Diseases Of The Nose Throat And Ear

CHAPTER 54
THE EXTERNAL ACOUSTIC MEATUS

ACQUIRED ATRESIA

Cases of meatal atresia which may take the form of webs, contractures or
thickening of the epithelial lining are the result of infection, injury or surgical
procedures involving the walls of the meatus. Web formation which occurs
at the isthmus or within the bony segment of the meatus is usually associated
with recurring attacks of otitis externa. Complete obliteration of the canal
lumen due to fibrous tissue proliferation produces a varying degree of con-
ductive deafness. Excision of the web may be necessary after the active
infection has been removed by topical applications, exposure being obtained
through an endaural incision. Skin-grafting of the raw area is not necessary.
A gauze mesh pack impregnated with petroleum jelly (Sofratulle) promotes
re-epithelization.

Injuries to the meatus are sometimes followed by thin membrane forma-
tion which is easily destroyed by application of a silver nitrate bead.

Contracture of the introitus of the meatus may result from burns and
lacerations, and a stenosed meatus may follow mastoid surgery. In these
cases a meatoplasty provides the most satisfactory restoration of an adequate
meatal opening. Narrowing of the external orifice of the meatus is also
seen in old age and deafness may result from quite small accumulations
of wax.

Hypertrophied skin lining of the meatus is encountered in association
with chronic otitis externa which is often secondary to chronic otitis media.
The meatal swelling may be sufficiently reduced by packing the meatus with
ribbon gauze wicks soaked in 8 per cent aluminium acetate solution to
permit examination of the tympanic membrane in order to exclude middle
ear disease. If this cannot be excluded the patient will require radiological
examination and possibly mastoid surgery with a suitable meatoplasty.

IMPACTED WAX

The accumulated secretion from the ceruminous glands situated in the outer
part of the meatus may form a solid, often hard, mass giving rise to deafness
and discomfort in the ear. Tinnitus and disturbance of balance may occur
from pressure of the wax on the drumhead, and a cough reflex due to stimu-
lation of the auricular branch of the vagus has been described. The onset of
deafness is often sudden following washing or bathing when the entrance
of water to the meatus closes a previously narrow passage for the trans-
mission of sound by causing the wax to swell and a more profound blockage
results.

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