If the stones are in the bladder there is less urgency to remove them. 1 cm might pass through the urethra, but they often do get stuck and then you need to have a doctor put in a catheter or more complex probe to remove it or blast it with ultrasound. Other stones can remain a long time in the prostate ....or I think the kidneys. On Monday I just had many stones removed: no flesh cutting, just the catheter type probe with camera, cutter, holder for stones, etc. They break up the stones and cut out prostate tissue and let it drain out. I'm still weak and tired but my urologic problems should be fixed now.