Hmmm...the thing is, you can't be 100% certain that you won't have any more problems, so I don't get how any doctor would refuse that. But what does the university specifically mean by "documented"? If you have a diagnosis, I think they can request copies of medical reports, but they can't deny the diagnosis. Also, did you notify your university prior to the problems you recently had? If they were aware of it, you probably have at least some recourse in that you probably could have succeeded if you had some assistance. You are protected under the ADA, but I don't really know what qualifications there are. You can read up on it or consult with a civil rights attorney.