CIPRIAN TODEA-MOGA, ORSOLYA MARTHA, IOAN SCARNECIU, CAMELIA CORNELIA SCARNECIU, LAURIAN MAXIM, COSTIN VLAD ANASTASIU, ALEXANDRU BANUTA, VERONICA GHIRCA, DAN LIVIU DOREL MISCHIANU, DANIEL PORAV-HODADE DOES THE COMPOSITION OF THE STONES COUNTS IN PATIENTS WHO UNDERWENT PERCUTANEOUS NEPHROLITHOTOMY? The aim of this study is to highlight the importance of percutaneous nephrolithotomy (PCNL) in the treatment of kidney stones with different chemical composition. We included in this study 200 patients with kidney stones who underwent PCNL. In most of the cases the stones were composed by calcium, usually calcium oxalate followed by struvite and uric acid component. The stones were mostly localized in the renal pelvis (142), inferior calyx (46) and ureteropelvic junction (4) and 28 cases with staghorn stones. Intraoperative complications were: migrating fragments (22%), hemorrhage (12%), lesions of the renal pelvis and difficulties of percutaneous access or dilatation (6%). The postoperative complications were: bleeding (20%), obstruction caused by stone fragments (22.5%), hydronephrosis (18%), fistula (13%). The average length of hospitalization after PCNL was 5.58 +/- 2.69 days SD. Stone-free rate was: 77.5%. PCNL is a safe and effective method of treatment for large and complex stones. Intra and postoperative complications after PCNL are not influenced directly by the chemical composition of the stones. It is important to evaluate the chemical composition of the stones in order to establish the treatment management and to recommend a proper conservative treatment in order to prevent the recurrence of the disease.