Whilst under general anaesthetic a cystoscope is used to introduce a guide wire into the affected ureter. The cystoscope is removed and a ureteroscope is passed through the urethra and bladder into the ureter, using the guide wire as a guide. When the ureter is found to be normal a ureteric access sheath is introduced over the guidewire. the flexible ureterorenoscope is then passed through the access sheath into the kidney. The ureterorenoscope is guided around the kidney visually, helped by Xray image intensifier. It can be used to diagnose tumours or treat stones; when a stone is visualised a laser fibre is introduced through the ureteroscope to touch the stone. Laser energy then fragments and vaporises the stones. Fragments can be removed by using a basket. A ureteric stent might be inserted into the ureter at the end of the procedure.