[Prognostic factors influencing the growth of renal calculi]

Factors influencing the growth of renal calculi were examined. In order to calculate the volume of stone on X-ray film, stones obtained from open operation or spontaneous passage were measured long (a) and short (b) diameter, and equation to obtain stone volume was assumed. Stone volume = 0.43 (pi ab (a + b))/12 + 0.04 was the mostly related to the volume measured by water volume, when size was less than 2 cm in diameter. Using the equation, factors influencing the growth of renal calculi of 136 kidney, which were followed over 6 months, were studied with monovariate analysis. Of the 136 kidneys, 36 have calcium oxalete stones, 54 have mixed stones with calcium oxalate and calcium phosphate, 3 have mixed stones with calcium oxalate and uric acid, and other 43 have stones with unknown composition. Uric acid stones, cystine stones and infectious stones were excluded in the study. Growth of stone was greater in male than in female. Pelvic stones grew rapidly than renal caliceal stones. The patients were divided into two groups by growth rate; non growing (< 10%/year), and growing group (> 10%/year), respectively. Excretion of urinary calcium was high in the growing group. Urinary magnesium/calcium was low in the growing group. When divided into two groups by growth volume; non growing (< 0.005 cm3/year), and growing group (> 0.005 cm3/year), respectively, excretion of urinary calcium was high in the growing group and urinary magnesium/calcium was low in the growing group.(ABSTRACT TRUNCATED AT 250 WORDS)