Surgical classification of renal calculi

A classification of renal calculi is presented. 'C' describes the morphology, size and topography of the stone in five descriptive categories; the letters 'P', 'S', 'M', 'I' indicate the pelvis, the superior, middle and inferior calices, respectively, and complete the topographic description. The letter 'E' stands for the excretory tract; the symbols + and - are added to indicate the presence or absence of dilatation and the small letters e and i indicate the intra- and extrarenal position of the pelvis. 'R' points out the number of surgical recurrences. In conclusion, the letter 'P' indicates the functional status of the parenchyma, and the numbers 1, 2, 3 refer to a normally functioning kidney; moderate renal insufficiency, or serious renal insufficiency. 'U' symbolizes a solitary anatomical or functional kidney.