[Evolution of pre and postoperative renographic parameters in pyeloreteral juntion obstruction syndrome]

With the objective of observing the modifications that the postoperative Diuretic Renography (DR) curve shows and determining how the quantitative parameters of this exploration (Differential Renal Function (DRF), Peak Time (PT), Half Time (HT), descent of maximum activity at 10 min (DMA10)) can be modified, the records of 50 patients affected by unilateral pyeloureteral junction obstruction and without any other associated pathology treated between 1991 and 2001, were revised. The age of the patients was between 1 month and 12 years (average 2 years 7 months). Of the 50 patients, 31 were male and in 28 of the cases were affected on the left side. Patient selection was random. The preoperative evaluation was made using ultrasound (US), intravenous urography (IU), voiding cystourethrography (VCU), and RD. The RD technique and surgical intervention were standardized and the latter were performed by the same surgeon. Postoperative control was made with US and/or IU and RD between 6 and 18 months following surgery, even though total follow up ranged from 6 months to 10 years (average 38.24 months). In all of the cases the follow up US and/or IU results were satisfactory, even though there was residual pyelic ectasia and absence of tension. The morphology of the preoperative curves was mostly obstructive or partially obstructive without lasix response, the curves became normal in 9 cases and partially obstructive with a good response to lasix in 38. The 3 remaining cases that corresponded to the hypofunctional kidney curve did not change. The DRF did not present major variations. The postoperative PT decreased in 62% of the cases. The HT and DMA10 improved in very few cases. In conclusion, it can be said that in spite of a good surgical outcome, the patterns of the postoperative renographic curve often do not completely normalize, major variations in the postoperative DRF are not expected, and with a diminshed postoperative PT a favorable pyeloplasty outcome can be appreciated. HT and DMA10 indicate improvement when they decrease, but do not indicate that the disease has reappeared when they do not change or increase.