Refluxing megaureter in infancy - The significance of differentiation from primary high grade VUR

(Background) Recent advance of perinatal ultrasound screening and/or physician's awareness of renal damage from recurrent pyelonephritis has brought about the increasing number of infants with primary vesicoureteral reflux (VUR) including refluxing megaureter which should be conceptually differentiated from simple high grade VUR. We evaluated the clinical outcome of infants diagnosed with refluxing megaureter. (Patients and Methods) We retrospectively reviewed the clinical records of 15 infants (17 ureters) diagnosed as refluxing megaureter (max caliber ≥ 10mm) at our institution from 1988 to 1997. We compared the clinical outcome of refluxing megaureter with that of high grade VUR. (Results) Patients were 13boys and 2girls. Megaureter was unilateral in 13 patients and bilateral in 2. Fourteen infants (93.3%) presented with febrile urinary tract infection (UTI) . The diameter of megaureter was 10~21mm (average: 13.6 ± 4.0mm) at excretory urogram. Nine of 15 infants (60.0%) had breakthrough urinary infection. Its incidence was significantly higher than that of high grade VUR (21.3%) (p = 0.02). In 13 cases surgical treatments were performed, however 2 cases (max caliber: 16mm, 21mm) by Politano-Leadbetter or Paquin procedure required re- ureteroneocystostomy by Psoas-hitch procedure because of persistent reflux and recurrent UTI. On the other hand no patient required re- ureteroneocystostomy in high grade VUR. (Conclusion) It is important to differentiate refluxing megaureter from high grade VUR due to high incidence of breakthrough UTI. Ureteral remodeling and/or Psoas-hitch procedure are strongly recommended for adequate length of submucosal tunnel in refluxing megaureter.