ABSTRACT
Objective To analyze the related factors that influence the stone free rate ( SFR) in flexible ureteroscopic lithotripsy ( FURL ) and develop a stone free index ( SFI ) model to estimate and predict the outcome of FURL.Methods A total of 393 patients receiving FURL were included in this study from May 2013 to August 2014.All patients′and calculous characteristics were recorded.It was evaluated the correlation of one-stage SFR with body mass index, the degree of hydronephrosis, the sterile urine, the renal insufficiency, the stone location, the stone number, the cumulative stone diameter ( CSD) , the stone density, the average of CT values, the minimum angle of pelvis ureter long axis with lamp long axis, the average length of stone located calyx-neck, and the minimum ratio of stone located calyx-neck′width with calyx′width.Multivariate regression analysis was used to analyze the relationship between preoperative characteristics and the SFR.Results The one-stage postoperative SFR in our study was 92.4% ( 363/393).We found that the staghorn stone, bacteriuria, CSD, average of CT values, the average length of stone located calyx-neck, the minimum ratio of stone located calyx-neck′width with calyx′width were significantly correlated with the postoperative SFR ( P 7.5 meant a relatively high SFR ( SFR>85%) of FURL.Conclusions A SFI model using preclinical data was developed to predict the postoperative outcome of FURL, as well as the one-stage SFR.This model needs further prospective studies in the future.