The urotheliasis is a common problem encountered daily by all urologists worldwide with rates up to 13% in North America, 9% in Europe and 5% in Asia . The urotheliasis is treated by conservation, medical treatment and surgery according to many factors . Anomalies in the kidney happens due to failure in ascending , fusion, rotation or all together, horse-shoe kidney is the most common example , found in one of 400 patients . PCNL and URS are the golden standard method for stone extraction worldwide, since their introduction 1975 by Fernstrom and Johansson & Arthur Smith respectively in normal kidney .Since the development of the endourological procedures and instrument , continuous updates and upgrades have been applied ,such as enhancing the optical systems ,reducing the diameter, navigation (deflection angles) and stone fragmentation .Stone treatment in anomalous kidney is more demanding, requires more skills and training . The flexible ureterorenoscopy has some problems first the cost but this problem is being now solved by the use of disposable scopes , second the skills it requires , third the possibility of sepsis is higher . To our knowledge most of the studies in the literature are retrospective, carrying some weakness in them. There is no agreed-upon therapeutic method for treatment of stones in anomalous kidney so the investigators will evaluate the role of F-URS in a prospective study.

Inclusion Criteria:

1. Males and females age above 15 years.
2. Renal and ureteric stones either single or multiple wherever the site and site.
3. Pelvi-uretreic junction obstruction
4. Previous stented ureter.
5. Poorly functioning kidney.
6. Single functioning kidney.
7. Chronic kidney disease patient not on dialysis.
8. Previous operation in this kidney.
9. failed ESWL.

Exclusion Criteria:

1. Not fit for surgery.
2. Uncontrolled bleeding diathesis.
3. Untreated preoperative urinary tract infection (UTI).
4. non function kidney
5. skeletal abnormality