Stage 4 pressure ulcer

We have a resident who has had two flap procedures done over her thigh/butt area. She is bedridden. We are turning her and keeping off the area. She has now progressed from a stage 1 to 4 in about two weeks. Our surgeon is currently deciding what to do next.
My question is, has anyone ever heard of some kind of foam or filler that can be placed permanently? Something like you would use when you caulk a window??window...