Hemifacial Microsomia

If your child has hemifacial microsomia, the most visible signs of the condition are underdeveloped upper and lower jaws on one side of the face. It may appear that your child's mouth slants upward toward the affected side.

Often the forehead and cheek are flattened on the affected side and one eye socket is smaller than normal.

Other signs of hemifacial microsomia include:

• Ear abnormalities: Small nodules of excess skin around the ear, underdeveloped or absent external ear, underdeveloped or absent inner ear structures, and hearing loss
• Jaw abnormalities: A small or underdeveloped jaw, upward slanted mouth/jaw, appearance of a “crooked smile,” and inability to chew
• Facial findings: Flat cheek and/or forehead, overall facial asymmetry (unevenness), weakness of muscles, and loss of sensation

Rarely, this condition can occur on both sides of the face. This is referred to as bilateral facial microsomia.

Experts do not know the exact causes of hemifacial microsomia. They believe that the condition occurs because of a disrupted process in your baby’s fetal development during the first six weeks of gestation. It is not known if environmental factors are involved.

Hemifacial microsomia is thought to be inherited in some families, because there have been some cases reported where the condition occurs more than once in a family. Researchers have not yet identified the genes involved in hemifacial microsomia.

There is nothing you (or your child’s other parent) did — or did not do — that caused the hemifacial microsomia.

An experienced geneticist — a specialist in disorders resulting from a problem in the genes — is the best expert to diagnose hemifacial microsomia. However, experts do not believe that all cases of hemifacial microsomia are linked to genetics. The geneticist will usually diagnose hemifacial microsomia with a physical examination of your child and by reviewing his or her medical history.

There is no single test for hemifacial microsomia, but several tests may be used to confirm a diagnosis. Possible diagnostic test include:

• x-rays of the head
• computed tomography (CT) scan

The type and severity of hemifacial microsomia is different for every child. The Cleft and Craniofacial Center at Boston Children’s Hospital treats children with all forms of this condition, providing surgical solutions for even the most severe cases.

Some children with hemifacial microsomia will need more procedures and more involved care than others. During infancy, the initial goals are to ensure your baby is breathing and feeding well. Later in childhood and adolescence, the goal is to improve appearance and function of the affected areas.

We develop personalized surgical treatment plans should for each patient. Your child’s treatment team will include a comprehensive team of experts from many specialties. Each specialist on our craniofacial team will collaborate on a treatment plan that meets your child’s specific needs.

Treating facial nerve paralysis: Boston Children’s Facial Reanimation Program

At Boston Children's Hospital, children with facial nerve paralysis caused by HFM receive treatment from a team of doctors with extensive training and experience in restoring the greatest possible degree of sensation and movement to a child’s face.

Our experienced, compassionate team understands that lack of facial expression or facial muscle tone can cause a variety of functional and social problems for your child. That's why we make it our business to offer the latest and best treatments, including:

• Tissue transfer: We transfer soft tissue from elsewhere in the body to increase the fullness of your child’s cheek and forehead.
• Dynamic muscle transfer: If your child has missing facial sensation and mobility, a muscle transfer from one body part to the face can enhance facial expressions and function.
• Microsurgical techniques: Our doctors will try to minimize the side effects of surgery by using techniques that reduce scarring and improve recovery times.
• Fillers: When your child is a pre-teen or teenager — as facial growth is tapering off — artificial “fillers” can be used to add bulk to deficient areas.

Treating jaw abnormalities

Most children with hemifacial microsomia have a significantly underdeveloped upper and/or lower jaw. This can lead to difficulty chewing and keeping the teeth properly aligned. The treatment depends on the extent of your child’s symptoms. Reconstructive surgeries can include:

• Distraction osteogenesis: This is a jaw lengthening procedure during which the surgeon will make a cut in the jawbone and insert a device that will gradually stretch and lengthen the bone over time.
• Bone graft: If the jaw deformity is more extensive, surgeons may take and transfer bone and cartilage from elsewhere in the body and reconstruct the underdeveloped part of your child’s jaw.

After surgery, your child may still have some asymmetry (unevenness) in the appearance of the jaw and some difficulty chewing and biting. Sometimes multiple surgical procedures are needed over the course of many years to enhance appearance and function.

Treating ear abnormalities

Reconstructive surgical procedures for your child’s ear, if needed, will usually start between 6 and 8 years old. Several procedures over approximately one to two years may be needed to construct a missing or severely abnormal ear.

Families seeking the very best care for their child come to the Craniofacial Program at Boston Children’s for our:

• nationally recognized care: U.S. News & World Report ranks Boston Children's Hospital among the best children's hospitals.
• world-renowned facial reanimation program: Children with facial nerve paralysis are treated by team of doctors with extensive training and experience in restoring the greatest possible degree of sensation and movement in a child’s face.
• research and innovation: Our clinicians are involved in research that moves us closer to a better understanding of — and treatment for — all deformities of the head and face.
• customized treatment: Our team will develop a customized treatment plan that meets all of your child’s needs — one that involves you and your family at every step of the treatment.

Our Craniofacial Program includes some of the world’s most experienced craniofacial surgeons, plastic surgeons, oral and maxillofacial (jaw) specialists, dentistry professionals, psychologists, and social workers — all working together to address the many needs of your child and your entire family.

Meet our craniofacial team.