[Hydronephrosis due to abnormality of the pelvi-ureteric junction (P.U.J.). Based upon 162 cases representing 181 P.U.J. syndromes (author's transl)].

The authors present a retrospective analysis over a period of 15 years with a minimum follow-up of 18 months. 34 patients were under the age of 10. In terms of diagnosis and therapeutic indications, intravenous urography remains the basic examination. Two other investigations are extremely valuable: retrograde cystography, in particular in the child, to seek associated vesico-renal reflux and echography, in particular as a harmless means of regular surveillance, both for hydronephroses which have been operated upon and those which have not. Seventy five patients did not undergo surgery and only 25 could be regularly followed up. In contrast to widely accepted ideas, 4 worsened considerably. Only 13 nephrectomies were performed at the outset, including six partial because of double/bifid kidney/ureter. There were thus only 6.7% of total nephrectomies at the outset. Despite this resolutely conservative attitude, there was only one secondary nephrectomy for lithiasis despite a good result of P.U.J. plasty. Renal biopsies confirmed that the renal parenchyma was usually normal, even in the presence of very marked hydronephrosis, in the absence of infection. The results of conservative surgery were good in 83% of cases, thereby justifying the resolutely conservative attitude of the authors. 92 plasties of the pelvi-ureteric junction revealed the rarity (15.2%) of hydronephrosis due to abnormal polar vessel and the relative prevalence (29.5%) of hypoplasia of the first few millimetres of the lumbar ureter distal to the P.U.J.