Remember, proponents of the vascular theory are seeking a smoking gun: a direct linkage between some vascular event such as ischemia or infarction and deﬁnite changes associated with hearing loss. Changes in the temporal bones, such as labyrinthine ossiﬁcation, if consistently found in patients with SSNHL, would be such a smoking gun. Saumil N. Merchant, ., and his colleagues at my institution, the Massachusetts Eye and Ear Inﬁrmary, recently reviewed specimens of temporal bone in the Inﬁrmary’s collection from 17 cases of SSNHL. 3 Only one specimen showed any evidence of new bone formation—the vascular theorists’ hoped-for smoking gun. Another strike against the vascular theory is the relationship of SSNHL prognosis to the site of cochlear injury. The cochlear artery runs from the base of cochlea, where high-frequency sounds are detected, to the apex, where low-frequency sounds are detected. Since there is no collateral blood supply to the cochlear apex, blockage of the cochlear artery should cause the most severe damage to low-frequency hearing. But clinical reports show exactly the opposite: SSNHL affecting low-frequency hearing of the cochlear apex actually has a better prognosis than SSNHL affecting high-frequency hearing in the cochlear base. Another difﬁculty is that if the labyrinthine artery itself were affected by some vascular event, both auditory and balance functions should be impaired, but only a few patients with SSNHL experience severe or sustained vertigo.
The remaining two procedures, vetibular neurectomy and labyrinthectomy, are ways of eliminating the balance function of the faulty ear. It is known that individuals will function better with one normal balance system than with one normal and one faulty system. The labyrinthectomy is a procedure in which the mastoid bone is removed and the inner ear is eliminated. This procedure is for patients that have lost usable hearing in the affected ear, as it entails removing all function of the inner ear, including hearing and balance. The change from having two balance systems to having one balance system alone does require a recovery or "compensation" period. It takes the brain a period of weeks to figure out that only one system is active and that it is no longer receiving information from the faulty system which it had come to expect. The second procedure, the vestibular neurectomy, is a good option if the hearing is good in the ear with the failing balance system. In this surgical procedure, the balance nerve (vestibular nerve) is cut between the inner ear and the brain. The inner ear is completely preserved but the faulty balance information is not able to reach the brain and cause the vertigo. Like the labyrinthectomy, this procedure requires a recovery period while the brain "figures out" the new situation.
It should be noted that surgical treatment is primarily used to prevent attacks of vertigo. These procedures have not been demonstrated to affect the long-term progression of sensorineural hearing loss associated with Meniere’s Disease. The severity of your symptoms will also help determine the type of treatment you will receive. For example, if one is having falling attacks not controlled with medical management, then there will be a greater need for a definitive treatment such as intratympanic therapy (corticosteroid or gentamicin) or surgical control of vertigo.