The value of computed tomography-urography in predicting the postoperative outcome of antenatally diagnosed pelviureteric junction obstruction

Background The natural course of pelviureteric junction (PUJ) obstruction is  variable. Of those who require surgical intervention, there is no definite reliable  preoperative predictor of the likely postoperative outcome. We evaluated the value of preoperative computed tomography (CT)-urography in predicting the  postoperative outcome.Patients and methods Ten newborns with antenatally diagnosed PUJ obstruction  were evaluated after delivery with an abdominal ultrasound, and those with a renal pelvis measuring more than 3 cm in diameter were subjected to preoperative CT-urography. The kidney size, renal pelvis size, and renal parenchyma thickness were measured and documented. All underwent open surgical Anderson-Hynes dismembered pyeloplasty. The outcome was correlated to the preoperative renal parenchymal thickness as measured by means of preoperative CT-urography.Results Ten newborns (seven male and three female) with PUJ obstruction were  operated on. Their ages at surgery ranged from 8 days to 4 months (mean= 1.75 months). Eight had PUJ obstruction on the right side and two had PUJ obstruction on the left side. The mean renal pelvis size on the affected side was 4.9 cm (3.6–6.3 cm). The mean renal parenchymal thickness was 0.57cm (0.25–1.3 cm). Four patients had a renal parenchymal thickness less than 0.5 cm, and these patients showed poor results on followup isotope scan compared with those who had a renalparenchymal thickness of more than 0.5 cm [mean= 14.9% (12–19.6%)] compared with a mean of 44.2% (33–54%).Conclusion This is a preliminary report and the number of patients in our study is small to make definite conclusions, and further studies in this regard are important. We believe that renal parenchymal thickness as measured by means of preoperative CT-urography is an important predictor of the final outcome in patients with  antenatally diagnosed hydronephrosis. Those who had a renal parenchymal thickness of 0.5 cm or less showed poor results on followup isotope scan compared with those who had a renal parenchymal thickness of more than 0.5 cm.Keywords: outcome, pelviureteric junction obstruction, pyeloplast