IMPACT OF THE PELVICALICEAL SIZE ON THE S UCCESS RATE OF ENDOPYELOTOMY

In primary pelviureteric junction obstruction with a large pelvicalice al system, urine flow is impaired not only by intrinsic obstruction, b ut also by ineffective pressure development (Laplace's principle) and perhaps by vessels or fibrous bands. As endopyelotomy only corrects th e intrinsic factor, we examined the effect of pelvicaliceal size on th e results of endopyelotomy. In a prospective study, 35 patients with p rimary pelviureteric junction obstruction were treated by endopyelotom y. The volume of the pelvicaliceal system was estimated preoperatively and correlated with the outcome. After endopyelotomy, all patients we re stented with a ureteric catheter for 6 weeks. At 6 weeks 27/35 pati ents (77%) had free drainage of urine into the bladder. Of patients wi th pelvicaliceal volumes of 10-40 ml and 41-65 ml, 17 of 18 (94%) had a successful result, whereas in patients with pelvicaliceal volumes of 66-90 mi and those greater than 90 ml, only 10 of 17 (59%) were succe ssful. This difference in success rate associated with pelvicaliceal v olume was statistically significant (p = 0.018). After 6 months follow -up there were no relapses. Endopyelotomy is a safe and successful tec hnique, but large preoperative pelvicaliceal volume is associated with a reduced success rate.