At what size do we intervene for staghorn calculi?

From the Guidelines

Intervention for staghorn calculi is generally recommended when the stone burden exceeds 500 square millimeters, or in cases of significant symptoms or complications, due to their high risk of morbidity and mortality.

Key Considerations

• Staghorn calculi are large branched stones that fill part or all of the renal collecting system and are typically composed of struvite or calcium phosphate.
• The standard treatment is surgical removal, with percutaneous nephrolithotomy (PCNL) being the first-line approach for most patients, as it offers higher stone-free rates compared to shock wave lithotripsy (SWL) monotherapy 1.
• For very large or complex staghorn calculi, a combination approach may be needed, including PCNL followed by flexible ureteroscopy or extracorporeal shock wave lithotripsy (ESWL) for residual fragments, with PCNL-based therapy preferred due to its lower morbidity compared to open surgery 1.
• Conservative management is rarely appropriate as untreated staghorn calculi can lead to recurrent infections, renal function deterioration, and sepsis.

Treatment Approach

• Percutaneous nephrolithotomy (PCNL) should be the first treatment utilized for most patients, except for some patients with extremely large and/or complex staghorn stones, where open surgery may be considered 1.
• If combination therapy is undertaken, percutaneous nephroscopy should be the last procedure for most patients, allowing for accurate assessment of stone-free status and a greater chance of achieving this state 1.
• Shock wave lithotripsy (SWL) monotherapy may be considered in patients with small volume staghorn calculi (< 500 square millimeters) with normal collecting-system anatomy, but adequate drainage of the treated renal unit should be established before treatment 1.

From the Research

Intervention Size for Staghorn Calculi

• The size at which intervention is recommended for staghorn calculi can vary depending on several factors, including the location and composition of the stone, as well as the patient's overall health.
• According to a study published in 2002 2, percutaneous nephrolithotomy (PCNL) can be effective for staghorn calculi with a cumulative stone burden of ≥5 cm.
• Another study from 1993 3 suggests that PCNL is a good option for stones larger than 3 cm, with a complete clearance rate of 93% for stone loads larger than 3 cm.
• A 2011 study 4 evaluated the feasibility of retroperitoneal laparoscopic anatrophic nephrolithotomy for large staghorn calculi, with a mean stone size of 52 mm.
• Other studies, such as those published in 1986 5 and 1997 6, also discuss the treatment of staghorn calculi, including the use of combined percutaneous and extracorporeal shock wave lithotripsy, and the importance of active treatment for struvite staghorn calculi.

Key Findings

• PCNL can be effective for staghorn calculi with a cumulative stone burden of ≥5 cm 2.
• Stones larger than 3 cm may require PCNL, with a complete clearance rate of 93% 3.
• Retroperitoneal laparoscopic anatrophic nephrolithotomy may be a viable option for large staghorn calculi 4.
• Combined percutaneous and extracorporeal shock wave lithotripsy can be used to treat staghorn calculi, with a lower morbidity rate than anatrophic nephrolithotomy 5.
• Active treatment is often necessary for struvite staghorn calculi, which can pose a threat to the kidney and patient 6.