Definition: otosclerosis is a localized hereditary disorder affecting endochondrial bone of the otic capsule characterized by disordered bone resorption and deposition ,leading to replacement of normal compact lamellar bone by abnormal spongy bone of greater thickness,cellularity and vascularity with progressive fixation of stapes.
-Risk factors are mainly hereditary tendency ,endocrinal,pregnancy.
-Aetiology is genetic predisposition ( autosomal dominant transmission),measles,autoimmune,biochemical abnormalities.
-the disease is more common in white population , especially females(2:1) aged between 15 to 45 ,as it’s the commonest cause for bilateral conductive deafness in adults.
– stapedial type is the most common type , due to affection of the anterior margin of oval window in 85 % of cases.
– symptoms are insidious and have progressive course ,being deafness( bilateral, progressive) ,tinnitus, paracusis willsii ( hearing better in noisy places)
-signs are quit voice, intact normal tympanic membrane ,schwartze sign, bilateral conductive deafness with variable degrees.
– Investigations mainly by PTA and CT scan.
- No treatment in mild cases with AB less than 20 dB.
- Stapedectomy is the treatment of choice.
- Hearing aid if the operation is contraindicated , refused,failed.
4.Medical by giving sodium fluoride therapy which is contraindicated in pregnancy, young age , renal dysfunction, rheumatoid.