Reply to "help interpreting again please"

Yep. The study showed contrast material leaking to the presacral space. This is the area between your pouch and the lower spine, pretty common area for a leak. That was where I had my abscess way back when (but no fistula, as the leak sealed pretty quickly on its own). Yours could easily been there since your original peritonitis, but just not diagnosed.

The dilation of the pouch sounds like normal pouch "stretching." But, it does appear that you also have an anal stricture. This may have been the reason for the fistula.

You probably already know that fistulas with abscess pockets can be one of the most difficult complications to deal with. Long standing ones are usually opened so that the abscess pocket actually becomes part of the pouch itself, rather than trying to close or remove it.

Jan