Usually, hydronephrosis can disappear gradually after pyeloplasty, but there is no guarantee that it can be cured. It is recommended to go to the hospital for regular checkups to avoid infections and other conditions that may affect the effect of the surgery. Pyeloplasty is generally used to treat congenital or acquired stenosis of the renal pelvic-ureteral junction. During pyeloplasty, the surgeon needs to remove the narrowed pyeloureteral junction and the redundant renal pelvis, and then anastomose the renal pelvis to the ureter through plastic surgery, to eliminate the cause of obstruction and enlarge the renal pelvis, and the fluid retention in the kidneys will usually disappear gradually. After the operation, double-J tubes need to be left in place for support and removed after 4 weeks, so care needs to be taken to avoid infections after the operation, and the changes in the hydronephrosis should be reviewed regularly. In addition, if stones or tumors recur, they may still cause re-obstruction, so there is no guarantee that hydronephrosis can be eradicated without recurrence.