Otosclerosis is an abnormal, microscopic growth of bone in the walls of the inner ear which causes the stapes bone, commonly called the "stirrup," to become frozen in place or "fixed." Normally the stapes, the smallest bone in the body, vibrates freely to allow the transmission of sound into the inner ear. When it becomes fixed to the surrounding bone, it prevents sound waves from reaching the inner ear fluids and thus hearing is impaired.
Q&As about Otosclerosis
What is otosclerosis?
In a normal ear, sound which consists of vibrations of air molecules is funneled by the auricle, or "outer ear," through the ear canal to the ear drum. Movements of the ear drum are transferred to the ossicles, the small bones of the middle ear, and the stapes vibrates in and out of the oval window. The vibration of the stapes sets up a movement of the inner ear fluids. This, in turn, stimulates the fine sense organs of the inner ear which then stimulate the auditory (hearing) nerve which carries the sound energy to the brain. It is this sequence of events that results in normal hearing.
How is otosclerosis treated?
No medication has been proven to be effective in the treatment of otosclerosis. Although a hearing aid can be worn successfully by most patients, natural hearing is preferred. Surgery has been found to be the most effective method of improving hearing loss caused by otosclerosis.
Surgical treatment has been available for more than 50 years. The first operation for this disease was the fenestration procedure which required mastoid surgery and an artificial opening in another part of the inner ear. The attention of the ear surgeons then became focused on the diseased stapes itself and the stapes mobilization procedure was developed. With the improvement in surgical technique, the treatment of choice then became the stapedectomy. This operation was first performed in 1956.
The stapedectomy operation involves the removal of the diseased bone and its replacement with an artificial substitute. Local or general anesthesia is used. The surgery usually takes place entirely through the ear canal so that no outer incisions are made. The stapedectomy is done using an operating microscope. The surgeon will first fold forward approximately one half of the ear drum so that he or she can reach the area where the stapes is located. The superstructure or stirrup portion of the stapes is then removed with fine instruments. There are several ways to properly manage the fixed footplate, depending upon the individual case. Most commonly, a small opening is made through the fixed plate with fine instruments, a micro drill, or a laser. In some cases the entire footplace may be removed. There are a variety of artificial stapes or "prostheses" that are available to replace this diseased bone. The most common prosthesis used, as shown in the diagram, is a "piston" which attaches to the incus and inserts into the vestibule of the inner ear, thus bypassing the fixed stapes footplate.
Can I have the operation? What are my chances of its success?
An examination by an ear specialist, including a hearing test, is necessary to determine if you are a candidate for the operation. There are many different causes of deafness and not all patients with otosclerosis are candidates for stapedectomy.
The chances of obtaining a good result from this operation are about 90 percent. This means that about nine out of 10 patients will have improvement of hearing up to the level at which the inner ear is capable of functioning. If the inner ear functions normally, then nearly normal hearing can be restored. Approximately 7 percent of all patients have only partial recovery of hearing and 2 percent remain at the same level as before the surgery. The main risk is a 1 percent chance of developing inner ear hearing loss following the procedure due to factors that, as yet, are not entirely understood. For this reason, only one ear is operated on at a time and the worst ear is always done first.
What should I know before the operation?
Stapedectomy is usually performed on an outpatient basis. Your medical history, physical examination, a discussion about details of your surgical procedure and the associated risks and benefits will be addressed during the preoperative visit. At this time, you will be asked to provide your doctor with a list of the medications you are taking, including dosage and the frequency they are taken. You also will be asked to provide information about any known drug allergies.
If you have symptoms of a cold one week or less prior to the date scheduled for your operation, you should report this at once to your doctor.
What can I expect after the operation?
The evening after the operation you should lie quietly on the unoperated ear. Do not be alarmed if you have some dizziness for the first few days after the operation. Following the stapedectomy procedure, most patients are able to go home that evening or the next morning.
At the time of surgery, a packing is placed in your ear canal. You will not notice a hearing improvement until this is removed one week after the surgery. It often takes one to two weeks for the hearing to reach its maximum level of improvement. At first, patients usually complain of a "hollow" sensation as though they were hearing from the bottom of a barrel or in a cave. Sounds may have an unattractive quality or may seem very loud, but they will gradually become normal.
Because a small taste nerve (the chorda tympani) that runs through the ear, it is not unusual for the taste sensation to be altered for several weeks or months following the stapedectomy operation. Recovery of normal taste sensation usually occurs.
It is best not to blow your nose for one week after surgery. You should keep water out of the ear for at least two weeks after the operation. When you shampoo or shower, place a cotton ball which has been lightly covered with petroleum jelly into the outer ear canal. Do not go swimming. You may be given a prescription for antibiotics to be taken orally. The ear drum will heal quickly. Two weeks following surgery, you may resume normal activities, including flying.
If at any time after surgery, you should experience sudden hearing loss, pain, dizziness, or any new symptom related to the operated ear, you should notify your doctor immediately. Complications are very rare. However, early intervention may influence the final outcome.
Following your stapedectomy operation, it is important that you have periodic hearing tests. These tests provide your doctor with accurate information regarding the results of your surgery, the status of your unoperated ear, and the possible benefit of surgery should this ear also be affected by otosclerosis.
If you would like to schedule an appointment for an examination by an Infirmary otolaryngologist, a physician who specializes in the medical and surgical treatment of the ear, nose, and throat, please call our Physician Referral Service at 617-573-3954.