In this section
The formation of
the ear occurs during the first trimester of pregnancy. It arises from six
lumps of tissue called “hillocks” on each side of the embryo’s head. These
then develop into the various parts of the external ear.
A child’s ear
reaches 95% of adult size by the age of six.
Microtia is an
incomplete or abnormally formed ear. It literally comes from the words “micro”
(small) and “otia” (ear). Microtia may affect one side only (unilateral) or
affect both ears (bilateral). Eighty percent of the time it is unilateral. Some
people may have microtia as part of a syndrome known as craniofacial (or
hemifacial) microsomia. In this condition, there may also be a small jaw and
weakness of some of the facial muscles on the affected side. Treacher Collins
syndrome, in which the eyes and facial bones are affected, is also another rare
condition that may be associated with microtia.
Microtia occurs in
around 1 in 6000 births. The chance of an affected parent transmitting this to
their children is usually small (less than 6%), but there are some families who
carry a gene for microtia.
means “hidden ear”. In this condition the upper part of the ear is buried
beneath the skin of the scalp. Usually the cartilage is normal. Reconstruction
involves lifting the ear out from under the skin, creating a groove behind the
upper ear and using flaps of the surrounding skin to cover the ear cartilage.
This is usually done as a day procedure in a single stage.
A lop ear is one in
which the upper part of the ear is bent over. There is often a relative
shortage of skin and the cartilage framework may also be smaller than the other
side. Surgery involves correction of the cartilage using either the cartilage
already in the ear, or sometimes a cartilage graft from the other ear. Skin
cover involves using local skin flaps. When severe, this condition occasionally
requires correction with the use of a rib graft, similar to the procedure for
Microtia and Ear Anomalies in Children, Royal Children’s Hospital Melbourne)
occurs when there is a problem with the development of the ear in the embryo.
The deformity is thought to be due to an abnormality of the blood vessel
supplying the area around the ear in the embryo. This is still uncertain, and
nobody knows what causes this to happen. Occasionally it is due to an inherited
defect, but more often it is a one-off condition that the child with microtia
will not pass on to their own children.
is no evidence that anything a mother does during pregnancy causes microtia.
some cases of microtia the hearing may be normal or partly reduced and not
require any treatment. Patients with microtia may not have an external ear
canal, but this does not necessarily mean that they cannot hear on that side,
as the inner ear may be normal. In others, there may be problems with the
formation of the middle ear which can affect hearing.
with unilateral microtia with absence of the ear canal on that side will often
have problems identifying which direction a sound is coming from.
child will need to have audiograms to test their hearing, and also a CT scan to
look at the small bones in the middle ear to determine whether or not hearing
can be improved in the ear.
CT scan is also used to determine the position of the facial nerve as it passes
through the middle ear. The position of the facial nerve in the middle ear can
also determine if it is possible to reconstruct an ear canal on the affected
side. As any surgery to restore hearing is usually done after reconstruction of
the external ear, a CT scan is often not done until after seven years of age at
which time they may not require a general anaesthetic for the scan.
is important that microtia and other ear deformities are treated by surgeons
specializing in these conditions to ensure the best chance of a good result.
The treatment of microtia needs to address the functional problems (hearing
loss) as well as the aesthetic concerns (how the ear looks). Not all children
with microtia will have problems with their hearing. Your child will be seen in
a special clinic by doctors and health professionals from the following areas:
create a new ear, the choices are either to use tissue from the patient’s own
body (autogenous reconstruction), to use synthetic materials (alloplastic
reconstruction), or a combination of the two. Alloplastic reconstruction is not commonly used at the Royal Children's Hospital.
reconstruction involves making a new ear from the patient’s rib cartilage which
is then placed under the skin on the side of the scalp where the ear should
have been. The ear lobe that is usually present is repositioned into its normal
position. A second operation is required to lift the ear out from the side of
the head and create the groove behind the ear with a skin graft.
alloplastic reconstruction can involve either a plastic clip-on ear
(osseointegrated prosthesis), which attaches to surgically placed studs in the
bone on the side of the head, or the use of a material called Medpor (porous
polyethylene), which is placed under the skin in a similar manner to the rib
cartilage in an autogenous reconstruction. Sometimes your child may require
surgery to pin back the other ear to more closely match the reconstructed one.
answer is probably an autogenous reconstruction using the patient’s own rib,
but in some cases an alloplastic reconstruction may be preferred.
advantage of an autogenous ear reconstruction is that it is more resistant to
trauma, and hence can be treated more like a normal ear after the completion of
surgery. It also has less risks of future infection or exposure than a Medpor
ear. A clip-on osseointegrated prosthesis requires much more long-term
maintenance in terms of keeping the studs clean, and there can also be problems
getting the ear prosthesis to have solid fixation to the head. It is important to
remember that if an osseointegrated prosthetic reconstruction is performed it
is not possible to have an autogenous reconstruction later.
reconstruction can be performed any time from around the age of six years, but
is often deferred until the child requests surgery (8–10 years of age). At this
time the rib cartilage is also large and strong enough to be carved properly
into an ear. Some children are not concerned about their ear deformity and
never request a reconstruction, so it is important that your child is involved
in any decision for surgery.
child will usually be admitted to hospital on the day of the surgery. The
procedure is performed under a general anaesthetic and takes about four hours.
A tracing will be made of the normal ear which will be used to design the
framework for the reconstruction. Cartilage is harvested from the chest wall,
through an incision which is around 10cm long. The cartilage from about three
ribs is removed and carved into a framework which is designed to resemble the
other ear. A drain will often be placed into the chest wound.
on the ear remnants present on the microtic side, some of the parts may be used
to make up some of the new ear, usually the lobule. Most of the abnormal ear
cartilage is removed, and a skin pocket is formed, into which the cartilage
framework is placed. A suction drain is used to encourage the skin to redrape
over the framework, and the skin is closed.
suction drain will be watched closely over the first few days, in order to
ensure the skin sucks into all the crevices of the cartilage. The drain is
removed after four days.
second stage of the ear reconstruction, which involves elevation of the created
ear from the side of the head, is performed several months after the first
incision is made around the back of the new ear, and the ear is lifted up from
the side of the head. Some cartilage from the first operation, which has been
stored in the chest scar, is placed under the ear to help to hold it out from
the head. The new groove behind the ear is covered with some tissue from under
the scalp and then covered with a skin graft to line the new groove with skin.
A drain is placed in the scalp, and dressings are put on.
hospital stay after the second operation is usually shorter (often only
of using rib cartilage to make the ear framework, an artificial framework made
of porous polyethylene (Medpor) can be used. This is covered by the patient’s
own skin and a flap of tissue taken from the scalp. Skin grafts are also used,
but a projecting ear can be made after one operation. Good results can be achieved
but a second operation to add details to the ear will be needed and the
framework may not be as resistant to infection or trauma as a rib
a third procedure is necessary to trim off some excess skin from the ear, or to
perform some minor adjustments to the ear, in order to obtain the best possible
final result. Surgery may be performed on the other ear to help obtain better
final symmetry. Laser hair removal is sometimes done to remove excess hair on
the ear, or to improve the hairline before placing the ear in position.
to reconstruct a new ear canal and eardrum may be attempted in cases where the
inner ear is normal, the middle ear is properly aerated and the overall structure
of the skull around the ear is adequate to allow room for the new ear canal. A
CT scan is performed to demonstrate these anatomical factors.
it is possible, then this is usually done as a separate procedure by the ENT
surgeons, after the reconstruction of the external ear is complete. This
involves creating an opening down to the middle ear, making an ear drum, and
then lining this tunnel with a skin graft. In cases where the structure
(anatomy) of the ear is not suitable for reconstruction of the ear canal and
hearing, an osseointegrated (fixed to the bone) screw fixture can be used to
attach a hearing aid directly to the skull behind the ear. This allows more
effective sound transmission to the inner ear. Placement of the screw fixture
requires a relatively minor surgical procedure.