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Microtia
Microtia
refers to an absence or underdevelopment of the external ear
with or without development of an ear canal (Aural Atresia).
Both of these conditions can occur by themselves in otherwise
healthy children, or as part of a syndrome (e.g. Treacher-Collins
or Goldenhar's syndrome). Microtia and aural atresia can affect
one ear or both and can be associated with normal or abnormal
inner ears. In many cases, children with microtia and/or aural
atresia have normal inner ears and subsequently have normal
"nerve" hearing levels. However, if children do
not have an external ear and patent ear canal, then sound
is physically blocked from reaching the inner ear and the
child demonstrates what's called a "conductive"
hearing loss. To further complicate matters, children with
microtia, and to a lesser extent aural atresia, are faced
with difficult social problems due to their different appearance
as well as difficulty hearing. The CHDR has established a
program to provide comprehensive care for children with these
complex medical problems. Our management philosophy centers
first on restoration of functional hearing whenever possible
and then on aesthetic reconstruction of the ear so that a
child's self-esteem and confidence are improved to allow normal
social interaction and maturation.
Microtia
includes a variety of outer ear developmental defects - ranging
from mildly underdeveloped ears to complete failure to form
any sort of ear structure. The degree of hearing loss and
other developmental defects often coincides with how severe
the outer ear malformation is. The better developed the outer
ear, the better developed the middle and inner ears usually
are. Being a fairly obvious congenital problem in most cases,
microtia is typically detected at birth and the child referred
for an initial evaluation by an ear specialist. Our primary
concern is functional hearing in children. Therefore, a hearing
test is usually performed early on in the process. In cases
of unilateral microtia (one ear affected), the unaffected
ear commonly has normal hearing. However, it is necessary
to confirm that the child has at least one normal hearing
ear so that the child can remain on track for normal communication
skills development. If both ears are affected (bilateral microtia),
then earlier intervention is indicated so that the child is
given the chance to develop hearing and speech. CT scans of
the ear region are obtained after the 1st year of life in
order to determine whether the inner and middle ear structures
have formed properly. (Although scans can be obtained at any
time, since no interventions would be recommended so early
in infancy, no reason exist to obtain a scan earlier than
1 year of age). If the scans show a normal inner and middle
ear, and hearing tests confirm normal nerve hearing levels,
then the child is typically considered a good candidate for
a hearing restoration type procedure. This would typically
involve creation of an outer ear, ear canal and eardrum. However,
this typically involves a lengthy 4 stage procedure in the
case of a permanent autologous reconstruction, or 2-3 staged
procedures with a prosthetic reconstruction. Several considerations
need to be weighed in deciding which options are best for
any given child and their family. Below are discussed the
two reconstruction options offered at the CHDR along with
the relative advantages and disadvantages. It should be noted
that both surgical options are normally delayed until the
child reaches 5-6 years of age. The rationale for waiting
is that a child's outer ear is adult size by the time the
child reaches this age range. Since a reconstructed ear does
not grow like a normal ear has to be modeled upon the opposite
ear for a symmetric appearance, performing the surgery any
earlier would result in an asymmetric appearance. Waiting
any later tends to cause more social problems as children
enter elementary school at an age where other children are
more observant of physical differences.
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