You have been through a very thorough evaluation for the dizziness - including vestibular testing, MRIs and a tilt-table test.
It is unlikely that adhesions would be causing the dizziness. I am unaware of a surgical complication that may lead to the symptoms. A side effect from the anesthesia is a possibility, but the symptoms are unlikely to last that long.
Audiometry, brainstem evoked audiometry, and electronystagmography are all tests that I would consider to further evaluate the symptoms. Brainstem evoked audiometry has a 90 to 95 percent sensitivity for detecting acoustic neuromas. Electronystagmography (ENG) tests vestibular function by using electrodes to detect either spontaneous or induced nystagmus. It has a reasonable sensitivity for vestibular disorders. You may have had some of these tests during your vestibular testing, but if not, it should be discussed.
If the neurology route is not revealing, you may want to consider a second opinion with a neurologist at a major academic medical center or an otolaryngologist.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.