What is Facial Nerve Trauma (Injury to the Face Nerves in the Skull)?

Facial nerve palsy, or paralysis of the face, is a common issue seen in general clinics, emergency rooms, ear, nose, and throat clinics, and brain specialist offices. Injury causes between 6 to 27% of all cases, depending on whether we include injuries from surgery related to tumors (like when removing a large part of the salivary gland for cancer treatment) as “trauma”. The most usual reasons for face paralysis due to injury are tumor removal, fractures of the bone near the ear, and any penetrating injuries to the facial nerve, even those accidentally caused during treatment.

Facial paralysis can greatly impact a person’s quality of life, as it affects many daily activities. This is because the facial nerve is involved in a lot of our everyday functions.

Not only is there an emotional toll due to a changed facial expression, but facial nerve palsy can also lead to eye, ear, nose, tasting, and speaking related complications. For instance, eye-related issues due to decreased tear production, outward turning of the eyelid, and overflow of tears can lead to damage of the cornea, which can eventually result in blindness if it’s not caught and treated early. Ear-related complications can lead to heightened sensitivity to sound and numbness in parts of the ear canal. Weak muscle support to the nostrils can result in difficult breathing through the nose. Problems with mouth muscle control can lead to changed speech and difficulty keeping the mouth shut. Damage to a specific branch of the facial nerve can even hinder the sense of taste.

What Causes Facial Nerve Trauma (Injury to the Face Nerves in the Skull)?

Damage to the facial nerve, which can cause facial paralysis, can happen under various circumstances. Some of these situations include:

* Fracture to the base of the skull, especially the temporal bone (located at the sides and base of the skull)
* Trauma to the facial nerve outside of the skull from things like knife or gunshot wounds
* Trauma during childbirth, mostly happening with the use of forceps during delivery
* Medical-based trauma, generally during the removal of a tumor or during surgery on the face or the mastoid (bony part of the skull behind the ear)
* Damage due to pressure changes, often experienced while scuba diving or during airplane travel
* A lightning strike.

In all the scenarios above, the damage causes facial paralysis, which is the loss of voluntary muscle movement in the face. This could affect the person’s ability to move their facial muscles, like when smiling or blinking.

Risk Factors and Frequency for Facial Nerve Trauma (Injury to the Face Nerves in the Skull)

Figuring out how often facial nerve damage occurs in general can be tough. But if we look at it as a part of overall cases of facial paralysis, it becomes a bit easier. In 2014, a study found that out of nearly 2,000 patients with facial paralysis, 5.6% of these cases were due to accidental injury. But when injuries caused by medical treatment were included, the number increased to 27%.

Another study in 2009 looked at the medical records of 54 patients with facial paralysis and found that 24% of them were due to injury. But a 1996 study found only 8% of facial paralysis cases to be caused by injury. More recently, a 2021 study found that 35% of facial paralysis were due to injury.

Some common causes of facial nerve damage are surgeries to remove acoustic neuroma and parotid tumors, jaw and middle ear surgeries, skull fracture around the ear, and injuries during birth. The chances of these happening can vary widely depending on the setting and the specific patient population.

In major trauma centers, fractures of the bone surrounding the ear (temporal bone) can be a common reason for facial paralysis; it happens in 7 to 10% of all these kinds of fractures. This bone is pyramid-shaped and very dense, meaning a lot of force is needed to break it. As a result, 31% of these fractures happen due to car accidents. The next most common reasons are assault and falls.

It’s important to note that approximately 90% of fractures in this area are associated with brain injuries, and 10% are linked with neck injuries. Therefore, it’s crucial to check patients with these types of fractures for other injuries as well.

Signs and Symptoms of Facial Nerve Trauma (Injury to the Face Nerves in the Skull)

When a patient has sudden facial paralysis because of an accident, tracking how quickly the paralysis happens and how severe it is, are the two most crucial pieces of information. If the paralysis is instant and total, there’s a good chance the facial nerve has been cut. On the other hand, if the paralysis appears gradually or is incomplete, it’s likely that the nerve is only partially damaged. If a cut nerve is suspected, further checks and treatment for the injury should be carried out. Patients with a partially damaged nerve can typically be observed, expecting a good recovery. In some instances, facial paralysis due to a head injury can take a while to reach its worst due to swelling, which can develop slowly within the facial nerve canal. Patients with complete paralysis from such types of injuries may need treatment to relieve the nerve, so close follow-ups are essential.

In some cases, it may not be very straightforward to determine the timeline and severity of the paralysis. An example could be during long surgeries where a nerve gets accidentally injured early and the paralysis isn’t noticed until the patient wakes up from anesthesia. Or a patient with severe injuries, including head injuries, that is unconscious, sedated, and can’t communicate or provide a history of paralysis onset. In such cases, it’s up to medical professionals to try and gather as much information as possible, perhaps from relatives, friends, paramedics, or bystanders, and monitor the shape and function of the facial nerve as systematically and thoroughly as possible.

There are different ways to categorize impaired facial nerve function. The most common is the House and Brackmann scale, described as follows:

  • Grade I: Normal function
  • Grade II: Mild dysfunction, slight unevenness with movement but can fully close eyes with gentle effort
  • Grade III: Moderate dysfunction, even at rest, moderate unevenness with movement, can fully close eyes with full effort
  • Grade IV: Moderate dysfunction, even at rest, moderate unevenness with movement, can’t fully close eyes despite full effort
  • Grade V: Severe dysfunction, very uneven at rest, significant unevenness with movement, can’t fully close eyes despite full effort
  • Grade VI: No movement at all, very uneven at rest

Other classification systems can provide a more detailed description of facial paralysis, but for record-keeping, a systematic description of the functional status of each major facial nerve branch could be simpler and more accurate.

It’s also crucial to understand the facial nerve’s functions that aren’t related to emotion, evaluated by asking the patient about hearing, tasting, breathing through the nose, dry or painful eyes, and eye watering. In the case of patients who have had surgery or injury at the base of the skull, a simple test with a cotton wisp can help check sensation in the cornea. Patients with conditions like acoustic neuroma resections might not feel the progress of damage to the cornea due to heightened sensitivity, increasing the risk of long-term eye problems. These patients might need early placement of an eyelid weight, as are patients who can’t protect their corneas due to poor eye closure reflex.

It’s equally important to assess the patient’s emotional status, as the psychological impact on patients, particularly young females, can be substantially high and might require mental health support. Patients with significant injuries, especially fractures in the temporal bone, require checks for other injuries like fractures in the spinal cord, cerebrospinal fluid leaks, and other intracranial issues, as they often come with such types of injuries in about 90% of cases.

Testing for Facial Nerve Trauma (Injury to the Face Nerves in the Skull)

If you’re experiencing facial paralysis due to an accident, your doctor may conduct a series of tests to identify and evaluate damage to your facial nerve. The first of these tests is often a non-contrast computed tomography (CT) scan. This scan is used to assess for injuries on the bone around the ear known as the temporal bone. The doctor may also use electrodiagnostic studies to determine the extent of the nerve-related damage.

Other tests might also be done to check for related injuries. For example, they may test the fluid coming from your nose or ear to determine whether it is cerebrospinal fluid, which shields the brain and spinal cord. This is done to exclude any leaks. They may take an X-ray of the neck to rule out fractures in the cervical spine. They also may check for hearing loss using an audiogram, a test that evaluates your hearing abilities.

One form of electrodiagnostic testing is Electroneuronography (ENoG). In this test, the doctor applies a mild electrical signal to the facial nerve at the point where it leaves the bone around your ear. Electrodes then measure the response from your facial muscles. The responses are compared between the injured and uninjured sides to determine the severity of the damage. This test is usually done 72 hours or more after the injury. It is especially useful if complete facial paralysis has occurred. This helps the doctor assess if the damage is as serious as it appears on physical examination.

If there is a loss of more than 90% of the nerve’s activity on the injured side compared to the healthy side, the damage is considered severe. The patient might then be recommended for a facial nerve decompression surgery if a temporal bone fracture was present. This is a surgical procedure to relieve pressure on the nerve to improve nerve function.

Voluntary electromyography (EMG) is another form of electrodiagnostic testing used later in the course of facial paralysis. It is used to check the muscle’s health and establish whether they can receive nerve signals. This is done by testing for the presence of different wave patterns such as fibrillation, positive sharp waves, and polyphasic potentials in the muscles. Flat lines and absence of electrical activity on EMG could mean the muscle is no longer viable due to prolonged lack of nerve supply, muscle shrinkage and scarring.

In such cases, facial nerve decompression or repair may not be necessary if voluntary motor unit potentials (nerve signals controlling voluntary muscle activity) are still present even after a significant loss of nerve activity as shown in the ENoG test.

Treatment Options for Facial Nerve Trauma (Injury to the Face Nerves in the Skull)

Treating traumatic facial paralysis is aimed at preserving or restoring as much facial mimic function as possible. This can be achieved in numerous ways depending on the severity of the injury and the duration between the injury and the patient seeking help.

In the acute phase of injury, which is less than 12 months since the injury, doctors typically recommend corticosteroids, a type of anti-inflammatory drug, to bring down the swelling and inflammation of the facial nerve. Doctors do have to take into consideration certain factors, such as if a patient has diabetes or ulcers, since steroids can have potential side effects. Calcium channel blockers, such as nimodipine, may also be used to improve outcomes after facial nerve trauma by reducing cell death and improving axonal sprouting, the growth of nerve fibres.

It’s imperative to closely monitor the health of the patient’s cornea, the outermost layer of the eye. This is particularly important for patients who have nerve injuries in the brain that could also impact the sensation in the cornea. Patients who cannot feel corneal injuries are at high risk of developing complications. Standard treatment for lagophthalmos—when one cannot close their eyes completely—should include artificial tears during the day, eyelid exercises, and night-time lubricant, sometimes alongside eyelid taping. Considering it necessary, doctors might recommend additional procedures such as fitting for a scleral contact lens or placement of an upper eyelid weight.

In cases where it is known or suspected that the facial nerve has been cut, doctors will attempt to locate the site of injury and repair the nerve. This is ideally performed within the first 72 hours after injury to minimize nerve cell death, making it easier to find the nerve in the wound bed. Appropriate local anesthetics are used, but ones that last longer than 2 hours are avoided as they can interfere with the use of a nerve stimulator, which is used for locating the nerve.

In certain situations, the surgeon may find the facial nerve surrounded by scar tissue. Removing the scar tissue can help reduce inflammation and improve function. If the scar tissue extends into the nerve, the nerve should be cut back to healthy tissue. When the gap between nerve ends is greater than 6 mm, an interposition graft is used. This is preferable to stretching the nerve ends, which can reduce blood supply and hinder recovery. A common source of graft material is the greater auricular nerve, which matches well with the facial nerve in size.

Diagnosing facial palsy caused by an injury is generally straightforward, but sometimes other conditions can complicate the picture. For instance, a person might display facial paralysis due to viral conditions like Bell’s palsy, zoster sine herpete/Ramsay Hunt syndrome, or even a facial paralysis related to COVID-19. These can all develop alongside a physical injury, particularly under stressful conditions. In certain cases, a stroke may also accompany severe injuries, causing facial paralysis even without an actual nerve injury.

Another tricky situation is when facial nerve damage happens due to pressure changes, such as from diving or high-altitude travel. This can be especially hard to pinpoint if it coincides with hearing loss and if there isn’t obvious evidence of the activities that might have caused it.

When a newborn baby has facial weakness, distinguishing between damage from birth trauma and a birth defect requires careful evaluation. Birth trauma typically results in weakness on one side of the face because of stress to the main facial nerve or injury to the temporal bone. On the other hand, congenital facial paralysis usually presents as a weakness in a specific area (like unilateral lower lip palsy) or weakness on both sides of the face, sometimes with other nerve-related issues, as seen in Möbius syndrome. Making this distinction can take some time, as paralysis from birth trauma often improves somewhat over time and could lead to synkinesis, whereas congenital palsy remains stable.

What to expect with Facial Nerve Trauma (Injury to the Face Nerves in the Skull)

The outlook for patients who experience facial paralysis because of injury primarily depends on how severe the injury is, and for serious injuries, how successful the repair is. Since there are many different ways in which a person could suffer from facial paralysis, it’s not easy to predict exactly how much function a person will recover. However, research suggests that most people recover significantly after timely nerve repair. For instance, a study conducted in 2013 reported that most patients regain at least 90% of their ability to smile symmetrically, 60% can close their eyes without needing special devices, and 40% regain the ability to raise their eyebrow.

In general, patients with mild to moderate injuries have a good chance of almost complete recovery. This means that their paralysis is either not total (only some parts of the face are affected) or starts some time after the injury. Patients with severe injuries that result in immediate, total paralysis of one half of the face have a less certain recovery. Still, if a test (ENoG) is conducted and shows less than 90% loss of nerve signals, there’s a chance for total recovery, albeit less likely compared to those with partial or delayed paralysis. For patients needing repair of the main part of the facial nerve, the best they can expect is a modest level of recovery with some involuntary movements.

Outcomes also depend on whether the damage is to the main facial nerve or a branch. Those who experience injuries to the main facial nerve and do not seek repair are likely to suffer from long-term paralysis. However, if the injury is to a branch of the facial nerve, the outlook is more positive because the effect on facial function is less significant. For very specific injuries to the area medial or towards the nose side of the corner of the eye, the chances of good recovery are high because there is a dense network of small nerve fibers in that region.

Deciding whether or not to have surgery should be done with patience as recovery from nerve injury is slow due to nerve growth rate. It grows approximately 1 mm a day and often, the results of a nerve repair or even natural recovery are not evident for 6 to 12 months.

Possible Complications When Diagnosed with Facial Nerve Trauma (Injury to the Face Nerves in the Skull)

When facial paralysis occurs due to an accident, it can lead to a number of serious complications. This could include a risk of blindness due to weakened eye protection, constant tearing or excessive dryness of the eyes, difficulty breathing due to a blocked nose, increased sensitivity to sound, drooling, and even social issues like isolation or low self-esteem.
If facial paralysis remains untreated for a long time, it might lead to involuntary face movements, uncoordinated facial expressions, and facial pain. After the surgical repair of the facial nerve, patients may witness other challenges. These can involve harm to healthy branches of the facial nerve, failure to regain function after surgery, and issues at the site from where the replacement nerve or tissue was taken (like loss of sensation, muscle atrophy due to absence of nerve stimulation, or failure of the inserted tissue).

Common complications:

  • Weakened eye protection leading to potential blindness
  • Constant tearing or dry eyes
  • Blocked nose leading to difficulty in breathing
  • Increased sensitivity to sound
  • Drooling
  • Social issues: isolation or low self-esteem
  • Involuntary facial movements
  • Uncoordinated facial expressions
  • Facial pain
  • Injury to healthy branches of the facial nerve
  • Failure to regain function after surgery
  • Problems at the site from where the nerve or tissue for repair was taken

Preventing Facial Nerve Trauma (Injury to the Face Nerves in the Skull)

One of the easiest ways to reduce the chance of traumatic facial paralysis is by regularly wearing helmets when doing activities that could result in a strong impact to the head. This includes driving motorcycles and all-terrain vehicles, handling heavy machinery, and playing contact sports. Wearing a helmet has been proven to decrease the chances of skull fractures.

However, it can be hard to predict and prevent other causes of injury. Iatrogenic injury, caused by medical treatment or procedures, is another key area for efforts on patient safety. A common cause of iatrogenic facial nerve injury is in temporomandibular joint replacement surgery, a procedure for the joint that connects your jaw and skull. It is not usually necessary to pinpoint the exact location of the facial nerve during this surgery. Instead, doctors might use a facial nerve monitor, or start identifying facial nerve branches during the operation, to lower the chances of nerve injury.

Facial nerve monitoring has been a standard part of otological (ear) surgery for a long time, because it helps to avoid injuring certain parts of the facial nerve located around the ear. In cancer-related head and neck surgery, particularly for the parotid gland (a type of salivary gland), it’s not entirely clear if nerve monitoring definitely reduces nerve injury. However, there’s some evidence that nerve monitoring can decrease the chance of facial paralysis after surgery and potentially improve long-term outcomes for the facial nerves.

In cosmetic surgery, facial nerve monitoring isn’t commonly used as surgeons prefer to avoid the facial nerve entirely, using key points on the face to avoid it, instead of using a nerve monitor due to its cost.

Knowing where the major branches of the facial nerve are in relation to the surface of the face can greatly affect the outcome of a face lift surgery. In particular, knowledge about the location of the frontal and marginal mandibular branches, which are often injured during a face lift, can make a significant difference.

In most patients, the marginal mandibular branch of the facial nerve, which runs closely along with the facial vein and is just above the facial artery, is located above the lower edge of the jaw throughout its course. But, for about 20% of the population, it’s below the lower edge of the jaw towards the back of the jaw.

The midfacial and cervical branches are injured less often, although injuries can still cause a weak smile. Injuries to the cervical branch, which generally runs about halfway under the line between the bottom of the chin and the tip of the mastoid bone just behind and under the ear, can be mistakenly thought to be injuries to the marginal mandibular branch, as both these branches help control the muscles that pull down the lower lip. The main branch that controls the zygomaticus major muscle, which controls smiling, is located halfway along a line between the corner of the mouth and the root of the ear helix, a location also known as Zuker’s point.

Frequently asked questions

Facial nerve trauma refers to injuries or damage to the facial nerve, which can cause weakness in the muscles of the face. It is a common reason for people to visit various clinics, including primary care, emergency, ear, nose, throat, and neurology clinics. The most frequently identified causes of facial paralysis following trauma are tumor removal, fractures of the temporal bone, and injuries to the facial nerve caused by medical procedures.

Around 5.6% - 35% of facial paralysis cases are from trauma, depending on different studies.

Signs and symptoms of Facial Nerve Trauma (Injury to the Face Nerves in the Skull) include: - Facial paralysis after a traumatic injury - Onset and severity of paralysis - Immediate and complete paralysis suggests nerve transection - Delayed and incomplete paralysis suggests the nerve is at least partially intact - Monitoring the patient's condition and progress over time - Surgical intervention might be required to repair a cut facial nerve - Swelling within the facial nerve can develop slowly over days or weeks - Total paralysis may require surgery to alleviate pressure on the facial nerve - Evaluating the functionality of each facial nerve branch thoroughly - Assessing other non-emotional roles of the facial nerve, such as hearing, taste, nasal breathing, and eye functions - Assessing the sensation in the cornea (the clear exterior part of the eye) if the base of the skull is impacted - Emotional wellbeing, especially in young women, should be considered as facial paralysis can have a profound psychological impact - Looking for other injuries, such as fractures in the spine, brain injuries, or cerebrospinal fluid leaks, in cases of trauma involving multiple injuries, especially temporal bone fractures.

Damage to the facial nerve, leading to facial paralysis, can occur in many different situations such as serious head injuries, piercing injuries to the face, birth injuries, medical procedures, sudden changes in pressure, and being struck by lightning.

The doctor needs to rule out the following conditions when diagnosing Facial Nerve Trauma (Injury to the Face Nerves in the Skull): 1. Trauma-related injuries, such as fractures of the temporal bone and injuries to the facial nerve caused by medical procedures. 2. Other injuries or health issues that may overlap with the symptoms, including viral conditions like Bell's palsy, Ramsay Hunt syndrome, or facial paralysis due to COVID-19. 3. Stroke, which can cause facial weakness even without actual injury to the facial nerve. 4. Facial nerve barotrauma, which can occur from diving or traveling at high altitudes and may coincide with hearing loss. 5. Birth trauma, which can cause facial weakness on one side of the face due to stretching of the main facial nerve or head bone injury. 6. Congenital facial paralysis, which may present as weakness on one side of the face or weakness on both sides of the face, accompanied by other nerve disorders like Möbius syndrome.

The types of tests that may be needed for Facial Nerve Trauma (Injury to the Face Nerves in the Skull) include: - Non-contrast computed tomography (CT) scan to check for bone fractures in the ear - Electrical tests such as electroneuronography (ENoG) to assess the severity of facial nerve damage - Tests to check for other injuries related to facial paralysis, such as tests to check for fluid leakage around the brain or spinal cord, X-rays to check for neck bone fractures, and hearing tests to assess hearing loss - Voluntary electromyography (EMG) to determine if the muscles are still receiving signals from the nerves and if they are able to respond.

Facial nerve trauma, or injury to the face nerves in the skull, can be treated through various methods depending on the severity of the injury. Treatment options may include medication, physical therapy, and in some cases, surgery. Medications such as corticosteroids may be prescribed to reduce inflammation and promote nerve healing. Physical therapy can help improve muscle strength and coordination in the face. In more severe cases, surgery may be necessary to repair or reconstruct damaged nerves. It is important to consult with a healthcare professional for an accurate diagnosis and appropriate treatment plan.

The side effects when treating Facial Nerve Trauma (Injury to the Face Nerves in the Skull) can include: - Eye problems such as dryness, tearing, and potential blindness - Nasal blockage - Increased sensitivity to sound - Difficulty controlling saliva - Social isolation or decreased self-esteem - Involuntary movements, lack of coordination, and facial pain There are also potential risks of facial nerve repair, which can include: - Damage to unaffected parts of the facial nerve - Lack of improvement after the procedure - Problems at the site where the nerve or tissue was taken for repair, such as sensory loss, muscle shrinkage, or failure of the transplanted flap.

The prognosis for facial nerve trauma depends on the severity of the injury and the success of the repair. Patients with mild or moderate injuries have a good chance of recovering normal or nearly normal function. Patients with incomplete paralysis from injuries to the temporal bone in the skull have a 100% chance of recovering completely. However, patients with severe injuries that cause immediate full paralysis may have a lower chance of full recovery, especially if there is more than 90% loss of nerve activity.

You should see a doctor specializing in facial nerve trauma, such as a neurologist, otolaryngologist (ear, nose, and throat specialist), or a facial plastic surgeon.

Join our newsletter

Stay up to date with the latest news and promotions!

"*" indicates required fields

This field is for validation purposes and should be left unchanged.

We care about your data in our privacy policy.