title: Correlation of vesicoureteral reflux with degree of hydronephrosis and the impact of antireflux surgery.
abstract: OBJECTIVE
  We correlated the degree of hydronephrosis (HN) to the grade of vesicoureteral reflux (VUR) and assessed the impact of antireflux surgery on the resolution/persistence of HN.
  
  
  METHODS
  Between 1997 and 2000, 308 patients (476 units) underwent antireflux surgery for primary or secondary VUR. Surgical procedures included extravesical reimplantation (291 ureters), intravesical reimplantation (48) and endoscopic polydimethylsiloxane injection (137). The degree of HN was categorized as mild (grade 1 to 2) or moderate/severe (grade 3 to 4). VUR was grade I in 44 cases, II in 145, III in 203 and IV to V in 84. Followup renal ultrasound was performed at 3 and 12 months postoperatively. Statistical analysis consisted of a contingency table and chi-square test for independence.
  
  
  RESULTS
  Preoperative HN existed in 123 refluxing units, and was mild in 4 (9%), 11 (7.5%), 39 (19%) and 28 (33%), and moderate/severe in 0, 2 (1.4%), 14 (7%) and 25 (30%) of grade I, II, III and IV to V VUR cases, respectively. The degree of preoperative HN correlated with VUR grade (p <0.0001). At 3 months postoperatively HN resolved in 50.4%, improved in 16.3%, persisted in 30% and worsened in 3.3% of units. At 15 months postoperatively HN resolved in 80 units (65%) and persisted in 43 (35%). Patients with preoperative moderate/severe HN constituted 56% of those with persistent HN.
  
  
  CONCLUSIONS
  Our data indicate that the presence and degree of preoperative hydronephrosis are closely related to VUR grade. Furthermore, antireflux surgery resulted in a high resolution rate of hydronephrosis. Persistent postoperative hydronephrosis did not require any intervention.
mesh_terms: D000283:Administration, Intravesical; D002648:Child; D002675:Child, Preschool; D003558:Cystoscopy; D003627:Data Interpretation, Statistical; D004129:Dimethylpolysiloxanes / Q000008:administration & dosage; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006869:Hydronephrosis / Q000145:classification / Q000453:epidemiology / Q000601:surgery*; D007223:Infant; D008297:Male; D009864:Ontario; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology*; D019919:Prosthesis Implantation; D012189:Retrospective Studies; D012828:Silicones / Q000008:administration & dosage; D014513:Ureter / Q000601:surgery; D001743:Urinary Bladder / Q000601:surgery; D014718:Vesico-Ureteral Reflux / Q000145:classification / Q000453:epidemiology / Q000601:surgery*
chemical_list: D004129:Dimethylpolysiloxanes; D012828:Silicones; C013830:baysilon