title: Postoperative ureteral obstruction after subureteral injection of dextranomer/hyaluronic Acid copolymer.
abstract: OBJECTIVE
  Subureteral injection of dextranomer/hyaluronic acid copolymer is widely accepted for the treatment of primary vesicoureteral reflux. Few studies document the incidence of surgically relevant postoperative obstruction or the characteristics of patients at risk.
  
  
  METHODS
  Four institutions had reported surgically relevant postoperative obstruction to representatives of Q-Med Scandinavia, the manufacturers of Deflux (dextranomer/hyaluronic acid). All children undergoing dextranomer/hyaluronic acid injection at these institutions were evaluated in this study. Patients requiring postoperative stenting were retrospectively reviewed for pertinent history, volume injected, technique of injection, duration of symptoms before intervention, duration of intervention and final outcome.
  
  
  RESULTS
  A total of 745 patients (1,155 ureters) underwent injection. Five patients (6 renal units, 7 ureters) required stenting for obstructive symptoms and hydronephrosis, of whom 4 immediately became symptomatic. All patients had been injected with up to 1 ml dextranomer/hyaluronic acid. Four patients (80%) had either a neurogenic bladder or dysfunctional voiding. All stents were placed and removed without complications, with complete resolution of symptoms in all patients. Length of stenting ranged from 2 to 6 weeks. No patient required open surgery. One of 2 patients undergoing postoperative voiding studies had development of recurrent vesicoureteral reflux.
  
  
  CONCLUSIONS
  Dextranomer/hyaluronic acid injection is associated with a small risk of postoperative ureteral obstruction requiring endoscopic intervention, with an overall incidence of less than 0.7% of patients injected. Patients with voiding dysfunction or neurogenic bladder may be at increased risk. Intervention with temporary ureteral stenting is effective, technically simple and curative.
authors.affiliation: Department of Urology, Children's Hospitals, Minneapolis/St. Paul, Minnesota, USA. dvandersteen@pediatricsurgicalassociates.com
authors.forename: David R
authors.initials: DR
authors.lastname: Vandersteen
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Routh
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Kirsch
authors.forename: Hal C
authors.initials: HC
authors.lastname: Scherz
authors.forename: Michael L
authors.initials: ML
authors.lastname: Ritchey
authors.forename: Ellen
authors.initials: E
authors.lastname: Shapiro
authors.forename: James J
authors.initials: JJ
authors.lastname: Wolpert
authors.forename: Heidi
authors.initials: H
authors.lastname: Pfefferle
authors.forename: Yuri
authors.initials: Y
authors.lastname: Reinberg
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003911:Dextrans / Q000008:administration & dosage* / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000008:administration & dosage* / Q000009:adverse effects*; D015994:Incidence; D007223:Infant; D007267:Injections; D008297:Male; D019919:Prosthesis Implantation; D012189:Retrospective Studies; D012307:Risk Factors; D015607:Stents; D016896:Treatment Outcome; D014517:Ureteral Obstruction / Q000139:chemically induced* / Q000453:epidemiology / Q000601:surgery; D014718:Vesico-Ureteral Reflux / Q000628:therapy*
chemical_list: D003911:Dextrans; C487487:dextranomer-hyaluronic acid copolymer; D006820:Hyaluronic Acid