Introduction
There is controversy surrounding the treatment of ménière's
disease, a condition characterised by mystique and misunderstanding.
However, there is a definite role for surgery in a certain group of
patients.
History
In 1861, Dr Prosper Ménière, head of
The Institute for Deaf Mutes in Paris described a series of patients
with episodic vertigo, tinnitus and fluctuating hearing loss. The
first surgical treatments were undertaken in 1904 when Lake and
Milligan attempted to relieve vertigo by destroying the semi-circular
canals in the inner ear and Perry proposed intracranial division of
the vestibular (balance) nerve.
In 1923, Portmann experimentally produced balance symptoms
in fish by obliterating the endolymphatic sac, and four years later
proposed the drainage of excess fluid from the endolymphatic sac
into the mastoid as a treatment for ménière's
disease.
The surgical decision
The decision to operate on a patient with ménière's
disease often involves a consideration of the uninvolved ear. The
potential for ménière's disease to
involve both ears, in the long term, is between 20 and 34.4%. Over
90% of patients with both ears affected have better long term
hearing in the second ear. Therefore, the risk that the second
affected ear will be ultimately worse than the first is around 1%.
Patients selected for surgery in the author's practice are those who
suffer incapacitating attacks of vertigo despite maximal medical
treatment including medications, and diet and lifestyle changes.
Selection for surgery depends more on the decree of incapacity than
the frequency of attacks. Therefore, surgery is indicated in only
10-20% of patients.
The decision to proceed with surgery is a personal one based on a number
of factors. The debility suffered from recurrent attacks of vertigo
varies among patients and often relates to their general lifestyle
and expectations. A young, busy executive with frequent attacks will
request surgery much sooner than a retired, elderly patient with
occasional attacks.
The decision with regard to the type of surgery should be based on presently
available facts rather than unsubstantial evidence. Proven facts are
hard to obtain so patients and their families are advised to
carefully assess treatments and to be aware that there is no perfect
treatment for ménière's disease.
Endolymphatic Saccus Surgery (ESS)
This surgery aims to abolish vertigo but to preserve
hearing. The operation has been carried out since 1926 with many
variations which include; removal of the bone around the sac
(decompression); the insertion of a shunt or tube into the sac; and
the removal of the sac altogether.
An incision is made behind the ear and a mastoidectomy is then performed. This
involves the removal of the mastoid bone to expose the facial nerve
and semi-circular canals. The bone is then removed from around the
endolymphatic sac. The surgical treatment of the sac, including
drainage techniques or decompression, varies among different
surgeons as there is no singe established or proven technique.
Before surgery, patients frequently have hearing in the affected ear but its
usefulness may be limited by the symptoms of distortion. Following
surgery, patients may suffer from dizziness but are often well
enough to walk around after one or two days. Pain relief and
anti-nausea agents are sometimes required but patients are generally
comfortable.
The major risks of ESS include facial nerve damage, complete
hearing loss, and leakage of spinal fluid, although these are rare.
Following surgery, hearing may fluctuate or even improve in
a few cases, however in the natural course of ménière's,
the trend is a gradual decline in hearing. Successful relief of
vertigo occurs in about 60-80% of patients in the short term but
most well performed studies indicate a recurrence of symptoms over
longer periods and vestibular nerve section may be required.
Vestibular Nerve Section (VNS)
This procedure involves cutting the balance nerve supplying
the inner ear affected by ménière's disease, but preserving the
hearing nerve. The patients selected for VNS usually have residual,
sometimes fluctuating hearing loss. However, some patients have
severe hearing loss and may be selected for both vestibular
(balance) and cochlea (hearing) nerve section if tinnitus is a major
problem.
The patients who cannot undergo this type of procedure include
those with no hearing in the opposite ear and those with central
nervous system disease, such as stroke, poor health, and aged
patients. Surgery may also not be available option for patients with
hip, knee or back disorders which affect balance.
VNS is carried out by surgically dividing the balance nerve
as it passes from the brain to the inner ear. Following an incision
made behind the ear, a small bone disk is removed, giving access to
the vestibular nerve. Gentle but minimal brain retraction is
required before the nerve section.
The patient is monitored in a high dependency unit for one
night following surgery. Pain relief and anti-nausea medications are
required in the first 24-48 hours as dizziness usually occurs.
Patients are encouraged to get out of bed on the second or third day
to begin balance rehabilitation and the majority of patients are
home by the 5th to 7th day.
A marked worsening of hearing following surgery occurs in up
to 4% of cases, which is not significantly different from ESS. Most
patients experience no change but hearing will worsen over time in
the natural progression of ménière's.
There have been no cases of permanent facial weakness
following vestibular nerve section in the author's series but this
is a potential complication in all forms of ménière's disease
surgery. Other risks include leakage of spinal fluid. Severe
complications, such as meningitis or stroke have been reported, but
are extremely rare.
The disadvantage of VNS is the potential for incomplete
balance compensation. The loss of balance following surgery requires
the opposite ear to compensate. In some patients, compensation is
incomplete and patients have symptoms of veering and staggering.
Significant symptoms of this type are uncommon, and balance
physiotherapy is very useful. After surgery, more than 90% of
patients consider themselves to be more active than before.
ESS is considered a less complicated procedure than VNS but
is less successful in the abolition of acute attacks of dizziness,
especially over the long term. However, it may be considered as a
first option with VNS left in reserve.
Destructive surgery
There are a number of so-called destructive procedures
carried out to relieve vertigo in patients without hearing. These
are used when disabling attacks of vertigo occur and there is no
evidence of disease in the opposite ear.
When patients are carefully assessed before surgery,
surgical destruction of the labyrinthe almost always relieves
vertigo. The most common type of labyrinthectomy is carried out
using a similar approach to endolymphatic surgery but the entire
balance organ is removed. This type of surgery is rarely used but
may be reserved for patients in poor health who would probably not
tolerate the stresses of a longer general anaesthetic and
post-operative recovery.
Results of surgery
There is great controversy regarding the assessment and
reporting of results following surgery. The assessment of surgery
requires careful, standardised studies and long term evaluation.
This is frequently missing from many studies of ménière's disease.
The fact that surgeons are still undecided with regard to the
correct operation creates a problem for the patient. However, the
patient should be interested in knowing long-term results of the
various surgical treatments offered.
Long term studies of endolymphatic sac surgery indicate that
vertigo symptoms return over prolonged periods. Torok in 1977 showed
that endolymphatic sac surgery and many other treatments led to a
60-80% success rate of controlling vertigo. There has not been a
single report published that convincingly proves that hearing
improvement is a direct result of the surgical treatment and not
merely a result of time and the natural course of the disease.
The future
The future is bright for the understanding of ménière's
disease. Genetic mapping and engineering may find applications for
treatment. Inner ear manipulation with electrodes, lasers, and
medications may be possible in the future to alleviate or even
reverse the progress of ménière's disease.
Summary
Ménière's disease is a disabling condition. Some patients
will not respond to medical treatment and will consider surgery. The
major forms of surgical treatment include ESS and VNS. Each
procedure has its own advantages, risks, and long term results and
surgeons need to discuss these with their patients to allow an
informed decision to be made.
Ear Science Institute Australia can offer expert advice
and surgical based options for suffers of this condition. Please follow the
link below to contact our Hearing and Balance department.
For more information see:
 Rajan GP, Din S, Atlas MD (2005) Long-Term effects of the Meniett device in Meniere's Disease: the Western Australian experience. Journal of Laryngology and Otology, 119(5): 391-395.
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