How effective is ESWL for kidney stones?

For 9 out of 10 patients who have kidney stones smaller than 10 mm (0.4 in.)--either in the kidney or in the ureter--ESWL gets rid of all of the stone or leaves only small fragments that don't cause any symptoms.

The outcome of Extracorporeal Shock-Wave Lithotripsy (ESWL) is dependent on a variety of factors, including the stone size, composition, location, and the anatomy of the collecting system. ESWL is generally most effective for stones that are less than 1.5 to 2.0 cm in diameter. Stones composed of uric acid, calcium oxalate dihydrate, struvite (magnesium ammonium phosphate), and calcium oxalate monohydrate are more readily fragmented with ESWL. Stones composed of cystine and calcium phosphate (brushite) are the most resistant to shock waves. The outcome for patients with lower pole kidney stones is generally worse than the outcome for those with stones in other locations in the kidney. Therefore, ESWL should be limited to stones less than 1cm, if the stone is in the lower pole.