Otosclerosis


Introduction

 

Otosclerosis is defined as a disease of bony labyrinth by which bone remodeling occurs in labyrinth capsule without concomitant changes in other parts of the skull or skeletal. Bony labyrinth capsule remodeling in otosclerosis occurs in three stages, ultimately leading to the restricted mobility of the stapes and, consequently, conductive hearing loss.

This applies more to women, 90% of hearing loss occurs between 15 and 45 years of age and is often bilateral. Quite often, hearing loss occurs during pregnancy and lactation. The most common symptom is a conductive hearing loss. Although the etiology is not fully known, some researchers believe that it is genetic, while others indicate a viral infection as the onset of the disease inducing factor. However, in many cases, any factor can not be identified.

 

Diagnostics

 

The most common symptom of the disease is progressive conductive hearing loss, sometimes accompanied by tinnitus. In a hearing diagnostics in pure-tone audiometry, conductive or mixed hearing loss with air bone gap is observed in most of cases. The value of gap (the distance between two curves, obtained in pure tone audiometry) depends on the degree of immobilization of the stapes plate and usually dominates in the low frequency band.

 

A characteristic feature of otosclerosis is no acoustic reflex, which means increased sensitivity of the ear to loud sounds.

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Treatment of otosclerosis

 

Currently, the primary method of treatment of otosclerosis is a microsurgical operation reaching the middle ear of the external auditory canal, with prothesis fixing between the long crus of incus and oval window. Prior to fixing of the prothesis both cruses of stapes are removed and in immobilized plate an aperture is made (stapedotomy) or plate is partially removed (partial stapedectomy) or completely removed (stapedectomy). In every case, once the prothesis is fixed, oval window area should be sealed.

 

As a result of the operation, 95% of patients develop better hearing. In approximately 5 % of patients, the operation is not successful or the air-bone gap after months or years is going back to square one. The most likely cause is the displacement of the prothesis. In such a situation, we provide reoperation.

 

In the early postoperative period patient may experience nausea or vomiting, dizziness, symptoms which are associated with irritation of the inner ear. In the long period observation, sometimes tinnitus are observed in the operated ear and dizziness during certain head movements. These symptoms are associated with perilymphatic fistula which is leakage of inner ear fluid around the leak by the prothesis, or position of prothesis piston in reation to vestibular structures. No improvement of hearing after surgery or deterioration of hearing during time, usually is associated with imprecise fixing of prothesis with long crus of incus.

 

In case of so-called cochlear otosclerosis with sensorineural hearing loss treatment with fluoride is proposed. It should be noted that it is not expected in this case hearing improvement but only to stop or slow down the disease activity. However, it should be outlined that the outcome is not satisfactory and alternative form of procurement is receiving hearing aid.

 

Postoperative control

 

The patient usually is discharged from the hospital 1-3 days after the operation, depending on the clinical condition. In the first day patient only wear external dressing.

 

Follow up in policlinic in case of a typical run, takes place on the 7th day after the operation. The doctor removes the dressing from the external auditory canal and in optical microscopy cleans the ear from dissolved dressings. On day 7 suture is also removed from behind the ear.

 

The second visit usually takes place in three weeks after surgery. This is not yet the right time to assess hearing, but usually patients experience significant improvement. If the healing process is carried out in a conventional way, the next visit takes place within 4-6 weeks after surgery and then a pure tone audiometry is performed. Subsequent visits take place at intervals of six months to one year.

 

It should be noted that in each case of the patient's anxiety, discomfort, or suspicion that the healing process does not work properly, patient should promptly report to the hospital, where he was operated, best to the operating surgeon.

 

Krzysztof Morawski MD