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Mandibular distraction osteogenesis: pron. man-dib-u-lar dis-track-shon osti-oh-jen-esis
Jaw distraction is the name for a surgical method of lengthening a small or
recessed (hollow or indented) jaw. A small or recessed jaw can cause severe or ongoing difficulty with
breathing. The procedure involves surgical insertion of distraction (lengthening) devices into the jaw. These devices allow the jaw bone to be lengthened. In most
cases, as the jaw is lengthened, the airway opens up and allows the
child to breathe clearly.
This procedure is only used in cases of severe,
life-threatening breathing problems. It has been very successful in
easing airway obstruction and has prevented the need
for tracheostomy (pron.
track-e-os-tomi) in most cases.
Signs and symptoms
Some children are born with a very small or recessed lower jaw.
In most cases this does not cause any problems at all, but in a
small number of infants it can cause serious problems in
the first few months of life. This is mostly due to the tongue
moving back into the throat when the child breathes in. The tongue then partly or
completely blocks the airway. This is known as upper airway
obstruction and can cause serious disruption to breathing and
If it it seems that your child may have upper airway obstruction, they will need to stay in hospital for a period of time
in hospital so that further tests can occur and their breathing can be monitored and assessed. During this time, non-surgical methods of improving the
airway obstruction will be tried. These methods can include positioning or insertion of a
nasopharyngeal (pron. nay-so-far-ran-jeel) tube.
In a very small number of cases, these non-surgical methods are
not successful and a child's breathing problems become life threatening. Sometimes, the non-surgical methods may be required for extended periods of time, and this can be very difficult to sustain. If either of these things happen, jaw
distraction might be the best treatment.
If your child has severe or persistent upper airway obstruction, one or
more of the following tests will be done to decide
if the jaw distraction procedure is appropriate:
The decision to perform a jaw distraction procedure is made by a team of medical and surgical staff with a variety of specialist expertise. Each
member has skills and experience in various aspects of airway
obstruction. After considering the results of the tests, the
team will decide if jaw distraction is appropriate for your child. Jaw
distraction will not be considered for an infant to correct facial
dimensions alone, but is only used to improve airway obstruction.
The surgery takes approximately two to three hours. Your child will need to stay in hospital until their airway has opened up and they are breathing clearly and without assistance.
An incision is made through the skin under the jaw line, and
then the jaw bone is carefully sectioned to enable a distraction
device to be attached to either side of this separation in the
bone. This happens on each side of the jaw.
The distraction device is not visible after the operation except
for two small rods that will protrude out from the chin or from
behind the jaw line. These are called the distractor arms, and this
method of distraction is called internal mandibular distraction (Figure 2).
The day after surgery, each distractor arm will be turned a full
360°. This separates the pieces of bone by 0.5mm. This procedure is
repeated every eight hours for approximately 10 days. During
the eight hours between turns, your child's jawbone will grow to fill the
This gradually makes the jaw bone longer, which will move the tongue
away from the back of the throat. This in turn makes the airway larger, and breathing will become easier (Figure 3).
The distraction device will stay in place for a period of time to support the new bone as it gains more strength. This will occur over the six to
eight weeks (approximately) following surgery. During this time your
child can be at home and will be breathing and feeding normally.
The distraction device is removed once the bone is strong enough. This involves another surgery, and your child will need to stay in hospital for another one or two nights.
The risks involved in a jaw distraction procedure are very small. The risks of either a tracheostomy or leaving an airway obstruction untreated are much higher.
There are potential risks in all surgery. However, in our
experience these have been rare or extremely minor. The risks specific to jaw distraction include
infection, sensory disturbance in the face, damage to molars
or faint scarring.
Once jaw distraction is complete there should not be much disruption to daily life. You can still feed your child
normally. A little extra care taken to keep the area around the
distractor arms clean will help prevent an infection. The distractors are made of flexible titanium and there should not be a problem if they are knocked or grasped by your child.
Follow up appointments will be made with the various doctors and surgeons
involved in the jaw distraction process during your child's stay in hospital.
If you have any problems with the distraction device, or if you notice any signs of infection such as redness, pain or swelling, you should contact the
hospital's Plastic & Maxillofacial Surgery department (T) 03 9345 5522.
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