In this condition the bone of the inner ear remodels itself into disorganized plaque like bone. The most common area for these plaques is the anterior portion of the footplate where the third bone of hearing or stapes connects into the inner ear. Because of this plaque formation, stapes is not able to vibrate and transmit the sound into the inner ear. This creates a conductive hearing loss. Otosclerosis can rarely result in sensorineural hearing loss when it affects the cochlea. The condition is caused by both genetic and environmental factors. In cases of active progressive otosclerosis/otospongiosis the disease could be potentially halted by treatment with fluoride supplement. In most cases the condition stabilizes spontaneously and the conductive hearing loss could be treated with hearing aid, bone conduction devices or microsurgery (stapedotomy).
Otosclerosis plaque on the anterior crus of the third bone of hearing called stapes
Schematic of the middle and inner ear showing the connection of stapes to the inner ear
Schematic of stapedotomy surgery with prosthesis in place
Images used with permission from Robert K Jackler