Timothy C. Hain,
Last edited: 1/2003. Please read our disclaimer.
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There are few times when surgery is appropriate for dizziness. Most disorders either can be treated effectively medically, or there is no treatment at all. Surgical treatments that are available can be broken down innto corrective and destructive types.
Unfortunately, there are relatively few instances where surgery can be viewed as a corrective procedure for vertigo. Interestingly, in all cases where there is a proposed corrective surgery, either the process of diagnosis is controversial, or the treatment itself is controversial. This suggests that caution is appropriate when a corrective procedure is proposed.
|Figure 1. Round window fistula. An opening in the round window allows perilymph to leak out into the middle ear. In this artist's depiction, for clarity, bone is not shown between the middle and inner ears. While it is difficult to be sure, it seems likely that in most cases there is only a small oozing of fluid between the perilymphatic space and the air-filled middle ear.|
In perilymph fistula, surgery may be used to plug a leak in the inner ear. Both the diagnostic process and the treatment is somewhat controversial. Conventional treatment involves exploration of the ear, and placement of a "patch" over the window areas. Occasionally placement of a tube in the ear drum may be effective. Medical treatment is poor for PLF and in most cases the patient will have to decide between living with the symptoms or proceeding with surgery.
|Figure 2. Ventilation tube placed in ear drum. By providing an artificial opening in the ear drum, pressure fluctuations between the middle ear and outside world can be avoided. This is sometimes helpful in treatment of perilymph fistula.|
Recently a new type of fistula has been described involving dehiscence of the superior canal. Whether or not surgery will be effective for this syndrome is presently uncertain. Attempts have been made to treat it using patchs, but sometimes the result is catastrophic to hearing. Canal plugging might be the best treatment for this disorder.
It is our opinion that PLF surgical treatment varies greatly across the country and sometimes even within the same metropolitan area. We advise caution and a second opinion, best obtained from outside the local medical community, when considering surgical treatment for PLF. Most otologic surgeons in the United States perform only about 5 of the "patching" operations/year. In our view, this reflects a reasonable frequency of surgery for the usual local otology practice. A higher frequency of surgery than this suggests that either the surgeon is having fistula cases referred in to him/her from outlying areas or that he/she is unusually aggressive. A lower frequency of surgery than this may mean that the surgeon is more conservative as well as less experienced than the majority of his/her associates doing otology.
In the microvascular compression syndrome, surgery may be used to move a blood vessel off of the vestibular nerve. Medical treatment is uncertain for MVC syndrome, as it is very difficult to establish the diagnosis. This surgery is difficult and is best done by an experienced neurosurgeon.
Like the case with fistula surgery, there is considerable controversy about diagnosis and treatment and we would advise caution and judicious second opinions, ideally from outside the local medical community, before proceeding with such surgery.
In Meniere's disease, shunt surgery is intended to improve inner ear plumbing. There is controversy primarily in regard to whether this procedure is effective or a placebo (or worse). The consensus at this writing (4/1999), is that shunt surgery is modestly effective for several years. It compares unfavorably with transtympanic gentamicin (see destructive procedures). It may be roughly equivalent to medical treatment (which isn't very good either).
All treatments for Meniere's must be compared with the natural history of Meniere's, where 60% of patients are in remission by 6 months. The most common type of shunt surgery consists of putting in a small tube or plastic sheet into the endolymphatic sac. Another procedure is termed "endolymphatic sac enhancement", a procedure which includes "lateral sinus decompression" (Sajjadi, Paparella and Williams, 1998). Shunt surgery is generally felt to be ineffective when viewed over 5 years although it may improve the situation for 2 years. The most disturbing report came out of the "Danish Sham Study", where individuals treated with placebo fared better than those with shunts. There is also good evidence that tubes placed in the sac close up by 4 years. Nevertheless, it is possible that procedures that either destroy the sac or remove surrounding bone through which lymphocytes migrate into the sac might alter its immune function enough to cause a remission of Meniere's disease. To summarize, at this writing, shunt surgery may have some short term benefit, and the mechanism of the benefit may relate to immune modulation.
It is our view that shunt surgery is presently overutilized. We think that it will be gradually replaced by transtympanic gentamicin (see destructive section), or more effective medical treatments for Menieres disease.
Chronic ear disease includes a wide range of ear disorders including chronic otitis media, chronic mastoiditis, tympanosclerosis and cholesteral granuloma. Processes that cause vertigo are those that can involve the inner ear and are mainly mastoiditis and cholesteatoma. Most treatments involve opening up the middle ear space to allow it to drain and an infection to resolve. Procedures include atticotomy (removal of the lateral epitympanic wall (scutum)), as well as several types of mastoidectomy.
These are designed to eliminate vertigo, possibly sacrificing hearing. These procedures are appropriate for consideration when medical treatment and vestibular rehabilitation has failed to control vertigo symptoms. By medical treatment we mean a vigorous and informed regimen of treatment supervised by a physician who is familiar with dizziness and its pharmacology. Indications are generally much clearer for destructive treatment than for corrective treatments, and results are better. Vestibular Rehabilitation therapy is appropriate in all patients after destructive treatment.
|Figure 3. Gentamicin injection for Meniere's disease.|
For Meniere's disease, destructive procedures are associated with better control of vertigo than shunt surgery, showing good control in over 90% of patients followed for 5 or more years. The vestibular nerve may be sectioned via the middle fossa, retrolabyrinthine, and retrosigmoid approaches, with similar efficacy. Nerve section can fail due to a variety of reasons -- the nerve may be incompletely sectioned, it may regrow, a neuroma may form, or the diagnosis might have been wrong.
Transtympanic gentamicin treatment is a rapidly growing outpatient procedure that offers similar results to vestibular nerve section but with much less risk. Labyrinthectomy is appropriate for patients in whom there is no hearing in the ear which is causing vertigo and offers excellent control of vertigo, with less complications than nerve section. Recurrent vertigo is less much less likely after labyrinthectomy than nerve section (Badke et al, 2002).
Destructive treatment is generally entered into with much less enthusiasm when there is evidence for bilateral Meniere's. As about 50% of persons with Meniere's eventually develop bilateral Menieres, this excludes a substantial proportion of the population with this disorder.
It is our view that transtympanic gentamicin treatment, at the present writing, is underutilized. It is a very effective treatment with little risk. It is our view that labyrinthectomy and vestibular nerve section surgery are presently being overutilized, and as time goes on, they will largely be replaced by gentamicin treatment.
Removal of the acoustic tumor in acoustic neuroma surgery generally results in elimination of vertigo, as the nerve is usually sectioned. Other destructive treatments of acoustics include gamma knife (radiation) treatment.
It is our view that acoustic neuroma surgery is presently generally being done for the correct reasons and by very well trained and informed surgeons.
In individuals who fail fistula surgery (for perilymph fistula), a destructive treatment also seems reasonable when symptoms are disabling. Here options might reasonably include a vestibular nerve section or labyrinthectomy, should hearing already be severely impaired. It is rare to encounter a situation where destructive surgery is contemplated for PLF.
|Figure 4. Posterior canal plugging for Benign Paroxysmal Positional Vertigo (BPPV).|
For Benign Paroxysmal Positional Vertigo, selective posterior canal plugging offers a reasonable surgical approach to intractable symptoms. Singular neurectomy, an older procedure, is less popular because it produces hearing loss in 7-17% of patients and fails in 8-12%. Vestibular nerve section seems unreasonably aggressive for BPPV, as does transtympanic gentamicin.
Destructive treatments might also be considered for variant BPPV such as cupulolithiasis, as well as BPPV involving other canals than the posterior canal. Cupulolithiasis is the most difficult form of BPPV to manage and therefore might be the most reasonable one in which a destructive treatment should be considered.
It is our view that destructive treatments for BPPV are being rarely used, and when they are, generally the indications are appropriate and the results are good.
We generally do not think that destructive treatments are appropriate for vestibular neuritis, but there are occasional exceptions, when medical treatment fails and symptoms are severe. We also do not feel that destructive treatments are indicated when the diagnosis is unclear. Destructive treatments are risky for continued vertigo when there is impairment of central adaptation, such as in seniors and in people with pre-existing cerebellar problems.
Figures are courtesy of Northwestern University.