Otosclerosis
| Classification according to ICD-10 | |
|---|---|
| H80 | Otosclerosis |
| ICD-10 online (WHO version 2019) | |
The otosclerosis is a disease of the bone, which the inner ear surrounds (labyrinth capsule). At first, inflammation-like bone remodeling processes occur. Furthermore, the fixation of the stapes footplate in the oval window leads to slowly increasing conductive hearing loss . Foci of illness in the area of the snail can also cause inner ear hearing loss.
root cause
The cause of the disease is not clear. Be discussed due to the presence of family clusters an autosomal - dominant inheritance with variable penetrance (frequency of occurrence of symptoms in existing genetic variation), viral infections (such as measles ) and hormonal influences. Which hormones are involved, as well as the effect on the course of the disease, can only be guessed. A significant involvement of the female sex hormones can be assumed because of the onset of the symptoms of otosclerosis or their increase in pregnancy , the use of contraceptives and the change in the hormone balance after menopause .
| Frequencies of otosclerotic foci | ||||
| oval window | ~ 90% | |||
| round window | ~ 40% | |||
| Cochlea | ~ 35% | |||
| internal ear canal | ~ 30% | |||
| Semicircular canals | ~ 15% | |||
As a result of the resorption of the normal bone tissue and the formation of an initially heavily vascularized and later compact bone tissue, remodeling processes occur in the inner ear.
The main localization is the area of the oval window ( fenestra vestibuli or fenestra ovalis ), which fixes the stapes to the surrounding bone ( stapes ankylosis ). Therefore, the sound waves from the ossicular chain can no longer be fully transmitted to the cochlea of the inner ear. Otosclerotic foci in the vicinity of the snail are suspected to be the cause of the additional inner ear hearing loss that often occurs.
The table shows the most frequent localizations of the changes, although other symptoms may of course also predominate depending on the localization.
Occur
It primarily affects women (almost twice as often as men) in the white population between the ages of 20 and 40. People of a different skin color are affected by this disease much less often, which can be interpreted as an indication of a genetic cause. About one percent of whites are symptomatically ill, however otosclerosis is not equally severe in all patients. In a much larger proportion of this population group, histological changes can be detected without symptoms ever occurring.
Both ears are affected in around 70% of all cases, but usually to different degrees.
Symptoms
Otosclerosis usually begins in one ear with slowly increasing hearing loss . Later, the other ear is often also affected. It is not uncommon for the disease to be associated with noise in the ear ( tinnitus ), which is often localized in the frequency range of the lower tones and is usually extremely annoying for the patient. Patients often notice that they can better follow conversations when there is ambient noise ( Paracusis Willisii ). This phenomenon is explained by the fact that, on the one hand, the patient hears disturbing noises, especially in lower pitches, and on the other hand, the conversation partner speaks louder because of the ambient noise. Despite their hearing loss, patients with otosclerosis often speak noticeably quietly because they hear their own voice loudly through bone conduction, but the ambient noise is low. As mentioned above, symptoms often increase during pregnancy.
After a long period of illness, otosclerosis can lead to numbness . In rare cases - if the area of the equilibrium organ, which is also part of the inner ear, is affected - dizziness can also occur.
Depending on the location of the otosclerosis foci, the following hearing impairments can be described:
- the sound conduction disorders (so-called middle ear type, in about 80% of patients)
- mixed conduction and sensation disturbances (so-called mixed type, around 15% of patients)
- the sensorineural sensation disorder (so-called inner ear type, in about 5% of patients)
Diagnostics / findings
During an ENT examination, the eardrum , middle ear and the function of the ear trumpet ( Eustachian tube ) appear normal. Occasionally, in otosclerosis, a pathognomonic finding is the so-called " black sign", a reddish area that shimmers through the eardrum as an expression of an active inflammation.
During the hearing test ( audiometry ), when the stirrup footplate is fixed, a sound conduction disorder and, not infrequently, an additional sound sensation disorder when the snail (cochlea) is infected. The so-called Carhart depression is typical : it is a trough-shaped depression in the bone conduction threshold curve in the range from 1 to 4 kHz. Otosclerosis prevents the osteotympanic bone sound from affecting the inner ear. The Carhart Depression is by no means always to be found. It is noteworthy that the Carhartian depression disappears after successful stirrup surgery, since the effect of the osteotympanic bone sound resumes. The sound conduction disturbance is of the so-called stiffening type, in the range of the natural frequency of the oscillating system (approx. 2-3 kHz) the sound conduction disturbance is less pronounced. In the speech audiogram , a hearing test with numbers and monosyllabic words in different volume levels, one can objectify a limited understanding of speech.
<: Bone conduction, upper curve
X: air conduction, lower curve
With the help of the Rinne test , a hearing test with a tuning fork , one can distinguish between sound conduction (affected areas of sound transmission such as eardrum, auditory ossicles, oval window) and sensorineural hearing loss (this affects the perception of sound in the sensory cells in the inner ear).
In the case of unilateral conductive hearing loss, the Weber experiment shows lateralization to the poorly hearing ear, i.e. H. the sound of a tuning fork placed roughly in the middle of the top of the skull is felt louder in the actually poorer hearing ear.
The Gellé experiment is used if a fixed ossicular chain is suspected (as is the case with otosclerosis). A sound is transmitted directly to the skull bone with a tuning fork. A balloon (Politzer balloon) is used to exert pressure through the external auditory canal on the eardrum and thus on the ossicles. With a normal hearing person, the tuning fork tone becomes significantly quieter, with a fixed ossicular chain the tone remains the same.
If there is a pronounced ossification of the oval window, this can also be demonstrated in an X-ray or computer tomography image of the ear region.
If there is a suspicion of involvement of the organ of equilibrium in the inner ear, balance tests will be carried out to determine the extent and objectivity of the complaints .
therapy
Conservative methods
Up to now, otosclerosis cannot be influenced by medication. Attempts at treatment with sodium fluoride brought no change in the course of the disease. In the case of conductive hearing loss such as otosclerosis, a hearing aid can improve hearing very well. However, this does not affect the progression of the disease, regular hearing checks are required.
Operational procedures
The operation in which the fixed stapes is partially or completely replaced by a prosthesis is called stapesplasty . It is performed via an endaural approach.
In staple tomy , only the upper part of the stapes is removed, the immobile stapes footplate is opened with a needle or a laser and an artificial stamp (now mostly made of titanium or platinum and Teflon) is used for sound transmission. This surgical technique is the method of choice today and leads to a significant reduction in conductive hearing loss in more than 90% of cases. Any additional internal ear hearing loss, however, cannot be improved by the operation.
Stapedotomy with laser (1 = long anvil limb, 2 = hammer handle, 3 = stapes footplate with circle of the pilot laser, 4 = chorda tympani (taste nerve), 5 = tendon of the stapes muscle)
Laser shot on the footplate
Circular opening in the footplate to accommodate the prosthesis
Stapes prosthesis ("Piston"), platinum-Teflon prosthesis (left), titanium prosthesis (right)
VIDEO (animated gif): Otosclerosis, perforation of the footplate with laser, slow motion
Under Staped ectomy is subsequently being understood as the removal of the entire stapes, stapedotomy a prosthesis is inserted.
Such an operation can be performed under local anesthesia or general anesthesia and takes around 30 minutes for an experienced surgeon, but also significantly longer under difficult conditions. Local anesthesia has the advantage that the patient can be addressed during the operation and the hearing improvement can be checked immediately, although involuntary movements by the patient can be dangerous. The postoperative stay in the clinic is usually 3–7 days. Complete healing takes 4-6 weeks. Employment can usually be resumed after 3–4 weeks. A not uncommon complication is temporary dizziness. a. can be caused by a poorly fitted implant.
history
The first description of a bony stapes fixation was published by the Italian doctor Antonio Valsalva around 1740. 100 years later, the English doctor Joseph Toynbee (1815–1866) examined 35 cases of hearing loss that were due to stapesankyolysis. Adam Politzer , a Hungarian-Austrian doctor who worked in Vienna , was the first to describe otosclerosis as an independent disease in 1893.
In 1876 Johannes Kessel (1839–1907) proposed an operation to treat otosclerosis for the first time . However, it was not until 1956 that the stapes sculpture was described by John J. Shea Junior. In 1970 Dietrich Plester expanded it to include a partial stapedectomy.
Surely the most famous patient with otosclerosis was Ludwig van Beethoven (1770–1827). In 1798 the composer's hearing problems began, which finally resulted in complete deafness in 1819.
literature
- Boenninghaus, Lenarz: ENT . Springer, Heidelberg 2005 ISBN 3-540-21969-2
- Cotran, Kumar, Collins: Robbins Pathologic Basis of Disease . Saunders, 1999 ISBN 0-7216-0187-1
- Pschyrembel: Clinical Dictionary . 257th edition
Web links
- Otosclerosis on Onmeda.de
- Otosclerosis on Medizinfo.de
- Mudry, Albert: Adam Politzer (1835-1920) and the Description of Otosclerosis. Adam Politzer Society
- Otosclerosis and hearing impairments - Infothek of the Hörkomm.de project - Barrier-free hearing and communication in the world of work
Individual evidence
- ↑ W. Becker; HH Naumann; CR Pfaltz: Ear, Nose and Throat Medicine. Short textbook with atlas part differential diagnostic tables. Georg Thieme Verlag, Stuttgart, New York, 1986 ISBN 3-13-583003-9 p. 115
