The only change between post one and post three is "The" before "doctors". The "corrected" sentence has the same problems as the first one. It is awkward at best. And it is unnatural. Use "difficult" if you insist. Otherwise, I urge you to use my sentence. (No. It's not because it would hurt my feelings if you didn't.)
Note that 'T.B.' should be 'TB'. Tuberculosis (TB) is one word. Terrabyte also shares 'TB'.
If you abbreviated 'Terre Blanche', it would be 'T.B.', because it's two words.