RESUMO
INTRODUCTION: To analyze the primary stone free rate (pSFR) of flexible ureterorenoscopy (fURS) in the treatment of renal stones and to identify clinical predictors for the primary freedom from renal stones. MATERIALS AND METHODS: Two hundred and seventy five patients, who underwent fURS for kidney stones were analyzed. RESULTS: Index stone size was 6 mm. The stone was located in the lower calyx in 48%. Ureteral access sheath was used in 97%. Operation time was 35 min and primary stone clearance was 83%. pSFR increased from 74% in 2012 to 83% in 2013 and 90% in 2014 (p = 0.001). Preoperative stenting, index stone size, cumulative stone size, lithotripsy, ureteral access sheath and operation time were significantly correlated with the pSFR by univariate analysis. Multivariate regression analysis showed index stone size, cumulative stone size, ureteral access sheath and operation time as independent parameters for pSFR. CONCLUSIONS: fURS for kidney stones is safe with a high pSFR. Clinical parameters for pSFR are stone size, use of ureteral access sheath and operation time. In future, the effective use of fURS for the removal of kidney stones needs to be checked by prospective randomized trials.
