Mastoid surgery, known as a mastoidectomy, is the surgical removal of an infected portion of the mastoid bone (the prominent bone behind the ear) when medical treatment is not effective. Although this surgery is considered rare today because of the effective use of antibiotics, it is still used in unresponsive or very severe cases. Mastoidectomy is performed to remove infected air cells within the mastoid bone caused by mastoiditis, ear infections, or cholesteatoma (an inflammatory disease of the middle ear).
The air cells are open spaces containing air that are located throughout the mastoid bone. They are connected to a cavity in the upper part of the bone which is connected to the middle ear. Infections in the middle ear can therefore spread through the mastoid bone, making surgery necessary if antibiotics do not work. A mastoidectomy may also be performed to repair paralyzed facial nerves.