Intravesical ureteric reimplantation for primary obstructed megaureter in infants under 1 year of age

SummaryPurposeThis study aimed to assess the outcome of intravesical ureteric reimplantation for primary obstructed megaureter (POM) performed in infants under 1 year of age.Materials and methodsA retrospective cohort study was carried out of all infants undergoing intravesical ureteric reimplantation surgery for POM at two pediatric centers in the 12 years between 2003 and 2014. Outcomes were compared with those of children aged over 1 year undergoing intravesical reimplantation for POM during this period. Follow-up was until November 2015.ResultsThirty-seven megaureters in 34 infants were reimplanted, at median age 5.2 months (Table). Operative success was 97%, with one out of 34 patients (3%) requiring reoperation for recurrent ureteric obstruction. Renal preservation was high. One patient of 34 (3%), who had bilateral congenital renal dysplasia, showed evidence of decline in renal function. Five patients of 34 (15%) had postoperative urinary tract infections (UTIs). Four (13%) of those toilet trained had some symptoms of lower urinary tract dysfunction (LUTD). Three patients (9%) who had congenitally dysplastic kidneys developed hypertension. Comparatively, 14 children with POM underwent reimplantation over 1 year of age. Operative success was 86%, with two children requiring reoperation for recurrent stenosis. Both had evidence of bladder dysfunction before surgery, and thickened bladder walls noted during surgery. One of 14 (7%) had a decline in ipsilateral renal function after recurrent stenosis. Two (14%) had postoperative UTI. Three (25%) had evidence of LUTD.DiscussionThere are few data about feasibility and long-term outcomes specifically of ureteric reimplantation for POM in infancy. This is the first study to document long-term outcomes of intravesical ureteric reimplantation in infancy for POM. The recently published British Association of Paediatric Urologists consensus statement supports delaying definitive reimplantation surgery for POM that requires intervention until after 1 year of age. There is little evidence presented for this recommendation. Our study confirms the safety and feasibility of intravesical ureteric reimplantation for POM in infants under age 1, with an operative success rate of 97%, and high renal function preservation rate. UTI risk improved after surgery in children >6 months old and remained stably low in those <6 months of age. Postoperative rates of LUTD were low. Hypertension occurred in only three cases with congenital renal dysplasia.ConclusionsUreteric reimplantation in infants under 1 year of age is a safe and effective option for managing POM that requires intervention, and compares favorably with those undergoing reimplantation over 1 year of age.Table. Summary of preoperative characteristics and postoperative results.Study group (reimplanted <12 months)Comparison group (reimplanted >12 months)p (study vs. comparison group)PreoperativeTotal34 (71%)14 (29%)UTI16 (47%)11 (79%)0.047*Ipsilateral function < 45%a,b13 (42%)a8 (62%)b0.22Renal impairment (raised creatinine)1 (3%)0-Temporizing operation10 (29%)3 (21%)0.57Age at reimplantation in months, median (range)5.2 (0.1-9.2)48.1 (12.8-131.1)<0.001*Time from diagnosis to reimplantation in months, median (range)3.4 (0.1-8.6)3.8 (0.1-106)0.75PostoperativeFollow-up (years)-median (range)5.5 (1.1-12.4)4.0 (1.3-10.7)0.34Redo surgery for restenosis1 (3%)2 (14%)0.05*Decline in renal functionc1 (3%)1 (7%)Improved renal functiond2 (6%)2 (14%)0.52Stable impaired renal functiond13 (38%)6 (43%)UTIe5 (15%)2 (14%)0.05* favors infantsLUTDf4 (12%)3 (21%)0.37Hypertension3 (9%)00.25Note. Values are n (%) unless otherwise stated. LUTD = lower urinary tract dysfunction; UTI = urinary tract infection.* Significant p value (<0.05).aOf cases with a functional contralateral kidney (3 single kidneys excluded).bOf cases with Mag3 done (1 case > 12 months excluded).cIncludes newly raised creatinine, and decline in ipsilateral function in cases with normal ipsilateral function preoperatively.dOf cases with raised serum creatinine preoperatively and/or reduced ipsilateral function preoperatively.eExcludes JJ stent-associated UTI.fOf cases over toilet-training age at end of follow-up.