Xu G, et al. – In order to observe the potential recovery of renal morphology and DRF after successful pyeloplasty, the outcomes in patients who were <1 year old and had hydronephrosis with SFU grade 3–4 PUJ obstruction, were compared. This study suggested significant improvement in DRF after pyeloplasty for patients with an initial DRF from 30 to ≤35%. Data depicted the greater probability of achieving the normal renal function in patients with an initial DRF from 35 to ≤40%. A marginal probability of achieving a normal value was noticed in patients with severely impaired initial renal function.