How did men survive this?

[Anomalocaris]

I almost passed out just from reading this and I’m not even a guy.

“In the 19th century, to break a stone from their bladder, men had to pass a nail through their penis and then use a hammer to break it into pieces small enough to pass through their urethra. The was performed without anesthesia until around 1846.”

What happens if the bladder stone is not directly above the urethra opening of the bladder?  Wouldn’t this procedure risk rupturing the bladder?