What is otosclerosis?
Otosclerosis is a disease of the bone surrounding the inner ear. It can cause hearing loss when abnormal bone forms around the stapes, reducing the sound that reaches the inner ear. This is called conductive hearing loss. Less frequently, otosclerosis can interfere with the inner ear nerve cells and affect the production of the nerve signal. This is called sensorineural hearing loss.
Causes of otosclerosis
The cause of otosclerosis is not fully understood, although it tends to run in families and can be hereditary. People who have a family history of otosclerosis are more likely to develop the disorder. Otosclerosis affects the ears only and not other parts of the body. Both ears are usually involved to some extent. However, in some individuals, only one ear is affected. It usually begins in the teens or early twenties. Some research suggests a relationship between otosclerosis and the hormonal changes associated with pregnancy.
Symtoms & diagnosis of otosclerosis
The commonest symptom is hearing loss that may take many years to become obvious. The degree of hearing loss may range from slight to severe. It can be conductive, sensorineural or both. In addition to hearing loss, some people with otosclerosis may experience tinnitus or noise in the ear. The intensity of the tinnitus is not necessarily related to the degree or type of hearing loss. Very rarely, otosclerosis may also cause dizziness.
An examination by an otolaryngologist is needed to rule out other diseases or health problems that may cause these same symptoms. The amount of hearing loss and whether it is conductive or sensorineural can be determined only by careful hearing tests.
How can otosclerosis be treated?
There is no known cure for otosclerosis. The individual with otosclerosis has several options: do nothing, be fitted with hearing aids, or surgery. No treatment is needed if the hearing impairment is mild. Hearing aids amplify sounds so that the user can hear better. The advantage of hearing aids is that they carry no risk to the patient. An audiologist can discuss the various types of hearing aids available and make a recommendation based on the specific needs of an individual.
The stapedotomy operation
If one ear is affected, the operation may help to locate the direction of sound and hear better in noisy background. If both ears are affected, the operation is usually done on the poorer ear. The patient may still need a hearing aid in the opposite ear.
You may change your mind about the operation at any time, and signing a consent form does not mean that you have to have the operation. If you would like to have a second opinion about the treatment, you can ask your specialist. He or she will not mind arranging this for you. You may wish to ask your own GP to arrange a second opinion with another specialist.
The operation usually takes about an hour. You might be asleep although some surgeons prefer to do the operation with only your ear anaesthetised. A cut is made above the ear opening or inside the ear canal. The top part of the stapes is removed with fine instruments. A small opening is then made at the base, or “footplate”, of the stapes into the inner ear. Some surgeons use laser to perform this procedure. A small piece of vein may be taken from the back of the hand to use as a graft inside the ear. A plastic or metal prosthesis is then put into the ear to conduct sound from the remaining ossicles into the inner ear. You will have packing placed in the ear canal.