This comment  intrigued me; I recognize that the paper addresses a UK procedural problem, but the management of the obstructive ureteric calculus is of general interest. Logically the obstructed ureteric calculus requires ureteroscopy and lithotripsy, as these techniques offer the opportunity of a ‘one-off’ solution . Percutaneous nephrostomy (PCN) relieves the obstruction but commits to a second definitive procedure. Occasionally ureteroscopy is not the straightforward procedure one expects. Particular difficulty is encountered with the impacted, fully obstructed, distal-third ureteric calculus. A useful tip I have used is to introduce the 7.5 F Wolf ureteroscope up to the point of obstruction under direct vision; the ureteroscope nor guidewire go no further. I then introduce the 0.8 mm Swiss Lithoclast probe and this is vibrated under direct vision at multiple-pulse mode with the water jet flowing. The probe is not advanced . This technique opens the ureter and the lower end of the calculus becomes visible. Fragmentation can safely commence. I suppose that the vibrating probe disperses the oedema fluid and breaks down the peri-ureteric fibrosis that fixes the ureter . In practice therefore we can fragment almost all ureteric calculi ureteroscopically .