Otosclerosis is a common cause of hearing
impairment. (The word otosclerosis can be broken into its two medical
words: "oto" for ear, and "sclerosis" meaning hardening.) Approximately
5% of all people with hearing impairment have otosclerosis. The
condition is hereditary. That is, members of a family pass the
condition down to their children. Although otosclerosis is hereditary,
this does not necessarily mean that the children of patients with
otosclerosis will develop the condition.
Hearing Impairment from Otosclerosis
Otosclerosis is an abnormal growth of bone. The abnormal bone growth of otosclerosis
may spread to the inner ear, stapes (the third ear bone), or to both
of these areas.
When otosclerosis spreads to the inner ear a sensorineural hearing
impairment (see How We Hear) may result
due to interference with hearing nerve function. Once nerve impairment
develops it is permanent. Very rarely does otosclerosis alone cause
total deafness. In selected cases medications may be prescribed
in an attempt to prevent further nerve impairment.
It is more common for otosclerosis to surround the stapes bone than
to damage the inner ear. The abnormal otosclerotic bone hardens
around the stapes and eventually stops the movement of the stapes.
The immobile stapes cannot carry sound vibrations to the inner
ear. Therefore a conductive hearing loss develops.
The degree of sensorineural and/or conductive hearing impairment can
be determined only by careful hearing tests.
There is no local treatment to the ear itself or any medication that
will improve the hearing in persons with otosclerosis. In some cases,
medication may prevent further nerve hearing loss.
A medication known as Florical (8.3mg sodium fluoride and 364mg of
calcium carbonate) is sometimes prescribed to prevent further nerve
hearing loss. This medication slows down the growth and may eventually
stop the growth of otosclerosis.
The optimal dosage of Florical is 1 capsule every 12 hours with meals.
Ideally, this medication should be taken for two years. After two
years, the hearing level, the degree of tinnitus, and the severity
of imbalance are reevaluated. If these conditions have stabilized,
the Florical may be discontinued or the dosage reduced. Florical
should be avoided during pregnancy.
The stapes operation (stapedectomy)
is recommended for patients with otosclerosis who are candidates
for surgery. This operation is performed under local or general
anesthesia with the use of laser and microscopic techniques. Most
patients go home the same day (outpatient procedure). Convalescence
at home for about a week or so is recommended. Nearly 90% of these
operations are successful in improving the conductive hearing loss.