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| EAR DISORDERS & TREATMENTS > Otosclerosis |
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Introduction
Otosclerosis is a relatively common cause of hearing loss and may run in families.
The disorder is a condition affecting the bones of the middle ear,
and is only known to effect humans. The hearing loss caused by
otosclerosis is often treatable by surgery.
The normal ear and hearing loss
The ear is divided into the external, middle and inner ear. Sound waves pass into the
external ear and vibrate the eardrum. The movements
of the eardrum are transmitted into the middle ear by three small
bones. These are the malleus (hammer), incus (anvil) and the stapes
(stirrup). The bones transform sound waves into vibrations of the
inner ear fluids, turning sound waves into electrical impulses.
The external and middle ear act as conductors of sound and the inner
ear is the receiver. A disorder of the external or middle ear causes
a conductive hearing loss. A problem involving the inner ear causes
a sensorineural or nerve hearing loss. Otosclerosis often causes a
combination of these hearing losses but the dominant component is
conductive.
Otosclerosis
Otosclerosis causes tiny
areas of bone to harden. These hardened areas may affect the stapes
bone, inner ear or both of these areas. Pure inner ear otosclerosis
is rare. Otosclerosis typically begins in the teenage years or third
decade of life. The condition is reported more frequently in females
and usually, but not always, involves both ears. Carefully performed
and accurate hearing tests determine the degree of hearing loss due
to stapes or inner ear involvement.
Treatment of otosclerosis
Drugs are generally not successful in the treatment of otosclerosis.
There is some evidence, in certain cases, that medications may be
useful in preventing further loss of hearing, but the use of these
medications is controversial and may be associated with unwanted
side effects.
Hearing aids
Most patients with otosclerosis benefit from hearing aids unless the hearing loss
is mild. The hearing aids may be fitted to one or both ears. It is
extremely important that hearing aids are well fitted by an
experienced Audiologist working in a team with an ear surgeon.
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Surgery
Stapedectomy surgery is recommended to many patients with
hearing loss due to otosclerosis. Otosclerosis may be present in one
or both ears but the weaker hearing ear is nearly always selected.
Patients with normal nerve function (no sensorineural loss) and
stapes otosclerosis, tend to be very suitable candidates for
surgery. These patients do not require hearing aids after surgery in
the short and medium term. In patients with hearing loss due to
inner ear and stapedial otosclerosis, surgery allows the successful
use of hearing aids.
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The middle ear, illustrating some of the surgical procedures
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Hearing after surgery
Hearing improvement is usually noted within the first few weeks
following surgery but improvement occurs up to 6 months after the
stapedectomy.
Conclusion
Otosclerosis can be cured by skilful surgery. A proper assessment
and examination allows the surgeon to correctly choose the best
candidates for surgery. This assessment includes a thorough
discussion of the possible risk factors and complications.
For more information see:
 Subramaniam K, Rajan GP, Eikelboom RH, Marino R, Atlas MD. (2005) Patient's quality of life and hearing outcomes after stapes surgery, Clinical Otolaryngology, accepted for publication.
Rajan GP, Atlas MD, Subramaniam K, Eikelboom RH. (2005) Eliminating the limitations of manual crimping in stapes surgery? A preliminary trial with the shape memory Nitinol stapes piston, Layrngoscope, 115(2):366-9.
Rajan GP, Eikelboom RH, Anandacoomaraswamy KS, Atlas MD (2004) In-vivo performance of the nitinol shape memory stapes prosthesis during hearing restoration surgery in otosclerosis. A first report. Journal of Biomedical Material Research, Part b, Applied Biomaterials. 72(2):305-9.
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