Composition of kidney stone fragments obtained after extracorporeal shock wave lithotripsy.

Background: The objective of this study was to determine the composition of kidney stone fragments obtained after extracorporeal shock wave lithotripsy (ESWL).

Methods: Kidney stone fragments from 25 patients with urolithiasis treated with ESWL were submitted for morphological analysis. The composition was determined for all the recovered fragments.

Results: Thirteen patients (52%) had pure stones. The most common type of pure stone was calcium oxalate (61.6%), of which half was the monohydrate type (COM) and half was the dihydrate type (COD). The other pure stones consisted of either uric acid (30.8%) or struvite (7.6%). For mixed stones, the most frequently observed component was COM or COD (50%), followed by a mixture of COD and carbapatite (25.1%).

Conclusions: Our findings indicate that the composition of kidney stone fragments recovered after ESWL can be determined. Knowledge of stone composition is fundamental to understand the etiology of lithogenesis.