What are the treatment options for kidney stones (renal calculi)?

Treatment Options for Kidney Stones

The treatment of kidney stones should be based on stone size, location, and patient symptoms, with options ranging from conservative management to surgical intervention depending on these factors. 1

Conservative Management

• For asymptomatic, non-obstructing caliceal stones up to 15 mm, active surveillance is a viable option 1
• Medical expulsive therapy (MET) with alpha-blockers can facilitate stone passage, particularly for distal ureteral stones 1
• Spontaneous passage rates vary by stone size: 75% for stones <5 mm and 62% for stones ≥5 mm 1
• A "common sense diet" containing sufficient fluids, 1200 mg of calcium per day, and reduced amounts of animal protein and salt can reduce 5-year stone recurrence rates by 50% 2

Indications for Active Stone Removal

• Stone growth during observation 1
• Symptomatic stones causing pain or obstruction 1
• Associated urinary tract infection 1
• Specific vocational reasons (e.g., pilots, frequent travelers) 1
• Recent evidence shows that even nonobstructing renal stones can cause significant pain that improves after removal 3

Surgical Management Based on Stone Size and Location

For Stones ≤20 mm (Non-Lower Pole)

• Both shock wave lithotripsy (SWL) and ureteroscopy (URS) are acceptable first-line treatments 1
• URS provides higher single-procedure stone-free rates but has slightly higher complication rates 1

For Stones >20 mm

• Percutaneous nephrolithotomy (PCNL) should be offered as first-line therapy 1
• PCNL offers higher stone-free rates (94% vs. 75% for URS) and is less dependent on stone composition, density, and location 1

For Staghorn Calculi

• PNL (percutaneous nephrolithotomy) has emerged as the treatment of choice for staghorn calculi based on superior outcomes and acceptably low morbidity 4
• Recent advances in instrumentation and technique have improved stone-free rates and reduced morbidity, favoring PNL monotherapy 4
• SWL monotherapy should not be used for patients with staghorn or partial staghorn cystine stones 4

Procedural Considerations

Shock Wave Lithotripsy (SWL)

• Not recommended for stones >20 mm or for cystine staghorn calculi 1
• Routine pre-stenting is not recommended 1
• Alpha-blockers may be prescribed after SWL to facilitate passage of stone fragments 1

Ureteroscopy (URS)

• Requires a safety wire during the procedure 1
• Laser or pneumatic lithotripsy may be used with semi-rigid ureteroscopes, while laser lithotripsy is preferred for flexible URS 1
• Routine stent placement is not recommended after uncomplicated URS 1

Percutaneous Nephrolithotomy (PCNL)

• First-line therapy for stones >20 mm 1
• Flexible nephroscopy during PNL can help retrieve stones remote from the access tract 4
• Complications include fever (10.8%), transfusion (7%), thoracic complications (1.5%), and sepsis (0.5%) 1

Special Considerations

• For septic patients with obstructing stones, urgent decompression of the collecting system with either percutaneous drainage or ureteral stenting is indicated before definitive treatment 4
• Open surgery is rarely required (used in <1% of patients) but may be considered in cases of extremely large stones, complex collecting system issues, excessive morbid obesity, or extremely poor function of the affected renal unit 4
• Nephrectomy may be considered when the involved kidney has negligible function 1
• For patients on antithrombotic therapy that cannot be discontinued, flexible URS is recommended 1

Treatment Decision Factors

• Patient preferences play an important role in treatment selection, with some patients prioritizing higher stone-free rates despite greater invasiveness, while others prefer less invasive approaches 5
• Stone size significantly predicts the need for future surgical intervention, with stones >4 mm (for residual fragments) or >7 mm (for pediatric population) more likely to require intervention 6
• For asymptomatic lower pole stones <1 cm, both URS and SWL have comparable outcomes 6