When (and how) to surgically treat asymptomatic renal stones.

Asymptomatic renal stones are identified in 8-10% of screened populations. With the increasing utilization of CT, the number of patients seeking urologic care for incidentally diagnosed renal calculi is likely to increase. Such patients present an important management dilemma: differentiating those to treat surgically from those who can be safely observed. Observational studies have revealed that approximately 50% of asymptomatic stones will progress, but most will not require surgery. Stones >15 mm in diamater and located in the renal pelvis are at highest risk of progression. Although no guidelines exist for the optimal monitoring regimen for asymptomatic stones, follow-up studies may include serum creatinine, plain radiography, ultrasonography, and CT. Shock wave lithotripsy (SWL) does not seem to offer significant benefit over observation for asymptomatic calyceal stones. Percutaneous nephrolithotomy does improve stone-free rates compared to SWL or observation. Additional research is needed to characterize the role of ureteroscopic management of asymptomatic renal stones.