THE CONTEXT
Examination may reveal an attic or posterosuperior marginal perforation, a retraction pocket, or pearly-white cholesteatoma flakes.
Perforation and retraction pockets
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The perforation is attic or posterosuperior marginal. A small attic perforation may be concealed by crusted discharge, and a small granuloma may mask the perforation.
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Retraction pockets are invaginations in the attic or posterosuperior pars tensa. Early pockets are shallow and self-cleansing; deeper pockets accumulate keratin and become infected.
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Pearly-white cholesteatoma flakes can be suctioned from retraction pockets.
Stages I and II
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Stage I is mild retraction in which the tympanic membrane does not contact the incus.
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In stage II, the tympanic membrane retracts deeply enough to contact the incus, but the middle ear mucosa is unaffected.
Stage III: Middle ear atelectasis
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The tympanic membrane lies on the promontory and ossicles. The middle ear space is partly or completely obliterated, but the mucosa remains intact.
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The membrane can be lifted from the promontory with a suction tip and balloons up when nitrous oxide is used during anaesthesia.
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Prolonged retraction causes absorption of the collagenous middle layer, making the membrane thin. The long process of the incus and stapes superstructure are also absorbed.
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A ventilation tube helps restore the position of the tympanic membrane.
Stage IV: Adhesive otitis media
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The very thin membrane wraps around the promontory and ossicles and becomes adherent to the promontory. The middle ear space and mucosal lining are absent.
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Retraction pockets may collect keratin plugs and form cholesteatoma. Erosion of the long process of the incus and stapes superstructure is common.