Analysis of urinary calculi in adults. Attempt of correlations between morphology and composition.

The analysis of 322 urinary calculi in adults by microdissection, infrared spectromorphometry and microchemistry has shown that stones could be classified in several groups according to their morphology and composition: 8 morphological types have been defined (2 for the oxalic, 2 for the uric, 2 for the phosphatic and 2 for the cystinic stones). Correlations between morphology and composition have been established dividing the calculi into 10 categories, 4 for the pure forms and 6 for the mixed forms; the total includes approximately 94% of the calculi analyzed. An 11th category gathering various lithiases (rare or with multiple components) represents 6% of the cases. Moreover, the study of the localization of the component in stones emphasizes the high frequency of Ca phosphates in the nucleus of oxalic lithiases: 80% in mixed forms, in which the oxalate is the main constituent.