[Urodynamic study of obstruction induced by vesicoureteral reflux surgery with submucosal advance in beagle female dogs].

The treatment of veslcoureteric reflux by submucosal advancement is effective in human clinical practice on nondilated refluxing ureters, with a low morbidity. In contrast, the results of this technique in the presence of concomitant disease such as megaureter appear to be less favourable and could be due to obstruction induced by the reflux surgery. The objective of this study was to evaluate the urodynamic modifications of ureterovesical reimplantation in 10 female Beagle dogs. Left ureterovesical reimplantation by submucosal ureteric advancement was performed in each animal which constituted its own control. The morphological results were assessed by intravenous urography and retrograde cystography. The urodynamic study was conducted during another surgical operation performed, on average, around the 18th postoperative week. A 6F two-channel probe was inserted on each ureter: while a pump delivered a constant infusion (2 then 5 ml/min) into one channel, the ureteric pressure was measured by the other channel. The bladder pressure was recorded by a bladder catheter. For each infusion rate, the increased pressure in the reimplanted ureter was compared to that measured in the control ureter, as a function of the bladder pressure. The subsequent morphological evaluation demonstrated the absence of any repercussions on the upper urinary tract and the absence of vesicoureteric reflux and paraureteric diverticulum. An initial increase in the basal ureteric pressure was observed at the beginning of the infusion and was significantly higher in the operated ureter than in the control ureter (for an infusion rate of 2 then 5 ml/min, p = 0.0008 and 0.00029, respectively). The mean ureteric pressures increased in parallel, but those recorded in the reimplanted ureter were significantly higher than those recorded in the control ureter (p < 0.01). Ureteric pressure peaks were only recorded on the reimplanted left ureter at an infusion rate of 2 ml/min. These results suggest that, in this experimental model, the resistance to passive flow was higher in the reimplanted ureterovesical junction than in the control ureterovesical junction.