Otosclerosis (Calcification of the Middle Ear)
Otosclerosis, which is also known as calcification of the middle ear, is one of the most frequently seen reasons of hearing loss. Otosclerosis is a hereditary disease and may emerge after skipping a couple of generations.
The first stage of hearing is vibration of the eardrum by sound waves, coming along the outer ear channel. This vibration is transferred to the inner ear fluid with the help of the small bones called malleus, incus and stapes. Sound waves are converted to electrical energy in the nerve endings found in inner ear region and transmitted to the auditory centers of the brain via auditory nerve and hearing is provided.
Problems occurring during the transmittance of sound waves to the inner ear fluids through outer and middle ear result in “conductive type hearing loss”. In these types of losses, auditory organs of the inner ear are intact; however sound waves can not reach these organs. Hearing losses originating from inner ear and auditory nerve are called “sensoneural type hearing loss”. In otosclerosis, which is a disease that can also affect the inner ear, both types of losses can be seen together. This type of hearing losses is called “mixed type hearing loss”.
Hearing Loss Due to Otosclerosis
In otosclerosis disease, new bone formations with spongy appearances forms in pieces in the bone structure bearing the auditory organs of the inner ear.
This disease mostly observed in the region called oval window, where the base of the stapes bone, transmitting the sound waves to the inner ear is located. The otosclerosis focus inhibits the vibration of stapes bone and disrupts the transmittance of the sound wave to the inner ear and as a result, conductive type hearing loss occurs.
When these changes affect the auditory organs of the inner ear, nerve type hearing loss called “cochlear otosclerosis” occurs.
The type and extent of hearing loss occurring in otosclerosis depend on the involvement of stapes bone (restriction of its mobility) and the extent of affection of the auditory organs of the inner ear from the disease.
Treatment of Otosclerosis
Medical Treatment: Especially in diseases detected at an early age with rapid progression, some treatments are used to slow down the progression in the hearing loss. However, there is no medical treatment for otosclerosis.
Surgical Treatment: With a surgery called “stapedectomy”, the stapes bone having restricted mobility is removed and a prosthesis that would transmit the sound waves to the inner ear is placed. With this operation that can be performed under local or general anesthesia, 90-95% successful results are obtained and the conductive hearing loss is corrected almost completely in the majority of the patients.
Surgery is not recommended for patients having slight hearing loss or severe nerve type hearing loss in which auditory organs of the inner ear are severely affected. Stapedectomy surgery is recommended to the remaining otosclerosis patients unless a severe health problems preventing surgery is present.
After the surgery, vertigo can occur for a couple of days. Surgical sponges placed in the ear are removed within 7-10 days and patient can return back to their normal lives at the end of this period.
Though risks of stapedectomy surgeries performed with appropriate surgical equipment and surgical techniques are quiet small, 1% total hearing loss risk is present in each operation. Apart from that, complications like perforation of the eardrum, damaging of the facial nerve, infection formation in the ear, dislocation of the piston in the early period may be more rarely observed.
Hearing Aids: Every patient, who can benefit from the surgery can benefit from hearing aids as well. Especially for patients having double sided otosclerosis and not preferring surgery, usage of hearing aids is recommended not to experience the recession of the functions of the inner ear in parallel to the decreasing hearing.