I don't think this is altered. I do not think you are seeing the end of the support post in the stretcher. I think it's a gap in the material and a cutout/rivet in the post.
Secondly, the focus seems to match on the casualty himself and the surrounding materials. I do think the stretcher itself is pretty ratty and busted up.
I do suspect this is a staged photo, but aren't most from this region suspect of that?
I agree that this is staged but not altered.