The Process of Normal Hearing
Hearing is composed of two elements, conductive hearing and nerve hearing (or sensorineural). The ear functions to convert the sound waves that vibrate the ear drum (tympanic membrane) into electrical energy which are transmitted via the cochlear nerve to the brain. This process starts as sound waves strike the ear drum causing movement of the tiny ear bones (ossicles). As the ossicles move, they transmit their energy into a fluid filled chamber that communicates with the fluid of the cochlea. The cochlea is lined with special cells that surround the fluid. As the fluid moves, it distorts the cells. This distortion results in an electrical charge that is sent to the adjacent cochlear nerve for delivery to the brain.
If one (or more) of the ear bones are not moving properly, this results in a loss of the conductive portion of hearing and is interpreted as a hearing loss. If the hearing nerve (cochlear nerve) is functioning normally, restoration of normal ossiclular movement will result in hearing improvement.
What is a stapedectomy?
Otosclerosis is a disease specific to the stapes (the smallest middle ear bone, or ossicle) that limits its ability to move. The hearing loss is gradual, but progressive. A stapedectomy is an operation to remove (or bypass) the stapes bone. The goal of the procedure is to restore normal mobility to the ossicular chain (middle ear bones) allowing full use of the cochlear hearing. Your surgeon will discuss with you the expected hearing result following the stapedectomy.
During the stapedectomy, an artificial piston is placed through a very small hole (< 0.8 mm) that is created in the footplate of the stapes. While otosclerosis typically affects both ears, it is customary to perform the operation one ear at a time. The ear with the greatest hearing loss is often selected first. The second ear, if affected, can have the surgery performed at a later time, if desired.