[Types of kidney calculi. Relationship with urinary biochemistry]

To present a simple classification of the most frequent renal calculi that relates each type of calculus with the main possible etiologic factors linked to its formation (mainly urinary biochemical parameters).

The macro, microstructure and composition of 2,500 renal calculi were studied by appropriate combination of stereoscopic microscopy, IR spectroscopy and scanning electron microscopy + X-ray microanalysis. The information obtained were related with the main urinary biochemical parameters, determined by conventional analytical procedures.

Ten main categories of renal stones, covering over 95% of all conceivable calculi, are distinguished based on their composition and structure. Etiologic factors, mainly urinary biochemical parameters, leading to the formation of stone of every category are specified.

From the detailed study of the renal calculus important etiologic factors can be deduced. Such information complements and confirms the urinary biochemical studies. As a consequence, the corresponding treatment can be better established.