RESUMO
In a prospective study, 24-hours urinary excretions of calcium, phosphate, and uric acid were compared in two groups of male patients with renal stones before and after surgical treatment. Group A comprised 39 patients who had complete surgical clearance of the stones. Group B consisted of 15 patients with residual stones. 24-Hours urinary collections were obtained in each patient before and after stone removal. In Group A, the mean [ +/- SEM] urinary excretions of calcium and phosphate rose significantly [P< 0.05] after surgery but uric acid levels did not changes significantly. In Group B, the mean [ +/- SEM] postoperative urinary excretions of calcium, phosphate, and uric acid were not significantly different [P> 0.05] from preparative values. The findings in this study suggest that, in view of the utilization of these urinary solutes in the process of stone growth, preoperative urinary estimation is misleadingly low. It is therefore advisable to carry out the 24-hours urinary estimations of calcium, phosphate, uric acid, and perhaps other risk factors only after complete surgical clearance of the stones, because at this time urinary excretion of these solutes will not be modified by the presence of the stones in the kidneys