All people have asymmetric faces. When one looks closely, these differences become more apparent. However, there are conditions in children in which the normal minor differences are much more significant.
Children born with this congenital condition have one half of the face that didn't develop as well as the other. It occurs during fetal development.
Common affected areas:
Ear: Anything from a change in shape to an absent ear
Ear canal: May be absent with decreased hearing as a result
Lower jaw (mandible): Less growth, chin point to side of decreased growth, and abnormal bite
Facial movement: A single nerve (facial nerve) with many branches controls facial movement, and one or more of these may be affected
Eye socket and/or eye: May be small or absent. Whatever the child is born with, he/she will maintain, but it will not get worse with growth.
These children are cared for by a craniofacial team, including a pediatric plastic surgeon, ENT surgeon, speech therapist, dentist, and orthodontist. Surgery may be needed to help the jaw grow and to reconstruct the ear. Why this condition occurs is not fully understood, although genetic and environmental factors are both likely.
Congenital Facial Nerve Palsy
On each side of the face, there is one main facial nerve with several branches that travel to the muscles of facial expression. Children can be born with a deficiency of this nerve, usually on one side. Sometimes both nerves are affected. This is a rare problem.
The causes of congenital facial nerve palsy are usually birth trauma or developmental.
Developmental: When one side is affected, it is typically seen as muscular weakness, with difficulties raising the eyebrow, closing the eye, feeding difficulties, or smiling on the affected side. A bilateral (both sides) form of this problem is known as Mobius Syndrome. Mobius syndrome is a congenital paralysis of the muscle of facial expression, usually due to deficiency of the facial nerve as well as one of the nerves controlling movement of the eye.
Birth trauma: 90% of the cases related to birth trauma will improve without treatment. If it does not go away spontaneously, then based on the location of the nerve damage, a surgical procedure called a neurorrhapy (stitching nerve ends together) or nerve graft may be performed to restore normal nerve function.
Aside from the inability to communicate to others with facial expression, children with facial nerve weakness/paralysis may have difficulty closing the eye on the affected side, and thus have eye irritation and/or corneal ulceration. Prolonged exposure can lead to infection or loss of vision.
There are two forms of treatment:
Eye protection: A small weight is surgically placed into the upper eyelid on the affected side. This will make it easier to close the eye, with the goal of keeping the cornea protected, and the eye free of infection.
Smile recreation: The ability to smile can be restored either by transferring one of the surrounding muscles of the face to the corner of the mouth, or by implanting a new muscle taken from another part of the patient's body. With new muscle, arteries, veins, and nerves must be reconnected under a microscope to restore function. The nerve that powers the new muscle comes either from a chewing muscle on the same side of the face or from a normal facial nerve branch on the patient's other side.
Acquired Facial Nerve Palsy
Children can develop facial nerve weakness/paralysis during life due to trauma, tumors, or from a third condition called Bell's palsy. Bell's palsy is thought to result from a viral infection that affects the facial nerve, and therefore often results in a unilateral (one-sided) facial paralysis. With time, the nerve can regain function. Many children get full function back, while others regain only partial function. In the case of no return of function, treatment can be offered as described above for congenital cases.