What are the surgical indications for nephrolithiasis?

Surgical Indications for Nephrolithiasis

Surgical intervention for nephrolithiasis is indicated for symptomatic stones causing obstruction, stones with associated infection, stones demonstrating growth, stones unlikely to pass spontaneously (>10 mm), and in specific high-risk clinical scenarios including solitary kidney or bilateral obstruction. 1, 2

Absolute/Urgent Indications

Emergency decompression is mandatory in the following scenarios:

• Obstructing stone with suspected infection/sepsis - requires urgent drainage via nephrostomy tube or ureteral stent before definitive stone treatment 1, 2
• Anuria in an obstructed kidney - immediate decompression required 2
• Solitary kidney with obstruction - urgent intervention needed to preserve renal function 2
• Bilateral ureteral obstruction - emergent drainage required 2

Symptomatic Indications

Active stone removal is indicated when:

• Intractable pain despite medical management - conservative measures have failed 2
• Progressive hydronephrosis or declining renal function - ongoing obstruction causing kidney damage 2
• Urinary tract infection with obstruction - infection cannot be adequately treated without relieving obstruction 2, 3

Stone-Specific Indications

Renal Stones

For asymptomatic renal stones, surgical treatment is indicated for:

• Stone growth on follow-up imaging - demonstrates active disease progression 1, 2
• Associated infection - stones serving as nidus for recurrent UTI 1
• High-risk stone formers - recurrent stone disease with metabolic abnormalities 2
• Vocational reasons - occupations where stone passage would be dangerous (pilots, remote workers) 1

Conservative observation is problematic because spontaneous passage occurs in only 3-29% of cases, symptoms develop in 7-77%, stone growth occurs in 5-66%, and 7-26% ultimately require surgery anyway. 2

Size-Based Criteria

Stones >10 mm have very low spontaneous passage rates and warrant intervention:

• Stones >20 mm - PCNL is first-line therapy regardless of location 1
• Stones 10-20 mm - flexible ureteroscopy or PCNL recommended, particularly for lower pole locations 1, 2
• Stones <10 mm - may be observed if asymptomatic, but intervention indicated if symptomatic 1

Ureteral Stones

Active removal indicated when:

• Conservative management fails after 4-6 weeks - maximum duration to prevent irreversible kidney injury 1, 2
• Stones >10 mm - unlikely to pass spontaneously 1
• Complications arise during medical expulsive therapy - including worsening pain, infection, or obstruction 2

For distal ureteral stones >10 mm, ureteroscopy is first-line treatment across all major guidelines. 1

Special Clinical Scenarios

Additional indications include:

• Staghorn or partial staghorn calculi - require complete removal via PCNL to prevent chronic kidney disease 4, 3
• Infection stones (struvite) - complete eradication required as medical management has minimal role 3
• Chronic kidney disease with stones - PCNL indicated to preserve remaining function 4
• Residual fragments post-intervention - if symptomatic or causing recurrent infection 1
• Negligible kidney function - nephrectomy may be performed when kidney is non-functional 1

Conservative Management Contraindications

Conservative management should NOT be attempted when:

• Stones >10 mm - spontaneous passage extremely unlikely 2
• Infection present with obstruction - requires urgent drainage 1
• Solitary or transplant kidney - cannot risk prolonged obstruction 2
• Bilateral obstruction - immediate intervention required 2
• Progressive renal deterioration - ongoing damage occurring 2

Common Pitfalls

Key considerations to avoid complications:

• Do not delay intervention beyond 4-6 weeks - irreversible kidney injury can occur with prolonged obstruction 1, 2
• Always obtain urinalysis and culture before intervention - unrecognized infection increases sepsis risk 1
• Do not offer SWL for stones >20 mm - significantly reduced stone-free rates and increased need for multiple treatments 1
• Recognize that lower pole stones have worse outcomes with SWL - anatomic factors impair fragment clearance 1
• Obtain non-contrast CT before PCNL - essential for surgical planning 1