What is a stapedectomy? I have been told that the procedure can improve hearing loss due to otosclerosis.

Lora

In stapes surgery, the surgeon's goal is to improve hearing by restoring sound transmission to the inner ear. To help you understand the procedure, I need to first discuss sound transmission.

Sound is airborne vibration. In order for you to hear, this vibration must make its way through your ear canal and middle ear, eventually stimulating the cochlea. The cochlea is the inner-ear organ that translates vibrational energy into nerve impulses, which are then interpreted by your brain as sound. Sound energy is transmitted to the cochlea through the following pathway:

1. Airborne vibrations in the ear canal cause the eardrum to vibrate.
   
2. Vibration of the eardrum causes a tiny bone embedded in the drum (the malleus) to vibrate as well.
   
3. The malleus is connected to a second tiny middle-ear bone, the incus. As the malleus moves in response to sound energy, this movement is transmitted to the incus.
   
4. The incus is connected to the tiniest middle-ear bone of all, the stapes. The common name for the stapes is the stirrup, because of its shape. Like a stirrup, the stapes has an arch and an oval base. The incus is attached to the arch of the stapes. As the stapes vibrates, the base (known as the "footplate") moves up and down.
   
5. The footplate of the stapes rests on a membrane platform known as the "oval window." Behind the oval window is the "vestibule," a fluid-filled inner-ear compartment. Thus, up-and-down motion of the stapes footplate sets up fluid waves in the vestibule. These fluid waves stimulate the cochlea. The cochlea translates the waves into nerve impulses. Voila! You hear a sound.
   

What is otosclerosis? In this condition, the stapes footplate becomes firmly fixed within the oval window. When this occurs, the footplate can no longer move up and down. Sound transmission stops dead in its tracks before reaching the cochlea.

Stapes surgery is designed to restore sound transmission to the inner ear. One common way to do this is to (1) separate the incus from the stapes, (2) remove the stapes arch, (3) create a hole in the stapes footplate (using a tiny drill or a laser) and finally (4) attach a tiny "piston" to the incus, the tip of which rests in the newly created hole. Thus, sound transmission follows the path: incus to piston (also known as the "prosthesis"), piston to oval-window membrane, membrane to vestibule.