system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Considering that Kidney Stones are notoriously painful (as well as common), why is it so difficult to develop a painless method of extraction?

Furthermore, why can't they use some form of anesthesia?
gpt
The stones are inside part the kidney, which is a very delicate organ with a great deal of major blood vessels going into and out of it.

It's a dangerous area to mess around with, with the amount of blood moving through it.

Nicking an artery can lead to some serious damage.

Additionally; once they leave the kidney they have to pass through a muscular tube which conveys urine down to the bladder. That's something you really want to avoid the damage surgery will do to it, as scar tissue is potentially dangerous if it blocks the tube.

I can't answer the anaesthesia part, though!