otosclerosis

Otosclerosis: description

Otosclerosis is a disease of the middle and inner ear, in which parts of the ear harden and ossify. This affects the sound transmission from the middle to the inner ear. The ossification usually begins in the middle ear and can spread in the further course to the inner ear. In later stages, ossification causes increased hearing loss. Even a humming and hum in the ear (tinnitus) can occur. Most otosclerosis first occurs in one ear only and later in the second.

Disturbed bone metabolism

Sound waves that catch the ear vibrate the eardrum at the end of the external ear canal. This translates to the ossicular chain in the middle ear – three tiny, consecutively arranged bones called hammer, anvil and stirrup: The sound transmission runs from the hammer, which is in contact with the eardrum, over the anvil to the stirrup, with the membrane of the oval Window – the entrance to the inner ear – is connected. From there, the acoustic information then reaches the brain via the auditory nerve.

In otosclerosis, the bone metabolism in the area of ​​the labyrinth capsule (bone in the area of ​​the inner ear) is disturbed. As a rule, the first changes to the oval window occur. From there, the ossification spreads to the stirrup, which is in contact with the membrane in the oval window: The stirrup is always immobile, which increasingly interferes with the sound transmission and eventually makes impossible.

Otosclerosis: frequency

About ten percent of the population has a change in the bony structures in the middle and inner ear. Symptoms of otosclerosis, however, only show in about one percent of the population. Women are about twice as likely to be affected as men. Otosclerosis is more noticeable between the ages of 20 and 40 years. However, changes in the ear can persist as early as childhood without symptoms.

Otosclerosis: symptoms

In otosclerosis there is an increasing deterioration of the hearing, usually only at one ear. In about 70 percent of those affected, otosclerosis later develops in the second ear. In women, the first symptoms of otosclerosis often appear during pregnancy. With increasing ossification, the mobility of the ossicles is increasingly limited. This can eventually lead to complete hearing loss (deafness).

About 80 percent of otosclerosis patients also suffer from ear noises such as humming or hum (tinnitus).

Since the nerves for sense of hearing and sense of balance unite and run together to the brain, dizziness can also occur in otosclerosis. However, this is rarely the case.

Individual patients also report that they can hear better than normal in a noisy environment (eg during a train ride) (Paracusis Willisii).

Otosclerosis: causes and risk factors

The exact correlations in the development of otosclerosis are still unknown. Doctors suspect that various factors play a role. Possible causes include, for example, viral infections (measles, mumps or rubella) and autoimmune processes. In autoimmune diseases, the immune system fights its own tissue. In some cases, otosclerosis is also an accompanying symptom of so-called vitreous bone disease (osteogenesis imperfecta).

Otosclerosis is common in some families. Physicians therefore suspect that the disease could be based on a genetic predisposition. So far, five genes have been identified that are altered in people with otosclerosis. They are referred to as otosclerosis genes (OTSC genes) one to five. If a parent suffers from otosclerosis, the children are at an increased risk of contracting.

In women, the first signs of otosclerosis often occur during pregnancy, more rarely during menopause. An increase in symptoms is observed in sick women taking the contraceptive pill. It is therefore assumed that female sex hormones also play a role in otosclerosis. An increased concentration of female sex hormones could accelerate the remodeling of the bone.

Otosclerosis: examinations and diagnosis

For hearing difficulties, an ear, nose and throat specialist (ENT specialist) is the right contact person. In an initial conversation, this person records the medical history (anamnesis). You have the opportunity to describe all the complaints that you have noticed exactly. In order to be able to further narrow down the nature and development of the symptoms, the doctor also asks questions such as:

• Have you been suffering from a viral or bacterial infection lately?
• Do you have family members with frequent or permanent ear complaints?
• Have you had any such complaints in the past?
• Have you had an accident lately?

Physical examination

After the anamnesis, a physical examination takes place. First, the doctor looks at it with a pneumatic magnifying glass in the ear (otoscopy). He can detect any changes in the external ear canal and the eardrum. If an inflammation is the cause of the hearing problems, this is indicated by a clear reddening of the ear canal and the eardrum. In people with otosclerosis, however, the ear canal and eardrum are completely unremarkable. Only in very serious cases, a kind of reddish spot shimmers through the eardrum (Schwartze sign).

hearing test

Then a hearing test is performed, especially a tuning fork test (tuning fork test). With its help, the doctor can estimate from which part in the ear the hearing loss emanates. For this purpose, the tuning fork is struck and placed on different parts of the skull bone or held in front of the ear. The patient is asked to say when he no longer hears the vibration.

With the various test variants, the doctor can find out whether the hearing loss is due to a conductive or a sensory disturbance. In the case of conductive noise, the sound waves in the outer or middle ear can not be forwarded. In a sound sensory disorder, the hearing impairment starts from the inner ear, auditory nerve or brain.

In an otosclerosis, where the ossification is exclusively in the middle ear, the sound conduction is disturbed. Changes in the inner ear (capsular otosclerosis) disturb the sensation of sound. There are also mixed forms with otosclerotic changes in both the middle and inner ear.

If these changes only exist in one ear, this can be determined by a comparison with the other ear. If the changes exist in both ears, this examination is not meaningful and further examinations are necessary.

Further investigations

The doctor also tests the mobility of the eardrum (tympanometry) and the stapedius reflex. The stapedius muscle is the stapes muscle: If the stapes has become immobile due to the otosclerosis, the reflex falls out.

In the language test (speech audiogram) is tested whether affected people hear spoken words already harder.

In order to directly detect changes in the bones, imaging techniques are used. Magnetic resonance imaging (MRI) and computed tomography can visualize the extent of otosclerosis. In addition, dislocations or fractures (for example after a trauma) of the bones can be excluded on the images. An X-ray examination can be useful in individual cases.

Also, only in certain cases, for example, a tympanic cochlear scintigraphy (TCS) and an examination of the sense of balance are performed.

Otosclerosis: treatment

If the otosclerosis is not treated, the ossification increases steadily. Physicians speak of a progressive (progressive) course. Medically, a deterioration can not be stopped. Over a period of time injections of cortisone-containing preparations may help reduce hearing loss. In the long run, however, they can not prevent a deterioration in hearing. The only long-term promising treatment option for otosclerosis is surgery. There are two different methods: stapedectomy and stapedotomy.

Otosclerosis surgery: stapedectomy

Doctors talk about an “ectomy” when something is removed. In stapedectomy, the stapes is removed accordingly – either with the help of surgical instruments or with a laser. Subsequently, an artificial replacement (prosthesis) is used, a so-called stapes plastic. It is like the stirrup itself connected at one end to the anvil and at the other end with the membrane of the oval window. The prosthesis thus completely fulfills the function of the stirrup, so that the sound transmission is ensured.

Otosclerosis surgery: stapedotomy

Stapedotomy is the second possible surgical procedure in otosclerosis. In the past, stapedectomy was usually used. Due to lower risks but the stapedotomy is preferred today. Stapedotomy does not remove the entire stirrup but only the long leg. The stirrup plate, which is attached to the membrane of the inner ear, remains in place. In the plate a small hole is drilled. The prosthesis is now attached to the anvil on one side as on the stapedectomy and on the stirrup plate on the other side.

The operation is done under local anesthesia. The anesthetic is injected into the external auditory canal. The eardrum is detached on one side and made the stirrup so accessible. As a rule, the surgery does not last longer than half an hour. After the operation, the eardrum is folded back. At least up to two weeks after surgery, a special ear bandage (ear tamponade) must be worn. However, the success of the operation is evident – if not during the operation – at the latest in these two weeks.

Treatment of Capsular Otosclerosis

If there is already a capsular otosclerosis (ie an ossification in the inner ear), not only the sound conduction, but also the sensation of sound is usually disturbed. A sound sensory disturbance can not be eliminated with a stapedectomy or a stapedotomy, as the cause of the hearing impairment lies in the inner ear. If the hearing loss is not so serious, hearing improvement can be achieved with a suitable hearing aid. However, this does not stop the process of increasing ossification. Despite the hearing system, the otosclerosis can thus continue to deteriorate. In most cases, surgery is necessary after all. If a bilateral, pronounced sensorineural deafness in capsule otosclerosis can no longer be sufficiently improved with hearing aids, cochlear implantation is the treatment of choice.

Otosclerosis: disease course and prognosis

The prognosis of otosclerosis depends on whether and at what time a treatment takes place. Without treatment, ossification in the ear can lead to severe deafness or even deafness. However, the sooner surgery and follow-up treatment is done on patients with otosclerosis, the better the chances of complete healing. In more than 90 percent of those affected, otosclerosis can be improved or eliminated by surgery.

Dizziness may occur after surgery. He usually disappears within five days. In a few cases dizziness can last longer. Occasionally, hearing may be impaired by surgery.

You can not prevent an otosclerosis. People with family members who suffer from otosclerosis should, however, regularly consult an ear specialist for early detection of signs of otosclerosis. Even in case of general hearing problems or tinnitus, an ear, nose and throat doctor should be consulted immediately. The latter can examine the ears for changes and, if necessary, carry out an operation at an early stage. Thus the risk for a heavy course and possibly permanent damage by a otosclerosis lowered.