In this method, which is used in the treatment of kidney stones of 2 cm and smaller, a thin instrument (flexible ureterorenoscopy) with a length of 70 cm, with a light source, and imaged with a fibre optic system is used. The stones are broken by using laser power sources by entering the kidney through the access sheath called 'Access sheat'. The broken stone pieces are expected to be divided into small millimetric fragments and fall on their own. If there is a suspicious mass or appearance causing obstruction, a biopsy is taken or endoscopic scraping (resection) can be performed. At the end of the operation, a ureteral catheter or a double-J catheter (a soft plastic thin tube with one end in the kidney and the other in the bladder) is inserted into the ureter. The surgery may take approximately 1 hour.