Correlations between crystalluria and composition of calculi.

The successful fragmentation of kidney stones by means of extracorporeal sh ock wave lithotripsy partly depends on stone composition. in case of incomp lete or coarse fragmentation, multiple urological procedures following ESWL may be necessary for removal of obstructive fragments. It is difficult to be sure that a given stone will be successfully destroyed. X-ray examinatio ns before treatment are useful to classify, calculi as calcium stones or no t. Nevertheless, such investigations are often not sufficient to identify t he main crystalline phases which form the stone and that can make it either resistant or friable to ESWL. Objective : The aim of this study was to compare crystalluria and stone com position in patients with kidney calculi. Material and Methods : Seventy-five untreated patients (54 males, 21 female s) were included. Their first morning urine was collected three days before surgical removal of the stone. Urine samples were kept at 4 degrees C duri ng 48 hours before examination. Results : Crystalluria occurred in 97.3% of urine specimens. Weddellite was the most frequent crystalline species found in urine (66.2%), followed by carbapatite (33.1%) and whewellite (23.1%). When compared to stone composit ion, crystalluria was mainly made of weddellite in urines from 68% of patie nts with weddellite-rich calculi. Stones from patients presenting with whew ellite crystals in urine were mainly composed of whewellite in 88.9% of cas es. Struvite stones were associated with struvite and carbapatite crystallu ria in 85.7% of cases. Conclusion : Crystalluria studies could be of clinical interest to predict the main crystalline phase of calcium-containing stones in order to define the best procedures for stone removal.