Hemifacial Microsomia Syndrome
What is Hemifacial Microsomia Syndrome?
Present at birth, hemifacial microsomia is the most common congenital syndrome with the exception of Down syndrome. Hemifacial microsomia occurs with a frequency of one in every 3,500 live births.
Hemifacial microsomia can occur alone or with Goldenhar syndrome (a variant of hemifacial microsomia, with the additional presence of benign eyeball or eyelid tumors). Most often, hemifacial microsomia affects one side of the face (15 percent of the time it affects both sides).
Hemifacial microsomia is also known as oral-mandibular-auricular syndrome, lateral facial dysplasia, otomandibular dysostosis, or first and second brachial arch syndrome.
Hemifacial Microsomia Syndrome Characteristics
Individuals with this syndrome are typically characterized by the following differences:
• underdeveloped lower portion of face (typically, affecting only one side) – imbalanced facial appearance
• underdeveloped lower jaw
• underdeveloped ear/hearing problems
Additional characteristics that may be present include:
• facial skin tags
• a smaller than normal or missing eye on the affected side
• a smaller than normal or missing ear on the affected side
Hemifacial microsomia begins early in pregnancy, while the baby’s head and face are developing. One side of the face grows at a slower rate than the other side. From about six weeks of age and older, the affected side will become more and more imbalanced, visible specifically in the jaw, mouth, outer and inner ear, cheeks, and possibly the eyes. The growth rate difference continues throughout childhood and adolescence, creating further irregularities and imbalances. By the age of 16 to 18 (sooner in girls), the child’s face will reach its full adult size, allowing more extensive and lasting correction.
What is the Cause of Hemifacial Microsomia Syndrome?
The exact cause of hemifacial microsomia syndrome is unknown.
It may occur because an embryonic blood vessel in the baby’s developing face accidentally burst, creating two growth-related problems – a notable slow-down in the blood flow to either one or both sides of the baby’s developing face, preventing those structures from growing at a normal rate; and formation of a group of blood clots, which interfere with growth as well.
Because it is not genetically linked, most cases are sporadic and the risk of an individual with hemifacial microsomia syndrome to have a child with hemifacial microsomia syndrome is minimal – as are the chances of parents who have a child with hemifacial microsomia syndrome to have another child with this same syndrome. There does not seem to be a connection between anything the mother did (or didn’t do) to cause her baby to have hemifacial microsomia syndrome.
Hemifacial Microsomia Syndrome Treatment
When a child is born with a craniofacial issue, we evaluate many factors in order to develop the most effective treatment plan. We study how the child's underlying structures and functions are affected, including: the brain and facial skeleton, the central nervous system, the senses and parts of the spine (cervical vertebrae). In patients whose facial skeleton is affected, we carefully identify resulting changes in the soft tissues of the face, mouth and top of throat (pharynx). It's imperative to quickly determine how their condition is affecting normal, critical functions such as breathing, swallowing and speaking, so that we can promptly begin appropriate treatment.
In most syndromes, the abnormal growth patterns continue throughout the growing years because they were programmed into the body while the embryo was forming. In order to correct and repair the child's areas of concern, we evaluate the anatomical and functional problems and carry the treatment plan out in stages. At each new level of maturity, we'll take advantage of the natural windows of opportunity for reconstruction and other surgical procedures.
We must time each intervention carefully, because when we change or correct part of a child's body, that surgery indirectly affects the body's growth and development "messages." Our broad range of experience allows us to not only identify the most appropriate timing for repairs but to also respond to unpredictable changes as we go.
Essential factors will lead to the best outcome: For our part, accurate diagnosis and a customized, expertly carried-out treatment plan are primary concerns. This applies to reconstructive surgery, as well as aesthetic surgery, to create the very best facial and corporal appearance. For your part, as the parent/family, the outcome depends on your commitment to play the key support role throughout the child's various surgeries, physical changes, social adaptations, academic development and everyday life skills.
In all syndrome conditions, our treatment goals fall into similar categories – to give the child's brain and all sensory organs room to grow and develop, and to make it as easy as possible for the child to breathe, eat, sleep, communicate and become as independent as possible.
Treatment may include jaw surgery, grafting to correct the cheek bones, eye surgery, ear reconstruction, staged orthodontics and hearing aids.