Overview

      Hemifacial microsomia (HFMS) is the second most common facial birth defect. Its exact cause is undetermined at this time; however, researchers believe a disruption in the blood supply to the jaws in the first trimester may produce HFMS.Children with HFMS are born with a deformed mandible (lower jaw). The jaw deformity is characterized by an asymmetry of the mandible secondary to a failure of one side of the mandible to grow. Additionally, the failure of the mandible to grow produces an accompanying deformity of the upper jaw (maxilla) on the same side. As the child grows the deformity becomes more noticeable as the chin is off to the affected side & the child’s “bite” is off centered. The degree of deformity varies with each child.

      Since HFMS produces a defect of the hard (bone) and soft tissue, facial asymmetry is noticeable in even minor cases and often accentuated in the most extreme cases.

      Accompanying findings of patients with HFMS include a missing ear, hearing loss, weakness of the facial nerve, and abnormal orbit size.

Treatment

Treatment of HFMS

      The treatment of children and adults with this condition varies with each case and should be tailored to each patient’s particular needs.Years ago the standard of care was to take a rib from the patient and graft it to the affected side. As the patient grew, so did the rib. Many times this worked well; however in a significant number of cases the rib either grew faster or slower than the jaw producing an asymmetric jaw.

      Today surgeons have an alternative to the rib graft procedure: Distraction Osteogenesis Surgery (DOS). In DOS the patient’s deformed bone is surgically cut then a small distraction device is affixed to the bone.

      After a week of healing the distraction device is activated daily and the two bone segments are slowly separated. Once the distraction process is completed a consolidation period takes place where the bone grows in the gap created by the separation of the two bone segments. After the bone has sufficiently regenerated the distraction device may be removed. Advantages of DOS in treating HFMS include:

• Suitable for children & adults
• Generation of bone and soft tissue
• Minimally traumatic surgery
• Elimination of the need of bone grafting

      DOS has been shown to successfully address the reconstruction needs of patients with HFMS. Although long term follow in DOS for HFMS is currently unavailable, but results thus far are encouraging.In addition to DOS to reconstruct the facial bones patients will need the skill and care of a qualified Plastic & Reconstructive surgeon to address the missing ear, which occurs with HFMS.

      The general dentist and orthodontist are also valuable members of the team in these patients. Both of these dental professionals will work with the Oral & Maxillofacial surgeon to ensure that the appropriate dental and skeletal relationship will be obtained as treatment is completed.

Questions

Questions

If you have any additional questions about Hemifacial Microsomia you may contact Dr. Whitesides at drlwhitesides@atlantaoralsurgery.com.