title: What imaging studies are necessary to determine outcome after ureteroneocystostomy?
abstract: OBJECTIVE
  After ureteroneocystostomy we have performed renal ultrasonography within the first 3 months to exclude hydronephrosis, voiding cystography after 3 months to exclude vesicoureteral reflux and subsequent ultrasonography to monitor the upper tracts. This study attempted to determine those patients at risk for hydronephrosis or recurrent vesicoureteral reflux.
  
  
  METHODS
  We studied the records of patients who underwent ureteroneocystostomy in the last decade at our institutions to find the incidence and degree of preoperative and postoperative hydronephrosis and vesicoureteral reflux. Results of initial postoperative imaging were compared to radiological imaging throughout followup (mean 2.3 years). Patients with postoperative reflux were evaluated for risk factors that differentiated them from others.
  
  
  RESULTS
  Excluding patients with neuropathic bladder or ureterocele, 167 underwent 278 ureteroneocystostomies at a mean followup of 26.5 months. Persistent vesicoureteral reflux was noted in 4 kidneys (1.4%) and contralateral reflux developed in 3 of the 48 cases (6.3%) of unilateral ureteroneocystostomy. There was no statistical difference in success rates among cross-trigonal, ureteral advancement or extravesical techniques. New onset mild hydronephrosis in 13 kidneys (4.7%) at the initial followup study (mean 1.6 months) completely resolved in 12 and remained mild in 1. No patient had progression of existing hydronephrosis and 1 had recurrent vesicoureteral reflux after initial negative cystography. Risk factors for postoperative reflux or hydronephrosis were preoperative dysfunctional voiding, preoperative hydronephrosis or scarring on sonography and postoperative urinary tract infection. None of the 88 patients without these risk factors had postoperative hydronephrosis or reflux. All patients with persistent, contralateral or recurrent reflux were selected using these criteria (p < 0.003).
  
  
  CONCLUSIONS
  Complication rates after nontapered ureteroneocystostomy in children without neuropathic bladder are quite low. Mild postoperative hydronephrosis was not clinically significant in our patients. Children with abnormal preoperative ultrasound or dysfunctional voiding are identified as a high risk group for postoperative hydronephrosis or recurrent reflux. All other patients received little benefit from postoperative imaging, suggesting that further evaluation of this group is necessary only in the presence of a postoperative urinary tract infection.
authors.affiliation: Section of Pediatric Urology, University of Michigan, Ann Arbor, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Bomalaski
authors.forename: M L
authors.initials: ML
authors.lastname: Ritchey
authors.forename: D A
authors.initials: DA
authors.lastname: Bloom
mesh_terms: D002648:Child; D003559:Cystostomy; D005500:Follow-Up Studies; D006801:Humans; D006869:Hydronephrosis / Q000000981:diagnostic imaging / Q000453:epidemiology; D015994:Incidence; D011182:Postoperative Care; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000453:epidemiology; D011859:Radiography; D012307:Risk Factors; D014463:Ultrasonography; D014519:Ureterostomy; D014718:Vesico-Ureteral Reflux / Q000601:surgery*