Skull base fracture

Dr. med. Mira Seidel is a freelance writer for the medical team.

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A fracture of the base of the skull (petrous bone fracture, otobasal fracture) is caused by direct force on the skull. Typical symptoms are a bruise around the eyes, facial nerve palsy, and hearing impairment. Treatment is usually conservative. Find out more about the causes, symptoms, diagnosis and treatment of a skull base fracture here.

ICD codes for this disease: ICD codes are internationally recognized codes for medical diagnoses. They can be found, for example, in doctor's letters or on certificates of incapacity for work. S02

Skull base fracture: description

The skull base fracture (skull base fracture) counts as skull fractures (fracture of the skull roof) and the facial skull fracture to the skull fractures. It is generally seen as a dangerous injury, but mostly not because of the fracture itself, but because of the brain, which is often injured at the same time.

Forms of skull base fracture

The most important types of fracture in a skull base fracture are:

• Temporal bone fracture (frontobasal fracture)
• Temporal bone fracture (laterobasal fracture)

Longitudinal temporal bone fractures occur with 70 to 80 percent of the cases significantly more frequently than transverse temporal bone fractures. The fracture runs along the longitudinal axis of the temporal bone, through the roof of the middle ear and the facial nerve canal (facial canal). The ossicles often shift, which disrupts sound conduction. There is also a risk of infection rising up through the external ear canal. This is the case in about 20 percent of all petrous bone fractures.

In transverse temporal bone fractures, the fracture gap begins on the posterior surface of the temporal bone pyramid, crosses the roof of the internal auditory canal and also extends in the direction of the facial nerve canal and / or labyrinth (seat of the inner ear).

Skull base fracture: symptoms

In the case of a fracture of the base of the skull, the symptoms depend on whether it is a longitudinal or transverse fracture of the temporal bone. Since numerous nerves and vessels pass through the base of the skull and can be injured by the bone fracture, various failures occur.

Symptoms of a longitudinal fracture of the temporal temporal bone

A bruise around the eyes (monocle or glasses hematoma) is typical of this type of skull base fracture. The eyelids swell strongly. If the floor of the eye socket is broken, the eyeball can step deeper (blow-out fracture), as a result of which the patient usually sees double images.

In the case of a longitudinal fracture of the temporal bone, the paranasal sinuses are also injured. Steps can also form in the external ear canal. In some patients, the eardrum ruptures and the ossicular chain is interrupted, so that sound conduction is disturbed (conductive hearing loss).

The facial nerve is paralyzed in 15 to 25 percent of all cases of longitudinal fractures. The sense of smell is disturbed by tearing off the olfactory nerves. Nerve fluid or blood can drain out of the nose, ear or mouth.

Symptoms of a transverse temporal bone fracture

The lateral fracture mostly affects the ear: the damage to the inner ear means that the affected person can no longer hear and the sense of balance is lost. Facial nerve paralysis occurs much more frequently than with a longitudinal fracture of the calcaneus. About half of the patients with a transverse temporal bone fracture are affected. Nerve water can also leak through the ear. In the case of transverse temporal bone fractures, there is often a bruise behind the ear, also known as the "battle's sign".

Skull base fracture: causes and risk factors

The fracture of the base of the skull occurs as a result of strong force acting on the skull, for example in the context of traffic accidents or fights. More than half of those affected had a traffic accident, mostly with a frontal impact.

In around 17 percent of all patients with a fracture of the skull, the fracture gap extends into the base of the skull.

A fracture of the skull generally occurs together with a traumatic brain injury (TBI). An isolated fracture of the base of the skull is found in around four percent of all patients with severe head trauma. Due to the swelling in the facial area and because other consequences of the traumatic brain injury are usually in the foreground, the fracture of the base of the skull is often not noticed.

Skull base fracture: examinations and diagnosis

Those affected with a fractured skull base are often injured several times (multiple trauma) and are initially in the intensive care unit. In order to diagnose a skull base fracture, the doctor will first ask the patient - as far as his condition allows - more precisely about the course of the accident and his medical history (anamnesis). Some questions from the doctor might include:

• How did the accident go?
• Do you have pain?
• Have you noticed fluid leaking from your ears, mouth, or nose?
• Do you have trouble speaking, hearing, or seeing?

Physical examinations

The anamnesis interview is followed by physical examinations. In the case of a complex skull base fracture, several doctors from different fields such as neurosurgery, oral and maxillofacial surgery and ear, nose and throat surgery usually work together.

Ears

The doctor examines the patient's external ear canal, paying attention to whether a step or ear secretion has formed. If the eardrum is still intact, blood usually collects in the middle ear (hematotympanum). If possible, the hearing function is then checked. Middle ear hearing loss can be differentiated from inner ear hearing loss with the tuning fork.

The balance can be assessed with the so-called Frenzel glasses. If the balance organ located in the inner ear fails, this leads to eye tremors (nystagmus).

Cranial nerves and large blood vessels

Next, the doctor will examine the basal cranial nerves and large vessels. If you have facial paralysis, it is important to distinguish whether the paralysis developed gradually or was fully developed from the start. This helps to estimate the prognosis and to plan how to proceed.

Secretion leak

If the affected person loses nerve fluid (liquor) or blood from the nose, ear or mouth, this can also be an indication of a skull base fracture. Since nerve water emerging from the nose looks very similar to nasal secretions, a laboratory test is necessary. Special test strips are used to determine the sugar concentration (glucose concentration): the sugar concentration is higher in the nerve water than in the nasal secretion.

Apparative diagnostics

The above-mentioned indications can arouse the suspicion of a skull base fracture, but cannot prove it. A fracture of the base of the skull is difficult to detect even in conventional x-rays. The further diagnosis is therefore always carried out with computed tomography (CT). If the doctor discovers air inside the skull or air-filled bone compartments such as paranasal sinuses and mastoid cells (pneumencephalon) on the images of the brain and facial skull, this indicates a fracture of the base of the skull. A fracture gap does not necessarily have to be visible.

If the person affected has lost hearing or has facial paralysis, magnetic resonance imaging (MRI) is performed. This can be used to rule out a bruise in the brain and show facial nerves.

Skull base fracture: treatment

Patients with a fractured skull should be monitored with bed rest and head elevated for the first 24 hours. In addition, treatment is based on the extent of the base of the skull fracture.

In most cases, conservative treatment is used. However, if bone components are shattered and displaced or if there are penetration points where nerve water escapes, an operation is inevitable. An operation is also necessary in the case of immediate, total facial paralysis (facial paralysis). The procedure is usually only performed once the swelling in the brain has subsided. The exception is a space-occupying bruise.

Skull base fracture: conservative treatment

The injured ear canal is cleaned and covered in a sterile manner. If the fracture of the base of the skull has led to hearing loss in the inner ear, a so-called rheological treatment is initiated, as in the case of sudden hearing loss: Certain active ingredients are used to try to improve the blood circulation in the inner ear. Any dizziness that occurs can be alleviated with special medication (antivertiginous drugs).

If nerve water leaks from the nose, ear or mouth due to the fracture of the skull base, antibiotics must first be treated as a preventive measure in order to avoid an ascending infection. If the defect is in the middle fossa of the skull, with nerve water flowing out of the ear, this gap usually sticks up spontaneously and rarely needs to be treated surgically.

Nerves that are trapped in the fracture gap do not necessarily have to be operated on. Sometimes they can regenerate spontaneously.

Skull base fracture: surgery

In the case of fractures in the area of ​​the anterior cranial fossa (especially the lamina cribrosa), when nerve water drains through the nose, surgery must always be performed. Because the gap does not close spontaneously and an infection can develop even years later. During the operation, the meninges (dura) are first sealed so that they are watertight. Then the bone is reconstructed.

Bleeding caused by ruptured brain vessels must also be surgically stopped. The surgeon removes the bruise that is located in the so-called epidural space. This prevents the pressure in the brain from increasing and causing brain damage.

Skull base fracture: disease course and prognosis

In the case of a skull base fracture, the prognosis varies depending on the type of fracture. A longitudinal fracture usually has a good prognosis and rarely results in consequential damage. In the case of a transverse fracture, in which the inner ear function and the facial nerve have been damaged, permanent damage is to be expected.

Skull base fracture: complications

Possible complications with a skull base fracture are:

• Inflammation of the brain (meningitis)
• Collections of pus (empyema)
• Brain abscess
• Injuries to the carotid artery
• Carotid-cavernous sinus fistula (short-circuit in the blood vessels through which blood flows from the carotid artery into the venous network in the skull)
• permanent cranial nerve lesions

Such complications can worsen the prognosis for a skull base fracture.

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