Otosclerosis is a condition characterised by progressive fixation of the smallest and innermost of the auditory ossicles, the stapes, by new bone. This leads to progressive, conductive deafness.
Otosclerosis is believed to be an inherited disorder and there is a strong family history in many cases. The gene is believed to show variable ‘penetrance’ and may therefore skip about between generations, so that some patients will present without a family history while others will have had a number of relatives affected. The pathology is a growth of new bone starting at the front of the footplate of the stapes and progressing to involve the whole margin, often with considerable thickening of the footplate. Typically, both ears are affected, but the development of the disorder may be asymmetrical and sometimes only one ear is affected for a long period. It is important to understand that the process of new bone formation sometimes affects the inner ear as well.