Clinical and experimental evaluation of ureteric dilatation.

The present study was designed to evaluate the effect of ureteric dilatation (performed as a prelude to rigid ureteroscopy) on the vesicoureteric mechanism in experimental animals and man. Through a vesicotomy the left ureteric orifices of 10 anaesthetised male New Zealand White rabbits were dilated approximately 3-fold (to 4-5F) using Seldinger wires and gradated cannulae. Serial intravenous urograms and histological examination of the excised vesicoureteric junctions were performed at intervals of 2 weeks. Histologically, acute inflammatory changes were noted at 24 h, but at 2 to 8 weeks the histological appearances were normal. Radiologically, transient upper tract dilatation was noted in three animals. In 10 patients, intravenous urograms and micturating cystograms were performed 3 months after ureteric dilatation to 14F (prior to ureteroscopy). One asymptomatic patient had grade 1 vesicoureteric reflux but no other radiological abnormalities were found. It is concluded that ureteric dilatation is a safe procedure which merits reassessment as a urological technique.