Functional results of pyeloplasty in patients with ante-natally diagnosed pelvi-ureteric junction obstruction

To assess the outcome after pyeloplasty in children with an ante-natal diagnosis of hydronephrosis, shown on post-natal renography to be due to pelvi-ureteric junction (PUJ) obstruction, and in particular to review the outcome of those who had initially been managed expectantly.

Between 1984 and 1995, 321 patients were diagnosed as having PUJ obstruction, after investigating ante-natal hydronephrosis. Of these, 47 had undergone pyeloplasty and also had a normal contralateral kidney; 26 patients had early pyeloplasty because of impaired function and 21 underwent surgery after a period of expectant management. Renal function was assessed renographically before and at least one year after surgery.

Relative renal function was stabilized in those patients who underwent early pyeloplasty (mean differential function 28.1% before and 32.7% after surgery). In patients who underwent pyeloplasty after a period of expectant management, the mean relative function decreased from 44.8% initially to 30.5% before surgery; this recovered to 37.5% at the post-operative reassessment, representing a statistically significant loss of function (P < 0.01).

In patients born with PUJ obstruction and impaired renal function, pyeloplasty failed to significantly improve function. Possibly because of cortical loss. In patients with ante-natal PUJ obstruction managed expectantly there is a small but significant risk of a modest loss of renal function.