by Harry J. Buncke, M.D.

Facial paralysis is a relatively uncommon condition, occurring in one in 4000 people on a yearly basis and seen by specialists of almost every category but more commonly by pediatricians and gynecologists at the time of birth, neurologists and neurosurgeons, trauma surgeons, ENT surgeons, head and neck surgeons, plastic surgeons, internists, and psychiatrists.

It is a devastating condition, particularly since loss of normal facial expression on one side produces an obvious stigma noted by all observers since the exposed face is part of our culture and is our primary instrument of communication.

Loss of spontaneous animation on one side of the face not only produces severe psychological trauma but also disrupts speech, mastication, and eye function. Treatment depends on the cause of the problem and should be instituted as early as possible.

Some individuals compensate for the lack of muscle function by developing an absolute deadpan expression, or by refusing to smile or to move the normal side, in order to disguise the paralysis. Children often develop a withdrawn personality since they are immediately labeled as being "deadpans" or "difficult personality problems. " Older people are regarded as being angry or uncommunicative.

Congenital facial paralysis is not as marked as that seen in adults since the facial tissues and fat in children is quite turgid and does not tend to progressively sag as it does in adults. Interestingly enough, protection of the eye is seldom a problem in young children who seem to have a congenital Bell's phenomenon or closure of the eye with upward gaze.

The paralysis is often incomplete, involving only the muscles to the upper lip or central face. In rare cases, cross-facial nerve grafting to the weakened muscles has been shown to be beneficial. If these procedures fail to achieve success, the same cross-facial nerve graft can be used later to innervate a functional microvascular transplant at another stage.

The primary objective of all facial nerve surgery is to restore spontaneous symmetrical animation. Immediately after trauma or tumor resection, direct repair of the nerve with or without grafts, is feasible and should be considered in all cases. If the paralysis has existed for several months (e.g., after Bell's palsy, basilar skull fractures, or removal of 8th nerve tumors), direct reinnervation is not possible since the muscles undergo irreversible atrophy in 12 months. Procedures using the spinal accessory, the hypoglossal, or the mandibular nerve can produce movement of facial muscles, but this movement is not spontaneous, must be learned, and is seldom synchronized except in studied, planned expressions.

With a long-standing facial paralysis, the best approach is a two-stage combination of several techniques. Branches from the normal hyperactive side are selected from the eye and the upper and lower lip areas and are connected with a cross facial sural nerve graft across the lower lip or under the chin to the paralyzed side. The lower lip route for the graft is used since the upper lip area will be used during the insetting of the muscle during the second stage. Neurotization of this graft occurs at a millimeter per day or at an inch per month and can be monitored by an advancing Tinel sign along the course of the graft. A functional microvascular muscle transplant is then placed in the paralyzed side and innervated by the cross facial nerve at the second-stage operation after the Tinel sign has reached the middle of the paralyzed cheek. Slips of the transplanted muscle are inserted into the upper and lower lids and upper lip.

During the first stage, in addition to the cross facial nerve graft, the anterior centimeter of the temporalis muscle can be turned down into the upper and the lower eyelids to provide a 5th nerve functional fascial sling which helps with eye closure until the muscle transplant procedure. Stability to the sagging side of the lip can also be accomplished at the same time by transferring the coronoid insertion of the temporalis muscle with fascial slings to the corner of the mouth and the upper lip. These initial muscle transfers stabilize the lids and lip so that the functional muscle does not stretch out during the time of reinnervation.

The restoration of perfectly normal spontaneous animation is not possible. However, spontaneous dynamic action around the mouth, the eye, and the lower lip can be achieved with these procedures.

When the patient smiles without being self-conscious, the operation is a success. The physical and psychological stigma of facial paralysis has been conquered. The two enclosed cases demonstrate this type of accomplishment in an adult and a child.

References

Buncke, H.J.: Facial paralysis. In Microsurgery Transplantation Replantation - An Atlas Text. Philadelphia, Lea & Febiqer, 1991.

Rubin, L.R.: Editor. Reanimation of the Paralyzed Face. St. Louis, C.V. Mosby, 1977.

Smith, J.W.: A new technique of facial animation. Transactions of Fifth International Congress of Plastic and Reconstructive Surgery, Melbourne, Butterworth, 1971.