What a tough position to be in. I would be concerned about an episiotomy providing a weak point and so you would get further tearing from the episiotomy cut.

There are techniques and positions that can help protect the perenium, e.g a warm face washer held on the area, no coached pushing. I would want to use these techniques during labour, even if you decide to go with the episiotomy as well.

Would there be extra difficulties with having a c section and healing due to your condition?

take care