A new system for descriptive classification of stones in the upper urinary tract.

A descriptive classification is proposed to stratify upper urinary tract stones by their number, size and location. The system considers the minimal but most important factors regarding the choice of surgical treatment and its success. Its principle is adaptable to more complex staging systems already existing. Practical use of the system has shown it to reflect clinical events, and its simplicity offers an opportunity for compliance in routine clinical study. It facilitates easy computerized stratification of stones in the upper urinary tract.