Lengthening of the mandibular ramus by distraction osteogenesis is performed in the same manner as in Pruzansky IIa and IIb patients. For a detailed description of the procedure please refer to the section on hemifacial microsomia.
In younger patients the maxilla may grow vertically (orthodontically assisted) and close the resulting posterior open bite. In older patients a Le Fort I osteotomy may be necessary at completion of the distraction.
If the posterior open bite created by ramal lengthening by distraction is not closed, the mandibular deformity will recur.