and hemolysis 1, 2
• Nephrostomy tube placement after uncomplicated PCNL is optional 1, 2
• Smaller access sheaths (<18 Fr) are increasingly used in adults, potentially reducing morbidity 1

RIRS Best Practices

• Ho:YAG laser is the gold standard for lithotripsy; thulium fiber laser offers comparable efficacy 1
• Routine pre-stenting is not required but may improve outcomes for renal stones 1
• Routine post-procedure stenting is unnecessary after uncomplicated procedures and may increase morbidity 1
• Stenting is advised only with trauma, residual fragments, bleeding, perforation, UTI, or pregnancy 1

Common Pitfalls to Avoid

• Do not offer ESWL as first-line therapy for stones >20 mm—success rates are unacceptably low and multiple treatments will be required 1, 2
• Do not routinely place stents before ESWL or after uncomplicated RIRS, as this increases morbidity without improving outcomes 3
• Do not select ESWL for obese patients or those with unfavorable skin-to-stone distance without recognizing this significantly reduces success rates 3
• Do not perform "dust and go" approach except for large renal stones—complete stone removal is the goal 1

Evidence Quality Considerations

The 2025 European Association of Urology guidelines 1 and 2016 American Urological Association guidelines 1 provide the strongest recommendations, both designating PCNL as first-line for stones >20 mm. A 2023 Cochrane systematic review of 42 trials (4571 participants) confirms PCNL improves stone-free rates by 10% absolute difference and reduces secondary interventions by 15.3% absolute difference, though with moderate-to-low certainty evidence due to study heterogeneity 4. The trade-off is one additional day of hospitalization 4.