Presented by: Sam P. Most, MD, FACS
Chief, Division of Facial Plastic and Reconstructive Surgery
Associate Professor, Departments of Otolaryngology, Head and Neck Surgery and Surgery (Plastic)
Stanford University Medical Center
February 26, 2009
- The facial nerve structure is highly complex. Damage to just one nerve can cause paralysis and difficulties with speech, eating and drinking, nasal obstruction, visual obstruction, eye irritation and blindness.
- Facial nerves have the ability to regenerate, but the process can take between 12 and 18 months.
- There are a number of surgical techniques to bring movement and functionality to patients with facial nerve damage and paralysis.
Facial nerves give us the ability to show emotions. They allow us to move our eyes, lips, and nose. And they give us the ability to produce tears and saliva. In fact, they are at the very heart of human expression, according to Stanford facial plastic and reconstructive surgeon Sam Most, MD.When something damages one of the many nerve fibers that extend from the brain stem throughout the face, it can be devastating for patients on a number of levels, explained Most, Chief of the Division of Facial Plastic and Reconstructive Surgery and Associate Professor of Otolaryngology – Head and Neck Surgery at Stanford. In a presentation for the Stanford Health Library, he impressed upon the audience the intense psychosocial and functional effects people experience with facial nerve paralysis. And he offered hope to sufferers in his discussion of new treatment options to bring movement and normalcy back to a paralyzed face.
When paralysis occurs on one side of a face, there’s a disharmony between the paralyzed and non-paralyzed sides, he said. Patients express dismay at going out in public. They have difficulty coping with the lack of understanding from strangers and the stares and comments from curious children. In addition to these social effects, patients with facial paralysis can also experience difficulties with their speech, vision and ability to breathe through the nose, and problems eating and drinking. Eye irritation and blindness are additional concerns for patients who lose their ability to blink.
What Causes Facial Nerve Injury?
Trauma is one of the leading causes of damage to the facial nerve. Head injuries, penetrating injuries, or any swelling along nerve lines can damage the delicate network of nerves. In some cases, nerves are damaged unintentionally or sacrificed during surgery to remove a tumor. Facial nerves can also be damaged by infection and stroke. But oftentimes, there is no identifiable cause for the nerve damage. When this occurs, a person is said to suffer from Bell’s Palsy.
Patients with nerve damage due to Bell’s palsy can expect one of three possible outcomes, depending on the extent of their nerve damage.
- The majority of patients, about 85 percent, experience a complete recovery as the damaged nerve regrows over time.
- Others may experience an incomplete recovery, in terms of their nerves, but show very little cosmetic defects.
- A smaller percentage of patients experience profound, permanent damage that is obvious. It is this group, Most explained, who are candidates for surgical treatment.
Motor Nerves Can Recover
Facial nerve fibers extend across the entire face, with branches reaching into the five main motor branches. Because of the complex structure of the facial musculature, it can be difficult to recreate all of the tension vectors in the face if nerve damage occurs.
However, if the facial neurons are intact (in the brainstem), and the nerve is not severed, the nerve can regenerate. The likelihood of regeneration, and the degree to which the nerve recovers, depends on the severity of the injury and the distance the nerve has to regrow. If there is a chance for nerve recovery, conservative (non-surgical) measures are often used for facial nerve paralysis patients, Most explained.
“The degree of injury is very important,” Most explained. “If there’s a complete severing of the nerve, there is no chance of spontaneous recovery. Something else has to be done. If the nerve is intact, a patient can expect some level of recovery.” But the process is slow, he added. Nerves grow about one mm per day, and can take between 12 to 18 months to regrow.
“When patients are going through this process, it is a time of watchful waiting,” Most explained. “But it’s very frustrating for patients.” To help alleviate the symptoms of facial nerve damage while waiting for regrowth, physicians sometimes use drug therapies to decrease inflammation, anti-viral medications if the patient’s nerve damage is caused by Bell’s Palsy and surgical techniques to improve the chances for recovery.
Predictors for Recovery
There are sensitive diagnostic tests available to monitor nerve recovery. In the months after an injury and when the nerve is presumed intact (not severed), electromyographic (emg) tests can be performed to search for evidence of a recovering nerve before any visible signs of recovery are evident.
During an EMG, the physician places small electrodes on muscles in the face to measure their activity. “We do not want to see electrical silence when conducting this test,” Most said. “Depending on the response from the test, we can get an idea whether or not the nerve will regenerate.”
One of the most important considerations for facial paralysis patients is to protect the eye, Most stressed in his discussion. Blinking the eye provides vital moisture to the cornea. If a patient is unable to blink, the eye becomes exposed to air too long, which can lead to corneal injury and loss of vision. During the day, patients can use lubricating drops to give moisture to the eye. At night, patients must tape their eyelids shut to protect the eye while sleeping.
Protection of the eye can also be achieved by surgical techniques, Most explained. For problems with the upper eyelid, surgeons can place a tiny weight in the upper eyelid to pull the eye down. In this case, gravity pulls the eyelid down when the patient wants to close the eye (and voluntarily ‘releases’ the muscle that holds the eyelid up). Canthoplasty can be performed for patients with problems in their lower lid.”
Surgical rehabilitation around the eye can be done in patients with intact nerves where recovery is expected,” said Most. “Twelve to 18 months is a long time to wait.”
When Surgery is Necessary
For many patients, surgery is the only option to bring movement back to a paralyzed face.There are a number of procedures that can be used depending on the extent of the nerve damage.
- Primary surgical nerve repair: If the nerve ends can be easily re-attached, a repair of the nerve can be performed. This repair allows the severed nerve endings to regrow and ‘find’ their way back to the necessary targets. “If you can put both ends of nerve together, sew it back together, get axons to regrow, it’s the best option for patients,” Most said.
- Facial nerve grafting: If two segments of a nerve are severed, and unable to reconnect, surgeons can bridge the gap using a graft material taken from nerves in other parts of the body such as the neck, leg or arm. Patients may experience numbness in the area where the nerve was harvested, but this is usually well-tolerated.
- 12-7 nerve transfer: In some cases, the twelfth cranial nerve, which gives movement to the tongue, can be connected to the facial nerve and used to give function to the face. However, all or some of the movement of the tongue on one side is diminished.
Results of these techniques vary from patient to patient, but on average, there is an 85 percent chance of acceptable recovery with a primary surgical repair of a nerve, a 56 percent chance of recovery with cable nerve grafts and a 25 percent chance of recovery with 12-7 nerve transfers.
“The best outcome occurs in patients whose nerve is just sewn back up,” said Most. “But all of these grafting options are better than what you can expect from a muscle transfer.”
When there is no chance of spontaneous recovery and nerve transfer techniques have not worked, there is an option to replace muscle.
This surgical procedure restores/lifts the midportion of the face to a more normal position. Static facial slings lift the midfacial region to a more neutral position, but the face does not move. In the dynamic sling procedure, muscle tissue is ‘transferred’ from one position on the head to another, and is attached to the corner of mouth and nasolabial fold.
Dynamic muscle transfer:
The most commonly transferred muscle, the temporalis muscle, sits above the ear on the skull. Surgeons take a large portion of this muscle, turn it 180 degrees, and sew it into the facial tissue on the paralyzed side of the face. With this procedure, you are able to get some tension and facial movement, Most pointed out.
Free tissue transfer:
Muscle from one portion of the body is moved to the face, and connected to blood vessels and donor nerves. The advantage of this procedure is that there are more sources of muscle tissue, but it takes more time to reinnervate the muscle.
In every case of facial paralysis, Most goes through a series of steps to determine the best way to bring animation and nerve control back to a face. Is a primary repair possible? If not, can the nerve be grafted? If not, is the patient a candidate for a 12-7 transfer? Muscle transfer is considered as a last option.”
Reinnervation, the ability to supply the tissue with nerves, is always preferable,” said Most. “If reanimation of facial tissue is possible, we try that first.”
About the Speaker
Sam Most is the chief of the Division of Facial Plastic and Reconstructive Surgery at Stanford. He is also an associate professor in the Departments of Otolaryngology, Head and Neck Surgery and Surgery (Plastic) at Stanford. Well-regarded in the field of facial plastic reconstructive surgery, he has authored numerous articles, textbook chapters and reviews on the science and practice of this specialty. His clinical and basic research programs study facial nerve recovery after injury, and ways to improve the quality of life of patients with facial nerve injury.
Dr. Most received his medical degree from Stanford School of Medicine. He completed an internship in General Surgery at Yale University School of Medicine, and trained at the University of Washington’s Department of Otolaryngology-Head and Neck Surgery. Dr. Most completed his fellowship in Facial Plastic & Reconstructive Surgery at the University of Washington, where he went on to be come Chief of the Division. He also directed the Multidisciplinary Cosmetic Surgery Center there, prior to returning to Stanford.
For More Information:
Stanford Facial Nerve Clinic
Department of Otolaryngology
National Institute of Neurological Disorders and Stroke