You can think of the mastoid bone like a bony sponge riddled with small air pockets that can harbour the very harmful cholestetoma (a collection of abnormal but non-cancerous skin cells in the ear). In mastoidectomy, the surgeon removes these cholestetoma. If the disease has covered the three tiny bones of the ear known as ossicles, the surgeon will remove these too. The facial nerve runs through the ear’s bony canal and if the bone is destroyed by the disease, it affects the facial nerve as well. The surgeon will take utmost care to protect this nerve. After he has removed all the infected and diseased portions, he will use a graft to seal up any hole in the eardrum and pack the ear with gelfoam. The surgeon may also undertake reconstruction of the ear’s hearing apparatus along with this surgery or perform it as a second stage procedure.