‫به نام خدا‬
Atelectasis & adhesive
otitis
• Kayvan Aghazadeh M.D
• Assistant prof. of otolaryngology
• Tehran university of medical siences
• Amir Alam hospital
• Middle ear atelectasis is thought to result mainly
from long-standing eustachian tube dysfunction.
• One of the main functions of the eustachian tube is
ventilation of the middle ear and mastoid
• Opening of the eustachian tube allows exchanging
of gases and equalization between the
environment and middle ear.
• The middle ear gases also are exchanged with the
middle ear mucosa.
• Bilateral diffusion between the middle ear cavity
and the blood may be an important factor in
middle ear atelectasis because:
•
the gas composition of the middle ear basically
resembles that of venous blood.
• If the atelectasis develops, the tympanic
membrane becomes retracted onto the
promontory and the ossicles of the middle ear.
• In atelectatic ears, the middle ear space is partially
or completely obliterated, but the tympanic
membrane is not adherent to the medial wall of the
middle ear,
•
and the mucosal lining of the middle ear is intact
• In contrast, adhesive otitis media exists when the
middle ear space is totally obliterated,
• and the tympanic membrane is adherent to the
ossicles and promontory;
•
mucosal surfaces are not present.
• Retraction of the tympanic membrane may lead to
erosion of the long process of the incus and the
stapes suprastructure
• Not all patients with chronic OME develop
atelectasis; in most patients with OME, retraction of
the tympanic membrane is limited.
• In patients with bilateral OME, 1.5% of untreated
ears and 2% of ears treated with tubes developed
severe atelectasis.
•
It may be that repeated bouts of AOM lead to
weakening and thinning of the membrane, which
allows atelectasis
• Sad and Berco showed destruction of the
collagen-containing fibrous layer of the tympanic
membrane in some ears with recurrent infection.
• Collagen destruction within the tympanic
membrane may lead to another complication of
OME—tympanosclerosis
• . Sad and Berco and Tos and Poulsen described four
stages of tympanic membrane retraction:
• stage I, retracted tympanic membrane;
• stage II, retraction with contact onto the incus;
• stage III, middle ear atelectasis; and
• stage IV, adhesive otitis media
• Middle ear atelectasis may be reversible with
ventilating tubes.
•
Sad showed that ventilating tubes improved the
state of atelectatic ears.
• Graham and Knight reported three cases in which
atelectatic tympanic membranes were restored to
their normal position
•
by administration of nitrous oxide during anesthesia
and insertion of a ventilating tube.
• Atelectasis and adhesive otitis media usually coexist
with OME,
• although OME may resolve in these ears, allowing
aeration of the attic and mastoid, but leaving a
collapsed middle ear.
•
In extreme cases, when hearing loss or ossicular
erosion occurs,
• a myringoplasty for the reinforcement of atelectatic
tympanic membrane may be indicated.
• Cholesteatomas may originate from deep
retraction pockets in which desquamated keratin
debris would not be cleared into the ear canal
•
These retraction pockets may occur in the pars
tensa or pars flaccida of atelectatic ears,
•
and should be considered precursors to
cholesteatomas
• Nonpneumatized mastoids may have a limited
ability to buffer pressure changes and
• can manifest as an atelectasis, a retraction pocket,
or a cholesteatoma
‫•‬
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