Another widely used treatment for the cure and release of kidney stones is extracorporeal shock wave lithotripsy or ESWL. The procedure is similar to the electrohydraulic lithotripsy procedure where the end goal is to break-down the kidney stone so that it can pass through the urethra, but with this particular treatment ESWL uses highly focused impulses projected from outside of the body to crush and annihilate the kidney stones. The procedure will typically reduce the kidney stones to sand-like granules that will allow a patient to easily pass them through the urine flow. If the stones are very large, several or more ESWL treatments might be needed. The procedure, while effective, should not be administered in pregnant women.