I am glad that they put a nephrostomy, which would protect your kidney from a likely damage and give us a breather to plan future course of action. It would be ideal to be under the care of a good urologist. If no test for kidney function (Intravenous Pyelogram [IVP] or CT scan) was done before your hysterectomy then it would be necessary to know if kidney was blocked because of some stone before the surgery or it was as a result of some surgical problem. They will put some dye in your kidney through nephrostomy to know the exact site of blockage before they plan the treatment.