Your hearing loss is caused by a disease called "Otosclerosis." Otosclerosis is a bony growth around one of the middle ear bones (stapes) that carries sound. Since Otosclerosis is hereditary, someone in your family may also have had this condition. However, the fact that you have had Otosclerosis does not necessarily mean that your children will develop otosclerosis. Diseases such as scarlet fever, ear infection, measles, flu and exposure to noise do not cause Otosclerosis. Approximately 5% of all persons with hearing problems have otosclerosis.
FUNCTION OF THE NORMAL EAR
Sound is carried from the eardrum to the inner ear and hearing nerve by a chain of three small bones called ossicles. The third bone in this chain is shaped like a stirrup and is called the stapes (stay-peas). The stapes transmits the sound to the inner ear and hearing nerve. The hearing nerve carries the sound to the brain where it is interpreted as speech.
THE OTOSCLEROTIC EAR
If it were possible to examine your stapes before you had a hearing loss, we would have seen tiny particles of bone around the stapes. These bone particles, which are not present around a normal stapes, gradually grow until they eventually stop the movement of the slapes. Usually it takes many years before this hardening process stops the stapes from carrying sound to the hearing nerve.
Otosclerosis may involve other parts of the inner ear as well as the stapes. Otosclerosis, wherever it is found, can give off a toxic substance that damages the hearing nerve and causes a nerve hearing loss. Nerve hearing losses are permanent and cannot be restored by surgery or medicine. Another consequence of a nerve hearing loss is ear and head noises. These noises might sound louder when a person is tired, nervous or in a quiet place. The amount of ringing is not necessarily related to the amount of hearing loss. Very rarely does Otosclerosis alone cause total deafness.
TREATMENT OF OTOSCLEROSIS
For many years there was little help for the patient with otosclerosis. However, as the result of research, an operation was developed to restore the hearing in patients with Otosclerosis. This operation is known as "stapedectomy." Former operations on the stapes, such as fenestration or stapes mobilization, have proven to be unsatisfactory. Because stapedectomy has a high rate of success, we now recommend stapedectomy for patients with otosclerosis.
In some patients, as mentioned before, the toxin from the otosclerosis will cause a nerve hearing loss. A specialized x-ray will usually show the extent of the Otosclerosis. Medical treatment can prevent this type of nerve hearing loss from getting worse. If we suspect a nerve hearing loss from otosclerosis in your case, we will recommend this special x-ray.
A hearing test revealed that your hearing loss is:
Right ear _____________ % Left ear _____________ 0/0
- Your hearing nerve is normal and you are a good candidate for a stapedectomy.
- Your hearing nerve is not normal. If the stapedectomy is successful, you should regain better but not normal hearing.
- Your hearing nerve is not normal. If the stapedectomy is successful, you will be able to hear in many situations without a hearing aid, but you will need a hearing aid under some conditions.
- Your hearing nerve is not normal. If the stapedectomy is successful, you will benefit more from the use of your hearing aid, but you will still need to wear a hearing aid.
- Your hearing nerve has been severely damaged. For this reason, the chance of surgery improving your hearing is greatly reduced. If the stapedectomy should prove successful, your hearing will be improved to the extent that you may be able to use a hearing aid.
You have approximately ____ of 100 chances that your hearing will be improved and ____ chance out of 100 that your hearing will be worse.
In ear surgery, as in any surgery, there is no guarantee of success.
THE STAPEDECTOMY OPERATION
A stapedectomy is performed under general anesthesia, requires only a few days hospitalization and a short convalescence. Before surgery, the ear is anesthetized by the use of ear drops and an injection of a local anesthesia. At the beginning of the operation, a small piece of tissue is taken from behind the ear. The ear drum is then carefully turned and the fixed stapes and the Otosclerosis are removed. The tissue is placed over the opening that the stapes formerly occupied. A stainless steel prosthesis that replaces the fixed stapes is put into position on the tissue graft, and is connected to the normal second bone of the ear. Finally, the eardrum is replaced into its original position.
Now the sound travels from the eardrum to the first two ear bones and then through the steel replacement prosthesis to the hearing nerve. Since the fixed stapes is now removed and the hearing chain is once again movable, the hearing improvement obtained is usually permanent. The only further hearing loss expected would be that related to the normal aging process or to the toxin from Otosclerosis that is now controlled by medicine.