Purpose: Lengthening of the mandible by distraction osteogenesis is the pre
ferred method for treatment of hemifacial microsomia in children. Use of an
intraoral distraction technique and horizontal oblique ramus osteotomy in
such patients is presented.
Patients and Methods: Mandibular ramus lengthening was performed in 11 pati
ents aged G to 12 years with hemifacial microsomia. During the age of mixed
dentition in hemifacial microsomia patients with a hypoplastic mandible, t
he unerupted molars buds are located high in the retromolar region and are
in danger of being damaged by the osteotomy. Therefore, an intraoral approa
ch exposing the mandibular ramus and angle was performed, and a horizontal
oblique ramus osteotomy was made, preserving the inferior alveolar nerve. A
n intraoral device was placed along the ramus, and distraction was started
on the third postoperative day at the rate of 1 mm/d and continued for 2 to
3 weeks or as long as necessary. The device was maintained for retention a
n additional G weeks and was then removed.
Results: Clinically, the face became more symmetric, The postdistraction po
steroanterior cephalometric radiographs demonstrated elongation of the affe
cted ramus and improvement in facial symmetry.
Conclusions: The advantages of this method are that it allows device placem
ent along the ramus, permitting the ramus elongation necessary in treatment
of hemifacial microsomia, that it prevents damage to the tooth buds which,
during the age of mixed dentition, are in a higher position in the retromo
lar area, and that it prevents injury of the inferior alveolar nerve. (C) 2
001 American Association of Oral and Maxillofacial Surgeons.