Found out mom has fistula - constant feces running out- what is this?

Yes it is called anal fistula. It is essentially another opening from the rectum through to the outside skin. It is formed when an anal gland forms an abscess, which in turn has burst through the skin. It forms another tube like opening from which feces may leak.

Depending on the site of the fistula, a doctor may do a procedure to correct this. You should speak further with her doctor to see if treatment would be indicated based on her condition. Definately more information is needed.

I hope this was helpful. Good luck and hugs.
HB