Characterization of deposits on double J stents

We have characterized the types of encrustations that form on ureteral stents. The deposit that generates blocks is composed of hydroxyapatite/magnesium ammonium phosphate (44%). Calcium oxalate dihydrate was also detected at a high degree of encrustation (13%). Hydroxyapatite deposits, also of high degree of encrustation (13%) are generated due to their formation as a consequence of persistently high urinary pH values. The formation of large uric acid deposits (31%) must be attributed to the persistence of urinary $\mathrm{pH} < 5.5$. To avoid development of encrustations of ureteral stents, urinary calcium levels and urinary pH control should be carried out, avoiding urinary infections.