I have actually had leech treatment believe it or not.
Several years ago I sliced the pinky of my left hand clean through to the knuckle from the back side.
It required microsurgery to re-connect the severed portion including the blood vessels, tendons, etc.
Part of the follow up treament was using leeches to ensure blood flow to the reconnected finger end.
Heh on a funny side note my insurance tried to deny the claim seeing as they saw the loss of a pinky fingure was not in their mind detremental to my work. I only had to ask one question..."Do you type at your job?"