Facial paralysis is a condition that may be present at birth, such as Moebius syndrome, or it may be acquired later in life, such as following removal of facial tumors near the nerves that move the facial muscles. Bell’s palsy is the sudden onset of facial paralysis and is felt to be viral in origin. Because Bell’s palsy is usually self-limited, plastic surgeons only become involved if the condition does not show improvement after three months or more.
Moebius syndrome is a rare condition caused by the absence or underdevelopment of the 6th and 7th cranial nerves, which control eye movements and facial expression. Other cranial nerves may also be affected, including the 3rd, 5th, 8th, 9th, 11th and 12th. Moebius syndrome typically affects both sides of the face.
Depending on which nerves are affected, the following are some of the possible symptoms:
There is no specific course of treatment for Moebius syndrome. Treatment is supportive and in accordance with symptoms. This supportive care may include the following:
Plastic reconstructive surgery may be beneficial in some individuals.
Surgery can be used to improve the function of the affected muscles in facial paralysis. Two approaches by which plastic surgery can help to correct the conditions associated with facial paralysis are either static or dynamic. Static procedures include soft tissue slings to suspend the tissue around the mouth and gold weights to help with eyelid closure. Dynamic procedures consist of muscle and nerve transfers to bring new muscles in to replace the paralyzed muscle, with a particular focus on muscles for smiling and facial expression. Depending on the needs of the patient, a combination of static and dynamic procedures can be used.
Static slings — These procedures use the patient’s own tissue to bring up the sagging portions of the face. These slings may be applied to the portion of the face that produces a smile. Static slings are designed to improve facial balance but do not reanimate the paralyzed muscles. Examples of static procedures that are helpful to patients include placement of gold weights in the eyelid to help the closure and prevent eye dryness and irritation.
Dynamic muscle transfers — Dynamic procedures attempt to reanimate the face by substituting other muscles for the non-functioning or missing facial muscles. The muscles selected for transfer can either be local muscles, such as those used for chewing, or muscles from a distant part of the body such as the leg or chest wall. Distant muscles are transferred with a nerve and blood vessel and connected to a nerve and blood vessel in the face using microscopic surgical techniques. The transferred muscle can either be connected to the nerves from the unaffected side of the face that normally fires during smiling, or to nerves that control chewing if these are not paralyzed. After surgery, physical and occupational therapy with biofeedback techniques are used to train patients when and how to activate the new muscles of smiling. Children do very well with this process, and often learn to smile without thinking about it after a period of time.