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Mastoidectomy
ALTERNATIVE NAMES: Simple mastoidectomy, modified radical mastoidectomy, tympanomastoidectomy, radical mastoidectomy, Bondi radical mastoidectomy, canal wall-up mastoidectomy.
WHAT IS THE PROCEDURE? In mastoidectomy there is removal of all or part of the mastoid bone. Depending upon the extent of the ear disease, other procedures may be simultaneously performed, such as tympanic membrane repair and/or reconstruction of the ossicular chain.
WHO IS A CANDIDATE FOR THE PROCEDURE? A candidate for mastoidectomy is an individual whose mastoid infection or inflammation is not responding to appropriate medical management or who has cholesteatoma, carcinoma, or osteomyelitis affecting the temporal bone and mastoid.
A mastoidectomy may be necessary in an individual with acute coalescent mastoiditis that develops as a consequence of acute otitis media. In acute coalescent mastoiditis there is infectious destruction of the small bony partitions normally present in the mastoid bone, with subsequent abscess formation. In acute non-coalescent mastoiditis the mastoidectomy is necessary because the infection is not responding to antibiotics, or if it is complicated by formation of an abscess in the soft tissues surrounding the mastoid or impending extension into the inner ear or intracranial cavity.
The other forms of mastoidectomy are indicated for varying diseases of the mastoid. Chronic infectious mastoiditis and most cholesteatomas can often be managed by a less aggressive canal wall-up tympanomastoidectomy procedure. For those individuals, however, with extensive cholesteatoma or cholesteatoma that has recurred in spite of a previous mastoidectomy, then a modified radical mastoidectomy is usually indicated. In the modified radical mastoidectomy the entire back wall of the bony ear canal and mastoid are removed so that now the whole mastoid cavity can be visualized by looking through the ear canal in order to identify early recurrence of cholesteatoma. A mastoidectomy may be necessary to completely resect a cancer of the ear canal, mastoid, or middle ear. A mastoidectomy is also sometimes performed to gain access to certain parts of the cranial cavity for tumor removal.
HOW IS IT PERFORMED? Since the mastoid sits just under and behind the outer ear (pinna), an incision is made behind the outer ear, which is then folded forward, exposing the outer bone of the mastoid. Using high-speed drills, the exterior of the mastoid and the intramastoid bony partitions are removed so that the boundaries of the mastoid cavity are identified. The upper boundary of the mastoid cavity (tegmen) forms the floor of the middle cranial fossa. The posterior boundary is formed by a vascular structure, the lateral sinus, which drains blood from that particular hemisphere of the brain and eventually forms the jugular vein. The deep boundary forms part of the wall of the posterior cranial fossa containing the cerebellum. Also within the deep bony mastoid cavity wall is the facial nerve, cochlea, labyrinth, and endolymphatic sac. If the eardrum or ossicles need to be reconstructed, these procedures are usually performed in conjunction with the mastoidectomy.
WHAT HAPPENS AFTER THE PROCEDURE? For acute infection, a several-day hospitalization is usually necessitated for continued intravenous antibiotics. Certainly if there are infectious complications in the cranial cavity or inner ear, a longer hospitalization is required. If mastoidectomy is performed in the case of chronic disease, it is done either on an outpatient basis or a brief inpatient observation period. A mastoid dressing placed at the time of surgery helps absorb any blood or draining fluid. These dressings are usually removed within 24 hours of the procedure. It is important after mastoid surgery to keep water from entering the ear canal and to take whatever antibiotics have been prescribed and pain medicines as necessary. Antibiotic and steroid-containing ear drops are usually started to help soften any packing material or blood clot in the ear canal, and also to maintain a moist state to facilitate healing of a repaired tympanic membrane perforation. Several office visits are necessary in the first month to observe for infection and to remove any packing material in the ear canal. Fortunately, complications are very infrequent after mastoidectomy. Complications during the procedure itself include facial nerve injury (1 per 1,000), dizziness, deafness, taste disturbance, and infection. Cholesteatomas have approximately a 30 to 50% recurrence rate, which is why many otologists recommend an exploratory procedure approximately six to 12 months after the initial operation in order to identify any recurrence before it gets to be too extensive.
WHAT DO THE RESULTS MEAN? In the case of an acute mastoiditis, the successful outcome is resolution of the infection and prevention of any infectious complications. For chronic otitis media or cholesteatoma, a satisfactory outcome is first and foremost establishment of a safe ear (absence of any infection or disease that can cause damage to the inner ear, facial nerve, or intracranial contents) and restoration of hearing. Successful cholesteatoma surgery is elimination of the cholesteatoma and absence of recurrence on careful surveillance.
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