[livingwith]

my son has had many stones blasted but we finally got the answer to his stone problem. his urether was too small at one end and not working right. The doctor cut and reattached it so the urine is not stagnant in his kidney.
We are hopeful this is the end....Read the full article

[UroDoc]

It is called a UPJ obstruction and is often congenital, sounds like fixing it should solve the problem.