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Hemifacial Microsomia: Treatment
The Jaws
There are two basic approaches to centering and balancing the face. Currently,
the most commonly recommended technique is to use distraction. I typically
do not recommend the distraction technique at my center for a number of
reasons which are listed below. The distraction technique involves making
an osteotomy (cut in the bone) across the mandible (lower jaw) and attaching
a metallic screw driven device to either side of this osteotomy. Pins
are usually put through the skin into the bone, and the expansion device
is attached to these pins. By turning a screw on the expansion device,
a little each day, the bone slowly gets longer. There are also devices
that are completely buried under the skin, except for a small metal bar,
which pokes outside so that the screw can be turned. These distraction
devices have been proven to successfully lengthen bone, and many doctors
treating hemifacial microsomia recommend them. However, these devices
are never used at the Craniofacial Center in Dallas for treating children
affected on just one side, and only vary rarely for bilateral cases. There
is a long list of reasons why I chose not to use these distraction devices:
- The overall complication rate for using these devices is about 1
out of 3 cases, as published in a survey of doctors. The complication
rate was over 50% for doctors who had done fewer than 10 patients! Surveys
typically underestimate complication rates, so that the actual complication
rate may even be higher.
- These devices leave scars on the child's face that cannot be removed,
and remain for a lifetime. Many doctors say that the scars will fade
away and not be noticeable. I recommend seeing another child's scars
first (in person, scars tend to not show up in photographs) before allowing
this procedure to be done. There is an internal distraction device that
does not leave facial scars, but this device has an even higher complication
rate than the external device.
- The lower jaw may be lengthened in one direction with distraction,
but distraction cannot widen the face. So, after distraction is done,
the chin will line up nicely in the center of the face, but the side
of the face will be even flatter. I believe that the use of distraction
causes more children to require adding additional soft tissue to the
face to help balance it. Rebuilding the facial skeleton (described below)
reduces the need for additional operations to build up the soft tissues
of the face.
- The teeth usually fit together fairly normally before using a distracter.
However, after distraction, with one side of the lower jaw longer, the
teeth will not line up with the other teeth. The result is that extensive
orthodontia will be required, and eventually surgery may be needed to
correct this problem.
- In order to attach the distracter to the jaw, it is necessary to
use metal pins or screws. It is very likely that the front pins or screws
will go through the child's un-erupted permanent teeth. The result is
that the permanent tooth will not come up and the child will need an
artificial tooth (or multiple artificial teeth).
- The upper jaw is not treated by distraction. This means that after
the two operations are finished, one to put on the distracter and one
to take it off, the upper jaw is still too small on the affected side,
and will frequently need surgery to correct it.
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The alternative to the use of distraction is a single-staged orthognathic
procedure. From inside the mouth (so there are no scars on the face
except for a short scar just in front of the ear) the upper and
lower jaws may be cut and moved into a better position and, if necessary,
an absent TMJ can be rebuilt using the child's own rib. It is best
to delay this surgery until the child is older and wants to have
the surgery done. This operation is longer and more complicated
than putting on a distracter, and not every doctor is able to do
this procedure; but the final result is that both jaws are aligned
in the middle of the face in just one operation.
This single-staged operation is not a "perfect" operation. There
is a possibility for an infection afterwards (about 10% chance)
that may require a small operation to treat. If this operation is
done at a very young age, there is a good chance that it may need
to be repeated when the face is finished growing sometime around
16 to 18-years old. Overall, weighing all the positives and negatives,
the single-staged correction is the best treatment, at the lowest
risk.
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Early
Non-Surgical Treatment | Ear
Reconstruction
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Hemifacial Microsomia
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