What is Hemifacial Microsomia (HFM)?
Hemifacial Microsomia is a condition in which the tissue on one side of the face are underdeveloped, affecting primarily the aural (ear), oral (mouth) and mandibular (jaw) areas. Sometimes both sides of the face can be affected and may involve the skull as well as the face.
Other terms you may see for this condition are "Goldenhar syndrome", "First and second branchial arch syndrome," "Facio-ariculo-vertebral syndrome (FAV)"; "oculo-auriculo-vertebral spectrum (OAV)".
Are there different types of HFM?
The deformity in hemifacial microsomia varies greatly in the degree of seventy and in the area of the face involved. The disorder varies from mild to severe. In the more severe cases the following structures are underdeveloped: The external and middle ear, the side of the skull, the thickness of the cheek tissue, the upper and lower jaws, the teeth and some of the nerves that allow facial movement. In the milder forms, only some of the structures are affected and to a lesser degree.
What is the cause of Hemifacial Microsomia?
The cause is unknown. Most cases are sporadic, but there often is a familial pattern. Within families the severity varies.
Which parts of the facial bone are involved?
One of the most obvious problems in hemifacial microsomia is the underdevelopment of the upper and lower jaws on the affected side. It may appear that your child’s mouth slants upward toward the involved side.
Often the forehead and cheek are flattened on the affected side with one orbit (eye socket) smaller than normal.
What other areas are affected?
Your child may have unequal cheek fullness (asymmetry) because of the underdeveloped fat and muscle. Some parts of the face may not move normally, which may cause a "crooked" smile. There is a wide range of ear abnormalities associated with HFM. Your child may have a mildly mishapen ear or almost complete absence of the external ear (atresia). Small tags of skin may also be present in front of the ear(s). Occasionally the central nervous system is affected, causing parts of the face to not move symmetrically. (equally)
How is HFM diagnosed?
HFM is typically diagnosed after a comprehensive medical history and physical examination by a Geneticist. There is not a blood test to diagnose HFM. Because the spectrum of severity is so wide, the diagnosis should come from an experienced geneticist with craniofacial expertise. CT studies and x-rays of the face may also be ordered for accurate diagnosis.
What treatment is involved?
Specific treatment is extremely variable because there are so many differences in the types of HFM. Any child with suspected HFM should be evaluated by a Craniofacial Anomalies Team. Each of the specialists will have a proposed treatment plan depending on the severity of your child’s specific physical findings.
What are some of the possible treatments my child may require?
In patients with severe underdevelopment of the lower jaw, reconstruction using a bone graft taken from the ribs may be suggested. Another possiblity would be lengthening the underdeveloped mandible using a bone distraction device. This technique avoids the need for bone grafts. Additionally, the external ear is usually reconstructed between the ages of 6-8 years. Further surgery on the soft tissue of the cheek, or jaw surgery may be needed in the teen years.
Why should my child be seen by a CFA team?
Because hemifacial microsomia involves so many areas of the body, many specialists are required. The craniofacial surgeon performs the jaw surgery and ear reconstruction. The geneticist counsels the patient and family regarding the recurrence risks of hemifacial microsomia. The nurse coordinator acts as a liaison between the family and many specialists and assists in patient education. The ophthalmologist evaluates vision and eye movements. The orthodontist follows the jaw growth and alignment of teeth to assist the surgeon in an optimal result of jaw surgery. The otolaryngologist assesses hearing abnormalities and coordinates middle ear surgery or hearing aides if needed. The speech therapist evaluates the speech development and coordinates speech therapy if necessary. The social worker assists the family in obtaining resources and referrals in their community.
