Introduction

If you have Bell’s Palsy or another type of facial paralysis you are not alone. Each year nearly 40,000 Americans are diagnosed with Bell’s Palsy. Bell’s Palsy is a weakness or complete paralysis of the facial muscles, and is the most common cause of facial paralysis. The cause of Bell’s Palsy is not completely understood but may be caused by a virus. In addition, even more Americans develop facial paralysis as a result of trauma, infection, tumors and other causes. The worldwide incidence of facial nerve paralysis and facial nerve disorders is unknown, but is substantial. Throughout this section we will talk about facial paralysis and Bell’s Palsy and often use these terms almost interchangeably. Bell’s Palsy is just one type of facial paralysis, and is different from other types of facial nerve paralysis. We will point out these distinctions where they are important.

Facial paralysis is a weakness or lack of movement of the facial muscles. The facial muscles control facial movements and thus facial expression. Facial expression is such an important part of our daily interactions with others that paralysis of the facial muscles can have an enormous impact on our lives. Think about it. Facial paralysis impacts how we greet our spouse and kids in the morning; how we interact with colleagues and customers at work; how we socialize with friends and when meeting others. Facial paralysis can have a tremendous impact on self-esteem, even for the most successful and confident of us. Fortunately, in many patients the facial nerve weakness will improve on its own. For those whose facial nerve weakness does not improve spontaneously there are many treatment options.

We will give you a better understanding of Bell’s Palsy and other types of facial paralysis. We will review the different causes of facial paralysis and how the diagnosis is determined. We will discuss the rehabilitation, medical and surgical treatment options. With this knowledge we hope to reduce your anxiety and help you deal with the diagnosis and treatment of facial paralysis. The better informed you are, the better questions you can ask and the more you can be involved in your treatment.

This information is not intended to be a substitute for your doctors or other health care providers. We hope that this resource of information will be a positive source for you or someone you care about with facial paralysis. We wish you the best of luck and strength in dealing with facial paralysis.

Anatomy

The facial nerve is a nerve that travels from the brain, through a portion of the skull called the temporal bone, and ultimately to the muscles of the face that control facial expression. The nerves for hearing and balance exit the brain near the facial nerve and travel with the facial nerve through the skull. Frequently, conditions that affect the facial nerve may affect the nerve for hearing and balance, and vice versa. The facial nerve can be thought of as an electrical cord providing impulses to these facial muscles. Inside this cord there are thousands of fibers that are carrying impulses. When this "cord" exits the skull to travel to the facial muscles it branches to the various muscles. The facial nerve exits from the skull at a point just below your ear, and the branches of the facial nerve come through the cheek to different facial muscles. The branches of the nerve pass through the salivary gland in your cheek, the parotid gland. Occasionally, when an individual has his or her parotid gland removed for infection or tumor the facial nerve can be injured or weakened.

There are seventeen different muscles on each side of your face that control facial movement and expression. You have muscles that raise and lower the eyebrow, close the eye, wrinkle the nose, pucker, smile, frown, etc. Each of these muscles is controlled by a branch of the facial nerve telling it what to do and when to do it. Facial expression is a very intricate process with all these muscles working together.

You have a right and a left facial nerve that control the right and left sided facial muscles and for the most part work as mirror images. When we smile or frown or are surprised both sides of the face move in a similar way and both sides of the face look essentially the same; that is, the face is symmetric. There are times when we can control just one side of the face such as when we raise an inquisitive brow, or wink or even sneer. However, for the most part both sides of the face move together. When one side of the face does not work, then we notice this "asymmetry" during facial expression.

The facial nerve also has gives off branches to the lacrimal (tear) gland called the greater superficial petrosal nerve. This nerve helps to control tear production. Paralysis of the facial nerve can result in disturbances of tear production. The facial nerve also gives off a branch to the tongue called the chorda tympani nerve and a branch to the stapes which is one of the ear bones important for hearing. As a result, patients with facial paralysis may also complain of taste or hearing disturbances.

Anatomy of Facial Paralysis

In this chapter we will discuss what happens to the face in facial paralysis. One of the first things that you will notice with facial nerve paralysis is the "droopiness" of the face. Even when muscles are not actively contracting they have a certain amount of "tone". In other words, the muscles are contracting just a little to maintain the anatomic features of the face in their resting positions. When the muscles are paralyzed with no impulses from the facial nerve then the effects of gravity become apparent. The eyebrow will drop down lower than the opposite normal side. This often creates crowding and bunching of the skin of the upper eyelid. The lower eyelid often will fall away from eyeball resulting in ectropion. The tissues of the cheek fall. The corner of the mouth droops down resulting in the appearance of frowning in many patients. The degree of droop will also depend on other factors especially age. The older you are the less tone that your skin and other tissues have which results in worsening droop. Often young adults and children have such good tone to the skin and other tissues that there is very little noticeable droop to the face at rest.

However, when the speaking or expressing facial emotion the weakness becomes apparent in virtually everyone. It is this asymmetry during speech and facial expression that is the most stigmatizing aspect of facial paralysis for most patients. When smiling only the non-paralyzed side of the mouth moves up while the paralyzed side remains. In fact, the normal side of the face will often create further distortion or asymmetry due to lack of resistance of the paralyzed side. For example, the lips are often pulled toward the other side.

Speech can be different because of the difficulty of moving or puckering the lips in articulating certain sounds. Furthermore, some patients will complain of drooling because of the inability to pucker and completely close the lips. Saliva tends to pool on the paralyzed side of the mouth as a result of loss of tone. Simple things such as whistling and sucking on a straw become impossible. There are also muscles that help to keep the nostrils open such as when "flaring" the nostrils. This weakness can often cause difficulty breathing out of that side of the nose especially during vigorous activity.

One of the most important consequences of facial paralysis is the affect on the eye muscles, the orbicularis oculi muscles. These muscles are responsible for closing the eye. Blinking is important to lubricate and protect the eye, and everyday we perform this delicate maneuver thousands of times subconsciously. Facial paralysis results in the inability to close the eye, and consequently this causes the eye to dry out. The cornea is the covering of the eye and is very sensitive to drying. If the cornea is not kept lubricated it can result in irritation, pain and even blindness.

Causes of Facial Paralysis

There are many different causes of facial paralysis and it is important to try and determine the cause. The cause of a facial paralysis will determine what type of treatment may be appropriate as well as the prognosis for recovery. The most common cause of facial paralysis is Bell’s Palsy, but it is important not to assume that a facial paralysis is due to Bell’s Palsy without first considering other possibilities.

Bell’s Palsy

The cause of Bell’s Palsy is not known, and is therefore a diagnosis of exclusion. Bell’s Palsy was named Sir Charles Bell who first described the condition. Many people think that it is caused by a virus, and the viral infection results in inflammation and swelling of the facial nerve. There is some evidence that most cases of Bell’s Palsy may be caused by Herpes Simplex Type 1 Virus. Because the facial nerve is surround by bone as it passes through the skull there is little space for it to swell. The swelling of the nerve inside the bony canal causes the blood supply traveling with the nerve to be compromised. As a result the nerve is injured. Bell’s Palsy occurs suddenly resulting in partial or complete weakness of the face. Frequently, people complain of neck discomfort, ear pain and eye irritation. In addition, individuals often describe flu-like symptoms prior to the onset of the facial paralysis. Taste and hearing disturbances are not uncommon. Some patients will complain of the numbness of the face.

The incidence for men and women is about the same, but there is a higher incidence in diabetics and during pregnancy. Bell’s Palsy affects the right and left side of the face equally and occurs on both sides in less than 1% of cases. Interestingly, approximately 10% of people diagnosed with Bell’s Palsy have a family history of Bell’s Palsy. Approximately, 80 to 85% of patients will have a complete recovery within 4 to 6 weeks. The remaining patients that do not recover completely after 6 weeks may have some permanent weakness or sequelae. The longer the recovery takes the higher the likelihood of weakness or abnormal movement. All patients with Bell’s Palsy will have some recovery. If a patient does not recover at all then the diagnosis of Bell’s Palsy must be questioned. Bell’s Palsy may recur in less than 10% of patients.

Other Causes of Facial Paralysis

All facial palsies are not Bell’s Palsy. As previously mentioned it is very important to consider other causes. There are many different causes of facial paralysis and we will review some of the more common ones.

Trauma

Trauma is one of the more common causes of facial paralysis. Head trauma such as may occur in a car accident can result in skull fractures. If these skull fractures occur near or involve the course of the facial nerve, the nerve can be injured. Swelling of the nerve can result in further injury. In addition, because the facial nerve courses across the face, a deep cut on the face can potentially cut the facial nerve. Finally, certain surgical procedures can result in injury to the facial nerve. For example, we have talked earlier about the course of the facial nerve through the parotid gland. If the parotid gland has to be surgically removed because of tumor or infection the facial nerve can be injured. Operations on the nerve for hearing and balance can result in facial nerve injury. An acoustic neuroma is a tumor that occurs on the balance or hearing nerve. Because the facial nerve courses with these nerves it can be injured during surgery.

Tumors

Facial paralysis can result from tumors arising from the facial nerve itself or more commonly from tissues near the facial nerve. We have already mentioned acoustic neuromas, which are tumors of the balance nerve. Sometimes these tumors can get so large that the tumor compresses the facial nerve resulting in weakness. In addition, malignant tumors of the parotid gland for example can directly invade the facial nerve resulting in weakness. Although only representing 5-10% of causes of facial paralysis, it is important to make the correct diagnosis so that the tumor is properly treated. Unlike Bell’s Palsy, tumors usually result in facial paralysis that develops slowly over the course of several weeks or months.

Infection/Inflammation

There are a variety of bacterial or viral infections that can cause facial paralysis. Herpes Zoster Oticus (Ramsay-Hunt Syndrome) is basically a herpes zoster infection of the facial nerve. This is different from the Herpes Simplex Type 1 infection believed to possibly cause most cases of Bell’s Palsy, and the prognosis for recovery is worse Herpes Zoster Oticus. These patients may present with pain and blisters on the ear prior to or at the onset of the facial paralysis. Other infections including infections of the ear can cause facial paralysis. Remember that the facial nerve courses through the bone surrounding the ear. If the bone is deficient or the infection severe, the facial nerve may become inflamed and result in weakness. There are a variety of other unusual infections that have been implicated as a cause of facial paralysis. Lyme’s disease is infection caused by ticks that seems to have a predilection for facial paralysis. The common denominator is that the infection results in inflammation of the nerve and subsequent weakness.

Congenital

Congenital facial nerve paralysis refers to a facial paralysis present at birth. The most common congenital facial nerve paralysis is a result of birth trauma. It is believed to result from direct pressure on the facial nerve as the baby passes through the birth canal or pressure from a forceps delivery in some cases. Mobius Syndrome is the most common congenital syndrome associated with facial paralysis. These patients often will have weakness of the facial muscles on both sides of the face. In addition, they frequently will have a weakness of one the eye muscles (abducens muscle).

Melkerson-Rosenthal Syndrome

Melkerson-Rosenthal Syndrome is an unusual and rare cause of facial nerve paralysis. These patients will usually have recurrent facial swelling, recurrent facial nerve weakness and a fissured tongue, but not all three are required to make the diagnosis.

Other causes of facial nerve paralysis include stroke, vascular disorders and sarcoidosis.

Management of the Eye

Arguably one of the most important consequences of facial paralysis is the effect on the eye. Because the muscles responsible for closing the eye are controlled by the facial nerve, patients with facial nerve paralysis are unable to close the eye. Whenever you blink, the tear film is spread over the outer surface of the eye. This "squeegee" effect is very important in keeping the cornea lubricated. The cornea is the transparent tissue covering the outer surface of the eye. Everyday we blink thousands of times and this helps to keep the cornea from drying out. In addition, the facial nerve is responsible for tear production, so not only is the eye not closing with facial nerve paralysis, but also insufficient tears are produced. If the eye is not properly lubricated and protected, then cornea exposure can result and (exposure keratitis) potentially vision impairment and even blindness.

Your doctors will examine your eye to check for signs of irritation including redness of the sclera (white part of the eye). He or she may also put fluorescein dye in your eye and examine it with a blue light. This helps to identify injury to the cornea not apparent to the naked eye. Normally, when we close our eyelids the eyeball turns up. This is called a Bell’s phenomenon and is important because when the eye turns up it is at least partially covered by the eyelid. Those patients who do not have a Bell’s phenomenon may be at even greater risk for eye injury. Your doctor may also check your corneal sensation by gently touching your eye with a wisp of cotton. Normally, if you cannot feel it, you may not be aware of corneal injury.

The first step in taking care of your eyes is to keep it well lubricated. This means frequent use of artificial tears, up to every hour or more. At night eye lubricants can be used to keep the eye moist while sleeping. Humidity chambers and other types of eye patches can be used to keep the eye covered at night. The eye can be taped shut at night, but you must be careful so that the tape does not scratch your eye. Goggles or other type of protective eye wear should be used outside to protect the eye from the wind and foreign bodies. The wind can quickly dry the eye out. You may even notice this in long hallways with a draft. Any soreness, increased redness or change in vision should be discussed with your doctor. Frequently, you may be examined by an eye doctor.

For those patients in whom facial nerve recovery does not occur in a timely manner, and in whom lubrication is not enough, there are other options to help closed the eye.

Gold Weights

A very small weight made out of gold can be placed under the skin of the upper eyelid to help close the eye. The eye normally has a muscle that closed the eye (controlled by the facial nerve). The logic for using a weight in the upper eyelid is that when you attempt to close the eye, the muscle that normally lifts the upper eyelid relaxes so that the weight can help close the eye by gravity. Gold is an ideal material because it is heavy, inert, and does not show well through the skin.

The procedure is fairly simple and can be performed under local anesthesia. Several test weights are taped to the upper lid to estimate the appropriate size gold weight that will satisfactorily close the eye, but not cause drooping of the eyelid at rest. An incision is made in the crease of the upper eyelid and a pocket created for the gold weight. The gold weight is sewn to the underlying tarsus. The tarsus is a supporting structure of the eyelid. The procedure is reversible, and the weight can be removed if facial nerve function returns. There are other surgical procedures that can be performed on the upper eyelid to help closure such as springs and muscle flaps, but the gold weight is the most common. Occasionally, the outer half of the eyelid is sewn together to help protect the cornea. This is referred to as a lateral tarsorrhaphy and is usually reserved for situations when a gold weight is not working satisfactorily or the condition of the eye is severe.

Ectropion is a condition of the lower eyelid in which the eyelid actually falls away from the eyeball. This is often referred to as paralytic ectropion and is due to the lack of tone of the eyelid and inability to resist the effects of gravity. It is more common in older patients with facial paralysis who already have poor tone of the skin. There are a variety of procedures that can be performed to tighten up the lower eyelid. Another common problem related to the eye is droopiness of the eyebrow, called brow ptosis. Brow ptosis results in the paralyzed eyebrow being lower than the unparalyzed side and this can create asymmetry. In addition, droopiness of the eyebrow can cause crowding and excess skin of the upper eyelid. Brow ptosis can be corrected by a surgical brow lift or medical jargon a browpexy. There are several different techniques to accomplish this goal including removing excess skin and hiding the incision in the eyebrow itself, a direct brow lift. Other techniques include hiding the incision in a middle forehead skin crease, a mid-forehead lift or placing the incision on the top of the scalp, a coronal browlift. Recently, endoscopic browlifts have become popular where only small incisions are made behind the hair line and telescopes are used to facilitate the browlift. If there is still a redundancy of skin after the browlift, a blepharoplasty can be performed to remove the excess skin. Caution must be exercised so that too much skin is not removed making closure of the eye more difficult.

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