Temporal Fracture

What is Temporal Fracture?

The temporal bone is a large bone that is located at the lower side of the skull. To break it, a heavy impact is required, such as 1,875 pounds or 850 kg. This level of trauma can damage the associated structures of the bone, leading to serious health concerns or even death.

The structure of the temporal bone is quite complex. The bone consists of four regions and many holes and channels. It’s one of a pair of bones at the base of the skull, connecting to the back with the occipital bone, on top with the parietal bones, towards the front and center with the sphenoid bone, and towards the front and side with the cheekbone arches.

The squamous part of the temporal bone forms the side of the cranial vault, the upper part of the skull. From this part, the zygomatic process, making up the rear of the cheekbone arch, projects outward. The mastoid part contains the mastoid air cells, while the tympanic part encloses the middle ear gap and tiny bones.

The petrous pyramid is a dense segment of the temporal bone. This pyramid is wider at the skull’s side and becomes narrower as it goes towards the sella turcica. It contains the inner ear structures and the internal auditory canal. Moreover, the styloid process extends from the petrous part of the temporal bone. Apart from the hearing structures, the facial and chorda tympani nerves also pass through these sections of the temporal bone.

The foramen lacerum carries certain nerves and a few small arterial branches. The carotid canal contains the internal carotid artery, running parallel to the Eustachian tube on its way to the circle of Willis. The internal auditory canal accommodates the nerves associated with the cochlea (auditory nerve) and the vestibular nerves (balance nerves).

The jugular foramen, located within the suture line between the temporal and occipital bones, carries structures like the internal jugular vein, posterior meningeal artery, and certain nerves. The stylomastoid foramen, another hole in the skull, carries the facial nerve to the parotid gland, a salivary gland.

What Causes Temporal Fracture?

Temporal bone fractures, or breaks in the bone near the side of the skull, usually happen because of a strong force hitting the head. This can happen front-to-back, like in car crashes, or side-to-side, which may occur during a physical fight. When the force comes from front to back, it’s more likely to cause a specific kind of fracture in the inner part of the skull and may harm the inner ear and facial nerves. Side-to-side forces, on the other hand, might cause fractures that run parallel to the inner part of the skull, which usually leaves the part of the ear within the skull undamaged.

Over half of these fractures in adults are caused by car crashes. Other common causes include falls, accidents, and assaults. In children, however, falls cause twice as many of these fractures as car crashes do.

Risk Factors and Frequency for Temporal Fracture

Temporal bone fractures, or breaks in a particular bone of the skull, mostly happen on one side, but may affect both sides due to car accidents or other serious incidents. These fractures are just as likely to happen on the left as on the right side of the head. They are more common in males, who are three times more likely to experience this than females. Temporal bone fractures can account for 30-70% of head injuries from blunt force trauma.

• While kids can suffer from these fractures due to falls, most cases occur in people aged between 11 and 40.
• About 70% of people with temporal bone fractures experience hearing loss. Most of these (66%) are conductive losses, where sound isn’t sent properly to the inner ear. Some (5%) are sensorineural losses, related to damage in the inner ear.
• Facial paralysis happens in 7-12% of cases, especially if the area near the ear inside the skull is involved in the fracture.

These fractures usually occur when the head is subjected to strong force. Car accidents are responsible for about half of these fractures in the general population. Other major causes include falls, assaults, and various accidents.

Signs and Symptoms of Temporal Fracture

In cases of significant head trauma, it’s necessary to consider the possibility of skull fractures. A fracture to the temporal bone, which requires considerable force, might cause changes in mental awareness or an abnormal score on the Glasgow Coma Scale, a test used to assess consciousness after a brain injury. In such scenarios, the patient must be immediately evaluated for life-threatening conditions like issues with airway, breathing, circulation, and conscious level (ABCDE), and resuscitation should be initiated if required. Doctors also need to check for other injuries such as bleeding or fractures.

Once immediate concerns have been addressed, the medical team needs to understand how the injury occurred. This information can come from either the patient, eyewitnesses, or first-responders. It’s crucial to record any changes in the patient’s mental status along with symptoms like a headache, nausea, vomiting, dizziness, ringing in the ears, hearing loss, or confusion.

The physical examination includes checking vital signs and any changes in the patient’s respiratory pattern. Any lacerations or bruises on the head and body should be noted, along with signs of bleeding or clear fluid from the ears or nose, hearing loss, or a bruise behind the ear (Battle’s sign).

Along with general observations, the following tests are used when diagnosing a fracture to the temporal bone:

• Weber test: A tuning fork is placed on the patient’s nose or teeth to test for hearing loss.
• Rinne test: A tuning fork is used near the ear and behind it to compare air and bone conduction of sound.
• Weber and Rinne tests combined: These are used to determine the location of the injury and type of hearing loss.
• Dix-Hallpike test: This checks for vertigo, which might occur after head trauma.
• Head thrust test: This examines the patient’s eye coordination as their head is moved from side to side.
• Head shake test: The patient’s head is gently shaken to check for signs of an imbalance in the inner ear.

In unconscious patients, an examination may reveal signs of a skull fracture or bleeding in the ear. Fluid leaking from the ear or nose may suggest a serious head injury and can be tested to see if it is cerebrospinal fluid (CSF), indicating a skull base fracture. Fractures to the temporal bone can damage the facial nerve, so any signs of facial paralysis will need to be assessed for severity and onset. The doctor will also evaluate any changes in facial movements using the House-Brackmann scale, a common system for grading facial nerve function. However, complete facial nerve damage may result in a closed eye due to gravity, which can be confused as preserved facial nerve function.

Testing for Temporal Fracture

Patients with injuries from trauma may need surgery straight away or a blood transfusion. Plus, they might need blood tests as soon as they’re admitted to hospital. These could be a full blood count, a coagulation profile, a test to find out their blood type, and a complete metabolic panel. If someone is unconscious, their doctor might use a fingerstick glucose or random blood sugar test to check for and treat low blood sugar. A urine test might also be needed because injuries to the bladder or kidney could lead to blood in the urine. 

Taking images is really important for doctors who are caring for patients who’ve recently had a traumatic injury. They will need to get X-ray images to see if there are any fractures in the spine or pelvis. These images allow doctors to examine parts of the body thoroughly. X-ray images might also show that other parts of the body are fractured.

The computed tomography (CT) scanner can identify temporal bone fractures (these are fractures in the bone near the ear), which can be seen more easily than during a physical exam. Temporal bone fractures are often linked to injuries inside the skull. These fractures usually show up on a regular head CT scan when a person with a recent traumatic injury is first examined. When this kind of fracture is identified, a more detailed CT scan is needed.

In addition to fractures in the skull, a CT scan can also identify different types of bleeding in and around the brain. If the fracture is in an area where major blood vessels are present, a CT angiography would be required. If there is a leak of cerebrospinal fluid (this is the fluid that surrounds the brain and spinal cord), this can be diagnosed with a β-2 transferrin test, and the location of the leak can be found through a CT cisternogram.

Patients who are stable might need a magnetic resonance imaging (MRI) scan for problems inside the skull, like cranial nerve palsy, that can’t be seen on a CT scan. For instance, an MRI scan can show whether there is fluid or intracranial herniation (when part of the brain is pushed out of place) in a part of the skull called the mastoid area.

Imaging can also help doctors put fractures of the temporal bone into categories. One system that’s often used looks specifically at whether there is injury to the otic capsule (a part of the inner ear). Depending on the severity of the injury to the otic capsule, this can lead to different symptoms. For example, it could cause hearing loss, facial nerve paralysis, or a cerebrospinal fluid leak.

Before this system was used, fractures were categorised based on whether they were perpendicular or parallel to the petrous ridge (a part of the temporal bone near the ear). This older system didn’t account for oblique fractures, which are at an angle and weren’t classifiable as either perpendicular or parallel.

Stable patients with temporal bone fractures will need further tests. These might include hearing tests which can also assess facial nerve function and balance tests for patients with dizziness. If the facial paralysis is severe, electrodiagnostic tests will be done to see how bad the nerve injury is and whether surgery would be helpful.

Traditionally, minimal nerve excitability and maximal stimulation tests were used to check facial nerve function. But now, the gold standard is electroneuronography (ENoG), which measures muscle response to electrical stimuli. This test is useful for patients with complete facial palsy lasting at least 3 days.

You have to wait for three days after the injury to do ENoG because it doesn’t assess the geniculate region (this is the part of the facial nerve most commonly affected by temporal bone fractures) directly. Instead, it looks at the effects of Wallerian degeneration, which is a process that happens after nerve injury. Wallerian degeneration could affect the geniculate region, so it’s important to give it some time to manifest.

Wallerian degeneration after a temporal bone fracture might happen more slowly than in Bell’s palsy. You might need to do ENoG tests repetitively for up to two months until either recovery happens or the patient meets the criteria for surgery. If the amplitude (strength of the electric signal) of the compound muscle action potential (this is a measure of nerve function) on the affected side has lost at least 90%, it’s an indication for surgery.

Electromyography (EMG) is useful for monitoring recovery after a temporal bone fracture. But even if a patient is showing signs of recovery, or the ENoG results are improving, EMG results might still be abnormal.

Treatment Options for Temporal Fracture

If a patient is unconscious and not breathing with no pulse, immediate emergency measures must be taken to save their life. Once they are stabilized, other serious conditions must be handled. Early referrals to specialists are crucial for the correct diagnosis and treatment. If a patient doesn’t need urgent surgery, the focus should be on preventing or treating complications due to a fracture in the temporal bone (bone near the ear).

Facial Paralysis

If a patient has a significant decrease in the activity of some face muscles (measured by ENoG), surgery might be needed. Yet, different surgeons have diverse opinions – some might want to operate right away if they suspect that the facial nerve has been cut; others might choose to wait if a CT scan doesn’t show any obvious problem such as the nerve being pressed by a bone. Even if it’s delayed by up to two months, facial nerve decompression (relieving pressure on the nerve) might help for a better recovery after a temporal bone fracture.

The decompression can be done in two ways – through the bone behind the ear, or by opening the skull; sometimes, both methods are used. No method can fully expose the facial nerve inside the temple. Therefore, many doctors feel that decompression is not complete if these two approaches are not combined. During surgery, it’s more common to find other problems like bone pieces pressing on the nerve, swelling and internal bleeding – rather than seeing that the nerve has been entirely cut.

Leakage of Brain Fluid

For this condition, some simple remedies include raising the head, resting in bed, and avoiding efforts. It’s not completely agreed upon whether antibiotics should be used to prevent meningitis (swelling of the brain) though they often are if the brain fluid keeps leaking after an injury. If the leakage doesn’t stop with these methods, doctors might place a lumbar drain to decrease pressure in the brain. A few patients might need surgery.

Hearing Loss

Doctors can only identify whether the hearing loss is due to problems in conducting sound or problems in the nerves at the bedside. A full evaluation of hearing should be done a few weeks after the injury once any swelling and bleeding in the ear have resolved. If the problem with conducting sound persists, then surgery is recommended. If the nerve related hearing problem persists it might be treated with hearing aids or even an implant for severe cases.

Dizziness

Tests to look at balance should be done once the patient’s neurological state has normalized. This is usually done on an out-patient basis. If the patient develops a leakage of inner ear fluid, then surgical repair is needed. If an accumulation of inner ear fluid is seen after the trauma, it should be managed with steroids and water pills.

Eye Damage

Problems with the eye can occur due to the inability to properly close the eye. This is managed aggressively with the use of eye drops and lubricants, more frequent eye doctor check-ups, and possibly placing a weight in the eyelid early on to help it close.

What else can Temporal Fracture be?

When trying to diagnose a fracture in the temporal bone of the skull, doctors look closely at the symptoms they’re seeing. There are quite a few conditions with similar symptoms, and they group these into categories.

When the patient has lost consciousness or seems confused because of a hit to the head, they might consider:

• Other skull fractures
• Seizures or the state after a seizure
• Diffuse axonal injury
• Concussion
• Epidural hematoma – a build-up of blood between the skull and the outer layer of the brain
• Subdural hematoma – a build-up of blood on the brain’s surface
• Subarachnoid hemorrhage – a specific kind of stroke caused by bleeding on the surface of the brain
• Parenchymal hemorrhage
• Stroke (Cerebral vascular accident)

If they’re looking at symptoms like hearing loss, ringing in the ears (tinnitus), and dizziness (vertigo), they might consider:

• Sudden sensorineural hearing loss
• COVID-19 infection
• Damage to the ossicular chain – tiny bones in the ear
• Perilymphatic fistula – when there’s a hole in the inner ear
• Enlarged vestibular aqueduct
• Middle ear effusion
• Acoustic neuroma – a noncancerous tumor on the nerve that connects the ear to the brain
• Benign paroxysmal positional vertigo – a common cause of dizziness
• Labyrinthitis – inflammation of the inner ear
• Vestibular neuronitis – inflammation of the nerves in the inner ear
• Ménière’s disease – a disorder of the inner ear
• Multiple sclerosis

For symptoms like facial paralysis, they might consider:

• Bell’s palsy – a condition causing temporary facial weakness or paralysis
• Ramsay Hunt syndrome – a reactivation of chickenpox virus in a nerve near the brain
• Lyme disease
• Guillain-Barré syndrome – a rare neurological disorder
• COVID-19 infection
• Intracranial hemorrhage – bleeding within the skull
• Stroke (Cerebral vascular accident)
• A facial nerve tumor or a tumor that affects the facial nerves
• Conductive hearing loss
• Multiple sclerosis

A detailed examination is needed to tell these conditions apart from a fracture in the temporal bone.

What to expect with Temporal Fracture

The recovery from temporal bone fractures often hinges on whether there is a brain injury involved. Most patients without a brain injury have good outcomes, but those with brain involvement generally face a more challenging recovery.

Several factors can affect the recovery process:

* If a facial nerve is damaged and causes partial facial paralysis, it usually responds well to non-invasive treatment and generally has a good chance of recovery. In fact, about 80% of patients with this issue regain normal function. However, if the entire facial nerve is paralyzed, the recovery outlook is less certain—only 57% of patients regain typical facial function. However, most people who experience facial paralysis from a temporal bone fracture will recover to a satisfactory level. Only a small number (1-2%) may continue to experience lasting, relaxed paralysis, unless they undergo surgery to repair the nerve.

In case of a CSF leak, most stop within two weeks with non-invasive measures. Surgical repair may be considered in resistant cases. Hearing loss, which is usually due to blood collecting in the eardrum (hemotympanum), commonly improves on its own. If the chain of tiny bones in the ear (ossicular chain) is disrupted, surgery can repair it effectively. But, recovery from sensorineural hearing loss is unpredictable, with treatments ranging from hearing aids to cochlear implants, depending on the severity.

Moreover, dizziness may get better within several months after the injury. Engaging in physical therapy or specific brain injury rehabilitation programs can enhance long-term results. Meningitis, if it occurs, usually resolves with appropriate antibiotic treatment.

Executing early treatment and remaining watchful for complications is extremely important in improving the overall recovery and reducing the risk of long-term effects.

Possible Complications When Diagnosed with Temporal Fracture

Temporal bone fractures can lead to numerous complications, including:

• Facial paralysis due to damage to cranial nerve VII
• Loss of sense perception hearing due to harm to the inner ear or cranial nerve VIII
• Loss of conductive hearing due to damage to the small bones in the ear, rupture of the eardrum, or blood in the ear
• Dizziness due to damage to cranial nerve VIII, leaks in the ear’s fluid-filled compartments, injuries to the brain, or after-effects of trauma
• Leaks of the fluid that surrounds the brain and spinal cord
• Meningitis, an inflammation of the membranes surrounding the brain
• Paralysis of cranial nerves IX, X, XI
• Tears, blood clots, or both in the internal carotid artery
• Pouch of the lining of the brain pushing through a hole in the skull
• Narrowing of the outer ear canal

Diagnosing these conditions sooner and treating them quickly can lower the risk of these complications from a temporal bone fracture. However, patients may still deal with lasting neurological problems, affecting their quality of life.

Preventing Temporal Fracture

Wearing a helmet is the best way to protect yourself from head injuries. While helmets can’t prevent all head injuries and don’t guard against injuries to the face or neck, they can lower the risk of severe injuries during specific job-related tasks, sports, and leisure activities.

There are also other steps you can take to prevent serious head injuries and their long-lasting effects. These include:

• Driving in a safe manner
• Reducing the chances of falls in people who are prone to them, especially at home
• Avoiding behaviors that can put you at risk
• Living a healthy lifestyle

By promoting safety awareness and taking the right precautions, temporal bone fractures (cracks to the bone near the ear) and related complications can be prevented.