title: Delayed redo pyeloplasty fails to recover lost renal function after failed pyeloplasty: early sonographic changes that correlate with a loss of differential renal function.
abstract: OBJECTIVE
  To evaluate changes in differential renal function (DRF), as a functional outcome, in children who underwent redo pyeloplasty for management of failed pyeloplasty and to examine the factors that affect functional outcomes.
  
  
  METHODS
  Between January 2002 and November 2010, a total of 18 patients who underwent redo pyeloplasty for persistent ureteropelvic junction obstruction after failed pyeloplasty were enrolled in this study. We assessed perioperative factors and evaluated changes in renal cortical thickness (RCT), renal function, and hydronephrosis by use of serial ultrasound and diuretic renography.
  
  
  RESULTS
  The mean follow-up period was 44.83±28.86 months. After redo pyeloplasty, prevention of further functional deterioration was observed in only 12 of the 18 patients. After dividing the patients according to this observation, we discovered significant differences in both change in DRF (dDRF) and change in RCT (dRCT) (difference between before and after initial pyeloplasty) between the two groups (p<0.001). Additionally, we noted a significant positive correlation between dRCT and dDRF. All patients showed improvements in hydronephrosis grade and relief of symptoms compared with before redo pyeloplasty.
  
  
  CONCLUSIONS
  Redo pyeloplasty should be considered in cases of failed pyeloplasty to preserve renal function and obtain relief from symptoms. If patients show severe deterioration of DRF or a decrease in RCT after initial pyeloplasty, preservation of DRF in these patients after redo pyeloplasty could be difficult. Therefore, redo pyeloplasty should be performed before severe deterioration of DRF or decrease in RCT.
authors: Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors: Doo Yong
authors: DY
authors: Chung
authors: Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors: Chang Hee
authors: CH
authors: Hong
authors: Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors: Young Jae
authors: YJ
authors: Im
authors: Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors: Yong Seung
authors: YS
authors: Lee
authors: Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors: Sang Woon
authors: SW
authors: Kim
authors: Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors: Sang Won
authors: SW
authors: Han
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006869:Hydronephrosis / Q000000981:diagnostic imaging / Q000209:etiology; D007223:Infant; D007668:Kidney / Q000000981:diagnostic imaging / Q000503:physiopathology*; D007672:Kidney Cortex / Q000473:pathology; D007677:Kidney Function Tests / Q000379:methods; D007682:Kidney Pelvis / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D011184:Postoperative Period; D011379:Prognosis; D012086:Reoperation / Q000009:adverse effects / Q000379:methods; D012189:Retrospective Studies; D017211:Treatment Failure; D016896:Treatment Outcome; D014463:Ultrasonography; D014517:Ureteral Obstruction / Q000150:complications / Q000473:pathology / Q000601:surgery*
keywords: Hydronephrosis; Radioisotope renography; Treatment failure