In general, hemifacial microsomia refers to under-development of one side of the face, with resulting asymmetry. Specifically, the skull, ear, upper and lower jaws, and soft tissues, including the nerves that help move the facial muscles, may be affected. hemifacial microsomia occurs on a spectrum of deformity, from very mild, with only subtle changes, to very severe, with all of these parts of the face and skull being affected. hemifacial microsomia may also be called Goldenhaar’s Syndrome, Oculo-auriculo-vertebral Sequence, and First and Second Branchial Arch Syndrome.
Typically, patients with hemifacial microsomia have a small or absent ear (microtia) and a small upper and lower jaw on the affected side of the face. This causes a slanted or crooked smile, slanting upward toward the affected side.
Is this condition painful?
No, hemifacial microsomia does not cause your child any discomfort.
How common is hemifacial microsomia?
Hemifacial microsomia is one of the most common craniofacial anomalies, occurring in approximately one out of 5500 newborns.
What are the different types of hemifacial microsomia?
As mentioned above, there is a spectrum of deformity in hemifacial microsomia. This may range from a small, abnormally-shaped, or absent ear only or just a minor facial asymmetry to involvement of all of the bones and soft tissues on the affected side of the face. The facial nerve, which is responsible for the movement of the face, may also be affected in more severe cases.
Because there is such a spectrum of deformity, it can sometimes be difficult to diagnose hemifacial microsomia. That is why evaluation by a multidisciplinary craniofacial team is important, so that the craniofacial surgeon, geneticist, and other specialists can all provide their opinions. Special x-rays of the facial skeleton and computerized tomography (CT or CAT) scans are usually obtained to help with diagnosis and treatment planning.
What causes hemifacial microsomia?
Hemifacial microsomia may occur sporadically-that is, as a new diagnosis with no family history-or it may be inherited (“genetic”). When it is inherited, hemifacial microsomia may occur as an autosomal dominant condition, in which there is a 50% chance of having a child with hemifacial microsomia; as an autosomal recessive condition, in which there is a 25% chance; or as a multifactorial condition, in which environmental factors as well as genetics play a role. Even in inherited cases, the severity of hemifacial microsomia is not constant, because there is a spectrum of deformity; one relative may be severely affected while another has only a very subtle manifestation. This phenomenon is known as variable expression.
Ultimately, it is thought that the blood supply to the affected side of the face may be damaged or disrupted in utero, and that this is the cause of the underdevelopment on the affected side.
What are the main issues related to hemifacial microsomia?
Most commonly, patients with hemifacial microsomia have the following problems:
- facial asymmetry
- orthognathic (dental and jaw) problems due to the asymmetry
- microtia (small or absent ear)
Are there other problems that occur with hemifacial microsomia?
Because there is such a spectrum of deformity with hemifacial microsomia, other problems may arise. These can include under-development of the orbit (the eye socket), under-development of the cheek bone, facial paralysis, and severe thinning of the soft tissues of the cheek.
What is the treatment for children with hemifacial microsomia?
While every patient is treated individually, with treatment plans made specifically for him or her, some generalizations are possible. Usually, treatment for hemifacial microsomia must address the asymmetry of the jaws, the small/absent ear, and occasionally the soft tissues of the cheek. The exact nature and timing of the procedures depends upon the severity of deformity in each specific case.
When the jaw deformity is very severe, a rib bone and cartilage graft can be used to reconstruct the deficient side of the mandible. In less severe cases, the deficient side of the mandible can be stretched or lengthened by the technique of distraction osteogenesis, in which the bone is cut and a device is place on the bone to slowly lengthen it. In either of these situations, a repeat jaw surgery will be required in adolescence to achieve a normal relationship of the teeth of the upper an lower jaws. In the mildest cases, an operation is done in adolescence on the upper and lower jaws to correct the facial slant and the jaw asymmetry.
Ear reconstruction is begun after age 6 years. The child’s own rib cartilages are used to build an ear, which is then placed in the appropriate position on the side of the head. This complex reconstruction is done in three or four staged procedures.
A variety of methods may be used to correct asymmetry of the soft tissues of the cheek. These can vary from simple interventions, such as the placement of soft tissue fillers as are used in cosmetic surgery, to very complex procedures that involve transplantation of tissue from another part of the body to the face./p>
What sorts of specialists will be involved in my child’s care?
The optimal treatment of children with hemifacial microsomia is achieved in a multidisciplinary setting. As noted above, these children may have a number of issues that must be addressed. Usually, the specialists involved include:
- the geneticist, who helps assign a diagnosis and counsels the family regarding the possibility for recurrence in future children
- the craniofacial surgeon (a plastic surgeon who has done additional specialized training), who does most of the operations
- an orthodontist, who helps to assess facial growth and development of the teeth, and aligns the teeth
- an otolaryngologist (ENT), who can address hearing problems or perform middle ear surgery if necessary
- a pediatric ophthalmologist, who can assess vision and movement of the eye
- a developmental pediatrician, who can follow the child’s physical and mental development
- the pediatric plastic surgery nurse, who is instrumental in coordinating care and counseling and educating families
Will we get to know our surgeon?
Because children with hemifacial microsomia usually require a number of procedures during the course of their childhood and adolescence, the patients and their families often develop very close relationships with their surgeon and other members of the treatment team. For the surgeon, it is very rewarding to watch these children grow up and to help them along their way through these surgical interventions.