Classification of Stones According to Michel Daudon: A Narrative Review

Abstract

Context: Morphoconstitutional analysis of urinary stones is perhaps the most important examination in the evaluation of a patient with urolithiasis.

Objective: A comprehensive stone classification system was developed in the early 1990s by Michel Daudon, which included the main types of stones and their possible physiopathogenic origin.

Evidence acquisition: A narrative review of the articles published about this classification was conducted, without time limit.

Evidence synthesis: Two analytical steps are needed for the classification process: the microscopic examination, which gives the stone morphology, and the physical analysis, which provides the stone constitution. Upon completion of a full analysis, knowledge of the principal crystal species of the stone is acquired. In addition, this analysis highlights the possible causes of the lithogenic process, taking in account less frequent, but severe, pathologies.

Conclusions: The aim of this report is to summarize the principal etiological causes for urinary stone formation thanks to the morphoconstitutional analysis and to present its contribution in the field of urinary stones.

Patient summary: We looked at all types of stones and found that their origin varies according to the underlying pathology of the patient.

Keywords: Classification; Endoscopic recognition; Stone analysis; Stone morphology; Urinary stones.