Otosclerosis – causes, symptoms & therapy

Otosclerosis describes a disease of the inner ear, which usually also affects the middle ear. The eardrum separates the outer auditory canal from the middle ear. The ossicles malleus, anvil and stirrup are located behind the eardrum. They are responsible for transmitting sound through the inner ear to the auditory nerve. The impulses can then travel through the auditory nerve to the brain. This function is guaranteed by the movably connected auditory ossicles.

Otosclerosis involves a remodeling process that shows signs of inflammation, which in turn results in the loss of the flexible moving function of the stapes. The elastic suspension of the stirrup ossifies and the sound can no longer be transmitted or only imperfectly. Those affected therefore often suffer from hearing problems such as hearing loss or tinnitus .

On average, otosclerosis occurs quite frequently with about one disease per 100 inhabitants, with women being affected more often than men. Otosclerosis is also more common in the white population than in people of other colors. In almost every case, the disease occurs in both ears, and other family members are often also affected by the disease. Otosclerosis is often observed in people between the ages of 20 and 40, but ossification begins even before the first symptoms appear.

causes

The causes of otosclerosis have not yet been fully elucidated. However, at least the influencing factors and the connections between the changes in the tissue are known. In the case of otosclerosis, the changes only occur in the petrous bone. It is a bony structure surrounding the inner ear. The changes in certain parts of the petrous bone occur particularly frequently.

The first changes usually begin at the so-called oval window, which represents the transition from the middle to the inner ear. At this point, the stirrup is movably attached, it transmits the vibrations of the sound to the fluid in the inner ear.Otosclerosis causes tissue and bone to grow in this area, walling in the footplate of the stapes, resulting in restricted movement. As a result, the sound waves in the ear can only be transmitted insufficiently. Under certain circumstances, these changes can also occur in other inner ear areas.

Otosclerosis can also possibly arise due to a viral infection (e.g. mumps , measles , rubella ). Experts also suspect that so-called autoimmune processes (body mistakenly fights its own tissue) could be responsible for the development of otosclerosis.

Hereditary factors are also possible, since otosclerosis often runs in families. So if one parent has otosclerosis, there is an increased risk in the biological children of also developing the disease. In general, women are affected twice as often as men, and the first symptoms can usually be detected during pregnancy or because of the use of contraceptives. It can therefore be assumed that hormonal reasons may also lead to otosclerosis.

symptoms and course

The symptoms that otosclerosis causes generally affect hearing. This decreases gradually, usually in one ear first. The change is often similar to a sudden hearing loss and can sometimes improve again. In the further course, however, both ears are usually affected by the otosclerosis. There are patients who tend to hear better in a noisy environment. Ringing in the ears such as tinnitus or, in rare cases, dizziness can also be symptoms of otosclerosis.

Diagnose

The diagnosis of otosclerosis is often very difficult, especially in the early stages, since the ENT doctor cannot detect any changes in either the eardrum or the middle ear. Only in rare cases can otosclerosis be recognized on the eardrum by so-called Schwartze signs (reddish colouration). As a rule, the hearing test is usually rather inconspicuous.

If otosclerosis is suspected, the doctor often also checks the function of the muscles in the middle ear, which can identify possible pathological changes. A hearing test and a hearing test with the help of a tuning fork are particularly important in the diagnosis. In this way it can be determined how far the hearing loss is already present. A so-called conductive hearing loss is often diagnosed. With this type of hearing loss, the patient perceives a sound worse in the normal way than via the vibration of the cranial bones, in which the sound is transmitted directly to the inner ear.

Otosclerosis can also lead to pure sensorineural hearing loss. As a rule, a language test is then carried out, in which it can be determined to what extent the person concerned understands spoken words and sentences worse than a person with normal hearing. Depending on the clinical picture, examinations such as X -rays of the ear region, balance tests, CT or MRT or TCS (tympano-cochlear scintigraphy) are also useful.

treatment and therapy

Otosclerosis can only be treated with the help of an operation on the middle and inner ear. The so-called stapedectomy is one possibility for this. During this operation, the doctor removes the stirrup using fine instruments or a laser. The doctor removes not only the attached stapes but also a part of the footplate and replaces it with a prosthesis, the so-called stapesplasty. The doctor inserts this prosthesis between the incus and the area where the footplate of the stapes is missing.

The task of the stirrup – the unhindered transmission of sound vibrations to the inner ear – is now taken over by the prosthesis. Otosclerosis surgery is usually performed under local anesthesia, which has the advantage that changes in hearing can usually be checked immediately and corrected if necessary. The anesthetic is injected into the outer ear canal. The auditory canal is widened with a small incision and the eardrum is detached and folded forward at the rear. This will reveal the stirrup and anvil.

After a successful stapedectomy, the eardrum is returned to its original position. The so-called stapedotomy is another surgical treatment option for otosclerosis, which is usually preferred to stapedectomy. The procedure of the operation is similar, but here only the leg of the stirrup is removed, while the footplate remains. A hole is then drilled into this, either with a laser or with a sharp needle, into which the prosthesis is inserted.

The prosthesis is then attached to the incus. A stamp-shaped prosthesis made of platinum and Teflon is used here, through which the vibrations of the sound are transmitted again without interference. This significantly improves the hearing ability of those affected. A drug treatment that also leads to success is currently not known. If an operation is not possible, the doctor usually prescribes a hearing aid, which improves hearing.The course of otosclerosis usually depends on whether and when treatment is started. Therapy started early can have a positive effect on the prognosis. In more than 90 percent of those affected, an operation can either significantly improve the hearing loss or even eliminate it. In rare cases, however, an operation can also lead to a worsening of the condition.

Some patients occasionally experience dizziness after the operation , and the prosthesis used can also slip in rare cases. In the latter case, a second operation is indicated.

In general, it can be assumed that the course of otosclerosis is faster and less favorable if the disease develops at an early stage. Timely treatment is particularly important then. Without treatment, the hearing impairment can lead to severe hearing loss or even deafness.

prevention

Targeted prevention of otosclerosis is not possible. If those affected suffer from hearing problems or other problems such as tinnitus, they should contact an ENT doctor in good time. This allows the doctor to conduct a thorough examination and provide information about possible treatments. If other family members are affected by otosclerosis, regular check-ups should be carried out by the ENT doctor. In this way, possible otosclerosis can be detected early and treated surgically. Serious consequences can thus be eliminated.