WHAT IMAGING STUDIES ARE NECESSARY TO DETERMINE OUTCOME AFTER URETERONEOCYSTOSTOMY

Purpose: After ureteroneocystostomy we have performed renal ultrasonog raphy within the first 3 months to exclude hydronephrosis, voiding cys tography after 3 months to exclude vesicoureteral reflux and subsequen t ultrasonography to monitor the upper tracts. This study attempted to determine those patients at risk for hydronephrosis or recurrent vesi coureteral reflux, Materials and Methods: We studied the: records of p atients who underwent ureteroneocystostomy in the last decade at our i nstitutions to find the incidence and degree of preoperative and posto perative 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 ev aluated for risk factors that differentiated them from others. Results : Excluding patients with neuropathic bladder or ureterocele, 167 unde rwent 278 ureteroneocystostomies at a mean followup of 26.5 months, Pe rsistent vesicoureteral reflux was noted in 4 kidneys (1.4%) and contr alateral reflux developed in 3 of the 48 cases (6.3%) of unilateral ur eteroneocystostomy. There was no statistical difference in success rat es among cross-trigonal, ureteral advancement or extravesical techniqu es. New onset mild hydronephrosis in 13 kidneys (4.7%) at the initial followup study (mean 1.6 months) completely resolved in 12 and remaine d mild in 1. No patient had progression of existing hydronephrosis and 1 had recurrent vesicoureteral reflux after initial negative cystogra phy. Risk factors for postoperative reflux or hydronephrosis were preo perative dysfunctional voiding, preoperative hydronephrosis or scarrin g on sonography and postoperative urinary tract infection. None of the 88 patients without these risk factors had postoperative hydronephros is or reflux. All patients with persistent, contralateral or recurrent reflux were selected using these criteria (p <0.003). Conclusions: Co mplication rates after nontapered ureteroneocystostomy in children wit hout neuropathic bladder are quite low, Mild postoperative hydronephro sis was not clinically significant in our patients, Children with abno rmal preoperative ultrasound or dysfunctional voiding are identified a s a high risk group for postoperative hydronephrosis or recurrent refl ux. All other patients received lit-tie benefit from postoperative ima ging, suggesting that further evaluation of this group is necessary on ly in the presence of a postoperative urinary tract infection.