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

Objective: 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.

Patients And Methods: 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.

Results: 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).

Conclusion: 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.