Hemifacial microsomia (HFM) is a condition where half of the face (“hemi”) is underdeveloped or smaller than normal (microsomia). It is sometimes referred to as oculo-auriculo-vertebra spectrum. The affected side of the face does not grow normally, and it can range from a mild to severe deformity.
Hemifacial microsomia always includes underdevelopment of the lower mouth and jaw (mandible) and can also affect the ear on the same side. It may also involve the eye, cheek, neck and other parts of the skull. Abnormalities in teeth and delays in tooth development can also be seen, and some people may have a small tongue or a large mouth. The muscles and nerves of the face may not move symmetrically resulting in an uneven smile. It can also affect the nerves and soft tissues of the face.
The mildest cases of HFM can present with a slightly smaller jaw and a skin tag near a normal appearing ear. In more severe cases, the face is significantly smaller on one side and they will have an abnormal or even absent ear.
Types of Hemifacial Microsomia
The severity of HFM is typically classified using an OMENS classification:
- Orbit: The orbit (eye) may be smaller or underdeveloped. In some severe cases, the eye may be absent and vision may be impaired. There may be growths on the eye.
- Mandible: The upper or lower jaw bones (or both) are small on one side. One corner of the mouth may be higher than the other. Some people may not be able to fully open or close the mouth. The jaw can appear crooked and even the teeth may be involved.
- Ear: The external ear may be small, abnormally shaped or absent. The internal ear canal is also impacted and the child may have partial or total hearing loss. Skin tags may be present near the ear on the affected side.
- Nerves: Impaired nerve function can range from mild weakness to full facial paralysis.
- Soft tissues: The forehead and cheekbone may appear flattened, the cheeks may appear unequal and the mouth may appear asymmetric.
HFM is the second most common facial birth defect (after cleft lip and palate). It occurs once in every 3,500 to 4,000 births. It is not known why HFM occurs. It may be due to a poor or damaged blood supply to the baby’s face early in the pregnancy. It does not occur because the mother made any mistakes during pregnancy. HFM is not inherited for most people with that diagnosis. An adult with HFM has roughly a 3% chance of their child being born with HFM. The areas of the face affected at birth will remain the same throughout your child’s life and does not worsen over time.
Goldenhar syndrome is a severe form of HFM. It is a rare condition, which includes hemifacial microsomia, dermoid cysts of the eye, and colobomas (clefts) of the eyelid, and other spine anomalies dermoid cysts (epibulbar and lipo).
Testing for Hemifacial Microsomia
Your physician may recommend imaging studies (X-rays or CT scan) to better understand your child’s bones and to make recommendations for treatment.
Treatment for Hemifacial Microsomia
Each child is unique and the treatment options for HFM can vary greatly for each patient. The treatment plan for your child is determined by a team of experts at Hasbro Children’s Hospital. Our craniofacial team includes a craniofacial plastic surgeon, otolaryngologist (ear, nose and throat specialist), speech pathologist who specializes in swallowing/feeding and speech problems, oral surgeon, dentist, orthodontist, ophthalmologist and geneticist to provide comprehensive care for your child.
When a child is first born, the team will assess your baby’s breathing (if the jaw is severely infected) and feeding (if your child has difficulty coordinating sucking and/or swallowing) and will provide support if needed. As your child with HFM grows, additional treatments or surgical procedures may be offered based on the areas of the face affected.
Specific Facial Area Treatments
If your child has a cleft lip and palate associated with HFM, your child will receive feeding support. The lip is typically repaired at three months of age and the palate is repaired closer to one year of age.
Our team otolaryngologist will assess and develop a plan to improve your child’s hearing, often using a hearing aid. Children with abnormally shaped or absent ears may undergo reconstructive surgeries to make the ear appear more normal.
Children may have asymmetry in the size and position of the eyes. Some children may have a dermoid cyst near the eye that can impair muscle function. If the eyelids are involved, surgery may be performed to reconstruct the eyelid.
The muscles of the palate and the muscles/nerves of the face may not move symmetrically. A speech pathologist will assess and treat patients who are at risk for speech problems.
One side of the face is usually flatter than the other side. Your child may benefit from fat grafting or tissue transfer surgeries to treat soft tissue deficiencies to balance facial appearance.
The jaw is typically smaller on the side affected by HFM. If your child is missing bone, they may be offered surgical procedures to lengthen the mandible (jaw) bone or reconstruct the bone by using a bone graft.
If your child has HFM that involves the cervical spine, kidneys, or heart, the craniofacial team will refer your child to other pediatric experts at Hasbro Children’s Hospital.