During hemifacial microsomia (HMF), an important phase of the treatment is
elongation of the hypoplastic mandible, mainly the ramus, at an early stage
. Twenty-two patients with HFM were treated with distraction osteogenesis:
12 with an extraoral device (10 unidirectional and 2 multidirectional) and
10 with an intraoral device. The mean elongation with the extraoral device
was 21 mm, and with the intraoral device was 17 mm, resulting in a more sym
metrical facial appearance. The advantages and disadvantages of both method
s are presented, based on the authors' experience and a review of the liter
ature. The extraoral device permits elongation of a greater distance, enabl
es extraoral control of the vector of elongation, and conserves the genial
angle by working in many directions. The main disadvantages of the extraora
l device are the social inconvenience to the patient and the extraoral cuta
neous scars. Conversely, the intraoral; device is much more socially conven
ient to the patient and avoids residual scarring. However, in 2 patients tr
eated with an intraoral device, an undesired contralateral open bite appear
ed as a result of reduced vector control. The intraoral method should alway
s be considered first because of its previously mentioned advantages. Howev
er, in severely hypoplastic patients, when three-dimensional correction and
gonial angle control are necessary, or when there is a limited space along
the planned distracted bone, the extraoral device has an advantage over th
e intraoral device.