Diagnosis
Given the importance of signs, the diagnosis of otosclerosis is based mainly on audiometry and tympanometry . The latter, in fact, provide more than reliable data and are considered the best tests to perform a precise diagnosis.
Finally, otoscopy is not considered reliable. In fact, patients undergoing this examination often do not show any anomalies.
AUDIOMETRIC TESTS
Audiometric tests help the specialist doctor to assess the patient's hearing loss. The audiometry includes numerous types of tests. The most used ones are:
- Speech audiometry
- Rinne test
- Weber test
- Carhart test
The most important of these, and the first to be performed, is vocal audiometry . If it emerges from this that the patient does not perceive the low tones, the hypothesis of otosclerosis becomes more than concrete.
Each of the other tests is performed with particular modalities and serves as support for the first vocal audiometric test.
They are quick and non-invasive tests for the patient.
tympanometry
It is the test of choice to evaluate the movements of the three ossicles, which make up the middle ear. Evaluation of the ossicular chain reveals how blocked the sclerotic bracket is.
It is a quick and painless test.
TAC AND DIFFERENTIAL DIAGNOSIS
The CT shows the site of the neo-bone formation: the anomalous mass, which blocks the bracket and which affects the cochlea, takes on the appearance of a halo. Thanks to this examination, other pathologies are excluded, such as Paget's bone disease and imperfect osteogenesis. In fact, these two, unlike the otosclerosis, have other characteristic signs of damage to the bone tissue; signs that only the TAC is able to highlight.
Because the CT scan uses ionizing radiation, it is considered a moderately invasive exam.
The following table summarizes some of the pathologies that could be confused with otosclerosis.
| Differential diagnosis | |
| pathology | Description |
| Other diseases of the middle ear | They can be:
|
| Chronic infections | They can determine:
|
| Congenital fixation of the bracket | It is not a degenerative event like otosclerosis and it occurs during the first decade of life |
| Ménière syndrome | It presents other symptoms (for example, nausea and vomiting), due to greater involvement of the cochlea and semicircular canals |
| Paget's bone disease | Presents other bone abnormalities |
| Imperfect osteogenesis | Presents other bone abnormalities |
Therapy
The therapy of otosclerosis is based on two approaches. The implementation of one or the other depends on the health condition of the patient and on the severity of the otosclerosis.
The first curative approach aims to mitigate the main symptom, hearing loss, and to slow down the progressive degeneration of the disease.
The second therapeutic course consists, instead, in two surgical operations: the stapedectomy and the stapedotomy .
NON-SURGICAL THERAPY: PARTIAL RECOVERY OF HEARING
By using a retroauricular hearing aid, it is possible to recover part of the hearing ability. It is the first therapeutic option, able to provide appreciable results, as long as the hearing loss is moderate.
Furthermore, since otosclerosis has a degenerative course and hearing loss becomes more and more severe, drugs able to slow down its progression have been studied. They are:
- Sodium fluoride . Taken orally every day, it serves to regulate the bone replacement mechanism, at the level of the bracket. The results are not entirely satisfactory and side effects may occur.
- Bisphosphonates . They also regulate bone turnover and are taken by those who are intolerant to sodium fluoride. It is not entirely effective.
SURGERY: INTERVENTION TECHNIQUES
Surgery is used when patients show severe and not remediable hypoacusis with a hearing aid alone. There are two possible operations:
- The stapedectomy . It consists of removing the sclerotic bracket and replacing it with a prosthesis. In this way, the normal conduction of the sound signal is restored, through the movement of the three ossicles. The replacement bracket can be metal or plastic.
Figure: the main sequences of the stapedectomy operation. From the wellness.com website
- The stapedotomy . It's a new surgical technique. It involves the removal of a part of the bracket: head and arches. The base, which is the part connected to the cochlea, is instead preserved. A hole is drilled on it, by means of a micro-drill or a laser, inside which a teflon prosthesis is inserted, similar to a small piston. The piston is hooked to the anvil and serves to transmit the acoustic signal of the ossicular chain.
Figure: the main sequences of the stapedotomy operation. From the wellness.com website
Surgery: deepening
The two techniques compared:
The stapedotomy has become the technique of choice for the treatment of otosclerosis. Compared to stapedectomy, it is more reliable and less invasive. In fact, with the partial removal of the bracket, the risk of damaging the cochlea is less.
Success, limits and complications of the intervention:
In 95% of the cases, the intervention is successful and the patient recovers most of the hearing ability. In some individuals, improvement is immediate; in other subjects, instead, it takes a few months to see the positive effects of the intervention.
The main limits of the operation are two. If we are faced with sensorineural otosclerosis, the recovery of hearing can be more difficult. The cochlea, in fact, is a very delicate organ. The second obstacle concerns tinnitus: if present, they are not extinguished by surgery.
Finally, complications . As in any surgical operation, there are possible dangers for the patient. Being a delicate organ, the ear (and some of its internal structures) may be irreparably damaged during the operation. For example, the surgeon may inadvertently injure the eardrum, cochlea or nerve endings that carry the signal to the brain, causing deafness. Therefore, in order not to completely compromise the patient's hearing ability, the two ears are never operated together.
Prognosis
Otosclerosis, if left untreated, always has a negative course. For some, it is worse than for others, but in any case, the quality of life of the patient suffers greatly.
On the other hand, surgery can restore good hearing, even in those with severe otosclerosis. The risk / benefit ratio of the transaction is in favor of the latter. Therefore, the specialist doctor advises you to undergo surgery.
A separate discussion must be made for those who, after the first operation, suffer irreparable damage to the operated ear. In such circumstances, the physician must be cautious and evaluate, with the patient himself, whether to continue with the second operation. In fact, another failure would result in an irreparable bilateral deafness.
Finally, the current retro-auricular hearing aids should not be forgotten: they guarantee a good hearing recovery and a good quality of life, especially in the initial stages of otosclerosis.
