This treatment is frequently used for the treatment of kidney stones which are less than 2cm in size. It is less frequently used for stones in the upper ureter (just below the kidney). Extracorporeal Shockwave Lithotripsy, usually referred to as ESWL, is not usually used for stones in the mid and lower ureter or for stones causing pain and obstruction.

ESWL is a procedure which breaks kidney stones by focusing sound waves onto the stone. These sound waves are audible and are not ultrasound (which cannot be heard). The sound waves pass from the ESWL machine through the skin and muscles, through the outside of the kidney onto the stone. The energy from the focused sound waves is very high – enough to break many stones.