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Preoperative factors predicting spontaneous clearance of residual stone fragments after flexible ureteroscopy
Author(s) -
Ito Hiroki,
Kuroda Shinnosuke,
Kawahara Takashi,
Makiyama Kazuhide,
Yao Masahiro,
Matsuzaki Junichi
Publication year - 2015
Publication title -
international journal of urology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 67
eISSN - 1442-2042
pISSN - 0919-8172
DOI - 10.1111/iju.12690
Subject(s) - medicine , ureteroscopy , hydronephrosis , urology , clearance , residual , ureter , logistic regression , radiology , surgery , urinary system , algorithm , computer science
Objective To investigate factors predicting spontaneous clearance of residual renal fragments after flexible ureteroscopy. Methods Among 546 patients who underwent lithotripsy with flexible ureteroscopy, 81 had residual renal fragments, as determined by kidney–ureter–bladder films on postoperative day 1. The final outcome was determined at 3 months after the last flexible ureteroscopy session using non‐contrast computed tomography. Patient characteristics and preoperative factors were analyzed using the unpaired t ‐test and χ 2 ‐test. Correlations between the possible predictive factors and the spontaneous clearance of residual renal fragments after flexible ureteroscopy were analyzed using a multivariate logistic regression model with backward selection. Results Non‐contrast computed tomography at postoperative month 3 showed that 33 cases (40.7%) had spontaneous clearance of residual renal fragments, whereas 48 (59.3%) showed non‐clearance. Significant differences were found between these cases in terms of stone number, stone location, presence of lower pole calculi and preoperative stent placement. Multivariate assessment showed that stone number ( P = 0.004), presence of lower pole calculi ( P = 0.021) and presence of hydronephrosis ( P = 0.024) were independent predictors of the spontaneous clearance of residual renal fragments after flexible ureteroscopy. Conclusions Stone number, presence of lower pole calculi and presence of hydronephrosis are independent predictive factors of the spontaneous clearance of residual renal fragments after flexible ureteroscopy.