COMPARISON OF ACUCISE ENDOPYELOTOMY AND ENDOBALLOON RUPTURE FOR MANAGEMENT OF SECONDARY PROXIMAL URETERAL STRICTURE IN THE PORCINE MODEL

At this point in time, endopyelotomy is first-line therapy for both pr imary and secondary adult ureteropelvic junction obstruction (UPJO) in many medical centers. However, the potential, albeit small, for signi ficant bleeding with any endoincision of the UPJ has sparked interest in the simple, less morbid technique of endoballoon rupture. To date, no comparative data are available on the effectiveness of these two te chniques. Thirty female minipigs were randomized to cutting balloon (A cucise) endopyelotomy (AEP) (N = 13), endoballoon rupture (EER) (N 13) , or a control arm (N = 4). Following baseline retrograde pyelogram (R PG) and diuretic renogram (DRG), a secondary proximal ureteral strictu re was created by laparoscopic ligation of the UPJ. After 8 weeks, AEP or EER was performed in each of the study pigs. In 16 pigs (8 AEP, 8 EER), a 7F 22-cm ureteral stent was placed (chronic arm). After 6 week s, the stent was removed, and a second RPG and DRG were performed. Thr ee months post-treatment, after RPG and DRG, the renal units were harv ested, and histologic sections of the affected UPJ, contralateral norm al ureter, and ipsilateral kidney were examined. Ten pigs (5 AEP, 5 EE R) underwent harvest immediately after treatment (acute arm). The four control animals remained untreated. At 8 weeks, all minipigs had obst ructive findings on RPG and DRG. All UPJs could be treated but one, wh ich had an impassable stricture; there were no perioperative complicat ions. In the acute arm, all UPJs were patent, All five AEP ureters had evidence of an uneven cut and cautery effect. Of the EER ureters, two had smooth tears and three had ragged tears, and none had evidence of cautery effect. In the chronic arm, 3 months after either AEP or EER, all minipigs had a patent UPJ, yet only 5 of 16 had an improved t(1/2 ) by DRG. Histologic sections of the affected UPJs from 20 minipigs in the chronic arm (8 AEP, 8 EER, 4 controls) were indistinguishable amo ng the three groups; each revealed significant periureteral fibrosis a nd chronic inflammation with a mainly unremarkable muscular layer. How ever, histologic sections of 25 treated kidneys, including both acute and chronic animals (13 AEP, 12 EER), revealed endstage renal disease (N = 10), chronic inflammatory changes (N = 7), or normal tissue (N = 8). Again, there was no trend favoring either AEP and EER. In summary, in this laboratory study, we could detect no difference in outcome be tween an incisional endopyelotomy and an endoballoon rupture for treat ing secondary UPJO.