What is otosclerosis?
Otosclerosis is a disease of bone that affects the bone of the ear but no other bone in the human body. The cause of otosclerosis is unknown. Approximately 50% of patients with otosclerosis have a family history, strongly suggesting a genetic factor. Other proposed causes include a metabolic disease of bone, an autoimmune disorder, a response to measles virus, and an abnormal response to hormonal factors. Otosclerosis usually begins in the late twenties or thirties, is more common in women than men, and is bilateral (affects both ears ) in half of the patients.
What are the symptoms of otosclerosis?
Otosclerosis most often affects the stapes bone and causes a conductive hearing loss (see how we hear). Hearing loss is therefore the most common presenting symptom of otosclerosis. Other associated symptoms include tinnitus (a noise in the ear), and ear fullness.
How is otosclerosis treated?
Therapeutic options for otosclerosis include:
- Expectant observation if the hearing loss is mild or unilateral (only one ear)
- Amplification in the form of a hearing aid, which should restore hearing to normal in most instances, and is risk free
- Surgical removal of the stapes bone and replacement with a prosthetic bone, so called stapedectomy. The main risk of stapedectomy surgery is complete loss of hearing in the operated ear, due to inner ear injury. This complication occurs in approximately 1% of surgeries. Other risks include:
- The facial nerve, the nerve that moves the muscles on the side of your face that controls smiling, closing the eye and wrinkling the forehead, can be injured. If this nerve is injured you can have weakness or paralysis of the muscles of your face on the side of the surgery. This is a rare complication and can be minimized by using a computer, during the surgery, to monitor the facial nerve.
- Dizziness is common for the first week after surgery but rarely persists
- Tinnitus, a noise in the ear, may occur after surgery, particularly if there is a loss of inner ear function.
- Taste disturbance is common for a few weeks after surgery and may persist.
Occasionally, otosclerosis will invade the inner ear and cause a severe to profound sensorineural hearing loss. This can happen with or without disease affecting the stapes. Such patients are not stapedectomy candidates. They wear hearing aids until their hearing loss becomes of such a degree as to merit a cochlear implant.