Mastoidectomy
Mastoidectomy
is the surgical procedure to open the
air cell system of the mastoid bone.
The mastoid bone is the bone behind the
ear. It is connected to the middle ear
through a series of air cells. The
mastoid bone contains the facial nerve
and the inner ear.
Normally, the
middle ear and mastoid are filled with
air. This air reaches these structures
through the Eustachian tube. Every time
one swallows or yawns, the Eustachian
tube opens, allowing a small puff of air
to enter the middle ear and mastoid, and
permitting drainage of the thin mucus
produced by the linings of the middle
ear and mastoid. The linings or mucosa
of the middle ear and mastoid normally
produce a thin watery mucus and absorb
oxygen and nitrogen. If the Eustachian
tube is blocked or not working, then the
air inside the middle ear and mastoid
will be absorbed by the mucosa and fluid
will build up within the middle ear and
mastoid.
In patients
with chronic ear infections or
cholesteatoma, a mastoidectomy might be
need to be performed in order to remove
infected tissue and to re-establish a
drainage pathway for mucus.
Mastoidectomy
is commonly performed under general
anesthesia. High speed drills are used
to remove the bone of the mastoid, and a
microscope is used to magnify the
delicate structures of the middle ear.
A facial nerve monitor is used to
monitor the function of the facial nerve
during the procedure. This helps to
identify the facial nerve and to avoid
injury to the facial nerve.
There are three
different forms of mastoidectomy: simple
mastoidectomy, modified radical
mastoidectomy, and radical mastoidectomy.
Simple mastoidectomy involves removing
the bone of the mastoid and opening up
the space that connects the middle ear
to the mastoid. In this procedure the
ear canal bone is maintained, thus some
surgeons call this procedure "canal wall
up" mastoidectomy. Once the mastoid
disease has been cleaned, tympanoplasty
can be performed.
Like the simple
mastoidectomy, a modified radical
mastoidectomy also involves the removal
of the mastoid bone; but in this
procedure, the ear canal wall is also
removed. Some surgeons refer to this
operation as a "canal wall down
mastoidectomy." A common cavity is
created between the ear canal and the
mastoid. This procedure exteriorizes
the mastoid, in other words, the mastoid
cavity is exposed to the outside world.
An enlargement of the ear canal, called
a meatoplasty, is performed at the same
time. This procedure is done for
patients with extensive or recurrent ear
infections. Having the mastoid exposed,
allows the mastoid cavity to be cleaned
in the office following surgery. Like
the simple mastoidectomy, tympanoplasty
can be performed to reconstruct the
eardrum and the sound-conducting
mechanism of the middle ear.
Lastly, for
patients that have severe, unremitting
middle ear infections, a radical
mastoidectomy can be performed. In this
procedure, the mastoid bone, the ear
canal and the ossicles are removed. The
middle ear mucosa is removed and the
Eustachian tube is blocked off. No
attempt is made to reconstruct the ear
drum or the hearing mechanism.
All forms of
mastoidectomy share similar potential
risks: hearing loss, tinnitus,
dizziness, facial paralysis, or loss or
altered taste on the tongue.
