Well corruption basically means data has been altered. There really isn't a way to know what that data was prior to being corrupted. A backup is the best way to resolve this kind of problem. Office files are just structured data, so it's certainly possible to build a blank project and extract the components from the corrupt file I don't image that would be very easy and very time consuming. For example you can rename a word file from .docx to .zip and extract it's content with 7zip