Comparison of chemical compositions of multiple or recurrent urinary stones

The chemical compositions of multiple or recurrent stones, of which the central areas were analyzed by infrared spectroscopy, were compared in each of 110 cases afflicted with upper urinary tract calculi of every type. Nearly all central areas of multiple stones or of initial and recurrent stones in each individual were qualitatively shown to have the same chemical composition except for only 8 cases. Sixty-seven of these one hundred and ten cases had multiple or recurrent stones composed of mixed calcium oxalate-calcium phosphate, and these stones were also used in the measurement of the mixture ratio of phosphate/oxalate from previously formulated infrared spectrum charts. The fairly similar ratios were found in most multiple stones. In the recurrent stones, however, the decreasing ratios were demonstrated in cases with initial stones in the kidney, whereas the increasing ratios in all cases with initial stones in the opposite ureters, and in more than half of the cases with initial stones in the ipsilateral ureters.